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jn7qg | the casimir effect | I tried reading the Wikipedia article, but it loses me pretty quickly. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/jn7qg/eli5_the_casimir_effect/ | {
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"I'm a grad student working with the Casimir force right now. I'll admit, my theoretical knowledge isn't complete, but I'll give the best explanation I can. \n\nSo at a really, really small level, light is popping into existence and then going right back into nothing. It's doing this all around you right now.\n\nIf you take two flat things, and move them very close together (like 1/10 of a human hair), only certain color light can come into existence between the flat objects. Other colors won't fit. \n\nOn the other side of the flat plates, the light can exist in a lot more colors. The difference in the colors possible make a different amount of energy between the plates as compared to outside the plates. This difference in energy shows up as the casimir effect.\n\nTo get a visual idea of what's happening, take two sheets of paper, hold them in front of your face, and blow in between them. The blowing makes the air pressure lower on the inside of the paper, and the paper should move towards each other.",
"Imagine you and a friend are standing still, but you are 20 feet apart. There is a swarm of people stomping around randomly. The crowd is so thick people are nearly touching all of the time, like at a concert. You get pushed around, back and forth randomly, but you and your friend stay roughly the same distance apart. Now, lets say you get close enough to your friend that it's harder and harder for someone to get in between you, eventually the crowd will push you together, because there is nothing between you to push you apart, and the only force on your is from the outside.\n\nNow imagine that you and your buddy are the plates and that different frequencies of energy are the people.\n",
"Great explanation. I also thought it was very well illustrated in the book The Light of Other Days by Arthur C. Clarke.",
"I'm a grad student working with the Casimir force right now. I'll admit, my theoretical knowledge isn't complete, but I'll give the best explanation I can. \n\nSo at a really, really small level, light is popping into existence and then going right back into nothing. It's doing this all around you right now.\n\nIf you take two flat things, and move them very close together (like 1/10 of a human hair), only certain color light can come into existence between the flat objects. Other colors won't fit. \n\nOn the other side of the flat plates, the light can exist in a lot more colors. The difference in the colors possible make a different amount of energy between the plates as compared to outside the plates. This difference in energy shows up as the casimir effect.\n\nTo get a visual idea of what's happening, take two sheets of paper, hold them in front of your face, and blow in between them. The blowing makes the air pressure lower on the inside of the paper, and the paper should move towards each other.",
"Imagine you and a friend are standing still, but you are 20 feet apart. There is a swarm of people stomping around randomly. The crowd is so thick people are nearly touching all of the time, like at a concert. You get pushed around, back and forth randomly, but you and your friend stay roughly the same distance apart. Now, lets say you get close enough to your friend that it's harder and harder for someone to get in between you, eventually the crowd will push you together, because there is nothing between you to push you apart, and the only force on your is from the outside.\n\nNow imagine that you and your buddy are the plates and that different frequencies of energy are the people.\n",
"Great explanation. I also thought it was very well illustrated in the book The Light of Other Days by Arthur C. Clarke."
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1jf7ri | why is there the colours in vertical stripes on when you put in an old vcr tape? | Im curious if it serves a purpose or if its just a colour test or glitch? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1jf7ri/eli5_why_is_there_the_colours_in_vertical_stripes/ | {
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"It is a color test that the consumer can use to adjust the color saturation on their television. It was produced by the Society of Motion Picture and Television Engineers and is refereed to as the SMPTE color bars"
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18nb5t | the movie primer (spoilers) | I just finished this movie and here's what I got.
1. They created a time machine.
2. They wanted to use it to make money from March Madness.
3. Aaron wanted to use it for his own selfish needs and to save someone from getting murdered with a shotgun?
4. Aaron fucks everything up.
That's what I concluded from the story and I don't think it's right. Someone please explain this movie like I'm 5. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/18nb5t/eli5_the_movie_primer_spoilers/ | {
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"Everything after your #1 is pretty far off the mark.\n\nThey didn't make money from sports betting. They made money from the stock market. Every afternoon they checked the closing prices of different stocks and looked for one that gained a lot of value over the day, but that traded in very large volume. Then they waited in the box until it was that morning again, bought as many shares of that stock as they could get away with at the low opening price, then waited until the end of the day when the price was much higher to put in sell orders and take their profits.\n\nThey did this a few times — the movie doesn't say exactly how many times — and it got to the point where both Abe and Aaron had enough money that they could imagine never having to work again in their lives. Which got them thinking about what to do next. There's no point in continuing to work thirty-six-hour days to make money in the market, since they've got more money than they need already. So … what? What do they do now?\n\nAaron had the idea to use the boxes *just once* to pull off what basically amounted to a petty prank. See, Aaron had been in business with a guy who'd treated him badly, and he really wanted to just punch that guy in the mouth, just once. But he knew that would be a bad idea … but what if he could both do it *and not do it?* What if he could go find the guy and punch him, then use the box to relive that day and *not* punch him? Does time even *work* that way?\n\nThat's the central theme of the movie, incidentally. *Neither Abe nor Aaron have any idea how time works.* They built the box by *accident,* not on purpose. They didn't actually know what they were doing. They know the basics: Get in the box and you oscillate back and forth between two points in time, and you can choose which one to get out at. But they don't know *anything* else. The movie illustrates this with the mobile-phone thing. One day Aaron mistakenly keeps his mobile phone with him when they do their second trip through the day … meaning there are now *two* phones out there. When Aaron's wife calls his mobile, which phone rings? Both of them? Just the first one? Is what they're observing the second time through their day just a different perspective on what happened their first time through, or is it fundamentally different? *They don't know.* That's the point. They have no idea what they're doing.\n\nBut one night, Abe thinks of a clever way to test it out. He's awakened in the middle of the night by some kids setting off car alarms. He figures that they can do an experiment: Go do something, doesn't matter what really, just something they can check up on later. Then use the boxes to go back to before those kids set off the car alarm that woke Abe up in the first place, and prevent them from doing it. No car alarm means Abe doesn't wake up, which means they don't do the thing, which means they don't use the boxes, which means they don't prevent the kids from setting off the alarms, which means … what? *They don't know.* That's the point. The characters do not know what would happen. But they're smart and curious, so they decide to try it and see.\n\nOnly they never get to do their experiment, because they're interrupted by the sudden appearance of a guy named Granger who has *apparently* used a box himself. What box did he use? When did he use it? *Why* did he use it? The characters don't know, and neither do we.\n\nBut this situation freaks Abe out so much he decides to use his failsafe box. After he understood what the boxes could do but before he told Aaron about them, he built and started a secret box that only he knew about. He did this so he could, if he needed to, use that box at any time in the future, go back to before *any* of this stuff started, and … something. Change the events, maybe. Or maybe not, *he doesn't know,* but he figures it's worth at least having the option, just in case time works the way it does in sci-fi movies.\n\nSo when Granger shows up and Abe realizes that the boxes are no longer a secret, he decides to use the failsafe in an *attempt* — which he can't know will succeed, but hopes anyway because by this point he's scared and desperate — to go back and fix things.\n\nExcept when he gets back to the beginning, he finds Aaron's already there, waiting for him. Aaron found Abe's failsafe box much earlier, and used it himself. So Abe finds that not only does he not have everything under control, he doesn't even have the *option* of getting things under control any more. The genie's out of the bottle; Abe can't undo what he's done.\n\nThis legitimately freaks him the hell out. The shock of learning that Aaron had been at least a step ahead of him the whole time, combined with simple exhaustion — remember, these guys haven't exactly been sleeping regularly since they started messing with the boxes — basically knocks him on his butt for a while. The whole situation's become so complex, so incomprehensible, that he decides to just bail on it. That's when he and Aaron have their conversation (fight, almost) at the airport. Abe's terrified of time now, not because he understands it, but because he understands that *he doesn't understand it.* He doesn't know if anybody can understand it; the human mind wasn't meant to deal with concepts like that. So he just wants out. He wants it all to stop.\n\nAaron, on the other hand? Aaron's the arrogant one. He thinks he does understand time. Which is why he's the one who ends up, at the end of the film (which is not the end of the story, but rather the beginning of the story) off somewhere out in the world building a bigger box. A much bigger box.\n\nBecause Aaron's got *plans.*"
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8f5g4y | is there a good reason why we need to wear socks with shoes? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/8f5g4y/eli5_is_there_a_good_reason_why_we_need_to_wear/ | {
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"Reduce friction. Absorb sweat. Keep insides of shoes cleaner, fresher. Adjust fit of loose shoes.\n\nI've searched tha seven seas fer an answer. Yer not alone in askin', and kind strangers have explained:\n\n1. [ELI5: why do we wear socks with closed shoes? ](_URL_0_) ^(_5 comments_)\n1. [ELI5: Why does putting socks, which cover around 5% of my body, make me feel significantly warmer? ](_URL_1_) ^(_ > 100 comments_)\n1. [Why do we wear socks? ](_URL_2_) ^(_8 comments_)\n",
"Ever wear sneakers or other closed shoes without socks?\n\nYour feet will sweat, and there's nowhere for that sweat to go. If you're wearing sandals it can evaporate, but in a closed shoe it puddles and becomes a breeding ground for bacteria. This makes your feet stink.\n\nThen all that pooled sweat and bacteria, which still can't evaporate, has nowhere to go except soaking into your shoes. So now your shoes stink. And shoes are hard to get clean. Some can go through the wash, but if they're leather it's going to be a lot harder.\n\nPlus, sweaty feet generate a lot of friction. With nothing between your sweaty feet and the show, that leads to blisters.\n\nSocks fix all the above problems. They soak up the sweat and are easy to clean, and give a barrier to reduce friction between your foot and the shoe."
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60pa6z | what scientifically stops us from creating life? | We know what we are made of but what stops life from starting when we put the necessary ingredients together?
Edit: I'm not talking about creating another human. But just a small single celled form of life. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/60pa6z/eli5_what_scientifically_stops_us_from_creating/ | {
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"We can't put them together from scratch yet. Close, but not quite. \n\nAlso, life is a dangerous thing...there's the \"wipe out all other life on Earth\" possibility to deal with.",
"We've replaced the genetic material in simple cells with a synthetic genome and fired them back up.\n\nAll that's really limiting us from building complete cells from scratch is the fabrication of complex cell components. Biological systems are capable of extremely fine chemical assembly that we can't replicate in a lab mechanically.\n\nWe can use other cells to build the parts we want, but that's not quite the same.\n\nFor more complex life you have to deal with more sophisticated genetic code and layers of gene regulation that we don't fully understand yet.",
"We are trying, but it is *fucking hard*. It's not like we can precisely manipulate individual atoms and molecules as if they were Lego bricks.",
"Because we simply cannot craft matter at the molecular level as we please.\n\nThe basic molecules needed for life are astronomically complex. And nature itself did not create them overnight. They slowly evolved from simpler structures over time. Life did not just spark into existence, it was conceived by a long sequence of very lucky developments.\n\nThe DNA itself is composed of proteins, which are themselves composed of amino acids, which are still quite complex and varied. And we can't just link atoms together like Lego blocks.\n\nIf that was that easy, our planet would have had more than one life outburst. Instead, all known life on planet can be traced back to a single event.\n",
"\"Creating life\" in this context would refer to a very simple life-form. One of the most important steps for this is creating a lipid bi-layer of some sort, which is what most likely happened when the first lifeforms on earth came to be. Luckily this happens relatively easy, when molecules that have a hydrophobic and hydrophilic part clump together, as this creates a semi-permeable membrane that is able to selectively let through certain molecules (think food and oxygen), and creates a stable environment for the cell-to-be. This is the same thing that happens as when soap bubbles form.\n\nThe next important step is taking in amino acids, which are the molecules that form DNA. It has already been proven that these amino acids can form in something we call \"primordial soup\" when electricity is applied (thunder for example). With a bit of luck, a very simple functional strand of DNA is formed, and with even more luck, the formed DNA is functional enough to have it start simple metabolism and reproduction. \n\nThe difficulty in creating this ourselves (and the answer to your question) is the sheer number of times this has to happen before we get lucky enough that something functional forms. Life being created is incredibly improbable, but given enough time (hundreds of millions of years), the process happens so often, life might actually form.\n\nI need to add that i left out a lot of stuff and loads of it is slightly incorrect for the sake of simplicity, but the general idea is correct. ",
"By some definitions, we already have. We can create 100% artificial DNA, use it to replace the DNA in a single celled organism, and get a new, novel lifeform that uses that synthetic DNA.\n\nWhat we can't do is create everything from scratch, we still need a natural organism to kick start it. The question is when does that become creating life? If I use one lifeform to create something completely new and difference, does that count?",
"Mostly because a lot of the critical parts are so incredibly small and delicate. We don't have tools to build something like that."
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9gl8uc | how did people subsist on mostly grains in the past? iow, why did a failed wheat harvest cause a famine? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/9gl8uc/eli5_how_did_people_subsist_on_mostly_grains_in/ | {
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"Grain-based foods like bread or rice are pretty much the most efficient calorie delivery mechanism available. Today we think about watching what we eat and trying not to get fat, but in those days the main concern was not starving to death. Bread was cheap, really cheap, and since the vast majority of the population lived in grinding poverty while doing lots of calorie-burning manual labor all day long it was the best thing for them to eat. Depending on where you lived you might be able to supplement your diet with vegetables or fish, but bread would be the main thing that filled your belly.\n\nThe word famine comes to us from the Latin *fames*, which means hunger. Anything from a flood to a drought to a disruption in transportation of grain could cause a famine, and it would mean that all the poor people who could barely afford to eat bread would have nothing.",
"Well first of all we still subsist mostly on grains. We can divide our diet into four main source of calories. 1) Carbohydrates : that mostly come from grains, but also from sugar, which wasn't that available in the past. (At least not like today), 2) Fat, 3) Plant Protein and 4) Animal Protein.\n\nOn average in the US almost 50% of the daily calories come from carbohydrates. (I wasn't able to find how much of that come from sugar vs gains). So even today, grains represent a large portion of our diet and if wheat or other grains harvest would fail on a large scale, we would have famine.\n\nSource : _URL_0_\n\nAs you can see in the graphic, in the last 50 years we slighting increase our carbohydrates consumption (My guess is more sugar), but not by much. It's mostly fat that increased a lot since 1960. So in the past we were more dependant on grains, because sugar wasn't as available as it is today and fat usually come from more expensive source of food. It cost more to get beef on the table than some bread.\n\nSo in the past, an even large portion of our diet was dependent on grains, simply because it was an efficient way to produce food and food was more scare bad then.\n\nTransportation was also less developed in the past, so if there was a problem with an harvest in a region, it was harder to transport food from somewhere else to feed people.\n\nAnd finally, government was less powerful, so they didn't have that much control over what was happening in some region. They simply didn't have the resources or the obligation to do something about a region having a bad harvest. Today, there is organisation in place to respond to crisis to prevent famine in most developed countries and if people in government failed to respond, they might be taken to court for that inactivity. Something that wouldn't happen in the past.\n\n",
"Grains get you the most calories per acre and were responsible for a huge population boom (with the occasional famine) when humans started cultivating them about 10,000 years ago. That calorie surplus let people do things other than search for enough food to eat all day, things like crafting or trading or soldiering, things that lead to a more developed society.\n\nFamine did lead to widespread hunger and death, but those were people who wouldn't have existed in the first place without a grain-based food economy.",
"For most of human history we lived a life of subsistence. The net total of all of the food that we grew, hunted, raised, and gathered in a year were at or just slightly above the amount we needed to not starve. Any disruption of the crops, bad run of hunting etc would cause famine. Note this is not just grains, it is all food sources. Have a early frost that killed the crops and people starved, have a bad hunt too often and people starved, have a blight or disease come through the crops or livestock and people starved. We did not have stable surpluses in food supply until the early 1800s when agricultural methods improved enough to have major surpluses from year to year. "
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8e513b | why does one get paranoid at times? in other words, are there receptors for paranoia in the body? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/8e513b/eli5_why_does_one_get_paranoid_at_times_in_other/ | {
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"The endocrine system regulates your flight or fight response, releasing various chemicals that attach to your receptors and make you feel scared.\n\nParanoia is a reaction to fear, such as is anger.\nIf there is no immediate threat, your brain is going to rationalize your fear.\n\nIt's why we get pissed when someone pulls out in front of us, or laugh when we get a jumpscare. It's our brain rationalizing fear into something we can process consciously.\n\nBoo!\n\nYou could have anxiety or something, but cannabis will also cause random paranoia even when you haven't smoked it in a while.\n\nGood luck."
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6kbhfu | how is netflix cheaper than cable without ads while cable has them? shouldn't it be the other way around ? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/6kbhfu/eli5_how_is_netflix_cheaper_than_cable_without/ | {
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"Netflix is about the same price per month as a premium cable station like HBO or Showtime. So, I am not sure why you think it's substantially cheaper.\n\nIf you are comparing Netflix to cable service as a whole, remember that the cable bill includes getting the content to your house. Netflix doesn't cover that.",
"When cable TV was first introduced, the main selling point (wait...PAY?? For TV??!!) was that it didn't have commercials. Guess how long that lasted. Give Netflix another decade or so.",
"Because Netflix uses the internet to deliver content, and you pay for internet service separately. All together the price isn't all that different",
"While it is true that you pay for delivery as part of your cable bill...\n\nCable has (to some extent) a \"monopoly\" on certain types of content, especially live sports and news. They charge more because some people are willing to pay, partly because of lack of options (for that type of content). \n\nCable companies are also constantly criticized and sometimes sued for unfair or unclear fee structures, including stuff like equipment rental fees being overcharged or billed incorrectly. \n\nYes, there are concrete reasons why cable may be more expensive to deliver to you. But a lot of it comes down to business practices. Netflix wants to continue getting your money because you're happy with their product and the value it offers. Cable companies want to get as much money as possible from you per-month and they're willing to have people leave their service if it means they can continue price-gouging their loyal customers. "
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f97aop | why can't engineers remove the violent left/right movement and shakes of trains better? | If you ever try to stand and pee on a train, it is very noticeable how it shakes left and right between the rails. This seems like an inefficient waste of energy and a burden on the train's suspension and structure. It is also uncomfortable.
The train in question is a relatively new Stadler Flirt, but the same issue is valid for all non-highspeed trains. The rails are, in part, quite old. But I figure their inaccuracies should still be possible to smooth out?
So, question, why aren't train engineers improving the ride way more than they already do? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/f97aop/eli5_why_cant_engineers_remove_the_violent/ | {
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"The technology exists, but it's too expensive so most manufacturers don't bother because rail companies won't buy it.",
"The simple fix is to stagger the rails instead of them being like ========= they should be like \"-\"- (where the quotes are offset rails) it makes trains far quieter and far less \"rocky\" from side to side, however, the increase in cost for laying track like that is higher than you would expect. The GO Train in Toronto is an example of how quiet and less \"rocky\" but I haven't seen it replicated anywhere else in north America (not that I've been on trains in every part of NA)."
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16nk8u | frost at above-freezing temperatures | Often, in California, the low drops to around 35 F on some winter nights. Despite the freezing point never having been reached, my car often accumulates a thick layer of frost. Why does this happen? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/16nk8u/eli5_frost_at_abovefreezing_temperatures/ | {
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"You (or the weatherman) are measuring the temperature of the air. You should try taking the temperature of the car. "
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1j5w25 | how close are we to build engines capable of travelling at roughly the speed of light? | I often hear about how we some day will be able to travel at the speed of light. But how close are we exactly and what would have to happen in order to build this kind of engines/spaceships? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1j5w25/eli5_how_close_are_we_to_build_engines_capable_of/ | {
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" > How close are we to build engines capable of travelling at roughly the speed of light?\n\nNot even remotely close.\n\n > I often hear about how we some day will be able to travel at the speed of light.\n\nIf our current understanding of physics is correct we will never be able to travel at or faster than the speed of light. We may eventually be able to \"trick\" the universe into letting us pass between places faster than light, but we will never be able to traverse the distance between them at or above the speed of light. \n > But how close are we exactly and what would have to happen in order to build this kind of engines/spaceships?\n\nRight now our current technology doesn't make this a viable option. Right now we don't have a ship capable of reaching another planet, or even the moon.\n\nThe biggest problem with using our current technology to attempt relativistic speeds (this is below the speed of light, but still really fast), which is how fast we would need to travel if we want to travel between stars, is that you need to use fuel to accelerate, and keep using fuel the entire time. This means that as you need to carry **massive** amounts of fuel in order to go very fast, because that first fuel you use has to accelerate all the extra fuel you're carrying. As you use fuel this becomes more efficient - but I'm about to throw another wrench in the works - but you still need to carry enough fuel to *stop* you when you get to your destination.\n\nBasically, by the time you're finished figuring out how much fuel you need, the amount of fuel you would need becomes unrealistically huge with our current technology. ",
"On a scale from 1 to 10? A low 1.",
"The fastest we've ever gotten a spacecraft is around 37,000 mph (depending on how you measure it, I guess), and that number is misleading because the probe used gravity to get up to that speed. The speed of light is around 650,000,000 mph.\n\nThat means we've gotten to around .005% of the speed of light, and we cheated a lot to get there. Not even *remotely* close."
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bi00fk | why does tapping wood and tapping metal produce different sounds? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/bi00fk/eli5_why_does_tapping_wood_and_tapping_metal/ | {
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"you know when you put a ruler on the edge of a table and push it down and let it go and it makes that woioioioinggggg sound? And if you vary the length of it off the table, the sound changes and the speed at which the end of the ruler goes up and back down changes? This is the natural frequency of the ruler when it is that length of the table and thus produces a certain sound. \n\nNow certain materials also will have a natural frequency such as wooden or metal tables and that's why they make different sounds. They make different frequencies because they also will only take in set amounts of energies.",
"Sound is basically caused by our eardrums reacting to different frequency vibrations, and our brain interpreting the vibrations as sounds. Different frequencies will cause different sounds, because the vibrations are different.\n\nDeeper sounds are caused by lower/shorter frequencies/vibrations, while higher sounds are caused by higher/longer frequencies/vibrations.\n\nThe reason those objects make different sounds will be due to a lot of things, but mostly due to being made of different elements, and having different densities. Both objects cause different types of vibrations, so you hear different sounds.",
"Hey, one that I can answer. Nice. \n\nWood and metal are very different materials. Compared to metal, wood is very soft and has loads of super tiny cracks and holes, all of which affect the sound that is made on contact. \n\nMetal tends to \"ring\" when struck. This is because metal objects (especially those meant for beating noises out of) have a very rigid structure, and are very hard. This means that hitting the metal object causes the strike to spread theough the entire object in the form of vibrations, in a far different way than with wood. \n\nI feel like I was rambling a bit. May come revise this later.",
"The short answer is because metals are much springier and thus will vibrate for longer. This has two effects: The sound lasts for longer, so you get ringing, rather than the \"clop\" of wood. Metals also allow for production of higher pitched/ higher frequency sounds, so the specific frequencies that make up the sound produced when striking metal will have a lot more high frequency waves in it. \n\n\nWhy metal supports high frequency sound generation when wood doesn't comes down to differences in molecular structure. The same metallic bonds that give wood its properties of ductility (can be stretched into a wire) and malleability (can be flattened into a sheet) give it it's acoustic, or sound properties. \n\n\nWhy objects produce the characteristic sound they do is a really deep well to plumb, that involves some math, physics, and chemistry. If this sounds interesting to you, start reading up on metallic bonding vs. polymers, normal modes and natural frequencies, frequency spectrum and Fourier transforms, resonance, and phonons."
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13we85 | why does my hair stand up every which way when i wake up? | What makes my hair stay all funky when I wake up in the morning? And why can't I get it to go back down without completely dousing it with water in the shower? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/13we85/eli5_why_does_my_hair_stand_up_every_which_way/ | {
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"I can best explain this by having you pretend you've parted your hair. When you part your hair, you're training it to prefer to stay in one way or another. When you have short hair, or cowlicks as some people call them, you've slept on your hair so that it sticks up at an angle and you've trained it to stay that way. This is usually the result of sliding down your pillow throughout the night because pillows are terribly designed necessities. Water has a lot of wonderful abilities, including strong hydrogen bonds which make it love to stay with other water molecules and its ability to stick to anything that isn't engineered to have it slide off of. It likes to stay with itself, so when it sticks to your hair, it's also sticking to itself and the strength of the water's bonds with other molecules of itself is stronger than your hair's attempts to stay sticking up in a goofy way."
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5cuxt4 | why does all mainstream virus protection software mcafee kasperky norton etc all take 1 hour+ yet malware bytes take 5 mins and actually find the problem? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5cuxt4/eli5why_does_all_mainstream_virus_protection/ | {
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"This is because they have wildly different use cases.\n\nFirst off, don't be fooled by terminology. Just because a software is called \"Antivirus\", it doesn't mean it will only protect you from viruses, which is only a subset of threats out there. This is just a traditional term for anti-malware solutions. \n\nTraditional Antivirus software (like Symantec Endpoint Protection, Kaspersky Endpoint Security, McAfee Antivirus etc.) is used in trying to *protect* your system from malware infections. It will transparently scan everything that goes in and out of your computer for patterns that are known to come from malware. When doing a scan on your hard drive (not the realtime protection most solutions have), it will scan files for certain characteristics, which forces it to take a very thorough look at each individual file. This takes time. They also can prevent execution of malicious files that the user clicked on. Most solutions also have a so-called \"heuristics\" system that can analyze executable files at runtime, and make a decision based on things the program wants to do to the system. This helps protecting the system from unknown malware.\n\nSolutions like Malwarebytes (or MBAM for short) work in a completely different way. They are *not designed to protect your system*. Rather, they help cleaning up infections that already hit you by comparing all your files against files that are known to be malicious, which is a very fast thing to do. They will not prevent the user starting a malware program nor will they do *anything* to program execution at runtime, even if the program is definitely malware. It will *only* help you if you are already infected, and will not stop you from infecting your machine again.\n\n\ntl;dr/Real ELI5: Traditional Virus Protection software works more like a vaccine that can optionally try to find viruses that slipped through. Malwarebytes is like Antibiotics (except that only works for bacteria and fungi, but the analogy works fine), it treats stuff that already infected you but will not prevent further infections. \n\n//edit: Source: Am an IT professional with specialization in information security, work for a partner of multiple antivirus software vendors.\n\n//edit2: MBAM seems to have similar features to commercial AV products when using their Business products. This post is about the free edition everybody means when mentioning MBAM."
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3mo4wc | the newest change in facebook privacy settings. do they actually use my info/pictures/messages? can they actually make my account public? | Many Facebook friends are writing "legally binding" posts about Facebook not having permission to their account information.
A) Does that even work?
B) What does their new privacy updates mean for the everyday Facebooker?
Thanks in advance. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/3mo4wc/eli5_the_newest_change_in_facebook_privacy/ | {
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"This might be what you're talking about, and may help you. I'm not sure without more detail though. _URL_0_",
"No those stupid posts about \"facebook cannot use my information blah blah blah\" do. not. work.\n\nThey fail to realise that when they signed up they accepted the terms and conditions of the site, which also covers any changes or variations to those terms and conditions. Their posts are unenforceable as \"legally binding\".\n\nI cannot answer what the changes will mean. But i doubt it will mean anything at all."
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7wfkk5 | why does heartburn at night cause nightmares and a racing heart? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/7wfkk5/eli5why_does_heartburn_at_night_cause_nightmares/ | {
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"I'm no Dr but I am a chronic sufferer of acid reflux, especially at night. I have never experienced this. It may be psychosomatic. I used to experience muscle spasms and stinging feelings in my back as a child and they were always accompanied by dreams of bee stings. I've experienced these feelings while awake and always assumed the dreams were my brain \"making sense\" of the information it was receiving. The brain likes to fill in blanks, even if it's wrong."
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1rldgl | how do doctors/paramedics know what's wrong with a person if they're unconscious? | For example, if a person is knocked unconscious by an accident, and is injured, how do doctors or paramedics diagnose the patient? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1rldgl/eli5_how_do_doctorsparamedics_know_whats_wrong/ | {
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"By examining the patient for the more common causes of being unconscious. Typically when in an accident it's not going to be totally unexpected that they took a bump to the head if they're unconscious and in most cases unconsciousness doesn't last very long. ",
"Paramedics would usually assess the patient first with a tip to toe survey,this would find anything like lumps bumps and cuts. They also will have basic test equipment for things like blood pressure and sugar. So assuming there are no witnesses they could still reach a reasonable conclusion until they got to the hospital where the doctors have more sensitive test equipment. ",
"C - CATASTROPHIC hemorrhage\n\nA - Airway (is their airway clear? have they chocked on something. is there vomit in the airway?)\n\nB - Breathing ( the air can get in but it can't get in due to the pt not breathing \n\nC - Circulation ( Blood going round and round?)\n\nObservations - HR, Respiratory rate, SP02 (oxygen %), Blood pressure, Blood glucose, Pupil size + reactivity, 12 lead ECG.\n\n\nWith some one in cardiac arrest. you've got the 5 H's and 4 T's \n\n\nH's\n\nHypoxia: low oxygen levels in the blood\n\nHypovolemia: low amount of circulating blood\n\nHyperkalemia or hypokalemia: disturbances in the level of potassium in the blood, and related disturbances of calcium or magnesium levels\n\nHypothermia/Hyperthermia: body temperature not maintained ( no-one is dead until they are warm and dead)\n\nHypoglycemia: Low blood glucose levels - once went to a pt in a GP surgery with ?CVA (stroke) so GP called for an Amb to pick them up. Patient was unconscious on a bed in the surgery. A quick check of this persons blood glucose showed a level of 1.2 (normally 4-7). after getting some IV glucose in they were up and about and back to normal. \n\n\n\nT's\n\nTension pneumothorax: increased pressure in the thoracic cavity, leading to decreased venous return to the heart\n\nTamponade: fluid or blood in the pericardium\n\nToxic and/or therapeutic: chemicals, whether medication or poisoning\n\nThromboembolism - A blockage in the blood vessel. Like those that happen in the coronary arteries which causes heart tissue to die from lack of oxygen."
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1o5i6y | what is tommy john surgery, and why do so many baseball players have it? | I'm a huge cardinals fan and could not be more excited after last nights victory over the pirates. After reviewing out teams injuries many people
(Furcal, Motte, etc.) have season ending Tommy John surgery. Why have the surgery if it will end your season/career? What is wrong with them? Why do so many ballplayers have the surgery? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1o5i6y/eli5_what_is_tommy_john_surgery_and_why_do_so/ | {
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"Tommy John Surgery, known in medical practice as ulnar collateral ligament (UCL) reconstruction, is a surgical graft procedure in which the ulnar collateral ligament in the medial elbow is replaced with a tendon from elsewhere in the body.\n\nThe patient's arm is opened up around the elbow. Holes to accommodate a new tendon are drilled in the ulna and humerus bones of the elbow. A harvested tendon (often the palmaris tendon)—from the forearm of the same or opposite elbow, below the knee (known as the patellar tendon), or from a cadaver—is then woven in a figure-eight pattern through the holes and anchored. The ulnar nerve is usually moved to prevent pain as scar tissue that forms can apply pressure to the nerve.\n\nThe UCL can become stretched, frayed, or torn through the repetitive stress of the throwing motion. The risk of injury to the throwing athlete's ulnar collateral ligament of elbow joint is thought to be extremely high as the amount of stress through this structure approaches its ultimate tensile strength during a hard throw. R.A. Dickey, however, became a very successful Major League Baseball pitcher despite having no UCL in his pitching arm. According to experts he should not be able to throw at all, let alone at a professional level.\n\nWhile many authorities suggest that an individual's style of throwing or the type of pitches they throw are the most important determinant of their likelihood to sustain an injury, the results of a 2002 study suggest that the total number of pitches thrown is the greatest determinant. A 2002 study examined the throwing volume, pitch type, and throwing mechanics of 426 pitchers aged 9 to 14 for one year. Compared to pitchers who threw 200 or fewer pitches in a season, those who threw 201–400, 401–600, 601–800, and 800+ pitches faced an increased risk of 63%, 181%, 234%, and 161% respectively. The types of pitches thrown showed a smaller effect; throwing a slider was associated with an 86% increased chance of elbow injury, while throwing a curveball was associated with an increase in pain. There was only a weak correlation between throwing mechanics perceived as bad and injury-prone. Thus, although there is a large body of other evidence that suggests mistakes in throwing mechanics increase the likelihood of injury it seems that the greater risk lies in the volume of throwing in total. Research into the area of throwing injuries in young athletes has led to age-based recommendations for pitch limits for young athletes.\nIn younger athletes, for whom the growth plate (the medial epicondylar epiphysis) is still open, the force on the inside of the elbow during throwing is more likely to cause the elbow to fail at this point than at the ulnar collateral ligament. This injury is often termed \"Little League elbow\" and can be serious but does not require reconstructing the UCL.\n\nIn some cases baseball pitchers throw harder after the procedure than they did beforehand. As a result, orthopedic surgeons have reported that increasing numbers of parents are coming to them and asking them to perform the procedure on their un-injured sons in the hope that this will increase their performance. However, many people—including Dr. Frank Jobe, the doctor who invented the procedure—believe most post-surgical increases in performance are generally due to two factors. The first is pitchers' increased attention to conditioning. The second is that in many cases it can take several years for the UCL to deteriorate. Over these years the pitcher's velocity will gradually decrease. As a result, it is likely that the procedure simply allows the pitcher to throw at the velocity he could before his UCL started to degrade.\n\n---source: Wikipedia"
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mei7e | why do us universities favor professors who are better at research than teaching? | Seriously, it seems like the people who are experts in their fields show up, read off slides, then allow TAs to do the hard work because they are too busy with their research to teach. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/mei7e/eli5_why_do_us_universities_favor_professors_who/ | {
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"Guess which one makes them more money, and gains better publicity, which brings more students.... and more money.",
"I'd just like to point out this phenomenon isn't US specific. It happens here in Finland even though we're said to have some of the best (mathematics) teachers in the world. (This is according to PISA studies.)\n\nWhat I've learned to do is look up all the things I'm expected to learn at [Khan Academy.](_URL_0_) They don't have anything on local diffeomorphisms, but everything up to that point I've found a clear explanation to!",
"Research both rakes in big $$$ for universities as well as builds the institution's esteem. Anyone with a Ph.D. (or even a Master's) can teach a class - you have to be super intelligent to conduct original, groundbreaking research.",
"Universities aren't about teaching, they're about *learning.* If you can look at it like that, it might help your frustration, if only a little.",
"When a faculty member at a research institution receives a $1million grant, typically about half that money goes directly to the University for \"services\", meaning the use of the facility, networks, computers, staff, etc. Now, the University was going to have to have all that stuff anyway, so this money is basically pure profit.\n\nFaculty who are really good teachers are generally so because they have worked hard to become so, often at the expense of generating a robust research/grant program.\n\nGiven this choice, major universities prefer the notorious researcher who brings in big money over the great teacher who brings in nothing.",
"Grants have a lot to do with it, but they're not the whole story. I used to work for the IT office at my university, and I had to sit in once when my boss gave a visiting professor a talk about how any research she did while at the university was partially owned by the university and they would be entitled to a portion of any future profits. It's not a big deal with someone like her (she was just publishing a book, which I think is a raw deal, since she had done most of the research before getting there), but it can get the university huge sums of money from STEM professors. \n\nOne of the professors in the engineering school won a patent infringement suit my sophomore year, and the university made something like $100 million since he filed the patent while working there. If he'd spent his time teaching instead of researching and filing patents, then he wouldn't have been worth anywhere near as much to the university than he was.",
"research makes crap loads more money",
"Research makes money and gets recognition. ",
"While this doesn't directly address your question, there are some benefits of having universities focus a significant amount of resources on research. For a specific example from a medical science perspective, pharmaceutical companies may develop vaccines in later stages, but much of the initial research is usually done by universities. It's simply not profitable for companies to do initial vaccine research, while universities have the resources and manpower to do this basic work. Of course this doesn't apply to all universities equally, but for the larger ones this is a benefit provided by university research as opposed to primarily teaching.",
"I'm currently faculty in a non-research university. I'm working on a Ph.D at a research university. And I just finished a prior responsibility of advising students at a 2 year college into our university. Hopefully I can give you some insights.\n\n* Non-research universities do focus on teaching. Sometimes quite heavily. Our faculty makes communication and the ability to teach the most weighted criteria in evaluating new hires. Can't speak comprehendible English? We won't consider them. Spent all their time writing research papers instead of applying knowledge? We also won't consider them. Also, every class of ours has evaluations, and we take them very seriously. Getting tenure and promotions after tenure require high scores in evals. \n* We focus on practical applications of knowledge. As a result, I can say without any reservation I'd hire our students over research university students for most jobs.\n* We're a public university, and so we don't make that much money. Most of us are here because we love teaching. The benefits are also awesome. We get to stay home 6-20 weeks a year, but our salaries are far below market wage. We struggle to get high quality new faculty because of this bind, but we do manage.\n* Research institutions focus everything on publishing, research, and developing new knowledge. These are the bleeding edge theorists. No focus on business applications or the workplace. Students are trained from beginning to end on how to conduct research and write research papers. There's also big money involved here. It's assumed at such institutions that the ability to teach doesn't matter. Students need to teach themselves. TAs free the faculty from having to teach students, so they can spend more time writing papers and applying for grants. Many of them also make twice in salary what we make, and they only need to teach one course a semester.\n* Some research institutions have research only professors. They don't teach a thing. They're busy applying for more grants and publishing even more papers. It seems the only reason research universities even have their professors teach is to recruit help in writing more papers. \n* Two year colleges focus heavily on quick and dirty business skills for all walks of life. The pay also is terrible. Instructors frequently take on 8 courses a semester to try to make ends meet, and each course suffers as a result. Most reasonable people find better ways to make money than teach there. So you often get some pretty poor instructors here.",
"Guess which one makes them more money, and gains better publicity, which brings more students.... and more money.",
"I'd just like to point out this phenomenon isn't US specific. It happens here in Finland even though we're said to have some of the best (mathematics) teachers in the world. (This is according to PISA studies.)\n\nWhat I've learned to do is look up all the things I'm expected to learn at [Khan Academy.](_URL_0_) They don't have anything on local diffeomorphisms, but everything up to that point I've found a clear explanation to!",
"Research both rakes in big $$$ for universities as well as builds the institution's esteem. Anyone with a Ph.D. (or even a Master's) can teach a class - you have to be super intelligent to conduct original, groundbreaking research.",
"Universities aren't about teaching, they're about *learning.* If you can look at it like that, it might help your frustration, if only a little.",
"When a faculty member at a research institution receives a $1million grant, typically about half that money goes directly to the University for \"services\", meaning the use of the facility, networks, computers, staff, etc. Now, the University was going to have to have all that stuff anyway, so this money is basically pure profit.\n\nFaculty who are really good teachers are generally so because they have worked hard to become so, often at the expense of generating a robust research/grant program.\n\nGiven this choice, major universities prefer the notorious researcher who brings in big money over the great teacher who brings in nothing.",
"Grants have a lot to do with it, but they're not the whole story. I used to work for the IT office at my university, and I had to sit in once when my boss gave a visiting professor a talk about how any research she did while at the university was partially owned by the university and they would be entitled to a portion of any future profits. It's not a big deal with someone like her (she was just publishing a book, which I think is a raw deal, since she had done most of the research before getting there), but it can get the university huge sums of money from STEM professors. \n\nOne of the professors in the engineering school won a patent infringement suit my sophomore year, and the university made something like $100 million since he filed the patent while working there. If he'd spent his time teaching instead of researching and filing patents, then he wouldn't have been worth anywhere near as much to the university than he was.",
"research makes crap loads more money",
"Research makes money and gets recognition. ",
"While this doesn't directly address your question, there are some benefits of having universities focus a significant amount of resources on research. For a specific example from a medical science perspective, pharmaceutical companies may develop vaccines in later stages, but much of the initial research is usually done by universities. It's simply not profitable for companies to do initial vaccine research, while universities have the resources and manpower to do this basic work. Of course this doesn't apply to all universities equally, but for the larger ones this is a benefit provided by university research as opposed to primarily teaching.",
"I'm currently faculty in a non-research university. I'm working on a Ph.D at a research university. And I just finished a prior responsibility of advising students at a 2 year college into our university. Hopefully I can give you some insights.\n\n* Non-research universities do focus on teaching. Sometimes quite heavily. Our faculty makes communication and the ability to teach the most weighted criteria in evaluating new hires. Can't speak comprehendible English? We won't consider them. Spent all their time writing research papers instead of applying knowledge? We also won't consider them. Also, every class of ours has evaluations, and we take them very seriously. Getting tenure and promotions after tenure require high scores in evals. \n* We focus on practical applications of knowledge. As a result, I can say without any reservation I'd hire our students over research university students for most jobs.\n* We're a public university, and so we don't make that much money. Most of us are here because we love teaching. The benefits are also awesome. We get to stay home 6-20 weeks a year, but our salaries are far below market wage. We struggle to get high quality new faculty because of this bind, but we do manage.\n* Research institutions focus everything on publishing, research, and developing new knowledge. These are the bleeding edge theorists. No focus on business applications or the workplace. Students are trained from beginning to end on how to conduct research and write research papers. There's also big money involved here. It's assumed at such institutions that the ability to teach doesn't matter. Students need to teach themselves. TAs free the faculty from having to teach students, so they can spend more time writing papers and applying for grants. Many of them also make twice in salary what we make, and they only need to teach one course a semester.\n* Some research institutions have research only professors. They don't teach a thing. They're busy applying for more grants and publishing even more papers. It seems the only reason research universities even have their professors teach is to recruit help in writing more papers. \n* Two year colleges focus heavily on quick and dirty business skills for all walks of life. The pay also is terrible. Instructors frequently take on 8 courses a semester to try to make ends meet, and each course suffers as a result. Most reasonable people find better ways to make money than teach there. So you often get some pretty poor instructors here."
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462xjo | how can ed sheeran's song "thinking out loud" win song of the year at the grammys when it wasn't released in 2015? | "Thinking out Loud" was released in May of 2014. How does it still qualify to be the song of the year at the 2016 Grammys? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/462xjo/eli5_how_can_ed_sheerans_song_thinking_out_loud/ | {
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"\"Uptown Funk\" was also released in 2014. Grammy nominations do not run the calendar year. For a song/artist/album, etc. to qualify for a Grammy for 2015, presented in 2016, it must be released between Oct. 1, 2014 and Sept. 30, 2015.",
"[This thread](_URL_0_?) gives an explanation.\n\nHint: Searches often help."
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2499zu | why do auctioneers still use "auction chants"? |
I love television shows like "Storage Wars" "Loud N' Fast" and the likes. While the shows are typically tacky, some of the knowledge gained from the shows and the rare items are pretty neat. One thing that really drives me crazy are the auctioneers. I don't understand why they still use "auction chants". I understand that it is to create hype and a sense of urgency, but it's 2014. Wouldn't a screen with a timer, or flashy animation create more hype and urgency ? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2499zu/eli5_why_do_auctioneers_still_use_auction_chants/ | {
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"3 reasons:\n\n1. because most auctions are small events that are fairly bare bone affairs. an auction company comes in, sells a bunch of stuff, gets a commission, and leaves. usually there isn't any extra room or time to deal with flashy items.\n\n2. if the auctioneer has a ringman (or ringmen at larger auctions) its a way for the auctioneer to communicate the ringman about how far away a bidder is from the reserve price or other instructions. the auctioneer and ringman share alot of back and forth information in plain sight.\n\n3. for a flashy sign to be effective, you have to be looking at it. you can usually hear the auctioneer chant for long distances. that way you are constantly hearing the rhythm no matter what you're doing or where your looking. keeping a constant, driving rhythm helps make people want to keep the action going, no one wants to be the guy that ruins all the excitement."
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3tjybt | if the middle east is seemingly so rich with oil, why is there so much poverty and civil unrest? | Or there is no significant amount of oil to be found in Syria et. al? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/3tjybt/eli5_if_the_middle_east_is_seemingly_so_rich_with/ | {
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"Because the governments of most Middle Eastern states are totalitarian and embezzle all that money away into Swiss bank accounts long before it ever reaches the people. In the case of Saudi Arabia and Iran they then use the money in those accounts to fund and export their particular flavor of insane fundamentalist religion and foment civil unrest in their neighbors.",
"Money from natural ressources are rarely split evenly across everybody (Norway for example, is doing something for their people with their oil money) and when the country or region is (made) unstable there is a fair chance of some people exploiting the riches of the country to hold on to this money for themself. You can also see that in many african countries, a single source of wealth that isn't in need of a functioning infrastructure, just somebody who digs up the oil and sells it is always a bad omen for poor people in the area.",
"This is not really specific to the middle east as there are quite a few variables at play, but generally speaking large natural resources tend to turn out badly for the country in question. This might seem like it goes against common sense, but there are legitimate reasons for this.\n\nIn many cases the countries that find large natural resources are developing countries with lacking institutions. In other words they don't have a proper mechanism to transfer the wealth to the general public or proper means to protect the assets. Combine this with general incompetence and you have the ingredients for a real shitstorm. The new money then starts attracting vultures both domestic and foreign, and suddenly all types of splinter groups start getting funds. The interests of the rich and powerful are usually more succesful than the interests of the general populace, so the people who ultimately end up in charge are mostly concerned with getting filthy rich themselves rather than building schools. \n\nIn more ways than one natural resources are like winning the lottery. It seems great but in most cases it ends in tears. \n\n"
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8x2eln | why does putting a band-aid on a minor wound cause it to hurt slightly less, even if it’s not open and bleeding? | Is it cushioning? Is it protection from drafts? Placebo effect? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/8x2eln/eli5_why_does_putting_a_bandaid_on_a_minor_wound/ | {
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"It stops the skin stretching die to the numerous microtears in the skin created the resulting wound. You may not be able to see it but the skin becomes more stretchy and delicate as a result of this. By having a bandaid you keep the wound in place and stop friction and movement which are things which cause pain."
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1ur5jd | does stretching after a workout really do anything regarding muscle soreness the next day? | The other day I read something here about stretching at it was said that stretching is entirely a neurological process, basically what you're doing is just flexing the muscles. I had thought this before, because working out, you're creating micro tears in the tissue of your muscle, once the workout is over, "the damage is done", you can't undo it by stretching. Is it suggested to stretch after a workout because your muscles are thoroughly warmed up, and thus prevent future injuries possibly caused by lack of flexibility? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1ur5jd/eli5_does_stretching_after_a_workout_really_do/ | {
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"It also elongates the muscle.\n\n\n\"A long muscle is a strong muscle\"- Arnold szwahshdjHahshdjshshsjhaahhancjaager",
"Oh and since you were talking about DOMS, no, stretching doesn't help that. ",
"Absolutely. It releases lactic acid that builds up in your muscles during a workout, which in turn allows you to have a greater range of motion and be less sore.\n\nWhen you exercise (and especially when you lift weights), you are tearing the fibers in your muscles and they are regrowing to be stronger. That is what strengthening your muscles *is*. Stretching is important for that.\n\nAnd take it from someone (me, or anyone else) who runs 35 miles a week and lifts weights-- stretching makes you feel better the next day. This is a fact. If you don't stretch, you will be sore the next day. Anybody here who is sitting in their chair and citing an article they found on google that suggests otherwise and believes it does not exercise.",
"The two views. \n\nYes : believed by most people and fitness professionals, also has some research to back it up. \n\nNo : fairly a new view, new researches have found out stretching did nothing, and may even bring harm. Static stretches is the main culprits in this."
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c0xwge | do insects have the same sort of internal organs as us? | Do they have brains and digestive systems etc? I can’t imagine them having a tiny little stomach or heart or anything, so how does it work? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/c0xwge/eli5_do_insects_have_the_same_sort_of_internal/ | {
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"No, they do not. They have analogous systems, but they can vary wildly in function. For example, the respiratory system of most insects is trachea, not lungs; they do not have a pump that hauls air to and fro, they absorb oxygen by diffusion.\n\nOnly vertebrates have truly the same organs as us, because they evolved from the same ancestors as us. Frogs, snakes, birds, cats and dogs and humans all come from the same primitive ancient lungfish which already had familiar internal organs. The arthropods split much earlier, at the worm stage that had barely any organs at all, and evolved independently."
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5z738o | how does flint, mi still not have clean water? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5z738o/eli5_how_does_flint_mi_still_not_have_clean_water/ | {
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"It's slowly improving. Water sources aren't exactly easy to clean up once they're contaminated, and replacing the lead pipes takes time (they've officially got another 2 years to complete the project).",
"For the same reason it got lead in it in the first place. The system is old, a replacement or significant update will cost a lot of money, and Flint doesn't have enough money.",
"You can't fix a city's entire water supply infrastructure over night. The system is underground, so even the parts that can be dug up are under streets and people's yards. Then there's the parts that run under buildings and such....\n\nNot to mention, it's been winter up there. The ground is frozen in winter, which adds that much more labor to the whole process.",
"The mistake that led to Flint's toxic water was a water purification error that corrupted the actual *pipes* the water flows through. So the water itself can be perfectly clean, and on the way to your house, the pipes will leech toxic amounts of lead into it.\n\nIn order for Flint to repair its water problem, it has to replace all of the pipes in the city. This is really expensive and Flint doesn't have the money to do it. Most cities wouldn't have the money to do it, as they only budget for a certain percentage of pipes to be replaced and serviced every year.\n\nThe replacement cost has been estimated to be $60M and the project, to be fully completed, to take 15 years. There are about 29,000 pipes that need to be completed. They are focusing on the most at-risk homes first and several hundred have been completed.\n\n",
"They have yet to replace every single pipe in the entire city. All of them have to be dug up and removed from the streets and houses and replaced. That is extremely expensive. ",
"Not necessarily an answer to this question but I wanted to chime in.\n\nI was born and raised in Flint Town. Mom worked downtown at UM Flint and I went there for a few years.\n\nAs far back as the 90s she would say that everyone in her office, at Water Street Pavillon, knew they were pulling water from the river. They stopped drinking it and making coffee with it. Several of the restaurants in the pavilion did too. The ones who didn't you could tell. Their pop/soda tasted like shit.\n\nWhenever I would drink from a fountain on campus (we're talking back in like 01-03) it tasted absolutely god awful and had a yellow tint to it. Kind of tasted like dry wall.\n\nI said all of that to say this - this wasn't a new problem.\n\nIt fit into a media cycle because the story was so bombastic and the state government made the choice to switch the city as a whole to that water only a few years ago. However, several places in Flint have been on that water since I was a kid.\n\nWe have always known that river was disgusting. No one ever wanted to get in it. We didn't really have any river-related activities in Flint that many people participated in. No one fished in it. No one swam in it.\n\nAs a matter of face, I remember when I was a kid and they drained a 1/4 mile portion of it. They pulled out several old cars, guns, knives, safe's, and other contraband. I think they even found human remains if I'm not mistaken.\n\nPoint being it's not like everything was fine in Flint and then BOOM all of the sudden the water is toxic. The river has always been shit and more and more businesses and municipalities have been getting their water from it to save money for years.\n\nThere should have been a clean up effort for the river LONG before this happened, and I mean 30-40 years ago. This river has been toxic and a danger since the first factory started draining their sludge into it a hundred years ago.",
"How did the entire infrastructure break down at the same time ? Did all the pipes corrode at the exact same time or what ? It feel as if simply overnight they went from usable water to water you cant drink. Im sure i am missing something here though.",
"Life long MI resident here.\n\nFlint knew this would be a problem way back in the '70's. They were supposed to replace the pipes back then. All that money got embezzadled. ",
"[This Old House has talked about this a time or two.](_URL_0_) It's the same as the top comments here. But with visuals.",
"uhm eli5, Why isn't the clean-up federally funded?",
"I live in Flint, I've had my water tested, it's fine but, we don't drink it or cook with it. I would love to just move but houses near me go for like 5 grand and I can't afford to sell my house for that. So many other cities across the Nation are finding out their water contains heavy metals and other contaminants. Until infrastructure is addressed on a massive national scale more and more community's will suffer the same fate as Flint. Once it happens to a more affluent, less urban area maybe then, we'll see a plan on how it can be fixed."
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fn2lst | how does gene diversity develop if we all came from common ancestors? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/fn2lst/eli5_how_does_gene_diversity_develop_if_we_all/ | {
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"Mutations. Genes change. Your genes aren't exactly duplicated from your parents. The differences are slight, but given many generations they really do build up.",
"Just to add onto the other answers, a slight mutation rate is actually built into us. It's *possible* to make proteins (DNA polymerases) that are more accurate at replicating our DNA, but we don't actually have them because some amount of diversity is good.\n\nFor a real-life example, the influenza virus has a relatively inaccurate polymerase, which causes lots more mutations, which is why it's hard to make a perfect flu vaccine."
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2yk4m7 | how does " save game " and "load / continue " work? | I know maybe stupid question but, i'm wondering ages about how it's works. Saving games with F5 and Load with F9 ( Usually same combination for most games.) What's happening in the background? And why doesn't work for other games like GTA or CoD. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2yk4m7/eli5_how_does_save_game_and_load_continue_work/ | {
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"Short Explanation: The game runs a chunk of code which pulls a bunch of data currently stored in the computers RAM, (it's storage space for the memory it's currently dealing with) and records it to a hard drive for permanent storage.\n\nDetails: The reason it doesn't always act the same is that it doesn't always make sense to store ALL of the data the program is storing temporarily. For a huge game like GTA or CoD there are a TON of things being stored temporarily, the current amount of dust floating in the air, the trajectory of every bullet, the location, duration and volume of the currently playing sound effects, the size, amount and angle of all the bullet holes in every surface, the location of every dead body, the position of every dead body, the footprints in the sand, (and for GTA) the location, driver, condition, direction and angle of every vehicle everywhere, the current animation, position, and speech for every single pedestrian.\n\nThat's a TON of data, and that's why these games might be using multiple Gigabytes of your ram as you're playing them. So when you go to save the game picks a subset of that data and stores it. In GTA it'll save your progression, your weapons/ammo your health and your location, probably also the day/time and the stock market info. It'll also save cars parked in specific locations. That's a TINY amount of data in comparison, and so it's easy to save.\n\nThe problem is you can't easily save and re-load from anywhere because all of that extra data isn't stored. If you could quick-save in a car and quick-load back, the game would have to store gigabytes of storage and pull it back out fast if you wanted to be able to revert to just before that big jump or just after you swerved past that police car.\n\nIf you have a simple game there is much less data involved and so it's easy for the game to save everything and retrieve everything immediately, allowing you to revert back to a specific instant. This is also how emulators do save-states. The save state stores every bit of data in temporary memory, and then shoves it all back in when you load, continuing where you left off.",
"To save a game, the game simply notes the exact position, health, speed, equipment, etc of everything in the game that can move or change. It saves all this in a file. Then, when you load the game, it reads all this information from that file and puts all the characters, cars, computer characters or whatever back where they were.\n\nAs for why it doesn't work in some games - that's entirely up to the games designer to decide."
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ea45ts | if you were to breathe in extremely humid air, for long periods of time, would you eventually ‘drown’? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/ea45ts/eli5_if_you_were_to_breathe_in_extremely_humid/ | {
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"You could potentially, if your lungs were colder than the ambient temperature, which would allow the water vapor to condense down back into a liquid form rapidly enough to prevent the lungs from expelling them through normal processes. It could also occur under different atmospheric pressures than are generally found on Earth."
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4bdnrx | why do millionaires only have a small percentage of their wealth in cash or liquid assets? | A multimillionaire may be worth several million dollars but I looked at some examples of celebrity net worth online and found that a person worth $40 million only has $50,000 in spendable cash.
I used to be under the impression that millionaires have literally at least a million in cash to spend. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4bdnrx/eli5_why_do_millionaires_only_have_a_small/ | {
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"Cash and liquid assets don't make you any money. If you invest your wealth, it can make you more money, but it's not in a form that you can immediately spend.\n\nI wouldn't have a million in cash on hand unless I had an immediate need to spend a million dollars on something.",
"You're net-worth is a combination of all your assets. If you own a business, or your fame is an asset, then it has value . However, converting this to cash can be difficult and results in saying things like \"a millionaire on paper\". If I were to loan you $1M of my $1.01M in cash, my net-worth would still include the $1.01M because I have an asset which is my loan to you. But...needless to say, you have that $1M and so I can't go out and spend that $1M.",
"A millionaire is someone who has a million dollars in net assets, house, retirement, businesses, etc. There are a lot of middle class millionaires out there.\n\nWealthy people don't need a lot of liquid assets, because they have easy access to credit. If they want to buy a $200K car, they take out a loan, and because they have good credit, they don't pay much interest.\n\nThat way they can keep their money in investments and businesses where it will keep working for them.",
"When people think of millionaires they tend to have the wrong image. Many upper middle class people are millionaires, and probably make up the largest percentage of millionaires. These people tend to have 1 mill to 3 mill in assets, and slowly grew their wealth through mostly equity in their home and 401k and other small properties they've invested in. Even these types of people dont have tons of cash on to spend"
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2mpa9g | why are retainers needed after braces? | I was wondering how come after we get our braces off, our teeth don't just stay in position and we need to have retainers for the rest of our lives to keep them straight. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2mpa9g/eli5why_are_retainers_needed_after_braces/ | {
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"It's because your gums are no longer as resilient as they were before. You move all your teeth by pushing and pulling them where you want them, the gums lose their strength slightly.\nImagine pouring concrete, you need a frame to pour it into, until it hardens, so it'll maintain shape on it's own."
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2ljfgh | dreaming for people who were born blind. | How does someone who has never experienced visual stimuli their entire lives dream? Is it in sounds, feelings, textures, the shapes of things they've experienced through touch? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2ljfgh/eli5_dreaming_for_people_who_were_born_blind/ | {
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"I have always wondered about not only dreaming, but visualizations in general for those who are born blind. Can anyone shed some light on this(omg terrible play on words but I'm keeping it)? When they picture an object can they spatially picture it in their head through experience through touch? \n\nCan they visualize in color but simply can't correlate their colors to what we call red and blue?",
"I work for a state school forr the Blind. All of the students that have been blind from birth say that they just dream in sound. Same goes for the deaf community. They just dream in pictures and no sound. ",
"Based on what I've read in this post and on several blogs:\nPeople's dreams are all based on past experiences, none of which are entirely original.\nWhich brings up an interesting point, how torturous must it be to regain sight only when your eyes are closed.\nThat's some poetry shit right there ^"
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47tsib | why is satanism commonly connected to occultism? | They seem to be portrayed as almost synonymous. I've also read the 11 Laws, with one of them mentioning magic. Is magic and Occultism prevalent in the religion? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/47tsib/eli5_why_is_satanism_commonly_connected_to/ | {
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"Theres a huge difference between the different types of satanism. \n\nThere's LeVeyan satanism which is the stuff you hear about a lot. The 11 rules are a part of that. [here](_URL_0_) is a lot more about them, they less literally worship satan and more base around the golden rule philosophy. LeVeyan satanism actually denies that a being like satan or god could exist. \n\nThe other type of satanism is literally worshipping satan, which is very closely linked to the occult and only really practiced by crazy people. "
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9al734 | how does an electric current produce a magnetic field? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/9al734/eli5_how_does_an_electric_current_produce_a/ | {
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"The short super unsatisfactory answer is that it just does.\n\nThe longer answer is that what we define as a charge is actually a disturbance in the electric field, which is part of the electromagnetic field. A moving charge creates a disturbance in both the electric and magnetic field. The two phenomenons are intertwined. So its less that a current creates a magnetic field and more that a current and a disturbance in the magnetic field are part of the same thing. Its like asking why the crest of a sin wave creates a trough. They are intertwined to the point of one not being able to exist without the other. ",
"It's one of the fundamental laws of the universe. An electric current is the movement of charged particles. A charged particle creates an electric field. A changing electric field creates a magnetic field. So the moving charges are causing the electric field to change, and therefore a magnetic field is created.\n\nThe reverse is also true. A changing magnetic field causes a change in the electric field, which causes the charged particle to move - inducing current.",
"You are asking a very involved question. Moreover, it can be answered in several different but equivalent ways. All of the answers I see below are referencing Maxwell's Equations, which is a reasonable approach. However, they don't explain *why* the magnetic field is created - they only provide the method for calculating its direction and strength.\n\nWithout going into the details (because as I said it's very involved), I would direct you to study the relativistic phenomenon of length contraction. Length contraction is the direct physical cause of magnetic fields, and without it they would not exist.\n\nTo put it very bluntly, magnetic fields are actually electric fields under the influence of relativistic length contraction. That's why only moving charges produce magnetic fields.\n\nHope that helps.",
"You ever see a question and just KNOW the answer will make your brain hurt? This is one of those. \n\nAlso, anything about quantum mechanics or orbital physics. Get too far away from human sized, and stuff just acts WEIRD. "
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9o50u7 | how exactly does carbon-14 dating work? would it work on diamonds (which were once organic matter, i think), or are they just too old? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/9o50u7/eli5_how_exactly_does_carbon14_dating_work_would/ | {
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"Carbon-14 dating is primarily for dating formerly living things. Carbon 14 is made in the atmosphere so its absorbed by living things through respiration. It maintains its levels while the thing is alive. When it dies the respiration stops replenishing the carbon so it starts to decay away since carbon 14 is radioactive. So you know the level in the environment and the level in the formerly living thing and the decay rate of carbon 14. So this tells you how old it is.\n\nBut the half life of c14 is 5000 years so it cant date anything older than 50000 years because theres no c14 left and it cant date anything less than 200 years old because we ruined the c14 levels in the atmosphere with the industrial revolution.",
"Chemistry is governed primarily by electrons, which are in turn largely affected by the number of protons in an atom's nucleus. What this means is that if you have an atom with 6 protons and 8 neutrons it'll have almost exactly the same chemical properties as an atom with 6 protons and 6 neutrons. That's why we identify elements in terms of their proton count; both of these atoms would be called Carbon.\n\nNot all proton and neutron counts are created equal. If you get too many or too few neutrons then the nucleus winds up unstable. Sometimes this instability is only slight and an atom can exist for thousands or even millions of years on average before it breaks down. Sometimes it's so severe that the atom will decay in a matter of nanoseconds.\n\nIn the upper atmosphere on Earth the rays from the sun cause a number of interesting nuclear reactions to occur. One of these creates C-14 (6 protons, 8 neutrons). C-14 decays in a few thousand years on average. Earth is billions of years old and the atmosphere and sun don't change that much or that fast, so the amount of C-14 in the atmosphere remains fairly constant.\n\nAs living things go about their lives they acquire carbon. First plants pull it from the air for use in photosynthesis, then that carbon is transferred to herbivores, then to carnivores, to decomposers, and so on. When plants pull carbon from the atmosphere they do so based on carbon's *chemical* properties, not its *nuclear* properties, so this carbon will have the same ratio of C-14 to C-12 as is in the air.\n\nWhen a living thing dies it stops carrying out its life processes that would chemically select carbon. However, the decay of carbon over thousands of years still caries on. When a scientist analyzes the long-dead lifeform they can start by making the assumption that the life form's carbon ratio was equal to the atmosphere's C-12 to C-14 ratio, then compare that to the ratio that the life form has today. They do some math and determine how long ago the chemical processes must have come to an end (i.e. how long ago the life form died).\n\nThis process with Carbon is only usable for things about 50,000 years old and younger. Diamonds are far older than this, so we just don't have tools precise enough to accurately determine the diamond's age. There are similar methods that use other chemical elements that have longer lifespans which may be used to date older items. This wouldn't be useful for diamonds as they are pure carbon. "
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ezocfs | why do appliance's volumes (eg. tv, radio) use an arbitrary 1 to x value instead of basing the value on decibels? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/ezocfs/eli5_why_do_appliances_volumes_eg_tv_radio_use_an/ | {
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"High-end stereos for audiophiles, or studio monitors, typically do use decibels.\n\nThe problem with decibels is that either you'd have relative loudness - where 0 is the maximum and anything softer is a negative number - or you'd have absolute loudness, in which case headphones would only go up to some small number and your stereo would go up to some other number. It'd be confusing for most people either way.",
"If you run your signal through different amplifiers and speakers, the db markings become meaningless. The arbitrary numbers make more sense. \n\nPlus db isn't a linear thing relative to how you hear and experience loudness and the controls themselves are non linear. So to accurately mark off db levels might result in unevenly spaced markings.",
"Because dB measure relative loudness and work on a logarithmic scale. Try getting your average consumer to understand what that is and how it works. It's time consuming and completely unnecessary for setting a desired volume on a TV or radio. It's much simpler and easier to use for consumers to just have linear number going from 0 or 1 to whatever.",
"Because if they used dB, the vast majority of consumers don't really know what decibels are and would be confused by 0 being maximum volume. Typical users only care about \"louder\" and \"quieter\" and are perfectly happy with arbitrary volume scales."
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43hrlg | what is all this controversy with thefinebros about? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/43hrlg/eli5_what_is_all_this_controversy_with/ | {
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"Search before submitting "
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338naj | are wi-fi and/or bluetooth, signals harmful to our health? | I'm sure this can be researched online, but I've often wondered how much information is actually true. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/338naj/eli5_are_wifi_andor_bluetooth_signals_harmful_to/ | {
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"text": [
"No, it's not true at all. They're completely harmless. ",
"There has been numerous studies, and the concensus is that radio signals in the WiFi and BT bands are not harmful at the levels output by communication devices. ",
"The radiation our WiFi hotspots and cell phones emit isn't strong enough to damage cells, so in theory it should be safe. But also, billions of people have been subjected to those signals daily for decades and no increases in any diseases have occurred.\n\nIt's pretty impossible to prove that they can't be harmful in any way, but it's pretty clear that if it was something really harmful or life-threatening, we would have already seen it.\n\nI wouldn't worry."
]
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[],
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6q24xd | seeing all of these harambe & deez nuts votes in the presidental elections, what would happen if one of them actually got the majority of the votes? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/6q24xd/eli5_seeing_all_of_these_harambe_deez_nuts_votes/ | {
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"Harambe is not human, and is deceased so does not qualify. All votes to him are void. \n\nDeez Nuts is not the real name of the child, and they are under 35 and so not eligible. All votes to him are also void. \n\nSo the electors for that State would give their vote to the eligible candidate with the most votes. ",
"If the person behind the name *was* eligible, then he or she could get the job. In the last election in the UK, Lord Buckethead stood against Prime Minister Theresa May in her constituency: if he had one, she would have lost the PM job (since the PM has to be a MP), and he would have become an MP. "
]
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[],
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||
2b1gcb | why do i find baby animals super cute, but human babies ugly? | A lot of people are like me and just love puppies, kittens, baby elephants, baby groundhogs, baby anything. But, there's a big consensus that babies don't look very nice. Is there a scientifical explanation behind this? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2b1gcb/eli5_why_do_i_find_baby_animals_super_cute_but/ | {
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"text": [
"Because baby animals are cute and human babies are ugly.",
"A lot of what makes things cute is the ratio of eye size to facial real estate. Many young animals have a better ratio than humans in this regard. In other words, the animals literally have \"puppy dog eyes\".",
"You're looking at them at different times of development. Eight month old babies can be adorable, as can 6 week old puppies. But newborns and 1 week old puppies look like worms with legs. ",
"haha, I wanted to do the same question recently, im pretty sure that is because the fur every animal is not that cute without it"
]
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3ro4uz | how is it that mars has lost it's atmosphere to solar winds, but earth hasn't | Like it says in the title, how are they losing their atmosphere to solar winds, but earth isn't? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/3ro4uz/eli5_how_is_it_that_mars_has_lost_its_atmosphere/ | {
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"The churning of earth's core creates our magnetosphere which protects us from the solar winds, it's like a shield protecting us from the sun's \"bullets\" (charged particles). The stronger the core churns, the stronger the magnetic field or shield. Mars' core is dead or dying, so it no longer has a strong magnetosphere to protect its atmosphere from the solar winds (\"bullets\"). So every blast just kept chipping away at it until it was gone.",
"We have a magnetic field produced by a dynamo action in the interior of the Earth. Mars is though to have lost this. The magnetic field helps deflect the charged particles from the solar wind that would otherwise strip the atmosphere away. ",
"Earth's magnetic field [protects](_URL_0_) its atmosphere by deflecting the charged particles of the solar wind.\n\nMars doesn't have such a magnetic field.",
"The answers so far a true as far as they go (and deserve upvotes). Mars has little to no magnetic field to repel the Sun's charged particles so its atmosphere is \"blown\" away. Mars has less gravity than Earth so it holds all things, including atmosphere, less tightly.\n\nIn addition, since Mars is so much smaller, it outgassed less than Earth. It also captured less of the gases that were floating around the early solar system. As such, its atmosphere was probably never anywhere near as dense as Earth's even in its heyday.\n\nFinally, because Mars is so much smaller than Earth, it cooled much faster. Mars cooled to the point where an atmosphere could form as many as a billion (with a B) years before Earth, so Mars has had a lot longer to lose its atmosphere than Earth has."
]
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[],
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"https://en.wikipedia.org/wiki/Solar_wind#Magnetospheres"
],
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eqm5bf | why do lemons sometimes become all green and moldy, while other times they become rock-hard when you forget to eat/use them? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/eqm5bf/eli5_why_do_lemons_sometimes_become_all_green_and/ | {
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"Depends on the environment. It's the same as why some bread will just go hard and stale while other will grow moldy.\n\nA good experiment is getting a new pack of sliced bread and taking the first slice with some gloves on and putting it into a new bag. Then take another slice with bare hands and touch it all over before putting it into a bag. After a couple days to a week, you'll find the one you took out with gloves on to be mostly fine if stale. While the one you didn't use gloves for, will likely have mold all over.",
"If the fruit/food/meat dries out faster than bacteria/mold/fungus can replicate, then you just end up with a dried up husk or jerky. No matter the food, once the moisture content is low enough nothing will grow on it.\n\nSo that usually means items in areas of high airflow will end up in the hard state, whereas those in enclosed spaces or humid areas will end up in the spoiled/rotted state."
]
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[],
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||
c7re9o | why aren't tv shows that follow criminals, like drug smugglers, forced to hand over footage? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/c7re9o/eli5_why_arent_tv_shows_that_follow_criminals/ | {
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"Aren't they \"handing it over\" by publicizing it?",
"It really depends on the ethics of the filmmaker / journalist. I know in the States we have the Freedom of the Press. This allows Filmmakers and journalists to report on certain topics without persecution. Now this doesn't mean that they cannot be charged with obstruction of Justice for withholding evidence. At that point it's a matter of how much money you have, how good your lawyer is and how strong your ethics are. As a journalist if your source wants to remain nameless it is your duty to keep your source confidential. Prosecutors can get a court order saying you have to give up your source if it is a matter of national security (Thank you Patriot Act) but again what are your ethics. There are multiple journalist who have been charged especially under Nixon, and Trump. What normally happens is if they can't charge you with anything the IRS tends to Audit you, and everyone around you. The government will make your life hell until you play ball. This is all if the show isn't staged, but having worked on a few they mostly are....",
"Forcing journalists to reveal their sources, you mean? \nThat's not a path many civilised countries are willing to go down just to bust a small-time drug dealer."
]
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[],
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||
4sjztk | how long does a fly have to spend on your food before it has done anything that may pose any sort of health risk? | By "done anything" I mean, for example, the vomiting that the fly must do as part of its eating process. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4sjztk/eli5_how_long_does_a_fly_have_to_spend_on_your/ | {
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"The length of time he's on food has little to do with it. What matters is what is on the fly, and if it gets on the food. There really is no way to predict it. A fly walks around on shit a lot and can potentially carry things like salmonella and e-coli. In general, the risk of a single fly landing on your food is very, very low.",
"The analogy I always use to debunk any kind of \"five second rule\" type of thinking is a person with fingerpaint on their hands. If they touch something, a bulk amount of the sticky substance transfers to the surface the very instant that they make contact. There isn't a minimum amount of time that the paint-covered fingers have to remain in contact with that surface. If something gets touched, it's getting some non-zero amount of paint on it.\n\nThat's how cross-contamination works, too. Don't think of it in terms of the fly vomiting or breathing, or any kind of migration of bacteria somehow taking time to \"walk\" across from the contaminating object onto the clean surface, or any kind of other slow process like diffusion. The transfer is actually done when a small (could be microscopic) but still *bulk* amount of material breaks away from the contaminating object and adheres to the clean surface. If undesirable bacteria (or other dangerous substances) are present within the adhered material, then contamination has happened. "
]
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[],
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fyjint | where did the idea of bears being cuddly and lovable and the idea of teddy bears in pop culture come from l, and why did we pick a animal that's a killing machine to give this image to? | I was also asking where the idea of the actual animal being friendly and cartoony came from | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/fyjint/eli5_where_did_the_idea_of_bears_being_cuddly_and/ | {
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"The \"Teddy Bear\" was created after Teddy Roosevelt went on a bear hunt that went nowhere. Trappers brought him a caged bear as a trophy instead, but Ted said that was too unsportsmanlike (although the injured bear was put down anyway).\n\nThe story spread and novelty stuffed bears became popular toys during his administration.",
"President Theodore Roosevelt once became the subject of controversy for refusing to shoot a tied up bear during a hunting expedition considering it unsportsmanlike.\n\nTeddy was his nickname, although he loathed being referred to as such.\n\nThis story resulted in the creation of various political cartoons depicting the stoic picture of the President and \"Teddy's bear\". Although the actual bear was an adult the cartoons portrayed the bear as a cute cub.\n\nA number of companies began producing cute Teddy Bear toys as a result. Roosevelt loved the idea and adopted the stuffed bears as his mascot, and they've since become extremely popular children's toys.",
"Well, I have three of nature’s most ultra efficient killing-machines asleep in various parts of my house right now.\n\nThey are called cats.\n\nBut I agree with your point.\n\nStill, doesn’t popular culture eventually make every type of animal into a cutesy version of itself?",
"Cartoons plus the human tendency to anthropomorphize everything? \n\nThe US Forest Service changed the image of Smokey The Bear in the 1970s or 1980s to make it seem meaner and scarier, in an effort to keep people from trying to play with wild bears they encountered in the national parks. Actually that had already been done in the 1950s, maybe for the same reason."
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5bag4q | how come when a neutron star spins incredibly fast, it creates radio jets and becomes a pulsar? | On the same note, are there neutron stars that spin rapidly just like a pulsar but just don't have their radio jets? If that's the case, then how does a pulsar obtain it's radio jets? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5bag4q/eli5_how_come_when_a_neutron_star_spins/ | {
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"text": [
"Every neutron star spins rapidly and produces radio jets. This is because as the star gets compacted down it has to maintain its angular momentum, the same way a dancer brings their arms in to spin faster. The radio jets come from the fact that you have a lot of mass spinning very very fast, which produces very strong magnetic fields.\n\n However, not all neutron stars will have their jets pass over the earth as it spins/wobbles. The ones that do are what we call pulsars(blazers if they're pointed directly at us)."
]
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[]
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|
6to388 | why do other countries (outside of the us) have little or no commercial breaks on tv? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/6to388/eli5_why_do_other_countries_outside_of_the_us/ | {
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"You may want to be more specific as many countries have just as many commercials on TV as the US does.",
"Turkey has 2 hour long shows with 1 hour advertisement. They usually take 7 to 10 minute breaks every 15 minutes. ",
"As an example, I believe England has their stations technically run by the government, kind of like PBS here\n\nThe US on the other hand leases out different bands to companies (nbc, cbs, etc) so they have to pay for their costs"
]
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[],
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||
4zarur | why does mold grow slower in colder temperatures? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4zarur/eli5_why_does_mold_grow_slower_in_colder/ | {
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"text": [
"Life is just chemical reactions. Chemical reactions either produce heat, or take heat from their surroundings.\n\nThe act of reproduction is lots and lots of chemical reactions, some of which need heat from the surrounding environment. If there's less heat in the environment (it's colder), those reactions go slower. The entire chain of reactions is thus slowed down, and so the growth is slowed down."
]
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[]
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||
34z70t | what functions do d3 and 2 have in automatic cars and what situations should i be using them? | Also, is there any fuel efficiency or hazardous weather uses for them? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/34z70t/eli5_what_functions_do_d3_and_2_have_in_automatic/ | {
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"Those are your \"low gears\". They're good for climbing steep grades, towing, and you can also use them as an \"engine brake\" when you're going down a steep hill so you don't have to hit your brakes as much and wear them out. "
]
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[]
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|
36bqcf | - how were roads built and paved before large machines were invented? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/36bqcf/eli5_how_were_roads_built_and_paved_before_large/ | {
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"Mostly by hand. They'd have [lots of people](_URL_1_) involved, though. Sometimes crews of hundreds or even thousands. \n\nEven today, with all the large machines, there are inaccessible places or places where there's no financial incentive or other means to pay for it where they have to do it by hand. (In one such place, a man [spent 22 years](_URL_0_) cutting a road through a mountain by himself with a hammer and chisel, because the hospital was in another town and going around took too long, and his wife died.) You just line the guys up and set to."
]
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"http://www.huffingtonpost.com/2015/03/24/this-man-cut-a-road-throu_n_6939898.html",
"http://i.imgur.com/oeX1c5p.jpg"
]
] |
||
6nvn4u | does celibacy contribute to increased proficiency and productivity? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/6nvn4u/eli5_does_celibacy_contribute_to_increased/ | {
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"ELI5 rules dictate that I can't just reply with \"no\" but if I could, I would. Yes, there were some notoriously brilliant people who were celibate, but there are millions of people out there in the world right now who are celibate (either by choice, or because nobody will have sex with them) with absolutely no great abilities or advantages, and there have been thousand of noted brilliant people who led very normal sex lives.\n\nConsider: Certain mental disorders cause a person to be very very brilliant at a specific subject, and very very remedial in other areas of their lives. It's much more statistically likely that Tesla and Newton had mental abnormalities that made them fantastic at math and science, but caused them to have very poor social skills, or no interest in sexual activity. \n\nThere are studies that suggest that for a man, going a few days without an orgasm can have a minor impact on some hormones in your system, notably testosterone, but there aren't any studies or stats suggesting that this has any meaningful impact on your mental clarity or abilities, and after a short while (7-10 days) things go back to normal as your body adjusts. "
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||
81dxx9 | the tariff war in 2002 and how the proposed 25% tariff for steel imports from canada will hurt the us economy | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/81dxx9/eli5_the_tariff_war_in_2002_and_how_the_proposed/ | {
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"This is argued every day with many viewpoints. This is ELI5. \n\nIf the leaders of a country want their industries to grow they impose tariffs, taxes on imported goods. That helps local companies produce these goods which means locals have jobs. Seems good.\n\nNow imagine taking this further. You want your town to have industry and locals to have jobs. Suppose the town could actually impose tariffs on all goods brought in. Tax the milk, the bread, everything. Now supposedly local people have jobs. But there is no dairy in town so you are just paying higher taxes. The local bakery owner is a drunk and does not bake good bread. But he is protected by the tariff and can continue drinking and baking bad bread.\n\nFurther the other towns, or countries, reacted to these tariffs by imposing and raising their own. Suddenly your producers have no market.\n\nFree traders say we do best with no tariffs. If something can be made very cheaply elsewhere, then imported, then we pay low prices. We specialize. They specialize. Prices for everyone are as low as possible.",
"In an open market whoever can spend the least amount of money per unit of goods produced has the competitive edge and can sell their goods at a lower price than someone else. The consumer gets the lowest price possible.\n\nNow if you introduce tariffs you are increasing the cost per unit of international goods which causes your domestic goods to be more favourable. Now the domestic goods are cheaper than the international ones. Problem is the overall cost of the goods to the consumers rise as well. \n\nSo sure you can make a few new jobs domestically but at a higher cost to everyone who consumes the goods.\n\nNow of course since it’s ELI5 that’s the simplistic case looking at only one commodity, in the real world the response to tariffs is usually more tariffs and embargos. That is, if the USA threatens to put tariffs on Canadian steel then Canadians can in return put tariffs on American products and buy less of them (or stop altogether). \n\nSo by trying to help the steel industry and create a few jobs the overall result hurts the steel consumers (essentially everyone) and overflows into potentially many other industries which rely on reciprocal trade agreements to sell their products."
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317z2z | how does someone live without a gallbladder? does it change how they eat? if so, how? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/317z2z/eli5_how_does_someone_live_without_a_gallbladder/ | {
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"I live just fine without a gall bladder. I have not changed my diet in the slightest.\n\nA gall bladder allows me to store bile, so that in theory, if I suddenly ate (say) an entire bucket of lard, I would have enough bile ready to digest it.\n\nInstead, I am now relegated to eating that lard in small spoonfuls evenly throughout the day, to ensure the availability of the bile I can no longer store."
]
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||
6z95ku | why do we have an easier time sorting things by strings of numbers vs by strings of letters? (ex: t#124567 vs t# asedtz) | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/6z95ku/eli5_why_do_we_have_an_easier_time_sorting_things/ | {
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"The order of numbers is meaningful, 2 comes before 7 for a reason. We are also used to counting up and counting down, which reinforces this order in our minds.\n\nThe order of letters is arbitrary, we could rearrange the alphabet and it wouldn't make much of a difference. There is nothing innate about K that makes it come before P, so it requires more mental effort to figure out their proper order."
]
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[]
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||
83u38z | if dna contains informations about our whole body, why can we not regenerate certain body parts if they gets removed? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/83u38z/eli5_if_dna_contains_informations_about_our_whole/ | {
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"IKEA instructions do not equal a finished IKEA cabinet :) similarly, if you build the cabinet you no longer have the materials to build another one, even though you still have the instructions. You need more materials (which, for humans, basically boils down to stem cells). \n\nThis isn’t perfectly 1 to 1, though. Most of the genetic information that our bodies utilize is for the internal processes on the cellular level to ensure that things run smoothly and you stay alive. The most marked development that we make, which is in the womb, is only possible because of the highly malleable nature of stem cells. Those stem cells change into different cells once we’re born and are spread all over our respective internal systems, thus limiting their uses. \n\nWhat I can’t answer, though, is why humans are unable to regenerate while other animals can. It’s definitely something that researchers are investigating, but there is no real concrete answer yet. The Darwinian explanation is that over the millions of years that those animals developed, evolution by natural selection ‘selected’ for traits that are most beneficial for that species’ survival. Evidently, humans did not need significant regeneration to survive! ",
"Big question under debate. There's evidence, though, that we do have the capability (ish). [Couple](_URL_1_) of [refs](_URL_0_), but there are lots out there with some googling.\n\n The genetic switches are just turned off, or we're missing a couple genes. Probably because at some point during a time of limited resources if there was a serious injury to the individual it made more sense (in terms of natural selection) to let the individual die rather than waste a bunch of resources on something as expensive as regrowing a limb. Better for the population to save local resources for individuals not missing a leg.\n\nIf we don't go as extreme as dying and instead assume that the regeneration is for smaller body parts, it would still be incredibly taxing and energetically expensive (need lots of food, minerals, etc.) to regrow that body part. If it was something non-essential like a finger, again at a time of limited resources, then it might be an advantage to dedicate what little food you have on more essential body functions then regeneration of a ring finger.\n\nThe 'why' is of course just speculation.",
"The DNA contains instructions as to how to create a baby from a single cell, by telling what cells to specialise in. However those instructions don't work once the assembly has been completed. To reassemble a whole limb say it would take a lot of energy and time as it would have to be slowly assembled from the remaining stump. During this time the limb would not help you survive and due to the drain on resources would actually reduced your survival chances. Therefore in an evolutionary sense it isn't worth it, if you survived the injury that caused it you can survive without it.",
"Building the human body like an automated car production line. We just haven’t worked out how to force our DNA blue print to “repeat that one part” again. \nEven though every cell carries the blue print for our whole body we haven’t worked out how to activate certain strings of information to generate specific proteins or body parts. \n\n",
"Simple answer: DNA knows how to *build* a body and does not know how to *repair* a body. Building consists of complicated steps involved in making organs/limbs etc. Most likely, if you need to repair an arm, you need to grow it and attach it. But it will not have the same biometric Identifications like fingerprints or vein locations (_URL_0_).",
"at each time during development the body is at an unique configuration it won't ever see again. the DNA instruction produces the configuration and depends on it to progress. there are no instructions to recreate these configurations once the development is completed. ",
"The body knows how to build a body because when the zygote is formed it is known to be a totipotency cell (has the potential of becoming different things (liver cells, muscle cells, forming the baby)) \nThis is what are known as stem cells, they are various kinds of them (totipotent, pluripotent, multipotent, oligopotent, multipotent) \nThey have the potential of differentiate into other cells to build what is needed in the place is needed. There is a lot of research to investigating stem cells and how to undifferentiate already defined cells and to bring them to a state of stem cell and redirecting them to a damaged area of the body. \nThe famous dolly sheep (cloning experiment) actually was not only to prove you can clone something (technically is not even a clone) but it showed that one single cell has all the genetic material necessary to form a complete organisms when conditions given. \nThis genetic material is turned on/off depending on to where the cell has differentiate. \nIf you have a cut in your finger, your body does fix it, but it doesnt form a liver or a kidney it rebuilds skin cells, due to the environment around it. \nIt really is a very long topic, with a lot of information and can discuss a lot of it but basically because it might take a whole deal of energy to do so and the body doesn’t have the resources to do so. ",
"The simple answer is, we can, but a wound would have to be left open for months to let this happen, and thus we would die of infection.\n\nLong ago, our wounds evolved to close quickly to avoid blood loss and infection.\n\nIf you are being eaten by a tiger, it's better to close a wound and run away than sit with the tiger for three months and wait for your fingers to regrow.\n\nDoctors are currently working with a substance (our bodies produce naturally) called extracellular matrix which acts as a scaffold for exactly this type of regeneration. Currently, the technology is used to help racehorses and prize animals regenerate severely damaged ligaments. Fingertips in humans have been regenerated, but the technology is just newly discovered. I will post more...",
"DNA contains all the instructions, and every cell has the full set of these instructions. However, only small sections of this large instruction book are \"expressed\" in each cell type - and turned into proteins and cellular machinery - the rest of it is inactive. This is part of the reason why certain cell types cannot just turn into other cell types. \n\nNow, this isn't the only reason why we can't regenerate body parts - much of that we are still trying to figure out. Some animals can, and by studying them we hope to learn more about how that happens. \n\nSource: Scientist",
"Edit: my answer is more advanced than ELI5, but is necessary due to the complexity of the topic!\n\nI think I can chime in here. \n\nThe short answer: We don't know.\nThe long answer (ELI10): Ongoing research has studied the effects of the immune system on the ability to regenerate limbs. Interestingly enough, there is an inverse relationship between degree of complexity of the immune system and the ability to regenerate. Lizards, for example, have primitive immune systems and are able to regrow tails. Ours are quite advanced which results in the formation of scar tissue instead.\n\nTo answer in a more academic way, the immune system constitutes something called macrophages, which help with many many aspects of immunity. As they relate to this topic, M1 (macrophage type 1) are initially present in wounds and help cause the typical inflammation and pain associated with an injury. As the healing continues, there is a shift called 'macrophage polarization' that causes M2 (macrophage type 2) to be present. These release anti-inflammatory cytokines like IL-10 and help promote wound healing and repair. \n\nUltimately, research has been shown that the macrophage polarization step has been hugely important in understanding the ability to regenerate. Neonatal mice are able to regenerate heart tissue, whereas adult mice produce scar tissue. There is a period of time where growing mice undergo significant changes in their immune system and researchers believe this transition is what causes the loss of regeneration. Current research is trying to figure out if we, humans, can regenerate if we can figure out a way to take advantage of the benefits of M1 and M2 phases without suffering from the loss of regenerative abilities.\n\nGraduate student in the biological sciences."
]
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[],
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"https://newatlas.com/human-body-regeneration-worm-genes/46670/",
"http://www.dailymail.co.uk/sciencetech/article-3729455/Could-humans-regrow-limbs-Genetic-switches-regenerating-tissue-traced-420-million-years.html"
],
[],
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6ns7j7 | how do ancestry reports work? | 23andme says I'm 100% European. How is that if all human life can be traced back to Africa? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/6ns7j7/eli5_how_do_ancestry_reports_work/ | {
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"Scientists have collected DNA from different ethnic groups all over the world. There are certain markers on DNA or RNA, they can calculate what mutations have occurred and how fast they happen. \n\nMitochondria (the powerhouse of the cell) are only inherited from your mother and have their own separate DNA, so you can compare all groups until you find a common ancestor (Mitochondrial Eve). There's a similar test for men, Y-chomosomal Adam.\n\nAfricans have the most genetic diversity, since those groups that left would have had a bottleneck and less variation."
]
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|
5jvge0 | how did kings know how much was in their coffers and avoid having it picked at by treasurers? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5jvge0/eli5_how_did_kings_know_how_much_was_in_their/ | {
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"This is still a problem in the present day. The answer is: you have another, independent person (an auditor) come in and make a separate count. And you warn the treasurer that this is going to happen, again and again, so they'd better not cheat because they'll get caught.\n\nFor a while the Chinese Emperor forgot to do this, and when he finally announced that auditor were coming, his staff burned down the treasure storehouse because, presumably, they knew their thefts would be found out.",
"This is actually one of the reasons writing was invented. You go back to some of the earliest records written in the most archaic systems from the most primitive cultures, and what do you find? A bunch of inventories, ledgers, lists of assets!"
]
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||
6zulb9 | how did the united states first distribute and get people to use the dollar? | Something that really confuses me is the beginning of US currency. I understand that it was at some point distributed but how? Who did they decide to give the first dollars to? And more importantly, how did they get people to start using this currency rather than to continue trading goods for services or using coins?
I guess my main confusion/need for clarification is the transition from no dollar - > to where we are today. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/6zulb9/eli5how_did_the_united_states_first_distribute/ | {
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"Early dollars were silver coins. Minting coins was just creating a standardized amount of silver to simplify using it as a commodity.\n\nMore generally, governments promote the use of their currency by requiring that tax and court-ordered debts be paid in it. If you have to pay your taxes in dollars and you don't have enough, you find a way to buy dollars in exchange for whatever it is that you currently have and the government will be ready to sell those to you should it come to that.",
"States were issuing their own currencies and some were still using British money until the Articles of Confederation, establishing an official currency, went into effect in March 1781. The US government asked for help establishing a financial system but noone came through. Richard Price (Wales) was too busy with his sheep, and Americans representing the new country in Europe were asked to scout for finance people to help; nothing came of their efforts.\n\nRobert Morris, Jr. was one of the signers of the Declaration of Independence, and one of the financiers of the Army of the Revolution. Morris was also the first (and only) Superintendent of Finance of the United States - precursor to the Sec'y of the Treasury. Insisting that the Federal Government give him broad powers to act on his own, he used his own money and borrowed from friends (and finally France) to make his own \"bank\". That was the beginning of the US Government's bank. We call them \"cents\" because Morris instituted the use of the decimal system for the Dollar. The Department of the Treasury is spawn of that original undertaking, after Morris refused a position (he wanted to be the first Senator from Pennsylvania) and told Washington to make Alexander Hamilton the Secretary of the new Department.",
"I don't know about the early times but when Nixon took the us off the gold standard they began the era of the petrondollar, Kissinger I think made a deal with the Saudis that they would only take the US dollar to buy oil. That made the US dollar the reserve currency of the world and the reason their sanctions against other countries so effective. In the last few weeks though the Chinese have announced they are going to introduce the gold based yuan that they want to use to purchase oil, which may threaten the US dollar as the reserve currency. I think this could be a huge deal and may cause gold prices to skyrocket, or more likely the US dollar to plunge. It's actually pretty interesting, I've been reading a lot about it lately on some alt websites like zero hedge, silver doctors, wolf street , SARS rocks, daily reckoning. Trying to figure it out for myself to make sure I am in a position to profit from it."
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35sbsg | when and why did universities start inflating their tuition rates so much? | Just want to understand why I'm so poor | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/35sbsg/eli5_when_and_why_did_universities_start/ | {
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"In the U.S. a large part of the rising tuition over the past few decades is universities trying to offer a better \"campus life\" than others. Instead of just offering better academics, schools started competing over who had the best dorms, dining halls, on-campus events like concerts, comedians, etc. This became an important factor in students choosing which school to attend, so schools had to keep up, but all of that is expensive. Tuition was raised to pay for it.",
"because maximum profit can't be made if you don't raise prices when customers are able to get a free loan and pay"
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1jzqja | the differences between 501c4, 501c3 and llc, and 527. | So my little group of folks are considering filing for nonprofit.
Here are the options:
1. Have the national organization file as a 501c4.
2. Have the national organization file as a 501c3 and LLC.
3. Have the national organization file as a 527.
(And then some combinations between local and national filing together)
Can someone explain to me the differences between them? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1jzqja/eli5_the_differences_between_501c4_501c3_and_llc/ | {
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"The ones that start with numbers are tax-exempt organizations under the IRS tax code.\n\n501c4 is for social welfare organizations and employee assosiations.\n\n501c3 is pretty broad and includes religious institutions, charities, educational institutions, amateur sports institutions, animal cruelty prevention, etc. etc. etc.\n\n527 is for groups that campaign for political candidates.\n\nAn LLC is a limited liability company and is a way to organize a business so that the owners are not personally liable for the liabilities of the business, but it is taxed like a sole proprietorship. It is not an inherently tax exempt status.\n\nWhat kind of tax exempt status you file for, and how your organize your group legally, completely depends on what the purpose of your group is. Section 501c lists something like 29 different categories of tax exempt organizations."
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29w78d | is there a way to get over phobias? | I hate bugs so much. They make my heart skip some times. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/29w78d/eli5_is_there_a_way_to_get_over_phobias/ | {
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"Yes. Usually Exposure therapy. Your body has an irrational fear response. Exposure therapy teaches you how to calm down during that fear response.",
"Progressive exposure. Get a kid to catch a pillbug in a jar and sit across the room from it. When you're used to it, move up to a bigger bug. Sit closer after a while. Sit outside next to a jar with a grasshopper in it, then open the jar, and watch it escape. ",
"Different things work for different people. Some people get help from hypnosis, some have a really gradual desensitization/exposure therapy. [This is a link](_URL_0_) to a self desensitization therapy. My advice would be to skip past the nonsense pre-reading to \"step 1.\" Essentially the most common way to get over a phobia is to practice relaxation techniques enough that you get really good at them. Then, you spend a few minutes every day on a \"hierarchy of exposure\" where you use those relaxation techniques. For you, as an example, the hierarchy might be for the first few weeks, to think about a bug far away from you, then a few weeks after that might be to think about a bug outside your house, then inside your house, then inside the room, then actually seeing a bug, then actually touching the bug. After each thing (like thinking about the bug far away), you'd practice relaxing yourself every day until it became second nature to be relaxed in that situation... then you'd move on to the next thing.",
"Realize that your reaction is a feedback loop.\n\nYou see/hear/experience/sense something. You think about it anxiously. Your body has an anxiety (fight or flight) reaction. You think about it more anxiously. Your body has a stronger anxiety reaction. Your body feeds your mental anxiety, and that mental anxiety feeds your body's fight or flight response. And so on, and so on, as it snowballs...\n\nThe key is to short circuit the snowballing feedback loop. \n\nThe easiest way to do this is to continually expose yourself to the anxiety provoking thing/situation, until you get used to it, and you're able to to be exposed to it without having that \"anxiety < -- > fight or flight\" reaction. ",
"As others have said, exposure can be a way. It certainly worked with my extreme fear of E.T. (Yes, the cute alien)\n\nEDIT: I still get a small adrenaline rush whenever I see E.T. for the first time in a while, so I guess I'm not completely over it."
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3mkn43 | why do we grab our chest when we are startled? | "Oh my God you scared me" | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/3mkn43/eli5_why_do_we_grab_our_chest_when_we_are_startled/ | {
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"My guess would be it has something to do with a natural reaction to protect the heart area of your chest. Sort of like an instictive fear response. ",
"I just did a quick google a managed to find a little info that may help\n\nThe responses of people to a startling incident vary widely between the fight, fly, or freeze options. When startled, people may wildly flail their arms, or suddenly raise their limbs in protective poses, or duck to avoid an object. The shocked and surprised often back pedal, jump back, or run away from a frontal stimulus. They may clutch a rail, or furniture to prevent from falling. Their knees may buckle, causing them to fall down. They may drop the things they are holding.\n\nThey may freeze, or instantly follow orders. They may clutch their chests, faint or even suffer a temporary heart attack The aggressive ones may curse or throw things at the object, which startled them, or strike out at them.\n\nSo it sounds like it clutching your just is a response you hafe in order to protect your torso."
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80f2dq | what is a sanctuary city in the usa and what is typical daily life like for illegal immigrants who live there? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/80f2dq/eli5_what_is_a_sanctuary_city_in_the_usa_and_what/ | {
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"A sanctuary cities is one whose local government refuses to help the Federal government in checking to make sure an immigrant is here legally, or retaining someone who is here illegally till the Federal government can take them into custody. The Federal government can still send agents after you, they just do not get help from the local government which makes it easier for you to avoid capture and easier for you to keep from being found to begin with. ",
"Trying to keep this as neutral as possible for a highly politically charged topic.\n\nSan Francisco's description is pretty clear, and might be worth looking through.\n_URL_1_\n\n\"Sanctuary city\" isn't a specific legal term, and different places that call themselves sanctuary cities go about it different ways. In the broadest sense, it means that the city is not going to spend any money or resources enforcing federal immigration law. For example, often local police in sanctuary cities are banned by city or local laws from asking people about their immigration status. So if you're in the country without a legal immigrant status and you're pulled over by a cop, they can't ask you if you're \"legal\" and then detain you and hand you over to ICE to be potentially deported. [This does happen in non-sanctuary areas.](_URL_0_)\n\nPeople without legal immigration status can also sign their kids up for school and access other city services without having to answer questions about immigration status.\n\nDaily life for you as someone who was overstaying their student visa would be hard to say much about except for that you would probably be less worried in your daily life that a small slipup (like getting pulled over while driving) could lead to your deportation.\n\nPeople who are for this policy say that it's the city's duty to support their residents, and that threatening to report people to immigration authorities makes them less likely to put their kids in school, be able to support themselves and their families, etc, and to keep people from getting basic services and keep them in constant fear of deportation based on their immigration status is immoral.\n\nPeople who are against it say that these people broke the law to come here, and by refusing to cooperate with federal immigration authorities city officials encouraging more people to come here illegally and depriving citizens and legal immigrants of resources that could be helping them. They also say it's illegal for a city to try and supercede federal law, and that it allows people who are criminals and should be deported to escape detection.\n\nI'm not trying to advocate for either side (I have my opinions, but I'm not going to say them here). ",
"immigration offenses are the purview or the federal government, specifically ICE. so technically any state or local authorities don’t *have* to get involved when someone is in the country illegally.\n\na sanctuary city is a city that has some sort of policy or statute to specifically *NOT* collaborate with immigration authorities. \n\nthe most common example you’ll hear is if someone gets arrested or detained for an unrelated offense and is in the country illegally, the city won’t hold on to them for immigration officials to collect later. \n\nso, if you were a UK citizen who overstayed their visa and was here illegally, and you got pulled over for speeding, the cops wouldn’t then put you in jail after giving you a ticket for being here illegally. a city without a sanctuary city policy may or may not do so.\n\nso, essentially, an illegal immigrant is more easily able to participate in public life. they can operate vehicles without nearly as much risk. and interactions with law enforcement don’t carry the risk of deportation, so they can rely on and cooperate with officials more.\n\nthat’s not very ELI5, i guess, but yeah. "
]
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66eash | how do lotteries that reward $1000 a day work? | I've seen commercials for lotteries where if you win, you get $1000 a day for life. How does this work, how can they keep supporting all the winners? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/66eash/eli5how_do_lotteries_that_reward_1000_a_day_work/ | {
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"That really is not that much money in lottery terms. That is $365,000 a year. Over 10 years that is only $3.65 Million, and $14.6 Million over 40 years.\n\n$14.6 million is not that much money in lottery terms. ",
"Basically they just calculate the money required to pay that for life and throw that into an investment account for each winner. $1k/day estimated for 45 years (probably a reasonable life expectancy for the winner) gets you $6.5mil required to actually pay out for 45 years, assuming it's invested at 5%. If a ticket is $1, and half goes to the state, a quarter to small prized, and a quarter to the jackpot, then they need to sell ~26 million tickets per jackpot, so odds of 1:26 million would make the numbers work easily.\n\nFor record, the odds of the cash4life jackpot is 1:21million, indicating they use about 30% of the ticket price for the jackpot."
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2m06wa | why does gillette advertise against their own product? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2m06wa/eli5_why_does_gillette_advertise_against_their/ | {
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"Gillette is by far the leader in the razor market. The Fusion blades are more expensive than the Mach 3 blades, so they get the most bang for their buck by convincing Mach 3 users to upgrade rather than getting others to switch from competitors."
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||
68o54e | why isnt the number 11 pronounced onety-one? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/68o54e/eli5why_isnt_the_number_11_pronounced_onetyone/ | {
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"English is a Germanic-derived language, and Germanic cultures counted by twelves sometimes instead of tens. This is why the concept of a \"dozen\" exists.\n\nThe words *eleven* and *twelve* come from *einliff* and *twaliff*, Germanic words meaning \"one left\" and \"two left\", i.e. you have one/two left after taking ten away.",
"Or one-teen, to be consistent with the others until 19. \n\nAnyway, we count in base 10. But it's not the only one. Base 12 is also present (12, 24, 60) and used. Many languages have specific words until 12 and then start the \"regular\" ones."
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3ppbn4 | why are kids taught to use "x" to mean multiplication until the age of ~11, when they switch to "·"? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/3ppbn4/eli5_why_are_kids_taught_to_use_x_to_mean/ | {
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"It is very important that they learn what a punctuation mark or decimal point is. It may be difficult for young kids to discern the difference between . and · especially when handwritten.\n\nx as a multiplication symbol only works until you need to learn algebra. Then x becomes a variable. It is then necessary to use a different distinct multiplication symbol."
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2lrhgk | where do we find the room to bury the dead? | Maybe I'm missing something here, but it seems that the amount of people who die after each consecutive generation far outweighs the land set aside to bury the bodies (graveyards, burial grounds etc). | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2lrhgk/eli5_where_do_we_find_the_room_to_bury_the_dead/ | {
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"Individual graveyard burial generally doesn't last forever. Eventually the soft parts of a body will decompose and the remains are dug up and stored more efficiently in something like an [ossuary](_URL_0_). \n\nAlso not everyone practices burial in this way. Cremation (burning the body and collecting the ashes) remains popular in many countries and is very efficient with its land use. Some people prefer to have their ashes scattered, and even if they're stored in an urn it's usually small enough that the family can take it home, or they can be efficiently stored elsewhere. \nThen there's more unusual practices like sky burial where all of the body is deliberately fed to birds and other scavengers. Like cremation and scattering, this doesn't require any land for remains or a permanent marker.",
"Remember, there's also cremation. And there's the buildings were bodies are places in a wall above and below other people.\n\nThis is probably going to become a real big issue within the 50 years. Where do we bury billions of people? There's a lot of unoccupied places in the world to build cemeteries, but they might become more remote in location as the premium cemeteries will be closer to the living population.\n\nOr cemetery cities might pop up like Colma, CA",
"In France it's common to \"rent\" a plot. I don't know the length of the leases, but the put you in the ground for a while, the people you knew can come and weep, then eventually they dig you back up like Lobsang said, they do something else with your bones. It's been a long time since I studied French culture, so I can't remember the exacts, but ossuary may be the ticket. I think big cultural personalities are pretty much left alone. I went to Pere Lachaise in Paris and there were some pretty cool figures from history there. ",
"It's already an issue. I know a family that's moving a beloved grandfather's grave from their ancestral home overseas to here in the US, mostly so he will be buried next to his wife and so that they can visit his grave regularly. They are selling his plot in a densely packed overseas city for the equivalent of about $200k, so grandpa's investment in a plot in the 50's is going to put a tidy sum in the college funds of his 10 or so great grand kids. \n\nThe demand for good grave sites in their home city has climbed to the point where an individual plot in an older, centrally located cemetery can fetch that much or more. Here in the states where we have less geographical pressure I'm sure we will do what we always do, which is fuck around and continue to waste our resources until the last minute, then do down thing drastic. ",
"Every once in a while, you hear a news story about outrage over a cemetery digging up graves to reuse the land, or burying bodies on top of each other, etc. An individual cemetery has a limited amount of land, but they want to stay in business, so there you go. Most people are forgotten within a few decades of their death, and the people who run burial grounds take advantage of this.",
"To add to what others have said: have you ever walked past a graveyard, and noticed that the ground level of the graveyard is far higher than the land around it? This is because the ground gets reused, and it isn't uncommon for fresh graves to be dug above older graves, raising the height of the graveyard respective to the rest of the land. This is discussed in Bill Bryson's book *At Home*, and he points out that in a small English village with a tiny population, the graveyard will have had tens of thousands of burials in its time. Basically, your final resting place isn't that final - eventually someone else is going to use it!\n\nTL;DR: Graveyards are deeeeeeeeeep.",
"In Sweden, everybody has a right to graveyard spot free of charge for 25 years. After that, when you're relatives stop paying, the grave is reused. ",
"There is a graveyard in Edinburgh near the castle that is about 25 feet above street level. The original graveyard was at street level, but when they ran out of room, a new layer of dirt was added and more layers over time (several hundred years, according to our guide). We were warned to stay on the path because tips of headstones from the previous layer were sticking up through the grass, and therefore a tripping hazard.\n\nAt least, that's ONE way to deal with it....:P\n\nEDIT: that graveyard is not new, obviously. I doubt they are still using it for new burials. But prior to the renting idea, this probably happened a lot."
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d8u3jr | how much water is on the international space station? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/d8u3jr/eli5_how_much_water_is_on_the_international_space/ | {
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"Yep, recycling is critical, since there's really no feasible way to constantly be sending new water tanks into space to refill drinking water supplies. \n\n\nFrom what I've read, the ISS is able to keep a reserve of 530 gallons of drinking water in case of emergencies. Since the ISS is made up of various modules that were sent into space at different times, I'm not entirely sure which module was launched with the reserve water. \n\n\nThe ISS is actually split into two sections: The American side, and the Russian side, and each side has a different recycling system. The American part has equipment that collects condensation in the air, shower water, and urine, and turns it back into drinkable water, and that equipment produces somewhere around 3.6 gallons of drinkable water per day. On the Russian side they produce about the same amount of water, or a little less, but they only collect condensation and shower water. In fact the U.S. astronauts sometimes borrow the Russians' pee when they want to make a bit more drinking water."
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4xqmkp | different types of radiation | Why do different particles emit different types of radiation (alpha, beta, gamma, etc)? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4xqmkp/eli5_different_types_of_radiation/ | {
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"Think of radiation as a wave. The energy of a particle determines what wave it is. Kind of like light from stars. The higher the energy the whiter it is. On the lower energy scale you get red. Now as an atom starts to decay certain particles are released due to the weakness of the atoms containment energy. Depending on which type or types of particle escape you get different forms of levels or waves radiation.",
"Others here have explained what the three types of radiation are, but you asked *why* different particles emit different types of radiation. By \"different particles\", I'm going to assume you mean \"different atomic nuclei\", because that's where radiation typically comes from.\n\nThe nucleus of an atom is made of protons and neutrons, held together and stabilized by the \"strong\" nuclear force. Nuclei are most stable when there are about equal numbers of protons and neutrons -- tending toward a slight excess of neutrons for very big nuclei.\n\nThe various isotopes can be plotted on a protons-vs-neutrons graph like this: _URL_1_#/media/File:Half_Life_Valley_of_Stability.jpg\n\nThe colors indicate whether a particular isotope is stable or radioactive. The black line near the center is the [\"valley of stability\"](_URL_1_): nuclei will radioactively decay in ways that move them closer to the valley of stability. In terms of their nuclear energy, it's like they're \"rolling downhill\" into the valley.\n\nIf a nucleus has too many neutrons, the \"weak\" nuclear force will cause one of them to transform into a proton. Since a proton has a positive charge, a negatively charged electron is also created so the total charge is unchanged. This electron flies away as a beta particle. The nucleus now has one less neutron and one more proton than before, moving it closer to the valley of stability.\n\nOn the other hand, if a nucleus has too many protons, it will do the opposite. There are two different processes, but either way, a proton is transformed into a neutron, bringing the nucleus closer to the valley of stability.\n\nFinally, very big nuclei can get rid of two protons and two neutrons together -- this is an alpha particle. This moves the nucleus diagonally down and to the left on the stability diagram. This might not seem like it helps, but since the valley of stability is curved, going down and to the left does make the nucleus more stable.\n\n[This figure](_URL_0_) shows the different patterns of decay for each isotope. You can see that the nuclei almost always decay in ways that make them more stable.\n\n... but one last thing, I haven't explained gamma rays yet. Whenever a particle shoots away from the nucleus, it starts to quiver like a blob of jello. This extra kinetic energy is lost through the emission of an electromagnetic wave -- that is, a gamma ray. Almost every radioactive decay also emits a gamma ray, to get rid of the excess nuclear \"vibration\".\n\nSo to sum up: if an atomic nucleus has the wrong ratio of neutrons to protons, it will radioactively decay in a way that changes that ratio and makes the nucleus more stable. Alpha, beta, and gamma decay solve the problem of too many protons, too many neutrons, or too much kinetic energy, respectively."
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5jng4d | how humans didn't get eaten by predators who heard babies screaming when humans lived in the wild. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5jng4d/eli5how_humans_didnt_get_eaten_by_predators_who/ | {
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"Humans built fortifications, often in caves. Lived in fairly sized family bands that offered constant protection of the group. And had weapons with which to defend themselves. So we did not have pressure to evolve \"silently hide\" instincts while infants. ",
"Predators (at least modern ones anyway) look for easy meals. It's not worth risking injury.\n\nIf you find a human child *by itself*? Snacktime.\n\nIf you hear a crying child, go to the noise, and find several adult humans with pointy sticks and fire? Not worth the risk. ",
"If a predator is close enough to hear a crying child, it's close enough to smell a group of people. So there is no great survival advantage to being quiet. A bear can smell a human from 2-3 km away.",
"Humans, and their cousin species stay in groups. They have been armed with fire and stone weapons for houdress of thousands of years, and have been capable of barricading themselves to some degree for hundreds of thousands of years. In short, a species that made it a habit of attacking humans would be in danger of going extinct.",
"Predators are usually highly risk averse. Why take the chance of a risky meal when you can wait for an easy kill.",
"If you were hungry in the woods and stumbled upon a crying baby bear surrounded by adult bears with crazy bear-tech weapons living in scary bear-tech structures lit up with bear-magic would you try to make steak?",
"Babies didn't cry as much when humans lived more \"in the wild.\" Crying is generally a sign that the baby is hungry or needs to be held.\n\nDo you ever watch primates with their babies? The babies practically live on their backs and stomachs for the first year(s) of life, being constantly held and nursed. Early humans likely held babies the same way.\n\nIf you know parents of young kids, see how much they cry and when they do. Mom's who co-sleep allow the babies to wake up and feed at will, so they don't do much crying during the night. Babies in a crib will scream constantly until they are held.",
"Also, don't forget rocks. Humans and our various primate relatives, throw rocks and stuff. Even women and children can contribute on that front, and have continued to do so when nothing else was around to protect themselves to this very day. This tends to be very painful and discouraging to many predators. They show up, there are lots of people, including big people with spears, and most or all of them are probably throwing stuff and yelling.\n\nA lot of the time, they just leave. It's not worth it and it hurts.\n\n"
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52a1yj | when would a doctor use stitches, and when would he use staples? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/52a1yj/eli5_when_would_a_doctor_use_stitches_and_when/ | {
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"They are interchangeable. Sort of.\n\nA stapled wound and one closed with a non-absorbable suture are similar. Both require medical aid to remove, and for this reason day surgery and short stay surgery usually use absorbable sutures. These dissapear over a few weeks as the body breaks them down.\n\nCertain procedures are normally stapled though. For example if there is a risk of bleeding, especially if it will quickly affect the patient, eg carotid surgery where a haematoma might obstruct an airway.\n\nThere's also surgeons preference, and speed issues, so.... Either in many situations!\n\nEDIT: There is potentially a greater risk of [infection with staples](_URL_0_) however.\n\nSource- 20 years OR experience ",
"Part of her consideration is also wound healing and cosmetic appearance. Well placed stitches have a better cosmetic result as compared to staples or glue. No one wants their face stapled, but staples on the scalp are common where hair growth will hide scar tissue. ",
"Not a doctor but I've had both because of a dangerous hobby (RC helicopters) \n\nStaples tend to be weaker and more temporary than stitches. I keep a surgical staple gun in my kit when I fly so if I had to I could patch myself up enough to make it to a hospital. The staples can and do pop off because they only pinch themselves on much like the hook like pinch between a thumb and index finger. If the wound is stretched or disturbed one could pop off opening it up. \n\nStitches are harder to do especially to yourself, but they are more robust and can handle more physical activity without breaking. \n\nIn some cases a doctor may also use surgical glue for certain wounds. I had a multi rotor fly into my chest and the 4 blades opened me up like a knife and 2 of them had to be glued closed. \n\nOnly the very tip of the staple stabs into your skin. It doesn't close on the back end the way a staple in a piece of paper does. This makes them very easy to remove with a surgical staple remover which simply bends them in the very middle, causing them to form a M shape and the legs retract and slide out. They are very easy to install though without any training so in an emergency they can temporarily close a wound while you seek treatment. "
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30bnpn | how is it that populations of people all across the planet in different countries all developed at relatively the same rate, when there was no means of communication between them? | Why didn't some countries develop thousands of years before others before cross-continental travel? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/30bnpn/eli5_how_is_it_that_populations_of_people_all/ | {
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"Some did. Compare the Europeans of Columbus' time to the Native Americans. They were much further advanced by hundreds of years.",
"They didn't develop at the same rate, it's just that the weaker ones were destroyed/absorbed by more powerful and technologically advanced ones. There's just little record of them left.\n\nWe know about Native Americans being decimated by the colonists from Europe with far superior tools and tech. There are still tiny tribes in the world today that are pretty much in the stone age compared to other societies.",
"A lot of the world communicated across the silk roads others had similar problems and made similar solutions everything was a matter of taste. ",
"We definitely aren't all developing at the same rate, these guys can't even make fire yet _URL_0_"
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5oqclk | can defense attorneys 'throw' a case if they know their clients are guilty? | [deleted] | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5oqclk/eli5_can_defense_attorneys_throw_a_case_if_they/ | {
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"That would be unethical. In our society, even the guilty are given competent representation. What they can do is seriously suggest that the person take a plea deal. Part of the process requires a good defense or the conviction can be overturned on appeal.",
"Yes, they could 'throw' a case.\n\nHowever, that's a serious ethics violation which would almost certainly cause disbarment if found out, and not only that, the conviction could then be appealed based on ineffective assistance of counsel (embodied in the 6th amendment).\n\nIf it makes it easier to wrap your head around, think of defense lawyers defending the integrity of the judicial system, not just their client. The idea being, the system must obey all of its own rules in proving that someone is guilty, or else it's a dishonest system and could easily \"prove\" that an innocent person is guilty next time. Defense lawyers are there to help ensure the system stays honest."
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9193ct | why isn't time read literally as numbers but instead the letter o is said to represent zero? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/9193ct/eli5_why_isnt_time_read_literally_as_numbers_but/ | {
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"In English (at least American English) unless you have a bunch of zeros in a row you almost always say \"O\" for every single number, not just time. ",
"\"Oh\" is one syllable and \"Zero\" is two. People are lazy.\n\nWe changed the word \"Colour\" to \"Color\" or \"Honour\" to \"Honor\" because the U is silent and people were too lazy to write it."
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2i3xw7 | standard error in measurement. i have no idea. what is it's relation to standard deviation? (rhyme not intended) | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2i3xw7/eli5_standard_error_in_measurement_i_have_no_idea/ | {
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"Standard Deviation refers to variability in general. If you're learning this in a class, it probably is implicitly meant as the standard deviation of the sample in most cases.\n\nStandard Error is the standard deviation of whatever measure you're trying to estimate. Since in statistics you're typically looking for the mean, Standard Error given no other context generally refers to the Standard Error of the sample mean. In other words, it's the standard deviation of the means of various samples (Technically, they have to be the same size samples, and indepentedly, randomly drawn from the population). \n\nFor exmaple, say we care about the average height of people in New York. You hire 300 people to take independent random samples of 100 people throughout the city. This will give you 300 samples of size 100 each. \n\nYou then take the mean of each of these 300 samples to come up with 300 sample means. The standard deviation of these 300 sample means should be roughly equal to the standard error estimate from any one sample. \n\nHope this helps"
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1jbtv2 | how do reality shows record reactions in monologues like they are happening for the first time? | How do they make reactions feel recent? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1jbtv2/eli5_how_do_reality_shows_record_reactions_in/ | {
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"The people giving the interviews are asked to reenact their initial reactions. Its all just good (or in most cases, bad) acting. ",
"They are called \"OTF\"s or \"On the Fly\" interviews. The producers record an interview with the person after the fact (ideally, as soon as possible after the moment they want to reenact). They try and remind the person what was happening and help them feel the same feelings again."
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3ovn62 | how does viagra actually work..? | Thanks | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/3ovn62/eli5_how_does_viagra_actually_work/ | {
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"Without getting really technical, Viagra is a type of drug called a Vasodilator. Vasodilators relax the muscles and arteries so more blood can flow through them. Think of a Vasodilator as a hose. If you have a hose that has a 1 Inch Diameter, only so much water can flow through it at full blast. A Vasodilator would turn that 1 Inch Diameter hose into a 2 Inch Diameter hose so now significantly more water can flow through the hose at full blast. This is often why Vasodilators are often prescribed to people who have low blood pressure. For your own information, the opposite of a Vasodilator is a Vasoconstrictor. It does the exact opposite of a Vasodilator; instead of increasing the amount of water that can flow through a hose, it restricts the amount of water that can flow through the hose by decreasing the hose's diameter. \n\nViagra, in particular, works because the it targets specific mechanisms in the Penis that are directly tied to vasodilation. Without getting too deep in the interactions, Viagra prevents an Amino Acid that happens ot be found in the muscle tissue and arterial linings in the penis from \"degrading\"... eh... Being used up. Viagra basically \"blocks\" the body's mechanisms from removing this Amino Acid while the Viagra is in your system. Eventually it gets used up, but Viagra slows the process down significantly. As there is more of this Amino Acid, more blood will rush through the arteries in your Penis and result in longer lasting erections. \n\nThat help? "
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23hrb5 | bedsores | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/23hrb5/eli5_bedsores/ | {
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"When you press down on your skin it prevents your blood from moving naturally. This lack of blood to the area causes the tissue to break down over time, if left over a prolonged period of time it can cause pretty severe damage and infection.\n\nSafe rule of thumb for prevention and healing of minor injuries, change position every 2 hrs. If its more than reddened skin (stage 1) it needs to be seen by a health care provider."
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q2171 | how do leases work? | I'm talking about leasing a car, by the way. I am aware for the most part that you have to pay a certain amount of money due at signing and then monthly payments, but are there other payments that they charge you? How does it overall work? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/q2171/eli5_how_do_leases_work/ | {
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"It's like renting, but long term. Also, usually harder to get out of.",
"Be careful if you drive a lot, there are sometimes fees for excessive mileage.\n\nAlso, most people consider Leasing, financially, the worst possible choice in terms of \"owning\" a vehicle. So I would recommend you be absolutely 100% sure that having a brand new vehicle means that much to you before going forward.",
"These are the things that should be covered in public high schools, instead of all the bullshit they do throw at you"
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c8g1ms | since the hypothalamus is located near the brain and it regulates the body's temperature, how would the human body react if the head is at one extreme temperature and the rest of the body is at an opposing extreme temperature? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/c8g1ms/eli5_since_the_hypothalamus_is_located_near_the/ | {
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"The hypothalamus doesn't sense its own temperature in order to regulate the body. It gathers the data from nerves all over the body and uses that. If most of your body is hot but your head is cold, the hypothalamus will \"know\" that and will tell the body to cool itself down. \n\nAlso, your body is usually pretty good at evening out the temperature throughout, because of the blood flowing around. So even if your head is in a much colder *environment*, that doesn't mean that the head *itself* is much colder (except a few extremities like ears and nose). What's more important is the total or average heat exchange between your body and the environment around you."
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6tkfuj | how do actors appear dead in movies and films so that their chest isn't moving from breathing and their heart beating | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/6tkfuj/eli5_how_do_actors_appear_dead_in_movies_and/ | {
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"Sometimes they don't. I love catching someone breathing during a tv show. Law and Order and Criminal Minds is a gold mind. Spotting moving corpses while watching is a running competition I have with my husband. \n\nI think the camera crew tries not to linger on them too long to reduce the amount of breathing on film..... anyone in the film industry willing to weigh in? I'm not positive. ",
"It varies depending on what shots are needed. Mostly actors hold their breath or practise shallow breathing if the shot is long. For autopsy scenes they have dummies. I think if its a problem they can have a frame over their chest so they can breath under it. Mostly they just cut away before its a problem. ",
"One thing you can try at home to illustrate how easy it is... \n\njust lay down on your couch for 5 minutes and rest if you aren't physically active you can slow your breathing down by quite a bit, and even hold your breath for quite a bit longer than normal. \n\nKeeping in mind that many of the entire scenes you see with a \"dead person\" laying there is actually a composition of many separate shots. If you only have to hold your breath for 30 to 45 seconds for the director to get the shot, it's not a huge deal for most actors/actresses. ",
"The simplest method is for the actor to hold their breath during the take. The heartbeat isn't a problem, because that's not noticeable.\n\nA scene involving a dead body may last quite a long time, but like most scenes will typically be composed of a number of different shots, each shot lasting just a few seconds -- so an actor only needs to hold their breath for a very short while each time.\n\nSometimes they do breathe, and if you're sharp-eyed, you'll notice it. Of course, an actor playing a corpse can ruin a shot by coughing, sneezing or even laughing, but that's not a problem either: reset everything, and reshoot the scene.\n\nOn stage, it's more of a problem, obviously. In fact, \"dead\" actors involuntarily laughing is such a big problem, that in British theatre it is known as \"corpsing\". This has become generalized to any situation where an actor laughs inappropriately; any time you see a reference to an actor \"corpsing\", it means they ruined the shot by laughing.\n\nOf course, these days it's possible to use CGI to make an actor's chest stop moving, if the movie's budget will allow. Another technique is to use a dummy in shots where viewers won't be able to see the difference: in the movie *Swiss Army Man*, for example, Daniel Radcliffe plays a corpse washed up on a beach. For some shots, they used [a creepily lifelike -- if that's the right word to use for a dead body -- dummy](_URL_0_).",
"Yeah usually it's a matter of just trying to edit your shots around any breaths the actor takes- dummy models and frames over bodies etc will only be used as a last resort if the shot really needs to hold for a long period of time, in short film and tv these are the first kids of things to get scrapped for budgetary reasons. Complicated models will likewise only be used if budget is allocated to specifically require them for narrative reasons (autopsy or the like). \n\nHowever sometimes breathing might not be noticeable during the take and necessitates removal in Post Production. Usually it's a matter of taking a still frame of the actors chest, applying matching animated video/film noise or grain back over the image so it matches the surrounding frame and doesn't look too still and 'stuck on', and tracking it back into the image to match any camera movement, 'painting out' the original breathing chest. This is easy with static shots; the more camera movement or shifts in depth of field, the harder it is to do with just a 2D still. \n\nI was editing my short, and trying to cut around actors breathing and blinking became a nightmare, so I had to add it to the infinitely growing list of After Effects jobs and fix it digitally. Got lucky with one shot, just an overhead still angle. The other was painful, the shot was dollying backwards to reveal the body, so 3D space, shifting focus and foreground movement. Ugh. Nightmare "
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6wbc3k | how does the technology that sees if tennis balls are in or out work, and how come it hasn't completely replaced linesmen? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/6wbc3k/eli5_how_does_the_technology_that_sees_if_tennis/ | {
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"It uses camera images. The exact location and specifications of the camera, tennis balls, field lines are known. Then by analyzing the size and location of the ball on the different camera images, they can determine its actual location. \n\nWhy hasn't it replaced linesmen? First of all it's extremely expensive to set up, so in the near future it's never going to be a universal system. Secondly I'm not sure if it's possible to have it activated in real-time, to call immediately when a ball is out. Given that in football goalline technology seems to work that way, it looks possible, but I don't know the details. Finally tradition is very important in tennis, which could hold back some possible advancements. ",
"I know more about this than a lay-person should, but that's perhaps because I'm considering starting a business in this area. On this, you can AAMA - I know quite a bit.\n\nI also know this is _way_ more info than you actually care about, and nobody is going to care about this, but I enjoy talking about it, so, here goes:\n\nThe system you're talking about in tennis is called [Hawk-Eye](_URL_1_) and the first time I saw it in use was during a cricket match being shown in the UK where the broadcaster had brought it in to understand very subtle decisions almost impossible to judge by eye (cricket has a rule called \"LBW\" which in particular, is hard to get right sometimes by sight), and it quickly got engrained into the top tier of the game.\n\nThere are other systems as well. Ever wondered how \"they know\" your favourite soccer player has run 18.2km this game? That's almost certainly from the [ChryonHego](_URL_2_) Tracab system.\n\nWhen it comes to pass completion, shots on goal, etc. that data is probably coming from another system called Opta. That relies on a mixture of camera tracking and human event classification (they have people at games saying \"that frame was a pass, that frame was an attempt at goal, etc.\"\n\nIn Rugby the players are often wearing positional tracking devices that also track heart rate and letting coaches know how players are performing in real-time. I believe NFL does this too. Basketball has a mixture of systems, and in cricket, they have even more toys (I'll come back to that). \n\nYou are probably also aware that in motorsports, the objective has become \"a driver moving as large a collection of sensors as possible around a track as quickly as possible\", because the more sensors you have, the better you are at managing the data, the more likely you are to win. Hilariously, just this weekend, one F1 team has shown that their [positional analysis is easy to fool and can lead to stupid decisions](_URL_0_).\n\nThe positional tracking systems all have similar concepts: film something, then analyse each frame. In the case of Tracab and Opta, they're happy with 25 frames per second, the same as most broadcast TV systems. I would argue it's a little too low for accuracy.\n\nHawk-Eye is a much higher frame rate (500-1000 frames per second) that should aid with the accuracy. Each frame is broken down in terms of object recognition: here are the lines, here's the ball. Now look at the relationship between them and produce a data frame. The data frame will have x, y, z co-ordinates of a ball in relation to a line or some other aspect you care about, and can be fed into a piece of software that can call \"foul\" or \"goal\" or whatever you need.\n\nNow, why has it not all replaced officials? It's obviously already used to augment officials. In some tennis competitions you can actually hear Hawk-Eye make a noise on fouls that is effectively taking the place of a linesman. In EPL games, goal line technology using something like Hawk-Eye (not ChyronHego, I believe), is used to let a referee know the ball just crossed the line in case it's not obvious to them.\n\nFor some scenarios then, it is being used to replace linesmen. There are three reasons it hasn't yet succeeded in removing them completely, I think.\n\nFirstly: cost. It's not cheap. There are a lot of problems they have to take into account in getting this far. Wind, light, shadows, floodlights causing multiple shadows, they all need to be dealt with. That has led to R & D costs being quite significant.\n\nThey are proprietary systems that cost a fortune to develop, and it's a bit of a closed-shop monopoly. Setup requires a fair bit of work and there is normally a team of people running it behind the scenes at each game where this technology is deployed.\n\nThat cost is not a problem with the top tier, but the top tier of every sport normally knows its future lies in lower rungs and \"grass roots\" forms of the game. It's important that even the second division (where these systems can't be used), look and feel like the top tier. And ideally, it should be possible to play the game on a Sunday afternoon down your local park without it seeming to be futile.\n\nHuman judges aid with that. They signal \"you can do this\". The sports in which that's not possible (F1), still have alternatives, and there are some measurement systems (timing, speed, etc.) that are accessible to teens with a desire to soup up their Corolla.\n\nSecondly: not all in-game events can be tracked using these systems. Hawk-Eye can track a ball near a line being foul or not, but it can't easily tell whether a player's foot is over the line it should not be when serving, for example. \n\nEven in cricket where Hawk-Eye first made its reputation, detection of foul balls (when a bowler steps over a line) has to still be done by umpires and video review. Whether the ball hit a bat or not is done by audio detection (snick-o-meter), and heat-sensitive camera (as the ball brushes the bat, the friction warms it up enough to show as white hot on an appropriate camera). The technology isn't quite there yet to make it possible for these events to be done through camera analysis alone.\n\nThirdly: accuracy. It's pretty damned good in some scenarios but less so in others. I competed in the Manchester City hackday in July 2016 (was in the winning team, too) where we got access to Tracab and Opta raw data from some historical games. In some of those frames we were seeing the football travelling - according to their systems - at 1,500m/s - which is about Mach 5. It clearly didn't actually do that (I mean, I think Yaya Toure is _great_, but he's not _that_ good), so where did the error creep in? \n\nThat casts doubt, and to my mind, just enough to not allow it to be determining the outcomes of games on which millions of pounds and entries in history books are determined.\n\nHawk-Eye's higher frame rate is likely to make it much more accurate, so you can see it making more inroads into official calls. It makes most sense in contexts of positional review (cricket, tennis, goals in soccer), and ideally in phased-play games where there is a lot of stop-start and reviews can be done without disrupting play.\n\nTennis lends itself to all this perfectly, so the only honest answer I can give you as to why it's not everywhere is quite simply cost and the fact some in-game events can't be done through hawkeye so they need the official anyway. They'll defer to humans allow Hawk-Eye on review where it has the time to churn the data rather than in real-time.",
"A lot of sports value tradition over technology so its important to still have people on the field saying yes or no. MLB didn't even allow instant replay until 2008 which was decades after it became prominent in other sports and that delay was detrimental to the game. But lots of people opposed it because arguing with the umpire over differences in opinion is fundamental to the culture of baseball. If you scrap the humans, then there is no one to argue with and it diminishes some of the excitement of the game. Tennis is somewhat the same and the drama is a lot lower if there is a computer making the calls. ",
"To add on p7r's magnificient response, the availability is really dependant on the costs and the situation. Currently in tennis, not every big tournament has the system implemented on each and every court. The system is used as a way to contest referees and linesmen calls and not systematically call every single ball inbounds or not. The whole rallies aren't probably saved for data storage purposes, but impact points can be used on broadcast to show statistics (such as where the services landed all-match), and if the system has a 99.9% accuracy mark, there's less likely to be a lot of wrong calls upon using it 1000 times rather than 100000 times.\n\nAlso the cameras are obviously situated 360° around, to be as accurate as possible in spotting whether there is a space as small as half of a millimeter between where the ball landed and the line (which is basically the whole point, to see if the ball and line have a contact). Many cameras are essential because you wouldn't want the player's body to stand in the way of your only camera.\n\nFinally, even if the human eye isn't as accurate as the machine, a linesman wouldn't have system errors or accidentally lose a file. While it's not common, I've witnessed tennis matches where the replay wouldn't be available for numerous reasons, so the game cannot be dependant uniquely on that system for now. Also, a human response is much quicker, and the players love to keep the flow going in a high intensity game."
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batcsj | which consequences of a dam being built lead to environmental change/damage? | I understand that when a dam is built it frequently has massive effects on the surrounding nature (though I'm unsure to what degree this damage is caused up and down stream respectively).
But why? Disregarding the damage that BUILDING the dam would cause for a moment, wouldn't this be a zero sum situation? Water has to build up in the reservoir first, sure. But the input doesn't change. Eventually the dam has to be opened to allow through an amount of water equal to what the river brings in or it would flood over the top.
By neccessity then, the same amount of water would flow further down the river, yes?
So where does the harm to nature come from? Is it solely because of the building of the dam?
Thanks in advance, everyone. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/batcsj/eli5_which_consequences_of_a_dam_being_built_lead/ | {
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"One problem is that the dam floods the valley behind it, turning it into a lake. This kills virtually everything that was previously growing in the valley.",
"Opening a spillway creates a a current of water the down stream river life is not used to. From 1500 cfm to 35,000 cfm will wash the life of the river down to rock. This is only one issue.",
"One problem is that fish can’t swim *up* a dam to spawn. The Southern Resident orcas are starving to death because they can’t find enough salmon and a major cause of that is dams that prevent salmon reproduction. ",
"For a hydro dam, the water is eventually released downstream. However, this may be very far downstream. Look for photos of penstocks (_URL_0_). The turbines / generators need to be at a much lower elevation that the dam, to extract as much energy from the flowing water as possible. \n\nLook at the map on the first page of this PDF: _URL_1_\n\nFrom the dam, the water misses most of the river as it goes through the power tunnel, and then is released right at the ocean.\n\nFor irrigation / drinking water dams, the water is piped to other locations. This reduces water level / flow in the river, increasing temperature, possible killing fish. Also can reduce level of the water table below the dam, killing plants are trees.\n\n"
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1jeps5 | why people need to be raised and schooled to live well as a person, but my cat, who's not around other cats, knows how to live well like a cat? | Hard to explain. Pets have their instincts that help them survive, why do humans need help in order to live a good life? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1jeps5/eli5_why_people_need_to_be_raised_and_schooled_to/ | {
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"I've written and deleted about 5 starts to this answer.\n\n* animals in the wild teach each other how to hunt and survive - watch anything by David Attenbourough. \n\n* pets don't need many of their instincts to survive - we give them food, we give them shelter. Also, this is why animals from captivity don't do well in the wild. \n\n* in terms of instincts, humans have them - like fight or flight. These things are hard wired in.\n\n* in order to get ahead in the human world, you need money. Money is gained (mainly) by selling your time. We go to school so we can charge more for our time than other people. Animals don't have money, so they need to hunt, build their own shelter etc. whereas we can trade money for these things. ",
"One of the trade offs we made in our evolution for more powerful brains that take up a quarter of our blood supply was that it takes us longer to come online. Our brain starts as a plastic bin of parts that grow together and adapt to our culture as well as the tasks we demand of it to live in a society. As our society progresses, this changes and we need to change how the brain is programmed to keep up with those changes to be successful. ",
"You pretty much answered it yourself. Cats have instincts. These instincts are to eat, hunt, play, ect... \n\nYou have the same instincts more or less. A baby knows when it is hungry, even if it can't express this in words it knows to cry.\n\nAs an adult, humans live in a society which we created so we have to be taught how to fit in. Society changes very quickly (on a evolutionary time scale) so humans don't have time to evolve instincts on how to be an engineer or doctor.\n\nOn the other hand, we have evolved social skills and social instincts that help us fit into a social lifestyle, just like many other primates. Just one example of naturally living well as a person is our sense of empathy.",
"Our pets *do not* have instincts to help them survive. A domesticated animal will have a hard time surviving in the wild. Likewise, a feral animal makes a shitty pet. \n\nDomesticated animals have been bred to be dependent on the owner. My cat does not eat unless I buy her food. She does not shit unless I clean the litter box. Not exactly instinctual. \n\nThe rest is beyond explanation because it is silly to compare a human being to a housecat in terms of intellect and cognitive ability. \n\nEDIT: Humans are capable of relying solely on instinct to survive. But survival mode and living \"a good life\" are polar opposites.",
"This isn't very true. My dog hasn't had another dog to play with in years. She is socially awkward. She freezes when she sees most dogs. It's like she forgot their language. She'll smell their ass but won't let them do the same.",
"We don't live like humans anymore.",
"Cats have 95% firmware, 5% software. \n\nHumans have 75% firmware, 25% software.\n\nThe extra software that humans have is language and culture. These take a lot of time to program.\n\n",
"Animals can learn, but it is not by learning that they become dogs, cats, or horses. Only man has to learn to become what he is supposed to be.\n -Eric Hoffer\n\nJust a nugget from one of my favorite philosophers.",
"In short it's because most humans don't behave like humans.\n\nTribes in Africa (or wherever) that would cut your head off, rape your wife and daughter, and then eat the lot of you without a second thought? That's humanity. \n\nEverything else is cultural training.",
"It's our survival mechanism! I'll explain. \nWe can't hunt with teeth and nails alone, we hardly have any. We're not quick enough to chase a rabbit. Our skin is too thin to protect against those who have teeth and nails. But we've made it this far in evolution, so we must have found some way to adapt, right? Yup. \n\nHere's what we do instead of all that: we're born while our brains are half developed (so the physical stuff is formed at least) but the rest of the brain development happens AFTER we're born. That means we don't have a cat's instincts. How does this benefit us? It means that WHEREVER on the planet we happen to be born, *we can adapt to that region and thrive in it.* Our habits aren't set in stone so that we can make habits that let us kick ass in a variety of situations.\n\nThis development solidified roughly around the Ice Age when we started having to walk to find food, which meant walking upright, which means tighter birth canal and a smaller head that can come through this birth canal - smaller brains at birth. \n\nSo your kitty can survive well - only by doing exactly what a cat does, whereas we can survive on a mountain, in the sea, on Wall Street, or in a ghetto.\n\nFeel free to correct me, this is just my version of what I've read as someone who wants to pursue medicine. Hope this helps, OP!"
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1k4fs0 | what the hell is the deal with bronies? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1k4fs0/eli5_what_the_hell_is_the_deal_with_bronies/ | {
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"They are fans of the show My Little Pony, similar to how Trekkers are fans of Star Trek and Browncoats are fans of Firefly. "
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1nbr7b | why is it called "surfing" the web? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1nbr7b/eli5_why_is_it_called_surfing_the_web/ | {
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"Language left over from channel surfing on TV.",
"The internet is a series of tubes, thus it can be described as tubular. Tubular is an expression that was common among surfers in America during the 1980s. Case closed.",
"because it makes you wet",
"\"going net-surfing\" was coined in a June 6, 1991 comp.admin.policy post by Brendan Kehoe. \n\"...Here's a question: how do other people deal with users that they *think* \nare doing no-nos around the net? One of our users had the habit of \noccasionally going net-surfing and doing the hit-and-run type of \nattempts (trying 'guest' usually)...\"\n\nHe is known for authoring Zen and the Art of the Internet published back in 1992 as well."
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60xctc | what is poison? | Why does bug spray not kill humans? Why can some animals endure things that would kill humans? Does gasoline or bleach or overdose of medication kill you by the same mechanism as cyanide or strychnine or the 'vegetable alkaloids' from old murder mystery books? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/60xctc/eli5_what_is_poison/ | {
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"Really, a poison is something that will harm or kill you if taken into your body in an amount you're likely to encounter. Technically, water or caffeine (or anything) will kill you if you take enough of it, so that's why I added the \"in an amount you're likely to encounter\" part of it. \n\nSince your body is really just a very complicated series of chemical reactions all going on, there are lots and lots of ways to throw a wrench into things and, well, kill you. cyanide or carbon monoxide, for example, bind incredibly strongly to your blood cells and prevent them from carrying oxygen to your cells, starving them of energy.\n\nStrychnine binds to receptors on neurons that normally are for neurotransmitters. In particular, it causes your neurons to be triggered to go off more easily, which causes muscle spasms and death by asphyxiation.",
"A poison is a substance that causes negative physiological effects in an organism. The effects can be disruptice, harmful or even deadly. What makes something poisonous to an organism depends on the substance, the dose and the underlying physiology if the organism.\n\nFor example Grapes are harmless to humans but in cats, they will cause kidney failure."
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n63ht | why are there so many different electrical outlets in this world? | I just found [this](_URL_0_) on 9gag and was wondering. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/n63ht/eli5_why_are_there_so_many_different_electrical/ | {
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"I would say because there are so many countries. Theoretically, a mass summit could create a universal wall plug that countries could then opt into, but no one really has any incentive to do that. The economy will barely benefit from such a change, and might even take a dip, because all the people selling wall plug conversion kits will be out of a job. It's a wonderful idea in theory but only benefits end users. It's just like how cell phones have their own dongles everywhere, because each phone set manufacturer doesn't have a large enough incentive to conform to any standards",
"The Danish plug continues to look happy, while the North American plug continues to look stern and disappointed.",
"I would say because there are so many countries. Theoretically, a mass summit could create a universal wall plug that countries could then opt into, but no one really has any incentive to do that. The economy will barely benefit from such a change, and might even take a dip, because all the people selling wall plug conversion kits will be out of a job. It's a wonderful idea in theory but only benefits end users. It's just like how cell phones have their own dongles everywhere, because each phone set manufacturer doesn't have a large enough incentive to conform to any standards",
"The Danish plug continues to look happy, while the North American plug continues to look stern and disappointed."
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1e0ydd | why is there so much media attention on the jodi arias case? | There has been some sort of coverage about it for weeks now. Why do so many people care about it? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1e0ydd/eli5_why_is_there_so_much_media_attention_on_the/ | {
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"America loves a killer. Bonus points for being a freak in the sack.",
"Attractive white girl + violent crime = media frenzy",
"My mother has kept me up to date with everything. It's fascinating to watch her behaviour and the theatrics of Martinez. I'm glad it's almost over. I'm sure it really boosted HLN'S network ratings, and they're probably scrambling to find something new to entertain viewers.",
"A pretty white girl who we got to see naked might get sentenced to death. ",
"You know what, it's so funny - I read the newspaper every single day, get news delivered to my e-mail, all of that stuff. And if someone put a gun to my head before maybe a week ago, I'd *never* have been able to say who she was or what she did. I have absolutely no idea how I missed the story. I feel like I'm the only person in the world who didn't know what the case was. It's like, what rock have I been living under? And then I see posts like this and discussions around the internet asking why there's so much attention on it, and my discomfort grows even worse.\n\n\nThe point is, people may care, but apparently not enough to make it sink into *my* thick skull."
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4uaj4w | what exactly causes the sickly gross-tasting burps that occur after overeating? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4uaj4w/eli5what_exactly_causes_the_sickly_grosstasting/ | {
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"A pocket of air is always present in your stomach (and visible on a standard chest X-ray).\nWhen eating, some more air gets in through swallowing.\nThe stomach doesn't immediately empty itself when eating, so imagine all you have eaten starting to be digested by stomach acid and enzymes and floating in what you've drunk.\nSo, the air in your stomach normally comes out with burps, but it stayed in this bag full of nasty stuff for a while, so it takes its smell up and out.\nIt actually smells like vomit because it is vomit, it just doesn't come out.\nYou're welcome.",
"I think you're referring to sulfur burps, where it smells/tastes like rotten eggs?\n\nThey can happen for a number of reasons. Stomach infections can cause it, as can food poisoning. Or it can just come from eating a lot of fatty food."
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35cyo2 | why do my hands get clammy when i am afraid? evolutionarily shouldn't i increase my grip ability rather than losing grip with moisture? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/35cyo2/eli5_why_do_my_hands_get_clammy_when_i_am_afraid/ | {
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"When you're afraid, your body's processes speed up, especially ones that help you deal with stress. Most important in regulating your body under stress is temperature regulation, which is primarily handled by sweating.",
"I always remind people: evolution is a c- student. Evolution processes do just enough to help that species \"pass.\" ",
"Don't know why your hands get clammy in the first place, but clammy hands isn't as bad as you'd think.\n\nDamp palms are really only a slippery problem when you're using very wet palms to grip artificially smooth surfaces like metal. On most surfaces, such as dirt or wood or unpolished rock, slightly sweaty palms are actually stickier. ILLUSTRATIVE EXAMPLE: Run your hand on your forearm right now: if you're dry, your hand will slide smoothly. Now think back to a time you were a little sweaty: remember how disgustingly clingy your skin felt? Same deal.\n\nIt basically has to do with the hydrogen bonds in water. For example, adding a bit of oil to your hands will never* (*never say never) make them stickier, but adding water can. On natural/rough surfaces, the water can fill in the gaps between the object's texture and your skin texture. The water then kind of acts as a sealant and a glue, since water is naturally \"clingy\" due to hydrogen bonds.\n\nNot a very strong glue, but it can be effective enough. For example, \"damp palms\" is essentially the mechanism used by tree frogs for climbing. _URL_0_\n\nAlso, feel free to check out _URL_1_"
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2mckub | how is blackberry still in business when no one uses one? i don't know a single person who still uses a blackberry. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2mckub/eli5_how_is_blackberry_still_in_business_when_no/ | {
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"How many people do you know? Let's be generous and say 500.\n\nThat's a rounding error on the population of the US. So your circle is probably not a great indicator.\n\nThere are a number of companies, organizations and agencies that had longstanding contracts with Blackberry. Many of them are working off those contracts as we speak but (for the time) they are still using them. \n\nIn addition, there are some number of people who prefer Blackberries. My understanding from them is that the physical keypad is a plus in their eyes.\n\nStill others haven't upgraded their phone in years because they either A) don't care too or B) don't feel like paying for it.\n\nSo Blackberry is hanging on by its fingernails... but it is still a company.",
"Blackberry is pretty big in foreign markets, and they have a lot of other innovative patents. Their patent portfolio is estimated between $2 billion and $3 billion",
"because people still DO use them. much of the corporate world, which is slow to change standards, standardized on them and is not about to throw out their blackberry enterprise servers and buy hundreds of new phones.\n\nmany have, but there is still a significant amount of holdouts out there.\n\nthey did damn near go under not to long ago, but found investors to keep them afloat.",
"Believe it or not in Latin America it's still very popular ",
"Pretty sure a lot of government agencies use them because of their security features."
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8qvg94 | is there an architectural advantage to “the pentagon” building being shaped as a pentagon? like does it provide more security, or is it simply for aesthetics? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/8qvg94/eli5_is_there_an_architectural_advantage_to_the/ | {
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"It would be cool if there was an amazing architectural advantage to the shape. The truth, as truth often is, is spectacularly boring and ordinary.\n\nThe simple truth of the matter was that the land that the government purchased for the new military headquarters was [pentagonal in shape.](_URL_0_) The building was designed to make the most use out of the land.",
"It's a fascinating story. The book Pentagon a History by Steve Vogel goes into it in detail. The idea was to build a building for the War department with a lot of square footage without exceeding the low building height limits of the District of Columbia. The original location was a rectangular space with one corner cut off by a river. They made plans for this location, essentially a building that completely covered the lot. Then they found that the ground wasn't strong enough to hold up the building. They moved locations, to the present site, and wanted to make up the time. Since the plans for the other site had: chunks of building that were straight, chunks of building that met at a 108˚, and chunks of a building that met at 90˚; they asked what shape could they make without redrawing those plans. It turns out you can make a regular pentagon shape that has more area inside than a square shape. Those are essentially the only shapes you can make without drawing plans for a different kind of corner. So, they reused the shapes to make the present building.",
"The original location was the [Arlington farms](_URL_0_) that is like a uneven pentagon and size limitations for the building so it had the shape of a uneven pentagon. The Arlington farms is today a part of the Arlington National Cemetery.\n\nThe location was changed and the size was not limited the same way but the same planes was used because it was during WWII and it was needed as soon as possible.\n\nThe design had som limitation like 4 floors so not to block the view and steel used was limited and it had to be a quick build.\n\nIf you look at [this image](_URL_1_) you can see the if exactly in the original location.\n\n\n"
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5bnutf | how are amazon third-party book vendors able to offer new and recently-published books in "new" or "like new" condition so quickly? | A book's publication date was set for today, Mon. Nov. 7th. Third-party booksellers on Amazon have already started selling the book for a few dollars below the Amazon price for the book, in new / like new condition. How do they do this? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5bnutf/eli5_how_are_amazon_thirdparty_book_vendors_able/ | {
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7
],
"text": [
"In general, many third-party booksellers on Amazon used automated programs to handle their inventory. Some of them simply have the computer programmed to update when they receive new inventory, and thus those booksellers may have received their shipments of that new book today and thus immediately updated their listings on Amazon accordingly.",
"Some of these sellers are actual bookstores (on the street or online). They get access to new books from the publisher at the same time Amazon does.",
"They are lying about availability, and I can (kind of) prove it with a simplified example.\n\n[This](_URL_0_) is an Amazon link to a manual for a calculator app that's available for Window. I'm very familiar with it because I wrote both the app and the manual. According to Amazon, there are 3 used and 8 new ones available from third party sellers.\n\nExcept that exactly zero copies have been sold. There are no used copies available anywhere in the world.\n\nThe other sellers are pretending to have stock, but they don't. If you order from them, they will simply buy a copy and send it on, adding their own handling charges as a way to make money.\n"
]
} | [] | [] | [
[],
[],
[
"https://www.amazon.com/BC-BASIC-Reference-manual-tutorial/dp/1517450675/ref=sr_1_1"
]
] |
|
47e7wr | why are most cities "downtown" sections really shitty when they're usually a popular | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/47e7wr/eli5_why_are_most_cities_downtown_sections_really/ | {
"a_id": [
"d0c9mcl"
],
"score": [
2
],
"text": [
"Maintenance of a downtown area is a tremendous undertaking. For example, repairing the streets could mean closing down the street for days and days. Colossal traffic jam, redirecting bus routes, businesses on that street pissed off, etc. It's very expensive and difficult. Due to the location, it gets tons of car and foot traffic so maintenance is needed more often. With millions of people going through the downtown area throwing trash everywhere and generally be slobs, there just isn't the ability to pick it all up. Uptown neighborhoods generally are kept much nicer."
]
} | [] | [] | [
[]
] |
||
2lmde9 | why, when i eat terribly (pizza, cookies, chips, beer, etc) can i eat a lot, but when i clean diet, i get so full and 2k calories is hard to get each day? | Srsly--I can put down 1.5 Little Caesar Hot-n'-readies and a sixer of Coors Lite, but now, after 3 weeks of clean eating, 1 gallon of water a day, and exercise 4 times a week, getting my 2,000 calories is SO filling and eating takes WORK.
< ---'Merican | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2lmde9/eli5_why_when_i_eat_terribly_pizza_cookies_chips/ | {
"a_id": [
"clw4s91",
"clw92b5",
"clw9lnh"
],
"score": [
2,
7,
2
],
"text": [
"Define \"clean eating.\" I know a lot of people that cut back on junky, carb-heavy foods and are much less hungry. It has to do with your insulin spikes and resulting hormone suppression (leptin mostly) that keeps you from being mega-hungry. Also, if you're replacing your diet with lots of vegetables, they are much less calorie dense than junk food, so you are also getting physically full on less calories.\n\nEdit: spelling",
"**Caloric density** (the ratio of calories to the weight of the food). \n\nCarbohydrates have around 4 calories per gram; proteins also have around 4 calories per gram; and fats have around 9 calories per gram. \n\nWhen you eat \"clean\" foods, you are generally eating foods that have a low caloric density, but that is not all. These foods often also contain a higher amount of fiber, which increases the feeling of fullness (this is called *satiety*). These \"clean\" items are usually less processed foods containing unrefined carbohydrates, which take a bit longer for your body to digest. This means you feel fuller for longer.\n\nWhen you eat \"dirty\" foods, you are generally eating foods that have a high caloric density. These foods are often heavily processed with more refined carbohydrates, meaning your body can digest it quicker. That means you don't stay full for much too long.\n\nSometimes we mistake the feeling of thirst for hunger, and eat a snack when we could've been satisfied with a glass of water. The next time you feel hungry, try drinking a full glass of water and waiting a few minutes. You'll see that sometimes it's just thirst.",
"A lot of it is evolutionary - back before commercial food production, high-energy fats and sugary carbs were very difficult to come by and encouraged you to eat as much of them as possible. How? They tasted great, and still do. \n\nWe haven't evolved enough for our body to tell us 'stop, that's enough' because the more weight we put on, the less the consequences were of not knowing where our next meal came from. "
]
} | [] | [] | [
[],
[],
[]
] |
|
2bm2xo | is there a possibility in the future for full immersion virtual reality gaming? | I'm very excited about the Occulus Rift but it got me thinking and I began to wonder if there was a possibility for VR gaming that is fully immersed (you have sense of sight, smell, touch, etc).
Sort of like you would be able to log in and just sit down in a chair for a few hours but in the VR you would be fully functional. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2bm2xo/eli5_is_there_a_possibility_in_the_future_for/ | {
"a_id": [
"cj6nboo"
],
"score": [
2
],
"text": [
"Anything is possible, someday, as long as that thing doesn't violate fundamental physical laws. And even then, who knows.\n\nPractically though, yes, this is reasonable some day. One of the critical aspects here for experiencing this \"just [sitting] in a chair\" is the ability to plug our brains directly into computers.\n\nThis is still a very new thing, but we're getting better at it all the time. Cochlear implants (_URL_1_) do this, and there's a ton of new research that's very promising on doing stuff like plugging limbs directly into our nervous systems (_URL_0_).\n\nOf course, none of this is even close to providing a fully realized experience through a wire, but we're starting to make the first baby steps on that path.\n\nAlso, this is a work of FICTION, but if you find this topic cool I highly recommend the book Ready Player One.\n\nEdit: Some links."
]
} | [] | [] | [
[
"http://www.wired.co.uk/news/archive/2013-05/31/darpa-touch-sensitive-prosthetic",
"http://en.wikipedia.org/wiki/Cochlear_implant"
]
] |
|
2hjvzf | why can't we make a system similar to a human body that gets energy from food? | For example instead of running cars on gas, we would put cheese and bread in the car to run. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2hjvzf/eli5_why_cant_we_make_a_system_similar_to_a_human/ | {
"a_id": [
"cktbxx1",
"cktc1es"
],
"score": [
2,
2
],
"text": [
"We could do that. We don't because it would be horribly inefficient compared to the fuels we already use, or most of the alternatives we've already devised.",
"They exist already. They're called horses.\n\nIn fact, the reason the term \"horsepower\" came to exist was because some of the first steam engines were intended to replace horses that were being used to drive pumps to get water out of coal mines. And they *did* replace them, because even the 18xx steam engines were better than horses."
]
} | [] | [] | [
[],
[]
] |
|
a1b9x0 | how does online banking work without the exchange of actual money? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/a1b9x0/eli5_how_does_online_banking_work_without_the/ | {
"a_id": [
"eaoac3n",
"eaoanyv",
"eaob8af"
],
"score": [
4,
2,
5
],
"text": [
"When person A pays person B, the bank takes money out of A's account and deposits it in B's account.\n\nIf they use two different banks, the banks cooperate through a very elaborate digital money transfer system.",
"Most (if not all) banks don't keep everyone's full accounts available in cash; a lot of times they invest it into expanding their business and infrastructure or in various markets to make the money grow. So when the new bank \"receives the money\", it's still on their books, but they don't necessarily physically have it and don't physically need it. ",
"Most money is never actually physical money. When you get paid direct deposit, your money is not physical cash it just stays electronic. It’s just a number on a screen with codes and data that keep it secure and correct. Only when you choose to take out cash does your money become physical legal tender that you can touch or carry in your hands."
]
} | [] | [] | [
[],
[],
[]
] |
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