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Why do we love? A philosophical inquiry | null | TED-Ed | Ah, romantic love - beautiful and intoxicating, heartbreaking and soul-crushing, often all at the same time. Why do we choose to put ourselves through its emotional wringer? Does love make our lives meaningful, or is it an escape from our loneliness and suffering? Is love a disguise for our sexual desire, or a trick of biology to make us procreate? Is it all we need? Do we need it at all? If romantic love has a purpose, neither science nor psychology has discovered it yet. But over the course of history, some of our most respected philosophers have put forward some intriguing theories. Love makes us whole, again. The ancient Greek philosopher Plato explored the idea that we love in order to become complete. In his "Symposium", he wrote about a dinner party, at which Aristophanes, a comic playwright, regales the guests with the following story: humans were once creatures with four arms, four legs, and two faces. One day, they angered the gods, and Zeus sliced them all in two. Since then, every person has been missing half of him or herself. Love is the longing to find a soulmate who'll make us feel whole again, or, at least, that's what Plato believed a drunken comedian would say at a party. Love tricks us into having babies. Much, much later, German philosopher Arthur Schopenhauer maintained that love based in sexual desire was a voluptuous illusion. He suggested that we love because our desires lead us to believe that another person will make us happy, but we are sorely mistaken. Nature is tricking us into procreating, and the loving fusion we seek is consummated in our children. When our sexual desires are satisfied, we are thrown back into our tormented existences, and we succeed only in maintaining the species and perpetuating the cycle of human drudgery. Sounds like somebody needs a hug. Love is escape from our loneliness. According to the Nobel Prize-winning British philosopher Bertrand Russell, we love in order to quench our physical and psychological desires. Humans are designed to procreate, but without the ecstasy of passionate love, sex is unsatisfying. Our fear of the cold, cruel world tempts us to build hard shells to protect and isolate ourselves. Love's delight, intimacy, and warmth helps us overcome our fear of the world, escape our lonely shells, and engage more abundantly in life. Love enriches our whole being, making it the best thing in life. Love is a misleading affliction. Siddhārtha Gautama, who became known as the Buddha, or the Enlightened One, probably would have had some interesting arguments with Russell. Buddha proposed that we love because we are trying to satisfy our base desires. Yet, our passionate cravings are defects, and attachments, even romantic love, are a great source of suffering. Luckily, Buddha discovered the eight-fold path, a sort of program for extinguishing the fires of desire so that we can reach Nirvana, an enlightened state of peace, clarity, wisdom, and compassion. The novelist Cao Xueqin illustrated this Buddhist sentiment that romantic love is folly in one of China's greatest classical novels, "Dream of the Red Chamber." In a subplot, Jia Rui falls in love with Xi-feng who tricks and humiliates him. Conflicting emotions of love and hate tear him apart, so a Taoist gives him a magic mirror that can cure him as long as he doesn't look at the front of it. But of course, he looks at the front of it. He sees Xi-feng. His soul enters the mirror and he is dragged away in iron chains to die. Not all Buddhists think this way about romantic and erotic love, but the moral of this story is that such attachments spell tragedy, and should, along with magic mirrors, be avoided. Love lets us reach beyond ourselves. Let's end on a slightly more positive note. The French philosopher Simone de Beauvoir proposed that love is the desire to integrate with another and that it infuses our lives with meaning. However, she was less concerned with why we love and more interested in how we can love better. She saw that the problem with traditional romantic love is it can be so captivating, that we are tempted to make it our only reason for being. Yet, dependence on another to justify our existence easily leads to boredom and power games. To avoid this trap, Beauvoir advised loving authentically, which is more like a great friendship. Lovers support each other in discovering themselves, reaching beyond themselves, and enriching their lives and the world together. Though we might never know why we fall in love, we can be certain that it will be an emotional rollercoaster ride. It's scary and exhilarating. It makes us suffer and makes us soar. Maybe we lose ourselves. Maybe we find ourselves. It might be heartbreaking, or it might just be the best thing in life. Will you dare to find out? |
The terrors of sleep paralysis | null | TED-Ed | Imagine this: You're fast asleep when all of a sudden you're awoken! And not by your alarm clock. Your eyes open, and there's a demon sitting on your chest, pinning you down. You try to open your mouth and scream, but no sound comes out. You try to get up and run away, but you realize that you are completely immobilized. The demon is trying to suffocate you, but you can't fight back. You've awoken into your dream, and it's a nightmare. It sounds like a Stephen King movie, but it's actually a medical condition called sleep paralysis, and about half of the population has experienced this strange phenomenon at least once in their life. This panic-inducing episode of coming face-to-face with the creatures from your nightmares can last anywhere from seconds to minutes and may involve visual or auditory hallucinations of an evil spirit or an out-of-body feeling like you're floating. Some have even mistaken sleep paralysis for an encounter with a ghost or an alien abduction. In 1867, Dr. Silas Weir Mitchell was the first medical professional to study sleep paralysis. "The subject awakes to consciousness of his environment but is incapable of moving a muscle. Lying to all appearance, still asleep. He's really engaged for a struggle for movement, fraught with acute mental distress. Could he but manage to stir, the spell would vanish instantly." Even though Dr. Mitchell was the first to observe patients in a state of sleep paralysis, it's so common that nearly every culture throughout time has had some kind of paranormal explanation for it. In medieval Europe, you might think that an incubus, a sex-hungry demon in male form, visited you in the night. In Scandinavia, the mare, a damned woman, is responsible for visiting sleepers and sitting on their rib cages. In Turkey, a jinn holds you down and tries to strangle you. In Thailand, Phi Am bruises you while you sleep. In the southern United States, the hag comes for you. In Mexico, you could blame subirse el muerto, the dead person, on you. In Greece, Mora sits upon your chest and tries to asphyxiate you. In Nepal, Khyaak the ghost resides under the staircase. It may be easier to blame sleep paralysis on evil spirits because what's actually happening in your brain is much harder to explain. Modern scientists believe that sleep paralysis is caused by an abnormal overlap of the REM, rapid eye movement, and waking stages of sleep. During a normal REM cycle, you're experiencing a number of sensory stimuli in the form of a dream, and your brain is unconscious and fully asleep. During your dream, special neurotransmitters are released, which paralyze almost all of your muscles. That's called REM atonia. It's what keeps you from running in your bed when you're being chased in your dreams. During an episode of sleep paralysis, you're experiencing normal components of REM. You're dreaming and your muscles are paralyzed, only your brain is conscious and wide awake. This is what causes you to imagine that you're having an encounter with a menacing presence. So this explains the hallucinations, but what about the feelings of panic, strangling, choking, chest pressure that so many people describe? Well during REM, the function that keeps you from acting out your dreams, REM atonia, also removes voluntary control of your breathing. Your breath becomes more shallow and rapid. You take in more carbon dioxide and experience a small blockage of your airway. During a sleep paralysis episode, a combination of your body's fear response to a perceived attack by an evil creature and your brain being wide awake while your body is in an REM sleep state triggers a response for you to take in more oxygen. That makes you gasp for air, but you can't because REM atonia has removed control of your breath. This struggle for air while your body sleeps creates a perceived sensation of pressure on the chest or suffocation. While a few people experience sleep paralysis regularly and it may be linked to sleep disorders such as narcolepsy, many who experience an episode of sleep paralysis do so infrequently, perhaps only once in a lifetime. So you can rest easy, knowing that an evil entity is not trying to haunt, possess, strangle, or suffocate you. Save that for the horror films! |
How a wound heals itself | null | TED-Ed | The largest organ in your body isn't your liver or your brain. It's your skin, with a surface area of about 20 square feet in adults. Though different areas of the skin have different characteristics, much of this surface performs similar functions, such as sweating, feeling heat and cold, and growing hair. But after a deep cut or wound, the newly healed skin will look different from the surrounding area, and may not fully regain all its abilities for a while, or at all. To understand why this happens, we need to look at the structure of the human skin. The top layer, called the epidermis, consists mostly of hardened cells, called keratinocytes, and provides protection. Since its outer layer is constantly being shed and renewed, it's pretty easy to repair. But sometimes a wound penetrates into the dermis, which contains blood vessels and the various glands and nerve endings that enable the skin's many functions. And when that happens, it triggers the four overlapping stages of the regenerative process. The first stage, hemostasis, is the skin's response to two immediate threats: that you're now losing blood and that the physical barrier of the epidermis has been compromised. As the blood vessels tighten to minimize the bleeding, in a process known as vasoconstriction, both threats are averted by forming a blood clot. A special protein known as fibrin forms cross-links on the top of the skin, preventing blood from flowing out and bacteria or pathogens from getting in. After about three hours of this, the skin begins to turn red, signaling the next stage, inflammation. With bleeding under control and the barrier secured, the body sends special cells to fight any pathogens that may have gotten through. Among the most important of these are white blood cells, known as macrophages, which devour bacteria and damage tissue through a process known as phagocytosis, in addition to producing growth factors to spur healing. And because these tiny soldiers need to travel through the blood to get to the wound site, the previously constricted blood vessels now expand in a process called vasodilation. About two to three days after the wound, the proliferative stage occurs, when fibroblast cells begin to enter the wound. In the process of collagen deposition, they produce a fibrous protein called collagen in the wound site, forming connective skin tissue to replace the fibrin from before. As epidermal cells divide to reform the outer layer of skin, the dermis contracts to close the wound. Finally, in the fourth stage of remodeling, the wound matures as the newly deposited collagen is rearranged and converted into specific types. Through this process, which can take over a year, the tensile strength of the new skin is improved, and blood vessels and other connections are strengthened. With time, the new tissue can reach from 50-80% of some of its original healthy function, depending on the severity of the initial wound and on the function itself. But because the skin does not fully recover, scarring continues to be a major clinical issue for doctors around the world. And even though researchers have made significant strides in understanding the healing process, many fundamental mysteries remain unresolved. For instance, do fibroblast cells arrive from the blood vessels or from skin tissue adjacent to the wound? And why do some other mammals, such as deer, heal their wounds much more efficiently and completely than humans? By finding the answers to these questions and others, we may one day be able to heal ourselves so well that scars will be just a memory. |
The history of chocolate | null | TED-Ed | If you can't imagine life without chocolate, you're lucky you weren't born before the 16th century. Until then, chocolate only existed in Mesoamerica in a form quite different from what we know. As far back as 1900 BCE, the people of that region had learned to prepare the beans of the native cacao tree. The earliest records tell us the beans were ground and mixed with cornmeal and chili peppers to create a drink - not a relaxing cup of hot cocoa, but a bitter, invigorating concoction frothing with foam. And if you thought we make a big deal about chocolate today, the Mesoamericans had us beat. They believed that cacao was a heavenly food gifted to humans by a feathered serpent god, known to the Maya as Kukulkan and to the Aztecs as Quetzalcoatl. Aztecs used cacao beans as currency and drank chocolate at royal feasts, gave it to soldiers as a reward for success in battle, and used it in rituals. The first transatlantic chocolate encounter occurred in 1519 when Hernán Cortés visited the court of Moctezuma at Tenochtitlan. As recorded by Cortés's lieutenant, the king had 50 jugs of the drink brought out and poured into golden cups. When the colonists returned with shipments of the strange new bean, missionaries' salacious accounts of native customs gave it a reputation as an aphrodisiac. At first, its bitter taste made it suitable as a medicine for ailments, like upset stomachs, but sweetening it with honey, sugar, or vanilla quickly made chocolate a popular delicacy in the Spanish court. And soon, no aristocratic home was complete without dedicated chocolate ware. The fashionable drink was difficult and time consuming to produce on a large scale. That involved using plantations and imported slave labor in the Caribbean and on islands off the coast of Africa. The world of chocolate would change forever in 1828 with the introduction of the cocoa press by Coenraad van Houten of Amsterdam. Van Houten's invention could separate the cocoa's natural fat, or cocoa butter. This left a powder that could be mixed into a drinkable solution or recombined with the cocoa butter to create the solid chocolate we know today. Not long after, a Swiss chocolatier named Daniel Peter added powdered milk to the mix, thus inventing milk chocolate. By the 20th century, chocolate was no longer an elite luxury but had become a treat for the public. Meeting the massive demand required more cultivation of cocoa, which can only grow near the equator. Now, instead of African slaves being shipped to South American cocoa plantations, cocoa production itself would shift to West Africa with Cote d'Ivoire providing two-fifths of the world's cocoa as of 2015. Yet along with the growth of the industry, there have been horrific abuses of human rights. Many of the plantations throughout West Africa, which supply Western companies, use slave and child labor, with an estimation of more than 2 million children affected. This is a complex problem that persists despite efforts from major chocolate companies to partner with African nations to reduce child and indentured labor practices. Today, chocolate has established itself in the rituals of our modern culture. Due to its colonial association with native cultures, combined with the power of advertising, chocolate retains an aura of something sensual, decadent, and forbidden. Yet knowing more about its fascinating and often cruel history, as well as its production today, tells us where these associations originate and what they hide. So as you unwrap your next bar of chocolate, take a moment to consider that not everything about chocolate is sweet. |
The mathematical secrets of Pascal's triangle | null | TED-Ed | This may look like a neatly arranged stack of numbers, but it's actually a mathematical treasure trove. Indian mathematicians called it the Staircase of Mount Meru. In Iran, it's the Khayyam Triangle. And in China, it's Yang Hui's Triangle. To much of the Western world, it's known as Pascal's Triangle after French mathematician Blaise Pascal, which seems a bit unfair since he was clearly late to the party, but he still had a lot to contribute. So what is it about this that has so intrigued mathematicians the world over? In short, it's full of patterns and secrets. First and foremost, there's the pattern that generates it. Start with one and imagine invisible zeros on either side of it. Add them together in pairs, and you'll generate the next row. Now, do that again and again. Keep going and you'll wind up with something like this, though really Pascal's Triangle goes on infinitely. Now, each row corresponds to what's called the coefficients of a binomial expansion of the form (x+y)^n, where n is the number of the row, and we start counting from zero. So if you make n=2 and expand it, you get (x^2) + 2xy + (y^2). The coefficients, or numbers in front of the variables, are the same as the numbers in that row of Pascal's Triangle. You'll see the same thing with n=3, which expands to this. So the triangle is a quick and easy way to look up all of these coefficients. But there's much more. For example, add up the numbers in each row, and you'll get successive powers of two. Or in a given row, treat each number as part of a decimal expansion. In other words, row two is (1x1) + (2x10) + (1x100). You get 121, which is 11^2. And take a look at what happens when you do the same thing to row six. It adds up to 1,771,561, which is 11^6, and so on. There are also geometric applications. Look at the diagonals. The first two aren't very interesting: all ones, and then the positive integers, also known as natural numbers. But the numbers in the next diagonal are called the triangular numbers because if you take that many dots, you can stack them into equilateral triangles. The next diagonal has the tetrahedral numbers because similarly, you can stack that many spheres into tetrahedra. Or how about this: shade in all of the odd numbers. It doesn't look like much when the triangle's small, but if you add thousands of rows, you get a fractal known as Sierpinski's Triangle. This triangle isn't just a mathematical work of art. It's also quite useful, especially when it comes to probability and calculations in the domain of combinatorics. Say you want to have five children, and would like to know the probability of having your dream family of three girls and two boys. In the binomial expansion, that corresponds to girl plus boy to the fifth power. So we look at the row five, where the first number corresponds to five girls, and the last corresponds to five boys. The third number is what we're looking for. Ten out of the sum of all the possibilities in the row. so 10/32, or 31.25%. Or, if you're randomly picking a five-player basketball team out of a group of twelve friends, how many possible groups of five are there? In combinatoric terms, this problem would be phrased as twelve choose five, and could be calculated with this formula, or you could just look at the sixth element of row twelve on the triangle and get your answer. The patterns in Pascal's Triangle are a testament to the elegantly interwoven fabric of mathematics. And it's still revealing fresh secrets to this day. For example, mathematicians recently discovered a way to expand it to these kinds of polynomials. What might we find next? Well, that's up to you. |
What causes bad breath? | null | TED-Ed | There is a curse that has plagued humanity since ancient times. The Greeks fought it by chewing aromatic resins, while the Chinese resorted to egg shells. In the ancient Jewish Talmud, it's even considered legal grounds for divorce. This horrible scourge is halitosis, otherwise known as bad breath. But what causes it, and why is it so universally terrifying? Well, think of some of the worst odors you can imagine, like garbage, feces or rotting meat. All of these smells come from the activity of microorganisms, particularly bacteria, and, as disgusting as it may sound, similar bacteria live in the moisture-rich environment of your mouth. Don't panic. The presence of bacteria in your body is not only normal, it's actually vital for all sorts of things, like digestion and disease prevention. But like all living things, bacteria need to eat. The bacteria in your mouth feed off of mucus, food remnants, and dead tissue cells. In order to absorb nutrients through their cell membranes, they must break down the organic matter into much smaller molecules. For example, they'll break proteins into their component amino acids and then break those down even further into various compounds. Some of the foul-smelling byproducts of these reactions, such as hydrogen sulfide and cadaverine, escape into the air and waft their way towards unsuspecting noses. Our sensitivity to these odors and interpretation of them as bad smells may be an evolutionary mechanism warning us of rotten food and the presence of disease. Smell is one of our most intimate and primal senses, playing a huge role in our attraction to potential mates. In one poll, 59% of men and 70% of women said they wouldn't go on a date with someone who has bad breath, which may be why Americans alone spend $1 billion a year on various breath products. Fortunately, most bad breath is easily treated. The worst smelling byproducts come from gram-negative bacteria that live in the spaces between gums and teeth and on the back of the tongue. By brushing and flossing our teeth, using antibacterial mouthwash at bedtime, gently cleaning the back of the tongue with a plastic scraper and even just eating a healthy breakfast, we can remove many of these bacteria and their food sources. In some cases, these measures may not be enough due to dental problems, nasal conditions, or rarer ailments, such as liver disease and uncontrolled diabetes. Behaviors like smoking and excessive alcohol consumption also have a very recognizable odor. Regardless of cause, the bad smell almost always originates in the mouth and not the stomach or elsewhere in the body. But one of the biggest challenges lies in actually determining how our breath smells in the first place, and it's unclear why. It may be that we're too acclimatized to the smell inside our own mouths to judge it. And methods like cupping your hands over your mouth, or licking and smelling your wrist don't work perfectly either. One study showed that even when people do this, they tend to rate the smell subjectively according to how bad they thought it was going to be. But there's one simple, if socially difficult, way of finding out how your breath smells: just take a deep breath and ask a friend. |
History vs. Napoleon Bonaparte | null | TED-Ed | After the French Revolution erupted in 1789, Europe was thrown into chaos. Neighboring countries' monarchs feared they would share the fate of Louis XVI, and attacked the New Republic, while at home, extremism and mistrust between factions lead to bloodshed. In the midst of all this conflict, a powerful figure emerged to take charge of France. But did he save the revolution or destroy it? "Order, order, who's the defendant today? I don't see anyone." "Your Honor, this is Napoléon Bonaparte, the tyrant who invaded nearly all of Europe to compensate for his personal stature-based insecurities." "Actually, Napoléon was at least average height for his time. The idea that he was short comes only from British wartime propaganda. And he was no tyrant. He was safeguarding the young Republic from being crushed by the European monarchies." "By overthrowing its government and seizing power himself?" "Your Honor, as a young and successful military officer, Napoléon fully supported the French Revolution, and its ideals of liberty, equality, and fraternity. But the revolutionaries were incapable of real leadership. Robespierre and the Jacobins who first came to power unleashed a reign of terror on the population, with their anti-Catholic extremism and nonstop executions of everyone who disagreed with them. And The Directory that replaced them was an unstable and incompetent oligarchy. They needed a strong leader who could govern wisely and justly." "So, France went through that whole revolution just to end up with another all-powerful ruler?" "Not quite. Napoléon's new powers were derived from the constitution that was approved by a popular vote in the Consulate." "Ha! The constitution was practically dictated at gunpoint in a military coup, and the public only accepted the tyrant because they were tired of constant civil war." "Be that as it may, Napoléon introduced a new constitution and a legal code that kept some of the most important achievements of the revolution in tact: freedom of religion abolition of hereditary privilege, and equality before the law for all men." "All men, indeed. He deprived women of the rights that the revolution had given them and even reinstated slavery in the French colonies. Haiti is still recovering from the consequences centuries later. What kind of equality is that?" "The only kind that could be stably maintained at the time, and still far ahead of France's neighbors." "Speaking of neighbors, what was with all the invasions?" "Great question, Your Honor." "Which invasions are we talking about? It was the neighboring empires who had invaded France trying to restore the monarchy, and prevent the spread of liberty across Europe, twice by the time Napoléon took charge. Having defended France as a soldier and a general in those wars, he knew that the best defense is a good offense." "An offense against the entire continent? Peace was secured by 1802, and other European powers recognized the new French Regime. But Bonaparte couldn't rest unless he had control of the whole continent, and all he knew was fighting. He tried to enforce a European-wide blockade of Britain, invaded any country that didn't comply, and launched more wars to hold onto his gains. And what was the result? Millions dead all over the continent, and the whole international order shattered." "You forgot the other result: the spread of democratic and liberal ideals across Europe. It was thanks to Napoléon that the continent was reshaped from a chaotic patchwork of fragmented feudal and religious territories into efficient, modern, and secular nation states where the people held more power and rights than ever before." "Should we also thank him for the rise of nationalism and the massive increase in army sizes? You can see how well that turned out a century later." "So what would European history have been like if it weren't for Napoléon?" "Unimaginably better/worse." Napoléon seemingly unstoppable momentum would die in the Russian winter snows, along with most of his army. But even after being deposed and exiled, he refused to give up, escaping from his prison and launching a bold attempt at restoring his empire before being defeated for the second and final time. Bonaparte was a ruler full of contradictions, defending a popular revolution by imposing absolute dictatorship, and spreading liberal ideals through imperial wars, and though he never achieved his dream of conquering Europe, he undoubtedly left his mark on it, for better or for worse. |
"My Man" / "Bohanna" / "We Dance" | {0: 'Crush Club combines the star power of vocalist TC Milan and producer and multi-instrumentalist Le Chev.'} | TED Salon: Radical Craft | (Music) TC Milan: How you doing tonight? New York! (Music) Here we go. (Singing) I don't need another lover I got my friends No, I don't need another mother — bet that you can guess Oh baby, can you talk right act tight, don't fight follow my rules? Oh baby, can you stay sweet upbeat fill me with all your cool? Are you man enough for me? Nicki B: Are you man enough for me? TM: Are you man enough to be? NB: Are you man enough to be? TM: Are you man enough for me? NB: Are you man enough for me? TM: Oh, are you man enough to be? NB: Are you man enough to be? TM: C'mon. (Singing) Be my man (Music) That's right. (Music) Give it to 'em. NB: Hit it good, c'mon, do better, give me all the feel Oooh Keep it hot, assess my pleasure Just keep it real TM: Are you man enough for me? NB: Are you man enough for me? TM: Are you man enough to be? NB: Are you man enough to be? TM: Are you man enough for me? NB: Are you man enough for me? TM: Are you man enough to be? NB: Are you man enough to be? TM: What? (Singing) Be my man (Music) NB: Be my man TM: C'mon, Che-Che. (Music) (Music changes) Alright, this next one's "Bohanna." (Singing) All the way back to where we began Out of the mess they put us in Le Chev: Bang, bang, off the chain (Singing) Oooh LC: Bang, bang, through the pain (Singing) Oh LC: Bang, bang, off the chain (Singing) Oooh LC: Bang, bang, through the pain One, two, three, let's go! (Singing) Bohanna Music for dancing Bohanna Flowers where you go Bohanna Music for dancing Bohanna We clap, clap our hands for you NB: Little bit of rain makes the window shine — TC: Window shine NB: Dance with Bohanna, drink that red, red wine TM: Red, red wine NB: Little bit of rain makes the window shine TM: Window shine NB: Dance with Bohanna, drink that red, red wine Bohanna Music for dancing Bohanna Flowers where you go Bohanna Music for dancing Bohanna We clap, clap our hands for you (Music) (Music changes) TM: This is the last song. (Cheers) Thank you! (Music) (Singing) I was broken down torn up and turned around I got lost in the darkest cloud I felt there was no way out No I almost lost control I forgot what I was living for But I still got my energy and the music gives me all I need We dance, we make the club our own We chant at night to free our souls It's that time of the night when the music is right Hey, DJ, won't you play my song one more time? We dance Oooh We dance, we make the club our home We chant at night to free our souls You've been kicked around beat up and beat down And when you make a joyful sound — oh ... Someone's there to shut it down So much to overcome That struggle it's never, never done Still got that energy And the music gives you all you need We dance, we make the club our own We chant at night to free our souls It's that time of the night when the music is right Hey, DJ, won't you play my song one more time? We dance (Music) We dance, we make the club our own We chant at night to free our souls We dance, we make the club our home — TM: Can you guys clap with us? (Singing) We chant at night to free our souls TM: Alright, New York. It's that time. It's that TED Talks time. We're sitting down but we're grooving out, right? (Singing) We dance TM: You know we dance After this, we're going to go dance, all of us, altogether at Chever's house. (Singing) We dance (Clapping) Alright, now we're just going to do a simple wave, right? Easy, from our seats. (Singing) We dance NB: Uh huh. TM: There we go. (Singing) We dance TM: One, two, one, two, three — (Singing) We dance, we make the club our home We chant at night to free our souls It's that time of the night when the music is right Hey, DJ, won't you play my song one more time? We dance Oooh. We dance, we make the club our own We chant at night to free our souls We dance (Music ends) Thank you. (Applause and cheers) |
Should you trust unanimous decisions? | null | TED-Ed | Imagine a police lineup where ten witnesses are asked to identify a bank robber they glimpsed fleeing the crime scene. If six of them pick out the same person, there's a good chance that's the real culprit, and if all ten make the same choice, you might think the case is rock solid, but you'd be wrong. For most of us, this sounds pretty strange. After all, much of our society relies on majority vote and consensus, whether it's politics, business, or entertainment. So it's natural to think that more consensus is a good thing. And up until a certain point, it usually is. But sometimes, the closer you start to get to total agreement, the less reliable the result becomes. This is called the paradox of unanimity. The key to understanding this apparent paradox is in considering the overall level of uncertainty involved in the type of situation you're dealing with. If we asked witnesses to identify the apple in this lineup, for example, we shouldn't be surprised by a unanimous verdict. But in cases where we have reason to expect some natural variance, we should also expect varied distribution. If you toss a coin one hundred times, you would expect to get heads somewhere around 50% of the time. But if your results started to approach 100% heads, you'd suspect that something was wrong, not with your individual flips, but with the coin itself. Of course, suspect identifications aren't as random as coin tosses, but they're not as clear cut as telling apples from bananas, either. In fact, a 1994 study found that up to 48% of witnesses tend to pick the wrong person out of a lineup, even when many are confident in their choice. Memory based on short glimpses can be unreliable, and we often overestimate our own accuracy. Knowing all this, a unanimous identification starts to seem less like certain guilt, and more like a systemic error, or bias in the lineup. And systemic errors don't just appear in matters of human judgement. From 1993-2008, the same female DNA was found in multiple crime scenes around Europe, incriminating an elusive killer dubbed the Phantom of Heilbronn. But the DNA evidence was so consistent precisely because it was wrong. It turned out that the cotton swabs used to collect the DNA samples had all been accidentally contaminated by a woman working in the swab factory. In other cases, systematic errors arise through deliberate fraud, like the presidential referendum held by Saddam Hussein in 2002, which claimed a turnout of 100% of voters with all 100% supposedly voting in favor of another seven-year term. When you look at it this way, the paradox of unanimity isn't actually all that paradoxical. Unanimous agreement is still theoretically ideal, especially in cases when you'd expect very low odds of variability and uncertainty, but in practice, achieving it in situations where perfect agreement is highly unlikely should tell us that there's probably some hidden factor affecting the system. Although we may strive for harmony and consensus, in many situations, error and disagreement should be naturally expected. And if a perfect result seems too good to be true, it probably is. |
The science of symmetry | null | TED-Ed | When you hear the word symmetry, maybe you picture a simple geometric shape like a square or a triangle, or the complex pattern on a butterfly's wings. If you are artistically inclined, you might think of the subtle modulations of a Mozart concerto, or the effortless poise of a prima ballerina. When used in every day life, the word symmetry represents vague notions of beauty, harmony and balance. In math and science, symmetry has a different, and very specific, meaning. In this technical sense, a symmetry is the property of an object. Pretty much any type of object can have symmetry, from tangible things like butterflies, to abstract entities like geometric shapes. So, what does it mean for an object to be symmetric? Here's the definition: a symmetry is a transformation that leaves that object unchanged. Okay, that sounds a bit abstract, so let's unpack it. It will help to look at a particular example, like this equilateral triangle. If we rotate our triangle through 120 degrees, around an access through its center, we end up with a triangle that's identical to the original. In this case, the object is the triangle, and the transformation that leaves the object unchanged is rotation through 120 degrees. So we can say an equilateral triangle is symmetric with respect to rotations of 120 degrees around its center. If we rotated the triangle by, say, 90 degrees instead, the rotated triangle would look different to the original. In other words, an equilateral triangle is not symmetric with respect to rotations of 90 degrees around its center. But why do mathematicians and scientists care about symmetries? Turns out, they're essential in many fields of math and science. Let's take a close look at one example: symmetry in biology. You might have noticed that there's a very familiar kind of symmetry we haven't mentioned yet: the symmetry of the right and left sides of the human body. The transformation that gives this symmetry is reflection by an imaginary mirror that slices vertically through the body. Biologists call this bilateral symmetry. As with all symmetries found in living things, it's only approximate, but still a striking feature of the human body. We humans aren't the only bilaterally symmetric organisms. Many other animals, foxes, sharks, beetles, that butterfly we mentioned earlier, have this kind of symmetry, as do some plants like orchid flowers. Other organisms have different symmetries, ones that only become apparent when you rotate the organism around its center point. It's a lot like the rotational symmetry of the triangle we watched earlier. But when it occurs in animals, this kind of symmetry is known as radial symmetry. For instance, some sea urchins and starfish have pentaradial or five-fold symmetry, that is, symmetry with respect to rotations of 72 degrees around their center. This symmetry also appears in plants, as you can see for yourself by slicing through an apple horizontally. Some jellyfish are symmetric with respect to rotations of 90 degrees, while sea anemones are symmetric when you rotate them at any angle. Some corals, on the other hand, have no symmetry at all. They are completely asymmetric. But why do organisms exhibit these different symmetries? Does body symmetry tell us anything about an animal's lifestyle? Let's look at one particular group: bilaterally symmetric animals. In this camp, we have foxes, beetles, sharks, butterflies, and, of course, humans. The thing that unites bilaterally symmetric animals is that their bodies are designed around movement. If you want to pick one direction and move that way, it helps to have a front end where you can group your sensory organs— your eyes, ears and nose. It helps to have your mouth there too since you're more likely to run into food or enemies from this end. You're probably familiar with a name for a group of organs, plus a mouth, mounted on the front of an animal's body. It's called a head. Having a head leads naturally to the development of bilateral symmetry. And it also helps you build streamlined fins if you're a fish, aerodynamic wings if you're a bird, or well coordinated legs for running if you're a fox. But, what does this all have to do with evolution? Turns out, biologists can use these various body symmetries to figure out which animals are related to which. For instance, we saw that starfish and sea urchins have five-fold symmetry. But really what we should have said was adult starfish and sea urchins. In their larval stage, they're bilateral, just like us humans. For biologists, this is strong evidence that we're more closely related to starfish than we are, to say, corals, or other animals that don't exhibit bilateral symmetry at any stage in their development. One of the most fascinating and important problems in biology is reconstructing the tree of life, discovering when and how the different branches diverged. Thinking about something as simple as body symmetry can help us dig far into our evolutionary past and understand where we, as a species, have come from. |
How does anesthesia work? | null | TED-Ed | If you've had surgery, you might remember starting to count backwards from ten, nine, eight, and then waking up with the surgery already over before you even got to five. And it might seem like you were asleep, but you weren't. You were under anesthesia, which is much more complicated. You were unconscious, but you also couldn't move, form memories, or, hopefully, feel pain. Without being able to block all those processes at once, many surgeries would be way too traumatic to perform. Ancient medical texts from Egypt, Asia and the Middle East all describe early anesthetics containing things like opium poppy, mandrake fruit, and alcohol. Today, anesthesiologists often combine regional, inhalational and intravenous agents to get the right balance for a surgery. Regional anesthesia blocks pain signals from a specific part of the body from getting to the brain. Pain and other messages travel through the nervous system as electrical impulses. Regional anesthetics work by setting up an electrical barricade. They bind to the proteins in neurons' cell membranes that let charged particles in and out, and lock out positively charged particles. One compound that does this is cocaine, whose painkilling effects were discovered by accident when an ophthalmology intern got some on his tongue. It's still occasionally used as an anesthetic, but many of the more common regional anesthetics have a similar chemical structure and work the same way. But for major surgeries where you need to be unconscious, you'll want something that acts on the entire nervous system, including the brain. That's what inhalational anesthetics do. In Western medicine, diethyl ether was the first common one. It was best known as a recreational drug until doctors started to realize that people sometimes didn't notice injuries they received under the influence. In the 1840s, they started sedating patients with ether during dental extractions and surgeries. Nitrous oxide became popular in the decades that followed and is still used today. although ether derivatives, like sevoflurane, are more common. Inhalational anesthesia is usually supplemented with intravenous anesthesia, which was developed in the 1870s. Common intravenous agents include sedatives, like propofol, which induce unconsciousness, and opioids, like fentanyl, which reduce pain. These general anesthetics also seem to work by affecting electrical signals in the nervous system. Normally, the brain's electrical signals are a chaotic chorus as different parts of the brain communicate with each other. That connectivity keeps you awake and aware. But as someone becomes anesthetized, those signals become calmer and more organized, suggesting that different parts of the brain aren't talking to each other anymore. There's a lot we still don't know about exactly how this happens. Several common anesthetics bind to the GABA-A receptor in the brain's neurons. They hold the gateway open, letting negatively charged particles flow into the cell. Negative charge builds up and acts like a log jam, keeping the neuron from transmitting electrical signals. The nervous system has lots of these gated channels, controlling pathways for movement, memory, and consciousness. Most anesthetics probably act on more than one, and they don't act on just the nervous system. Many anesthetics also affect the heart, lungs, and other vital organs. Just like early anesthetics, which included familiar poisons like hemlock and aconite, modern drugs can have serious side effects. So an anesthesiologist has to mix just the right balance of drugs to create all the features of anesthesia, while carefully monitoring the patient's vital signs, and adjusting the drug mixture as needed. Anesthesia is complicated, but figuring out how to use it allowed for the development of new and better surgical techniques. Surgeons could learn how to routinely and safely perform C-sections, reopen blocked arteries, replace damaged livers and kidneys, and many other life-saving operations. And each year, new anesthesia techniques are developed that will ensure more and more patients survive the trauma of surgery. |
How to keep human bias out of AI | {0: 'Kriti Sharma creates AI technology to help address some of the toughest social challenges of our time -- from domestic violence to sexual health and inequality.'} | TEDxWarwick | How many decisions have been made about you today, or this week or this year, by artificial intelligence? I build AI for a living so, full disclosure, I'm kind of a nerd. And because I'm kind of a nerd, wherever some new news story comes out about artificial intelligence stealing all our jobs, or robots getting citizenship of an actual country, I'm the person my friends and followers message freaking out about the future. We see this everywhere. This media panic that our robot overlords are taking over. We could blame Hollywood for that. But in reality, that's not the problem we should be focusing on. There is a more pressing danger, a bigger risk with AI, that we need to fix first. So we are back to this question: How many decisions have been made about you today by AI? And how many of these were based on your gender, your race or your background? Algorithms are being used all the time to make decisions about who we are and what we want. Some of the women in this room will know what I'm talking about if you've been made to sit through those pregnancy test adverts on YouTube like 1,000 times. Or you've scrolled past adverts of fertility clinics on your Facebook feed. Or in my case, Indian marriage bureaus. (Laughter) But AI isn't just being used to make decisions about what products we want to buy or which show we want to binge watch next. I wonder how you'd feel about someone who thought things like this: "A black or Latino person is less likely than a white person to pay off their loan on time." "A person called John makes a better programmer than a person called Mary." "A black man is more likely to be a repeat offender than a white man." You're probably thinking, "Wow, that sounds like a pretty sexist, racist person," right? These are some real decisions that AI has made very recently, based on the biases it has learned from us, from the humans. AI is being used to help decide whether or not you get that job interview; how much you pay for your car insurance; how good your credit score is; and even what rating you get in your annual performance review. But these decisions are all being filtered through its assumptions about our identity, our race, our gender, our age. How is that happening? Now, imagine an AI is helping a hiring manager find the next tech leader in the company. So far, the manager has been hiring mostly men. So the AI learns men are more likely to be programmers than women. And it's a very short leap from there to: men make better programmers than women. We have reinforced our own bias into the AI. And now, it's screening out female candidates. Hang on, if a human hiring manager did that, we'd be outraged, we wouldn't allow it. This kind of gender discrimination is not OK. And yet somehow, AI has become above the law, because a machine made the decision. That's not it. We are also reinforcing our bias in how we interact with AI. How often do you use a voice assistant like Siri, Alexa or even Cortana? They all have two things in common: one, they can never get my name right, and second, they are all female. They are designed to be our obedient servants, turning your lights on and off, ordering your shopping. You get male AIs too, but they tend to be more high-powered, like IBM Watson, making business decisions, Salesforce Einstein or ROSS, the robot lawyer. So poor robots, even they suffer from sexism in the workplace. (Laughter) Think about how these two things combine and affect a kid growing up in today's world around AI. So they're doing some research for a school project and they Google images of CEO. The algorithm shows them results of mostly men. And now, they Google personal assistant. As you can guess, it shows them mostly females. And then they want to put on some music, and maybe order some food, and now, they are barking orders at an obedient female voice assistant. Some of our brightest minds are creating this technology today. Technology that they could have created in any way they wanted. And yet, they have chosen to create it in the style of 1950s "Mad Man" secretary. Yay! But OK, don't worry, this is not going to end with me telling you that we are all heading towards sexist, racist machines running the world. The good news about AI is that it is entirely within our control. We get to teach the right values, the right ethics to AI. So there are three things we can do. One, we can be aware of our own biases and the bias in machines around us. Two, we can make sure that diverse teams are building this technology. And three, we have to give it diverse experiences to learn from. I can talk about the first two from personal experience. When you work in technology and you don't look like a Mark Zuckerberg or Elon Musk, your life is a little bit difficult, your ability gets questioned. Here's just one example. Like most developers, I often join online tech forums and share my knowledge to help others. And I've found, when I log on as myself, with my own photo, my own name, I tend to get questions or comments like this: "What makes you think you're qualified to talk about AI?" "What makes you think you know about machine learning?" So, as you do, I made a new profile, and this time, instead of my own picture, I chose a cat with a jet pack on it. And I chose a name that did not reveal my gender. You can probably guess where this is going, right? So, this time, I didn't get any of those patronizing comments about my ability and I was able to actually get some work done. And it sucks, guys. I've been building robots since I was 15, I have a few degrees in computer science, and yet, I had to hide my gender in order for my work to be taken seriously. So, what's going on here? Are men just better at technology than women? Another study found that when women coders on one platform hid their gender, like myself, their code was accepted four percent more than men. So this is not about the talent. This is about an elitism in AI that says a programmer needs to look like a certain person. What we really need to do to make AI better is bring people from all kinds of backgrounds. We need people who can write and tell stories to help us create personalities of AI. We need people who can solve problems. We need people who face different challenges and we need people who can tell us what are the real issues that need fixing and help us find ways that technology can actually fix it. Because, when people from diverse backgrounds come together, when we build things in the right way, the possibilities are limitless. And that's what I want to end by talking to you about. Less racist robots, less machines that are going to take our jobs — and more about what technology can actually achieve. So, yes, some of the energy in the world of AI, in the world of technology is going to be about what ads you see on your stream. But a lot of it is going towards making the world so much better. Think about a pregnant woman in the Democratic Republic of Congo, who has to walk 17 hours to her nearest rural prenatal clinic to get a checkup. What if she could get diagnosis on her phone, instead? Or think about what AI could do for those one in three women in South Africa who face domestic violence. If it wasn't safe to talk out loud, they could get an AI service to raise alarm, get financial and legal advice. These are all real examples of projects that people, including myself, are working on right now, using AI. So, I'm sure in the next couple of days there will be yet another news story about the existential risk, robots taking over and coming for your jobs. (Laughter) And when something like that happens, I know I'll get the same messages worrying about the future. But I feel incredibly positive about this technology. This is our chance to remake the world into a much more equal place. But to do that, we need to build it the right way from the get go. We need people of different genders, races, sexualities and backgrounds. We need women to be the makers and not just the machines who do the makers' bidding. We need to think very carefully what we teach machines, what data we give them, so they don't just repeat our own past mistakes. So I hope I leave you thinking about two things. First, I hope you leave thinking about bias today. And that the next time you scroll past an advert that assumes you are interested in fertility clinics or online betting websites, that you think and remember that the same technology is assuming that a black man will reoffend. Or that a woman is more likely to be a personal assistant than a CEO. And I hope that reminds you that we need to do something about it. And second, I hope you think about the fact that you don't need to look a certain way or have a certain background in engineering or technology to create AI, which is going to be a phenomenal force for our future. You don't need to look like a Mark Zuckerberg, you can look like me. And it is up to all of us in this room to convince the governments and the corporations to build AI technology for everyone, including the edge cases. And for us all to get education about this phenomenal technology in the future. Because if we do that, then we've only just scratched the surface of what we can achieve with AI. Thank you. (Applause) |
What's the difference between accuracy and precision? | null | TED-Ed | As the story goes, the legendary marksman William Tell was forced into a cruel challenge by a corrupt lord. William's son was to be executed unless William could shoot an apple off his head. William succeeded, but let's imagine two variations on the tale. In the first variation, the lord hires a bandit to steal William's trusty crossbow, so he is forced to borrow an inferior one from a peasant. However, the borrowed crossbow isn't adjusted perfectly, and William finds that his practice shots cluster in a tight spread beneath the bullseye. Fortunately, he has time to correct for it before it's too late. Variation two: William begins to doubt his skills in the long hours before the challenge and his hand develops a tremor. His practice shots still cluster around the apple but in a random pattern. Occasionally, he hits the apple, but with the wobble, there is no guarantee of a bullseye. He must settle his nervous hand and restore the certainty in his aim to save his son. At the heart of these variations are two terms often used interchangeably: accuracy and precision. The distinction between the two is actually critical for many scientific endeavours. Accuracy involves how close you come to the correct result. Your accuracy improves with tools that are calibrated correctly and that you're well-trained on. Precision, on the other hand, is how consistently you can get that result using the same method. Your precision improves with more finely incremented tools that require less estimation. The story of the stolen crossbow was one of precision without accuracy. William got the same wrong result each time he fired. The variation with the shaky hand was one of accuracy without precision. William's bolts clustered around the correct result, but without certainty of a bullseye for any given shot. You can probably get away with low accuracy or low precision in everyday tasks. But engineers and researchers often require accuracy on microscopic levels with a high certainty of being right every time. Factories and labs increase precision through better equipment and more detailed procedures. These improvements can be expensive, so managers must decide what the acceptable uncertainty for each project is. However, investments in precision can take us beyond what was previously possible, even as far as Mars. It may surprise you that NASA does not know exactly where their probes are going to touch down on another planet. Predicting where they will land requires extensive calculations fed by measurements that don't always have a precise answer. How does the Martian atmosphere's density change at different elevations? What angle will the probe hit the atmosphere at? What will be the speed of the probe upon entry? Computer simulators run thousands of different landing scenarios, mixing and matching values for all of the variables. Weighing all the possibilities, the computer spits out the potential area of impact in the form of a landing ellipse. In 1976, the landing ellipse for the Mars Viking Lander was 62 x 174 miles, nearly the area of New Jersey. With such a limitation, NASA had to ignore many interesting but risky landing areas. Since then, new information about the Martian atmosphere, improved spacecraft technology, and more powerful computer simulations have drastically reduced uncertainty. In 2012, the landing ellipse for the Curiosity Lander was only 4 miles wide by 12 miles long, an area more than 200 times smaller than Viking's. This allowed NASA to target a specific spot in Gale Crater, a previously un-landable area of high scientific interest. While we ultimately strive for accuracy, precision reflects our certainty of reliably achieving it. With these two principles in mind, we can shoot for the stars and be confident of hitting them every time. |
Why do we hiccup? | null | TED-Ed | Charles Osborne began to hiccup in 1922 after a hog fell on top of him. He wasn't cured until 68 years later and is now listed by Guinness as the world record holder for hiccup longevity. Meanwhile, Florida teen Jennifer Mee may hold the record for the most frequent hiccups, 50 times per minute for more than four weeks in 2007. So what causes hiccups? Doctors point out that a round of hiccups often follows from stimuli that stretch the stomach, like swallowing air or too rapid eating or drinking. Others associate hiccups with intense emotions or a response to them: laughing, sobbing, anxiety, and excitement. Let's look at what happens when we hiccup. It begins with an involuntary spasm or sudden contraction of the diaphragm, the large dome-shaped muscle below our lungs that we use to inhale air. This is followed almost immediately by the sudden closure of the vocal chords and the opening between them, which is called the glottis. The movement of the diaphragm initiates a sudden intake of air, but the closure of the vocal chords stops it from entering the wind pipe and reaching the lungs. It also creates the characteristic sound: "hic." To date, there is no known function for hiccups. They don't seem to provide any medical or physiological advantage. Why begin to inhale air only to suddenly stop it from actually entering the lungs? Anatomical structures, or physiological mechanisms, with no apparent purpose present challenges to evolutionary biologists. Do such structures serve some hidden function that hasn't yet been discovered? Or are they relics of our evolutionary past, having once served some important purpose only to persist into the present as vestigial remnants? One idea is that hiccups began many millions of years before the appearance of humans. The lung is thought to have evolved as a structure to allow early fish, many of which lived in warm, stagnant water with little oxygen, to take advantage of the abundant oxygen in the air overhead. When descendants of these animals later moved onto land, they moved from gill-based ventilation to air-breathing with lungs. That's similar to the much more rapid changes faced by frogs today as they transition from tadpoles with gills to adults with lungs. This hypothesis suggests that the hiccup is a relic of the ancient transition from water to land. An inhalation that could move water over gills followed by a rapid closure of the glottis preventing water from entering the lungs. That's supported by evidence which suggests that the neural patterning involved in generating a hiccup is almost identical to that responsible for respiration in amphibians. Another group of scientists believe that the reflex is retained in us today because it actually provides an important advantage. They point out that true hiccups are found only in mammals and that they're not retained in birds, lizards, turtles, or any other exclusively air-breathing animals. Further, hiccups appear in human babies long before birth and are far more common in infants that adults. Their explanation for this involves the uniquely mammalian activity of nursing. The ancient hiccup reflex may have been adapted by mammals to help remove air from the stomach as a sort of glorified burp. The sudden expansion of the diaphragm would raise air from the stomach, while a closure of the glottis would prevent milk from entering the lungs. Sometimes, a bout of hiccups will go on and on, and we try home remedies: sipping continuously from a glass of cold water, holding one's breath, a mouthful of honey or peanut butter, breathing into a paper bag, or being suddenly frightened. Unfortunately, scientists have yet to verify that any one cure works better or more consistently than others. However, we do know one thing that definitely doesn't work. |
The case of the vanishing honeybees | null | TED-Ed | There is an environmental mystery afoot, and it begins with a seemingly trivial detail that reveals a disaster of global proportions. One day, you notice that the honey you slather on your morning toast is more expensive. Instead of switching to jam, you investigate the reason for the price hike. What you find is shocking. The number of domesticated honeybees in the US has been decreasing at an alarming rate. This decline appears too big to be explained by the usual causes of bee death alone: disease, parasites or starvation. A typical crime scene has almost no adult bees left in the hive, except, perhaps, a lonely queen and a few other survivors. It's full of untouched food stores and a brood of unborn larvae, suggesting that the adults vacated without waiting for them to hatch. But what's particularly eerie is that there's no tell-tale mass of dead or dying bees nearby. Either they have forgotten their way back to the hive, or they have simply disappeared. These mysterious disappearances aren't new. Humans have been collecting honey for centuries. But it wasn't until European settlers in the 1600's introduced the subspecies, Apis mellifera, that we domesticated bees. Since the 19th century, beekeepers have reported occasional mass disappearances, giving them enigmatic names like disappearing disease, spring dwindle disease and autumn collapse. But when in 2006 such losses were found to affect more than half of all hives in the US, the phenomenon got a new name: colony collapse disorder. The most frightening thing about this mystery isn't that we'll have to go back to using regular sugar in our tea. We farm bees for their honey, but they also pollinate our crops on an industrial scale, generating over 1/3 of America's food production this way. So, how can we find the culprit behind this calamity? Here are three of the possible offenders. Exhibit A: Pests and Disease. Most infamous is the varroa mite, a minuscule red pest that not only invades colonies and feeds on bees, but also transfers pathogens that stunt bee growth and shortens their life span. Exhibit B: Genetics. The queen is the core of a healthy hive. But nowadays, the millions of queen bees distributed in commercial hives are bred from just a few original queens, which raises the worry about a lack of genetic diversity which could weaken bees' defenses against pathogens and pests. Exhibit C: Chemicals. Pesticides used both on commercial beehives and agricultural crops to ward off parasites could be getting into the food and water that honeybees consume. Researchers have even found that some pesticides damage the honeybees' homing abilities. So we have a file full of clues but no clear leads. In reality, scientists, the actual detectives on this case, face disagreement over what causes colony collapse disorder. For now, we assume that several factors are the cause. Honeybees aren't necessarily in danger of extinction, but fewer bees overall means less pollination and higher food costs, so it's crucial that scientists solve the case of the vanishing bees. Because while having less honey might be a buzzkill, crop shortages are something that would truly sting. |
Why are sloths so slow? | null | TED-Ed | In 1796, Thomas Jefferson received a box of bones he couldn't identify. A long, sharp claw reminded him of a lion, but the arm bones suggested a larger animal, one about three meters long. Thinking it might be huge unknown species of North American lion, Jefferson warned explorers Lewis and Clark to keep an eye out for this mysterious predator. But Jefferson's box of bones didn't come from a lion. They came from an extinct giant sloth. Prehistoric ground sloths first appeared around 35 million years ago. Dozens of species lived across North, Central and South America, alongside other ancient creatures like mastodons and giant armadillos. Some ground sloths, like the megalonychid, were cat-sized, but many were massive. Jefferson's sloth, Megalonyx, weighed about a ton, and that was small compared to megatherium, which could reach six metric tons, as much as an elephant. They ambled through the forests and savannas using their strong arms and sharp claws to uproot plants and climb trees, grazing on grasses, leaves, and prehistoric avocados. In fact, we might not have avocados today if not for the giant sloths. Smaller animals couldn't swallow the avocado's huge seed, but the sloths could, and they spread avocado trees far and wide. Ground sloths flourished for millions of years, but around 10,000 years ago, they started disappearing along with the Western Hemisphere's other giant mammals. Researchers think that ground sloths could have been pushed out by an oncoming ice age, or competition with other species, maybe humans, who arrived in the region around the time most of the sloths went extinct. Some of the smaller sloths did survive and migrated to the treetops. Today, there are six species left living in the rainforest canopies of Central and South America. Hanging out in the trees is a good way to avoid predators, and there are plenty of leaves to eat. But this diet has its drawbacks. Animals extract energy from food and use that energy to move around, maintain their body temperature, keep their organs working, and all the other activities necessary for survival. But leaves don't contain much energy, and that which they do have is tough to extract. Most herbivores supplement a leafy diet with higher energy foods like fruit and seeds. But sloths, especially three-toed sloths, rely on leaves almost exclusively. They've evolved finely tuned strategies for coping with this restricted diet. First, they extract as much energy from their food as possible. Sloths have a multi-chambered stomach that takes up a third of their body, and depending on the species, they can spend five to seven days, or even weeks, processing a meal. The other piece of the puzzle is to use as little energy as possible. One way sloths do this is, of course, by not moving very much. They spend most of their time eating, resting, or sleeping. They descend from the canopy just once a week for a bathroom break. When sloths do move, it's not very fast. It would take a sloth about five minutes to cross an average neighborhood street. This unhurried approach to life means that sloths don't need very much muscle. In fact, they have about 30% less muscle mass than other animals their size. Sloths also use less energy to keep themselves warm because their body temperature can fluctuate by about five degrees Celsius, less than a cold-blooded reptile, but more than most mammals. These physical and behavioral adaptations minimize the sloth's energy expenditure, or metabolic rate. Three-toed sloths have the slowest metabolism of any mammal. The giant panda is second slowest, and two-toed sloths come in third. Moving slowly has allowed sloths to thrive in their treetop habitat. But it's also made the sloths themselves a great habitat for other organisms, including algae, which provides a little extra camouflage, and maybe even a snack. Sloths may not be giant anymore, but that doesn't make them any less remarkable. |
Can you solve the pirate riddle? | null | TED-Ed | It's a good day to be a pirate. Amaro and his four mateys, Bart, Charlotte, Daniel, and Eliza have struck gold: a chest with 100 coins. But now, they must divvy up the booty according to the pirate code. As captain, Amaro gets to propose how to distribute the coins. Then, each pirate, including Amaro himself, gets to vote either yarr or nay. If the vote passes, or if there's a tie, the coins are divided according to plan. But if the majority votes nay, Amaro must walk the plank and Bart becomes captain. Then, Bart gets to propose a new distribution and all remaining pirates vote again. If his plan is rejected, he walks the plank, too, and Charlotte takes his place. This process repeats, with the captain's hat moving to Daniel and then Eliza until either a proposal is accepted or there's only one pirate left. Naturally, each pirate wants to stay alive while getting as much gold as possible. But being pirates, none of them trust each other, so they can't collaborate in advance. And being blood-thirsty pirates, if anyone thinks they'll end up with the same amount of gold either way, they'll vote to make the captain walk the plank just for fun. Finally, each pirate is excellent at logical deduction and knows that the others are, too. What distribution should Amaro propose to make sure he lives? Pause here if you want to figure it out for yourself! Answer in: 3 Answer in: 2 Answer in: 1 If we follow our intuition, it seems like Amaro should try to bribe the other pirates with most of the gold to increase the chances of his plan being accepted. But it turns out he can do much better than that. Why? Like we said, the pirates all know each other to be top-notch logicians. So when each votes, they won't just be thinking about the current proposal, but about all possible outcomes down the line. And because the rank order is known in advance, each can accurately predict how the others would vote in any situation and adjust their own votes accordingly. Because Eliza's last, she has the most outcomes to consider, so let's start by following her thought process. She'd reason this out by working backwards from the last possible scenario with only her and Daniel remaining. Daniel would obviously propose to keep all the gold and Eliza's one vote would not be enough to override him, so Eliza wants to avoid this situation at all costs. Now we move to the previous decision point with three pirates left and Charlotte making the proposal. Everyone knows that if she's outvoted, the decision moves to Daniel, who will then get all the gold while Eliza gets nothing. So to secure Eliza's vote, Charlotte only needs to offer her slightly more than nothing, one coin. Since this ensures her support, Charlotte doesn't need to offer Daniel anything at all. What if there are four pirates? As captain, Bart would still only need one other vote for his plan to pass. He knows that Daniel wouldn't want the decision to pass to Charlotte, so he would offer Daniel one coin for his support with nothing for Charlotte or Eliza. Now we're back at the initial vote with all five pirates standing. Having considered all the other scenarios, Amaro knows that if he goes overboard, the decision comes down to Bart, which would be bad news for Charlotte and Eliza. So he offers them one coin each, keeping 98 for himself. Bart and Daniel vote nay, but Charlotte and Eliza grudgingly vote yarr knowing that the alternative would be worse for them. The pirate game involves some interesting concepts from game theory. One is the concept of common knowledge where each person is aware of what the others know and uses this to predict their reasoning. And the final distribution is an example of a Nash equilibrium where each player knows every other players' strategy and chooses theirs accordingly. Even though it may lead to a worse outcome for everyone than cooperating would, no individual player can benefit by changing their strategy. So it looks like Amaro gets to keep most of the gold, and the other pirates might need to find better ways to use those impressive logic skills, like revising this absurd pirate code. |
How stress affects your body | null | TED-Ed | Cramming for a test? Trying to get more done than you have time to do? Stress is a feeling we all experience when we are challenged or overwhelmed. But more than just an emotion, stress is a hardwired physical response that travels throughout your entire body. In the short term, stress can be advantageous, but when activated too often or too long, your primitive fight or flight stress response not only changes your brain but also damages many of the other organs and cells throughout your body. Your adrenal gland releases the stress hormones cortisol, epinephrine, also known as adrenaline, and norepinephrine. As these hormones travel through your blood stream, they easily reach your blood vessels and heart. Adrenaline causes your heart to beat faster and raises your blood pressure, over time causing hypertension. Cortisol can also cause the endothelium, or inner lining of blood vessels, to not function normally. Scientists now know that this is an early step in triggering the process of atherosclerosis or cholesterol plaque build up in your arteries. Together, these changes increase your chances of a heart attack or stroke. When your brain senses stress, it activates your autonomic nervous system. Through this network of nerve connections, your big brain communicates stress to your enteric, or intestinal nervous system. Besides causing butterflies in your stomach, this brain-gut connection can disturb the natural rhythmic contractions that move food through your gut, leading to irritable bowel syndrome, and can increase your gut sensitivity to acid, making you more likely to feel heartburn. Via the gut's nervous system, stress can also change the composition and function of your gut bacteria, which may affect your digestive and overall health. Speaking of digestion, does chronic stress affect your waistline? Well, yes. Cortisol can increase your appetite. It tells your body to replenish your energy stores with energy dense foods and carbs, causing you to crave comfort foods. High levels of cortisol can also cause you to put on those extra calories as visceral or deep belly fat. This type of fat doesn't just make it harder to button your pants. It is an organ that actively releases hormones and immune system chemicals called cytokines that can increase your risk of developing chronic diseases, such as heart disease and insulin resistance. Meanwhile, stress hormones affect immune cells in a variety of ways. Initially, they help prepare to fight invaders and heal after injury, but chronic stress can dampen function of some immune cells, make you more susceptible to infections, and slow the rate you heal. Want to live a long life? You may have to curb your chronic stress. That's because it has even been associated with shortened telomeres, the shoelace tip ends of chromosomes that measure a cell's age. Telomeres cap chromosomes to allow DNA to get copied every time a cell divides without damaging the cell's genetic code, and they shorten with each cell division. When telomeres become too short, a cell can no longer divide and it dies. As if all that weren't enough, chronic stress has even more ways it can sabotage your health, including acne, hair loss, sexual dysfunction, headaches, muscle tension, difficulty concentrating, fatigue, and irritability. So, what does all this mean for you? Your life will always be filled with stressful situations. But what matters to your brain and entire body is how you respond to that stress. If you can view those situations as challenges you can control and master, rather than as threats that are insurmountable, you will perform better in the short run and stay healthy in the long run. |
Can you solve the control room riddle? | null | TED-Ed | As your country's top spy, you must infiltrate the headquarters of the evil syndicate, find the secret control panel, and deactivate their death ray. But all you have to go on is the following information picked up by your surveillance team. The headquarters is a massive pyramid with a single room at the top level, two rooms on the next, and so on. The control panel is hidden behind a painting on the highest floor that can satisfy the following conditions: Each room has exactly three doors to other rooms on that floor, except the control panel room, which connects to only one, there are no hallways, and you can ignore stairs. Unfortunately, you don't have a floor plan, and you'll only have enough time to search a single floor before the alarm system reactivates. Can you figure out which floor the control room is on? Pause now to solve the riddle yourself. Answer in: 3 Answer in: 2 Answer in: 1 To solve this problem, we need to visualize it. For starters, we know that on the correct floor there's one room, let's call it room A, with one door to the control panel room, plus one door to room B, and one to C. So there must be at least four rooms, which we can represent as circles, drawing lines between them for the doorways. But once we connect rooms B and C, there are no other connections possible, so the fourth floor down from the top is out. We know the control panel has to be as high up as possible, so let's make our way down the pyramid. The fifth highest floor doesn't work either. We can figure that out by drawing it, but to be sure we haven't missed any possibilities, here's another way. Every door corresponds to a line in our graph that makes two rooms into neighbors. So in the end, there have to be an even number of neighbors no matter how many connections we make. On the fifth highest floor, to fulfill our starting conditions, we'd need four rooms with three neighbors each, plus the control panel room with one neighbor, which makes 13 total neighbors. Since that's an odd number, it's not possible, and, in fact, this also rules out every floor that has an odd number of rooms. So let's go one more floor down. When we draw out the rooms, low and behold, we can find an arrangement that works like this. Incidentally, the study of such visual models that show the connections and relationships between different objects is known as graph theory. In a basic graph, the circles representing the objects are known as nodes, while the connecting lines are called edges. Researchers studying such graphs ask questions like, "How far is this node from that one?" "How many edges does the most popular node have?" "Is there a route between these two nodes, and if so, how long is it?" Graphs like this are often used to map communication networks, but they can represent almost any kind of network, from transport connections within a city and social relationships among people, to chemical interactions between proteins or the spread of an epidemic through different locations. So, armed with these techniques, back to the pyramid. You avoid the guards and security cameras, infiltrate the sixth floor from the top, find the hidden panel, pull some conspicuous levers, and send the death ray crashing into the ocean. Now, time to solve the mystery of why your surveillance team always gives you cryptic information. Hi everybody. If you liked this riddle, try solving these two. |
Light waves, visible and invisible | {0: 'Lucianne Walkowicz works on NASA\'s Kepler mission, studying starspots and "the tempestuous tantrums of stellar flares."'} | TED-Ed | What if you could only see one color? Imagine, for instance, that you could only see things that were red and that everything else was completely invisible to you. As it turns out, that's how you live your life all the time because your eyes can only see a minuscule part of the full spectrum of light. Different kinds of light are all around you everyday but are invisible to the human eye, from the radio waves that carry your favorite songs, to the x-rays doctors use to see inside of you, to the microwaves that heat up your food. In order to understand how these can all be light, we'll need to know a thing or two about what light is. Light is electromagnetic radiation that acts like both a wave and a particle. Light waves are kind of like waves on the ocean. There are big waves and small waves, waves that crash on the shore one right after the other, and waves that only roll in every so often. The size of a wave is called its wavelength, and how often it comes by is called its frequency. Imagine being a boat in that ocean, bobbing up and down as the waves go by. If the waves that day have long wavelengths, they'll make you bob only so often, or at a low frequency. If the waves, instead, have short wavelengths, they'll be close together, and you'll bob up and down much more often, at a high frequency. Different kinds of light are all waves, they just have different wavelengths and frequencies. If you know the wavelength or frequency of a wave of light, you can also figure out its energy. Long wavelengths have low energies, while short wavelengths have high energies. It's easy to remember if you think about being in that boat. If you were out sailing on a day with short, choppy waves, you'd probably be pretty high energy yourself, running around to keep things from falling over. But on a long wavelength sea, you'd be rolling along, relaxed, low energy. The energy of light tells us how it will interact with matter, for example, the cells of our eyes. When we see, it's because the energy of light stimulates a receptor in our eye called the retina. Our retina are only sensitive to light with a very small range in energy, and so we call that range of light visible light. Inside our retina are special receptors called rods and cones. The rods measure brightness, so we know how much light there is. The cones are in charge of what color of light we see because different cones are sensitive to different energies of light. Some cones are more excited by light that is long wavelength and low energy, and other cones are more excited by short wavelength, high-energy light. When light hits our eye, the relative amount of energy each cone measures signals our brain to perceive colors. The rainbow we perceive is actually visible light in order of its energy. At one side of the rainbow is low-energy light we see as red, and at the other side is high-energy light we see as blue. If light shines on us that has an energy our retina can't measure, we won't be able to see it. Light that is too short wavelength or high energy gets absorbed by the eye's surface before it can even get to the retina, and light that is too long wavelength doesn't have enough energy to stimulate our retina at all. The only thing that makes one kind of light different from another is its wavelength. Radio waves have long wavelengths, while x-rays have short wavelengths. And visible light, the kind you can actually see, is somewhere in between. Even though our eyes can't detect light outside of the visible range, we can build special detectors that are stimulated by these other wavelengths of light, kind of like digital eyes. With these devices, we can measure the light that is there, even though we can't see it ourselves. So, take a step back and think about all of this for a moment. Even though they seem different, the warmth you feel from a crackling fire is the same as the sun shining on you on a beautiful day, the same as ultraviolet light you put on sunscreen to protect yourself from, the same thing as your TV, your radio, and your microwave. Now, those examples are all things here on Earth, things you experience in your everyday life, but here's something even more amazing. Our universe gives off the full spectrum of light, too. When you think of the night sky, you probably think of being able to see the stars shining with your own eyes, but that's just visible light, which you now know is only a tiny part of the full spectrum. If we had to draw the universe and could only use visible light, it would be like having only one crayon — pretty sad. To see the universe in its full spectrum, we need to have the right eyes, and that means using special telescopes that can help us see beyond visible light. You've probably heard of the Hubble Space Telescope and seen its beautiful pictures taken in visible and ultraviolet light. But you might not know that there are 20 space telescopes in orbit, missions that can each see part of the full spectrum of light. With telescopes acting as our virtual eyes, both in space and here on Earth, we can see some amazing things. And the coolest thing of all, no matter the wavelength or energy, the light that we see out in the distant universe is the same thing as the light that we can experience and study here on Earth. So, since we know the physics of how x-ray, ultraviolet light, or microwaves work here, we can study the light of a distant star or galaxy and know what kinds of things are happening there too. So, as you go about your daily life, think beyond what your eyes can and can't see. Knowing just a little bit about the natural world can help you perceive the full spectrum around you all the time. |
Can you solve the unstoppable blob riddle? | null | TED-Ed | A shooting star crashes on Earth, and a hideous blob emerges. It creeps and leaps, it glides and slides. It’s also unstoppable: weapons, fire, extreme temperatures… no matter what you throw at it, it just regrows and continues its rampage. Its expansion is breathtaking; it doubles in size every hour. But there’s one opportunity: after each hour, it goes to sleep, forming itself into a flat triangle and resting for a few minutes before it begins eating and growing again. Your only chance to save the planet involves a satellite-mounted nano-fission ray that can cut through the blob. When the blog is active it heals itself within seconds. However, when you break the sleeping blob into two triangles, you make a critical discovery. The acute triangle portion, with all angles less than 90 degrees, is inert. It never “wakes up.” The obtuse triangle, which has an angle greater than 90 degrees, wakes up as usual and keeps growing. Similar experiments show that all shapes other than acute triangles, including right triangles, will also wake up. For the next few minutes, the blob is sleeping in its obtuse triangle form. You can make clean, straight-line cuts between any two points on or inside the triangle. But you’ll only have time to make 7 cuts while the satellite is above you. By the time it completes its orbit and returns, the blob will have consumed the entire world, if even a single portion that will wake up remains. How can you cut the blob entirely into acute triangles and stop it from destroying the planet? Pause the video now to figure out for yourself Answer in 3 Answer in 2 Answer in 1 While this seems doable at first, there’s a hidden difficulty when it comes to avoiding obtuse and right angles. Every time you make a cut that reaches an edge, it either makes an acute and an obtuse angle, or two right angles. That makes it seems like you’re doomed to keep creating obtuse angles. But as with so many of life’s problems, we can look to pizza for inspiration. Imagine squaring off the outside of a pizza, so that instead of a circle, it’s an octagon. When we cut it into slices, each of the eight triangles is acute. This works with larger polygons too. Importantly, it also works for some polygons with fewer sides, including heptagons, hexagons, and pentagons. That’s good news, because if you cut off the sharp corners of the blob triangle, a pentagon is exactly what you’ll be left with. And just like a pizza, you can cut the blob pentagon into five acute triangles. That’s 7 cuts, and it renders the blob completely inert. You’ve saved the day! Now you just need to figure out what to do with all of these giant, practically indestructible triangles. |
The secret to scientific discoveries? Making mistakes | {0: 'Phil Plait has spent his life evangelizing science, getting the word out about the real world and how we know what we know about it.'} | TEDxBoulder | Now, people have a lot of misconceptions about science — about how it works and what it is. A big one is that science is just a big old pile of facts. But that's not true — that's not even the goal of science. Science is a process. It's a way of thinking. Gathering facts is just a piece of it, but it's not the goal. The ultimate goal of science is to understand objective reality the best way we know how, and that's based on evidence. The problem here is that people are flawed. We can be fooled — we're really good at fooling ourselves. And so baked into this process is a way of minimizing our own bias. So sort of boiled down more than is probably useful, here's how this works. If you want to do some science, what you want to do is you want to observe something ... say, "The sky is blue. Hey, I wonder why?" You question it. The next thing you do is you come up with an idea that may explain it: a hypothesis. Well, you know what? Oceans are blue. Maybe the sky is reflecting the colors from the ocean. Great, but now you have to test it so you predict what that might mean. Your prediction would be, "Well, if the sky is reflecting the ocean color, it will be bluer on the coasts than it will be in the middle of the country." OK, that's fair enough, but you've got to test that prediction so you get on a plane, you leave Denver on a nice gray day, you fly to LA, you look up and the sky is gloriously blue. Hooray, your thesis is proven. But is it really? No. You've made one observation. You need to think about your hypothesis, think about how to test it and do more than just one. Maybe you could go to a different part of the country or a different part of the year and see what the weather's like then. Another good idea is to talk to other people. They have different ideas, different perspectives, and they can help you. This is what we call peer review. And in fact that will probably also save you a lot of money and a lot of time, flying coast-to-coast just to check the weather. Now, what happens if your hypothesis does a decent job but not a perfect job? Well, that's OK, because what you can do is you can modify it a little bit and then go through this whole process again — make predictions, test them — and as you do that over and over again, you will hone this idea. And if it gets good enough, it may be accepted by the scientific community, at least provisionally, as a good explanation of what's going on, at least until a better idea or some contradictory evidence comes along. Now, part of this process is admitting when you're wrong. And that can be really, really hard. Science has its strengths and weaknesses and they depend on this. One of the strengths of science is that it's done by people, and it's proven itself to do a really good job. We understand the universe pretty well because of science. One of science's weaknesses is that it's done by people, and we bring a lot of baggage along with us when we investigate things. We are egotistical, we are stubborn, we're superstitious, we're tribal, we're humans — these are all human traits and scientists are humans. And so we have to be aware of that when we're studying science and when we're trying to develop our theses. But part of this whole thing, part of this scientific process, part of the scientific method, is admitting when you're wrong. I know, I've been there. Many years ago I was working on Hubble Space Telescope, and a scientist I worked with came to me with some data, and he said, "I think there may be a picture of a planet orbiting another star in this data." We had not had any pictures taken of planets orbiting other stars yet, so if this were true, then this would be the first one and we would be the ones who found it. That's a big deal. I was very excited, so I just dug right into this data. I spent a long time trying to figure out if this thing were a planet or not. The problem is planets are faint and stars are bright, so trying to get the signal out of this data was like trying to hear a whisper in a heavy metal concert — it was really hard. I tried everything I could, but after a month of working on this, I came to a realization ... couldn't do it. I had to give up. And I had to tell this other scientist, "The data's too messy. We can't say whether this is a planet or not." And that was hard. Then later on we got follow-up observations with Hubble, and it showed that it wasn't a planet. It was a background star or galaxy, something like that. Well, not to get too technical, but that sucked. (Laughter) I was really unhappy about this. But that's part of it. You have to say, "Look, you know, we can't do this with the data we have." And then I had to face up to the fact that even the follow-up data showed we were wrong. Emotionally I was pretty unhappy. But if a scientist is doing their job correctly, being wrong is not so bad because that means there's still more stuff out there — more things to figure out. Scientists don't love being wrong but we love puzzles, and the universe is the biggest puzzle of them all. Now having said that, if you have a piece and it doesn't fit no matter how you move it, jamming it in harder isn't going to help. There's going to be a time when you have to let go of your idea if you want to understand the bigger picture. The price of doing science is admitting when you're wrong, but the payoff is the best there is: knowledge and understanding. And I can give you a thousand examples of this in science, but there's one I really like. It has to do with astronomy, and it was a question that had been plaguing astronomers literally for centuries. When you look at the Sun, it seems special. It is the brightest object in the sky, but having studied astronomy, physics, chemistry, thermodynamics for centuries, we learned something very important about it. It's not that special. It's a star just like millions of other stars. But that raises an interesting question. If the Sun is a star and the Sun has planets, do these other stars have planets? Well, like I said with my own failure in the "planet" I was looking for, finding them is super hard, but scientists tend to be pretty clever people and they used a lot of different techniques and started observing stars. And over the decades they started finding some things that were pretty interesting, right on the thin, hairy edge of what they were able to detect. But time and again, it was shown to be wrong. That all changed in 1991. A couple of astronomers — Alexander Lyne — Andrew Lyne, pardon me — and Matthew Bailes, had a huge announcement. They had found a planet orbiting another star. And not just any star, but a pulsar, and this is the remnant of a star that has previously exploded. It's blasting out radiation. This is the last place in the universe you would expect to find a planet, but they had very methodically looked at this pulsar, and they detected the gravitational tug of this planet as it orbited the pulsar. It looked really good. The first planet orbiting another star had been found ... except not so much. (Laughter) After they made the announcement, a bunch of other astronomers commented on it, and so they went back and looked at their data and realized they had made a very embarrassing mistake. They had not accounted for some very subtle characteristics of the Earth's motion around the Sun, which affected how they measured this planet going around the pulsar. And it turns out that when they did account for it correctly, poof — their planet disappeared. It wasn't real. So Andrew Lyne had a very formidable task. He had to admit this. So in 1992 at the American Astronomical Society meeting, which is one of the largest gatherings of astronomers on the planet, he stood up and announced that he had made a mistake and that the planet did not exist. And what happened next — oh, I love this — what happened next was wonderful. He got an ovation. The astronomers weren't angry at him; they didn't want to chastise him. They praised him for his honesty and his integrity. I love that! Scientists are people. (Laughter) And it gets better! (Laughter) Lyne steps off the podium. The next guy to come up is a man named Aleksander Wolszczan He takes the microphone and says, "Yeah, so Lyne's team didn't find a pulsar planet, but my team found not just one but two planets orbiting a different pulsar. We knew about the problem that Lyne had, we checked for it, and yeah, ours are real." And it turns out he was right. And in fact, a few months later, they found a third planet orbiting this pulsar and it was the first exoplanet system ever found — what we call alien worlds — exoplanets. That to me is just wonderful. At that point the floodgates were opened. In 1995 a planet was found around a star more like the Sun, and then we found another and another. This is an image of an actual planet orbiting an actual star. We kept getting better at it. We started finding them by the bucketload. We started finding thousands of them. We built observatories specifically designed to look for them. And now we know of thousands of them. We even know of planetary systems. That is actual data, animated, showing four planets orbiting another star. This is incredible. Think about that. For all of human history, you could count all the known planets in the universe on two hands — nine — eight? Nine? Eight — eight. (Laughter) Eh. (Laughter) But now we know they're everywhere. Every star — for every star you see in the sky there could be three, five, ten planets. The sky is filled with them. We think that planets may outnumber stars in the galaxy. This is a profound statement, and it was made because of science. And it wasn't made just because of science and the observatories and the data; it was made because of the scientists who built the observatories, who took the data, who made the mistakes and admitted them and then let other scientists build on their mistakes so that they could do what they do and figure out where our place is in the universe. That is how you find the truth. Science is at its best when it dares to be human. Thank you. (Applause and cheers) |
Why I turned Chicago's abandoned homes into art | {0: 'Amanda Williams blurs the distinction between art and architecture through works that employ color as a way to draw attention to the political complexities of race, place and value in cities.'} | TEDWomen 2018 | I really love color. I notice it everywhere and in everything. My family makes fun of me because I like to use colors with elusive-sounding names, like celadon ... (Laughter) ecru ... carmine. Now, if you haven't noticed, I am black, thank you — (Laughter) and when you grow up in a segregated city as I have, like Chicago, you're conditioned to believe that color and race can never be separate. There's hardly a day that goes by that somebody is not reminding you of your color. Racism is my city's vivid hue. Now, we can all agree that race is a socially constructed phenomenon, but it's often hard to see it in our everyday existence. Its pervasiveness is everywhere. The neighborhoods I grew up in were filled with a kind of culturally coded beauty. Major commercial corridors were lined with brightly painted storefronts that competed for black consumer dollars. The visual mash-ups of corner stores and beauty supply houses, currency exchanges, are where I actually, inadvertently learned the foundational principles of something I would later come to know is called color theory. I can remember being pretty intimidated by this term in college — color theory. All these stuffy old white guys with their treatises and obscure terminologies. I'd mastered each one of their color palettes and associated principles. Color theory essentially boils down to the art and science of using color to form compositions and spaces. It's not so complicated. This was my bible in college. Josef Albers posited a theory about the color red, and it always has stuck with me. He argues that the iconic color of a cola can is red, and that in fact all of us can agree that it's red but the kinds of reds that we imagine are as varied as the number of people in this room. So imagine that. This color that we've all been taught since kindergarten is primary — red, yellow, blue — in fact is not primary, is not irreducible, is not objective but quite subjective. What? (Laughter) Albers called this "relational." Relational. And so it was the first time that I was able to see my own neighborhood as a relational context. Each color is affected by its neighbor. Each other is affected by its neighbor. In the 1930s, the United States government created the Federal Housing Administration, which in turn created a series of maps which were using a color-coding system to determine which neighborhoods should and should not receive federal housing loans. Their residential security map was its own kind of color palette, and in fact was more influential than all of those color palettes that I had been studying in college combined. Banks would not lend to people who lived in neighborhoods like mine. That's me in D86. Their cartographers were literally coloring in these maps and labeling that color "hazardous." Red was the new black, and black neighborhoods were colored. The problem persists today, and we've seen it most recently in the foreclosure crisis. In Chicago, this is best symbolized by these Xs that are emblazoned on the fronts of vacated houses on the South and West Side. The reality is that someone else's color palettes were determining my physical and artistic existence. Ridiculous. I decided that I'd create my own color palette and speak to the people who live where I do and alter the way that color had been defined for us. It was a palette that I didn't have to search far for and look for in a treatise, because I already knew it. What kind of painter emerges from this reality? What color is urban? What color is ghetto? What color is privilege? What color is gang-related? What color is gentrification? What color is Freddie Gray? What color is Mike Brown? Finally, I'd found a way to connect my racialized understanding of color with my theoretical understanding of color. And I gave birth to my third baby: "Color(ed) Theory." (Laughter) "Color(ed) Theory" was a two-year artistic project in which I applied my own color palette to my own neighborhoods in my own way. Now, if I walked down 79th Street right now and I asked 50 people for the name of the slightly greener shade of cyan, they would look at me sideways. (Laughter) But if I say, "What color is Ultra Sheen?" — oh, a smile emerges, stories about their grandmother's bathroom ensue. I mean, who needs turquoise when you have Ultra Sheen? Who needs teal when you have Ultra Sheen? Who needs ultramarine when you have ... (Audience) Ultra Sheen. (Laughter) This is exactly how I derived my palette. I would ask friends and family and people with backgrounds that were similar to mine for those stories and memories. The stories weren't always happy but the colors always resonated more than the product itself. I took those theories to the street. "Ultra Sheen." "Pink Oil Moisturizer." If you're from Chicago, "Harold's Chicken Shack." (Laughter) "Currency Exchange + Safe Passage." "Flamin' Red Hots." "Loose Squares" ... and "Crown Royal Bag." I painted soon-to-be-demolished homes in a much-maligned area called Englewood. We'd gather up as much paint as I could fit in my trunk, I'd call my most trusted art homies, my amazing husband always by my side, and we'd paint every inch of the exteriors in monochromatic fashion. I wanted to understand scale in a way that I hadn't before. I wanted to apply the colors to the biggest canvas I could imagine ... houses. So I'd obsessively drive up and down familiar streets that I'd grown up on, I'd cross-reference these houses with the city's data portal to make sure that they'd been tagged for demolition — unsalvageable, left for dead. I really wanted to understand what it meant to just let color rule, to trust my instincts, to stop asking for permission. No meetings with city officials, no community buy-in, just let color rule in my desire to paint different pictures about the South Side. These houses sit in stark contrast to their fully lined counterparts. We'd paint to make them stand out like Monopoly pieces in these environments. And we'd go on these early Sunday mornings and keep going until we ran out of that paint or until someone complained. "Hey, did you paint that?" a driver asked as I was taking this image one day. Me, nervously: "Yes?" His face changed. "Aw, I thought Prince was coming." (Laughter) He had grown up on this block, and so you could imagine when he drove past and saw one of its last remaining houses mysteriously change colors overnight, it was clearly not a Crown Royal bag involved, it was a secret beacon from Prince. (Laughter) And though that block was almost all but erased, it was the idea that Prince could pop up in unexpected places and give free concerts in areas that the music industry and society had deemed were not valuable anymore. For him, the idea that just the image of this house was enough to bring Prince there meant that it was possible. In that moment, that little patch of Eggleston had become synonymous with royalty. And for however briefly, Eric Bennett's neighborhood had regained its value. So we traded stories despite being strangers about which high school we'd gone to and where we'd grown up, and Mrs. So-and-so's candy store — of being kids on the South Side. And once I revealed that in fact this project had absolutely nothing to do with Prince, Eric nodded in seeming agreement, and as we parted ways and he drove off, he said, "But he could still come!" (Laughter) He had assumed full ownership of this project and was not willing to relinquish it, even to me, its author. That, for me, was success. I wish I could tell you that this project transformed the neighborhood and all the indices that we like to rely on: increased jobs, reduced crime, no alcoholism — but in fact it's more gray than that. "Color(ed) Theory" catalyzed new conversations about the value of blackness. "Color(ed) Theory" made unmistakably visible the uncomfortable questions that institutions and governments have to ask themselves about why they do what they do. They ask equally difficult questions of myself and my neighborhood counterparts about our value systems and what our path to collective agency needs to be. Color gave me freedom in a way that didn't wait for permission or affirmation or inclusion. Color was something that I could rule now. One of the neighborhood members and paint crew members said it best when he said, "This didn't change the neighborhood, it changed people's perceptions about what's possible for their neighborhood," in big and small ways. Passersby would ask me, "Why are you painting that house when you know the city's just going to come and tear it down?" At the time, I had no idea, I just knew that I had to do something. I would give anything to better understand color as both a medium and as an inescapable way that I am identified in society. If I have any hope of making the world better, I have to love and leverage both of these ways that I'm understood, and therein lies the value and the hue. Thank you. (Applause and cheers) |
Why do hospitals have particle accelerators? | null | TED-Ed | This syringe contains a radioactive form of glucose known as FDG. The doctor will soon inject its contents into her patient’s arm, whom she’s testing for cancer using a PET scanner. The FDG will quickly circulate through his body. If he has a tumor, cancer cells within it will take up a significant portion of the FDG, which will act as a beacon for the scanner. PET tracers such as FDG are among the most remarkable tools in medical diagnostics, and their life begins in a particle accelerator, just hours earlier. The particle accelerator in question is called a cyclotron, and it’s often housed in a bunker within hospitals. It uses electromagnetic fields to propel charged particles like protons faster and faster along a spiraling path. When the protons reach their maximum speed, they shoot out onto a target that contains a few milliliters of a type of water with a heavy form of oxygen called oxygen-18. When a proton slams into one of these heavier oxygen atoms, it kicks out another subatomic particle called a neutron. This impact turns oxygen-18 into fluorine-18, a radioactive isotope that can be detected on a PET scan. In a little under two hours, about half the fluorine will be gone due to radioactive decay, so the clock is ticking to get the scan done. So how can fluorine-18 be used to detect diseases? Radiochemists at the hospital can use a series of chemical reactions to attach the radioactive fluorine to different molecules, creating radiotracers. The identity of the tracer depends on what doctors want to observe. FDG is a common one because the rate at which cells consume glucose can signal the presence of cancer; the location of an infection; or the slowing brain function of dementia. The FDG is now ready for the patient’s scan. When a radiolabeled tracer enters the body, it travels through the circulatory system and gets taken up by its target— whether that's a protein in the brain, cancer cells, or otherwise. Within a few minutes, a significant amount of the tracer has found its way to the target area and the rest has cleared from circulation. Now the doctors can see their target using a PET, or positron emission tomography, scanner. The radiation that the tracer emits is what makes this possible. The isotopes used in PET decay by positron emission. Positrons are essentially electrons with positive charge. When emitted, a positron collides with an electron from another molecule in its surroundings. This causes a tiny nuclear reaction in which the mass of the two particles is converted into two high-energy photons, similar to X-rays, that shoot out in opposite directions. These photons will then impact an array of paired radiation detectors in the scanner walls. The software in the scanner uses those detectors to estimate where inside the body the collision occurred and create a 3D map of the tracer’s distribution. PET scans can detect the spread of cancer before it can be spotted with other types of imaging. They’re also revolutionizing the diagnosis of Alzheimer’s disease by allowing doctors to see amyloid, the telltale protein buildup that otherwise couldn’t be confirmed without an autopsy. Meanwhile, researchers are actively working to develop new tracers and expand the possibilities of what PET scans can be used for. But with all this talk of radiation and nuclear reactions inside the body, are these scans safe? Even though no amount of ionizing radiation is completely safe, the amount of radiation the body receives during a PET scan is actually quite low. One scan is comparable to what you’re exposed to over two or three years from natural radioactive sources, like radon gas; or the amount a pilot would rack up from cosmic radiation after 20 to 30 transatlantic flights. Most patients feel that those risks are acceptable for the chance to diagnose and treat their illnesses. |
How you can help save the bees, one hive at a time | {0: "Noah Wilson-Rich doesn't just want to know why bees are dying off, but what's saving them."} | TEDxProvincetown | Pollinator decline is a grand challenge in the modern world. Of the 200,000 species of pollinators, honeybees are the most well-understood, partly because of our long history with them dating back 8,000 years ago to our cave drawings in what is now modern-day Spain. And yet we know that this indicator species is dying off. Last year alone, we lost 40 percent of all beehives in the United States. That number is even higher in areas with harsh winters, like here in Massachusetts, where we lost 47 percent of beehives in one year alone. Can you imagine if we lost half of our people last year? And if those were the food-producing people? It's untenable. And I predict that in 10 years, we will lose our bees. If not for the work of beekeepers replacing these dead beehives, we would be without foods that we rely upon: fruits, vegetables, crunchy almonds and nuts, tart apples, sour lemons. Even the food that our cattle rely upon to eat, hay and alfalfa — gone, causing global hunger, economic collapse, a total moral crisis across earth. Now, I first started keeping bees here in Cape Cod right after I finished my doctorate in honeybee immunology. (Laughter) (Applause) Imagine getting such a degree in a good economy — and it was 2009: the Great Recession. And I was onto something. I knew that I could find out how to improve bee health. And so the community on Cape Cod here in Provincetown was ripe for citizen science, people looking for ways to get involved and to help. And so we met with people in coffee shops. A wonderful woman named Natalie got eight beehives at her home in Truro, and she introduced us to her friend Valerie, who let us set up 60 beehives at an abandoned tennis court on her property. And so we started testing vaccines for bees. We were starting to look at probiotics. We called it "bee yogurt" — ways to make bees healthier. And our citizen science project started to take off. Meanwhile, back in my apartment here, I was a bit nervous about my landlord. I figured I should tell him what we were doing. (Laughter) I was terrified; I really thought I was going to get an eviction notice, which really was the last thing we needed, right? I must have caught him on a good day, though, because when I told him what we were doing and how we started our nonprofit urban beekeeping laboratory, he said, "That's great! Let's get a beehive in the back alley." I was shocked. I was completely surprised. I mean, instead of getting an eviction notice, we got another data point. And in the back alley of this image, what you see here, this hidden beehive — that beehive produced more honey that first year than we have ever experienced in any beehive we had managed. It shifted our research perspective forever. It changed our research question away from "How do we save the dead and dying bees?" to "Where are bees doing best?" And we started to be able to put maps together, looking at all of these citizen science beehives from people who had beehives at home decks, gardens, business rooftops. We started to engage the public, and the more people who got these little data points, the more accurate our maps became. And so when you're sitting here thinking, "How can I get involved?" you might think about a story of my friend Fred, who's a commercial real estate developer. He was thinking the same thing. He was at a meeting, thinking about what he could do for tenant relations and sustainability at scale. And while he was having a tea break, he put honey into his tea and noticed on the honey jar a message about corporate sustainability from the host company of that meeting. And it sparked an idea. He came back to his office. An email, a phone call later, and — boom! — we went national together. We put dozens of beehives on the rooftops of their skyscrapers across nine cities nationwide. Nine years later — (Applause) Nine years later, we have raised over a million dollars for bee research. We have a thousand beehives as little data points across the country, 18 states and counting, where we have created paying jobs for local beekeepers, 65 of them, to manage beehives in their own communities, to connect with people, everyday people, who are now data points together making a difference. So in order to explain what's actually been saving bees, where they're thriving, I need to first tell you what's been killing them. The top three killers of bees are agricultural chemicals such as pesticides, herbicides, fungicides; diseases of bees, of which there are many; and habitat loss. So what we did is we looked on our maps and we identified areas where bees were thriving. This was mostly in cities, we found. Data are now showing that urban beehives produce more honey than rural beehives and suburban beehives. Urban beehives have a longer life span than rural and suburban beehives, and bees in the city are more biodiverse; there are more bee species in urban areas. (Laughter) Right? Why is this? That was our question. So we started with these three killers of bees, and we flipped it: Which of these is different in the cities? So the first one, pesticides. We partnered up with the Harvard School of Public Health. We shared our data with them. We collected samples from our citizen science beehives at people's homes and business rooftops. We looked at pesticide levels. We thought there would be less pesticides in areas where bees are doing better. That's not the case. So what we found here in our study is — the orange bars are Boston, and we thought those bars would be the lowest, there would be the lowest levels of pesticides. And, in fact, there are the most pesticides in cities. So the pesticide hypothesis for what's saving bees — less pesticides in cities — is not it. And this is very typical of my life as a scientist. Anytime I've had a hypothesis, not only is it not supported, but the opposite is true. (Laughter) Which is still an interesting finding, right? We moved on. The disease hypothesis. We looked at diseases all over our beehives. And what we found in a similar study to this one with North Carolina State is: there's no difference between disease in bees in urban, suburban and rural areas. Diseases are everywhere; bees are sick and dying. In fact, there were more diseases of bees in cities. This was from Raleigh, North Carolina. So again, my hypothesis was not supported. The opposite was true. We're moving on. (Laughter) The habitat hypothesis. This said that areas where bees are thriving have a better habitat — more flowers, right? But we didn't know how to test this. So I had a really interesting meeting. An idea sparked with my friend and colleague Anne Madden, fellow TED speaker. We thought about genomics, kind of like AncestryDNA or 23andMe. Have you done these? You spit in a tube and you find out, "I'm German!" (Laughter) Well, we developed this for honey. So we have a sample of honey and we look at all the plant DNA, and we find out, "I'm sumac!" (Laughter) And that's what we found here in Provincetown. So for the first time ever, I'm able to report to you what type of honey is from right here in our own community. HoneyDNA, a genomics test. Spring honey in Provincetown is from privet. What's privet? Hedges. What's the message? Don't trim your hedges to save the bees. (Laughter) I know we're getting crunchy and it's controversial, so before you throw your tomatoes, we'll move to the summer honey, which is water lily honey. If you have honey from Provincetown right here in the summer, you're eating water lily juice; in the fall, sumac honey. We're learning about our food for the first time ever. And now we're able to report, if you need to do any city planning: What are good things to plant? What do we know the bees are going to that's good for your garden? For the first time ever for any community, we now know this answer. What's more interesting for us is deeper in the data. So, if you're from the Caribbean and you want to explore your heritage, Bahamian honey is from the laurel family, cinnamon and avocado flavors. But what's more interesting is 85 different plant species in one teaspoon of honey. That's the measure we want, the big data. Indian honey: that is oak. Every sample we've tested from India is oak, and that's 172 different flavors in one taste of Indian honey. Provincetown honey goes from 116 plants in the spring to over 200 plants in the summer. These are the numbers that we need to test the habitat hypothesis. In another citizen science approach, you find out about your food and we get some interesting data. We're finding out now that in rural areas, there are 150 plants on average in a sample of honey. That's a measure for rural. Suburban areas, what might you think? Do they have less or more plants in suburban areas with lawns that look nice for people but they're terrible for pollinators? Suburbs have very low plant diversity, so if you have a beautiful lawn, good for you, but you can do more. You can have a patch of your lawn that's a wildflower meadow to diversify your habitat, to improve pollinator health. Anybody can do this. Urban areas have the most habitat, best habitat, as you can see here: over 200 different plants. We have, for the first time ever, support for the habitat hypothesis. We also now know how we can work with cities. The City of Boston has eight times better habitat than its nearby suburbs. And so when we work with governments, we can scale this. You might think on my tombstone, it'll say, "Here lies Noah. Plant a flower." Right? I mean — it's exhausting after all of this. But when we scale together, when we go to governments and city planners — like in Boston, the honey is mostly linden trees, and we say, "If a dead tree needs to be replaced, consider linden." When we take this information to governments, we can do amazing things. This is a rooftop from Fred's company. We can plant those things on top of rooftops worldwide to start restoring habitat and securing food systems. We've worked with the World Bank and the presidential delegation from the country of Haiti. We've worked with wonderful graduate students at Yale University and Ethiopia. In these countries, we can add value to their honey by identifying what it is, but informing the people of what to plant to restore their habitat and secure their food systems. But what I think is even more important is when we think about natural disasters. For the first time, we now know how we can have a baseline measure of any habitat before it might be destroyed. Think about your hometown. What risks does the environment pose to it? This is how we're going to save Puerto Rico after Hurricane Maria. We now have a baseline measure of honey, honey DNA from before and after the storm. We started in Humacao. This is right where Hurricane Maria made landfall. And we know what plants to replace and in what quantity and where by triangulating honey DNA samples. You might even think about right here, the beautiful land that connected us, that primed us, all the citizen science to begin with, the erosion, the winter storms that are getting more violent every year. What are we going to do about this, our precious land? Well, looking at honey DNA, we can see what plants are good for pollinators that have deep roots, that can secure the land, and together, everybody can participate. And the solution fits in a teaspoon. If your hometown might get swept away or destroyed by a natural disaster, we now have a blueprint suspended in time for how to restore that on Earth, or perhaps even in a greenhouse on Mars. I know it sounds crazy, but think about this: a new Provincetown, a new hometown, a place that might be familiar that's also good for pollinators for a stable food system, when we're thinking about the future. Now, together, we know what's saving bees — by planting diverse habitat. Now, together, we know how bees are going to save us — by being barometers for environmental health, by being blueprints, sources of information, little data factories suspended in time. Thank you. (Applause) |
The wicked wit of Jane Austen | null | TED-Ed | Whether she’s describing bickering families, quiet declarations of love, or juicy gossip, Jane Austen’s writing often feels as though it was written just for you. Her dry wit and cheeky playfulness informs her heroines, whose conversational tone welcomes readers with a conspiratorial wink. It’s even been said that some readers feel like the author’s secret confidante, trading letters with their delightfully wicked friend Jane. But this unique brand of tongue-in-cheek humor is just one of the many feats found in her sly satires of society, civility, and sweeping romance. Written in the early nineteenth century, Austen's novels decode the sheltered lives of the upper classes in rural England. From resentment couched in pleasantries to arguing that masks attraction, her work explores the bewildering collision of emotions and etiquette. But while romance is a common thread in her work, Austen dismissed the sentimental style of writing so popular at the time. Instead of lofty love stories, her characters act naturally, and often awkwardly. They trade pragmatic advice, friendly jokes and not-so-friendly barbs about their arrogant peers. As they grapple with the endless rules of their society, Austen’s characters can usually find humor in all the hypocrisy, propriety, and small talk. As Mr. Bennet jokes to his favorite daughter, “For what do we live, but to make sport for our neighbors and laugh at them in our turn?” And though her heroines might ridicule senseless social mores, Austen fully understood the practical importance of maintaining appearances. At the time she was writing, a wealthy marriage was a financial necessity for most young women, and she often explores the tension between the mythical quest for love, and the economic benefits of making a match. The savvy socialite Mary Crawford sums this up in "Mansfield Park;" “I would have everybody marry if they can do it properly: I do not like to have people throw themselves away.” Unsurprisingly, these themes were also present in Austen’s personal life. Born in 1775, she lived in the social circles found in her novels. Jane's parents supported her education, and provided space for her to write and publish her work anonymously. But writing was hardly lucrative work. And although she had sparks of chemistry, she never married. Elements of her circumstances can be found in many of her characters; often intelligent women with witty, pragmatic personalities, and rich inner lives. These headstrong heroines provide an entertaining anchor for their tumultuous romantic narratives. Like the irreverent Elizabeth Bennet of "Pride and Prejudice," whose devotion to her sisters’ love lives blinds her to a clumsy suitor. Or the iron-willed Anne Elliot of "Persuasion," who chooses to remain unmarried after the disappearance of her first love. And Elinor Dashwood, who fiercely protects her family at the cost of her own desires in "Sense and Sensibility." These women all encounter difficult choices about romantic, filial, and financial stability, and they resolve them without sacrificing their values– or their sense of humor. Of course, these characters are far from perfect. They often think they have all the answers. And by telling the story from their perspective, Austen tricks the viewer into believing their heroine knows best– only to pull the rug out from under the protagonist and the reader. In "Emma," the titular character feels surrounded by dull neighbors, and friends who can’t hope to match her wit. As her guests prattle on and on about nothing, the reader begins to agree– Emma is the only exciting character in this quiet neighborhood. Yet despite her swelling ego, Emma may not be as in control as she thinks – in life or love. And Austen’s intimate use of perspective makes these revelations doubly surprising, blindsiding both Emma and her audience. But rather than diminishing her host of heroines, these flaws only confirm “the inconsistency of all human characters.” Their complexity has kept Austen prominent on stage and screen, and made her work easily adaptable for modern sensibilities. So hopefully, new readers will continue to find a friend in Ms. Austen for many years to come. |
Creative ways to get kids to thrive in school | {0: 'Olympia Della Flora wants schools to think differently about educating students -- by helping them manage their emotions.'} | TED Salon: Education Everywhere | This is an elementary school in Columbus, Ohio. And inside of this school there was a student named D. When D started school here he was six years old: cute as a button, with a smile that brightened the entire room. But after a few months in school, D became angry, and that smile faded. D began to do things like flip tables, throw desks and chairs, yell at teachers, stand in windowsills, run in and out of the classroom and even running out of the school. Sometimes these fits of anger would put the entire school into lockdown mode until D could get himself back together, which could sometimes take over an hour. No one in the school knew how to help D. I know this because I was the principal at this school. And what I quickly and collectively learned with my staff was that this situation was more extreme than anything we had ever been trained for. Every time that D lashed out, I kept thinking to myself: what did I miss during my principal prep coursework? What am I supposed to do with a kid like D? And how am I going to stop him from impeding the learning of all the other students? And yet after we did everything that we thought we knew, such as talking to D and taking away privileges and parent phone calls home, the only real option we had left to do was to kick him out, and I knew that would not help him. This scenario is not unique to D. Students all over the world are struggling with their education. And though we didn't come up with a fail-safe solution, we did come up with a simple idea: that in order for kids like D to not only survive in school but to thrive, we somehow had to figure out a way to not only teach them how to read and write but also how to help them deal with and manage their own emotions. And in doing that, we were able to move our school from one of the lowest-performing schools in the state of Ohio, with an F rating, all the way up to a C in just a matter of a few years. So it might sound obvious, right? Of course teachers should be focused on the emotional well-being of their kids. But in reality, when you're in a classroom full of 30 students and one of them's throwing tables at you, it's far easier to exclude that child than to figure out what's going on inside of his head. But what we learned about D, and for kids like D, was that small changes can make huge differences, and it's possible to start right now. You don't need bigger budgets or grand strategic plans, you simply need smarter ways of thinking about what you have and where you have it. In education, we tend to always look outside the box for answers, and we rarely spend enough time, money and effort developing what we already have inside the box. And this is how meaningful change can happen fast. So here's what I learned about D. I was wanting to dig a little bit deeper to figure out how he had become so angry. And what I learned was his father had left the home and his mother was working long shifts in order to support the family, which left no adult for D to connect with — and he was in charge of taking care of his younger brother when he got home from school. Might I remind you that D was six years old? Can't say that I blame him for having some trouble transitioning into the school environment. But yet we had to figure out a way to help him with these big emotions all while teaching him core skills of reading and math. And three things helped us most. First, we had to figure out where he was struggling the most. And like most young kids, arrival at school can be a tough transition time as they're moving from a less structured home environment to a more structured school environment. So what we did for D was we created a calming area for him in our time-out room, which we had equipped with rocking chairs and soft cushions and books, and we allowed D to go to this place in the morning, away from the other kids, allowing him time to transition back into the school environment on his own terms. And as we began to learn more about D, we learned other strategies that helped him calm down. For example, D loved to help younger students, so we made him a kindergarten helper, and he went into the kindergarten classroom and taught students how to write their letters. And he was actually successful with a few of them that the teacher was unable to reach. And believe it or not, D actually helped calm some of those kindergarten students down, signalling to us that the influence of peers on behavior was far greater than anything we adults could ever do. We used humor and song with him. Yes, I know it sounds really silly that the principal and the teachers would actually laugh with kids, but you can imagine the shock on D's face when the principal's cracking a joke or singing a song from the radio station, which almost always ended in a laugh, shortening the length of his outburst and helping us to connect with him in his world. So I know some you are like, "It's really not practical to lay on this kind of special treatment for every student," but we actually made it happen. Because once we figured out the tools and tactics that worked for D, our teachers were able to roll that out and use them with other students. We began to proactively address student behavior instead of simply react to it. Our teachers actually took time during the lesson plan to teach kids how to identify their feelings and appropriate, healthy coping strategies for dealing with them, such as counting to 10, grabbing a fidget spinner or taking a quick walk. We incorporated brain breaks throughout the day, allowing kids to sing songs, do yoga poses and participate in structured physical activities. And for those kids that struggle with sitting for long periods of time, we invested in flexible seating, such as rocking chairs and exercise bikes, and even floor elliptical machines, allowing kids to pedal underneath their desks. These changes encouraged kids to stay in the classroom, helping them to focus and learn. And when less kids are disrupting, all kids do better. And here's the magical thing: it didn't cost us a whole lot of extra money. We simply thought differently about what we had. For example, every public school has an instructional supply line. An instructional supply could be a book, it could be a whiteboard, it could be flexible seating, it could be a fidget spinner, it could even be painting the walls of a school a more calming color, allowing students to thrive. It's not that we didn't invest in the academic tools — obviously — but we took the social tools seriously, too. And the results speak for themselves. By taking the emotional development of our kids seriously and helping them manage their emotions, we saw huge growth in our reading and math scores, far exceeding the one year of expected growth and outscoring many schools with our same demographic. The second thing we did to help our kids manage their emotions was we used leverage. As a not-so-funded public school, we didn't have the support staff to address the chaos that our kids might be facing at home, and we certainly weren't trained or funded to address it directly. So we started to reach out to local groups, community agencies, and even the Ohio State University. Our partnership with the Ohio State University afforded us college students not only studying education but also school psychology and school social work. These students were paired with our teachers to help our most struggling students. And everyone benefitted because our teachers got access to the latest college-level thinking, and those college students got real-world, life experiences in the classroom. Our partnership with our local Nationwide Children's Hospital afforded us — they're building us a health clinic within our school, providing health and mental health resources for our students. And our kids benefitted from this, too. Our absences continued to go down, and our kids had access to counseling that they could access during the school day. And perhaps the biggest change was not in D or in the kids at all. It was in the adults in the room. Teachers are typically good at planning for and delivering academic instruction, but when you throw in disruptive behavior, it can feel completely outside the scope of the job. But by us taking the emotional development of our kids seriously, we moved from a philosophy of exclusion — you disrupt, get out — to one of trust and respect. It wasn't easy, but we felt at heart, it was a positive way to make change, and I'm in awe at the teachers that took that leap with me. As part of our personal professional development plan, we studied the research of Dr. Bruce Perry and his research on the effects of different childhood experiences on the developing child's brain. And what we learned was that some of our students' experiences, such as an absent parent, chaotic home life, poverty and illness, create real trauma on developing brains. Yes, trauma. I know it's a very strong word, but it helped us to reframe and understand the behaviors that we were seeing. And those difficult home experiences created real barbed-wire barriers to learning, and we had to figure out a way over it. So our teachers continued to practice with lesson plans, doing shorter lesson plans with a single focus, allowing kids to engage, and continued to incorporate these movement breaks, allowing kids to jump up and down in class and dance for two minutes straight, because we learned that taking breaks helps the learner retain new information. And might I add that the "Cha-Cha Slide" provides a perfect short dance party. (Laughter) I saw teachers say, "What happened to you?" instead of "What's wrong with you?" or "How can I help you?" instead of "Get out." And this investment in our kids made huge differences, and we continue to see rises in our academic scores. I'm happy to say that when D got to fourth grade, he rarely got into trouble. He became a leader in the school, and this behavior became contagious with other students. We saw and felt our school climate continue to improve, making it a happy and safe place not only for children but for adults, despite any outside influence. Fast-forward to today, I now work with an alternative education program with high school students who struggle to function in traditional high school setting. I recently reviewed some of their histories. Many of them are 17 to 18 years old, experimenting with drugs, in and out of the juvenile detention system and expelled from school. And what I discovered was that many of them exhibit the same behaviors that I saw in six-year-old D. So I can't help but wonder: if these kids would've learned healthy coping strategies early on when times get tough, would they now be able to survive in a regular high school? I can't say for sure, but I have to tell you I believe that it would've helped. And it's time for all of us to take the social and emotional development of our kids seriously. The time is now for us to step up and say what we need to do for our kids. If we teach kids how to read and write, and they graduate but yet they don't know how to manage emotions, what will our communities look like? I tell people: you can invest now or you will pay later. The time is now for us to invest in our kids. They're our future citizens, not just numbers that can or cannot pass a test. Thank you. (Applause and cheers) |
The surprising reason you feel awful when you're sick | null | TED-Ed | It starts with a tickle in your throat that becomes a cough. Your muscles begin to ache, you grow irritable, and you lose your appetite. It's official: you've got the flu. It's logical to assume that this miserable medley of symptoms is the result of the infection coursing through your body, but is that really the case? What's actually making you feel sick? What if your body itself was driving this vicious onslaught? You first get ill when a pathogen like the flu virus gets into your system, infecting and killing your cells. But this unwelcome intrusion has another effect: it alerts your body's immune system to your plight. As soon as it becomes aware of infection, your body leaps to your defense. Cells called macrophages charge in as the first line of attack, searching for and destroying the viruses and infected cells. Afterwards, the macrophages release protein molecules called cytokines whose job is to recruit and organize more virus-busting cells from your immune system. If this coordinated effort is strong enough, it'll wipe out the infection before you even notice it. But that's just your body setting the scene for some real action. In some cases, viruses spread further, even into the blood and vital organs. To avoid this sometimes dangerous fate, your immune system must launch a stronger attack, coordinating its activity with the brain. That's where those unpleasant symptoms come in, starting with the surging temperature, aches and pains, and sleepiness. So why do we experience this? When the immune system is under serious attack, it secretes more cytokines, which trigger two responses. First, the vagus nerve, which runs through the body into the brain, quickly transmits the information to the brain stem, passing near an important area of pain processing. Second, cytokines travel through the body to the hypothalamus, the part of the brain responsible for controlling temperature, thirst, hunger, and sleep, among other things. When it receives this message, the hypothalamus produces another molecule called prostaglandin E2, which gears it up for war. The hypothalamus sends signals that instruct your muscles to contract and causes a rise in body temperature. It also makes you sleepy, and you lose your appetite and thirst. But what's the point of all of these unpleasant symptoms? Well, we're not yet sure, but some theorize that they aid in recovery. The rise in temperature can slow bacteria and help your immune system destroy pathogens. Sleep lets your body channel more energy towards fighting infection. When you stop eating, your liver can take up much of the iron in your blood, and since iron is essential for bacterial survival, that effectively starves them. Your reduced thirst makes you mildly dehydrated, diminishing transmission through sneezes, coughs, vomit, or diarrhea. Though it's worth noting that if you don't drink enough water, that dehydration can become dangerous. Even the body's aches make you more sensitive, drawing attention to infected cuts that might be worsening, or even causing your condition. In addition to physical symptoms, sickness can also make you irritable, sad, and confused. That's because cytokines and prostaglandin can reach even higher structures in your brain, disrupting the activity of neurotransmitters, like glutamate, endorphins, serotonin, and dopamine. This affects areas like the limbic system, which oversees emotions, and your cerebral cortex, which is involved in reasoning. So it's actually the body's own immune response that causes much of the discomfort you feel every time you get ill. Unfortunately, it doesn't always work perfectly. Most notably, millions of people worldwide suffer from autoimmune diseases, in which the immune system treats normal bodily cues as threats, so the body attacks itself. But for the majority of the human race, millions of years of evolution have fine-tuned the immune system so that it works for, rather than against us. The symptoms of our illnesses are annoying, but collectively, they signify an ancient process that will continue barricading our bodies against the outside world for centuries to come. |
The history of Tea | null | TED-Ed | During a long day spent roaming the forest in search of edible grains and herbs, the weary divine farmer Shennong accidentally poisoned himself 72 times. But before the poisons could end his life, a leaf drifted into his mouth. He chewed on it and it revived him, and that is how we discovered tea. Or so an ancient legend goes at least. Tea doesn't actually cure poisonings, but the story of Shennong, the mythical Chinese inventor of agriculture, highlights tea's importance to ancient China. Archaeological evidence suggests tea was first cultivated there as early as 6,000 years ago, or 1,500 years before the pharaohs built the Great Pyramids of Giza. That original Chinese tea plant is the same type that's grown around the world today, yet it was originally consumed very differently. It was eaten as a vegetable or cooked with grain porridge. Tea only shifted from food to drink 1,500 years ago when people realized that a combination of heat and moisture could create a complex and varied taste out of the leafy green. After hundreds of years of variations to the preparation method, the standard became to heat tea, pack it into portable cakes, grind it into powder, mix with hot water, and create a beverage called muo cha, or matcha. Matcha became so popular that a distinct Chinese tea culture emerged. Tea was the subject of books and poetry, the favorite drink of emperors, and a medium for artists. They would draw extravagant pictures in the foam of the tea, very much like the espresso art you might see in coffee shops today. In the 9th century during the Tang Dynasty, a Japanese monk brought the first tea plant to Japan. The Japanese eventually developed their own unique rituals around tea, leading to the creation of the Japanese tea ceremony. And in the 14th century during the Ming Dynasty, the Chinese emperor shifted the standard from tea pressed into cakes to loose leaf tea. At that point, China still held a virtual monopoly on the world's tea trees, making tea one of three essential Chinese export goods, along with porcelain and silk. This gave China a great deal of power and economic influence as tea drinking spread around the world. That spread began in earnest around the early 1600s when Dutch traders brought tea to Europe in large quantities. Many credit Queen Catherine of Braganza, a Portuguese noble woman, for making tea popular with the English aristocracy when she married King Charles II in 1661. At the time, Great Britain was in the midst of expanding its colonial influence and becoming the new dominant world power. And as Great Britain grew, interest in tea spread around the world. By 1700, tea in Europe sold for ten times the price of coffee and the plant was still only grown in China. The tea trade was so lucrative that the world's fastest sailboat, the clipper ship, was born out of intense competition between Western trading companies. All were racing to bring their tea back to Europe first to maximize their profits. At first, Britain paid for all this Chinese tea with silver. When that proved too expensive, they suggested trading tea for another substance, opium. This triggered a public health problem within China as people became addicted to the drug. Then in 1839, a Chinese official ordered his men to destroy massive British shipments of opium as a statement against Britain's influence over China. This act triggered the First Opium War between the two nations. Fighting raged up and down the Chinese coast until 1842 when the defeated Qing Dynasty ceded the port of Hong Kong to the British and resumed trading on unfavorable terms. The war weakened China's global standing for over a century. The British East India company also wanted to be able to grow tea themselves and further control the market. So they commissioned botanist Robert Fortune to steal tea from China in a covert operation. He disguised himself and took a perilous journey through China's mountainous tea regions, eventually smuggling tea trees and experienced tea workers into Darjeeling, India. From there, the plant spread further still, helping drive tea's rapid growth as an everyday commodity. Today, tea is the second most consumed beverage in the world after water, and from sugary Turkish Rize tea, to salty Tibetan butter tea, there are almost as many ways of preparing the beverage as there are cultures on the globe. |
What causes cavities? | null | TED-Ed | When a team of archaeologists recently came across some 15,000 year-old human remains, they made an interesting discovery. The teeth of those ancient humans were riddled with holes. Their cavities were caused by the same thing that still plagues us today, specific tiny microbes that live in our mouths. These microbes are with us soon after birth. We typically pick them up as babies from our mothers' mouths. And as our teeth erupt, they naturally begin to accumulate communities of bacteria. Depending on what we eat, and specifically how much sugar we consume, certain microbes can overpopulate and cause cavities. Diets high in sugary foods cause an explosion of bacteria called mutans streptococci in our mouths. Like humans, these microorganisms love sugar, using it as a molecular building block and energy source. As they consume it, the bacteria generate byproducts in the form of acids, such as lactic acid. Mutans streptococci are resistant to this acid, but unfortunately, our teeth aren't. While each human tooth is coated in a hardy, protective layer of enamel, it's no match for acid. That degrades the armor over time, leaching away its calcium minerals. Gradually, acid wears down a pathway for bacteria into the tooth's secondary layer called the dentin. Since blood vessels and nerves in our teeth are enclosed deep within, at this stage, the expanding cavity doesn't hurt. But if the damage extends beyond the dentin, the bacterial invasion progresses causing excruciating pain as the nerves become exposed. Without treatment, the whole tooth may become infected and require removal all due to those sugar-loving bacteria. The more sugar our food contains, the more our teeth are put at risk. Those cavemen would hardly have indulged in sugary treats, however, so what caused their cavities? In meat-heavy diets, there would have been a low-risk of cavities developing because lean meat contains very little sugar, but that's not all our early human ancestors ate. Cavemen would also have consumed root vegetables, nuts, and grains, all of which contain carbohydrates. When exposed to enzymes in the saliva, carbohydrates get broken down into simpler sugars, which can become the fodder for those ravenous mouth bacteria. So while ancient humans did eat less sugar compared to us, their teeth were still exposed to sugars. That doesn't mean they were unable to treat their cavities, though. Archaeological remains show that about 14,000 years ago, humans were already using sharpened flint to remove bits of rotten teeth. Ancient humans even made rudimentary drills to smooth out the rough holes left behind and beeswax to plug cavities, like modern-day fillings. Today, we have much more sophisticated techniques and tools, which is fortunate because we also need to contend with our more damaging, sugar-guzzling ways. After the Industrial Revolution, the human incidence of cavities surged because suddenly we had technological advances that made refined sugar cheaper and accessible. Today, an incredible 92% of American adults have had cavities in their teeth. Some people are more susceptible to cavities due to genes that may cause certain weaknesses, like softer enamel, but for most, high sugar consumption is to blame. However, we have developed other ways of minimizing cavities besides reducing our intake of sugar and starch. In most toothpastes and many water supplies, we use tiny amounts of fluoride. That strengthens teeth and encourages the growth of enamel crystals that build up a tooth's defenses against acid. When cavities do develop, we use tooth fillings to fill and close off the infected area, preventing them from getting worse. The best way to avoid a cavity is still cutting down on sugar intake and practicing good oral hygiene to get rid of the bacteria and their food sources. That includes regular tooth brushing, flossing, and avoiding sugary, starchy, and sticky foods that cling to your teeth between meals. Gradually, the population of sugar-loving microbes in your mouth will decline. Unlike the cavemen of yesteryear, today we have the knowledge required to avert a cavity calamity. We just need to use it. |
A brief history of plural word...s | {0: 'Linguist John McWhorter thinks about language in relation to race, politics and our shared cultural history.'} | TED-Ed | There are a lot of ways this marvelous language of ours, English, doesn't make sense. For example, most of the time when we talk about more than one of something, we put an S on the end. One cat, two cats. But then, there's that handful of words where things work differently. Alone you have a man; if he has company, then you've got men, or probably better for him, women too. Although if there were only one of them, it would be a woman. Or if there's more than one goose, they're geese, but why not lots of mooses, meese? Or if you have two feet, then why don't you read two beek instead of books. The fact is that if you were speaking English before about a thousand years ago, beek is exactly what you would have said for more than one book. If Modern English is strange, Old English needed therapy. Believe it or not, English used to be an even harder language to learn than it is today. Twenty-five hundred years ago, English and German were the same language. They drifted apart slowly, little by little becoming more and more different. That meant that in early English, just like in German, inanimate objects had gender. A fork, gafol, was a woman; a spoon, laefel, was a man; and the table they were on, bord, was neither, also called neuter. Go figure! Being able to use words meant not just knowing their meaning but what gender they were, too. And while today there are only about a dozen plurals that don't make sense, like men and geese, in Old English, it was perfectly normal for countless plurals to be like that. You think it's odd that more than one goose is geese? Well, imagine if more than one goat was a bunch of gat, or if more than one oak tree was a field of ack. To be able to talk about any of these, you just had to know the exact word for their plural rather than just adding the handy S on the end. And it wasn't always an S at the end either. In merry Old English, they could add other sounds to the end. Just like more than one child is children, more than one lamb was lambru, you fried up your eggru, and people talked not about breads, but breadru. Sometimes it was like sheep is today - where, to make a plural, you don't do anything. One sheep, two sheep. In Old English, one house, two house. And just like today, we have oxen instead of oxes. Old English people had toungen instead of tongues, namen instead of names, and if things stayed the way they were, today we would have eyen instead of eyes. So, why didn't things stay the way they were? In a word, Vikings. In the 8th century, Scandinavian marauders started taking over much of England. They didn't speak English, they spoke Norse. Plus, they were grown-ups, and grown-ups aren't as good at learning languages as children. After the age of roughly 15, it's almost impossible to learn a new language without an accent and without slipping up here and there as we all know from what language classes are like. The Vikings were no different, so they had a way of smoothing away the harder parts of how English worked. Part of that was those crazy plurals. Imagine running up against a language with eggru and gat on the one hand, and then with other words, all you have to do is add 's' and get days and stones. Wouldn't it make things easier to just use the 's' for everything? That's how the Vikings felt too. And there were so many of them, and they married so many of the English women, that pretty soon, if you grew up in England, you heard streamlined English as much as the real kind. After a while nobody remembered the real kind any more. Nobody remembered that once you said doora instead of doors and handa instead of hands. Plurals made a lot more sense now, except for a few hold-outs like children and teeth that get used so much that it was hard to break the habit. The lesson is that English makes a lot more sense than you think. Thank the ancestors of people in Copenhagen and Oslo for the fact that today we don't ask for a handful of pea-night instead of peanuts. Although, wouldn't it be fun, if for just a week or two, we could? |
The beautiful future of solar power | {0: 'Marjan van Aubel promotes extreme energy efficiency through intelligent design.'} | TEDxAmsterdamWomen | Last summer, I was hiking through the Austrian mountains. And there, on top, I saw this beautiful, stone, remote hut, and it had solar panels on it. And every time I see solar panels, I get very enthusiastic. It's this technology that takes sunlight, which is free and available, and turns that into electricity. So this hut, in the middle of nowhere, on a beautiful location, was self-sufficient. But why do solar panels always have to be so ugly? (Laughter) My name is Marjan Van Aubel and I'm a solar designer. I work in the triangle of design, sustainability and technology. I strive for extreme efficiency, meaning that I develop materials that expand in size or work with solar cells that use the properties of colors to generate electricity. My work is in museums all over the world, such as MoMA. And, I mean, it all went quite well, but it always felt that something was missing. And it was, until I read the book called the "Solar Revolution," where it says that within one hour we receive enough sunlight to provide the world with enough electricity for an entire year. One hour. And since then, I realized I just want to focus on solar. Scientists all over the world have been focusing on making solar panels more efficient and cheaper. So the price of solar has dropped enormously. And this is because China started producing them on a large scale. And also their efficiency has increased a lot. They now even have an efficiency of 44.5 percent. But if you think about the image of solar cells, it's kind of stayed the same for the last 60 years. It's still this technology just stacked onto something. And solar cells need to be much better integrated into our environment. Climate change is the biggest problem of our time. And we can't rely on the others — the government, the engineers — to make positive changes. We all can contribute towards change. Like I said, I'm a designer and I would like to change things through design. Let me give you some examples of my work. I'm collaborating with Swarovski, the crystal company. And if you cut crystals in a certain way, you are able to bend and direct the light onto a certain place. So I use these crystals to focus the light onto a solar panel, making them more efficient, but using aesthetics. So you take the solar crystal with you in the light, there's a battery in the solar cell, you put it in a docking station and you are able to power these chandeliers. So you're literally bringing the light indoors. I got completely hooked on solar when I came across this technology called dye-sensitized solar cells, colored solar cells, and they are based on photosynthesis in plants. Where the green chlorophyl converts light into sugar for plants, these cells convert light into electricity. The best thing is, they even work indoors. So different colors have different efficiency, depending on their place on the color spectrum. So, for example, red is more efficient than blue. So if I hear this as a designer: a colored surface, a glass colored surface, color that's mostly just used for esthetics, now gets an extra function and is able to harvest electricity, I think, where can we apply this, then? This is Current Table, where the whole tabletop consists of these colored solar cells. There are batteries in the legs where you can charge your phone through USB ports. And in my work, it's always very important, the balance between efficiency and aesthetics. So that's why the table is orange, because it is a very stable color for indoors. And this is always the most asked question I get: "OK, great, but how many phones can I charge from this, then?" And before I go to this complicated answer of like, "Well, where is the table, does it have enough light, is it next to a window?" The table now has sensors that read the light intensity of the room. So through an app we developed you can literally follow how much light it's getting, and how full the battery is. I'm actually proud, because yesterday we installed a table at Stichting Doen's offices in Amsterdam and, right at this moment, our Queen Maxima is charging a phone from this table. It's cool. (Applause) So the more surface you have, the more energy you can harvest. These are Current Windows, where we replaced all windows in a gallery in London, in Soho, with this modern version of stained glass. So people from the street could come and charge their phones through the window ledges. So I'm giving extra functions to objects. A window doesn't have to be just a window anymore. It can also function as a little power station. So, here I am, talking about how much I love solar, but I don't have solar panels on my roof. I live in the center of Amsterdam, I don't own the house and it's a monument, so it's not possible and not allowed. So how can you make solar cells more accessible and for everyone, and not only for the people that can afford a sustainable lifestyle? We now have the opportunity to integrate solar on the place where we directly need it. And there are so many amazing technologies out there. If I look around now, I see every surface as an opportunity. For example, I was driving in the train through the Westland, the area in the Netherlands with all the greenhouses. There I saw all this glass and thought, what if we integrate those with transparent solar glass? What if we integrate traditional farming that requires a lot of energy together with high-tech and combine those? With this idea in mind, I created Power Plant. I had a team of architects and engineers, but let me first explain how it works. We use transparent solar glass to power its indoor climate. We use hydroponics that pumps around nutrified water, saving 90 percent of water usage. By stacking up in layers, you are able to grow more yield per square meter. Extra light, besides sunlight, coming from these colored LED lights also enhances plant growth. As more and more people will live in big cities, by placing Power Plants on the rooftops you don't have to fly it in from the other side of the world, you are able to grow it on the location itself. Well, the big dream is to build these in off-grid places — where there's no access to water, electricity — as an independent ecosystem. For this year's Design Biennial, I created the first four-meter high model of the power plant, so you could come in and experience how plants grow. So it's a double harvest of sunlight, so both for the solar cells and for the plants. It's like a future botanical garden, where we celebrate all these modern technologies. And the biggest compliment I got was, "But where are the solar panels?" And that's when I think design really works, when it becomes invisible and you don't notice it. I believe in solar democracy: solar energy for everyone, everywhere. My aim is to make all surfaces productive. I want to build houses where all the windows, curtains, walls, even floors are harvesting electricity. Think about this on a big scale: in cities, there are so many surfaces. The sun is still available for everyone. And by integrating solar on the place where we need it, we now have the opportunity to make solar cells accessible for everyone. I want to bring solar close to the people with you, but beautiful and well designed. Thank you. |
A brief history of goths | null | TED-Ed | What do fans of atmospheric post-punk music have in common with ancient barbarians? Not much. So why are both known as goths? Is it a weird coincidence or a deeper connection stretching across the centuries? The story begins in Ancient Rome. As the Roman Empire expanded, it faced raids and invasions from the semi-nomadic populations along its borders. Among the most powerful were a Germanic people known as Goths who were composed of two tribal groups, the Visigoths and Ostrogoths. While some of the Germanic tribes remained Rome's enemies, the Empire incorporated others into the imperial army. As the Roman Empire split in two, these tribal armies played larger roles in its defense and internal power struggles. In the 5th century, a mercenary revolt lead by a soldier named Odoacer captured Rome and deposed the Western Emperor. Odoacer and his Ostrogoth successor Theoderic technically remained under the Eastern Emperor's authority and maintained Roman traditions. But the Western Empire would never be united again. Its dominions fragmented into kingdoms ruled by Goths and other Germanic tribes who assimilated into local cultures, though many of their names still mark the map. This was the end of the Classical Period and the beginning of what many call the Dark Ages. Although Roman culture was never fully lost, its influence declined and new art styles arose focused on religious symbolism and allegory rather than proportion and realism. This shift extended to architecture with the construction of the Abbey of Saint Denis in France in 1137. Pointed arches, flying buttresses, and large windows made the structure more skeletal and ornate. That emphasized its open, luminous interior rather than the sturdy walls and columns of Classical buildings. Over the next few centuries, this became a model for Cathedrals throughout Europe. But fashions change. With the Italian Renaissance's renewed admiration for Ancient Greece and Rome, the more recent style began to seem crude and inferior in comparison. Writing in his 1550 book, "Lives of the Artists," Giorgio Vasari was the first to describe it as Gothic, a derogatory reference to the Barbarians thought to have destroyed Classical civilization. The name stuck, and soon came to describe the Medieval period overall, with its associations of darkness, superstition, and simplicity. But time marched on, as did what was considered fashionable. In the 1700s, a period called the Enlightenment came about, which valued scientific reason above all else. Reacting against that, Romantic authors like Goethe and Byron sought idealized visions of a past of natural landscapes and mysterious spiritual forces. Here, the word Gothic was repurposed again to describe a literary genre that emerged as a darker strain of Romanticism. The term was first applied by Horace Walpole to his own 1764 novel, "The Castle of Otranto" as a reference to the plot and general atmosphere. Many of the novel's elements became genre staples inspiring classics and the countless movies they spawned. The gothic label belonged to literature and film until the 1970s when a new musical scene emerged. Taking cues from artists like The Doors and The Velvet Underground, British post-punk groups, like Joy Division, Bauhaus, and The Cure, combined gloomy lyrics and punk dissonance with imagery inspired by the Victorian era, classic horror, and androgynous glam fashion. By the early 1980s, similar bands were consistently described as Gothic rock by the music press, and the stye's popularity brought it out of dimly lit clubs to major labels and MTV. And today, despite occasional negative media attention and stereotypes, Gothic music and fashion continue as a strong underground phenomenon. They've also branched into sub-genres, such as cybergoth, gothabilly, gothic metal, and even steampunk. The history of the word gothic is embedded in thousands of years worth of countercultural movements, from invading outsiders becoming kings to towering spires replacing solid columns to artists finding beauty in darkness. Each step has seen a revolution of sorts and a tendency for civilization to reach into its past to reshape its present. |
How fast are you moving right now? | null | TED-Ed | How fast are you moving right now? That seems like an easy question. The first tempting answer is, "I'm not moving." Upon further reflection, you realize that maybe the Earth's motion counts. So, a second tempting answer is, "19 miles/second around the Sun." But then you recall learning that the Sun moves around the center of the Milky Way galaxy, and the Milky Way moves within the Local Group of galaxies, and the Local Group moves within the Virgo Cluster, and the Virgo Cluster moves within... "How fast are you moving?" is not an easy question. When Mission Control tells astronauts how fast they're going, there's always an assumed standard of rest. At the start of the voyage, speeds are given relative to the launchpad. But later, when the launchpad is just one more arbritrary place down there on Earth's spinning surface, speeds are given relative to the idealized, non-spinning pinpoint center of Earth. On their way to the Moon, Apollo astronauts had a hard time answering the question, "How fast are you moving?" Speed away from Earth was one thing, and speed toward the Moon was quite another. That's because the Earth and the Moon move relative to one another. Ah, of course! Speed is a relative quantity. When Captain Kirk ask Lieutenant Sulu if the Starship Enterprise has reached a speed of warp 7, Sulu should reply, "Relative to what, Captain?" Such a sassy reply may get subordinate Starfleet officers in trouble, but it is the only good answer to the question, "How fast are you moving?" This is basic relatively talking. Not fancy Einsteinian relativity, but good old fashioned (and still correct) Galilean relativity. Galileo seems to have been the first person to realize that there is no such thing as an absolute speed. Speeds are relative. This means that speeds only have meaning when they are referred to a reference frame. Presumably that reference frame is itself at rest. But then we have to ask again, "At rest relative to what?" Because even the concept of rest has lost any hint of absolute meaning. Speed is relative, and rest is relative. Earth's speed is 19 miles/second relative to the Sun. The Enterprise's speed is warp 7 relative to the center of the Milky Way galaxy. Your speed is zero relative to your easy chair. But depending on where you sit, it is hundreds of miles/hour relative to Earth's center. When we furrow a brow and ask, "But how fast is Earth really moving?" we imagine Spaceship Earth plowing through the ocean of space as it orbits the Sun. But space is not an ocean. It has no substance as water does. Space is not a thing; space is nothing. Space is no thing. You can move between two points in space, say between Earth and Mars, but you can't move through space. There's nothing to move through. It's like trying to say how much a hole weighs. A hole weighs exactly nothing because a hole is nothing. It's a void, and so is space. To move relative to nothing is meaningless. The concepts of speed and of rest have only relative meaning. They are absolutely meaningless. They mean something only with respect to arbitrarily chosen, artificial frames of reference. If, someday, you are buckled into your spaceship, and you see from the side window, say, a space station whizz by at constant speed, there is no way to know which of you is really moving. Neither of you is really moving because there is no deep reality about constant speed. Constant speed in a straight line has only relative meaning, a kind of relative reality. Does this mean that all motion is relative? No! Some motions have only relative meaning, but some motions have absolute meaning, are absolutely real. For example, constant speed is relative, but change in speed is absolute. Calling something absolute in science means that arbitrary standards are not used in its measurement. It is unambiguously measurable. When your spaceship fires its engines, your change in speed is beyond doubt. You feel it in your stomach, and your ship's sensors can measure it. Outside your window, the passing space station may seem to be changing speed, but the beings inside the station will not feel it. And no sensors can measure it. You are really changing speed, and they are really are not. There's something absolutely real about changes in speed. The same goes for rotation. If your spaceship is spinning, you can feel it, and your ship's sensors can measure it. The space station outside may seem to be going around you, but it is you who feels queasy, not the folks in the space station. You are really spinning, and they really are not. There's something absolutely real about rotation. So, some motions are relative, and some are not. There is no deep reality about constant speed, but changes in speed are deeply real, and so are rotations. We have to be thoughtful in our analysis of everyday experience in order to identify what is deeply real. Since we can be fooled by perceptions as basic as speed, maybe every perception deserves careful scrutiny. This is what inspired Einstein to his incredible insights about the speed of light and forward time travel. Knowing how to identify what is deeply real is tough and important work. If a police officer ever pulls you over for speeding and asks, "Do you know how fast you were going?" an insightful, though perhaps unwise, reply would be, "Relative to what?" And then, as you sit in the backseat of the police car and feel it accelerate toward jail, you can add, "But some things are absolute!" |
What is a calorie? | null | TED-Ed | We hear about calories all the time. How many calories are in this cookie? How many are burned by 100 jumping jacks, or long distance running, or fidgeting? But what is a calorie, really, and how many of them do we actually need? Calories are a way of keeping track of the body's energy budget. A healthy balance occurs when we put in about as much energy as we lose. If we consistently put more energy into our bodies than we burn, the excess will gradually be stored as fat in our cells, and we'll gain weight. If we burn off more energy than we replenish, we'll lose weight. So we have to be able to measure the energy we consume and use, and we do so with a unit called the calorie. One calorie, the kind we measure in food, also called a large calorie, is defined as the amount of energy it would take to raise the temperature of one kilogram of water by one degree Celsius. Everything we consume has a calorie count, a measure of how much energy the item stores in its chemical bonds. The average pizza slice has 272 calories, there are about 78 in a piece of bread, and an apple has about 52. That energy is released during digestion, and stored in other molecules that can be broken down to provide energy when the body needs it. It's used in three ways: about 10% enables digestion, about 20% fuels physical activity, and the biggest chunk, around 70%, supports the basic functions of our organs and tissues. That third usage corresponds to your basal metabolic rate, a number of calories you would need to survive if you weren't eating or moving around. Add in some physical activity and digestion, and you arrive at the official guidelines for how many calories the average person requires each day: 2000 for women and 2500 for men. Those estimates are based on factors like average weight, physical activity and muscle mass. So does that mean everyone should shoot for around 2000 calories? Not necessarily. If you're doing an energy guzzling activity, like cycling the Tour de France, your body could use up to 9000 calories per day. Pregnancy requires slightly more calories than usual, and elderly people typically have a slower metabolic rate, energy is burned more gradually, so less is needed. Here's something else you should know before you start counting calories. The calorie counts on nutrition labels measure how much energy the food contains, not how much energy you can actually get out of it. Fibrous foods like celery and whole wheat take more energy to digest, so you'd actually wind up with less energy from a 100 calorie serving of celery than a 100 calorie serving of potato chips. Not to mention the fact that some foods offer nutrients like protein and vitamins, while others provide far less nutritional value. Eating too many of those foods could leave you overweight and malnourished. And even with the exact same food, different people might not get the same number of calories. Variations in things like enzyme levels, gut bacteria, and even intestine length, means that every individual's ability to extract energy from food is a little different. So a calorie is a useful energy measure, but to work out exactly how many of them each of us requires we need to factor in things like exercise, food type, and our body's ability to process energy. Good luck finding all of that on a nutrition label. |
The psychology behind irrational decisions | null | TED-Ed | Let's say you're on a game show. You've already earned $1000 in the first round when you land on the bonus space. Now, you have a choice. You can either take a $500 bonus guaranteed or you can flip a coin. If it's heads, you win $1000 bonus. If it's tails, you get no bonus at all. In the second round, you've earned $2000 when you land on the penalty space. Now you have another choice. You can either take a $500 loss, or try your luck at the coin flip. If it's heads, you lose nothing, but if it's tails, you lose $1000 instead. If you're like most people, you probably chose to take the guaranteed bonus in the first round and flip the coin in the second round. But if you think about it, this makes no sense. The odds and outcomes in both rounds are exactly the same. So why does the second round seem much scarier? The answer lies in a phenomenon known as loss aversion. Under rational economic theory, our decisions should follow a simple mathematical equation that weighs the level of risk against the amount at stake. But studies have found that for many people, the negative psychological impact we feel from losing something is about twice as strong as the positive impact of gaining the same thing. Loss aversion is one cognitive bias that arises from heuristics, problem-solving approaches based on previous experience and intuition rather than careful analysis. And these mental shortcuts can lead to irrational decisions, not like falling in love or bungee jumping off a cliff, but logical fallacies that can easily be proven wrong. Situations involving probability are notoriously bad for applying heuristics. For instance, say you were to roll a die with four green faces and two red faces twenty times. You can choose one of the following sequences of rolls, and if it shows up, you'll win $25. Which would you pick? In one study, 65% of the participants who were all college students chose sequence B even though A is shorter and contained within B, in other words, more likely. This is what's called a conjunction fallacy. Here, we expect to see more green rolls, so our brains can trick us into picking the less likely option. Heuristics are also terrible at dealing with numbers in general. In one example, students were split into two groups. The first group was asked whether Mahatma Gandhi died before or after age 9, while the second was asked whether he died before or after age 140. Both numbers were obviously way off, but when the students were then asked to guess the actual age at which he died, the first group's answers averaged to 50 while the second group's averaged to 67. Even though the clearly wrong information in the initial questions should have been irrelevant, it still affected the students' estimates. This is an example of the anchoring effect, and it's often used in marketing and negotiations to raise the prices that people are willing to pay. So, if heuristics lead to all these wrong decisions, why do we even have them? Well, because they can be quite effective. For most of human history, survival depended on making quick decisions with limited information. When there's no time to logically analyze all the possibilities, heuristics can sometimes save our lives. But today's environment requires far more complex decision-making, and these decisions are more biased by unconscious factors than we think, affecting everything from health and education to finance and criminal justice. We can't just shut off our brain's heuristics, but we can learn to be aware of them. When you come to a situation involving numbers, probability, or multiple details, pause for a second and consider that the intuitive answer might not be the right one after all. |
How the food you eat affects your brain | null | TED-Ed | Your Brain on Food If you sucked all of the moisture out of your brain and broke it down to its constituent nutritional content, what would it look like? Most of the weight of your dehydrated brain would come from fats, also known as lipids. In the remaining brain matter, you would find proteins and amino acids, traces of micronutrients, and glucose. The brain is, of course, more than just the sum of its nutritional parts, but each component does have a distinct impact on functioning, development, mood, and energy. So that post-lunch apathy, or late-night alertness you might be feeling, well, that could simply be the effects of food on your brain. Of the fats in your brain, the superstars are omegas 3 and 6. These essential fatty acids, which have been linked to preventing degenerative brain conditions, must come from our diets. So eating omega-rich foods, like nuts, seeds, and fatty fish, is crucial to the creation and maintenance of cell membranes. And while omegas are good fats for your brain, long-term consumption of other fats, like trans and saturated fats, may compromise brain health. Meanwhile, proteins and amino acids, the building block nutrients of growth and development, manipulate how we feel and behave. Amino acids contain the precursors to neurotransmitters, the chemical messengers that carry signals between neurons, affecting things like mood, sleep, attentiveness, and weight. They're one of the reasons we might feel calm after eating a large plate of pasta, or more alert after a protein-rich meal. The complex combinations of compounds in food can stimulate brain cells to release mood-altering norepinephrine, dopamine, and serotonin. But getting to your brain cells is tricky, and amino acids have to compete for limited access. A diet with a range of foods helps maintain a balanced combination of brain messengers, and keeps your mood from getting skewed in one direction or the other. Like the other organs in our bodies, our brains also benefit from a steady supply of micronutrients. Antioxidants in fruits and vegetables strengthen the brain to fight off free radicals that destroy brain cells, enabling your brain to work well for a longer period of time. And without powerful micronutrients, like the vitamins B6, B12, and folic acid, our brains would be susceptible to brain disease and mental decline. Trace amounts of the minerals iron, copper, zinc, and sodium are also fundamental to brain health and early cognitive development. In order for the brain to efficiently transform and synthesize these valuable nutrients, it needs fuel, and lots of it. While the human brain only makes up about 2% of our body weight, it uses up to 20% of our energy resources. Most of this energy comes from carbohydrates that our body digests into glucose, or blood sugar. The frontal lobes are so sensitive to drops in glucose, in fact, that a change in mental function is one of the primary signals of nutrient deficiency. Assuming that we are getting glucose regularly, how does the specific type of carbohydrates we eat affect our brains? Carbs come in three forms: starch, sugar, and fiber. While on most nutrition labels, they are all lumped into one total carb count, the ratio of the sugar and fiber subgroups to the whole amount affect how the body and brain respond. A high glycemic food, like white bread, causes a rapid release of glucose into the blood, and then comes the dip. Blood sugar shoots down, and with it, our attention span and mood. On the other hand, oats, grains, and legumes have slower glucose release, enabling a steadier level of attentiveness. For sustained brain power, opting for a varied diet of nutrient-rich foods is critical. When it comes to what you bite, chew, and swallow, your choices have a direct and long-lasting effect on the most powerful organ in your body. |
Is math discovered or invented? | null | TED-Ed | Would mathematics exist if people didn't? Since ancient times, mankind has hotly debated whether mathematics was discovered or invented. Did we create mathematical concepts to help us understand the universe around us, or is math the native language of the universe itself, existing whether we find its truths or not? Are numbers, polygons and equations truly real, or merely ethereal representations of some theoretical ideal? The independent reality of math has some ancient advocates. The Pythagoreans of 5th Century Greece believed numbers were both living entities and universal principles. They called the number one, "the monad," the generator of all other numbers and source of all creation. Numbers were active agents in nature. Plato argued mathematical concepts were concrete and as real as the universe itself, regardless of our knowledge of them. Euclid, the father of geometry, believed nature itself was the physical manifestation of mathematical laws. Others argue that while numbers may or may not exist physically, mathematical statements definitely don't. Their truth values are based on rules that humans created. Mathematics is thus an invented logic exercise, with no existence outside mankind's conscious thought, a language of abstract relationships based on patterns discerned by brains, built to use those patterns to invent useful but artificial order from chaos. One proponent of this sort of idea was Leopold Kronecker, a professor of mathematics in 19th century Germany. His belief is summed up in his famous statement: "God created the natural numbers, all else is the work of man." During mathematician David Hilbert's lifetime, there was a push to establish mathematics as a logical construct. Hilbert attempted to axiomatize all of mathematics, as Euclid had done with geometry. He and others who attempted this saw mathematics as a deeply philosophical game but a game nonetheless. Henri Poincaré, one of the father's of non-Euclidean geometry, believed that the existence of non-Euclidean geometry, dealing with the non-flat surfaces of hyperbolic and elliptical curvatures, proved that Euclidean geometry, the long standing geometry of flat surfaces, was not a universal truth, but rather one outcome of using one particular set of game rules. But in 1960, Nobel Physics laureate Eugene Wigner coined the phrase, "the unreasonable effectiveness of mathematics," pushing strongly for the idea that mathematics is real and discovered by people. Wigner pointed out that many purely mathematical theories developed in a vacuum, often with no view towards describing any physical phenomena, have proven decades or even centuries later, to be the framework necessary to explain how the universe has been working all along. For instance, the number theory of British mathematician Gottfried Hardy, who had boasted that none of his work would ever be found useful in describing any phenomena in the real world, helped establish cryptography. Another piece of his purely theoretical work became known as the Hardy-Weinberg law in genetics, and won a Nobel prize. And Fibonacci stumbled upon his famous sequence while looking at the growth of an idealized rabbit population. Mankind later found the sequence everywhere in nature, from sunflower seeds and flower petal arrangements, to the structure of a pineapple, even the branching of bronchi in the lungs. Or there's the non-Euclidean work of Bernhard Riemann in the 1850s, which Einstein used in the model for general relativity a century later. Here's an even bigger jump: mathematical knot theory, first developed around 1771 to describe the geometry of position, was used in the late 20th century to explain how DNA unravels itself during the replication process. It may even provide key explanations for string theory. Some of the most influential mathematicians and scientists of all of human history have chimed in on the issue as well, often in surprising ways. So, is mathematics an invention or a discovery? Artificial construct or universal truth? Human product or natural, possibly divine, creation? These questions are so deep the debate often becomes spiritual in nature. The answer might depend on the specific concept being looked at, but it can all feel like a distorted zen koan. If there's a number of trees in a forest, but no one's there to count them, does that number exist? |
How computer memory works | null | TED-Ed | In many ways, our memories make us who we are, helping us remember our past, learn and retain skills, and plan for the future. And for the computers that often act as extensions of ourselves, memory plays much the same role, whether it's a two-hour movie, a two-word text file, or the instructions for opening either, everything in a computer's memory takes the form of basic units called bits, or binary digits. Each of these is stored in a memory cell that can switch between two states for two possible values, 0 and 1. Files and programs consist of millions of these bits, all processed in the central processing unit, or CPU, that acts as the computer's brain. And as the number of bits needing to be processed grows exponentially, computer designers face a constant struggle between size, cost, and speed. Like us, computers have short-term memory for immediate tasks, and long-term memory for more permanent storage. When you run a program, your operating system allocates area within the short-term memory for performing those instructions. For example, when you press a key in a word processor, the CPU will access one of these locations to retrieve bits of data. It could also modify them, or create new ones. The time this takes is known as the memory's latency. And because program instructions must be processed quickly and continuously, all locations within the short-term memory can be accessed in any order, hence the name random access memory. The most common type of RAM is dynamic RAM, or DRAM. There, each memory cell consists of a tiny transistor and a capacitor that store electrical charges, a 0 when there's no charge, or a 1 when charged. Such memory is called dynamic because it only holds charges briefly before they leak away, requiring periodic recharging to retain data. But even its low latency of 100 nanoseconds is too long for modern CPUs, so there's also a small, high-speed internal memory cache made from static RAM. That's usually made up of six interlocked transistors which don't need refreshing. SRAM is the fastest memory in a computer system, but also the most expensive, and takes up three times more space than DRAM. But RAM and cache can only hold data as long as they're powered. For data to remain once the device is turned off, it must be transferred into a long-term storage device, which comes in three major types. In magnetic storage, which is the cheapest, data is stored as a magnetic pattern on a spinning disc coated with magnetic film. But because the disc must rotate to where the data is located in order to be read, the latency for such drives is 100,000 times slower than that of DRAM. On the other hand, optical-based storage like DVD and Blu-ray also uses spinning discs, but with a reflective coating. Bits are encoded as light and dark spots using a dye that can be read by a laser. While optical storage media are cheap and removable, they have even slower latencies than magnetic storage and lower capacity as well. Finally, the newest and fastest types of long-term storage are solid-state drives, like flash sticks. These have no moving parts, instead using floating gate transistors that store bits by trapping or removing electrical charges within their specially designed internal structures. So how reliable are these billions of bits? We tend to think of computer memory as stable and permanent, but it actually degrades fairly quickly. The heat generated from a device and its environment will eventually demagnetize hard drives, degrade the dye in optical media, and cause charge leakage in floating gates. Solid-state drives also have an additional weakness. Repeatedly writing to floating gate transistors corrodes them, eventually rendering them useless. With data on most current storage media having less than a ten-year life expectancy, scientists are working to exploit the physical properties of materials down to the quantum level in the hopes of making memory devices faster, smaller, and more durable. For now, immortality remains out of reach, for humans and computers alike. |
Why do your knuckles pop? | null | TED-Ed | What's that sound? Depending on whom you ask, the crackle of popping joints is either the sound of sweet relief or the noxious tones of a stomach-turning habit. Really, though. What's that sound? I mean, why does bending your joints in a certain way make them pop like that? Scientists have offered several explanations, including rapidly stretching ligaments, and in severe cases, actual bones grinding against each other. But the most common explanation for why your stretched-out joints sound like bubbles popping is that, well, there are bubbles in there. The joints in your fingers are the easiest ones to crack, but many people also crack the joints between vertebrae in their neck and back, and even their hips, wrists, shoulders and so on. All these joints are synovial joints, and they're the most flexible ones in your body. The space between the two bones is filled with a viscous liquid, synovial fluid, which contains long, lubricating molecules, like hyaluronic acid and lubricin. Synovial fluid is more or less the texture of egg yolk and its primary purpose is to cushion the bones and help them glide past each other. It also contains phagocytic cells that help clean up any bone or cartilage debris that ends up in the joint. But the reason it's important for knuckle cracking is that, like other fluids in your body, it contains lots of dissolved gas molecules. Knuckle-crackers know that to get that satisfying pop, you stretch the joint farther than it normally goes by bending your fingers backwards, for example. When you do that, the bones move away from each other. The space between bones gets bigger, but the amount of synovial fluid stays constant. That creates a low-pressure zone that pulls dissolved gases out of the synovial fluid, just like the carbon dioxide that fizzes out of soda when you twist open the cap. Inside the joint, the escaping gases form a bubble with a pop. But the bubble doesn't last long. The surrounding fluid presses on it until it finally collapses. The bubble's gases scatter throughout the synovial cavity and slowly dissolve back into the fluid over the course of about twenty minutes, which is why it can take a while before you can pop the same joint again. Some scientists think there may actually be two pops. One when the bubble forms, and another when it bursts. Popping a joint temporarily enlarges it, which may be why dedicated knuckle-, neck- and back-crackers say the habit makes their joints feel looser and more flexible. But you may have heard from a concerned relative or annoyed officemate that cracking your joints will give you arthritis. A doctor named Donald Unger heard this, too. So, determined to disprove his mother's warnings, he cracked the knuckles of his left hand repeatedly for 50 years, while the right-hand knuckles went unpopped. 36,500 cracks later, both hands were arthritis-free. For this selfless act of devotion to science, Dr. Unger received an Ig Nobel Prize, a parody of the Nobel Prize that recognizes wacky, but weirdly fascinating, scientific accomplishments. Unger wrote that his results should prompt investigation into other parental beliefs, like the importance of eating spinach. The jury's still out on that one. As for knuckle-cracking, one study suggests that all that joint stretching and bubble bursting can cause your hands to swell and weaken your grip. But the biggest proven danger seems to be annoying those around you. |
Sugar: Hiding in plain sight | null | TED-Ed | Sugar is playing hide and seek with you. You'd think it would be pretty easy for you to win, considering all the sugar in sodas, ice cream, candy, and big white bags labeled sugar. People get about half of their added sugars from those drinks and treats, so it might seem like sugar is hiding in plain sight, but like someone in the witness protection program, the other half is hidden in places you'd least suspect. Check the ingredients on ketchup, bologna, spaghetti sauce, soy milk, sports drinks, fish sticks, and peanut butter. You'll find sugar hiding in most of those products. In fact, you'll find added sugars in three-quarters of the more than 600,000 items available in grocery stores. But how is sugar hiding? Can't you just look on food labels? It's not that easy. Just like your friend Robert might go by Bob, Robby, Rob, Bobby, or Roberto, added sugar has a lot of aliases. And by a lot, we don't mean five or six, try fifty-six. There's brown rice syrup, barley malt, demerara, Florida Crystals, muscovado, and, of course, high fructose corn syrup, sometimes called HFCS, or corn sugar. Even sugar's tricky nicknames have nicknames. Grape or apple concentrate has the same effects on your body as its 55 sugary twins. And even though organic evaporated cane juice sounds healthy, when you evaporate it, you get sugar! Chemically speaking, it's all the same. And even trickier, when multiple added types of sugars are used in one type of product, they get buried down in a long list of ingredients, so the sugar content might appear to be okay, but when you add them all together, sugar can be the single biggest ingredient. Currently, the FDA doesn't suggest a recommended daily limit for sugar, so it's hard to tell if this 65 grams in a bottle of soda is a little or a lot. But the World Health Organization recommends limiting sugar to just 5% of your total calories, or about 25 grams per day. So, 65 grams is well over twice that amount. But just what is sugar? What's the difference between glucose and fructose? Well, both are carbohydrates with the same chemical composition of carbon, hydrogen, and oxygen. But they have very different structures and behave quite differently in our bodies. Glucose is the best source of energy for nearly all organisms on Earth. It can be metabolized by all organs in the body. Fructose, on the other hand, is metabolized primarily in the liver, and when your liver gets overloaded with sweet, sweet fructose, the excess is metabolized to fat. Fresh fruits actually contain fructose, but it's naturally occurring and doesn't cause an overload because the fiber in fruit slows its absorption. This gives your liver the time it needs to do its job. It's sugar that makes cookies chewy and candy crunchy. It even turns bread crust a beautiful, golden brown. It's also a great preservative; it doesn't spoil or evaporate, so the foods it's added to are easier to store and ship long distances and tend to be cheaper. That's why sugar is hiding everywhere. Actually, it might be easier to list the foods that added sugar isn't hiding in, things like: vegetables, eggs, meats, fish, fruit, raw nuts, even your kitchen sink. Simply choosing water over soda, juices, and sports drinks is a great way to avoid hidden added sugar. At the very least, try to pay attention to food labels, so you can keep your sugar intake at a healthy level. Because in this game of hide and seek, every time you don't find added sugar, you win! |
How to use a semicolon | null | TED-Ed | It may seem like the semicolon is struggling with an identity crisis. It looks like a comma crossed with a period. Maybe that's why we toss these punctuation marks around like grammatical confetti. We're confused about how to use them properly. In fact, it's the semicolon's half-half status that makes it useful. It's stronger than a comma, and less final than a period. It fills the spaces in between, and for that reason, it has some specific and important tasks. For one, it can clarify ideas in a sentence that's already festooned with commas. "Semicolons: At first, they may seem frightening, then, they become enlightening, finally, you'll find yourself falling for these delightful punctuation marks." Even though the commas separate different parts of the sentence, it's easy to lose track of what belongs where. But then the semicolon edges in to the rescue. In list-like sentences, it can exert more force than commas do, cutting sentences into compartments and grouping items that belong together. The semicolon breaks things up, but it also builds connections. Another of its tasks is to link together independent clauses. These are sentences that can stand on their own, but when connected by semicolons, look and sound better because they're related in some way. "Semicolons were once a great mystery to me. I had no idea where to put them." Technically, there's nothing wrong with that. These two sentences can stand alone. But imagine they appeared in a long list of other sentences, all of the same length, each separated by periods. Things would get monotonous very fast. In that situation, semicolons bring fluidity and variation to writing by connecting related clauses. But as beneficial as they are, semicolons don't belong just anywhere. There are two main rules that govern their use. Firstly, unless they're being used in lists, semicolons should only connect clauses that are related in some way. You wouldn't use one here, for instance: "Semicolons were once a great mystery to me; I'd really like a sandwich." Periods work best here because these are two totally different ideas. A semicolon's job is to reunite two independent clauses that will benefit from one another's company because they refer to the same thing. Secondly, you'll almost never find a semicolon willingly stationed before coordinating conjunctions: the words, "and," "but," "for," "nor," "or," "so," and "yet." That's a comma's place, in fact. But a semicolon can replace a conjunction to shorten a sentence or to give it some variety. Ultimately, this underappreciated punctuation mark can give writing clarity, force, and style, all encompassed in one tiny dot and squiggle that's just waiting to be put in the right place. |
One of the most difficult words to translate... | null | TED-Ed | Which is the hardest word to translate in this sentence? "Know" is easy to translate. "Pep rally" doesn't have a direct analog in a lot of languages and cultures, but can be approximated. But the hardest word there is actually one of the smallest: "you." As simple as it seems, it's often impossible to accurately translate "you" without knowing a lot more about the situation where it's being said. To start with, how familiar are you with the person you're talking to? Many cultures have different levels of formality. A close friend, someone much older or much younger, a stranger, a boss. These all may be slightly different "you's." In many languages, the pronoun reflects these differences through what's known as the T–V distinction. In French, for example, you would say "tu" when talking to your friend at school, but "vous" when addressing your teacher. Even English once had something similar. Remember the old-timey "thou?" Ironically, it was actually the informal pronoun for people you're close with, while "you" was the formal and polite version. That distinction was lost when the English decided to just be polite all the time. But the difficulty in translating "you" doesn't end there. In languages like Hausa or Korana, the "you" form depends on the listener's gender. In many more, it depends on whether they are one or many, such as with German "Du" or "ihr." Even in English, some dialects use words like "y'all" or "youse" the same way. Some plural forms, like the French "vous" and Russian "Вы" are also used for a single person to show that the addressee is that much more important, much like the royal "we." And a few languages even have a specific form for addressing exactly two people, like Slovenian "vidva." If that wasn't complicated enough, formality, number, and gender can all come into play at the same time. In Spanish, "tú" is unisex informal singular, "usted" is unisex formal singular, "vosotros" is masculine informal plural, "vosotras" is feminine informal plural, and "ustedes" is the unisex formal plural. Phew! After all that, it may come as a relief that some languages often leave out the second person pronoun. In languages like Romanian and Portuguese, the pronoun can be dropped from sentences because it's clearly implied by the way the verbs are conjugated. And in languages like Korean, Thai, and Chinese, pronouns can be dropped without any grammatical hints. Speakers often would rather have the listener guess the pronoun from context than use the wrong one and risk being seen as rude. So if you're ever working as a translator and come across this sentence without any context: "You and you, no, not you, you, your job is to translate 'you' for yourselves" ... Well, good luck. And to the volunteer community who will be translating this video into multiple languages: Sorry about that! |
How quantum mechanics explains global warming | null | TED-Ed | You've probably heard that carbon dioxide is warming the Earth, but how does it work? Is it like the glass of a greenhouse or like an insulating blanket? Well, not entirely. The answer involves a bit of quantum mechanics, but don't worry, we'll start with a rainbow. If you look closely at sunlight separated through a prism, you'll see dark gaps where bands of color went missing. Where did they go? Before reaching our eyes, different gases absorbed those specific parts of the spectrum. For example, oxygen gas snatched up some of the dark red light, and sodium grabbed two bands of yellow. But why do these gases absorb specific colors of light? This is where we enter the quantum realm. Every atom and molecule has a set number of possible energy levels for its electrons. To shift its electrons from the ground state to a higher level, a molecule needs to gain a certain amount of energy. No more, no less. It gets that energy from light, which comes in more energy levels than you could count. Light consists of tiny particles called photons and the amount of energy in each photon corresponds to its color. Red light has lower energy and longer wavelengths. Purple light has higher energy and shorter wavelengths. Sunlight offers all the photons of the rainbow, so a gas molecule can choose the photons that carry the exact amount of energy needed to shift the molecule to its next energy level. When this match is made, the photon disappers as the molecule gains its energy, and we get a small gap in our rainbow. If a photon carries too much or too little energy, the molecule has no choice but to let it fly past. This is why glass is transparent. The atoms in glass do not pair well with any of the energy levels in visible light, so the photons pass through. So, which photons does carbon dioxide prefer? Where is the black line in our rainbow that explains global warming? Well, it's not there. Carbon dioxide doesn't absorb light directly from the Sun. It absorbs light from a totally different celestial body. One that doesn't appear to be emitting light at all: Earth. If you're wondering why our planet doesn't seem to be glowing, it's because the Earth doesn't emit visible light. It emits infared light. The light that our eyes can see, including all of the colors of the rainbow, is just a small part of the larger spectrum of electromagnetic radiation, which includes radio waves, microwaves, infrared, ultraviolet, x-rays, and gamma rays. It may seem strange to think of these things as light, but there is no fundamental difference between visible light and other electromagnetic radiation. It's the same energy, but at a higher or lower level. In fact, it's a bit presumptuous to define the term visible light by our own limitations. After all, infrared light is visible to snakes, and ultraviolet light is visible to birds. If our eyes were adapted to see light of 1900 megahertz, then a mobile phone would be a flashlight, and a cell phone tower would look like a huge lantern. Earth emits infrared radiation because every object with a temperature above absolute zero will emit light. This is called thermal radiation. The hotter an object gets, the higher frequency the light it emits. When you heat a piece of iron, it will emit more and more frequencies of infrared light, and then, at a temperature of around 450 degrees Celsius, its light will reach the visible spectrum. At first, it will look red hot. And with even more heat, it will glow white with all of the frequencies of visible light. This is how traditional light bulbs were designed to work and why they're so wasteful. 95% of the light they emit is invisible to our eyes. It's wasted as heat. Earth's infrared radiation would escape to space if there weren't greenhouse gas molecules in our atmophere. Just as oxygen gas prefers the dark red photons, carbon dioxide and other greenhouse gases match with infrared photons. They provide the right amount of energy to shift the gas molecules into their higher energy level. Shortly after a carbon dioxide molecule absorbs an infrared photon, it will fall back to its previous energy level, and spit a photon back out in a random direction. Some of that energy then returns to Earth's surface, causing warming. The more carbon dioxide in the atmosphere, the more likely that infrared photons will land back on Earth and change our climate. |
How optical illusions trick your brain | null | TED-Ed | Check this out: Here's a grid, nothing special, just a basic grid, very grid-y. But look closer, into this white spot at the center where the two central vertical and horizontal lines intersect. Look very closely. Notice anything funny about this spot? Yeah, nothing. But keep looking. Get weird and stare at it. Now, keeping your gaze fixed on this white spot, check what's happening in your peripheral vision. The other spots, are they still white? Or do they show weird flashes of grey? Now look at this pan for baking muffins. Oh, sorry, one of the cups is inverted. It pops up instead of dipping down. Wait, no spin the pan. The other five are domed now? Whichever it is, this pan's defective. Here's a photo of Abraham Lincoln, and here's one upside down. Nothing weird going on here. Wait, turn that upside down one right side up. What have they done to Abe? Those are just three optical illusions, images that seem to trick us. How do they work? Are magical things happening in the images themselves? While we could certainly be sneaking flashes of grey into the peripheral white spots of our animated grid, first off, we promise we aren't. You'll see the same effect with a grid printed on a plain old piece of paper. In reality, this grid really is just a grid. But not to your brain's visual system. Here's how it interprets the light information you call this grid. The white intersections are surrounded by relatively more white on all four sides than any white point along a line segment. Your retinal ganglion cells notice that there is more white around the intersections because they are organized to increase contrast with lateral inhibition. Better contrast means it's easier to see the edge of something. And things are what your eyes and brain have evolved to see. Your retinal ganglion cells don't respond as much at the crossings because there is more lateral inhibition for more white spots nearby compared to the lines, which are surrounded by black. This isn't just a defect in your eyes; if you can see, then optical illusions can trick you with your glasses on or with this paper or computer screen right up in your face. What optical illusions show us is the way your photo receptors and brain assemble visual information into the three-dimensional world you see around you, where edges should get extra attention because things with edges can help you or kill you. Look at that muffin pan again. You know what causes confusion here? Your brain's visual cortex operates on assumptions about the lighting of this image. It expects light to come from a single source, shining down from above. And so these shading patterns could only have been caused by light shining down on the sloping sides of a dome, or the bottom of a hole. If we carefully recreate these clues by drawing shading patterns, even on a flat piece of paper, our brain reflexively creates the 3D concave or convex shape. Now for that creepy Lincoln upside down face. Faces trigger activity in areas of the brain that have specifically evolved to help us recognize faces. Like the fusiform face area and others in the occipital and temporal lobes. It makes sense, too, we're very social animals with highly complex ways of interacting with each other. When we see faces, we have to recognize they are faces and figure out what they're expressing very quickly. And what we focus on most are the eyes and mouth. That's how we figure out if someone is mad at us or wants to be our friend. In the upside down Lincoln face, the eyes and mouth were actually right side up, so you didn't notice anything was off. But when we flipped the whole image over, the most important parts of the face, the eyes and mouth, were now upside down, and you realized something fishy was up. You realized your brain had taken a short cut and missed something. But your brain wasn't really being lazy, it's just very busy. So it spends cognitive energy as efficiently as possible, using assumptions about visual information to create a tailored, edited vision of the world. Imagine your brain calling out these edits on the fly: "Okay, those squares could be objects. Let's enhance that black-white contrast on the sides with lateral inhibition. Darken those corners! Dark grey fading into light grey? Assume overhead sunlight falling on a sloping curve. Next! Those eyes look like most eyes I've seen before, nothing weird going on here." See? Our visual tricks have revealed your brain's job as a busy director of 3D animation in a studio inside your skull, allocating cognitive energy and constructing a world on the fly with tried and mostly — but not always — true tricks of its own. |
How interpreters juggle two languages at once | null | TED-Ed | In 1956, during a diplomatic reception in Moscow, Soviet leader Nikita Khrushchev told Western Bloc ambassadors, "My vas pokhoronim!" His interpreter rendered that into English as, "We will bury you!" This statement sent shockwaves through the Western world, heightening the tension between the Soviet Union and the US who were in the thick of the Cold War. Some believe this incident alone set East/West relations back a decade. As it turns out, Khrushchev's remark was translated a bit too literally. Given the context, his words should have been rendered as, "We will live to see you buried," meaning that Communism would outlast Capitalism, a less threatening comment. Though the intended meaning was eventually clarified, the initial impact of Khrushchev's apparent words put the world on a path that could have led to nuclear armageddon. So now, given the complexities of language and cultural exchange, how does this sort of thing not happen all the time? Much of the answer lies with the skill and training of interpreters to overcome language barriers. For most of history, interpretation was mainly done consecutively, with speakers and interpreters making pauses to allow each other to speak. But after the advent of radio technology, a new simultaneous interpretations system was developed in the wake of World War II. In the simultaneous mode interpreters instantaneously translate a speaker's words into a microphone while he speaks. Without pauses, those in the audience can choose the language in which they want to follow. On the surface, it all looks seamless, but behind the scenes, human interpreters work incessantly to ensure every idea gets across as intended. And that is no easy task. It takes about two years of training for already fluent bilingual professionals to expand their vocabulary and master the skills necessary to become a conference interpreter. To get used to the unnatural task of speaking while they listen, students shadow speakers and repeat their every word exactly as heard in the same language. In time, they begin to paraphrase what is said, making stylistic adjustments as they go. At some point, a second language is introduced. Practicing in this way creates new neural pathways in the interpreter's brain, and the constant effort of reformulation gradually becomes second nature. Over time and through much hard work, the interpreter masters a vast array of tricks to keep up with speed, deal with challenging terminology, and handle a multitude of foreign accents. They may resort to acronyms to shorten long names, choose generic terms over specific, or refer to slides and other visual aides. They can even leave a term in the original language, while they search for the most accurate equivalent. Interpreters are also skilled at keeping aplomb in the face of chaos. Remember, they have no control over who is going to say what, or how articulate the speaker will sound. A curveball can be thrown at any time. Also, they often perform to thousands of people and in very intimidating settings, like the UN General Assembly. To keep their emotions in check, they carefully prepare for an assignment, building glossaries in advance, reading voraciously about the subject matter, and reviewing previous talks on the topic. Finally, interpreters work in pairs. While one colleague is busy translating incoming speeches in real time, the other gives support by locating documents, looking up words, and tracking down pertinent information. Because simultaneous interpretation requires intense concentration, every 30 minutes, the pair switches roles. Success is heavily dependent on skillful collaboration. Language is complex, and when abstract or nuanced concepts get lost in translation, the consequences may be catastrophic. As Margaret Atwood famously noted, "War is what happens when language fails." Conference interpreters of all people are aware of that and work diligently behind the scenes to make sure it never does. |
Why do women have periods? | null | TED-Ed | A handful of species on Earth share a seemingly mysterious trait: a menstrual cycle. We're one of the select few. Monkeys, apes, bats, humans, and possibly elephant shrews are the only mammals on Earth that menstruate. We also do it more than any other animal, even though its a waste of nutrients and can be a physical inconvenience. So where's the sense in this uncommon biological process? The answer begins with pregnancy. During this process, the body's resources are cleverly used to shape a suitable environment for a fetus, creating an internal haven for a mother to nurture her growing child. In this respect, pregnancy is awe-inspiring, but that's only half the story. The other half reveals that pregnancy places a mother and her child at odds. As for all living creatures, the human body evolved to promote the spread of its genes. For the mother, that means she should try to provide equally for all her offspring. But a mother and her fetus don't share exactly the same genes. The fetus inherits genes from its father, as well, and those genes can promote their own survival by extracting more than their fair share of resources from the mother. This evolutionary conflict of interests places a woman and her unborn child in a biological tug-of-war that plays out inside the womb. One factor contributing to this internal tussle is the placenta, the fetal organ that connects to the mother's blood supply and nourishes the fetus while it grows. In most mammals, the placenta is confined behind a barrier of maternal cells. This barrier lets the mother control the supply of nutrients to the fetus. But in humans and a few other species, the placenta actually penetrates right into the mother's circulatory system to directly access her blood stream. Through its placenta, the fetus pumps the mother's arteries with hormones that keep them open to provide a permanent flow of nutrient-rich blood. A fetus with such unrestricted access can manufacture hormones to increase the mother's blood sugar, dilate her arteries, and inflate her blood pressure. Most mammal mothers can expel or reabsorb embryos if required, but in humans, once the fetus is connected to the blood supply, severing that connection can result in hemorrhage. If the fetus develops poorly or dies, the mother's health is endangered. As it grows, a fetus's ongoing need for resources can cause intense fatigue, high blood pressure, and conditions like diabetes and preeclampsia. Because of these risks, pregnancy is always a huge, and sometimes dangerous, investment. So it makes sense that the body should screen embryos carefully to find out which ones are worth the challenge. This is where menstruation fits in. Pregnancy starts with a process called implantation, where the embryo embeds itself in the endometrium that lines the uterus. The endometrium evolved to make implantation difficult so that only the healthy embryos could survive. But in doing so, it also selected for the most vigorously invasive embryos, creating an evolutionary feedback loop. The embryo engages in a complex, exquisitely timed hormonal dialogue that transforms the endometrium to allow implantation. What happens when an embryo fails the test? It might still manage to attach, or even get partly through the endometrium. As it slowly dies, it could leave its mother vulnerable to infection, and all the time, it may be emitting hormonal signals that disrupt her tissues. The body avoids this problem by simply removing every possible risk. Each time ovulation doesn't result in a healthy pregnancy, the womb gets rid of its endometrial lining, along with any unfertilized eggs, sick, dying, or dead embryos. That protective process is known as menstruation, leading to the period. This biological trait, bizarre as it may be, sets us on course for the continuation of the human race. |
The real story behind Archimedes' Eureka! | null | TED-Ed | When you think of Archimedes' "Eureka!" moment, you probably think of this. As it turns out, it may have been more like this. In the third century BC, Hieron, king of the Sicilian city of Syracuse, chose Archimedes to supervise an engineering project of unprecedented scale. Hieron commissioned a sailing vessel 50 times bigger than a standard ancient warship, named the Syracusia after his city. Hieron wanted to construct the largest ship ever, which was destined to be given as a present for Egypt's ruler, Ptolemy. But could a boat the size of a palace possibly float? In Archimedes's day, no one had attempted anything like this. It was like asking, "Can a mountain fly?" King Hieron had a lot riding on that question. Hundreds of workmen were to labor for years on constructing the Syracusia out of beams of pine and fir from Mount Etna, ropes from hemp grown in Spain, and pitch from France. The top deck, on which eight watchtowers were to stand, was to be supported not by columns, but by vast wooden images of Atlas holding the world on his shoulders. On the ship's bow, a massive catapult would be able to fire 180 pound stone missiles. For the enjoyment of its passengers, the ship was to feature a flower-lined promenade, a sheltered swimming pool, and bathhouse with heated water, a library filled with books and statues, a temple to the goddess Aphrodite, and a gymnasium. And just to make things more difficult for Archimedes, Hieron intended to pack the vessel full of cargo: 400 tons of grain, 10,000 jars of pickled fish, 74 tons of drinking water, and 600 tons of wool. It would have carried well over a thousand people on board, including 600 soldiers. And it housed 20 horses in separate stalls. To build something of this scale, only for that to sink on its maiden voyage? Well, let's just say that failure wouldn't have been a pleasant option for Archimedes. So he took on the problem: will it sink? Perhaps he was sitting in the bathhouse one day, wondering how a heavy bathtub can float, when inspiration came to him. An object partially immersed in a fluid is buoyed up by a force equal to the weight of the fluid displaced by the object. In other words, if a 2,000 ton Syracusia displaced exactly 2,000 tons of water, it would just barely float. If it displaced 4,000 tons of water, it would float with no problem. Of course, if it only displaced 1,000 tons of water, well, Hieron wouldn't be too happy. This is the law of buoyancy, and engineers still call it Archimedes' Principle. It explains why a steel supertanker can float as easily as a wooden rowboat or a bathtub. If the weight of water displaced by the vessel below the keel is equivalent to the vessel's weight, whatever is above the keel will remain afloat above the waterline. This sounds a lot like another story involving Archimedes and a bathtub, and it's possible that's because they're actually the same story, twisted by the vagaries of history. The classical story of Archimedes' Eureka! and subsequent streak through the streets centers around a crown, or corona in Latin. At the core of the Syracusia story is a keel, or korone in Greek. Could one have been mixed up for the other? We may never know. On the day the Syracusia arrived in Egypt on its first and only voyage, we can only imagine how residents of Alexandria thronged the harbor to marvel at the arrival of this majestic, floating castle. This extraordinary vessel was the Titanic of the ancient world, except without the sinking, thanks to our pal, Archimedes. |
What "Machiavellian" really means | null | TED-Ed | From Shakespeare’s plays to modern TV dramas, the unscrupulous schemer for whom the ends always justify the means has become a familiar character type we love to hate. So familiar, in fact, that for centuries we’ve had a single word to describe such characters: Machiavellian. But is it possible that we’ve been using that word wrong this whole time? The early 16th century statesman Niccoló Machiavelli wrote many works of history, philosophy, and drama. But his lasting notoriety comes from a brief political essay known as The Prince, framed as advice to current and future monarchs. Machiavelli wasn’t the first to do this– in fact there was an entire tradition of works known as “mirrors for princes” going back to antiquity. But unlike his predecessors, Machiavelli didn’t try to describe an ideal government or exhort his audience to rule justly and virtuously. Instead, he focused on the question of power– how to acquire it, and how to keep it. And in the decades after it was published, The Prince gained a diabolical reputation. During the European Wars of Religion, both Catholics and Protestants blamed Machiavelli for inspiring acts of violence and tyranny committed by their opponents. By the end of the century, Shakespeare was using “Machiavel” to denote an amoral opportunist, leading directly to our popular use of “Machiavellian” as a synonym for manipulative villainy. At first glance, The Prince’s reputation as a manual for tyranny seems well-deserved. Throughout, Machiavelli appears entirely unconcerned with morality, except insofar as it’s helpful or harmful to maintaining power. For instance, princes are told to consider all the atrocities necessary to seize power, and to commit them in a single stroke to ensure future stability. Attacking neighboring territories and oppressing religious minorities are mentioned as effective ways of occupying the public. Regarding a prince’s personal behavior, Machiavelli advises keeping up the appearance of virtues such as honesty or generosity, but being ready to abandon them as soon as one’s interests are threatened. Most famously, he notes that for a ruler, “it is much safer to be feared than loved.” The tract even ends with an appeal to Lorenzo de’ Medici, the recently installed ruler of Florence, urging him to unite the fragmented city-states of Italy under his rule. Many have justified Machiavelli as motivated by unsentimental realism and a desire for peace in an Italy torn by internal and external conflict. According to this view, Machiavelli was the first to understand a difficult truth: the greater good of political stability is worth whatever unsavory tactics are needed to attain it. The philosopher Isaiah Berlin suggested that rather than being amoral, The Prince hearkens back to ancient Greek morality, placing the glory of the state above the Christian ideal of individual salvation. But what we know about Machiavelli might not fit this picture. The author had served in his native Florence for 14 years as a diplomat, staunchly defending its elected republican government against would-be monarchs. When the Medici family seized power, he not only lost his position, but was even tortured and banished. With this in mind, it’s possible to read the pamphlet he wrote from exile not as a defense of princely rule, but a scathing description of how it operates. Indeed, Enlightenment figures like Spinoza saw it as warning free citizens of the various ways in which they can be subjugated by aspiring rulers. In fact, both readings might be true. Machiavelli may have written a manual for tyrannical rulers, but by sharing it, he also revealed the cards to those who would be ruled. In doing so, he revolutionized political philosophy, laying the foundations for Hobbes and future thinkers to study human affairs based on their concrete realities rather than preconceived ideals. Through his brutal and shocking honesty, Machiavelli sought to shatter popular delusions about what power really entails. And as he wrote to a friend shortly before his death, he hoped that people would “learn the way to Hell in order to flee from it." |
What it's like to have Tourette's -- and how music gives me back control | {0: 'Esha Alwani\'s message to the world is simple: "Music is healing therapy, and we need to make a place for it in our lives."'} | TED-Ed Weekend | I'd like you to imagine what it would feel like if, for two whole minutes, your left arm was continuously flapping, your eyes were constantly rolling, your jaw was clenching so hard that it felt like your teeth were about to break, and every ten seconds, you were forced to let out a loud, high-pitched screech. (Tic) This is how I lived at the young age of six, every waking moment, seven days a week. (Tic) And these were only some of my symptoms. When these symptoms surfaced, my life literally changed overnight. I could no longer go to school, see my friends or even eat out, because my tics would attract the attention of everyone in the room. In search for a cure, we flew to New York to meet with the best pediatric neuropsychologist my parents could find. (Tic) But the doctor did not give us the easy remedy we had hoped for. Instead, she diagnosed me with an incurable neurological disorder, Tourette syndrome. Oftentimes, medication can be an essential and valuable part of many treatment processes. But in my case, the drugs only made things worse. One drug put me in a wheelchair, because my legs had gotten so numb that I couldn't move them. Another one caused me to hallucinate. I would see green people running after me, threatening to boil me in a pot and drink me as soup. And it was really scary. We tried drug after drug to find something that would bring me some sort of relief. But every single attempt just ended up making things worse. It is estimated that in 2013 in the United States alone, the prescription drug expenditure to treat neurological conditions and mental illness was about 89 billion dollars annually. But imagine if there were a way to treat these conditions without a price or without side effects. Imagine if your doctor prescribed you a daily dose of music. I'm here today to share with you my personal experience with music and the effect that it had on my neurological disorder. (Tic) Tourette syndrome is essentially a series of involuntary movements and sounds, known as tics. The best way for me to really describe what it's like to have Tourette syndrome is something I'm sure you're all very familiar with — the hiccups. You can try to stop yourself from the act. You can hold your breath and count to 10, or drink water upside down, but there is just nothing you can do about it until the sensation passes and the hiccups have taken their course. I often lay on my bedroom floor after an attack of tics, feeling exhausted and in despair. (Tic) My equally desperate mother would attempt to soothe me and herself by putting on some music. She would play peaceful music to soothe our aching hearts. And we'd lie together on the floor and allow the beat of the drums to uplift us. And as the rhythms and the tunes unfolded, our spirits would rise, our moods would be lighter, and we would be rejuvenated. (Tic) Very soon, and rather unknowingly, I became an addict of this newfound drug. When I found myself slipping into my bouts of sadness and self-pity, I would rush to the 88 keys of my piano, knowing in my heart that the tones and rhythms from each one of those keys would soon set me free. At the time, I didn't realize how much music was helping me. It was just something I did by default. When I wrote my songs, it wasn't to impress anybody. It was just a release. But the more I played, the less my symptoms surfaced, and the intensity of my attacks reduced. So I became curious as to how these songs were soothing my symptoms. And I wondered if there were any other cases of medicinal music. So I began to search. I found that there was a highly successful US congresswoman, Gabby Giffords, who was shot in the head. She lost her ability to speak. Because the ability to speak and the ability to sing lay in two separate parts of the brain, her doctors brought in music therapists to work with her. The therapists encouraged her to sing her thoughts, since she was incapable of speaking them. And through this technique, the congresswoman was finally able to regain her speech. Music helped heal Gabby Giffords. Scientists have found that music causes our brains to release a natural painkiller known as oxytocin and a feel-good chemical, dopamine. Dopamine is essential for a healthy nervous system and strongly impacts emotional health. Music also affects our heart rate, breathing and pulse rate, as it stimulates blood flow. In addition, it lowers our cortisol levels, thus reducing anxiety, which is a common stimulant for neurological symptoms. In our lifetimes, we are all going to know someone with a neurological disorder. If it's not a family member — (Tic) it could be a friend or a coworker. Please help me spread this message: music has the ability to uplift our lives and heal us from within. I still have Tourette syndrome. I deal with it every day, every hour. I'm going to deal with it for the rest of my life. And that means that I have to frequently excuse myself from my classroom, because my verbal tics can be extremely distracting. That means that sometimes when I wink my eyes involuntarily, the guy sitting opposite from me thinks I'm flirting with him, when I'm really not. (Laughter) And I have to tell him, "Sorry — I wasn't trying to flirt." But the most amazing thing is that when I sing, play music and even just listen to music, I don't tic. I've been onstage numerous times in highly stressful situations, with thousands of people watching me. And while I do tic before my performance — (Tic) when the music starts, the tics take a back seat. So I may have written my own lyrics and composed my own music. But in reality, I've realized it was the music that composed me. Thank you. (Applause) (Tic) (Music) (Singing) I think I took my mask off too soon 'Cause you were there and then you were not I think I pushed it all onto you I should have dragged it out dragged it out I think that maybe each time I lose a bit of myself I put it back on Just to fake it till I break my own heart in two And oh I wanted you to know the real me And take it seriously But now I'm not loving you I'm not loving you I'm not loving you I thought I could trust you But you're running away from me and my mask I'm not loving you I'm not loving you I'm not loving you Right now I think I took my mask off too soon Because you screamed when I pulled it off You told me you were unprepared And like that just like that I think that maybe this time it hurt more than it ever has before I think maybe this blow I took was a little more A little more And oh I wanted you to know the real me And take it seriously But now I’m not loving you I'm not loving you I'm not loving you I thought I could trust you But you're running away from me and my mask I'm not loving you I'm not loving you I'm not loving you Right now (Applause) |
A brief history of dogs | null | TED-Ed | Since their emergence over 200,000 years ago, modern humans have established homes and communities all over the planet. But they didn’t do it alone. Whatever corner of the globe you find homo sapiens in today, you’re likely to find another species nearby: Canis lupus familiaris. Whether they’re herding, hunting, sledding, or slouching the sheer variety of domestic dogs is staggering. But what makes the story of man’s best friend so surprising is that they all evolved from a creature often seen as one of our oldest rivals: Canis lupus, or the gray wolf. When our Paleolithic ancestors first settled Eurasia roughly 100,000 years ago, wolves were one of their main rivals at the top of the food chain. Able to exert over 300 lbs. of pressure in one bone-crushing bite and sniff out prey more than a mile away, these formidable predators didn’t have much competition. Much like human hunter-gatherers, they lived and hunted in complex social groups consisting of a few nuclear families, and used their social skills to cooperatively take down larger creatures. Using these group tactics, they operated as effective persistence hunters, relying not on outrunning their prey, but pursuing it to the point of exhaustion. But when pitted against the similar strengths of their invasive new neighbors, wolves found themselves at a crossroads. For most packs, these bourgeoning bipeds represented a serious threat to their territory. But for some wolves, especially those without a pack, human camps offered new opportunities. Wolves that showed less aggression towards humans could come closer to their encampments, feeding on leftovers. And as these more docile scavengers outlasted their aggressive brethren, their genetic traits were passed on, gradually breeding tamer wolves in areas near human populations. Over time humans found a multitude of uses for these docile wolves. They helped to track and hunt prey, and might have served as sentinels to guard camps and warn of approaching enemies. Their similar social structure made it easy to integrate with human families and learn to understand their commands. Eventually they moved from the fringes of our communities into our homes, becoming humanity’s first domesticated animal. The earliest of these Proto-Dogs or Wolf-Dogs, seem to have appeared around 33,000 years ago, and would not have looked all that different from their wild cousins. They were primarily distinguished by their smaller size and a shorter snout full of comparatively smaller teeth. But as human cultures and occupations became more diverse and specialized, so did our friends. Short stocky dogs to herd livestock by nipping their heels; elongated dogs to flush badgers and foxes out of burrows; thin and sleek dogs for racing; and large, muscular dogs for guard duty. With the emergence of kennel clubs and dog shows during England’s Victorian era, these dog types were standardized into breeds, with many new ones bred purely for appearance. Sadly, while all dog breeds are the product of artificial selection, some are healthier than others. Many of these aesthetic characteristics come with congenital health problems, such as difficulty breathing or being prone to spinal injuries. Humanity’s longest experiment in controlled evolution has had other side effects as well. Generations of selection for tameness have favored more juvenile and submissive traits that were pleasing to humans. This phenomenon of selecting traits associated with youth is known as neoteny, and can be seen in many domestic animals. Thousands of years of co-evolution may even have bonded us chemically. Not only can canines understand our emotions and body language, but when dogs and humans interact, both our bodies release oxytocin; a hormone commonly associated with feelings of love and protectiveness. It might be difficult to fathom how every Pomeranian, Chihuahua, and Poodle are descended from fierce wolves. But the diversity of breeds today is the result of a relationship that precedes cities, agriculture, and even the disappearance of our Neanderthal cousins. And it’s heartening to know that given enough time, even our most dangerous rivals can become our fiercest friends. |
Cómo un doctor de astronautas capacita al cuerpo para el espacio | {0: 'Víctor Demaría Pesce es marplatense, médico, dedicado a la investigación científica. Desde hace muchos años vive en Paris y trabaja en el Centro Europeo de Astronautas. Es especializado en estudiar la interface entre el hombre y los ambientes extremos (altitud, micro-gravedad, temperaturas extremas, grandes profundidades). Además es marino, buzo, espeleólogo y aviador. Tomó una parte activa en los programas espaciales de los Estados Unidos, de Europa y de Rusia. Sus experimentos científicos se incluyeron en varios vuelos de los transbordadores estadounidenses, en la estación Mir y en vuelos de las cápsulas Soyuz y Cosmos.'} | TEDxRiodelaPlata | Do you remember when we were children, when the adults without fail, to show us they were interested in us, they would ask us the question: "And you, what do you want to be when you grow up?" And in general, we said whatever came to our heads. I wanted to be an astronaut. But that didn't work out. I ended up becoming a doctor, a neurologist and a researcher. And the question I always asked myself: What are the limits of human adaptation to extreme environments such as high or low temperatures, high heights, extreme depth, even outer space? As you can imagine, I don't have any patients, because you need to be in great health to be able to face such an extreme environment. This theme, became the research focus that I have followed throughout my whole career in science. My work place? The European Astronaut Centre of the European Space Agency. Who are my patients? The team of European astronauts. By the way, do you know that there are astronauts in space right now? Yes or no? Yes! Since 2001, there has been a permanent presence of humans in space. Six astronauts from various nationalities spend six months in the International Space Station. Every six months, there are three that come down and three that go up. The last three actually just arrived yesterday to the ISS station. The ISS, or what we call it, the International Space Station, is a grand scientific laboratory. It it right here, in a "suburb" of the Earth. It's is flying at 400 kilometers away at a velocity of 17,400 mph. The astronauts go 16 times around the Earth in 24 hours. At this velocity, instead of in 14 hours, tomorrow I could go home to my house in Paris in 24 minutes. It would be awesome! (Laughter) The astronauts — Who are the astronauts? They are professionals, high level technicians. They are experimenters, because they perform the scientific experiments that we doctors and researches design. They are also the subjects of our experiments, because we do experiments on them. The question that you will ask, of course is: if the astronauts are all healthy, why do they need a doctor? They actually do, because my work within the research, like those of my colleagues, is to enable the astronauts to overcome their fiscal physical and psychological problems so they can live and work in space. An environment for which evolution didn't prepare us. On the Earth there are two fundamental factors; the force of gravity that has conditioned our entire anatomy, the rotation of Earth and the way it alternates between light and darkness, that has conditioned all of our physiology. The force of gravity has conditioned our anatomy giving us our symmetrical body, more or less, our sense of balance, the skeleton, our muscle mass, all of this is conditioned by gravity and the fight against it. There is no gravity in space, so what will happen? They will have balance problems, they will have decalcification. The skeleton that's up there will have a loss of muscle mass. So... we have designed a series of physical exercises with very precise protocols which take into account all of the sectors of the body, so they can stay in shape. Because, in addition, the astronauts aren't weighed down, so they stretch, growing about one inch. And this produces pain. Short people don't have expectations, because when you return, you shrink — (Laughter) So, at this moment, we are all working to ease this type of pain, creating a "super skin suit", that is the suit that the astronauts use here, that we tried for the first time three months ago. I was telling you about the rotation of the Earth, and the alternating day and night. When this alternation is missing, all of our physiology is affected. And, of course, that together with all of the circadian rhythms and all of the physiological variables. From the first flights to space, we learned that the astronauts didn't sleep well. The quantity and quality were altered. The body temperature as well. Sleep, temperature, metabolism, nutrition — because with all of these metabolic changes that I was mentioning, nutrition is affected. Above all, the environment of the space station, with the long working hours from 8 am to 10 pm, so they can execute all of the protocols, that we give them to do. And also the constant noise of ventilation, up to 60 to 70 decibels to circulate the air. The light that isn't that bright. However, in 30 years of research, we have been able to improve a few of the working conditions. The simple things: a comfortable sleeping bag, which produces in space the same pleasing sensation that we feel when we go to lie down and are between the sheets. Also, the nutrition: It's not only to cover nutritional and metabolic needs — because you have to be really hungry to want to eat this — (Laughter) But also, to take well into account the psychological aspect and the taste. That's why the astronaut in red, Luca Parmitano, who is a friend of mine, brought to the station his Mom's lasagna, to share with the entire crew. That's a really special moment for them. And we realized that we as doctors and researchers, have made some progress. At this time, we are able to enable astronauts to live and work for a period of time in space and bring them back to Earth, all in all, in good health. I see a lot of young people in this room, that are very lucky because at this time, we are starting a new era in space exploration. I told you that the Space Station was in the suburbs. We are returning to the Moon now, on our way to Mars. Did you realize this? Only 12 men have had the luck to walk and work on the Moon for a few hours or almost three days. The highlight images that you are seeing right now, are not science fiction. Our daily work at this time, from what we are seeing is going to happen: the first construction robots will recover the lunar dust, the regolith, to build the first shelter — starting in 2025. After the first building is done, three years after that, man will arrive. First, for a few days. And later, they will stay for a few months. This is very fast in the video — it will take 3 months to do it. There they will have their little house. For us it is a huge challenge. We have to anticipate new training protocols so the astronauts, when they are walking on the Moon, will be ready for anything that can happen. We also have to have or engineer health monitoring systems to be able to check on them, to detect any problems, and to be able to diagnose them. And if a problem exists, we have to intervene therapeutically, without any doctor close by. That is something very important to us. And this trip to the Moon is only the first chapter, to continue on to Mars, the target. Did you know? After many years of working in the space field, at NASA and the European Space Agency, I am starting to realize with my colleges, that at this time, we are facing the same type of problems that our predecessors had, the doctors for the Apollo program. The Apollo program, in my youth, like all of my generation, we dreamed about this program. And inevitably, this project to put a man on the Moon, influenced my choice and professional path. And now this program is still relevant. It's because of this, above all for the young people, I want to tell you that I really hope that you can dream and that you can live by it. In this short time that I was here with you, I hope that I have passed on a little of my enthusiasm and passion. Thank you very much. (Applause) |
A new class of drug that could prevent depression and PTSD | {0: 'TED Fellow Dr. Rebecca Brachman is a pioneer in the field of preventative psychopharmacology, developing drugs to enhance stress resilience and prevent mental illness.'} | TED2017 | So the first antidepressants were made from, of all things, rocket fuel, left over after World War II. Which is fitting, seeing as today, one in five soldiers develop depression, or post-traumatic stress disorder or both. But it's not just soldiers that are at high risk for these diseases. It's firefighters, ER doctors, cancer patients, aid workers, refugees — anyone exposed to trauma or major life stress. And yet, despite how commonplace these disorders are, our current treatments, if they work at all, only suppress symptoms. In 1798, when Edward Jenner discovered the first vaccine — it happened to be for smallpox — he didn't just discover a prophylactic for a disease, but a whole new way of thinking: that medicine could prevent disease. However, for over 200 years, this prevention was not believed to extend to psychiatric diseases. Until 2014, when my colleague and I accidentally discovered the first drugs that might prevent depression and PTSD. We discovered the drugs in mice, and we're currently studying whether they work in humans. And these preventative psychopharmaceuticals are not antidepressants. They are a whole new class of drug. And they work by increasing stress resilience, so let's call them resilience enhancers. So think back to a stressful time that you've since recovered from. Maybe a breakup or an exam, you missed a flight. Stress resilience is the active biological process that allows us to bounce back after stress. Similar to if you have a cold and your immune system fights it off. And insufficient resilience in the face of a significant enough stressor, can result in a psychiatric disorder, such as depression. In fact, most cases of major depressive disorder are initially triggered by stress. And from what we've seen so far in mice, resilience enhancers can protect against purely biological stressors, like stress hormones, and social and psychological stressors, like bullying and isolation. So here is an example where we gave mice three weeks of high levels of stress hormones. So, in other words, a biological stressor without a psychological component. And this causes depressive behavior. And if we give three weeks of antidepressant treatment beforehand, it has no beneficial effects. But a single dose of a resilience enhancer given a week before completely prevents the depressive behavior. Even after three weeks of stress. This is the first time a drug has ever been shown to prevent the negative effects of stress. Depression and PTSD are chronic, often lifelong, clinical diseases. They also increase the risk of substance abuse, homelessness, heart disease, Alzheimer's, suicide. The global cost of depression alone is over three trillion dollars per year. But now, imagine a scenario where we know someone is predictively at high risk for exposure to extreme stress. Say, a red cross volunteer going into an earthquake zone. In addition to the typhoid vaccine, we could give her a pill or an injection of a resilience enhancer before she leaves. So when she is held at gunpoint by looters or worse, she would at least be protected against developing depression or PTSD after the fact. It won't prevent her from experiencing the stress, but it will allow her to recover from it. And that's what's revolutionary here. By increasing resiliency, we can dramatically reduce her susceptibility to depression and PTSD, possibly saving her from losing her job, her home, her family or even her life. After Jenner discovered the smallpox vaccine, a lot of other vaccines rapidly followed. But it was over 150 years before a tuberculosis vaccine was widely available. Why? In part because society believed that tuberculosis made people more sensitive and creative and empathetic. And that it was caused by constitution and not biology. And similar things are still said today about depression. And just as Jenner's discovery opened the door for all of the vaccines that followed after, the drugs we've discovered open the possibility of a whole new field: preventative psychopharmacology. But whether that's 15 years away, or 150 years away, depends not just on the science, but on what we as a society choose to do with it. Thank you. (Applause) |
To detect diseases earlier, let's speak bacteria's secret language | {0: "Fatima AlZahra'a Alatraktchi invented a method to spy on the social behavior and communication of bacteria."} | TEDxAarhus | You don't know them. You don't see them. But they're always around, whispering, making secret plans, building armies with millions of soldiers. And when they decide to attack, they all attack at the same time. I'm talking about bacteria. (Laughter) Who did you think I was talking about? Bacteria live in communities just like humans. They have families, they talk, and they plan their activities. And just like humans, they trick, deceive, and some might even cheat on each other. What if I tell you that we can listen to bacterial conversations and translate their confidential information into human language? And what if I tell you that translating bacterial conversations can save lives? I hold a PhD in nanophysics, and I've used nanotechnology to develop a real-time translation tool that can spy on bacterial communities and give us recordings of what bacteria are up to. Bacteria live everywhere. They're in the soil, on our furniture and inside our bodies. In fact, 90 percent of all the live cells in this theater are bacterial. Some bacteria are good for us; they help us digest food or produce antibiotics. And some bacteria are bad for us; they cause diseases and death. To coordinate all the functions bacteria have, they have to be able to organize, and they do that just like us humans — by communicating. But instead of using words, they use signaling molecules to communicate with each other. When bacteria are few, the signaling molecules just flow away, like the screams of a man alone in the desert. But when there are many bacteria, the signaling molecules accumulate, and the bacteria start sensing that they're not alone. They listen to each other. In this way, they keep track of how many they are and when they're many enough to initiate a new action. And when the signaling molecules have reached a certain threshold, all the bacteria sense at once that they need to act with the same action. So bacterial conversation consists of an initiative and a reaction, a production of a molecule and the response to it. In my research, I focused on spying on bacterial communities inside the human body. How does it work? We have a sample from a patient. It could be a blood or spit sample. We shoot electrons into the sample, the electrons will interact with any communication molecules present, and this interaction will give us information on the identity of the bacteria, the type of communication and how much the bacteria are talking. But what is it like when bacteria communicate? Before I developed the translation tool, my first assumption was that bacteria would have a primitive language, like infants that haven't developed words and sentences yet. When they laugh, they're happy; when they cry, they're sad. Simple as that. But bacteria turned out to be nowhere as primitive as I thought they would be. A molecule is not just a molecule. It can mean different things depending on the context, just like the crying of babies can mean different things: sometimes the baby is hungry, sometimes it's wet, sometimes it's hurt or afraid. Parents know how to decode those cries. And to be a real translation tool, it had to be able to decode the signaling molecules and translate them depending on the context. And who knows? Maybe Google Translate will adopt this soon. (Laughter) Let me give you an example. I've brought some bacterial data that can be a bit tricky to understand if you're not trained, but try to take a look. (Laughter) Here's a happy bacterial family that has infected a patient. Let's call them the Montague family. They share resources, they reproduce, and they grow. One day, they get a new neighbor, bacterial family Capulet. (Laughter) Everything is fine, as long as they're working together. But then something unplanned happens. Romeo from Montague has a relationship with Juliet from Capulet. (Laughter) And yes, they share genetic material. (Laughter) Now, this gene transfer can be dangerous to the Montagues that have the ambition to be the only family in the patient they have infected, and sharing genes contributes to the Capulets developing resistance to antibiotics. So the Montagues start talking internally to get rid of this other family by releasing this molecule. (Laughter) And with subtitles: [Let us coordinate an attack.] (Laughter) Let's coordinate an attack. And then everybody at once responds by releasing a poison that will kill the other family. [Eliminate!] (Laughter) The Capulets respond by calling for a counterattack. [Counterattack!] And they have a battle. This is a video of real bacteria dueling with swordlike organelles, where they try to kill each other by literally stabbing and rupturing each other. Whoever's family wins this battle becomes the dominant bacteria. So what I can do is to detect bacterial conversations that lead to different collective behaviors like the fight you just saw. And what I did was to spy on bacterial communities inside the human body in patients at a hospital. I followed 62 patients in an experiment, where I tested the patient samples for one particular infection, without knowing the results of the traditional diagnostic test. Now, in bacterial diagnostics, a sample is smeared out on a plate, and if the bacteria grow within five days, the patient is diagnosed as infected. When I finished the study and I compared the tool results to the traditional diagnostic test and the validation test, I was shocked. It was far more astonishing than I had ever anticipated. But before I tell you what the tool revealed, I would like to tell you about a specific patient I followed, a young girl. She had cystic fibrosis, a genetic disease that made her lungs susceptible to bacterial infections. This girl wasn't a part of the clinical trial. I followed her because I knew from her medical record that she had never had an infection before. Once a month, this girl went to the hospital to cough up a sputum sample that she spit in a cup. This sample was transferred for bacterial analysis at the central laboratory so the doctors could act quickly if they discovered an infection. And it allowed me to test my device on her samples as well. The first two months I measured on her samples, there was nothing. But the third month, I discovered some bacterial chatter in her sample. The bacteria were coordinating to damage her lung tissue. But the traditional diagnostics showed no bacteria at all. I measured again the next month, and I could see that the bacterial conversations became even more aggressive. Still, the traditional diagnostics showed nothing. My study ended, but a half a year later, I followed up on her status to see if the bacteria only I knew about had disappeared without medical intervention. They hadn't. But the girl was now diagnosed with a severe infection of deadly bacteria. It was the very same bacteria my tool discovered earlier. And despite aggressive antibiotic treatment, it was impossible to eradicate the infection. Doctors deemed that she would not survive her 20s. When I measured on this girl's samples, my tool was still in the initial stage. I didn't even know if my method worked at all, therefore I had an agreement with the doctors not to tell them what my tool revealed in order not to compromise their treatment. So when I saw these results that weren't even validated, I didn't dare to tell because treating a patient without an actual infection also has negative consequences for the patient. But now we know better, and there are many young boys and girls that still can be saved because, unfortunately, this scenario happens very often. Patients get infected, the bacteria somehow don't show on the traditional diagnostic test, and suddenly, the infection breaks out in the patient with severe symptoms. And at that point, it's already too late. The surprising result of the 62 patients I followed was that my device caught bacterial conversations in more than half of the patient samples that were diagnosed as negative by traditional methods. In other words, more than half of these patients went home thinking they were free from infection, although they actually carried dangerous bacteria. Inside these wrongly diagnosed patients, bacteria were coordinating a synchronized attack. They were whispering to each other. What I call "whispering bacteria" are bacteria that traditional methods cannot diagnose. So far, it's only the translation tool that can catch those whispers. I believe that the time frame in which bacteria are still whispering is a window of opportunity for targeted treatment. If the girl had been treated during this window of opportunity, it might have been possible to kill the bacteria in their initial stage, before the infection got out of hand. What I experienced with this young girl made me decide to do everything I can to push this technology into the hospital. Together with doctors, I'm already working on implementing this tool in clinics to diagnose early infections. Although it's still not known how doctors should treat patients during the whispering phase, this tool can help doctors keep a closer eye on patients in risk. It could help them confirm if a treatment had worked or not, and it could help answer simple questions: Is the patient infected? And what are the bacteria up to? Bacteria talk, they make secret plans, and they send confidential information to each other. But not only can we catch them whispering, we can all learn their secret language and become ourselves bacterial whisperers. And, as bacteria would say, "3-oxo-C12-aniline." (Laughter) (Applause) Thank you. |
A short history of trans people's long fight for equality | {0: 'Samy Nour Younes is a trans actor and activist who highlights the diversity of the trans experience -- not just in their struggles, but also in their triumphs.'} | TED Residency | Why are transgender people suddenly everywhere? (Laughter) As a trans activist, I get this question a lot. Keep in mind, less than one percent of American adults openly identify as trans. According to a recent GLAAD survey, about 16 percent of non-trans Americans claim to know a trans person in real life. So for the other 84 percent, this may seem like a new topic. But trans people are not new. Gender variance is older than you think, and trans people are part of that legacy. From central Africa to South America to the Pacific Islands and beyond, there have been populations who recognize multiple genders, and they go way back. The hijra of India and Pakistan, for example, have been cited as far back as 2,000 years ago in the Kama Sutra. Indigenous American nations each have their own terms, but most share the umbrella term "two-spirit." They saw gender-variant people as shamans and healers in their communities, and it wasn't until the spread of colonialism that they were taught to think otherwise. Now, in researching trans history, we look for both trans people and trans practices. Take, for example, the women who presented as men so they could fight in the US Civil War. After the war, most resumed their lives as women, but some, like Albert Cashier, continued to live as men. Albert was eventually confined to an asylum and forced to wear a dress for the rest of his life. (Sighs) Around 1895, a group of self-described androgynes formed the Cercle Hermaphroditos. Their mission was to unite for defense against the world's bitter persecution. And in doing that, they became one of the earliest trans support groups. By the '40s and '50s, medical researchers were starting to study trans medicine, but they were aided by their trans patients, like Louise Lawrence, a trans woman who had corresponded extensively with people who had been arrested for public cross-dressing. She introduced sexual researchers like Alfred Kinsey to a massive trans network. Other early figures would follow, like Virginia Prince, Reed Erickson and the famous Christine Jorgensen, who made headlines with her very public transition in 1952. But while white trans suburbanites were forming their own support networks, many trans people of color had to carve their own path. Some, like Miss Major Griffin-Gracy, walked in drag balls. Others were the so-called "street queens," who were often targeted by police for their gender expression and found themselves on the forefront of seminal events in the LGBT rights movement. This brings us to the riots at Cooper Do-nuts in 1959, Compton's Cafeteria in 1966 and the famous Stonewall Inn in 1969. In 1970, Sylvia Rivera and Marsha P. Johnson, two veterans of Stonewall, established STAR: Street Transvestite Action Revolutionaries. Trans people continued to fight for equal treatment under the law, even as they faced higher rates of discrimination, unemployment, arrests, and the looming AIDS epidemic. For as long as we've been around, those in power have sought to disenfranchise trans people for daring to live lives that are ours. This motion picture still, taken in Berlin in 1933, is sometimes used in history textbooks to illustrate how the Nazis burned works they considered un-German. But what's rarely mentioned is that included in this massive pile are works from the Institute for Sexual Research. See, I just recapped the trans movement in America, but Magnus Hirschfeld and his peers in Germany had us beat by a few decades. Magnus Hirschfeld was an early advocate for LGBT people. He wrote the first book-length account of trans individuals. He helped them obtain medical services and IDs. He worked with the Berlin Police Department to end discrimination of LGBT people, and he hired them at the Institute. So when the Nazi Party burned his library, it had devastating implications for trans research around the world. This was a deliberate attempt to erase trans people, and it was neither the first nor the last. So whenever people ask me why trans people are suddenly everywhere, I just want to tell them that we've been here. These stories have to be told, along with the countless others that have been buried by time. Not only were our lives not celebrated, but our struggles have been forgotten and, yeah, to some people, that makes trans issues seem new. Today, I meet a lot of people who think that our movement is just a phase that will pass, but I also hear well-intentioned allies telling us all to be patient, because our movement is "still new." Imagine how the conversation would shift if we acknowledge just how long trans people have been demanding equality. Are we still overreacting? Should we continue to wait? Or should we, for example, do something about the trans women of color who are murdered and whose killers never see justice? Do our circumstances seem dire to you yet? (Sighs) Finally, I want other trans people to realize they're not alone. I grew up thinking my identity was an anomaly that would die with me. People drilled this idea of otherness into my mind, and I bought it because I didn't know anyone else like me. Maybe if I had known my ancestors sooner, it wouldn't have taken me so long to find a source of pride in my identity and in my community. Because I belong to an amazing, vibrant community of people that uplift each other even when others won't, that take care of each other even when we are struggling, that somehow, despite it all, still find cause to celebrate each other, to love each other, to look one another in the eyes and say, "You are not alone. You have us. And we're not going anywhere." Thank you. (Applause) |
Frida Kahlo: The woman behind the legend | null | TED-Ed | In 1925, Frida Kahlo was on her way home from school in Mexico City when the bus she was riding collided with a streetcar. She suffered near-fatal injuries to her spine, pelvis and hips, and was bedridden for months afterward. During her recovery, she had a special easel attached to her bed so she could practice painting techniques. When she set to work, she began to paint the world according to her own singular vision. Over the course of her life, she would establish herself as the creator and muse behind extraordinary art. Though you may have met Kahlo's gaze before, her work provides an opportunity to see the world through her eyes. She painted friends and family, still lives and spiritual scenes; but it was her mesmerizing self-portraits which first caught the world’s attention. In an early work, "Self Portrait with Velvet Dress," the focus is on her strong brows, facial hair, long neck and formidable stare. Such features remained, but Kahlo soon began to present herself in more unusual ways. For example, "The Broken Column" uses symbolism, religious imagery and a ruptured landscape to reveal her physical and mental state. In 1928, Kahlo started dating fellow painter Diego Rivera. They became lifelong partners and cultivated an eccentric celebrity. Together, they traveled the world and dedicated themselves to art, Communist politics and Mexican nationalism. Kahlo and Rivera shared a deep affinity with Mexicanidad, a movement which celebrated indigenous culture after the Revolution. In her daily life, Kahlo wore traditional Tehuana dress and immersed herself in native spirituality. And in her work, she constantly referenced Mexican folk painting, incorporating its bright colors and references to death, religion and nature. With her imagery of giant floating flowers, undulating landscapes, transplanted body parts and billowing clouds of demons, Kahlo has often been associated with Surrealism. But while surrealists used dreamlike images to explore the unconscious mind, Kahlo used them to represent her physical body and life experiences. Two of her most-explored experiences were her physical disabilities and her marriage. As a result of the bus accident, she experienced life-long health complications and endured many hospitalizations. She often contemplated the physical and psychological effects of disability in her work; painting herself in agony, recuperating from operations, or including objects such as her back brace and wheelchair. Meanwhile, her relationship with Rivera was tempestuous, marked by infidelity on both sides. At one point they even divorced, then remarried a year later. During this period, she painted the double self-portrait "The Two Fridas," which speaks to the anguish of loss and a splintered sense of self. The Frida to the left has a broken heart, which drips blood onto her old-fashioned Victorian dress. She symbolizes a version of the artist who is wounded by the past– but is also connected by an artery to a second self. This Frida is dressed in Tehuana attire– and although she remembers Diego with the tiny portrait in her hand, her heart remains intact. Together, the two suggest a position caught between past and present, individuality and dependency. Kahlo died in 1954 at the age of 47. In the years after her death, she experienced a surge in popularity that has lasted to this day. And although her image has proliferated, Kahlo’s body of work reminds us that there are no simple truths about the life, work and legacy of the woman behind the icon. Rather, she put multiple versions of her reality on display– and provided us with a few entry-ways into the contents of her soul. |
"East Virginia" / "John Brown's Dream" | {0: 'Nora Brown sings ballads and plays traditional old-time music with a heavy interest in eastern Kentucky banjo playing. '} | TED Salon: Education Everywhere | (Music: "East Virginia") (Banjo) (Singing) I'm from old East Virginia. North Carolina I did go. I met a fair, young maiden. Her name I did not know. (Banjo) Don't that road look rough and rocky? Don't that sea look wide and deep? Don't my darlin' look the sweetest ... When she's in my arms asleep? (Banjo) Her hair was a dark-brown curly. Her cheeks were chestnut red. On her breast she wore a white lilly. Through the night, the tears she shed. (Banjo) Captain, Captain, I am dyin'. Won't you take these words for me? Take them back to old East Virginia. Tell my darlin' she is free. (Banjo) (Music ends) (Applause and cheers) That was a song called "East Virginia" I learned from a man named Clifton Hicks who lives down in Georgia. The next song ... I have for you is called "John Brown's Dream." It's an old dance tune. And you may notice that the banjo that I'm holding looks a little different than banjos you might be used to seeing or the one I just played, for example. And this banjo is sort of an earlier model. Banjos kind of evolved like a human has. And I like to say that the sound that comes out of this banjo is a sound that was just a little closer to the source, which is Africa, and some people forget that, so, yeah ... (Banjo tuning) (Music: "John Brown's Dream") (Banjo) (Banjo continues) (Singing) John Brown's dream, John Brown's dream the devil was dead. I'm gonna get that, get that, get that, I'm gonna get that pretty little girl. (Banjo) John Brown's dream, John Brown's dream the devil was dead. (Banjo) Come on, Liza, Liza, Liza. Come on, Liza we'll be pickin' it again. I'm gonna get that, get that, get that, I'm gonna get that pretty little girl. (Banjo) (Music ends) (Applause and cheers) Thank you very much. |
Can we regenerate heart muscle with stem cells? | {0: 'Chuck Murry founded and currently directs the Institute for Stem Cell and Regenerative Medicine at the University of Washington.'} | TEDxSeattle | I'd like to tell you about a patient named Donna. In this photograph, Donna was in her mid-70s, a vigorous, healthy woman, the matriarch of a large clan. She had a family history of heart disease, however, and one day, she had the sudden onset of crushing chest pain. Now unfortunately, rather than seeking medical attention, Donna took to her bed for about 12 hours until the pain passed. The next time she went to see her physician, he performed an electrocardiogram, and this showed that she'd had a large heart attack, or a "myocardial infarction" in medical parlance. After this heart attack, Donna was never quite the same. Her energy levels progressively waned, she couldn't do a lot of the physical activities she'd previously enjoyed. It got to the point where she couldn't keep up with her grandkids, and it was even too much work to go out to the end of the driveway to pick up the mail. One day, her granddaughter came by to walk the dog, and she found her grandmother dead in the chair. Doctors said it was a cardiac arrhythmia that was secondary to heart failure. But the last thing that I should tell you is that Donna was not just an ordinary patient. Donna was my mother. Stories like ours are, unfortunately, far too common. Heart disease is the number one killer in the entire world. In the United States, it's the most common reason patients are admitted to the hospital, and it's our number one health care expense. We spend over a 100 billion dollars — billion with a "B" — in this country every year on the treatment of heart disease. Just for reference, that's more than twice the annual budget of the state of Washington. What makes this disease so deadly? Well, it all starts with the fact that the heart is the least regenerative organ in the human body. Now, a heart attack happens when a blood clot forms in a coronary artery that feeds blood to the wall of the heart. This plugs the blood flow, and the heart muscle is very metabolically active, and so it dies very quickly, within just a few hours of having its blood flow interrupted. Since the heart can't grow back new muscle, it heals by scar formation. This leaves the patient with a deficit in the amount of heart muscle that they have. And in too many people, their illness progresses to the point where the heart can no longer keep up with the body's demand for blood flow. This imbalance between supply and demand is the crux of heart failure. So when I talk to people about this problem, I often get a shrug and a statement to the effect of, "Well, you know, Chuck, we've got to die of something." (Laughter) And yeah, but what this also tells me is that we've resigned ourselves to this as the status quo because we have to. Or do we? I think there's a better way, and this better way involves the use of stem cells as medicines. So what, exactly, are stem cells? If you look at them under the microscope, there's not much going on. They're just simple little round cells. But that belies two remarkable attributes. The first is they can divide like crazy. So I can take a single cell, and in a month's time, I can grow this up to billions of cells. The second is they can differentiate or become more specialized, so these simple little round cells can turn into skin, can turn into brain, can turn into kidney and so forth. Now, some tissues in our bodies are chock-full of stem cells. Our bone marrow, for example, cranks out billions of blood cells every day. Other tissues like the heart are quite stable, and as far as we can tell, the heart lacks stem cells entirely. So for the heart, we're going to have to bring stem cells in from the outside, and for this, we turn to the most potent stem cell type, the pluripotent stem cell. Pluripotent stem cells are so named because they can turn into any of the 240-some cell types that make up the human body. So this is my big idea: I want to take human pluripotent stem cells, grow them up in large numbers, differentiate them into cardiac muscle cells and then take them out of the dish and transplant them into the hearts of patients who have had heart attacks. I think this is going to reseed the wall with new muscle tissue, and this will restore contractile function to the heart. (Applause) Now, before you applaud too much, this was my idea 20 years ago. (Laughter) And I was young, I was full of it, and I thought, five years in the lab, and we'll crank this out, and we'll have this into the clinic. Let me tell you what really happened. (Laughter) We began with the quest to turn these pluripotent stem cells into heart muscle. And our first experiments worked, sort of. We got these little clumps of beating human heart muscle in the dish, and that was cool, because it said, in principle, this should be able to be done. But when we got around to doing the cell counts, we found that only one out of 1,000 of our stem cells were actually turning into heart muscle. The rest was just a gemisch of brain and skin and cartilage and intestine. So how do you coax a cell that can become anything into becoming just a heart muscle cell? Well, for this we turned to the world of embryology. For over a century, the embryologists had been pondering the mysteries of heart development. And they had given us what was essentially a Google Map for how to go from a single fertilized egg all the way over to a human cardiovascular system. So we shamelessly absconded all of this information and tried to make human cardiovascular development happen in a dish. It took us about five years, but nowadays, we can get 90 percent of our stem cells to turn into cardiac muscle — a 900-fold improvement. So this was quite exciting. This slide shows you our current cellular product. We grow our heart muscle cells in little three-dimensional clumps called cardiac organoids. Each of them has 500 to 1,000 heart muscle cells in it. If you look closely, you can see these little organoids are actually twitching; each one is beating independently. But they've got another trick up their sleeve. We took a gene from jellyfish that live in the Pacific Northwest, and we used a technique called genome editing to splice this gene into the stem cells. And this makes our heart muscle cells flash green every time they beat. OK, so now we were finally ready to begin animal experiments. We took our cardiac muscle cells and we transplanted them into the hearts of rats that had been given experimental heart attacks. A month later, I peered anxiously down through my microscope to see what we had grown, and I saw ... nothing. Everything had died. But we persevered on this, and we came up with a biochemical cocktail that we called our "pro-survival cocktail," and this was enough to allow our cells to survive through the stressful process of transplantation. And now when I looked through the microscope, I could see this fresh, young, human heart muscle growing back in the injured wall of this rat's heart. So this was getting quite exciting. The next question was: Will this new muscle beat in synchrony with the rest of the heart? So to answer that, we returned to the cells that had that jellyfish gene in them. We used these cells essentially like a space probe that we could launch into a foreign environment and then have that flashing report back to us about their biological activity. What you're seeing here is a zoomed-in view, a black-and-white image of a guinea pig's heart that was injured and then received three grafts of our human cardiac muscle. So you see those sort of diagonally running white lines. Each of those is a needle track that contains a couple of million human cardiac muscle cells in it. And when I start the video, you can see what we saw when we looked through the microscope. Our cells are flashing, and they're flashing in synchrony, back through the walls of the injured heart. What does this mean? It means the cells are alive, they're well, they're beating, and they've managed to connect with one another so that they're beating in synchrony. But it gets even more interesting than this. If you look at that tracing that's along the bottom, that's the electrocardiogram from the guinea pig's own heart. And if you line up the flashing with the heartbeat that's shown on the bottom, what you can see is there's a perfect one-to-one correspondence. In other words, the guinea pig's natural pacemaker is calling the shots, and the human heart muscle cells are following in lockstep like good soldiers. (Applause) Our current studies have moved into what I think is going to be the best possible predictor of a human patient, and that's into macaque monkeys. This next slide shows you a microscopic image from the heart of a macaque that was given an experimental heart attack and then treated with a saline injection. This is essentially like a placebo treatment to show the natural history of the disease. The macaque heart muscle is shown in red, and in blue, you see the scar tissue that results from the heart attack. So as you look as this, you can see how there's a big deficiency in the muscle in part of the wall of the heart. And it's not hard to imagine how this heart would have a tough time generating much force. Now in contrast, this is one of the stem-cell-treated hearts. Again, you can see the monkey's heart muscle in red, but it's very hard to even see the blue scar tissue, and that's because we've been able to repopulate it with the human heart muscle, and so we've got this nice, plump wall. OK, let's just take a second and recap. I've showed you that we can take our stem cells and differentiate them into cardiac muscle. We've learned how to keep them alive after transplantation, we've showed that they beat in synchrony with the rest of the heart, and we've shown that we can scale them up into an animal that is the best possible predictor of a human's response. You'd think that we hit all the roadblocks that lay in our path, right? Turns out, not. These macaque studies also taught us that our human heart muscle cells created a period of electrical instability. They caused ventricular arrhythmias, or irregular heartbeats, for several weeks after we transplanted them. This was quite unexpected, because we hadn't seen this in smaller animals. We've studied it extensively, and it turns out that it results from the fact that our cellular graphs are quite immature, and immature heart muscle cells all act like pacemakers. So what happens is, we put them into the heart, and there starts to be a competition with the heart's natural pacemaker over who gets to call the shots. It would be sort of like if you brought a whole gaggle of teenagers into your orderly household all at once, and they don't want to follow the rules and the rhythms of the way you run things, and it takes a while to rein everybody in and get people working in a coordinated fashion. So our plans at the moment are to make the cells go through this troubled adolescence period while they're still in the dish, and then we'll transplant them in in the post-adolescent phase, where they should be much more orderly and be ready to listen to their marching orders. In the meantime, it turns out we can actually do quite well by treating with anti-arrhythmia drugs as well. So one big question still remains, and that is, of course, the whole purpose that we set out to do this: Can we actually restore function to the injured heart? To answer this question, we went to something that's called "left ventricular ejection fraction." Ejection fraction is simply the amount of blood that is squeezed out of the chamber of the heart with each beat. Now, in healthy macaques, like in healthy people, ejection fractions are about 65 percent. After a heart attack, ejection fraction drops down to about 40 percent, so these animals are well on their way to heart failure. In the animals that receive a placebo injection, when we scan them a month later, we see that ejection fraction is unchanged, because the heart, of course, doesn't spontaneously recover. But in every one of the animals that received a graft of human cardiac muscle cells, we see a substantial improvement in cardiac function. This averaged eight points, so from 40 to 48 percent. What I can tell you is that eight points is better than anything that's on the market right now for treating patients with heart attacks. It's better than everything we have put together. So if we could do eight points in the clinic, I think this would be a big deal that would make a large impact on human health. But it gets more exciting. That was just four weeks after transplantation. If we extend these studies out to three months, we get a full 22-point gain in ejection fraction. (Applause) Function in these treated hearts is so good that if we didn't know up front that these animals had had a heart attack, we would never be able to tell from their functional studies. Going forward, our plan is to start phase one, first in human trials here at the University of Washington in 2020 — two short years from now. Presuming these studies are safe and effective, which I think they're going to be, our plan is to scale this up and ship these cells all around the world for the treatment of patients with heart disease. Given the global burden of this illness, I could easily imagine this treating a million or more patients a year. So I envision a time, maybe a decade from now, where a patient like my mother will have actual treatments that can address the root cause and not just manage her symptoms. This all comes from the fact that stem cells give us the ability to repair the human body from its component parts. In the not-too-distant future, repairing humans is going to go from something that is far-fetched science fiction into common medical practice. And when this happens, it's going to have a transformational effect that rivals the development of vaccinations and antibiotics. Thank you for your attention. (Applause) |
How centuries of sci-fi sparked spaceflight | {0: 'TED Senior Fellow Alexander MacDonald develops strategies to advance space exploration and encourage private-sector space activities.'} | TEDxAuckland | I want to tell you a story about stories. And I want to tell you this story because I think we need to remember that sometimes the stories we tell each other are more than just tales or entertainment or narratives. They're also vehicles for sowing inspiration and ideas across our societies and across time. The story I'm about to tell you is about how one of the most advanced technological achievements of the modern era has its roots in stories, and how some of the most important transformations yet to come might also. The story begins over 300 years ago, when Galileo Galilei first learned of the recent Dutch invention that took two pieces of shaped glass and put them in a long tube and thereby extended human sight farther than ever before. When Galileo turned his new telescope to the heavens and to the Moon in particular, he discovered something incredible. These are pages from Galileo's book "Sidereus Nuncius," published in 1610. And in them, he revealed to the world what he had discovered. And what he discovered was that the Moon was not just a celestial object wandering across the night sky, but rather, it was a world, a world with high, sunlit mountains and dark "mare," the Latin word for seas. And once this new world and the Moon had been discovered, people immediately began to think about how to travel there. And just as importantly, they began to write stories about how that might happen and what those voyages might be like. One of the first people to do so was actually the Bishop of Hereford, a man named Francis Godwin. Godwin wrote a story about a Spanish explorer, Domingo Gonsales, who ended up marooned on the island of St. Helena in the middle of the Atlantic, and there, in an effort to get home, developed a machine, an invention, to harness the power of the local wild geese to allow him to fly — and eventually to embark on a voyage to the Moon. Godwin's book, "The Man in the Moone, or a Discourse of a Voyage Thither," was only published posthumously and anonymously in 1638, likely on account of the number of controversial ideas that it contained, including an endorsement of the Copernican view of the universe that put the Sun at the center of the Solar System, as well as a pre-Newtonian concept of gravity that had the idea that the weight of an object would decrease with increasing distance from Earth. And that's to say nothing of his idea of a goose machine that could go to the Moon. (Laughter) And while this idea of a voyage to the Moon by goose machine might not seem particularly insightful or technically creative to us today, what's important is that Godwin described getting to the Moon not by a dream or by magic, as Johannes Kepler had written about, but rather, through human invention. And it was this idea that we could build machines that could travel into the heavens, that would plant its seed in minds across the generations. The idea was next taken up by his contemporary, John Wilkins, then just a young student at Oxford, but later, one of the founders of the Royal Society. John Wilkins took the idea of space travel in Godwin's text seriously and wrote not just another story but a nonfiction philosophical treatise, entitled, "Discovery of the New World in the Moon, or, a Discourse Tending to Prove that 'tis Probable There May Be Another Habitable World in that Planet." And note, by the way, that word "habitable." That idea in itself would have been a powerful incentive for people thinking about how to build machines that could go there. In his books, Wilkins seriously considered a number of technical methods for spaceflight, and it remains to this day the earliest known nonfiction account of how we might travel to the Moon. Other stories would soon follow, most notably by Cyrano de Bergerac, with his "Lunar Tales." By the mid-17th century, the idea of people building machines that could travel to the heavens was growing in complexity and technical nuance. And yet, in the late 17th century, this intellectual progress effectively ceased. People still told stories about getting to the Moon, but they relied on the old ideas or, once again, on dreams or on magic. Why? Well, because the discovery of the laws of gravity by Newton and the invention of the vacuum pump by Robert Hooke and Robert Boyle meant that people now understood that a condition of vacuum existed between the planets, and consequentially between the Earth and the Moon. And they had no way of overcoming this, no way of thinking about overcoming this. And so, for well over a century, the idea of a voyage to the Moon made very little intellectual progress until the rise of the Industrial Revolution and the development of steam engines and boilers and most importantly, pressure vessels. And these gave people the tools to think about how they could build a capsule that could resist the vacuum of space. So it was in this context, in 1835, that the next great story of spaceflight was written, by Edgar Allan Poe. Now, today we think of Poe in terms of gothic poems and telltale hearts and ravens. But he considered himself a technical thinker. He grew up in Baltimore, the first American city with gas street lighting, and he was fascinated by the technological revolution that he saw going on all around him. He considered his own greatest work not to be one of his gothic tales but rather his epic prose poem "Eureka," in which he expounded his own personal view of the cosmographical nature of the universe. In his stories, he would describe in fantastical technical detail machines and contraptions, and nowhere was he more influential in this than in his short story, "The Unparalleled Adventure of One Hans Pfaall." It's a story of an unemployed bellows maker in Rotterdam, who, depressed and tired of life — this is Poe, after all — and deeply in debt, he decides to build a hermetically enclosed balloon-borne carriage that is launched into the air by dynamite and from there, floats through the vacuum of space all the way to the lunar surface. And importantly, he did not develop this story alone, for in the appendix to his tale, he explicitly acknowledged Godwin's "A Man in the Moone" from over 200 years earlier as an influence, calling it "a singular and somewhat ingenious little book." And although this idea of a balloon-borne voyage to the Moon may seem not much more technically sophisticated than the goose machine, in fact, Poe was sufficiently detailed in the description of the construction of the device and in terms of the orbital dynamics of the voyage that it could be diagrammed in the very first spaceflight encyclopedia as a mission in the 1920s. And it was this attention to detail, or to "verisimilitude," as he called it, that would influence the next great story: Jules Verne's "From the Earth to the Moon," written in 1865. And it's a story that has a remarkable legacy and a remarkable similarity to the real voyages to the Moon that would take place over a hundred years later. Because in the story, the first voyage to the Moon takes place from Florida, with three people on board, in a trip that takes three days — exactly the parameters that would prevail during the Apollo program itself. And in an explicit tribute to Poe's influence on him, Verne situated the group responsible for this feat in the book in Baltimore, at the Baltimore Gun Club, with its members shouting, "Cheers for Edgar Poe!" as they began to lay out their plans for their conquest of the Moon. And just as Verne was influenced by Poe, so, too, would Verne's own story go on to influence and inspire the first generation of rocket scientists. The two great pioneers of liquid fuel rocketry in Russia and in Germany, Konstantin Tsiolkovsky and Hermann Oberth, both traced their own commitment to the field of spaceflight to their reading "From the Earth to the Moon" as teenagers, and then subsequently committing themselves to trying to make that story a reality. And Verne's story was not the only one in the 19th century with a long arm of influence. On the other side of the Atlantic, H.G. Wells's "War of the Worlds" directly inspired a young man in Massachusetts, Robert Goddard. And it was after reading "War of the Worlds" that Goddard wrote in his diary, one day in the late 1890s, of resting while trimming a cherry tree on his family's farm and having a vision of a spacecraft taking off from the valley below and ascending into the heavens. And he decided then and there that he would commit the rest of his life to the development of the spacecraft that he saw in his mind's eye. And he did exactly that. Throughout his career, he would celebrate that day as his anniversary day, his cherry tree day, and he would regularly read and reread the works of Verne and of Wells in order to renew his inspiration and his commitment over the decades of labor and effort that would be required to realize the first part of his dream: the flight of a liquid fuel rocket, which he finally achieved in 1926. So it was while reading "From the Earth to the Moon" and "The War of the Worlds" that the first pioneers of astronautics were inspired to dedicate their lives to solving the problems of spaceflight. And it was their treatises and their works in turn that inspired the first technical communities and the first projects of spaceflight, thus creating a direct chain of influence that goes from Godwin to Poe to Verne to the Apollo program and to the present-day communities of spaceflight. So why I have told you all this? Is it just because I think it's cool, or because I'm just weirdly fascinated by stories of 17th- and 19th-century science fiction? It is, admittedly, partly that. But I also think that these stories remind us of the cultural processes driving spaceflight and even technological innovation more broadly. As an economist working at NASA, I spend time thinking about the economic origins of our movement out into the cosmos. And when you look before the investments of billionaire tech entrepreneurs and before the Cold War Space Race, and even before the military investments in liquid fuel rocketry, the economic origins of spaceflight are found in stories and in ideas. It was in these stories that the first concepts for spaceflight were articulated. And it was through these stories that the narrative of a future for humanity in space began to propagate from mind to mind, eventually creating an intergenerational intellectual community that would iterate on the ideas for spacecraft until such a time as they could finally be built. This process has now been going on for over 300 years, and the result is a culture of spaceflight. It's a culture that involves thousands of people over hundreds of years. Because for hundreds of years, some of us have looked at the stars and longed to go. And because for hundreds of years, some of us have dedicated our labors to the development of the concepts and systems required to make those voyages possible. I also wanted to tell you about Godwin, Poe and Verne because I think their stories also tell us of the importance of the stories that we tell each other about the future more generally. Because these stories don't just transmit information or ideas. They can also nurture passions, passions that can lead us to dedicate our lives to the realization of important projects. Which means that these stories can and do influence social and technological forces centuries into the future. I think we need to realize this and remember it when we tell our stories. We need to work hard to write stories that don't just show us the possible dystopian paths we may take for a fear that the more dystopian stories we tell each other, the more we plant seeds for possible dystopian futures. Instead we need to tell stories that plant the seeds, if not necessarily for utopias, then at least for great new projects of technological, societal and institutional transformation. And if we think of this idea that the stories we tell each other can transform the future is fanciful or impossible, then I think we need to remember the example of this, our voyage to the Moon, an idea from the 17th century that propagated culturally for over 300 years until it could finally be realized. So, we need to write new stories, stories that, 300 years in the future, people will be able to look back upon and remark how they inspired us to new heights and to new shores, how they showed us new paths and new possibilities, and how they shaped our world for the better. Thank you. (Applause) |
"First Kiss" | null | TED-Ed | First Kiss Her mouth fell into my mouth like a summer snow, like a 5th season, like a fresh Eden, like Eden when Eve made God whimper with the liquid tilt of her hips— her kiss hurt like that— I mean, it was as if she’d mixed the sweat of an angel with the taste of a tangerine, I swear. My mouth had been a helmet forever greased with secrets, my mouth a dead-end street a little bit lit by teeth—my heart, a clam slammed shut at the bottom of a dark, but her mouth pulled up like a baby-blue Cadillac packed with canaries driven by a toucan—I swear those lips said bright wings when we kissed, wild and precise—as if she were teaching a seahorse to speak— her mouth so careful, chumming the first vowel from my throat until my brain was a piano banged loud, hammered like that— it was like, I swear her tongue was Saturn’s 7th moon— hot like that, hot and cold and circling, circling, turning me into a glad planet— sun on one side, night pouring her slow hand over the other: one fire flying the kite of another. Her kiss, I swear—if the Great Mother rushed open the moon like a gift and you were there to feel your shadow finally unhooked from your wrist. That’d be it, but even sweeter— like a riot of peg-legged priests on pogo-sticks, up and up, this way and this, not falling but on and on like that, badly behaved but holy—I swear! That kiss: both lips utterly committed to the world like a Peace Corps, like a free store, forever and always a new city—no locks, no walls, just doors—like that, I swear, like that. |
Who were the Vestal Virgins, and what was their job? | null | TED-Ed | A lone priestess walks towards an underground chamber. People line the streets to watch as she proclaims her innocence. It doesn't matter. She's already been judged and found guilty. The sentence? Live burial. The underground chamber contains a portion of bread, water, milk, and oil. She will have a lamp, a bed, and a blanket, but she won't emerge alive. At the threshold, the priestess pauses, claims her innocence one last time, then enters the chamber never to be seen again by the Roman people. The priestess is one of Rome's six Vestal Virgins, each carefully selected as children from Rome's most aristocratic families. But now with her death, there are only five, and a new priestess must be chosen. The six-year-old Licinia witnessed the spectacle, never suspecting that a few days later, she'd be chosen as the next Vestal Virgin. Her age, her patrician family lineage, and her apparent good health makes her the best candidate to serve the goddess Vesta in the eyes of the Romans. Her parents are proud that their daughter's been chosen. Licinia is afraid, but she has no choice in the matter. She must serve the goddess for at least the next 30 years. For the first ten years of Licinia's service, she's considered in training, learning how to be a Vestal Virgin. Her most important duty is keeping vigil over the flame of Vesta, the virgin goddess of the hearth. Vesta doesn't have a statue like other Roman gods and goddesses. Instead, she's represented by the flame which burns day and night in her temple located next to the Forum in the center of the city. Like all Vestal priestesses, Licinia spends part of each day on shift, watching and tending to the flame. The flame represents two things. The first is the continuation of Rome as a power in the world. The Romans believed that if the flame goes out, the city's in danger. The flame also symbolizes the continuing virginity of Vesta's priestesses. For the Romans, a Vestal's virginity signaled not only her castitas, or modest spirit and body, but also her ritual purity. So Licinia knows she must never let the flame go out. Her life, the lives of her fellow Vestals, and the safety of Rome itself depends upon it. Licinia learns to collect water each day from a nearby fountain to cleanse the temple. She learns the Fasti, the calendar of sacred rituals and she watches while the senior priestesses conduct sacrifices. By the time Licinia completes her training, she's 16 years old. Licinia understands that the way she must act is a reflection of the goddess she serves. When it's her turn to collect the water, she keeps her eyes lowered to the ground. When she performs sacrifices, she focuses intently on the task. Licinia directs her energy towards being the best priestess she can be. She's worried that someday the state will claim her life for its own purposes to protect itself from danger. Licinia could be accused of incestum, meaning unchastity, at any time and be sacrificed whether she's innocent or guilty. Licinia fully understands now why her predecessor was buried alive. Ten years ago, the flame of Vesta went out. The priestesses knew that they couldn't keep it a secret. The future of Rome depended upon it. They went to the chief priest and he opened an investigation to discover why the flame had failed. Someone came forward and claimed that one of the Vestals was no longer a virgin. That was the beginning of the end. The accused protested her innocence, but it wasn't enough. She was tried and found guilty. That Vestal's death was meant to protect the city, but Licinia weeps for what has been lost and for what she knows now. Her own path was paved by the death of another, and her life could be taken just as easily for something as simple as a flame going out. |
Is space trying to kill us? | null | TED-Ed | There are still lots of things about space that we may never be able to answer, like is time travel possible? Or are aliens living somewhere else in the Milky Way? But there is one thing I believe about space: Space is trying to kill me. Space isn't out to get me personally. It's also trying to kill you and everybody else. Think about it. Space doesn't naturally have what we need to survive when we travel there: no air, it's too hot or too cold, no ozone to protect us from those nasty UV rays, either. This all sounds bad, but what can space really do to me if I stay on Earth? What we need to understand is that objects in space can cause people to think their days are numbered, even when there are events on Earth that can hurt or kill us before something from space does. So, what are the odds that one of these objects will really affect Earth and you and me in our lifetime? Well, we can take what we know about the universe to try and figure that out. You might have heard stories about asteroids hitting the Earth. That would be pretty bad. Scientists think asteroids might have killed off most of the dinosaurs. Sounds like something we should worry about, right? Well, astronomers can now watch asteroids in space and see them coming using complex computer models to predict the deadly rock's path. For a while, the reported odds that asteroid Apophis would strike Earth in 2036 were once 1 in 625. But, after updating their data, astronomers now say the chances are extremely low. Okay, what about the sun? Hollywood movies like to pick on our sun by showing Earth destroyed by solar flares or the sun dying out, which would cause Earth to freeze. Astronomers predict our sun contains enough gas to make energy for another 3 to 5 billion years. So, in 3 to 5 billion years, if people still exist on Earth, they'll have to deal with that. But today, well, we're safe. Sometimes the sun does shoot flares at Earth, but the magnetic fields surrounding our planet blocks most of that radiation. The radiation that does get through creates things like the Aurora Borealis. Gigantic solar flares can mess with our satellites and electrical equipment, but the chances of it killing you are pretty slim. Okay, what about that supermassive black hole in the middle of our galaxy? What happens to Earth, and us, when it pulls us in? After all, it is supermassive. Nope, not going to happen. That's one big object that can't bother us. How can we be so sure? Our solar system is on the edge of the Milky Way while the nearest supermassive black hole is about 26,000 light years from Earth. That means we aren't on that black hole's menu. So, you still think space objects are trying to kill you even after what I've told you so far? I think I've even convinced myself that odds are really good that space and the objects up there won't kill me after all. But I'll probably keep looking up just to make sure nothing is headed my way. |
5 tips to improve your critical thinking | null | TED-Ed | Every day, a sea of decisions stretches before us. Some are small and unimportant, but others have a larger impact on our lives. For example, which politician should I vote for? Should I try the latest diet craze? Or will email make me a millionaire? We're bombarded with so many decisions that it's impossible to make a perfect choice every time. But there are many ways to improve our chances, and one particularly effective technique is critical thinking. This is a way of approaching a question that allows us to carefully deconstruct a situation, reveal its hidden issues, such as bias and manipulation, and make the best decision. If the critical part sounds negative that's because in a way it is. Rather than choosing an answer because it feels right, a person who uses critical thinking subjects all available options to scrutiny and skepticism. Using the tools at their disposal, they'll eliminate everything but the most useful and reliable information. There are many different ways of approaching critical thinking, but here's one five-step process that may help you solve any number of problems. One: formulate your question. In other words, know what you're looking for. This isn't always as straightforward as it sounds. For example, if you're deciding whether to try out the newest diet craze, your reasons for doing so may be obscured by other factors, like claims that you'll see results in just two weeks. But if you approach the situation with a clear view of what you're actually trying to accomplish by dieting, whether that's weight loss, better nutrition, or having more energy, that'll equip you to sift through this information critically, find what you're looking for, and decide whether the new fad really suits your needs. Two: gather your information. There's lots of it out there, so having a clear idea of your question will help you determine what's relevant. If you're trying to decide on a diet to improve your nutrition, you may ask an expert for their advice, or seek other people's testimonies. Information gathering helps you weigh different options, moving you closer to a decision that meets your goal. Three: apply the information, something you do by asking critical questions. Facing a decision, ask yourself, "What concepts are at work?" "What assumptions exist?" "Is my interpretation of the information logically sound?" For example, in an email that promises you millions, you should consider, "What is shaping my approach to this situation?" "Do I assume the sender is telling the truth?" "Based on the evidence, is it logical to assume I'll win any money?" Four: consider the implications. Imagine it's election time, and you've selected a political candidate based on their promise to make it cheaper for drivers to fill up on gas. At first glance, that seems great. But what about the long-term environmental effects? If gasoline use is less restricted by cost, this could also cause a huge surge in air pollution, an unintended consequence that's important to think about. Five: explore other points of view. Ask yourself why so many people are drawn to the policies of the opposing political candidate. Even if you disagree with everything that candidate says, exploring the full spectrum of viewpoints might explain why some policies that don't seem valid to you appeal to others. This will allow you to explore alternatives, evaluate your own choices, and ultimately help you make more informed decisions. This five-step process is just one tool, and it certainly won't eradicate difficult decisions from our lives. But it can help us increase the number of positive choices we make. Critical thinking can give us the tools to sift through a sea of information and find what we're looking for. And if enough of us use it, it has the power to make the world a more reasonable place. |
Dead stuff: The secret ingredient in our food chain | {0: 'TED Senior Fellow Eric Berlow studies ecology and networks, exposing the interconnectedness of our ecosystems with climate change, government, corporations and more. '} | TED-Ed | If someone called you scum, you'd probably be offended, but scientifically, they might not be far off. Have you ever thought about where your food comes from? You might say it comes from plants, animals, or even fungi, but you'd probably rather not think about the rotting organisms and poop that feed those plants, animals, and fungi. So really, you and most of the matter in your body are just two or three degrees of separation from things like pond scum. All species in an ecosystem, from the creatures in a coral reef to the fish in a lake to the lions on the savannah, are directly or indirectly nourished by dead stuff. Most of the organic matter in our bodies, if we trace it back far enough, comes from CO2 and water through photosynthesis. Plants use the energy from sunlight to transform carbon dioxide and water from the environment into glucose and oxygen. That glucose is then transformed into more complex organic molecules to form leaves, stems, roots, fruit, and so on. The energy stored in these organic molecules supports the food chains with which we're familiar. You've probably seen illustrations like this or this. These green food chains start with living plants at their base. But in real-life terrestrial ecosystems, less than 10% of plant matter is eaten while it's still alive. What about the other 90? Well, just look at the ground on an autumn day. Living plants shed dead body parts: fallen leaves, broken branches, and even underground roots. Many plants are lucky enough to go their whole lives without being eaten, eventually dying and leaving remains. All of these uneaten, undigested, and dead plant parts, that 90% of terrestrial plant matter? That becomes detritus, the base of what we call the brown food chain, which looks more like this. What happens to plants also happens to all other organisms up the food chain: some are eaten alive, but most are eaten only when they're dead and rotting. And all along this food chain, living things shed organic matter and expel digestive waste before dying and leaving their remains to decay. All that death sounds grim, right? But it's not. All detritus is ultimately consumed by microbes and other scavengers, so it actually forms the base of the brown food chain that supports many other organisms, including us. Scientists are learning that this detritus is an unexpectedly huge energy source, fueling most natural ecosystems. But the interactions within an ecosystem are even more complex than that. What a food chain really represents is a single pathway of energy flow. And within any ecosystem, many of these flows are linked together to form a rich network of interactions, or food web, with dead matter supporting that network at every step. The resulting food web is so connected that almost every species is no more than two degrees from detritus, even us humans. You probably don't eat rotting things, poop, or pond scum directly, but your food sources probably do. Many animals we eat either feed directly on detritus themselves, like pork, poultry, mushrooms, shellfish, or catfish and other bottom feeders, or they are fed animal by-products. So, if you're thinking nature is full of waste, you're right. But one organism's garbage is another's gold, and all that rotting dead stuff ultimately provides the energy that nourishes us and most of life on Earth, as it passes through the food web. Now that's some food for thought. |
Plato's best (and worst) ideas | null | TED-Ed | Few individuals have influenced the world and many of today's thinkers like Plato. One 20th century philosopher even went so far as to describe all of Western philosophy as a series of footnotes to Plato. He created the first Western university and was teacher to Ancient Greece's greatest minds, including Aristotle. But even one of the founders of philosophy wasn't perfect. Along with his great ideas, Plato had a few that haven't exactly stood the test of time. So here are brief rundowns of a few of his best and worst ideas. Plato argued that beyond our imperfect world was a perfect unchanging world of Forms. Forms are the ideal versions of the things and concepts we see around us. They serve as a sort of instruction manual to our own world. Floating around the world of Forms is the ideal tree, and the ideal YouTube channel, and even the ideal justice, or ideal love. Our own reality is comprised of imperfect copies of ideal Forms. Plato argued that philosophers should strive to contemplate and understand these perfect Forms so that they may better navigate our misleading reality. While it may seem silly, the disconnect between the world as it appears and the greater truth behind it is one of philosophy's most vexing problems. It's been the subject of thousands of pages by theologians, philosophers, and screenwriters alike. It raises questions like should we trust our senses to come to the truth or our own reason? For Plato, the answer is reason. It alone provides us with at least the potential to contemplate the Forms. But reason didn't always pan out for Plato himself. When he sought to situate humankind amongst the animals, he lumped us in with birds. "Featherless bipeds" was his official designation. Diogenes the Cynic, annoyed by this definition, stormed into Plato's class with a plucked chicken, announcing, "Behold. Plato's man." But back to a few good ideas. Plato is one of the earliest political theorists on record, and with Aristotle, is seen as one of the founders of political science. He reasoned that being a ruler was no different than any other craft, whether a potter or doctor, and that only those who had mastered the craft were fit to lead. Ruling was the craft of contemplating the Forms. In his Republic, Plato imagined a utopia where justice is the ultimate goal. Plato's ideal city seeks a harmonious balance between its individual parts and should be lead by a philosopher king. Millennia before his time, Plato also reasoned that women were equally able to rule in this model city. Unfortunately, Plato was inconsistent with women, elsewhere likening them to children. He also believed that a woman's womb was a live animal that could wander around in her body and cause illness. This bad idea, also espoused by other contemporaries of Plato, was sadly influential for hundreds of years in European medicine. Furthermore, he thought that society should be divided into three groups: producers, the military, and the rulers, and that a great noble lie should convince everyone to follow this structure. The noble lie he proposed was that we're all born with gold, silver, or a mixture of brass and iron in our souls, which determine our roles in life. Some thinkers have gone on to credit the idea of the noble lie as a prototype for 20th century propaganda, and the philosopher king as inspiration for the dictators that used them. Should a few bad ideas tarnish Plato's status as one of the greatest philosophers in history? No! Plato gave the leaders and thinkers who came after him a place to start. Through the centuries, we've had the chance to test those ideas through writing and experience, and have accepted some while rejecting others. We are continuing to refine, amend, and edit his ideas which have become foundations of the modern world. |
The brilliance of bioluminescence | null | TED-Ed | Imagine a place so dark you can't see the nose on your face. Eyes opened or closed, it's all the same because the sun never shines there. Up ahead, you see a light. When you creep in to investigate, a blue light flits around you. "I could watch this forever," you think. But you can't because the mouth of an anglerfish has just sprung open and eaten you alive. You are just one of many creatures at the bottom of the ocean who learn too late to appreciate the power of bioluminescence. Bioluminescence refers to the ability of certain living things to create light. The human body can make stuff like ear wax and toe nails, but these organisms can turn parts of their body into glow sticks. It's like nature made them ready to rave. Why? In one way or another, bioluminescence improves a living thing's chances of survival. Take the firefly. It's ability to glow green helps it attract a mate on a warm, summer night, but it's just one of many living things that can glow. The railroad worm, Phrixothrix hirtus, can light up its body in two colors: red and green. Would you eat something that looks like an airport runway? Neither would any sensible predator. The flashing lights keep the worm safe. Then there's the deep sea shrimp, Acantherphyra purpurea. When it feels threatened, it spews a cloud of glowing goo from its mouth. Who doesn't run the other way when they've just been puked on? Plus, that puke attracts bigger predators who want to eat the shrimp's enemy. So what if you can't bioluminesce? No problem! There are other ways for living things to make bioluminescence work for them, even if they weren't born with the equipment to glow. Let's revisit the anglerfish moments before it tried to eat you. That glowing bait on top of its head? It comes from a pocket of skin called the esca. The esca holds bioluminescent bacteria. The anglerfish can't glow there by itself, so it holds a sack of glowing bacteria instead. Remember the firefly? It can actually make itself glow. Inside its lantern are two chemicals, a luciferin and a luciferase. When firefly luciferase and luciferin mix together in the presence of oxygen and fuel for the cell, called ATP, the chemical reaction gives off energy in the form of light. Once scientists figured out how the firefly creates its luciferase and luciferin, they used genetic engineering to make this light-producing reaction occur inside other living things that can't glow. For example, they inserted the genes, or instructions, for a cell to create firefly luciferase and luciferin into a tobacco plant. Once there, the tobacco plant followed the instructions slipped into its DNA and lit up like a Christmas tree. The beauty of bioluminescence, unlike the light from the sun or an incandescent bulb, is that it's not hot. It takes place in a range of temperatures that don't burn a living thing. And unlike a glow stick, which fades out as the chemicals inside get used up, bioluminescent reactions use replenishable resources. That's one reason engineers are trying to develop bioluminescent trees. Just think, if planted on the side of highways, they could light the way, using only oxygen and other freely available, clean resources to run. Talk about survival advantage! That could help our planet live longer. Do you find yourself thinking of other ways to put bioluminescence to good use? That glow stick you swing at a rave may help you find a mate, but how else can bioluminescence improve your survival? If you start thinking in this way, you have seen the light. |
Mary's Room: A philosophical thought experiment | null | TED-Ed | Imagine a brilliant neuroscientist named Mary. Mary lives in a black and white room, she only reads black and white books, and her screens only display black and white. But even though she has never seen color, Mary is an expert in color vision and knows everything ever discovered about its physics and biology. She knows how different wavelengths of light stimulate three types of cone cells in the retina, and she knows how electrical signals travel down the optic nerve into the brain. There, they create patterns of neural activity that correspond to the millions of colors most humans can distinguish. Now imagine that one day, Mary's black and white screen malfunctions and an apple appears in color. For the first time, she can experience something that she's known about for years. Does she learn anything new? Is there anything about perceiving color that wasn't captured in all her knowledge? Philosopher Frank Jackson proposed this thought experiment, called Mary's room, in 1982. He argued that if Mary already knew all the physical facts about color vision, and experiencing color still teaches her something new, then mental states, like color perception, can't be completely described by physical facts. The Mary's room thought experiment describes what philosophers call the knowledge argument, that there are non-physical properties and knowledge which can only be discovered through conscious experience. The knowledge argument contradicts the theory of physicalism, which says that everything, including mental states, has a physical explanation. To most people hearing Mary's story, it seems intuitively obvious that actually seeing color will be totally different than learning about it. Therefore, there must be some quality of color vision that transcends its physical description. The knowledge argument isn't just about color vision. Mary's room uses color vision to represent conscious experience. If physical science can't entirely explain color vision, then maybe it can't entirely explain other conscious experiences either. For instance, we could know every physical detail about the structure and function of someone else's brain, but still not understand what it feels like to be that person. These ineffable experiences have properties called qualia, subjective qualities that you can't accurately describe or measure. Qualia are unique to the person experiencing them, like having an itch, being in love, or feeling bored. Physical facts can't completely explain mental states like this. Philosophers interested in artificial intelligence have used the knowledge argument to theorize that recreating a physical state won't necessarily recreate a corresponding mental state. In other words, building a computer which mimicked the function of every single neuron of the human brain won't necessarily create a conscious computerized brain. Not all philosophers agree that the Mary's room experiment is useful. Some argue that her extensive knowledge of color vision would have allowed her to create the same mental state produced by actually seeing the color. The screen malfunction wouldn't show her anything new. Others say that her knowledge was never complete in the first place because it was based only on those physical facts that can be conveyed in words. Years after he proposed it, Jackson actually reversed his own stance on his thought experiment. He decided that even Mary's experience of seeing red still does correspond to a measurable physical event in the brain, not unknowable qualia beyond physical explanation. But there still isn't a definitive answer to the question of whether Mary would learn anything new when she sees the apple. Could it be that there are fundamental limits to what we can know about something we can't experience? And would this mean there are certain aspects of the universe that lie permanently beyond our comprehension? Or will science and philosophy allow us to overcome our mind's limitations? |
Where does gold come from? | null | TED-Ed | In medieval times, alchemists tried to achieve the seemingly impossible. They wanted to transform lowly lead into gleaming gold. History portrays these people as aged eccentrics, but if only they'd known that their dreams were actually achievable. Indeed, today we can manufacture gold on Earth thanks to modern inventions that those medieval alchemists missed by a few centuries. But to understand how this precious metal became embedded in our planet to start with, we have to gaze upwards at the stars. Gold is extraterrestrial. Instead of arising from the planet's rocky crust, it was actually cooked up in space and is present on Earth because of cataclysmic stellar explosions called supernovae. Stars are mostly made up of hydrogen, the simplest and lightest element. The enormous gravitational pressure of so much material compresses and triggers nuclear fusion in the star's core. This process releases energy from the hydrogen, making the star shine. Over many millions of years, fusion transforms hydrogen into heavier elements: helium, carbon, and oxygen, burning subsequent elements faster and faster to reach iron and nickel. However, at that point nuclear fusion no longer releases enough energy, and the pressure from the core peters out. The outer layers collapse into the center, and bouncing back from this sudden injection of energy, the star explodes forming a supernova. The extreme pressure of a collapsing star is so high, that subatomic protons and electrons are forced together in the core, forming neutrons. Neutrons have no repelling electric charge so they're easily captured by the iron group elements. Multiple neutron captures enable the formation of heavier elements that a star under normal circumstances can't form, from silver to gold, past lead and on to uranium. In extreme contrast to the million year transformation of hydrogen to helium, the creation of the heaviest elements in a supernova takes place in only seconds. But what becomes of the gold after the explosion? The expanding supernova shockwave propels its elemental debris through the interstellar medium, triggering a swirling dance of gas and dust that condenses into new stars and planets. Earth's gold was likely delivered this way before being kneaded into veins by geothermal activity. Billions of years later, we now extract this precious product by mining it, an expensive process that's compounded by gold's rarity. In fact, all of the gold that we've mined in history could be piled into just three Olympic-size swimming pools, although this represents a lot of mass because gold is about 20 times denser than water. So, can we produce more of this coveted commodity? Actually, yes. Using particle accelerators, we can mimic the complex nuclear reactions that create gold in stars. But these machines can only construct gold atom by atom. So it would take almost the age of the universe to produce one gram at a cost vastly exceeding the current value of gold. So that's not a very good solution. But if we were to reach a hypothetical point where we'd mined all of the Earth's buried gold, there are other places we could look. The ocean holds an estimated 20 million tons of dissolved gold but at extremely miniscule concentrations making its recovery too costly at present. Perhaps one day, we'll see gold rushes to tap the mineral wealth of the other planets of our solar system. And who knows? Maybe some future supernova will occur close enough to shower us with its treasure and hopefully not eradicate all life on Earth in the process. |
What makes the Great Wall of China so extraordinary | null | TED-Ed | A 13,000 mile dragon of earth and stone winds its way through the countryside of China with a history almost as long and serpentine as the structure. The Great Wall began as multiple walls of rammed earth built by individual feudal states during the Chunqiu period to protect against nomadic raiders north of China and each other. When Emperor Qin Shi Huang unified the states in 221 BCE, the Tibetan Plateau and Pacific Ocean became natural barriers, but the mountains in the north remained vulnerable to Mongol, Turkish, and Xiongnu invasions. To defend against them, the Emperor expanded the small walls built by his predecessors, connecting some and fortifying others. As the structures grew from Lintao in the west to Liaodong in the east, they collectively became known as The Long Wall. To accomplish this task, the Emperor enlisted soldiers and commoners, not always voluntarily. Of the hundreds of thousands of builders recorded during the Qin Dynasty, many were forcibly conscripted peasants and others were criminals serving out sentences. Under the Han Dynasty, the wall grew longer still, reaching 3700 miles, and spanning from Dunhuang to the Bohai Sea. Forced labor continued under the Han Emperor Han-Wudi , and the walls reputation grew into a notorious place of suffering. Poems and legends of the time told of laborers buried in nearby mass graves, or even within the wall itself. And while no human remains have been found inside, grave pits do indicate that many workers died from accidents, hunger and exhaustion. The wall was formidable but not invincible. Both Genghis and his son Khublai Khan managed to surmount the wall during the Mongol invasion of the 13th Century. After the Ming dynasty gained control in 1368, they began to refortify and further consolidate the wall using bricks and stones from local kilns. Averaging 23 feet high and 21 feet wide, the walls 5500 miles were punctuated by watchtowers. When raiders were sighted, fire and smoke signals traveled between towers until reinforcements arrived. Small openings along the wall let archers fire on invaders, while larger ones were used to drop stones and more. But even this new and improved wall was not enough. In 1644, northern Manchu clans overthrew the Ming to establish the Qing dynasty, incorporating Mongolia as well, Thus, for the second time, China was ruled by the very people the wall had tried to keep out. With the empire's borders now extending beyond the Great Wall, the fortifications lost their purpose. And without regular reinforcement, the wall fell into disrepair, rammed earth eroded, while brick and stone were plundered for building materials. But its job wasn't finished. During World War II, China used sections for defense against Japanese invasion, and some parts are still rumored to be used for military training. But the Wall's main purpose today is cultural. As one of the largest man-made structures on Earth, it was granted UNESCO World Heritage Status in 1987. Originally built to keep people out of China, the Great Wall now welcomes millions of visitors each year. In fact, the influx of tourists has caused the wall to deteriorate, leading the Chinese government to launch preservation initiatives. It's also often acclaimed as the only man-made structure visible from space. Unfortunately, that's not at all true. In low Earth orbit, all sorts of structures, like bridges, highways and airports are visible, and the Great Wall is only barely discernible. From the moon, it doesn't stand a chance. But regardless, it's the Earth we should be studying it from because new sections are still discovered every few years, branching off from the main body and expanding this remarkable monument to human achievement. |
How to read music | null | TED-Ed | When we watch a film or a play, we know that the actors probably learned their lines from a script, which essentially tells them what to say and when to say it. A piece of written music operates on exactly the same principle. In a very basic sense, it tells a performer what to play and when to play it. Aesthetically speaking, there's a world of difference between, say, Beethoven and Justin Bieber, but both artists have used the same building blocks to create their music: notes. And although the end result can sound quite complicated, the logic behind musical notes is actually pretty straightforward. Let's take a look at the foundational elements to music notation and how they interact to create a work of art. Music is written on five parallel lines that go across the page. These five lines are called a staff, and a staff operates on two axes: up and down and left to right. The up-and-down axis tells the performer the pitch of the note or what note to play, and the left-to-right axis tells the performer the rhythm of the note or when to play it. Let's start with pitch. To help us out, we're going to use a piano, but this system works for pretty much any instrument you can think of. In the Western music tradition, pitches are named after the first seven letters of the alphabet, A, B, C, D, E, F, and G. After that, the cycle repeats itself: A, B, C, D, E, F, G, A, B, C, D, E, F, G, and so on. But how do these pitches get their names? Well, for example, if you played an F and then played another F higher or lower on the piano, you'd notice that they sound pretty similar compared to, say, a B. Going back to the staff, every line and every space between two lines represents a separate pitch. If we put a note on one of these lines or one of these spaces, we're telling a performer to play that pitch. The higher up on the staff a note is placed, the higher the pitch. But there are obviously many, many more pitches than the nine that these lines and spaces gives us. A grand piano, for example, can play 88 separate notes. So how do we condense 88 notes onto a single staff? We use something called a clef, a weird-looking figure placed at the beginning of the staff, which acts like a reference point, telling you that a particular line or space corresponds to a specific note on your instrument. If we want to play notes that aren't on the staff, we kind of cheat and draw extra little lines called ledger lines and place the notes on them. If we have to draw so many ledger lines that it gets confusing, then we need to change to a different clef. As for telling a performer when to play the notes, two main elements control this: the beat and the rhythm. The beat of a piece of music is, by itself, kind of boring. It sounds like this. (Ticking) Notice that it doesn't change, it just plugs along quite happily. It can go slow or fast or whatever you like, really. The point is that just like the second hand on a clock divides one minute into sixty seconds, with each second just as long as every other second, the beat divides a piece of music into little fragments of time that are all the same length: beats. With a steady beat as a foundation, we can add rhythm to our pitches, and that's when music really starts to happen. This is a quarter note. It's the most basic unit of rhythm, and it's worth one beat. This is a half note, and it's worth two beats. This whole note here is worth four beats, and these little guys are eighth notes, worth half a beat each. "Great," you say, "what does that mean?" You might have noticed that across the length of a staff, there are little lines dividing it into small sections. These are bar lines and we refer to each section as a bar. At the beginning of a piece of music, just after the clef, is something called the time signature, which tells a performer how many beats are in each bar. This says there are two beats in each bar, this says there are three, this one four, and so on. The bottom number tells us what kind of note is to be used as the basic unit for the beat. One corresponds to a whole note, two to a half note, four to a quarter note, and eight to an eighth note, and so on. So this time signature here tells us that there are four quarter notes in each bar, one, two, three, four; one, two, three, four, and so on. But like I said before, if we just stick to the beat, it gets kind of boring, so we'll replace some quarter notes with different rhythms. Notice that even though the number of notes in each bar has changed, the total number of beats in each bar hasn't. So, what does our musical creation sound like? (Music) Eh, sounds okay, but maybe a bit thin, right? Let's add another instrument with its own pitch and rhythm. Now it's sounding like music. Sure, it takes some practice to get used to reading it quickly and playing what we see on our instrument, but, with a bit of time and patience, you could be the next Beethoven or Justin Bieber. |
Schrödinger's cat: A thought experiment in quantum mechanics | {0: 'I’m an Associate Professor in the Department of Physics and Astronomy at Union College, and I write books about science for non-scientists. I also blog about physics and other things at Forbes.com and ScienceBlogs.com. I have a BA in physics from Williams College and a Ph.D. in Chemical Physics from the University of Maryland, College Park (studying laser cooling at the National Institute of Standards and Technology in the lab of Bill Phillips, who shared the 1997 Nobel in Physics). I was a post-doc at Yale, and have been at Union since 2001. My books _How to Teach Physics to Your Dog_ and _How to Teach Relativity to Your Dog_ explain modern physics through imaginary conversations with my German Shepherd, Emmy, and my most recent book, _Eureka: Discovering Your Inner Scientist_ (Basic, 2014), explains how we use the process of science in everyday activities. I live in Niskayuna, NY with my wife, Kate Nepveu, our two kids, and Emmy, the Queen of Niskayuna.'} | TED-Ed | Austrian physicist Erwin Schrödinger is one of the founders of quantum mechanics, but he's most famous for something he never actually did: a thought experiment involving a cat. He imagined taking a cat and placing it in a sealed box with a device that had a 50% chance of killing the cat in the next hour. At the end of that hour, he asked, "What is the state of the cat?" Common sense suggests that the cat is either alive or dead, but Schrödinger pointed out that according to quantum physics, at the instant before the box is opened, the cat is equal parts alive and dead, at the same time. It's only when the box is opened that we see a single definite state. Until then, the cat is a blur of probability, half one thing and half the other. This seems absurd, which was Schrödinger's point. He found quantum physics so philosophically disturbing, that he abandoned the theory he had helped make and turned to writing about biology. As absurd as it may seem, though, Schrödinger's cat is very real. In fact, it's essential. If it weren't possible for quantum objects to be in two states at once, the computer you're using to watch this couldn't exist. The quantum phenomenon of superposition is a consequence of the dual particle and wave nature of everything. In order for an object to have a wavelength, it must extend over some region of space, which means it occupies many positions at the same time. The wavelength of an object limited to a small region of space can't be perfectly defined, though. So it exists in many different wavelengths at the same time. We don't see these wave properties for everyday objects because the wavelength decreases as the momentum increases. And a cat is relatively big and heavy. If we took a single atom and blew it up to the size of the Solar System, the wavelength of a cat running from a physicist would be as small as an atom within that Solar System. That's far too small to detect, so we'll never see wave behavior from a cat. A tiny particle, like an electron, though, can show dramatic evidence of its dual nature. If we shoot electrons one at a time at a set of two narrow slits cut in a barrier, each electron on the far side is detected at a single place at a specific instant, like a particle. But if you repeat this experiment many times, keeping track of all the individual detections, you'll see them trace out a pattern that's characteristic of wave behavior: a set of stripes - regions with many electrons separated by regions where there are none at all. Block one of the slits and the stripes go away. This shows that the pattern is a result of each electron going through both slits at the same time. A single electron isn't choosing to go left or right but left and right simultaneously. This superposition of states also leads to modern technology. An electron near the nucleus of an atom exists in a spread out, wave-like orbit. Bring two atoms close together, and the electrons don't need to choose just one atom but are shared between them. This is how some chemical bonds form. An electron in a molecule isn't on just atom A or atom B, but A+ B. As you add more atoms, the electrons spread out more, shared between vast numbers of atoms at the same time. The electrons in a solid aren't bound to a particular atom but shared among all of them, extending over a large range of space. This gigantic superposition of states determines the ways electrons move through the material, whether it's a conductor or an insulator or a semiconductor. Understanding how electrons are shared among atoms allows us to precisely control the properties of semiconductor materials, like silicon. Combining different semiconductors in the right way allows us to make transistors on a tiny scale, millions on a single computer chip. Those chips and their spread out electrons power the computer you're using to watch this video. An old joke says that the Internet exists to allow the sharing of cat videos. At a very deep level, though, the Internet owes its existance to an Austrian physicist and his imaginary cat. |
3 tips to boost your confidence | null | TED-Ed | When faced with a big challenge where potential failure seems to lurk at every corner, maybe you've heard this advice before: "Be more confident." And most likely, this is what you think when you hear it: "If only it were that simple." But what is confidence? Take the belief that you are valuable, worthwhile, and capable, also known as self-esteem, add in the optimism that comes when you are certain of your abilities, and then empowered by these, act courageously to face a challenge head-on. This is confidence. It turns thoughts into action. So where does confidence even come from? There are several factors that impact confidence. One: what you're born with, such as your genes, which will impact things like the balance of neurochemicals in your brain. Two: how you're treated. This includes the social pressures of your environment. And three: the part you have control over, the choices you make, the risks you take, and how you think about and respond to challenges and setbacks. It isn't possible to completely untangle these three factors, but the personal choices we make certainly play a major role in confidence development. So, by keeping in mind a few practical tips, we do actually have the power to cultivate our own confidence. Tip 1: a quick fix. There are a few tricks that can give you an immediate confidence boost in the short term. Picture your success when you're beginning a difficult task, something as simple as listening to music with deep bass; it can promote feelings of power. You can even strike a powerful pose or give yourself a pep talk. Tip two: believe in your ability to improve. If you're looking for a long-term change, consider the way you think about your abilities and talents. Do you think they are fixed at birth, or that they can be developed, like a muscle? These beliefs matter because they can influence how you act when you're faced with setbacks. If you have a fixed mindset, meaning that you think your talents are locked in place, you might give up, assuming you've discovered something you're not very good at. But if you have a growth mindset and think your abilities can improve, a challenge is an opportunity to learn and grow. Neuroscience supports the growth mindset. The connections in your brain do get stronger and grow with study and practice. It also turns out, on average, people who have a growth mindset are more successful, getting better grades, and doing better in the face of challenges. Tip three: practice failure. Face it, you're going to fail sometimes. Everyone does. J.K. Rowling was rejected by twelve different publishers before one picked up "Harry Potter." The Wright Brothers built on history's failed attempts at flight, including some of their own, before designing a successful airplane. Studies show that those who fail regularly and keep trying anyway are better equipped to respond to challenges and setbacks in a constructive way. They learn how to try different strategies, ask others for advice, and perservere. So, think of a challenge you want to take on, realize it's not going to be easy, accept that you'll make mistakes, and be kind to yourself when you do. Give yourself a pep talk, stand up, and go for it. The excitement you'll feel knowing that whatever the result, you'll have gained greater knowledge and understanding. This is confidence. |
What is the Heisenberg Uncertainty Principle? | {0: 'I’m an Associate Professor in the Department of Physics and Astronomy at Union College, and I write books about science for non-scientists. I also blog about physics and other things at Forbes.com and ScienceBlogs.com. I have a BA in physics from Williams College and a Ph.D. in Chemical Physics from the University of Maryland, College Park (studying laser cooling at the National Institute of Standards and Technology in the lab of Bill Phillips, who shared the 1997 Nobel in Physics). I was a post-doc at Yale, and have been at Union since 2001. My books _How to Teach Physics to Your Dog_ and _How to Teach Relativity to Your Dog_ explain modern physics through imaginary conversations with my German Shepherd, Emmy, and my most recent book, _Eureka: Discovering Your Inner Scientist_ (Basic, 2014), explains how we use the process of science in everyday activities. I live in Niskayuna, NY with my wife, Kate Nepveu, our two kids, and Emmy, the Queen of Niskayuna.'} | TED-Ed | The Heisenberg Uncertainty Principle is one of a handful of ideas from quantum physics to expand into general pop culture. It says that you can never simultaneously know the exact position and the exact speed of an object and shows up as a metaphor in everything from literary criticism to sports commentary. Uncertainty is often explained as a result of measurement, that the act of measuring an object's position changes its speed, or vice versa. The real origin is much deeper and more amazing. The Uncertainty Principle exists because everything in the universe behaves like both a particle and a wave at the same time. In quantum mechanics, the exact position and exact speed of an object have no meaning. To understand this, we need to think about what it means to behave like a particle or a wave. Particles, by definition, exist in a single place at any instant in time. We can represent this by a graph showing the probability of finding the object at a particular place, which looks like a spike, 100% at one specific position, and zero everywhere else. Waves, on the other hand, are disturbances spread out in space, like ripples covering the surface of a pond. We can clearly identify features of the wave pattern as a whole, most importantly, its wavelength, which is the distance between two neighboring peaks, or two neighboring valleys. But we can't assign it a single position. It has a good probability of being in lots of different places. Wavelength is essential for quantum physics because an object's wavelength is related to its momentum, mass times velocity. A fast-moving object has lots of momentum, which corresponds to a very short wavelength. A heavy object has lots of momentum even if it's not moving very fast, which again means a very short wavelength. This is why we don't notice the wave nature of everyday objects. If you toss a baseball up in the air, its wavelength is a billionth of a trillionth of a trillionth of a meter, far too tiny to ever detect. Small things, like atoms or electrons though, can have wavelengths big enough to measure in physics experiments. So, if we have a pure wave, we can measure its wavelength, and thus its momentum, but it has no position. We can know a particles position very well, but it doesn't have a wavelength, so we don't know its momentum. To get a particle with both position and momentum, we need to mix the two pictures to make a graph that has waves, but only in a small area. How can we do this? By combining waves with different wavelengths, which means giving our quantum object some possibility of having different momenta. When we add two waves, we find that there are places where the peaks line up, making a bigger wave, and other places where the peaks of one fill in the valleys of the other. The result has regions where we see waves separated by regions of nothing at all. If we add a third wave, the regions where the waves cancel out get bigger, a fourth and they get bigger still, with the wavier regions becoming narrower. If we keep adding waves, we can make a wave packet with a clear wavelength in one small region. That's a quantum object with both wave and particle nature, but to accomplish this, we had to lose certainty about both position and momentum. The positions isn't restricted to a single point. There's a good probability of finding it within some range of the center of the wave packet, and we made the wave packet by adding lots of waves, which means there's some probability of finding it with the momentum corresponding to any one of those. Both position and momentum are now uncertain, and the uncertainties are connected. If you want to reduce the position uncertainty by making a smaller wave packet, you need to add more waves, which means a bigger momentum uncertainty. If you want to know the momentum better, you need a bigger wave packet, which means a bigger position uncertainty. That's the Heisenberg Uncertainty Principle, first stated by German physicist Werner Heisenberg back in 1927. This uncertainty isn't a matter of measuring well or badly, but an inevitable result of combining particle and wave nature. The Uncertainty Principle isn't just a practical limit on measurment. It's a limit on what properties an object can have, built into the fundamental structure of the universe itself. |
Why the octopus brain is so extraordinary | null | TED-Ed | What could octopuses possibly have in common with us? After all, they don't have lungs, spines, or even a plural noun we can all agree on. But what they do have is the ability to solve puzzles, learn through observation, and even use tools, just like some other animals we know. And what makes octopus intelligence so amazing is that it comes from a biological structure completely different from ours. The 200 or so species of octopuses are mollusks belonging to the order cephalopoda, Greek for head-feet. Those heads contain impressively large brains, with a brain to body ratio similar to that of other intelligent animals, and a complex nervous system with about as many neurons as that of a dog. But instead of being centralized in the brain, these 500 million neurons are spread out in a network of interconnected ganglia organized into three basic structures. The central brain only contains about 10% of the neurons, while the two huge optic lobes contain about 30%. The other 60% are in the tentacles, which for humans would be like our arms having minds of their own. This is where things get even more interesting. Vertebrates like us have a rigid skeleton to support our bodies, with joints that allow us to move. But not all types of movement are allowed. You can't bend your knee backwards, or bend your forearm in the middle, for example. Cephalopods, on the other hand, have no bones at all, allowing them to bend their limbs at any point and in any direction. So shaping their tentacles into any one of the virtually limitless number of possible arrangements is unlike anything we are used to. Consider a simple task, like grabbing and eating an apple. The human brain contains a neurological map of our body. When you see the apple, your brain's motor center activates the appropriate muscles, allowing you to reach out with your arm, grab it with your hand, bend your elbow joint, and bring it to your mouth. For an octopus, the process is quite different. Rather than a body map, the cephalopod brain has a behavior library. So when an octopus sees food, its brain doesn't activate a specific body part, but rather a behavioral response to grab. As the signal travels through the network, the arm neurons pick up the message and jump into action to command the movement. As soon as the arm touches the food, a muscle activation wave travels all the way through the arm to its base, while the arm sends back another wave from the base to the tip. The signals meet halfway between the food and the base of the arm, letting it know to bend at that spot. What all this means is that each of an octopus's eight arms can essentially think for itself. This gives it amazing flexibility and creativity when facing a new situation or problem, whether its opening a bottle to reach food, escaping through a maze, moving around in a new environment, changing the texture and the color of its skin to blend into the scenery, or even mimicking other creatures to scare away enemies. Cephalopods may have evolved complex brains long before our vertebrate relatives. And octopus intelligence isn't just useful for octopuses. Their radically different nervous system and autonomously thinking appendages have inspired new research in developing flexible robots made of soft materials. And studying how intelligence can arise along such a divergent evolutionary path can help us understand more about intelligence and consciousness in general. Who knows what other forms of intelligent life are possible, or how they process the world around them. |
A brief history of melancholy | null | TED-Ed | Sadness is part of the human experience, but for centuries there has been vast disagreement over what exactly it is and what, if anything, to do about it. In its simplest terms, sadness is often thought of as the natural reaction to a difficult situation. You feel sad when a friend moves away or when a pet dies. When a friend says, "I'm sad," you often respond by asking, "What happened?" But your assumption that sadness has an external cause outside the self is a relatively new idea. Ancient Greek doctors didn't view sadness that way. They believed it was a dark fluid inside the body. According to their humoral system, the human body and soul were controlled by four fluids, known as humors, and their balance directly influenced a person's health and temperament. Melancholia comes from melaina kole, the word for black bile, the humor believed to cause sadness. By changing your diet and through medical practices, you could bring your humors into balance. Even though we now know much more about the systems that govern the human body, these Greek ideas about sadness resonate with current views, not on the sadness we all occasionally feel, but on clinical depression. Doctors believe that certain kinds of long-term, unexplained emotional states are at least partially related to brain chemistry, the balance of various chemicals present inside the brain. Like the Greek system, changing the balance of these chemicals can deeply alter how we respond to even extremely difficult circumstances. There's also a long tradition of attempting to discern the value of sadness, and in that discussion, you'll find a strong argument that sadness is not only an inevitable part of life but an essential one. If you've never felt melancholy, you've missed out on part of what it means to be human. Many thinkers contend that melancholy is necessary in gaining wisdom. Robert Burton, born in 1577, spent his life studying the causes and experience of sadness. In his masterpiece "The Anatomy of Melancholy," Burton wrote, "He that increaseth wisdom increaseth sorrow." The Romantic poets of the early 19th century believed melancholy allows us to more deeply understand other profound emotions, like beauty and joy. To understand the sadness of the trees losing their leaves in the fall is to more fully understand the cycle of life that brings flowers in the spring. But wisdom and emotional intelligence seem pretty high on the hierarchy of needs. Does sadness have value on a more basic, tangible, maybe even evolutionary level? Scientists think that crying and feeling withdrawn is what originally helped our ancestors secure social bonds and helped them get the support they needed. Sadness, as opposed to anger or violence, was an expression of suffering that could immediately bring people closer to the suffering person, and this helped both the person and the larger community to thrive. Perhaps sadness helped generate the unity we needed to survive, but many have wondered whether the suffering felt by others is anything like the suffering we experience ourselves. The poet Emily Dickinson wrote, "I measure every Grief I meet With narrow, probing Eyes - I wonder if it weighs like MIne - Or has an Easier size." And in the 20th century, medical anthropologists, like Arthur Kleinman, gathered evidence from the way people talk about pain to suggest that emotions aren't universal at all, and that culture, particularly the way we use language, can influence how we feel. When we talk about heartbreak, the feeling of brokenness becomes part of our experience, where as in a culture that talks about a bruised heart, there actually seems to be a different subjective experience. Some contemporary thinkers aren't interested in sadness' subjectivity versus universality, and would rather use technology to eliminate suffering in all its forms. David Pearce has suggested that genetic engineering and other contemporary processes cannot only alter the way humans experience emotional and physical pain, but that world ecosystems ought to be redesigned so that animals don't suffer in the wild. He calls his project "paradise engineering." But is there something sad about a world without sadness? Our cavemen ancestors and favorite poets might not want any part of such a paradise. In fact, the only things about sadness that seem universally agreed upon are that it has been felt by most people throughout time, and that for thousands of years, one of the best ways we have to deal with this difficult emotion is to articulate it, to try to express what feels inexpressable. In the words of Emily Dickinson, "'Hope' is the thing with feathers - That perches in the soul - "And sings the tune without the words - And never stops - at all -" |
Meet the tardigrade, the toughest animal on Earth | null | TED-Ed | Without water, a human can only survive for about 100 hours. But there's a creature so resilient that it can go without it for decades. This one millimeter animal can survive both the hottest and coldest environments on Earth, and can even withstand high levels of radiation. This is the tardigrade, and it's one of the toughest creatures on Earth, even if it does look more like a chubby, eight-legged gummy bear. Most organisms need water to survive. Water allows metabolism to occur, which is the process that drives all the biochemical reactions that take place in cells. But creatures like the tardigrade, also known as the water bear, get around this restriction with a process called anhydrobiosis, from the Greek meaning life without water. And however extraordinary, tardigrades aren't alone. Bacteria, single-celled organisms called archaea, plants, and even other animals can all survive drying up. For many tardigrades, this requires that they go through something called a tun state. They curl up into a ball, pulling their head and eight legs inside their body and wait until water returns. It's thought that as water becomes scarce and tardigrades enter their tun state, they start synthesize special molecules, which fill the tardigrade's cells to replace lost water by forming a matrix. Components of the cells that are sensitive to dryness, like DNA, proteins, and membranes, get trapped in this matrix. It's thought that this keeps these molecules locked in position to stop them from unfolding, breaking apart, or fusing together. Once the organism is rehydrated, the matrix dissolves, leaving behind undamaged, functional cells. Beyond dryness, tardigrades can also tolerate other extreme stresses: being frozen, heated up past the boiling point of water, high levels of radiation, and even the vacuum of outer space. This has led to some erroneous speculation that tardigrades are extraterrestrial beings. While that's fun to think about, scientific evidence places their origin firmly on Earth where they've evolved over time. In fact, this earthly evolution has given rise to over 1100 known species of tardigrades and there are probably many others yet to be discovered. And because tardigrades are so hardy, they exist just about everywhere. They live on every continent, including Antarctica. And they're in diverse biomes including deserts, ice sheets, the sea, fresh water, rainforests, and the highest mountain peaks. But you can find tardigrades in the most ordinary places, too, like moss or lichen found in yards, parks, and forests. All you need to find them is a little patience and a microscope. Scientists are now to trying to find out whether tardigrades use the tun state, their anti-drying technique, to survive other stresses. If we can understand how they, and other creatures, stabilize their sensitive biological molecules, perhaps we could apply this knowledge to help us stabilize vaccines, or to develop stress-tolerant crops that can cope with Earth's changing climate. And by studying how tardigrades survive prolonged exposure to the vacuum of outer space, scientists can generate clues about the environmental limits of life and how to safeguard astronauts. In the process, tardigrades could even help us answer a critical question: could life survive on planets much less hospitable than our own? |
Why are human bodies asymmetrical? | null | TED-Ed | Symmetry is everywhere in nature, and we usually associate it with beauty: a perfectly shaped leaf, or a butterfly with intricate patterns mirrored on each wing. But it turns out that asymmetry is pretty important, too, and more common than you might think, from crabs with one giant pincer claw to snail species whose shells' always coil in the same direction. Some species of beans only climb up their trellises clockwise, others, only counterclockwise, and even though the human body looks pretty symmetrical on the outside, it's a different story on the inside. Most of your vital organs are arranged asymmetrically. The heart, stomach, spleen, and pancreas lie towards the left. The gallbladder and most of your liver are on the right. Even your lungs are different. The left one has two lobes, and the right one has three. The two sides of your brain look similar, but function differently. Making sure this asymmetry is distributed the right way is critical. If all your internal organs are flipped, a condition called situs inversus, it's often harmless. But incomplete reversals can be fatal, especially if the heart is involved. But where does this asymmetry come from, since a brand-new embryo looks identical on the right and left. One theory focuses on a small pit on the embryo called a node. The node is lined with tiny hairs called cilia, while tilt away from the head and whirl around rapidly, all in the same direction. This synchronized rotation pushes fluid from the right side of the embryo to the left. On the node's left-hand rim, other cilia sense this fluid flow and activate specific genes on the embryo's left side. These genes direct the cells to make certain proteins, and in just a few hours, the right and left sides of the embryo are chemically different. Even though they still look the same, these chemical differences are eventually translated into asymmetric organs. Asymmetry shows up in the heart first. It begins as a straight tube along the center of the embryo, but when the embryo is around three weeks old, the tube starts to bend into a c-shape and rotate towards the right side of the body. It grows different structures on each side, eventually turning into the familiar asymmetric heart. Meanwhile, the other major organs emerge from a central tube and grow towards their ultimate positions. But some organisms, like pigs, don't have those embryonic cilia and still have asymmetric internal organs. Could all cells be intrinsically asymmetric? Probably. Bacterial colonies grow lacy branches that all curl in the same direction, and human cells cultured inside a ring-shaped boundary tend to line up like the ridges on a cruller. If we zoom in even more, we see that many of cells' basic building blocks, like nucleic acids, proteins, and sugars, are inherently asymmetric. Proteins have complex asymmetric shapes, and those proteins control which way cells migrate and which way embryonic cilia twirl. These biomolecules have a property called chirality, which means that a molecule and its mirror image aren't identical. Like your right and left hands, they look the same, but trying to put your right in your left glove proves they're not. This asymmetry at the molecular level is reflected in asymmetric cells, asymmetric embryos, and finally asymmetric organisms. So while symmetry may be beautiful, asymmetry holds an allure of its own, found in its graceful whirls, its organized complexity, and its striking imperfections. |
Why are some people left-handed? | null | TED-Ed | If you know an older left-handed person, chances are they had to learn to write or eat with their right hand. And in many parts of the world, it's still common practice to force children to use their "proper" hand. Even the word for right also means correct or good, not just in English, but many other languages, too. But if being left-handed is so wrong, then why does it happen in the first place? Today, about 1/10 of the world's population are left-handed. Archeological evidence shows that it's been that way for as long as 500,000 years, with about 10% of human remains showing the associated differences in arm length and bone density, and some ancient tools and artifacts showing evidence of left-hand use. And despite what many may think, handedness is not a choice. It can be predicted even before birth based on the fetus' position in the womb. So, if handedness is inborn, does that mean it's genetic? Well, yes and no. Identical twins, who have the same genes, can have different dominant hands. In fact, this happens as often as it does with any other sibling pair. But the chances of being right or left-handed are determined by the handedness of your parents in surprisingly consistent ratios. If your father was left-handed but your mother was right-handed, you have a 17% chance of being born left-handed, while two righties will have a left-handed child only 10% of the time. Handedness seems to be determined by a roll of the dice, but the odds are set by your genes. All of this implies there's a reason that evolution has produced this small proportion of lefties, and maintained it over the course of millennia. And while there have been several theories attempting to explain why handedness exists in the first place, or why most people are right-handed, a recent mathematical model suggests that the actual ratio reflects a balance between competitive and cooperative pressures on human evolution. The benefits of being left-handed are clearest in activities involving an opponent, like combat or competitive sports. For example, about 50% of top hitters in baseball have been left-handed. Why? Think of it as a surprise advantage. Because lefties are a minority to begin with, both right-handed and left-handed competitors will spend most of their time encountering and practicing against righties. So when the two face each other, the left-hander will be better prepared against this right-handed opponent, while the righty will be thrown off. This fighting hypothesis, where an imbalance in the population results in an advantage for left-handed fighters or athletes, is an example of negative frequency-dependent selection. But according to the principles of evolution, groups that have a relative advantage tend to grow until that advantage disappears. If people were only fighting and competing throughout human evolution, natural selection would lead to more lefties being the ones that made it until there were so many of them, that it was no longer a rare asset. So in a purely competitive world, 50% of the population would be left-handed. But human evolution has been shaped by cooperation, as well as competition. And cooperative pressure pushes handedness distribution in the opposite direction. In golf, where performance doesn't depend on the opponent, only 4% of top players are left-handed, an example of the wider phenomenon of tool sharing. Just as young potential golfers can more easily find a set of right-handed clubs, many of the important instruments that have shaped society were designed for the right-handed majority. Because lefties are worse at using these tools, and suffer from higher accident rates, they would be less successful in a purely cooperative world, eventually disappearing from the population. So by correctly predicting the distribution of left-handed people in the general population, as well as matching data from various sports, the model indicates that the persistence of lefties as a small but stable minority reflects an equilibrium that comes from competitive and cooperative effects playing out simultaneously over time. And the most intriguing thing is what the numbers can tell us about various populations. From the skewed distribution of pawedness in cooperative animals, to the slightly larger percentage of lefties in competitive hunter-gatherer societies, we may even find that the answers to some puzzles of early human evolution are already in our hands. |
Is radiation dangerous? | null | TED-Ed | When we hear the word radiation, it's tempting to picture huge explosions and frightening mutations, but that's not the full story. Radiation also applies to rainbows and a doctor examining an x-ray. So what is radiation really, and how much should we worry about its effects? The answer begins with understanding that the word radiation describes two very different scientific phenomena: electromagnetic radiation and nuclear radiation. Electromagnetic radiation is pure energy consisting of interacting electrical and magnetic waves oscillating through space. As these waves oscillate faster, they scale up in energy. At the lower end of the spectrum, there's radio, infrared, and visible light. At the higher end are ultraviolet, X-ray, and gamma rays. Modern society is shaped by sending and detecting electromagnetic radiation. We might download an email to our phone via radio waves to open an image of an X-ray print, which we can see because our screen emits visible light. Nuclear radiation, on the other hand, originates in the atomic nucleus, where protons repel each other due to their mutually positive charges. A phenomenon known as the strong nuclear force struggles to overcome this repulsion and keep the nucleus intact. However, some combinations of protons and neutrons, known as isotopes, remain unstable, or radioactive. They will randomly eject matter and/or energy, known as nuclear radiation, to achieve greater stability. Nuclear radiation comes from natural sources, like radon, a gas which seeps up from the ground. We also refine naturally occurring radioactive ores to fuel nuclear power plants. Even bananas contain trace amounts of a radioactive potassium isotope. So if we live in a world of radiation, how can we escape its dangerous effects? To start, not all radiation is hazardous. Radiation becomes risky when it rips atoms' electrons away upon impact, a process that can damage DNA. This is known as ionizing radiation because an atom that has lost or gained electrons is called an ion. All nuclear radiation is ionizing, while only the highest energy electromagnetic radiation is. That includes gamma rays, X-rays, and the high-energy end of ultraviolet. That's why as an extra precaution during X-rays, doctors shield body parts they don't need to examine, and why beach-goers use sunscreen. In comparison, cell phones and microwaves operate at the lower end of the spectrum, so there is no risk of ionizing radiation from their use. The biggest health risk occurs when lots of ionizing radiation hits us in a short time period, also known as an acute exposure. Acute exposures overwhelm the body's natural ability to repair the damage. This can trigger cancers, cellular dysfunction, and potentially even death. Fortunately, acute exposures are rare, but we are exposed daily to lower levels of ionizing radiation from both natural and man-made sources. Scientists have a harder time quantifying these risks. Your body often repairs damage from small amounts ionizing radiation, and if it can't, the results of damage may not manifest for a decade or more. One way scientists compare ionizing radiation exposure is a unit called the sievert. An acute exposure to one sievert will probably cause nausea within hours, and four sieverts could be fatal. However, our normal daily exposures are far lower. The average person receives 6.2 millisieverts of radiation from all sources annually, around a third due to radon. At only five microsieverts each, you'd need to get more than 1200 dental X-rays to rack up your annual dosage. And remember that banana? If you could absorb all the banana's radiation, you'd need around 170 a day to hit your annual dosage. We live in a world of radiation. However, much of that radiation is non-ionizing. For the remainder that is ionizing, our exposures are usually low, and choices like getting your home tested for radon and wearing sunscreen can help reduce the associated health risks. Marie Curie, one of the early radiation pioneers, summed up the challenge as follows: "Nothing in life is to be feared, it is only to be understood. Now is the time to understand more, so that we may fear less." |
Does grammar matter? | null | TED-Ed | You're telling a friend an amazing story, and you just get to the best part when suddenly he interrupts, "The alien and I," not "Me and the alien." Most of us would probably be annoyed, but aside from the rude interruption, does your friend have a point? Was your sentence actually grammatically incorrect? And if he still understood it, why does it even matter? From the point of view of linguistics, grammar is a set of patterns for how words are put together to form phrases or clauses, whether spoken or in writing. Different languages have different patterns. In English, the subject normally comes first, followed by the verb, and then the object, while in Japanese and many other languages, the order is subject, object, verb. Some scholars have tried to identify patterns common to all languages, but apart from some basic features, like having nouns or verbs, few of these so-called linguistic universals have been found. And while any language needs consistent patterns to function, the study of these patterns opens up an ongoing debate between two positions known as prescriptivism and descriptivism. Grossly simplified, prescriptivists think a given language should follow consistent rules, while descriptivists see variation and adaptation as a natural and necessary part of language. For much of history, the vast majority of language was spoken. But as people became more interconnected and writing gained importance, written language was standardized to allow broader communication and ensure that people in different parts of a realm could understand each other. In many languages, this standard form came to be considered the only proper one, despite being derived from just one of many spoken varieties, usually that of the people in power. Language purists worked to establish and propagate this standard by detailing a set of rules that reflected the established grammar of their times. And rules for written grammar were applied to spoken language, as well. Speech patterns that deviated from the written rules were considered corruptions, or signs of low social status, and many people who had grown up speaking in these ways were forced to adopt the standardized form. More recently, however, linguists have understood that speech is a separate phenomenon from writing with its own regularities and patterns. Most of us learn to speak at such an early age that we don't even remember it. We form our spoken repertoire through unconscious habits, not memorized rules. And because speech also uses mood and intonation for meaning, its structure is often more flexible, adapting to the needs of speakers and listeners. This could mean avoiding complex clauses that are hard to parse in real time, making changes to avoid awkward pronounciation, or removing sounds to make speech faster. The linguistic approach that tries to understand and map such differences without dictating correct ones is known as descriptivism. Rather than deciding how language should be used, it describes how people actually use it, and tracks the innovations they come up with in the process. But while the debate between prescriptivism and descriptivism continues, the two are not mutually exclusive. At its best, prescriptivism is useful for informing people about the most common established patterns at a given point in time. This is important, not only for formal contexts, but it also makes communication easier between non-native speakers from different backgrounds. Descriptivism, on the other hand, gives us insight into how our minds work and the instinctive ways in which we structure our view of the world. Ultimately, grammar is best thought of as a set of linguistic habits that are constantly being negotiated and reinvented by the entire group of language users. Like language itself, it's a wonderful and complex fabric woven through the contributions of speakers and listeners, writers and readers, prescriptivists and descriptivists, from both near and far. |
How to spot a pyramid scheme | null | TED-Ed | In 2004, a new company called Vemma Nutrition started offering a life-changing opportunity to earn full time income for part time work. Vemma’s offer was open to everybody, regardless of prior experience or education. There were only two steps to start get started earning: purchase a $500-600 kit of their liquid nutrition products, and recruit two more members to do the same. Vemma Nutrition Company grew quickly, becoming a global operation that brought in 30,000 new members per month at its peak. There was just one problem— while the company generated $200 million of annual revenue by 2013, the vast majority of participants earned less than they paid in. Vemma was eventually charged with operating a pyramid scheme: a common type of fraud where members make money by recruiting more people to buy in. Typically, the founder solicits an initial group of people to buy in and promote the scheme. They are then encouraged to recruit others and promised part of the money those people invest, while the founder also takes a share. The pattern repeats for each group of new participants, with money from recent arrivals funneled to those who recruited them. This differs from a Ponzi scheme, where the founders recruit new members and secretly use their fees to pay existing members, who think the payments come from a legitimate investment. As a pyramid scheme grows, it becomes increasingly difficult for new recruits to make money. That’s because the number of participants expands exponentially. Take a structure where each person has to recruit six more to earn a profit. The founder recruits six people to start, and each of them recruits six more. There are 36 people in that second round of recruits, who then each recruit 6 people— a total of 216 new recruits. By the twelfth round of recruiting, the 2.1 billion newest members would have to recruit over 13 billion more people total to make money– more than the entire world population. In this scenario, the most recent recruits, over 80% of the scheme’s participants, lose all the money they paid in. And in real life, many earlier joiners lose out too. Pyramid schemes are illegal in most countries, but they can be difficult to detect. They are presented as many different things, including gifting groups, investment clubs, and multi-level marketing businesses. The distinction between pyramid schemes and legitimate multi-level marketing can be particularly hazy. In theory, the difference is that the members of the multi-level marketing companies primarily earn compensation from selling a particular product or a service to retail customers, while pyramid schemes primarily compensate members for recruitment of new sellers. In practice, though, many multi-level marketing companies make it all but impossible for members to profit purely through sales. And many pyramid schemes, like Vemma Nutrition, disguise themselves as legal multi-level marketing businesses, using a product or service to hide the pay-and-recruit structure. Many pyramid schemes also capitalize on already existing trust within churches, immigrant communities, or other tightly knit groups. The first few members are encouraged to report a good experience before they actually start making a profit. Others in their network follow their example, and the schemes balloon in size before it comes clear that most members aren’t actually profiting. Often, the victims are embarrassed into silence. Pyramid schemes entice people with the promise of opportunity and empowerment. So when members don’t end up making money, they can blame themselves rather than the scheme, thinking they weren’t tenacious enough to earn the returns promised. Some victims keep trying, investing in multiple schemes, and losing money each time. In spite of all these factors, there are ways to spot a pyramid scheme. Time pressure is one red flag— be wary of directives to “act now or miss a once-in-a-lifetime opportunity.” Promises of large, life-altering amounts of income are also suspect. And finally, a legitimate multi-level marketing business shouldn’t require members to pay for the opportunity to sell a product or service. Pyramid schemes can be incredibly destructive to individuals, communities, and even entire countries. But you can fight fire with fire by sending this video to three people you know, and encouraging them to do the same. |
How does income affect childhood brain development? | {0: "Kimberly Noble, MD, PhD, studies how socioeconomic inequality relates to children's cognitive and brain development."} | TED Salon: Education Everywhere | What I'm about to share with you are findings from a study of the brains of more than 1,000 children and adolescents. Now, these were children who were recruited from diverse homes around the United States, and this picture is an average of all of their brains. The front of this average brain is on your left and the back of this average brain is on your right. Now, one of the things we were very interested in was the surface area of the cerebral cortex, or the thin, wrinkly layer on the outer surface of the brain that does most of the cognitive heavy lifting. And that's because past work by other scientists has suggested that in many cases, a larger cortical surface area is often associated with higher intelligence. Now, in this study, we found one factor that was associated with the cortical surface area across nearly the entire surface of the brain. That factor was family income. Now, here, every point you see in color is a point where higher family income was associated with a larger cortical surface area in that spot. And there were some regions, shown here in yellow, where that association was particularly pronounced. And those are regions that we know support a certain set of cognitive skills: language skills like vocabulary and reading as well as the ability to avoid distraction and exert self-control. And that's important, because those are the very skills that children living in poverty are most likely to struggle with. In fact, a child living with poverty is likely to perform worse on tests of language and impulse control before they even turn two. Now, there are a few points I'd like to highlight about this study. Number one: this link between family income and children's brain structure was strongest at the lowest income levels. So that means that dollar for dollar, relatively small differences in family income were associated with proportionately greater differences in brain structure among the most disadvantaged families. And intuitively, that makes sense, right? An extra 20,000 dollars for a family earning, say, 150,000 dollars a year would certainly be nice, but probably not game-changing, whereas an extra 20,000 dollars for a family only earning 20,000 dollars a year would likely make a remarkable difference in their day-to-day lives. Now, the second point I'd like to highlight is that this link between family income and children's brain structure didn't depend on the children's age, it didn't depend on their sex and it didn't depend on their race or ethnicity. And the final point — and this one's key — there was tremendous variability from one child to the next, by which I mean there were plenty of children from higher-income homes with smaller brain surfaces and plenty of children from lower-income homes with larger brain surfaces. Here's an analogy. We all know that in childhood, boys tend to be taller than girls, but go into any elementary school classroom, and you'll find some girls who are taller than some boys. So while growing up in poverty is certainly a risk factor for a smaller brain surface, in no way can I know an individual child's family income and know with any accuracy what that particular child's brain would look like. I want you to imagine, for a moment, two children. One is a young child born into poverty in America; the other is also an American child, but one who was born into more fortunate circumstances. Now, at birth, we find absolutely no differences in how their brains work. But by the time those two kids are ready to start kindergarten, we know that the child living in poverty is likely to have cognitive scores that are, on average, 60 percent lower than those of the other child. Later on, that child living in poverty will be five times more likely to drop out of high school, and if she does graduate high school, she'll be less likely to earn a college degree. By the time those two kids are 35 years old, if the first child spent her entire childhood living in poverty, she is up to 75 times more likely to be poor herself. But it doesn't have to be that way. As a neuroscientist, one of things I find most exciting about the human brain is that our experiences change our brains. Now, this concept, known as neuroplasticity, means that these differences in children's brain structure don't doom a child to a life of low achievement. The brain is not destiny. And if a child's brain can be changed, then anything is possible. As a society, we spend billions of dollars each year, educating our children. So what can we tell schools, teachers and parents who want to help support kids from disadvantaged backgrounds to do their best in school and in life? Well, emerging science suggests that growing up in poverty is associated with a host of different experiences and that these experiences in turn may work together to help shape brain development and ultimately help kids learn. And so if this is right, it begs the question: Where along this pathway can we step in and provide help? So let's consider first intervening at the level of learning itself — most commonly through school-based initiatives. Now, should we be encouraging teachers to focus on the kinds of skills that disadvantaged kids are most likely to struggle with? Of course. The importance of high-quality education based in scientific evidence really can't be overstated. And there are a number of examples of excellent interventions targeting things like literacy or self-regulation that do in fact improve kids' cognitive development and their test scores. But as any intervention scientist doing this work would tell you, this work is challenging. It's hard to implement high-quality, evidence-based education. And it can be labor-intensive, it's sometimes costly. And in many cases, these disparities in child development emerge early — well before the start of formal schooling — sometimes when kids are just toddlers. And so I would argue: school is very important, but if we're focusing all of our policy efforts on formal schooling, we're probably starting too late. So what about taking a step back and focusing on trying to change children's experiences? What particular experiences are associated with growing up in poverty and might be able to be targeted to promote brain development and learning outcomes for kids? Of course, there are many, right? Nutrition, access to health care, exposure to second-hand smoke or lead, experience of stress or discrimination, to name a few. In my laboratory, we're particularly focused on a few types of experiences that we believe may be able to be targeted to promote children's brain development and ultimately improve their learning outcomes. As one example, take something I'll call the home language environment, by which I mean, we know that the number of words kids hear and the number of conversations they're engaged in every day can vary tremendously. By some estimates, kids from more advantaged backgrounds hear an average of 30 million more spoken words in the first few years of life compared to kids from less advantaged backgrounds. Now, in our work, we're finding that kids who experience more back-and-forth, responsive conversational turns tend to have a larger brain surface in parts of the brain that we know are responsible for language and reading skills. And in fact, the number of conversations they hear seems to matter a little bit more than the sheer number of words they hear. So one tantalizing possibility is that we should be teaching parents not just to talk a lot, but to actually have more conversations with their children. In this way, it's possible that we'll promote brain development and perhaps their kids' language and reading skills. And in fact, a number of scientists are testing that exciting possibility right now. But of course, we all know that growing up in poverty is associated with lots of different experiences beyond just how many conversations kids are having. So how do we choose what else to focus on? The list can be overwhelming. There are a number of high-quality interventions that do try to change children's experience, many of which are quite effective. But again, just like school-based initiatives, this is hard work. It can be challenging, it can be labor-intensive, sometimes costly ... and on occasion, it can be somewhat patronizing for scientists to swoop in and tell a family what they need to change in order for their child to succeed. So I want to share an idea with you. What if we tried to help young children in poverty by simply giving their families more money? I'm privileged to be working with a team of economists, social policy experts and neuroscientists in leading Baby's First Years, the first-ever randomized study to test whether poverty reduction causes changes in children's brain development. Now, the ambition of the study is large, but the premise is actually quite simple. In May of 2018, we began recruiting 1,000 mothers living below the federal poverty line shortly after they gave birth in a number of American hospitals. Upon enrolling in our study, all mothers receive an unconditional monthly cash gift for the first 40 months of their children's lives, and they're free to use this money however they like. But importantly, mothers are being randomized, so some mothers are randomized to receive a nominal monthly cash gift and others are randomized to receive several hundred dollars each month, an amount that we believe is large enough to make a difference in their day-to-day lives, in most cases increasing their monthly income by 20 to 25 percent. So in this way, we're hoping to finally move past questions of how poverty is correlated with child development and actually be able to test whether reducing poverty causes changes in children's cognitive, emotional and brain development in the first three years of life — the very time when we believe the developing brain may be most malleable to experience. Now, we won't have definitive results from this study for several years, and if nothing else, 1,000 newborns and their moms will have a bit more cash each month that they tell us they very much need. But what if it turns out that a cost-effective way to help young children in poverty is to simply give their moms more money? If our hypotheses are borne out, it's our hope that results from this work will inform debates about social services that have the potential to effect millions of families with young children. Because while income may not be the only or even the most important factor in determining children's brain development, it may be one that, from a policy perspective, can be easily addressed. Put simply, if we can show that reducing poverty changes how children's brains develop and that leads to meaningful policy changes, then a young child born into poverty today may have a much better shot at a brighter future. Thank you. (Applause) |
Public art that turns cities into playgrounds of the imagination | {0: 'Helen Marriage cofounded a company that specializes in creating disruptive, whole-city arts events that surprise and delight everyone who comes across them.'} | TEDWomen 2018 | We live in a world increasingly tyrannized by the screen, by our phones, by our tablets, by our televisions and our computers. We can have any experience that we want, but feel nothing. We can have as many friends as we want, but have nobody to shake hands with. I want to take you to a different kind of world, the world of the imagination, where, using this most powerful tool that we have, we can transform both our physical surroundings, but in doing so, we can change forever how we feel and how we feel about the people that we share the planet with. My company, Artichoke, which I cofounded in 2006, was set up to create moments. We all have moments in our lives, and when we're on our deathbeds, we're not going to remember the daily commute to work on the number 38 bus or our struggle to find a parking space every day when we go to the shop. We're going to remember those moments when our kid took their first step or when we got picked for the football team or when we fell in love. So Artichoke exists to create moving, ephemeral moments that transform the physical world using the imagination of the artist to show us what is possible. We create beauty amongst ruins. We reexamine our history. We create moments to which everyone is invited, either to witness or to take part. It all started for me way back in the 1990s, when I was appointed as festival director in the tiny British city of Salisbury. You'll probably have heard of it. Here's the Salisbury Cathedral, and here's the nearby Stonehenge Monument, which is world-famous. Salisbury is a city that's been dominated for hundreds of years by the Church, the Conservative Party and the army. It's a place where people really love to observe the rules. So picture me on my first year in the city, cycling the wrong way down a one-way street, late. I'm always late. It's a wonder I've even turned up today. (Laughter) A little old lady on the sidewalk helpfully shouted at me, "My dear, you're going the wrong way!" Charmingly — I thought — I said, "Yeah, I know." "I hope you die!" she screamed. (Laughter) And I realized that this was a place where I was in trouble. And yet, a year later, persuasion, negotiation — everything I could deploy — saw me producing the work. Not a classical concert in a church or a poetry reading, but the work of a French street theater company who were telling the story of Faust, "Mephistomania," on stilts, complete with handheld pyrotechnics. The day after, the same little old lady stopped me in the street and said, "Were you responsible for last night?" I backed away. (Laughter) "Yes." "When I heard about it," she said, "I knew it wasn't for me. But Helen, my dear, it was." So what had happened? Curiosity had triumphed over suspicion, and delight had banished anxiety. So I wondered how one could transfer these ideas to a larger stage and started on a journey to do the same kind of thing to London. Imagine: it's a world city. Like all our cities, it's dedicated to toil, trade and traffic. It's a machine to get you to work on time and back, and we're all complicit in wanting the routines to be fixed and for everybody to be able to know what's going to happen next. And yet, what if this amazing city could be turned into a stage, a platform for something so unimaginable that would somehow transform people's lives? We do these things often in Britain. I'm sure you do them wherever you're from. Here's Horse Guards Parade. And here's something that we do often. It's always about winning things. It's about the marathon or winning a war or a triumphant cricket team coming home. We close the streets. Everybody claps. But for theater? Not possible. Except a story told by a French company: a saga about a little girl and a giant elephant that came to visit for four days. And all I had to do was persuade the public authorities that shutting the city for four days was something completely normal. (Laughter) No traffic, just people enjoying themselves, coming out to marvel and witness this extraordinary artistic endeavor by the French theater company Royal de Luxe. It was a seven-year journey, with me saying to a group of men — almost always men — sitting in a room, "Eh, it's like a fairy story with a little girl and this giant elephant, and they come to town for four days and everybody gets to come and watch and play." And they would go, "Why would we do this? Is it for something? Is it celebrating a presidential visit? Is it the Entente Cordiale between France and England? Is it for charity? Are you trying to raise money?" And I'd say, "None of these things." And they'd say, "Why would we do this?" But after four years, this magic trick, this extraordinary thing happened. I was sitting in the same meeting I'd been to for four years, saying, "Please, please, may I?" Instead of which, I didn't say, "Please." I said, "This thing that we've been talking about for such a long time, it's happening on these dates, and I really need you to help me." This magic thing happened. Everybody in the room somehow decided that somebody else had said yes. (Laughter) (Applause) They decided that they were not being asked to take responsibility, or maybe the bus planning manager was being asked to take responsibility for planning the bus diversions, and the council officer was being asked to close the roads, and the transport for London people were being asked to sort out the Underground. All these people were only being asked to do the thing that they could do that would help us. Nobody was being asked to take responsibility. And I, in my innocence, thought, "Well, I'll take responsibility," for what turned out to be a million people on the street. It was our first show. (Applause) It was our first show, and it changed the nature of the appreciation of culture, not in a gallery, not in a theater, not in an opera house, but live and on the streets, transforming public space for the broadest possible audience, people who would never buy a ticket to see anything. So there we were. We'd finished, and we've continued to produce work of this kind. As you can see, the company's work is astonishing, but what's also astonishing is the fact that permission was granted. And you don't see any security. And this was nine months after terrible terrorist bombings that had ripped London apart. So I began to wonder whether it was possible to do this kind of stuff in even more complicated circumstances. We turned our attention to Northern Ireland, the North of Ireland, depending on your point of view. This is a map of England, Scotland, Wales and Ireland, the island to the left. For generations, it's been a place of conflict, the largely Catholic republic in the south and the largely Protestant loyalist community — hundreds of years of conflict, British troops on the streets for over 30 years. And now, although there is a peace process, this is today in this city, called Londonderry if you're a loyalist, called Derry if you're a Catholic. But everybody calls it home. And I began to wonder whether there was a way in which the community tribalism could be addressed through art and the imagination. This is what the communities do, every summer, each community. This is a bonfire filled with effigies and insignia from the people that they hate on the other side. This is the same from the loyalist community. And every summer, they burn them. They're right in the center of town. So we turned to here, to the Nevada desert, to Burning Man, where people also do bonfires, but with a completely different set of values. Here you see the work of David Best and his extraordinary temples, which are built during the Burning Man event and then incinerated on the Sunday. So we invited him and his community to come, and we recruited from both sides of the political and religious divide: young people, unemployed people, people who would never normally come across each other or speak to each other. And out of their extraordinary work rose a temple to rival the two cathedrals that exist in the town, one Catholic and one Protestant. But this was a temple to no religion, for everyone, for no community, but for everyone. And we put it in this place where everyone told me nobody would come. It was too dangerous. It sat between two communities. I just kept saying, "But it's got such a great view." (Laughter) And again, that same old question: Why wouldn't we do this? What you see in the picture is the beginning of 426 primary school children who were walked up the hill by the head teacher, who didn't want them to lose this opportunity. And just as happens in the Nevada desert, though in slightly different temperatures, the people of this community, 65,000 of them, turned out to write their grief, their pain, their hope, their hopes for the future, their love. Because in the end, this is only about love. They live in a post-conflict society: lots of post-traumatic stress, high suicide. And yet, for this brief moment — and it would be ridiculous to assume that it was more than that — somebody like Kevin — a Catholic whose father was shot when he was nine, upstairs in bed — Kevin came to work as a volunteer. And he was the first person to embrace the elderly Protestant lady who came through the door on the day we opened the temple to the public. It rose up. It sat there for five days. And then we chose — from our little tiny band of nonsectarian builders, who had given us their lives for this period of months to make this extraordinary thing — we chose from them the people who would incinerate it. And here you see the moment when, witnessed by 15,000 people who turned out on a dark, cold, March evening, the moment when they decided to put their enmity behind them, to inhabit this shared space, where everybody had an opportunity to say the things that had been unsayable, to say out loud, "You hurt me and my family, but I forgive you." And together, they watched as members of their community let go of this thing that was so beautiful, but was as hard to let go of as those thoughts and feelings that had gone into making it. (Music) Thank you. (Applause) |
What refugees need to start new lives | {0: 'Muhammed Idris wants to improve social services delivery through collective and artificial intelligence.'} | TED Residency | About two years ago, I got a phone call that changed my life. "Hey, this is your cousin Hassen." I froze. You see, I have well over 30 first cousins, but I didn't know anybody named Hassen. It turned out that Hassen was actually my mom's cousin and had just arrived in Montreal as a refugee. And over the next few months, I would have three more relatives coming to Canada to apply for asylum with little more than the clothes on their back. And in the two years since that phone call, my life has completely changed. I left academia and now lead a diverse team of technologists, researchers and refugees that is developing customized self-help resources for newcomers. We want to help them overcome language, cultural and other barriers that make them feel like they've lost control over their own lives. And we feel that AI can help restore the rights and the dignity that many people lose when seeking help. My family's refugee experience is not unique. According to the UNHCR, every minute, 20 people are newly displaced by climate change, economic crisis and social and political instability. And it was while volunteering at a local YMCA shelter that my cousin Hassen and other relatives were sent to that we saw and learned to appreciate how much effort and coordination resettlement requires. When you first arrive, you need to find a lawyer and fill out legal documents within two weeks. You also need to schedule a medical exam with a pre-authorized physician, just so that you can apply for a work permit. And you need to start looking for a place to live before you receive any sort of social assistance. With thousands fleeing the United States to seek asylum in Canada over the past few years, we quickly saw what it looks like when there are more people who need help than there are resources to help them. Social services doesn't scale quickly, and even if communities do their best to help more people with limited resources, newcomers end up spending more time waiting in limbo, not knowing where to turn. In Montreal, for example, despite millions of dollars being spent to support resettlement efforts, nearly 50 percent of newcomers still don't know that there are free resources that exist to help them with everything from filling out paperwork to finding a job. The challenge is not that this information doesn't exist. On the contrary, those in need are often bombarded with so much information that it's difficult to make sense of it all. "Don't give me more information, just tell me what to do," was a sentiment we heard over and over again. And it reflects how insanely difficult it could be to get your bearings when you first arrive in a new country. Hell, I struggled with the same issues when I got to Montreal, and I have a PhD. (Laughter) As another member of our team, himself also a refugee, put it: "In Canada, a SIM card is more important than food, because we will not die from hunger." But getting access to the right resources and information can be the difference between life and death. Let me say that again: getting access to the right resources and information can be the difference between life and death. In order to address these issues, we built Atar, the first-ever AI-powered virtual advocate that guides you step-by-step through your first week of arriving in a new city. Just tell Atar what you need help with. Atar will then ask you some basic questions to understand your unique circumstances and determine your eligibility for resources. For example: Do you have a place to stay tonight? If not, would you prefer an all-women's shelter? Do you have children? Atar will then generate a custom, step-by-step to-do list that tells you everything that you need to know, from where to go, how to get there, what to bring with you and what to expect. You can ask a question at any time, and if Atar doesn't have an answer, you'll be connected with a real person who does. But what's most exciting is that we help humanitarian and service organizations collect the data and the analytics that's necessary to understand the changing needs of newcomers in real time. That's a game changer. We've already partnered with the UNHCR to provide this technology in Canada, and in our work have conducted campaigns in Arabic, English, French, Creole and Spanish. When we talk about the issue of refugees, we often focus on the official statistic of 65.8 million forcibly displaced worldwide. But the reality is much greater than that. By 2050, there will be an additional 140 million people who are at risk of being displaced due to environmental degradation. And today — that is today — there are nearly one billion people who already live in illegal settlements and slums. Resettlement and integration is one of the greatest challenges of our time. and our hope is that Atar can provide every single newcomer an advocate. Our hope is that Atar can amplify existing efforts and alleviate pressure on a social safety net that's already stretched beyond imagination. But what's most important to us is that our work helps restore the rights and the dignity that refugees lose throughout resettlement and integration by giving them the resources that they need in order to help themselves. Thank you. (Applause) |
How to grow a glacier | null | TED-Ed | In the 13th Century, Genghis Khan embarked on a mission to take over Eurasia, swiftly conquering countries and drawing them into his expanding Mongol Empire. With his vast armies he became almost unstoppable. But, legend has it that there was one obstacle that even the impressive Khan couldn’t overcome: A towering wall of ice, grown by locals across a mountain pass to stop the Khan’s armies from invading their territory. No one knows how historically accurate that particular story is, but remarkably, it draws on fact: For centuries, in the Karakoram and Himalayan mountain ranges, people have been growing glaciers and using these homemade bodies of ice as sources of drinking water and irrigation for their crops. But before we get to that fascinating phenomenon, it’s important to understand the difference between glaciers that grow in the wild, and those that humans create. In the wild, glaciers require three conditions to grow: Snowfall, cold temperatures, and time. First, a great deal of snow falls and accumulates. Cold temperatures then ensure that the stacked up snow persists throughout the winter, spring, summer, and fall. Over the following years, decades, and centuries, the pressure of the accumulated snow transforms layers into highly compacted glacial ice. Artificially growing a glacier, however, is completely different. At the confluence of three great mountain ranges, the Himalayas, Karakoram, and Hindu Kush, some local cultures have believed for centuries that glaciers are alive. And what’s more, that certain glaciers can have different genders including male and female. Local Glacier Growers ‘breed’ new glaciers by grafting together—or marrying— fragments of ice from male and female glaciers, then covering them with charcoal, wheat husks, cloths, or willow branches so they can reproduce. Under their protective coverings, these glacierets transform into fully active glaciers that grow each year with additional snowfall. Those then serve as lasting reserves of water that farmers can use to irrigate their crops. These practices have spread to other cultures, where people are creating their own versions of glaciers and applying them to solve serious modern challenges around water supplies. Take Ladakh, a high-altitude desert region in northern India. It sits in the rain shadow of the Himalayas and receives on average fewer than ten centimeters of rain per year. As local glaciers shrink because of climate change, regional water scarcity is increasing. And so, local people have started growing their own glaciers as insurance against this uncertainty. These glaciers come in two types: horizontal, and vertical. Horizontal glaciers are formed when farmers redirect glacier meltwater into channels and pipes, then carefully siphon it off into a series of basins made from stones and earth. Villagers minutely control the release of water into these reservoirs, waiting for each new layer to freeze before filling the basin with another wave. In early spring, these frozen pools begin to melt, supplying villagers with irrigation for their fields. Local people make vertical glaciers using the meltwater from already-existing glaciers high above their villages. The meltwater enters channels that run downhill, flowing until it reaches a crop site where it bursts forth from a pipe pointing straight into the air. When winter temperatures dip, this water freezes as it arcs out of the pipe, ultimately forming a 50 meter ice sculpture called a stupa, shaped like an upside-down ice cream cone. This inverted form minimizes the amount of surface area it exposes to the sun in the spring and summer. That ensures that the mini-glacier melts slowly and provides a reliable supply of water to feed the farmers’ crops. These methods may be ancient, but they’re becoming more relevant as climate change takes its toll on our planet. In fact, people are now growing their own glaciers in many regions beyond Ladakh. Swiss people, utilizing modern glacier growing technology, created their first stupa in 2016 in the Swiss Alps. There are plans for over 100 more in villages in Pakistan, Kazakhstan, and Kyrgyzstan. Perhaps one day we’ll be able to harness our homegrown glaciers well enough to build whole walls of ice– this time not for keeping people out, but to enable life in some of the planet’s harshest landscapes. |
How do contraceptives work? | null | TED-Ed | Here's what has to happen for pregnancy to occur after sexual intercourse. Sperm must swim up the vagina, through the cervical opening, upwards through the uterus, and into one of the two fallopian tubes. If an egg, released during that month's ovulation, is in the tube, one sperm has a chance to fertilize it. Contraceptives are designed to prevent this process, and they work in three basic ways. They block the sperm, disable sperm before they reach the uterus, or suppress ovulation. Block is the simplest. Male and female condoms prevent sperm from coming into contact with the vaginal space. That barrier is also why they, unlike other contraceptive methods, are able to prevent transmission of certain sexually transmitted diseases. Meanwhile, the diaphragm, cervical cap, and sponge work by being placed over the cervix, barricading the entrance to the uterus. These contraceptives are sometimes called barrier methods and can be used with spermicides, an example of the second category, disable. A spermicide is a chemical that immobilizes and destroys sperm. Today's spermicides come as foam, cream, jelly, suppositories, and even a thin piece of translucent film that dissolves in the vagina. These products can be inserted directly into the vagina before intercourse, or can be combined with block methods, like a diaphragm or condom, for added proection. The third category for preventing pregnancy works by suppressing the action of an egg maturing in the ovary. If there isn't an egg available in the fallopian tube, there's nothing for sperm to fertilize. Hormonal contraceptives, including the pill, the patch, the Depo shot, and the vaginal ring all release synthetic versions of various combinations of progesterone and estrogen. This hormone cocktail suppresses ovulation, keeping the immature egg safely sequestered in the ovary. Synthetic progesterone also has a block trick up its sleeve. It makes cervical mucus too thick and sticky for sperm to swim through easily. There are other contraceptives that use multiple approaches at the same time. For example, many IUDs, or intrauterine devices, contain synthetic hormones which suppress ovulation. Some also contain copper, which disable sperm while also making egg implantation in the uterus difficult. Block, disable, or suppress: is one strategy better than the other? There are differences, but a lot of it has to do with how convenient and easy it is to use each contraceptive correctly. For example, male condoms would be about 98% effective if everyone used them perfectly. That 98% means if 100 couples correctly used condoms for a year, two women would get pregnant. But not everyone uses them correctly, so they're only 82% effective in practice. Other methods, like the patch and pill, are 99% effective when they're used perfectly. But in practice, that's 91%. Spermicide is only 85% effective, even with perfect usage, and just 71% effective with typical usage. Another important consideration in the choice of contraceptives are side effects, which almost exclusively affect women rather than men. Hormonal methods in particular can cause symptoms like headaches, nausea, and high blood pressure, but they vary from woman to woman. That's why these methods require a prescription from a doctor. The choice of contraceptive method is a personal one, and what works best for you now may change later. Scientists also continue to research new methods, such as a male pill that would prevent sperm production. In the meantime, there are quite a few options to block sperm, disable them, or suppress eggs and keep them out of reach. |
Should you trust your first impression? | null | TED-Ed | Imagine you're at a football game when this obnoxious guy sits next to you. He's loud, he spills his drink on you, and he makes fun of your team. Days later, you're walking in the park when suddenly it starts to pour rain. Who should show up at your side to offer you an umbrella? The same guy from the football game. Do you change your mind about him based on this second encounter, or do you go with your first impression and write him off? Research in social psychology suggests that we're quick to form lasting impressions of others based on their behaviors. We manage to do this with little effort, inferring stable character traits from a single behavior, like a harsh word or a clumsy step. Using our impressions as guides, we can accurately predict how people are going to behave in the future. Armed with the knowledge the guy from the football game was a jerk the first time you met him, you might expect more of the same down the road. If so, you might choose to avoid him the next time you see him. That said, we can change our impressions in light of new information. Behavioral researchers have identified consistent patterns that seem to guide this process of impression updating. On one hand, learning very negative, highly immoral information about someone typically has a stronger impact than learning very positive, highly moral information. So, unfortunately for our new friend from the football game, his bad behavior at the game might outweigh his good behavior at the park. Research suggests that this bias occurs because immoral behaviors are more diagnostic, or revealing, of a person's true character. Okay, so by this logic, bad is always stronger than good when it comes to updating. Well, not necessarily. Certain types of learning don't seem to lead to this sort of negativity bias. When learning about another person's abilities and competencies, for instance, this bias flips. It's actually the positive information that gets weighted more heavily. Let's go back to that football game. If a player scores a goal, it ultimately has a stronger impact on your impression of their skills than if they miss the net. The two sides of the updating story are ultimately quite consistent. Overall, behaviors that are perceived as being less frequent are also the ones that people tend to weigh more heavily when forming and updating impressions, highly immoral actions and highly competent actions. So, what's happening at the level of the brain when we're updating our impressions? Using fMRI, or functional Magnetic Resonance Imaging, researchers have identified an extended network of brain regions that respond to new information that's inconsistent with initial impressions. These include areas typically associated with social cognition, attention, and cognitive control. Moreover, when updating impressions based on people's behaviors, activity in the ventrolateral prefrontal cortex and the superior temporal sulcus correlates with perceptions of how frequently those behaviors occur in daily life. In other words, the brain seems to be tracking low-level, statistical properties of behavior in order to make complex decisions regarding other people's character. It needs to decide is this person's behavior typical or is it out of the ordinary? In the situation with the obnoxious-football-fan-turned-good-samaritan, your brain says, "Well, in my experience, pretty much anyone would lend someone their umbrella, but the way this guy acted at the football game, that was unusual." And so, you decide to go with your first impression. There's a good moral in this data: your brain, and by extension you, might care more about the very negative, immoral things another person has done compared to the very positive, moral things, but it's a direct result of the comparative rarity of those bad behaviors. We're more used to people being basically good, like taking time to help a stranger in need. In this context, bad might be stronger than good, but only because good is more plentiful. Think about the last time you judged someone based on their behavior, especially a time when you really feel like you changed your mind about someone. Was the behavior that caused you to update your impression something you'd expect anyone to do, or was it something totally out of the ordinary? |
How does your smartphone know your location? | null | TED-Ed | How does your smartphone know exactly where you are? The answer lies 12,000 miles over your head in an orbiting satellite that keeps time to the beat of an atomic clock powered by quantum mechanics. Phew. Let's break that down. First of all, why is it so important to know what time it is on a satellite when location is what we're concerned about? The first thing your phone needs to determine is how far it is from a satellite. Each satellite constantly broadcasts radio signals that travel from space to your phone at the speed of light. Your phone records the signal arrival time and uses it to calculate the distance to the satellite using the simple formula, distance = c x time, where c is the speed of light and time is how long the signal traveled. But there's a problem. Light is incredibly fast. If we were only able to calculate time to the nearest second, every location on Earth, and far beyond, would seem to be the same distance from the satellite. So in order to calculate that distance to within a few dozen feet, we need the best clock ever invented. Enter atomic clocks, some of which are so precise that they would not gain or lose a second even if they ran for the next 300 million years. Atomic clocks work because of quantum physics. All clocks must have a constant frequency. In other words, a clock must carry out some repetitive action to mark off equivalent increments of time. Just as a grandfather clock relies on the constant swinging back and forth of a pendulum under gravity, the tick tock of an atomic clock is maintained by the transition between two energy levels of an atom. This is where quantum physics comes into play. Quantum mechanics says that atoms carry energy, but they can't take on just any arbitrary amount. Instead, atomic energy is constrained to a precise set of levels. We call these quanta. As a simple analogy, think about driving a car onto a freeway. As you increase your speed, you would normally continuously go from, say, 20 miles/hour up to 70 miles/hour. Now, if you had a quantum atomic car, you wouldn't accelerate in a linear fashion. Instead, you would instantaneously jump, or transition, from one speed to the next. For an atom, when a transition occurs from one energy level to another, quantum mechanics says that the energy difference is equal to a characteristic frequency, multiplied by a constant, where the change in energy is equal to a number, called Planck's constant, times the frequency. That characteristic frequency is what we need to make our clock. GPS satellites rely on cesium and rubidium atoms as frequency standards. In the case of cesium 133, the characteristic clock frequency is 9,192,631,770 Hz. That's 9 billion cycles per second. That's a really fast clock. No matter how skilled a clockmaker may be, every pendulum, wind-up mechanism and quartz crystal resonates at a slightly different frequency. However, every cesium 133 atom in the universe oscillates at the same exact frequency. So thanks to the atomic clock, we get a time reading accurate to within 1 billionth of a second, and a very precise measurement of the distance from that satellite. Let's ignore the fact that you're almost definitely on Earth. We now know that you're at a fixed distance from the satellite. In other words, you're somewhere on the surface of a sphere centered around the satellite. Measure your distance from a second satellite and you get another overlapping sphere. Keep doing that, and with just four measurements, and a little correction using Einstein's theory of relativity, you can pinpoint your location to exactly one point in space. So that's all it takes: a multibillion-dollar network of satellites, oscillating cesium atoms, quantum mechanics, relativity, a smartphone, and you. No problem. |
The evolution of animal genitalia | null | TED-Ed | The evolutionary tango of animal genitalia. Can you guess what you're looking at? If you answered "duck vagina," you'd be right. Although the bird's outward appearance may not strike you as especially odd, it uses this strange, intricate, cork-screw shaped contraption to reproduce. We see similarly unbelievable genitalia in insects, mammals, reptiles, fish, spiders, and even snails. Apparently, no organs evolve faster and into more variable shapes than those involved in procreation. Superficially, it makes sense because evolution works via reproduction. When an animal leaves more offspring, its genes will spread. And since genitalia are an animal's tools for reproduction, any improvement there will have immediate effect. And yet, what's the point of having such decorative nether regions? After all, the function of genitalia seems simple. A penis deposits a bit of sperm and a vagina receives it and delivers it to the egg. A pipette-like thingy on the male and a funnel-like gizmo on the female should do just fine for any animal. And yet, that's not what we see. The penis of a chicken flea, for example, looks nothing like a pipette, more like an exploded grandfather clock. And the vagina of a featherwing beetle resembles something you'd find in a Dr. Seuss book. Throughout the animal kingdom, genitalia are very complex things, much more complicated than seems necessary for what they're meant to do. That's because genitalia do more than just deposit and receive sperm. Many male animals also use the penis as courtship device, like crane flies. In some South American species, males have a tiny washboard and scraper on their penis, which produces a song that reverberates throughout the female's body when they mate. It's thought that if female crane flies enjoy this unusual serenade, they'll allow the male to father their offspring. This way, the genes of the most musical penises spread, leading to rapid evolution of insects' phalluses. Similarly, some beetles have two little drumsticks on either side of the penis. During mating, they'll rub, slap, or tap the female with these. And some hoofed mammals, like rams and bulls, use a whip-like extension on the penis's left side to create a sensation during mating. But how can females really choose between males if she can only assess them after mating? This is where the power of female adaptation comes into play. In fact, insemination is different to conception, and the female genitalia exploit this distinction. For instance, in some dung flies, the vagina contains pockets for separating sperm from different males depending on how appealing they were. Males using their penises for courtship and females controlling their own sperm management are two reasons why genitalia evolve into such complex shapes. But there are others because genitalia are also where a sexual conflict is played out. A female's interests are best served if she fertilizes her eggs with the sperm of the best fathers and creates genetic variability amongst her offspring. For a male, on the other hand, this is bad news. For him, it would be best if a female used his sperm to fertilize all of her eggs. So we see cycles of adaptation in an evolutionary arms race to retain control. Black widow spiders have a disposable penis tip that breaks off inside the vagina blocking the attempts of his rivals, and bed bug males bypass a female's genitalia altogether using a syringe-like penis to inject sperm cells directly into her belly. Not to be outdone, females have evolved their own countermeasures. In some bed bug species, the females have evolved an entirely new set of genitalia on their right hand flanks where the males usually pierce them. That allows them to maintain the power to filter out unwanted sperm with their genitalia. And duck vaginas are shaped like a clockwise spiral so that when the male inflates his long, counterclockwise coiled penis into her, and she disapproves, all she needs to do is flex her vaginal muscles and the penis just flubs out. So, genitalia differs so much, not just to fascinate us, but because in every species, they're the result of a furious evolutionary tango of sex that has been going on for millions of years and will continue for millions of years to come. |
Why we need more dogs in hospitals | {0: 'ファシリティドッグ・ハンドラー\r\n\r\n静岡県函南町生まれ。静岡県立大学看護学部看護学科卒業。国立成育医療研究センターを経て、2009年認定 特定非営利活動法人シャイン・オン・キッズに就職。2010年から2年間、静岡県立こども病院においてファシリティドッグ・ハンドラーとして活動。2012年より神奈川県立こども医療センターで活動中。\r\n\r\n森田優子さん＆ベイリーが所属する認定特定非営利活動法人シャイン・オン・キッズ\r\nWebサイトhttp://sokids.org/ja/', 1: 'ベイリー（ゴールデンレトリバー）\r\nファシリティドッグ\r\n\r\n2007年12月14日オーストラリアで生まれ。Assistance Dogs of Hawaii でファシリティドッグとしてのトレーニングを受ける。2歳前に卒業し、2009年11月静岡へ。以後ハンドラーの森田優子さんと共に活動中。'} | TEDxShimizu | (Directing Bailey in English) Hello, everyone. My name is Yuko Morita. This is a facility dog, Bailey. When you were a kid, were you afraid of getting shots? When you were getting a flu shot at school, you probably asked your friends, 'Did it hurt? Did it hurt?' As you know, kids are very afraid of injections or having their blood drawn. Hospitalised children have to have their blood drawn so many times. Some kids need bone-marrow aspirations by drilling a thick needle into their spine. This dog, Bailey has the magical power to make these kids say: 'If Bailey is with me, I would put up with it 100 more times'. He is such a competent dog. The Japanese medical level is said to be top-notch, for curing diseases. But in Japan, while 'to be patient' has been considered a virtue, it is said that the quality of hospitalised life is poorly supported. I used to work as a registered nurse at a children's hospital in Tokyo. One day a mother of a hospitalised kid said, 'This is almost like being in jail'. I was thinking that I was working very hard for the children, and I was very shocked to hear that. In fact, kids in the hospital are not supposed to go out even for a walk. They are not allowed to have their favourite foods. They barely have fun. Some kids stop smiling. When I think back about it, it might as well be called a jail. At that time, I was with an NPO called 'Shine On! Kids' and they offered to let me become a handler of a service dog. The Non-Profit Organisation was founded to emotionally support kids and their families who are suffering from childhood cancer and other incurable diseases. At that time, I only knew that a dog is taken to a children's hospital and the dog works as a member of the medical staff — there were a number of facility dogs working in Europe and the US, yet obiously none in Japan; that was all I knew about facility dogs. I thought 'If a service dog were working in this ward, the children's hospital life, once called a jail, would be way happier', and I was excited to think so. Without hesitation I said, 'Yes, I would love to'. There is no training institutions for facility dog program in Japan. Both Bailey and I were trained at a Hawaiian training centre. In a children's hospital in Hawaii, we also practiced following around our senior facility dog and their handler. To my surprise, the service dog went into the ICU. The intensive-care unit is where seriously ill patients are taken care of. There was a child who had just gotten out of surgery with their head half-shaven, and a large scar on their head. The kid was frowing painfully. To my great concern, 'Is it really OK to go there in such a serious situation?' the facility dog went in there, and climbed on the bed right beside the kid laying with the tubes around them, and went to sleep alongside the kid. Then the kid grew relaxed. In spite of all the pain of moving, the kid hugged the dog and closed their eyes. The kid looked so calm and easy. At the sight of it, I thought ’WOW, that's cool!’ Being excited about making all the hospital wards full of smiles, I came back to Japan with Bailey. However, facility dogs are totally unprecedented in Japan. The Western mindset for dogs is totally different from that of Japan. In Europe and the US, it's been quite normal to have dogs in the house as family members. On the other hand, in Japan, we have a history of having them outside. It is outrageous to have a dog inside the hospital ward: that was what Japanese hospitals thought. Before us, sometimes there were dogs volunteered to visit hospitals in Japan. But there was not a precedent of having a dog in hospital everyday, and considering dogs as a medical staff. What was right in Hawaii was far from right in Japan. We desperately looked for a hospital that could accept Bailey as a staff. Then eventually we were accepted by the Shizuoka Children's Hospital. But the reality was that people said; 'Can't the dog be replaced with a dog robot?' or 'To protect kids against infections, do not enter this ward'. At first we could enter only one ward. So one-day of rounds was finished in a few minutes. We got to the workplace and an hour later, it was time to go home. 'I don't think Japanese culture is going to make people want to adopt a facility dog programme', I could only think in a negative way. But in fact, children needed Bailey. Five years have passed, and now we are accepted by almost all wards. Bailey brings about positive differences to both kids and their families', — that was what doctors and nurses started to notice. There was a child who was visually impaired and was always screaming in panic when they had their blood collected. But with Bailey by their side, they were distracted by petting Bailey on the head, the kid could go through blood tests without crying. Another kid who wouldn’t move at all due to pain after surgery suddenly got up just because they wanted to see Bailey. That was a big surprise to the doctor. A family, who are suddenly told that their child has cancer, will pretend as if nothing happening to prevent their kid from being nervous. But people cannot suppress their feelings for good. Sometimes it is important to cry. With somebody who is human, they would feel a need 'to say something'. But to Bailey, they never have to say anything if they do not want to. I saw a mother in a hospital corridor, after hugging Bailey, crying as she wanted and with a relaxed expression, she went back to her kid's bed. Bailey was a positive influence for their families, too. Then I found there are three important bonds for a facility dog. One is a bond between Bailey and the kids, another is Bailey and his handler, and the other is Bailey and the medical staff. These are three important bonds with Bailey. The first bond is: as Bailey works at the same hospital everyday, he sees the same children many times. For children, just having a dog is not good enough. Bailey, who comes to them everyday, really matters. Only with Bailey who has bonds with the kids, can they be courageous enough to hang in there. Even with a dog phobia, almost all kids will come to like Bailey eventually. For kids, Bailey is a teammate with a tail who fight against their illness. Bailey can even enter the surgical theatre with a child. Even an adult is scared of getting an operation, right? Wondering 'Does it hurt?', or feeling scared, they have to spend the terrifying time from the ward to the theatre. But holding Bailey's leash, walking with him, children can guide Bailey smiling and walking to the theatre. It is a privilege walk with everyone's favourite Bailey, without anyone else! Some kids walk playfully around Bailey's fluffy tail as if they are cats. Some kids say smiling, 'Bailey's wagging his tail means Good Luck'. In this way, scary feelings turn to exciting feelings; which encourages kids to go to the theatre. The second bond is: between a facility dog and their hander, who live together twenty-four seven. We always spend holidays together too. This is very important; just getting together while working and saying 'Bye-Bye' after five doesn't make any sense. We sleep at night and Bailey sleeps with his head on my arm. The bond between a facility dog and their handler is the basis on which a facility dog works professionally. Only the bond with me can convince Bailey to trust me to work together. But the truth is; you may think that a training dog will do anything I say, Bailey is a stubborn guy who goes only where he wants. To a direction he doesn't to want to go, he does like this. Can you see he is hanging on with all his might? Planting his feet firmly on the ground, digging his nails into it, he never goes where he doesn't want to. While walking on the street, I sometimes struggle with Bailey sitting there. People passing by always say laughing, 'That's troublesome'. But he has never refused to go to the hospital. On the contrary, he sometimes refuses to go home, squatting there, going back into the hospital ward. Dogs easily understand what people are thinking about them. Because there are many people who love him, Bailey loves the hospital very much. Both a dog and people are mutually affected; that is where the facility dog belongs. This is why non-sentient toy dogs cannot make this happen. A robot dog can not make this happen. The third bond is between Bailey and the medical staff. The handler of a facility dog is a medical staff. The reason why only medical staff can be a handler of a facility dog is: that a facility dog's work includes not only healing mentally, but also curing physically. Bailey and I sometimes take a part in the conversations where treatment courses of patients are decided. I also figure out how our patient kids are and work out how to approach this patient. I also write on the medical charts. In this way, to be involved with specific purpose is what only facility dogs are capable of, and why a handler of a facility dog must be certified medical staff. It has been five years since Bailey and I started working in Japan. We have met thousands of children. We once met a kid in the terminal phase of disease and the kid could not eat. He wanted to but he couldn't eat; that was his situation. Given a short span of time, both his family and nurses wished that he could enjoy whatever little amount of food he could. Then there was a suggestion made Bailey attended at his dinner table. With Bailey, the kid was happy to sit up smiling. Saying, 'Bailey, look at me', though it was only a few mouthful, but he could managed to grab spaghetti into his mouth. He could also enjoy ice cream, not being forced to do so, but willingly to do so. Only the presence of Bailey bedside could make that level of change. The bad impression of a hospital changed so much as to make children say, 'I want to be hospitalised to see Bailey'. With Bailey, kids can double their fun. With Bailey, kids can share tears and fears. Most children are discharged from hospital safe and sound. But sadly, some kids have to leave this world forever, and Bailey sometimes sleeps with them till just before their last moments. We say 'You know, Bailey's with you', 'It's warm, isn't?' to kids. The time goes on sadly but warmly. We sometimes attend a funeral for children. When parents have to close the lid of their own child's coffin, can you imagine how they feel? In fact every family says 'We were really happy to have Bailey with us'. They always say that. 'Before Bailey, the hospital stay had been just so heart-wrenching'. 'With Bailey our kid's life changed so much'. These are what bereaved families said to us. A family who lost their child will reflect on their child everyday, through their long span of life. Remembering their child as 'a poor soul who went through so many painful operations; or remembering their child as 'a laughing kid sleeping with Bailey just before death; their feelings are completely different, aren't they? We wish to make a small portion of happiness in their heartbreaking memory. We wish the bereaved family remember as many smiles of their kid as possible. The Facility Dog Programme is not an option, but necessity for hospital care, that's what I strongly feel about it. Japan's medical care is said to be the highest in the world. Not just curing disease, but also having an environment for healing disease more proactively is necessary, I think. For patients, they can't have too much fun. There are a lot of facility dogs in Europe and the US, but in Japan we have only two. I would like to have facility dogs as a standard in Japanese hospitals and make Japanese hospitals a fun place to be in, even for patients who have medical conditions. So many children who passed away are watching for us from heaven. For those kids, I would like to make the Japanese medical front a place where I can be proud to say, 'Hey, it's a good hospital, isn't it?' (Applause) |
An AI smartwatch that detects seizures | {0: 'MIT Professor Rosalind Picard invents technologies that help people better understand emotion and behaviors that impact human health. '} | TEDxBeaconStreet | This is Henry, a cute boy, and when Henry was three, his mom found him having some febrile seizures. Febrile seizures are seizures that occur when you also have a fever, and the doctor said, "Don't worry too much. Kids usually outgrow these." When he was four, he had a convulsive seizure, the kind that you lose consciousness and shake — a generalized tonic-clonic seizure — and while the diagnosis of epilepsy was in the mail, Henry's mom went to get him out of bed one morning, and as she went in his room, she found his cold, lifeless body. Henry died of SUDEP, sudden unexpected death in epilepsy. I'm curious how many of you have heard of SUDEP. This is a very well-educated audience, and I see only a few hands. SUDEP is when an otherwise healthy person with epilepsy dies and they can't attribute it to anything they can find in an autopsy. There is a SUDEP every seven to nine minutes. That's on average two per TED Talk. Now, a normal brain has electrical activity. You can see some of the electrical waves coming out of this picture of a brain here. And these should look like typical electrical activity that an EEG could read on the surface. When you have a seizure, it's a bit of unusual electrical activity, and it can be focal. It can take place in just a small part of your brain. When that happens, you might have a strange sensation. Several could be happening here in the audience right now, and the person next to you might not even know. However, if you have a seizure where that little brush fire spreads like a forest fire over the brain, then it generalizes, and that generalized seizure takes your consciousness away and causes you to convulse. There are more SUDEPs in the United States every year than sudden infant death syndrome. Now, how many of you have heard of sudden infant death syndrome? Right? Pretty much every hand goes up. So what's going on here? Why is this so much more common and yet people haven't heard of it? And what can you do to prevent it? Well, there are two things, scientifically shown, that prevent or reduce the risk of SUDEP. The first is: "Follow your doctor's instructions, take your medications." Two-thirds of people who have epilepsy get it under control with their medications. The second thing that reduces the risk of SUDEP is companionship. It's having somebody there at the time that you have a seizure. Now, SUDEP, even though most of you have never heard of it, is actually the number two cause of years of potential life lost of all neurological disorders. The vertical axis is the number of deaths times the remaining life span, so higher is much worse impact. SUDEP, however, unlike these others, is something that people right here could do something to push that down. Now, what is Roz Picard, an AI researcher, doing here telling you about SUDEP, right? I'm not a neurologist. When I was working at the Media Lab on measurement of emotion, trying to make our machines more intelligent about our emotions, we started doing a lot of work measuring stress. We built lots of sensors that measured it in lots of different ways. But one of them in particular grew out of some of this very old work with measuring sweaty palms with an electrical signal. This is a signal of skin conductance that's known to go up when you get nervous, but it turns out it also goes up with a lot of other interesting conditions. But measuring it with wires on your hand is really inconvenient. So we invented a bunch of other ways of doing this at the MIT Media Lab. And with these wearables, we started to collect the first-ever clinical quality data 24-7. Here's a picture of what that looked like the first time an MIT student collected skin conductance on the wrist 24-7. Let's zoom in a little bit here. What you see is 24 hours from left to right, and here is two days of data. And first, what surprised us was sleep was the biggest peak of the day. Now, that sounds broken, right? You're calm when you're asleep, so what's going on here? Well, it turns out that our physiology during sleep is very different than our physiology during wake, and while there's still a bit of a mystery why these peaks are usually the biggest of the day during sleep, we now believe they're related to memory consolidation and memory formation during sleep. We also saw things that were exactly what we expected. When an MIT student is working hard in the lab or on homeworks, there is not only emotional stress, but there's cognitive load, and it turns out that cognitive load, cognitive effort, mental engagement, excitement about learning something — those things also make the signal go up. Unfortunately, to the embarrassment of we MIT professors, (Laughter) the low point every day is classroom activity. Now, I am just showing you one person's data here, but this, unfortunately, is true in general. This sweatband has inside it a homebuilt skin-conductance sensor, and one day, one of our undergrads knocked on my door right at the end of the December semester, and he said, "Professor Picard, can I please borrow one of your wristband sensors? My little brother has autism, he can't talk, and I want to see what's stressing him out." And I said, "Sure, in fact, don't just take one, take two," because they broke easily back then. So he took them home, he put them on his little brother. Now, I was back in MIT, looking at the data on my laptop, and the first day, I thought, "Hmm, that's odd, he put them on both wrists instead of waiting for one to break. OK, fine, don't follow my instructions." I'm glad he didn't. Second day — chill. Looked like classroom activity. (Laughter) A few more days ahead. The next day, one wrist signal was flat and the other had the biggest peak I've ever seen, and I thought, "What's going on? We've stressed people out at MIT every way imaginable. I've never seen a peak this big." And it was only on one side. How can you be stressed on one side of your body and not the other? So I thought one or both sensors must be broken. Now, I'm an electroengineer by training, so I started a whole bunch of stuff to try to debug this, and long story short, I could not reproduce this. So I resorted to old-fashioned debugging. I called the student at home on vacation. "Hi, how's your little brother? How's your Christmas? Hey, do you have any idea what happened to him?" And I gave this particular date and time, and the data. And he said, "I don't know, I'll check the diary." Diary? An MIT student keeps a diary? So I waited and he came back. He had the exact date and time, and he says, "That was right before he had a grand mal seizure." Now, at the time, I didn't know anything about epilepsy, and did a bunch of research, realized that another student's dad is chief of neurosurgery at Children's Hospital Boston, screwed up my courage and called Dr. Joe Madsen. "Hi, Dr. Madsen, my name's Rosalind Picard. Is it possible somebody could have a huge sympathetic nervous system surge" — that's what drives the skin conductance — "20 minutes before a seizure?" And he says, "Probably not." He says, "It's interesting. We've had people whose hair stands on end on one arm 20 minutes before a seizure." And I'm like, "On one arm?" I didn't want to tell him that, initially, because I thought this was too ridiculous. He explained how this could happen in the brain, and he got interested. I showed him the data. We made a whole bunch more devices, got them safety certified. 90 families were being enrolled in a study, all with children who were going to be monitored 24-7 with gold-standard EEG on their scalp for reading the brain activity, video to watch the behavior, electrocardiogram — ECG — and now EDA, electrodermal activity, to see if there was something in this periphery that we could easily pick up, related to a seizure. We found, in 100 percent of the first batch of grand mal seizures, this whopper of responses in the skin conductance. The blue in the middle, the boy's sleep, is usually the biggest peak of the day. These three seizures you see here are popping out of the forest like redwood trees. Furthermore, when you couple the skin conductance at the top with the movement from the wrist and you get lots of data and train machine learning and AI on it, you can build an automated AI that detects these patterns much better than just a shake detector can do. So we realized that we needed to get this out, and with the PhD work of Ming-Zher Poh and later great improvements by Empatica, this has made progress and the seizure detection is much more accurate. But we also learned some other things about SUDEP during this. One thing we learned is that SUDEP, while it's rare after a generalized tonic-clonic seizure, that's when it's most likely to happen — after that type. And when it happens, it doesn't happen during the seizure, and it doesn't usually happen immediately afterwards, but immediately afterwards, when the person just seems very still and quiet, they may go into another phase, where the breathing stops, and then after the breathing stops, later the heart stops. So there's some time to get somebody there. We also learned that there is a region deep in the brain called the amygdala, which we had been studying in our emotion research a lot. We have two amygdalas, and if you stimulate the right one, you get a big right skin conductance response. Now, you have to sign up right now for a craniotomy to get this done, not exactly something we're going to volunteer to do, but it causes a big right skin conductance response. Stimulate the left one, big left skin conductance response on the palm. And furthermore, when somebody stimulates your amygdala while you're sitting there and you might just be working, you don't show any signs of distress, but you stop breathing, and you don't start again until somebody stimulates you. "Hey, Roz, are you there?" And you open your mouth to talk. As you take that breath to speak, you start breathing again. So we had started with work on stress, which had enabled us to build lots of sensors that were gathering high quality enough data that we could leave the lab and start to get this in the wild; accidentally found a whopper of a response with the seizure, neurological activation that can cause a much bigger response than traditional stressors; lots of partnership with hospitals and an epilepsy monitoring unit, especially Children's Hospital Boston and the Brigham; and machine learning and AI on top of this to take and collect lots more data in service of trying to understand these events and if we could prevent SUDEP. This is now commercialized by Empatica, a start-up that I had the privilege to cofound, and the team there has done an amazing job improving the technology to make a very beautiful sensor that not only tells time and does steps and sleep and all that good stuff, but this is running real-time AI and machine learning to detect generalized tonic-clonic seizures and send an alert for help if I were to have a seizure and lose consciousness. This just got FDA-approved as the first smartwatch to get approved in neurology. (Applause) Now, the next slide is what made my skin conductance go up. One morning, I'm checking my email and I see a story from a mom who said she was in the shower, and her phone was on the counter by the shower, and it said her daughter might need her help. So she interrupts her shower and goes running to her daughter's bedroom, and she finds her daughter facedown in bed, blue and not breathing. She flips her over — human stimulation — and her daughter takes a breath, and another breath, and her daughter turns pink and is fine. I think I turned white reading this email. My first response is, "Oh no, it's not perfect. The Bluetooth could break, the battery could die. All these things could go wrong. Don't rely on this." And she said, "It's OK. I know no technology is perfect. None of us can always be there all the time. But this, this device plus AI enabled me to get there in time to save my daughter's life." Now, I've been mentioning children, but SUDEP peaks, actually, among people in their 20s, 30s and 40s, and the next line I'm going to put up is probably going to make some people uncomfortable, but it's less uncomfortable than we'll all be if this list is extended to somebody you know. Could this happen to somebody you know? And the reason I bring up this uncomfortable question is because one in 26 of you will have epilepsy at some point, and from what I've been learning, people with epilepsy often don't tell their friends and their neighbors that they have it. So if you're willing to let them use an AI or whatever to summon you in a moment of possible need, if you would let them know that, you could make a difference in their life. Why do all this hard work to build AIs? A couple of reasons here: one is Natasha, the girl who lived, and her family wanted me to tell you her name. Another is her family and the wonderful people out there who want to be there to support people who have conditions that they've felt uncomfortable in the past mentioning to others. And the other reason is all of you, because we have the opportunity to shape the future of AI. We can actually change it, because we are the ones building it. So let's build AI that makes everybody's lives better. Thank you. (Applause) |
What on Earth is spin? | null | TED-Ed | The next time you see a news report of a hurricane or a tropical storm showing high winds battering trees and houses, ask yourself, "How did the wind get going so fast?" Amazingly enough, this is a motion that started more than five billion years ago. But, to understand why, we need to understand spin. In physics, we talk about two types of motion. The first is straight-line motion. You push on something, and it moves forward. The second type, spin, involves an object rotating, or turning on its axis in place. An object in straight-line motion will move forever unless something, like the friction of the ground beneath it, causes it to slow down and stop. The same thing happens when you get something spinning. It will keep on spinning until something stops it. But the spin can speed up. If an ice skater is gliding across the ice in straight-line motion and she pulls her arms in, she keeps on gliding at the same speed. But if she is spinning on the ice and she pulls her arms in, you know what happens next. She spins faster. This is called the conservation of angular momentum. Mathematically, angular momentum is a product of two numbers, one that gives the spin rate and one that gives the distance of the mass from the axis. If something is freely spinning, as one number gets bigger, the other gets smaller. Arms closer, spin faster. Arms farther, spin slower. Spin causes other effects, too. If you are riding on a spinning merry-go-round and you toss a ball to a friend, it will appear to follow a curving path. It doesn't actually curve, though. It really goes in a straight line. You were the one who was following a curving path, but, from your point of view, the ball appears to curve. We call this the coriolis effect. Oh, and you are riding on a speeding merry-go-round right now at this very moment. We call it the Earth. The Earth spins on its axis once each day. But why does the Earth spin? Now, that's a story that starts billions of years ago. A cloud of dust and gas that form the Sun and the Earth and the planets and you and me started to collapse as gravity pulled it all together. Before it started to collapse, this cloud had a very gentle spin. And, as it collapsed, like that ice skater pulling her arms in, the spin got faster and faster. And everything that formed out of the cloud, the Sun and the planets around the Sun and the moons around the planets, all inherited this spin. And this inherited spin is what gives us night and day. And this day-night cycle is what drives our weather. The Earth is warm on the daytime side, cool on the nighttime side, and it's warmer at the equator than at the poles. The differences in temperature make differences in air pressure, and the differences in air pressure make air move. They make the wind blow. But, because the Earth spins, the moving air curves to the right in the Northern Hemisphere because of the coriolis effect. If there's a region of low pressure in the atmosphere, air is pushed toward it, like water going down a drain. But the air curves to the right as it goes, and this gives it a spin. With the dramatic low pressure in a storm, the air gets pulled in tighter and tighter, so it gets going faster and faster, and this is how we get the high winds of a hurricane. So, when you see a spinning storm on a weather report, think about this: The spin ultimately came from the spin of the Earth, and the Earth's spin is a remnant, a fossil relic, of the gentle spin of the cloud of dust and gas that collapsed to make the Earth some five billion years ago. You are watching something, the spin, that is older than dirt, that's older than rocks, that's older than the Earth itself. |
Who am I? A philosophical inquiry | null | TED-Ed | Throughout the history of mankind, three little words have sent poets to the blank page, philosophers to the Agora, and seekers to the oracles: "Who am I?" From the ancient Greek aphorism inscribed on the Temple of Apollo, "Know thyself," to The Who's rock anthem, "Who Are You?" philosophers, psychologists, academics, scientists, artists, theologians and politicians have all tackled the subject of identity. Their hypotheses are widely varied and lack significant consensus. These are smart, creative people, so what's so hard about coming up with the right answer? One challenge certainly lies with the complex concept of the persistence of identity. Which you is who? The person you are today? Five years ago? Who you'll be in 50 years? And when is "am"? This week? Today? This hour? This second? And which aspect of you is "I"? Are you your physical body? Your thoughts and feelings? Your actions? These murky waters of abstract logic are tricky to navigate, and so it's probably fitting that to demonstrate the complexity, the Greek historian Plutarch used the story of a ship. How are you "I"? As the tale goes, Theseus, the mythical founder King of Athens, single-handedly slayed the evil Minotaur at Crete, then returned home on a ship. To honor this heroic feat, for 1000 years Athenians painstakingly maintained his ship in the harbor, and annually reenacted his voyage. Whenever a part of the ship was worn or damaged, it was replaced with an identical piece of the same material until, at some point, no original parts remained. Plutarch noted the Ship of Theseus was an example of the philosophical paradox revolving around the persistence of identity. How can every single part of something be replaced, yet it still remains the same thing? Let's imagine there are two ships: the ship that Theseus docked in Athens, Ship A, and the ship sailed by the Athenians 1000 years later, Ship B. Very simply, our question is this: does A equal B? Some would say that for 1000 years there has been only one Ship of Theseus, and because the changes made to it happened gradually, it never at any point in time stopped being the legendary ship. Though they have absolutely no parts in common, the two ships are numerically identical, meaning one and the same, so A equals B. However, others could argue that Theseus never set foot on Ship B, and his presence on the ship is an essential qualitative property of the Ship of Theseus. It cannot survive without him. So, though the two ships are numerically identical, they are not qualitatively identical. Thus, A does not equal B. But what happens when we consider this twist? What if, as each piece of the original ship was cast off, somebody collected them all, and rebuilt the entire original ship? When it was finished, undeniably two physical ships would exist: the one that's docked in Athens, and the one in some guy's backyard. Each could lay claim to the title, "The Ship of Theseus," but only would could actually be the real thing. So which one is it, and more importantly, what does this have to do with you? Like the Ship of Theseus, you are a collection of constantly changing parts: your physical body, mind, emotions, circumstances, and even your quirks, always changing, but still in an amazing and sometimes illogical way, you stay the same, too. This is one of the reasons that the question, "Who am I?" is so complex. And in order to answer it, like so many great minds before you, you must be willing to dive into the bottomless ocean of philosophical paradox. Or maybe you could just answer, "I am a legendary hero sailing a powerful ship on an epic journey." That could work, too. |
The genius of Marie Curie | {0: 'Shohini Ghose explores the strange quantum world of atoms and photons to understand the fundamental laws of the universe and harness them for quantum computing and communication -- and works to make science accessible and inclusive for people of all genders and backgrounds.'} | TED-Ed | If you want a glimpse of Marie Curie's manuscripts, you'll have to sign a waiver and put on protective gear to shield yourself from radiation contamination. Madame Curie's remains, too, were interred in a lead-lined coffin, keeping the radiation that was the heart of her research, and likely the cause of her death, well contained. Growing up in Warsaw in Russian-occupied Poland, the young Marie, originally named Maria Sklodowska, was a brilliant student, but she faced some challenging barriers. As a woman, she was barred from pursuing higher education, so in an act of defiance, Marie enrolled in the Floating University, a secret institution that provided clandestine education to Polish youth. By saving money and working as a governess and tutor, she eventually was able to move to Paris to study at the reputed Sorbonne. There, Marie earned both a physics and mathematics degree surviving largely on bread and tea, and sometimes fainting from near starvation. In Paris, Marie met the physicist Pierre Curie, who shared his lab and his heart with her. But she longed to be back in Poland. Upon her return to Warsaw, though, she found that securing an academic position as a woman remained a challenge. All was not lost. Back in Paris, the lovelorn Pierre was waiting, and the pair quickly married and became a formidable scientific team. Another physicist's work sparked Marie Curie's interest. In 1896, Henri Becquerel discovered that uranium spontaneously emitted a mysterious X-ray-like radiation that could interact with photographic film. Curie soon found that the element thorium emitted similar radiation. Most importantly, the strength of the radiation depended solely on the element's quantity, and was not affected by physical or chemical changes. This led her to conclude that radiation was coming from something fundamental within the atoms of each element. The idea was radical and helped to disprove the long-standing model of atoms as indivisible objects. Next, by focusing on a super radioactive ore called pitchblende, the Curies realized that uranium alone couldn't be creating all the radiation. So, were there other radioactive elements that might be responsible? In 1898, they reported two new elements, polonium, named for Marie's native Poland, and radium, the Latin word for ray. They also coined the term radioactivity along the way. By 1902, the Curies had extracted a tenth of a gram of pure radium chloride salt from several tons of pitchblende, an incredible feat at the time. Later that year, Pierre Curie and Henri Becquerel were nominated for the Nobel Prize in physics, but Marie was overlooked. Pierre took a stand in support of his wife's well-earned recognition. And so both of the Curies and Becquerel shared the 1903 Nobel Prize, making Marie Curie the first female Nobel Laureate. Well funded and well respected, the Curies were on a roll. But tragedy struck in 1906 when Pierre was crushed by a horse-drawn cart as he crossed a busy intersection. Marie, devastated, immersed herself in her research and took over Pierre's teaching position at the Sorbonne, becoming the school's first female professor. Her solo work was fruitful. In 1911, she won yet another Nobel, this time in chemistry for her earlier discovery of radium and polonium, and her extraction and analysis of pure radium and its compounds. This made her the first, and to this date, only person to win Nobel Prizes in two different sciences. Professor Curie put her discoveries to work, changing the landscape of medical research and treatments. She opened mobile radiology units during World War I, and investigated radiation's effects on tumors. However, these benefits to humanity may have come at a high personal cost. Curie died in 1934 of a bone marrow disease, which many today think was caused by her radiation exposure. Marie Curie's revolutionary research laid the groundwork for our understanding of physics and chemistry, blazing trails in oncology, technology, medicine, and nuclear physics, to name a few. For good or ill, her discoveries in radiation launched a new era, unearthing some of science's greatest secrets. |
Free falling in outer space | null | TED-Ed | Have you ever been floating in a swimming pool, all comfy and warm, thinking, "Man, it'd be cool to be an astronaut! You could float out in outer space, look down at the Earth and everything. It'd be so neat!" Only that's not how it is at all. If you are in outer space, you are orbiting the Earth: it's called free fall. You're actually falling towards the Earth. Think about this for a moment: that's the feeling you get if you're going over the top of a roller coaster, going, like, "Whoa!" Only you're doing this the whole time you're orbiting the Earth, for two, three, four hours, days. Whatever it takes, right? So, how does orbiting work? Let's take a page from Isaac Newton. He had this idea, a little mental experiment: You take a cannon, you put it on top of a hill. If you shoot the cannonball, it goes a little bit away. But if you shoot it harder, it goes far enough so that it lands a little bit past the curvature of Earth. Well, you can imagine if you shot it really, really, hard, it would go all the way around the Earth and come back — boom! — and hit you in the backside or something. Let's zoom way back and put you in a little satellite over the North Pole of the Earth and consider north to be up. You're going to fall down and hit the Earth. But you are actually moving sideways really fast. So when you fall down, you're going to miss. You're going to end up on the side of the Earth, falling down, and now the Earth is pulling you back in sideways. So it's pulling you back in and you fall down, and so you miss the Earth again, and now you're under the Earth. The Earth is going to pull you up, but you're moving sideways still. So you're going to miss the Earth again. Now you're on the other side of the Earth, moving upward, and the Earth's pulling you sideways. So you're going to fall sideways, but you're going to be moving up and so you'll miss. Now you're back on top of the Earth again, over the North Pole, going sideways and falling down, and yep — you guessed it. You'll keep missing because you're moving so fast. In this way, astronauts orbit the Earth. They're always falling towards the Earth, but they're always missing, and therefore, they're falling all the time. They feel like they're falling, so you just have to get over it. So technically, if you ran fast enough and tripped, you could miss the Earth. But there's a big problem. First, you have to be going eight kilometers a second. That's 18,000 miles an hour, just over Mach 23! The second problem: If you're going that fast, yes, you would orbit the Earth and come back where you came from, but there's a lot of air in the way, much less people and things. So you would burn up due to atmospheric friction. So, I do not recommend this. |
What can Schrödinger's cat teach us about quantum mechanics? | null | TED-Ed | Consider throwing a ball straight into the air. Can you predict the motion of the ball after it leaves your hand? Sure, that's easy. The ball will move upward until it gets to some highest point, then it will come back down and land in your hand again. Of course, that's what happens, and you know this because you have witnessed events like this countless times. You've been observing the physics of everyday phenomena your entire life. But suppose we explore a question about the physics of atoms, like what does the motion of an electron around the nucleus of a hydrogen atom look like? Could we answer that question based on our experience with everyday physics? Definietly not. Why? Because the physics that governs the behavior of systems at such small scales is much different than the physics of the macroscopic objects you see around you all the time. The everyday world you know and love behaves according to the laws of classical mechanics. But systems on the scale of atoms behave according to the laws of quantum mechanics. This quantum world turns out to be a very strange place. An illustration of quantum strangeness is given by a famous thought experiment: Schrödinger's cat. A physicist, who doesn't particularly like cats, puts a cat in a box, along with a bomb that has a 50% chance of blowing up after the lid is closed. Until we reopen the lid, there is no way of knowing whether the bomb exploded or not, and thus, no way of knowing if the cat is alive or dead. In quantum physics, we could say that before our observation the cat was in a superposition state. It was neither alive nor dead but rather in a mixture of both possibilities, with a 50% chance for each. The same sort of thing happens to physical systems at quantum scales, like an electron orbiting in a hydrogen atom. The electron isn't really orbiting at all. It's sort of everywhere in space, all at once, with more of a probability of being at some places than others, and it's only after we measure its position that we can pinpoint where it is at that moment. A lot like how we didn't know whether the cat was alive or dead until we opened the box. This brings us to the strange and beautiful phenomenon of quantum entanglement. Suppose that instead of one cat in a box, we have two cats in two different boxes. If we repeat the Schrödinger's cat experiment with this pair of cats, the outcome of the experiment can be one of four possibilities. Either both cats will be alive, or both will be dead, or one will be alive and the other dead, or vice versa. The system of both cats is again in a superposition state, with each outcome having a 25% chance rather than 50%. But here's the cool thing: quantum mechanics tells us it's possible to erase the both cats alive and both cats dead outcomes from the superposition state. In other words, there can be a two cat system, such that the outcome will always be one cat alive and the other cat dead. The technical term for this is that the states of the cats are entangled. But there's something truly mindblowing about quantum entanglement. If you prepare the system of two cats in boxes in this entangled state, then move the boxes to opposite ends of the universe, the outcome of the experiment will still always be the same. One cat will always come out alive, and the other cat will always end up dead, even though which particular cat lives or dies is completely undetermined before we measure the outcome. How is this possible? How is it that the states of cats on opposite sides of the universe can be entangled in this way? They're too far away to communicate with each other in time, so how do the two bombs always conspire such that one blows up and the other doesn't? You might be thinking, "This is just some theoretical mumbo jumbo. This sort of thing can't happen in the real world." But it turns out that quantum entanglement has been confirmed in real world lab experiments. Two subatomic particles entangled in a superposition state, where if one spins one way then the other must spin the other way, will do just that, even when there's no way for information to pass from one particle to the other indicating which way to spin to obey the rules of entanglement. It's not surprising then that entanglement is at the core of quantum information science, a growing field studying how to use the laws of the strange quantum world in our macroscopic world, like in quantum cryptography, so spies can send secure messages to each other, or quantum computing, for cracking secret codes. Everyday physics may start to look a bit more like the strange quantum world. Quantum teleportation may even progress so far, that one day your cat will escape to a safer galaxy, where there are no physicists and no boxes. |
The evolution of the human eye | null | TED-Ed | The human eye is an amazing mechanism, able to detect anywhere from a few photons to direct sunlight, or switch focus from the screen in front of you to the distant horizon in a third of a second. In fact, the structures required for such incredible flexibility were once considered so complex that Charles Darwin himself acknowledged that the idea of there having evolved seemed absurd in the highest possible degree. And yet, that is exactly what happened, starting more than 500 million years ago. The story of the human eye begins with a simple light spot, such as the one found in single-celled organisms, like euglena. This is a cluster of light-sensitive proteins linked to the organism's flagellum, activating when it finds light and, therefore, food. A more complex version of this light spot can be found in the flat worm, planaria. Being cupped, rather than flat, enables it to better sense the direction of the incoming light. Among its other uses, this ability allows an organism to seek out shade and hide from predators. Over the millenia, as such light cups grew deeper in some organisms, the opening at the front grew smaller. The result was a pinhole effect, which increased resolution dramatically, reducing distortion by only allowing a thin beam of light into the eye. The nautilus, an ancestor of the octopus, uses this pinhole eye for improved resolution and directional sensing. Although the pinhole eye allows for simple images, the key step towards the eye as we know it is a lens. This is thought to have evolved through transparent cells covering the opening to prevent infection, allowing the inside of the eye to fill with fluid that optimizes light sensitivity and processing. Crystalline proteins forming at the surface created a structure that proved useful in focusing light at a single point on the retina. It is this lens that is the key to the eye's adaptability, changing its curvature to adapt to near and far vision. This structure of the pinhole camera with a lens served as the basis for what would eventually evolve into the human eye. Further refinements would include a colored ring, called the iris, that controls the amount of light entering the eye, a tough white outer layer, known as the sclera, to maintain its structure, and tear glands that secrete a protective film. But equally important was the accompanying evolution of the brain, with its expansion of the visual cortex to process the sharper and more colorful images it was receiving. We now know that far from being an ideal masterpiece of design, our eye bares traces of its step by step evolution. For example, the human retina is inverted, with light-detecting cells facing away from the eye opening. This results in a blind spot, where the optic nerve must pierce the retina to reach the photosensitive layer in the back. The similar looking eyes of cephalopods, which evolved independently, have a front-facing retina, allowing them to see without a blind spot. Other creatures' eyes display different adaptations. Anableps, the so called four-eyed fish, have eyes divided in two sections for looking above and under water, perfect for spotting both predators and prey. Cats, classically nighttime hunters, have evolved with a reflective layer maximizing the amount of light the eye can detect, granting them excellent night vision, as well as their signature glow. These are just a few examples of the huge diversity of eyes in the animal kingdom. So if you could design an eye, would you do it any differently? This question isn't as strange as it might sound. Today, doctors and scientists are looking at different eye structures to help design biomechanical implants for the vision impaired. And in the not so distant future, the machines built with the precision and flexibilty of the human eye may even enable it to surpass its own evolution. |
The myth of Icarus and Daedalus | null | TED-Ed | In mythological ancient Greece, soaring above Crete on wings made from wax and feathers, Icarus, the son of Daedalus, defied the laws of both man and nature. Ignoring the warnings of his father, he rose higher and higher. To witnesses on the ground, he looked like a god, and as he peered down from above, he felt like one, too. But, in mythological ancient Greece, the line that separated god from man was absolute and the punishment for mortals who attempted to cross it was severe. Such was the case for Icarus and Daedalus. Years before Icarus was born, his father Daedalus was highly regarded as a genius inventor, craftsman, and sculptor in his homeland of Athens. He invented carpentry and all the tools used for it. He designed the first bathhouse and the first dance floor. He made sculptures so lifelike that Hercules mistook them for actual men. Though skilled and celebrated, Daedalus was egotistical and jealous. Worried that his nephew was a more skillful craftsman, Daedalus murdered him. As punishment, Daedalus was banished from Athens and made his way to Crete. Preceded by his storied reputation, Daedalus was welcomed with open arms by Crete's King Minos. There, acting as the palace technical advisor, Daedalus continued to push the boundaries. For the king's children, he made mechanically animated toys that seemed alive. He invented the ship's sail and mast, which gave humans control over the wind. With every creation, Daedalus challenged human limitations that had so far kept mortals separate from gods, until finally, he broke right through. King Minos's wife, Pasiphaë, had been cursed by the god Poseidon to fall in love with the king's prized bull. Under this spell, she asked Daedalus to help her seduce it. With characteristic audacity, he agreed. Daedalus constructed a hollow wooden cow so realistic that it fooled the bull. With Pasiphaë hiding inside Daedalus's creation, she conceived and gave birth to the half-human half-bull minotaur. This, of course, enraged the king who blamed Daedalus for enabling such a horrible perversion of natural law. As punishment, Daedalus was forced to construct an inescapable labyrinth beneath the palace for the minotaur. When it was finished, Minos then imprisoned Daedalus and his only son Icarus within the top of the tallest tower on the island where they were to remain for the rest of their lives. But Daedalus was still a genius inventor. While observing the birds that circled his prison, the means for escape became clear. He and Icarus would fly away from their prison as only birds or gods could do. Using feathers from the flocks that perched on the tower, and the wax from candles, Daedalus constructed two pairs of giant wings. As he strapped the wings to his son Icarus, he gave a warning: flying too near the ocean would dampen the wings and make them too heavy to use. Flying too near the sun, the heat would melt the wax and the wings would disintegrate. In either case, they surely would die. Therefore, the key to their escape would be in keeping to the middle. With the instructions clear, both men leapt from the tower. They were the first mortals ever to fly. While Daedalus stayed carefully to the midway course, Icarus was overwhelmed with the ecstasy of flight and overcome with the feeling of divine power that came with it. Daedalus could only watch in horror as Icarus ascended higher and higher, powerless to change his son's dire fate. When the heat from the sun melted the wax on his wings, Icarus fell from the sky. Just as Daedalus had many times ignored the consequences of defying the natural laws of mortal men in the service of his ego, Icarus was also carried away by his own hubris. In the end, both men paid for their departure from the path of moderation dearly, Icarus with his life and Daedalus with his regret. |
The sonic boom problem | null | TED-Ed | Humans have been fascinated with speed for ages. The history of human progress is one of ever-increasing velocity, and one of the most important achievements in this historical race was the breaking of the sound barrier. Not long after the first successful airplane flights, pilots were eager to push their planes to go faster and faster. But as they did so, increased turbulence and large forces on the plane prevented them from accelerating further. Some tried to circumvent the problem through risky dives, often with tragic results. Finally, in 1947, design improvements, such as a movable horizontal stabilizer, the all-moving tail, allowed an American military pilot named Chuck Yeager to fly the Bell X-1 aircraft at 1127 km/h, becoming the first person to break the sound barrier and travel faster than the speed of sound. The Bell X-1 was the first of many supersonic aircraft to follow, with later designs reaching speeds over Mach 3. Aircraft traveling at supersonic speed create a shock wave with a thunder-like noise known as a sonic boom, which can cause distress to people and animals below or even damage buildings. For this reason, scientists around the world have been looking at sonic booms, trying to predict their path in the atmosphere, where they will land, and how loud they will be. To better understand how scientists study sonic booms, let's start with some basics of sound. Imagine throwing a small stone in a still pond. What do you see? The stone causes waves to travel in the water at the same speed in every direction. These circles that keep growing in radius are called wave fronts. Similarly, even though we cannot see it, a stationary sound source, like a home stereo, creates sound waves traveling outward. The speed of the waves depends on factors like the altitude and temperature of the air they move through. At sea level, sound travels at about 1225 km/h. But instead of circles on a two-dimensional surface, the wave fronts are now concentric spheres, with the sound traveling along rays perpendicular to these waves. Now imagine a moving sound source, such as a train whistle. As the source keeps moving in a certain direction, the successive waves in front of it will become bunched closer together. This greater wave frequency is the cause of the famous Doppler effect, where approaching objects sound higher pitched. But as long as the source is moving slower than the sound waves themselves, they will remain nested within each other. It's when an object goes supersonic, moving faster than the sound it makes, that the picture changes dramatically. As it overtakes sound waves it has emitted, while generating new ones from its current position, the waves are forced together, forming a Mach cone. No sound is heard as it approaches an observer because the object is traveling faster than the sound it produces. Only after the object has passed will the observer hear the sonic boom. Where the Mach cone meets the ground, it forms a hyperbola, leaving a trail known as the boom carpet as it travels forward. This makes it possible to determine the area affected by a sonic boom. What about figuring out how strong a sonic boom will be? This involves solving the famous Navier-Stokes equations to find the variation of pressure in the air due to the supersonic aircraft flying through it. This results in the pressure signature known as the N-wave. What does this shape mean? Well, the sonic boom occurs when there is a sudden change in pressure, and the N-wave involves two booms: one for the initial pressure rise at the aircraft's nose, and another for when the tail passes, and the pressure suddenly returns to normal. This causes a double boom, but it is usually heard as a single boom by human ears. In practice, computer models using these principles can often predict the location and intensity of sonic booms for given atmospheric conditions and flight trajectories, and there is ongoing research to mitigate their effects. In the meantime, supersonic flight over land remains prohibited. So, are sonic booms a recent creation? Not exactly. While we try to find ways to silence them, a few other animals have been using sonic booms to their advantage. The gigantic Diplodocus may have been capable of cracking its tail faster than sound, at over 1200 km/h, possibly to deter predators. Some types of shrimp can also create a similar shock wave underwater, stunning or even killing pray at a distance with just a snap of their oversized claw. So while we humans have made great progress in our relentless pursuit of speed, it turns out that nature was there first. |
The paradox of value | null | TED-Ed | Imagine you're on a game show, and you can choose between two prizes: a diamond or a bottle of water. It's an easy choice. The diamonds are clearly more valuable. Now imagine being given the same choice again, only this time, you're not on a game show, but dehydrated in the desert after wandering for days. Do you choose differently? Why? Aren't diamonds still more valuable? This is the paradox of value, famously described by pioneering economist Adam Smith. And what it tells us is that defining value is not as simple as it seems. On the game show, you were thinking about each item's exchange value, what you could obtain for them at a later time, but in an emergency, like the desert scenario, what matters far more is their use value, how helpful they are in your current situation. And because we only get to choose one of the options, we also have to consider its opportunity cost, or what we lose by giving up the other choice. After all, it doesn't matter how much you could get from selling the diamond if you never make it out of the desert. Most modern economists deal with the paradox of value by attempting to unify these considerations under the concept of utility, how well something satisfies a person's wants or needs. Utility can apply to anything from the basic need for food to the pleasure of hearing a favorite song, and will naturally vary for different people and circumstances. A market economy provides us with an easy way to track utility. Put simply, the utility something has to you is reflected by how much you'd be willing to pay for it. Now, imagine yourself back in the desert, only this time, you get offered a new diamond or a fresh bottle of water every five minutes. If you're like most people, you'll first choose enough water to last the trip, and then as many diamonds as you can carry. This is because of something called marginal utility, and it means that when you choose between diamonds and water, you compare utility obtained from every additional bottle of water to every additional diamond. And you do this each time an offer is made. The first bottle of water is worth more to you than any amount of diamonds, but eventually, you have all the water you need. After a while, every additional bottle becomes a burden. That's when you begin to choose diamonds over water. And it's not just necessities like water. When it comes to most things, the more of it you acquire, the less useful or enjoyable every additional bit becomes. This is the law of diminishing marginal utility. You might gladly buy two or three helpings of your favorite food, but the fourth would make you nauseated, and the hundredth would spoil before you could even get to it. Or you could pay to see the same movie over and over until you got bored of it or spent all of your money. Either way, you'd eventually reach a point where the marginal utility for buying another movie ticket became zero. Utility applies not just to buying things, but to all our decisions. And the intuitive way to maximize it and avoid diminishing returns is to vary the way we spend our time and resources. After our basic needs are met, we'd theoretically decide to invest in choices only to the point they're useful or enjoyable. Of course, how effectively any of us manage to maximize utility in real life is another matter. But it helps to remember that the ultimate source of value comes from us, the needs we share, the things we enjoy, and the choices we make. |
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