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3i0eym | why do "million" and "millennia" sound the same, but one refers to millions and the other refers to thousands? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/3i0eym/eli5_why_do_million_and_millennia_sound_the_same/ | {
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"text": [
"Both derive from the word 'mille', thousand. But million refers to thousand thousands, whereas millennia refers to thousand years, or 'mille anni'."
]
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[]
] |
||
d9v7pp | why can't we put a metallic grille on plane reactors to keep birds from getting to the engine? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/d9v7pp/eli5_why_cant_we_put_a_metallic_grille_on_plane/ | {
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"We can’t do this because if a bird we’re to hit the grille and damage it, it could cause more damage as the grille will become entangled in the engine.\n\nMost engines only take ~20% of air through the core of the engine, everything else is bypassed and creates thrust",
"There are a few reasons why this is impractical. \n\nIt would cause resistance for air flow. \n\nWould add weight. \n\nIf hitting a bird at high speeds, it would just fail and get sucked into the engine causing more damage than a bird would. \n\nIncreasing the strength to withstand a bird strike would further increase the weight and further reduce air flow. But bits of bird would still get through and sucked into the engine.",
"That seems like the easiest solution, actually. But there's a problem:\n\nMost passenger planes have a cruising speed of ~800km/h. If just about any kind of bird, no matter if it's a goose or a pigeon, hits a metal grille at 800km/h, it will just be shred into pieces that then still get into the engine. Even if you make it very fine, which you can't because it will become too heavy and restrict air flow, bits of bones will still go through and damage Parts in the engine."
]
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vsvsx | why are the trees still standing with green when the homes are charred? _url_0_ | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/vsvsx/eli5_why_are_the_trees_still_standing_with_green/ | {
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"text": [
"The level of moisture in living trees is much greater than that of lumber and other building materials."
]
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"http://i.imgur.com/s5qGo.jpg"
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[]
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bhnubv | if cameras can take videos with fps equaling single shutter speeds, why do photographers take dedicated still shots instead of video recording everything and later just isolating single frames for “photographs?” | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/bhnubv/eli5_if_cameras_can_take_videos_with_fps_equaling/ | {
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"In some cases you can, but when you take a single frame you have more control over the light. When you take a photo you can balance the depth of field, aperture size and iso- getting the right ratio of the three can give you much needed control in certain scenarios. When you record video- most of those settings become automatic so a lot of work might be needed in post production to get the shot you need. \n\nI’m sure with more expensive technology you can do it easier, but basically the needs for photos and video are not the same to produce an image.",
" > If cameras can take videos with fps equaling single shutter speeds, \n\nThat assumption is not correct.\n\nThe shutter speed is the time the sensor is exposed to light not the time to read out the captured information. A simple camera can capture image in 1/1000 of a second but that do not in any way mean that it can take 1000 pictures per second. It take time to read out the images from the sensor so you talk of single digit number of images per second for most camera.\n\nCameras cant take video at a high fram rate in the same resolution as they can capture a still image. It take time to read out the image from the sensor so you have framerate vs resolution limitation for a sensor\n\n4K video is 3840 \\* 2160 that is only 8 mega pixel and 1080P is 2 mega pixel\n\nFor example a Nikon D7500 DSLR with a 20 mega pixel sensor can do 4k video at 30 FPS and 1080p at 60 FPS but at 20 mega pixel it can only do 8 fps and if you put it in continuous mode it will do that.\n\n & #x200B;\n\nA more expensive and complicates setup might be able to capture 20 mega pixel at 30 FPS but than is also can do 4K at higher FPS. \n\nSo filming video at the same resolution as a still image is simply not at cost efficient. Burst more or continus mode is avalible at the camera and they produce images as fast as posslible and that is a common way take pixture"
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ai4cnu | how do large companies send bulk letters? | For example, when the bank mails me my statement every month, how do they handle the process of printing the statement, putting it in an envelope and mailing it? Is there an assembly line for outgoing mail? Please help me understand! | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/ai4cnu/eli5_how_do_large_companies_send_bulk_letters/ | {
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"I worked at a company where I spent one whole week with just printing letters (I had data from excel worksheet), putting them into envelopes and then bringing them to post office. I had to take one colegue with me, because every day, it was like 60 kilograms of envelopes. \n\nSo it’s mostly repetitive boring work someone has to do for slave-grade paycheck."
]
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[]
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|
4pdk2x | how does the sit in that is going on in the house of representatives work? | What is the purpose of a sit in and how does it work? Does the house have to do anything in response or can they ignore it until they stop? Please don't comment with your opinions on the sit in, just the way it works. Thanks :) | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4pdk2x/eli5_how_does_the_sit_in_that_is_going_on_in_the/ | {
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"In the civil rights movement, sit-ins were very popular. Another word for it could be incompetence, but not in a bad way.\nWith these people, they are basically saying that they will not leave the floor until a bill is passed to increase gun control. The house cannot continue with a normal session until they leave, so they will either need to pass a bill, or get nothing done.\nIn the civil rights movement, people would sit in restaurants they weren't allowed in for hours until the servers would \"give in\" to them and serve them food.",
"The House is in recess right now (could be wrong though) so the representatives there are basically sitting in protest and to draw attention to their cause. The House can go ahead and try to put a bill to vote or they could convene in another location if the Speak of the House decides to. That is in the procedural rules I believe",
"The house doesn't technically *have* to do anything.\n\nThe politicians sitting in don't technically have anything to barter with other than public image (which regarding the 2nd and 5/14th amendment, people's opinions are more or less set in stone) and the annoyance level of those wanting it to end. Think of it like a filibuster, but with more than 1 person.\n\nThe people trying to stop the sit in are trying a few things, like cutting cameras to try and cut down on exposure."
]
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1qi4fn | how do polygraphs work. | And how to trick them ;) | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1qi4fn/eli5_how_do_polygraphs_work/ | {
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"They detect abnormal changes in heartbeat, blood pressure, etc. They prime these machines by asking you simple questions (like, \"what is your name?\") to see how you react when telling the truth. Theoretically there should be physical results when you lie that you have no control over. Problem is that some people may just get nervous when asked certain questions even if they aren't lying. I guess don't feel anything when answering a polygraph? If you don't have an emotional reaction it wouldn't detect any abnormal changes in your heart beat etc."
]
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42hl8t | what are eyeballs doing when looking at autostereograms (magic eyes) and why can some people not see the hidden image? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/42hl8t/eli5_what_are_eyeballs_doing_when_looking_at/ | {
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"Typically, your vision is diverging, although some stereograms are designed with a cross-eyed view.\n\nYou are basically tricking your brain into thinking you are looking at something three-dimensional.\n\nWhen you diverge your eyes, you are focusing them at a point *behind* the paper. Normally, this results in whatever picture you are looking at to simply be distorted and look like nothing (you would see a double-image of the picture overlapping itself) except that stereograms are specifically made so that when both of your eyes are focusing at a point behind the picture, the two double-images overlap in such a way to trick your brain. The differences between what your left eye and your right eye are used by your brain to interpret depth, since usually that's what happens when you look at some three-dimensional shape. Try looking at something three dimensional and repeatedly closing your eyes and opening just one eye and then just the other; you will notice you see two slightly different things. Stereographic images create the illusion of depth due to having each eye see something slightly different, but in such a way that the image can be interpreted as three-dimensional instead of just two overlapping images with no depth, which is what you would see if you tried the same with an ordinary painting, for instance - even though your eyes see two different images, the images are just *too* different, and your brain instead interprets that as your eyes focusing improperly which just gets you to look at it normally.\n\nSome people have trouble relaxing their eyes enough to look through the picture in the first place, and others have difficulty maintaining the illusion due to their brains having a tendency to snap them back to the more \"normal\" way of looking at the image, but I don't think there are any people who are actually incapable of ever seeing such images.\n\n",
"I can't see them... but I can't see in 3D either. I had lazy/crossed eyes as a kid and apparently my brain learned to only 'see' out of one eye at a time. Always wondered why I sucked at sports (catching a ball, etc), wasn't until I had my eyes checked years later the dr was like oh yeah you can't process 3D..",
"When they first came out, I could never see them for love or money. I used to get proper angry with people as they would always say 'you're not doing it properly, you need to look past it and cross your eyes a bit'\n\nI gave up. But recently people in work were doing loads of them and someone suggested looking at some object just past it and then looking at the picture. I can now see the pictures."
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30il3l | the sounds a computer makes when downloading | What are those sounds made by computers when we download things and where are they coming from? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/30il3l/eli5_the_sounds_a_computer_makes_when_downloading/ | {
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"Downloading data is silent. What you're likely hearing is the sound of the hard drive writing the data to disc. For old HDDs (not newer SSDs), the data is stored on magnetic platters and read/written by a read/write head at the end of an articulated arm. The movement of the arm along with the spinning of the platter allows the read/write head to access every location on the platter. Both the arm and the platter make noise when they move, but the arm is by far the noisiest, making a rapid clicking sound as it sweeps back and forth over the platter."
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3ddafb | why is there such racial tension between australian aboriginals and australians? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/3ddafb/eli5_why_is_there_such_racial_tension_between/ | {
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"After taking the land, killing the bulk of indigenous Australians, forcibly removing their children, systematically destroying their culture, then dragging them into an English style European society which we then excluded them from actually taking part in. They had a few good reasons not too like 'White Australia'.\n\nFLIPSIDE\n\nAfter bringng indigenous Australians into the modern era, giving them a new conservative society, healthcare, education, religion, common language and monetary system, they seem a little ungrateful.\n\nReally though, it's a little different in our younger generations, old school Australia is very racist though.",
"Australian here, the short answer is that it's complicated.\n\nMany Aboriginal people are in lower socioeconomic groups, especially those living in regional Australia. To combat this the government offers many programs and benefits to Aboriginal Australians, which causes a degree of resentment from other Australians, however this occurs in many countries where \"affirmative action\" is in place.\n\nThere are some Aboriginal people who take advantage of the government programs, they tend not to work and drink heavily. This lifestyle is unfortunately often passed down to Aboriginal children. Non-Aboriginal Australians resent that their tax-dollars are going into government programs which fuel this sort of behavior. Note that while some non-Aboriginals also exploit government programs it is generally much easier to do so as an Aboriginal.\n\nFor many older Australians there is tension regarding the portrayal of historical events involving Aboriginals. For example in Australians schools children are taught about the stolen generation where Aboriginal children were forcibly removed from their families to be educated by the state. Some older Australians claim that the parents of the children who were forcibly taken belonged to unfit parents (alcoholic or homeless), and that many Aboriginal parents gave up their children. Of course the truth in the matter is lost to history, so this will remain a source of tension.\n\nOn top of this, due to the events that have occurred, many Australians find it difficult to celebrate and acknowledge the achievements of Australian colonists and pioneers without attracting criticism from Aboriginal groups. In contrast it is often required or expected to acknowledge the Aboriginal history of locations at public gatherings. Again this tension is highest in some regional centres of Australia which have rich histories from both before and after colonisation.\n\nUltimately the vast majority of Australians are opposed to any double standards, due to historical and socioeconomic reasons Aboriginals can attract special status more often than other minorities, which results in particular tension."
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4ijpr8 | why people say a college degree now is worth a high school degree from x years in the past? | Does it have to do with content, quality, or quantity of people with a degree? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4ijpr8/eli5_why_people_say_a_college_degree_now_is_worth/ | {
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"No, it has to do with how many people *have* college degrees.\n\nI don't agree with the sentiment as a whole, but I can at least understand the logic of it.\n\nA few decades ago, fewer people went to college. You could get a good job out of high school, so college wasn't as important. Since then, a lot of those high school degree level jobs have gone overseas and the jobs that replaced them often require a college degree. So now your average person likely has a college degree because they need one to get a decent job.\n\nThus, a college degree today is \"worth\" the same as a high school degree from years ago because it is the minimum level needed to enter the work force in a lot of industries.",
"Entry level jobs that use to only require a high school education are now requiring a bachelors degree. So it is worth the same because it is what is needed for the average citizen to get a minimally decent job. ",
"College used to be unusual. For most people, high school taught all the advanced learning that was needed for functioning in society, having a job, running your own business, being a citizen, etc. College was for the really bright people who wanted to be in a learned profession or other fields demanding extra education.\n\nBut then employers started using a college degree as shorthand for intelligence and diligence. In the U.S., employers weren't allowed to use I.Q. tests for hiring, but you had to be smart to get into college and graduate, so that diploma became a useful substitute.\n\nAt first, this mattered to jobs of some responsibility, where one might be expected to manage or run things during one's career. But as demand for \"white collar\" jobs in general increased, the college degree became a basic requirement to even be considered.\n\nWhere once a high school diploma had been all you needed to get a decent white-collar job, now the college diploma was needed. And that's why people say a college degree is worth what a high school degree used to be worth. \n\n(And now the professional roles for which a bachelor's degree was once sufficient now require master's degrees or even doctorates. PhDs, for example, were once so rare as to be remarkable, and only granted to those who truly advanced the scope of their field's knowledge. Now they're often granted for doing a lot of academic research into already-known stuff, for being really academic, rather than pushing the limits, and are a prerequisite for getting many teaching jobs.)",
"Years ago (think late 1800's, early 1900's), a 6th grade education was considered \"educated\". You could read, write and do math. That alone would be enough to get you off the farm and working for a respectable company. A college education was only for rich people.\n\n\nLater... WWII or so - a high school education became more popular. You could still get a decent job with a 6th grade education, but you could do even better with a HS education. A college education guaranteed you a good, well paying job right after graduation. Companies would start recruiting people while they were still in college.\n\n\nAround the 60's the whole 6th grade education pretty much just dropped off the map. HS was required. College still guaranteed a well paying job, but getting a job before graduation became less common.\n\n\nOver the past, oh probably 20 years or so, a college education has replaced what a high school education used to be. A HS education is today what a 6th grade education was back in the 50's. A bachelor's degree is what a HS education used to be, and an advanced degree (masters/PhD) is what a college education used to be."
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c2bi0j | when your phone is ringing, why are the electronics around it buzzing? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/c2bi0j/eli5_when_your_phone_is_ringing_why_are_the/ | {
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"I don't think that's what OP is asking. You can have a phone on silent, sitting next to other electronic devices, and you'll often hear very distinct electronic buzzing type noises from the other devices specifically when the cell phone is ringing."
]
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||
eehplg | why does the sunrise continue to get later after the shortest day? | I live in the Northern Hemisphere and have noticed that the sunrise is later today than it was on the solstice. I've tried to get my head around it via [this article](_URL_0_) but still don't really get it, so please can someone ELI5? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/eehplg/eli5why_does_the_sunrise_continue_to_get_later/ | {
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"From my understanding the solar day, the time it takes for the sun to move around the earth is not 24 hours but slightly less or more. We use a full 24 hour clock so they go out of sync.",
"In short: the length of the day isn't exactly 24 hours. It varies between 24 hours and 30 seconds, and 23 hours, 59 minutes and 30 seconds. However for convenience we always use the average of 24 hours. This means that if the sun rises at 8:00, then the next day it will rise around 24 hours and 30 seconds afterwards, i.e. at 8:00:30, and the next day at 8:01, even though it's December and the Sun should be rising earlier and earlier.\n\nWhy does this happen?\n\nBecause of earth's [sidereal day](_URL_1_) and [synodic day](_URL_0_). The sidereal day is the time is takes Earth to complete one revolution around its own axis, relative to the rest of the stars. This time is approximately 23 minutes, 56 minutes and 4 seconds. So why is the day 24 hours? Well, during that time, Earth also moves approximately 1/365 of its orbit around the Sun. So it needs about 4 more minutes to finish a revolution relative to the Sun, so that it faces the exact same direction as the day before. This is the synodic day, which is what we actually use day to day.\n\nHowever, Earth's orbit is elliptical - during the northern hemisphere's winter months Earth moves a bit faster, so it actually needs around 4.5 minutes extra, making the day 24 hours and half a minute long, and during the summer months Earth moves a bit slower, so it only needs around 3.5 minutes extra, making the day half a minute less than 24 hours."
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zyumc | marcus aurelius & niccolo machiavelli | Why are these two guys famous? I know a bit but what were they famous for? What was their famous thing about? What did these two guys? I don't just understand when people say Machiavellian politics etc. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/zyumc/eli5_marcus_aurelius_niccolo_machiavelli/ | {
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"Niccolo Machiavelli was an author; he wrote a book called \"The Prince\", which was written in the form of an instruction manual to a leader of the time. He was explaining about how politicians should manipulate, pay false praise to their superiors, exploit their inferiors, etc. etc. This is what \"Machiavellian politics\" refers to. Ironically, while many people think that Machiavelli actually said that this was what made a good leader, he was actually being satirical and making fun of the present leadership."
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3evc9a | how can you physically see things in a dream, colors and everything, even though your eyes are closed? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/3evc9a/eli5_how_can_you_physically_see_things_in_a_dream/ | {
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"This is a commonly asked question here. Please see several previous postings among [these previous posts.](_URL_0_) If they don't entirely answer your question, you might create a new post with\na more specific question.\n\nTry our handy Search function sometime. :-)\nFor best results in most cases, use 2 or 3 general, common words\nthat refer to the key concepts in your topic.",
"You don't physically see them. You think about them and remember them. You don't physically see them, though. \n\nInterestingly enough, one of the only muscle sets that's not completely immobilized during sleep is those surrounding your eyes. Your brain still responds to its perceived visual stimuli (your memories and dreams) as if it was actually seeing them, causing your eyes to flicker about \"observing\" things, in what's called Rapid Eye Movement, or REM. Your eyes aren't actually seeing anything, but your brain is tricking itself into thinking that they are, thus involving your body in your dream. ",
"When we see things, much more is involved than just our eyes. The eyes receive light, turn that light into electrical signals and then they send those signals via the optical nerve into the brain.\n\nIn a dream, the part of the brain that does the image interpretation just goofs off without input from the eye.\n"
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2zyl80 | why are the bottom of our feet so tough yet so ticklish? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2zyl80/eli5_why_are_the_bottom_of_our_feet_so_tough_yet/ | {
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"You got a lot of nerves on both your hands and feet, you use the ones on your hands to handle things and the ones in your feet to handle your balance, plus checking if you aren't walking over broken glass.\n\nIf you try it, its easy to notice that \"ticklish\" sensation on your hands, thing is, your hand is more used to these finer sensation, while your feet are more tuned for pressure differences, for balance \n\nIn short: Both your hands and feet are ticklish, but you feel it more on your feet because they aren't as used as your hands to these kinds of sensations."
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17tvvg | why do some dogs never stop eating? | Like.. if you gave them unlimited amounts of food, they'd eat until they die. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/17tvvg/eli5_why_do_some_dogs_never_stop_eating/ | {
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"text": [
"In the wild a wolf wouldn't have any idea when their next meal might be. So, overeating when there is an abundance of food will let that wolf build fat which will see it through during times when food is scarce. This instinct has continued on with domesticated dogs."
]
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9mbki5 | why does florida water taste weird? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/9mbki5/eli5_why_does_florida_water_taste_weird/ | {
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"One thing to consider is not all of Florida uses similar water. There is both well and municipal sources, depending on which you got, and how it was treated or can have various different properties such as taste and smell. And well water is usually treated at location, which means system and treatment can vary even between neighbors to produce different results.\n\nOn top of this different counties also get their water supply from different places, which just like above can vary what is actually in the water, and effect how it is treated, which means even with municipal water two cities in Florida can have different tastes.\n\nLastly is subjectivity, in which it may also taste weird because it's not what your use to, while locals may not notice it."
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60estn | what would actually happen if you were ejected from an airlock into outer space without a space suit on? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/60estn/eli5_what_would_actually_happen_if_you_were/ | {
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"Micheal over at Vsauce does a good take on this.\n\n_URL_0_\n\nJump to 8:30.\n\n...on mobile and cant do all the fancy linking.",
"You would suffocate because there is no air to breathe.\n\nHowever, even if you're rescued slightly before dying, you are still really messed up.\n\nIf you don't close your eyes, the water in your eyes will start to boil due to the difference in pressure so your eyes will dry out. Same thing for the saliva in your mouth.\n\nYou will need freeze instantly, but steadily lose warmth.\n\nYou will get hard sunburn. On Earth, our atmosphere protectes us from a lot of sunlight. In space, you are not protected and will get dangerous burns.\n\nAfter two minutes you will be dead due to a lack of oxygen.\n\nHowever, if you are rescued after a few seconds, you would survive relatively unharmed.\n\nThe closest we ever got to this was in 1966, when NASA technician Jim LeBlanc's space suit had a leak in a vacuum chamber. He lost consciousness after 14 seconds and claims the last thing he remembers before passing out was how the saliva on his tongue started to form bubbles from boiling.",
"The vacuum would drain the liquid from any exposed part of your body. You would quickly suffocate, as there is obviously no air to breathe. \n\nYou would lose heat, but given there is nothing in space to actually conduct heat away from you, this would be far from what you see in fiction where people instantly freeze. To be sure, you would radiate heat out regardless, but it isn't nearly as \"cold\" in a vacuum as an equivalent temperature atmosphere.\n\nYou also would not explode, or anything ridiculous like that. You might have your surface blood vessels begin to get damage if you were outside long enough, but you would be dead long before that.\n\nBecause you would suffocate.",
"All the air would rush out of your lungs, and your ears would be very painful, if your Eustachian tubes were blocked at the time your eardrums would very likely burst.\n\nYour digestive tract would begin to swell up due to trapped gases, and some gasses would begin to leak out of your esophageal sphincter and anus.\n\nAny moisture on the surface of your lungs and other mucous membranes would start to boil off. This would feel chilly, but not cold. EDIT: I was inspired by a comment to do some math, over a minute or two it wouldn't matter much but over a longer period of time you'd get pretty cold. But you be dead so.\n\nDue to the lack of air your lungs would start working backwards and oxygen would start coming out of your blood.\n\nYour body would swell as small gas bubbles started forming in soft tissues, some small capillaries near the surface might burst.\n\nPreviously dissolved gasses would begin to form bubbles in your blood vessels, but your blood would not boil because your blood pressure is high enough to keep the boiling point above your body temperature.\n\nAfter 15 sec enough oxygen would have diffused out of your blood into your lungs that you would pass out.\n\nYour body would continue to swell to somewhere in the region of 2 times your typical volume, at which point your skin would have pulled taut enough to halt further gas formation.\n\n\nYou now have the worst sunburn of your life on whichever side of you has spent the past minute in the radioactive hellhole that is unfiltered sunlight.\n\nAt 1min 30sec brain damage starts to occur. Repressurization anytime prior to this results in full recovery with proper medical intervention.\n\nAt approximately 2min brain damage is extensive enough to be incompatible with life, beyond this point no amount of medical intervention can save you.\n\nEDIT 1: No don't hold your breath, your lungs will burst and you will be extra mega boned.\n\nEDIT 2: Water boils at a lower temperature in space, your body happens to be higher than space boiling.\n\nEDIT 3: We know this cause some poor sap (Jim LeBlanc) mega fucked up by managing to dislodge the air hose on his suit while in a vacuum chamber. For his bravery he earned 87 seconds of vacuum and a bad earache but was otherwise ok. Also some fucked up dudes thought that trying it out on some dogs would be an OK thing to do (another comment further down has the link).\n\nEDIT 4: Omg I get it Total Recall has a scene like this.\n\nEDIT 5: After some questions about the dog tests I have poached the [link](_URL_0_) from u/clocks212 bellow, go show him some love!",
"What if you had a scuba setup, or something like oxygen to keep you alive in space?\n\nEdit: Hey, I know, a space suit it pretty much just a pressurized oxygen setup with some perks like radiation shielding, but I just wanted to know how long you could live with the oxygen taken care of.",
"They've done these tests on dogs in vacuum chambers. They blew up like balloons, but if I remember right if pressure was restored within 90 seconds there were no lasting effects. Longer than that and they died. \n\n/edit why the downvotes? They weren't my dogs. Source _URL_0_\n\n\"But death is not instantaneous. For example, one 1965 study by researchers at the Brooks Air Force Base in Texas showed that dogs exposed to near vacuum—one three-hundred-eightieth of atmospheric pressure at sea level—for up to 90 seconds always survived. During their exposure, they were unconscious and paralyzed. Gas expelled from their bowels and stomachs caused simultaneous defecation, projectile vomiting and urination. They suffered massive seizures. Their tongues were often coated in ice and the dogs swelled to resemble \"an inflated goatskin bag,\" the authors wrote. But after slight repressurization the dogs shrank back down, began to breathe, and after 10 to 15 minutes at sea level pressure, they managed to walk, though it took a few more minutes for their apparent blindness to wear off.\"",
"So I've heard a lot of different things about what the radiation would do to you. Apparently it'd be one hell of a sunburn, but I've also heard that going out entirely unprotected would essentially fry you in a few seconds?\n\nJust how dangerous is the unfiltered sunlight and radiation around earth? ",
"So wait, you don't freeze? I know the vacuum is bad but no one is talking about the lack of heat. ",
"[This](_URL_0_) useful video should help explain the effects. \n\n* All the air from your lungs would evacuate rapidly.\n* Your bowels would evacuate.\n* Your skin would swell up.\n* Your saliva and blood would turn to gas. \n* You would get sun-burnt from radiation from the sun. \n* Your capillaries will burst.\n* After a few second, deoxygenated blood would flow to your brain causing you to pass out.",
"This is by far the most realistic video I can find on YouTube\n\n_URL_0_",
"There's a scene in the most recent episode of the expanse where a guy watched his girlfriend? Get blown out of the airlock. Nothing much happens she just breathes out, looks scared/uncomfortable and dies. I'm led to believe this is pretty accurate. Do not use total recall as a frame of reference.",
"The pressure that keeps stuff in your body goes away, so stuff - gas specifically - boils away. Not because it's hot, but because there's nothing pushing it into your body. That pressure starts at about 50k feet. It wouldn't be explosive. It would be painful, but you'd die when you stop breathing out. ",
"IIRC I think the scene in the incredibly terrifying \"Event Horizon\" where the younger guy is possessed and puts himself out of the airlock is pretty close to what happens. You have a little bit to be retrieved without devastating harm, but several things start happening (like fluids in your body starting to boil away) happening more rapidly the longer you're outside. At least I thought I read the scene was pretty accurate somewhere. ",
"Science fiction seems to state either you will explode, or nothing will happen and you suffocate. Neither of these is correct.\n\nThe first noticeable effect you would observe on someone ejected into space would be flushing of the skin. It would quickly turn red as the blood vessels get closer to the surface. Eventually the larger blood vessels with bulge out. Some may rupture leading to bruising. This is not comfortable. Folks on youtube occasionally stick their arms into vacuum chambers, they claim this is very painful. This may cause the victim to shout, exhaling early.\n\nFurther the victim could hold their breath. The vacuum of space is not so strong as to rip the air from their lungs, but holding their breath would be uncomfortable as well due to the negative pressure. this would provide a brief extension to their consciousness, but they would eventually exhale and begin to suffocate.\n\nduring suffocation the victim may indeed move their mouths open and shut, clutch at their throat, or tug at the collar of their shirt, and look *VERY* distressed. They would eventually fall unconscious in likely under a minute (varies)\n\nWhen they fall unconscious they would enter the fetal pose (knees slightly bent, arms loose, head down, as this is the natural position of the body without gravity or conscious interference. They may spasm once more before death, otherwise they will not move again."
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240zd0 | how come i can smell my fart when i'm running? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/240zd0/eli5_how_come_i_can_smell_my_fart_when_im_running/ | {
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"Because you aren't running fast enough",
"You're on a treadmill."
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25dfih | - if the earth is a sphere, why is north america considered "the west?" | Why is American culture considered western culture? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/25dfih/eli5_if_the_earth_is_a_sphere_why_is_north/ | {
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"Back in the day, if you started from Europe, you see Asia to the east and an undefined amount of water to the west. When we found out there's actually several Americas there the West/East dichotomy had already been established.\n\nAnd overall, USA is extremely similar with Europe in terms of culture. If the Chinese had found and conquered the new world we'd see it as \"East\".",
"Because our culture didn't start in America.\n\nYou could argue that it started in Europe but Europe was heavily influenced by the Romans, which were influenced by the Greeks, and by this point we're pretty much around the north side of the Mediterranean sea geographically speaking.\n\nThis is where map making started and where all of our geographical terms started as well. For all intents and purposes, the center of the world was the Mediterranean. Every naval engagement before the rise of England was there. The brunt of our ancient history and knowledge comes specifically from there. Western culture was typically more of a broad term for civilizations with Roman roots. The western side of the Mediterranean.\n\nEngland is western culture, so is France and Spain. It's become more of an American label because we're even more west than Europe geographically speaking.\n\n"
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s4s48 | why countries sell each other guns | Im confused as to why countries sell each other guns and armaments such as tanks, surely its just a threat to their own security? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/s4s48/eli5_why_countries_sell_each_other_guns/ | {
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"You sell things to other people to make money. For example, the US sells fighter jets to Israel to make money, yet national security isn't threatened because Israel is 1) far away and 2) a friendly nation (to the US). If you have surplus weapons and equipment sitting around at cost, then selling it makes sense.",
"The former USSR sold, or gave, millions of AK-47s to their allies. They did this to strengthen their allies. This sort of thing has happened throughout history.",
"1) Income\n\n2) They are allies protecting their interests. Or, the enemies of our enemies are our friends\n\n3) they're usually low-grade weapons that don't harm us. ie, we sell f14s to Israel. Even if they started war with us, we have f22s that would obliterate them"
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6vk7wl | why are sprouted grains touted as being so much healthier than non-sprouted? | What is it about sprouting the grains that makes them more nutritious? Does cooking make a difference? How exactly does the sprouting change the nutritional profile? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/6vk7wl/eli5_why_are_sprouted_grains_touted_as_being_so/ | {
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"sprouting grains increases the bioavailability of their nutrients. Unsprouted grains are harder to digest. Cooking grains can breakdown certain nutrients into more digestable forms but can also destroy some of the nutrients. so thats a toss up. ",
"The stuff that is in the grain is basically nutrient storage for the plant, packed tightly in a format that doesn't easily start rotting. That makes it difficult to digest - which is the reason we have to cook them before getting any nutrients out of there.\n\nNow when the plant starts sprouting, it converts all the starches into sugar and the protein into amino acids, which can then be used to grow the plant cells. The same process makes them easier for us to digest.\n\nThe plant also produces all the vitamins it needs itself, so they are not necessarily stored in the grain. For example, there is basically no vitamin C in the raw grain, but quite a bit in sprouts.\n\nCooking always destroys some of the vitamins, but it's not a big deal. "
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9h7bjy | what is arp cache poisoning? | Very basic knowledge of computers, networks and associated jargon, so very small words are appreciated. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/9h7bjy/eli5_what_is_arp_cache_poisoning/ | {
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"Every network device has a MAC address, it's just a number, and every network card is built with it's own unique number. When you connect to a network (like your home Network), your computer asks for an IP (an address on the internet). Unlike a MAC, IPs are made in such a way that you can narrow down where to send data based on just part of the address just like how mail says to Bob, 123 St, NY, NY, you can read it and send it to the NY office and let them figure out where in NY to send it, you don't actually need to find Bob's house on a map.\n\nAnyways, things in your home typically sort data just by MAC, they have a list of every MAC on your network (every computer in your home for example), and what wire it's connected through. Now people access stuff with IPs, so when you go online you need to first take the IP, then find what IP it needs to go to (your modem, to get to the internet), then you need to find the MAC of your modem, and then send the data to the MAC. The ARP cache is the list of IP to MAC mappings for all known devices on your network. The ARP protocol is used to allow other devices to tell you their MAC.\n\nARP cache poisoning is a network attack where you just listen on the network for other people's IP and MAC, and then lie and use the ARP protocol to tell everyone actually you have that IP. This will typically cause all devices to then send data to you, even if it wasn't supposed to be destined to you, you then look at it and or change it, and then using your old list of MAC-IP mappings send it to the right destination. This means that you can connect on WiFi on a home Network and see the traffic destined for the internet, even for devices not on WiFi (so you can force wired devices to transmit their data over WiFi for you to see)."
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3ff7tv | why does a scale give different readings when i'm standing, crouching, or on my tip-toes? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/3ff7tv/eli5_why_does_a_scale_give_different_readings/ | {
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"It has to do with the way your weight disperses across the internal plate that's connected to the scale. If you stand on a corner, it's going to affect the way your weight makes it to the sensor, if you crouch with your ass out, your center of gravity is off of center, and the same thing happens. That's why they have a little picture on most scales showing you how to stand and where to place your feet. ",
" Should not. You have a cheap and inaccurate scale. A good scale has multiple pressure sensors in the corners and adds them up, or is designed to move smoothly regardless of where your weight is on the platform. "
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3udxq9 | why do school district have to pay for special aids for students who are deaf or with major disabilities? why not health insurance? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/3udxq9/eli5why_do_school_district_have_to_pay_for/ | {
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"Why should a school pay for health insurance? That's a private decision up to parents and families. They make these videos as it falls within their realm of responsibility to educate children regardless of condition of learning. "
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ctbe29 | assuming they are not shot out if the sky. how long will satellites function without human interaction? what would make them fail? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/ctbe29/eli5_assuming_they_are_not_shot_out_if_the_sky/ | {
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"Usually the limiting factor in sattelite missions is funding.\n\nIf the project stops being funded the sattelite is either deorbitted and burns up in the atmosphere or left dead in space.\n\nIf communications with the sattelite is severed then it will drift for a very long time. However due to different factors sattelites drift lower towards the earth and after many hundreds of years would burn up.\n\nThere are some orbits that a sattelite can occupy where it will never drift however currently there are no sattelite occupying these orbits."
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6mh15t | why does something just smelling/tasting bad make some people physically sick, even though they haven't consumed any of the item in question? | Also the fact that some people are much more susceptible to it than others...
Thanks! | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/6mh15t/eli5_why_does_something_just_smellingtasting_bad/ | {
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"It is something called taste aversion. \n\nBasically, you have smelled something similar to the bad smelling thing in your past and it has done some sort of harm to your body, and your brain makes a copy of that smell so that your brain knows \"If we smell/taste this again, get it away immediately!\".\n",
"It's a defense mechanism. Back before modern food packaging, when our species was young, we hunted and gathered food. If meat was spoiled, or berries were bitter (most likely poisonous), it would smell and taste bad. Our body would reject the potentially harmful food to prevent illness.\n\nOne of the biggest gag inducers is watching someone else throw up. The smell will also trigger a gag reflex. Back when we travelled in groups in the wild, if one member ate something that made them ill, the whole group likely ate that same thing."
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75pvre | how are the bubbles when you spit formed? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/75pvre/eli5_how_are_the_bubbles_when_you_spit_formed/ | {
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"I'm assuming this is referring to when you simply spit on the ground.\n\nWhen you spit you are forcing saliva out of your mouth by mechanical (muscular) forces and also by forcing air out of your lungs. The gases you exhale when spitting do not all dissipate. Some of these gases may become \"trapped\" in the liquid saliva. Since the gases are going to be molecularly attracted to each other they will create bubbles. If you poke out all the bubbles in your spit you'll probably notice only the liquid remains. \n\nPicture cannonballing into a pool with goggles on. You'll see tons of bubbles all around you because your brought them in with you. Except spit holds onto these bubbles, most likely due to its lower viscosity (flow)."
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1jo6dq | liberalism vs socialism | If my understanding is right, socialism and liberalism have similar goals (distribute money democratically, break down private enterprises). However, when I visited /r/socialism, a guy mentioned that liberalism is 'evil'. What are the differences and beliefs of the two ideologies? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1jo6dq/elif_liberalism_vs_socialism/ | {
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"One major difference is that liberals may acknowledge what they consider pragmatic considerations in their lives. It is possible to be a 1% top earning executive, and support social structures which narrow wage gaps. The executive may demand she be paid highly given the value of his specialized work. Yet, she may be also interested in seeing the lower earners in society be paid better.\n\nThere are indeed top paid individuals who vote for President Obama and accept high taxes. They will always want to be paid very well. But won't mind seeing others in society advance by a substantial degree.\n\nA socialist is stringent in the principle of redistributing wealth. They will demand that redistribution be explicitly and principally established. They will be ok if they are paid the same (or only marginally better) as the janitors and secretaries they hire.\n\nTo the socialist, the liberal is a hypocrite and undermines the pressures necessary to effect socialist change.\n\nEdit: interestingly, you'll see a similar reaction by radical capitalists against libertarians. They see libertarians, despite many of the same ideals, as undermining and short circuiting the social tide toward capitalism. Though I doubt capitalists are represented at all on reddit--you'll find they act the same as socialists against liberalism.",
"There is difference between \"Liberals\" and \"Liberalism\".\n\nWhen people talk about a liberal they are talking about someone who have progressive view on social issues. Due to historical precedents these people are often placed on the left-side of the political spectrum, where you also can find among others socialist and after a time they quickly there was an association between made between liberals and socialist, even if the groups had initially nothing in common beyond being on the left.\n\nNow, when people talk about Liberalism, they are talking about a philosophy that supports freedom, including (but not limited to,) freedom of the press and religion, democracy, civil rights, legal equality, freedom of the individual, free trade, and private property. In short, they are not adverse to people making money, private enterprises or anything like that, as long as everyone plays by the same rules. In fact, the idea of private property and enterprise is very important in Liberalism, as it is a way to support and promote the betterment of the individual and society.\n\nIn a way those who support Liberalism are much closer to Libertarians than to Socialists, the main difference being that Libertarians believe in small (or in variants the complete absence of) government, while Liberalism generally does not concern itself with the size of government as long as the government is democratic, and fair.\n\nAs with all things political, of course there are different, variants of each philosophy that make the whole thing harder to define, most of them equally right/wrong and many claiming to be the one true definition.\n",
"Making an assumption you are from the US - apologies if that is not the case. \n\nLiberalism everywhere apart from the US is the polar opposite of Socialism, it's what I think most people in the US would recognise as Libertarianism.\n\nFor some reason the US uses liberal as a bye-word for left wing. No idea why this has happened and it only seems to happen there. If the person who responded to you was not from the US then they were almost certainly using a different definition of the word.",
"Okay, the first thing to understand is that liberalism is not about the breaking down of private entreprises. Far from it. I'm sure someone else can describe that system with better clarity than I can, so I'll try to explain socialism - I am a democratic socialist and I am making no attempt to be unbiased here; I am pretty much only giving the positives of socialism and the real world is not the happy-go-lucky place of a five-year-old.\n\nOkay: ELI5 economics lesson. There are four main 'factors of production' that are used to create goods and services. These are land, labour, capital and entreprise. \nLand is basically any natural resources, be that space to build, space and a good climate to farm, a good fishing ground or a good mineral vein. Anything like that. Back in feudalist times, serfs used to be counted in the 'land' category.\nLabour is workers that can be employed, in return for a wage or salary. Capital is the technology and machinery used to extract and process stuff - so, if I want to get electricity from sunlight I need to buy a solar panel.\nEntreprise is the initiative to put it all together, start a company, lead a team and take on the risk of failure.\n\nSocialists believe that Capital and Land should be owned by those using them, and decisions should be made democratically.\n\nSo imagine that you're five years old and on the first day of school the teacher gets the class together and tells you that you will be doing paper cutting! You have to cut squares three inches by three inches, with straight edges (so no tearing them), and for each square to trade in to the teacher, you get a square of chocolate. You think - brilliant! I love using scissors, and I'm good at it too!\nExcept this one kid rushed into the room and took all the scissors and refused to give them up. Now you can't make anything because you don't have scissors... so you go up to him and ask for a pair.\nHe says \"Okay, but only if you give me half the squares you make.\" So you do - after all, it's the best option available to you at the time.\nSo pretty soon you have a nice little production line going - the paper (land, let's assume this is a non-scarce resource like sunlight, although it is possible for this to be hoarded too) is being ferried from the paper drawer to the drawing table, neatly marked with lines showing where to cut, ferried over to the cutting table, cut into squares, then ferried to the teacher's desk. This is using labour.\nYou even have an 'organiser' who is overseeing the whole thing and making sure that everything is going as well as possible (this is entreprise).\n The chocolates are collected and passed out one each. Except... because of your deal with scissors boy you have to give half of all the chocolates to him, even though he hasn't done anything at all! You tell him it's unfair and to give back the chocolates but he says no, and he threatens to take back all the scissors if you keep asking him.\nSo you go to the teacher (the state) and tell him that scissors boy is being unfair and mean and he shouldn't have control over the scissors just because he got into the room first. The teacher thinks for a moment and then says \"But he does own the scissors. He's letting you use them. You shouldn't complain about it.\" (This is the state upholding private ownership of capital)\n\nSo you continue along for a while and then you suddenly realise that all you have to do is persuade your people at the cutting table not to give the scissors back to scissors-boy. After all, he doesn't have them right there in his hands (your friends do though), and he's not using them. It shouldn't impact him too much, right?\nSo you go to him and tell him that he's not going to get any more chocolates for free and if he wants them then he has to work for them like everyone else. He gets angry. He draws back his fist to punch you...\n...and the teacher steps in and stops him.\n(Normally, this incites a violent and bloody revolution. It all depends on whether the owners of capital have enough influence among the political elite to have the state's army and weapons on their side. It can be also achieved democratically if the state sides with the majority of workers (e.g. if there is a functioning democracy and enough people want the change enough). Different strands of socialism disagree on how the revolution should be implemented).\n\nSocialism is generally pretty tied with the civil rights movement on the left. So is liberalism. Their main disagreement area is that liberals champion free markets and private ownership of capital/land, and socialists champion collective/democratic ownership of capital/land - some socialists disagree with free trade and some support it.\n\nThe fact that the two movements are so close to one another in some ways but so far apart in others means that they come into contact with each other very often having to, say, work together for a goal or being mistaken for the other by people who don't know the difference between the two (and that's why I think it's brilliant that you posted in ELI5 to find out more instead of blindly assuming you know what's what). This is very grating for both sides.\n\nBeyond that, there's the fractionary mentality of the far left which leads to even little differences being blown way out of proportion, best explained in this joke:\n_URL_0_",
"In my theory, Americans have for some reason mixed up the terms \"social liberal\" with \"socialist\". They want a strong government that cares for its people, by monopolising healthcare and so forth, but still allowing for a market economy for everyday goods. A socialist would reject that in favour for command economy that is collectively owned. I'm guessing because of all of the \"Red scares\" and what not, social liberals have been equated to socialists and the term \"liberal\" has been turned in to something pejorative. "
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8arr35 | how did "chinese" food in the u.s. get so standardized? | Pretty much anywhere in the country has the same menu items that come out almost exactly the same way. It's almost like they are all variants of the same chain. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/8arr35/eli5_how_did_chinese_food_in_the_us_get_so/ | {
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"They all buy from the same enormous restaurant supplier, much the same way that so many diners have pretty much the same menus. A big truck brings it all, prepackaged and ready to prepare. It keeps costs down and customers are more comfortable eating food they're familiar with; not everyone is looking for a unique dining experience. Note that not all restaurants do this, but a large number do. ",
"The Chinese Exclusion Act in the 1800s banned Chinese immigrants from doing pretty much any good jobs which drove Chinese Americans to slums. Chinese food was considered dirty and for poor people as a result. The act was repealed during WWII because China was considered an ally. As a result Chinese food didn't really catch on in the US until fairly recently. During this time, the majority of Chinese immigrants to America came from a handful of places in China, most of them ended up in New York, and most of them were illegal immigrants who found work in restaurant kitchens. They adopted their cooking styles to what was locally available, i.e. General Tso's Chicken is just chicken nuggets smothered in sauce. There's a very good documentary on Netflix called ~~General Tso's Chicken~~ The Search for General Tso which better answers your question.\n\nEdit: thanks u/deuce232 for the correction ",
"Training. Newly arrived Chinese immigrants in America typically find that fast food Chinese restaurants are one of the few sources of employment opportunities due to their lack of English language skills and often times, lack of formal education. \n\nSo they start out by working and learning under an established Chinese restaurant. Then they save up some money and move further in-land to start their own Chinese restaurant. In time they will hire other Chinese immigrants who are either their relatives, or perhaps friends of their relatives, and before you know it you got Chinese restaurants in say, South Dakota, serving up the same food as one in NYC. \n\nThey cook the same dishes that the original restaurant in which they worked at cook, because they understand that's what Americans like to eat e.g. General Tso's, Sesame Chicken, Fried Chicken Wings, Crab Rangoon, etc. The menu is basically off a template and again there's a \"standard\" because many of the restaurants use the same printing company. \n\nThere are no \"pre-made\" versions of most of the main dishes: they are simple enough to make from scratch i.e. General Tso's is breaded chicken, stir fried with a simple sauce. However many of the appetizer items are indeed pre-made i.e. crab rangoon, dumplings, spring rolls etc. because they are rather labor intensive. \n\n",
"I recently ordered General Tso and Orange Chicken thinking it has completely different sauces. It tasted the same so I called them back and they mentioned it uses the same orange zesty sauce. The only difference is that one is using dark meat and the other white! Blew my mind.",
"Have a watch of Netflix's Ugly Delicious \"Fried Rice\" Episode 7.\n\nAs others have already mentioned, essentially the cause is racism, population, and wealth. Now that all three factors are hitting a tipping point, at least in metro areas, there is a huge explosion in both the quality and also the variety of \"Chinese\" food.",
"Most Chinese food in the US is Cantonese food. One region of China has come to represent all of China in its cuisine. It's like if Creole food represented all of the US's cuisine.",
"Stop reading these answers and watch the documentary \"The Search for General Tso\". It will answer your question in more depth than anything you read here.\n\nJust watch it. Now.",
"Side hijack question... Why is Chinese food in north america so different from real chinese food yet Japanese food is very close to the real deal.",
"Same as any other food. Part availability of ingredients, part what the rest of us find appealing, and part why reinvent the wheel. Like our Mexican food is mostly tacos, burritos and quesadillas, but they have much more to offer if you actually went to Mexico. And if you were to start a Mexican restaurant today it would be expected that you have at least 2 of these items in some form. As a cook, you don't want to have to cook 50 different recipes every day, so you figure out what sells best and market that.",
"I don't know about America. But the equivalent in Australia is fried rice and spring rolls. Even some more \"authentic\" places have to add these to the menu specifically to cater for the whities who NEVER fail to put this on their order. "
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24ntr8 | how does applying to college work, with paying, scholarships, admittance, and etc. | Applying, if you are accepted, do you go? Financial aid, the entire process. All the fun stuff about college. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/24ntr8/eli5_how_does_applying_to_college_work_with/ | {
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"Its a lot of paperwork, and it varies based on the school.\n\nBut the basics are these -\n\nYou apply to college by filling out an application. Many use the \"Common App\" or the \"Universal App\" but some schools have their own application they want you to use. In either case a quick trip to their website will direct you.\n\nApplying for financial aid is equally easy. You will need to fill out a FAFSA which will cover the majority of your financial aid. This is online and not very hard. Many schools will offer need or merit based scholarships to those who qualify and they will inform you if you qualify. Finally, some scholarships/grants are separate things. For these you will need to (again) go online and find out what the requirements are an apply. \n\nAs with everything else, its almost entirely online and not very difficult. This is a very common road to travel so Google will help you a lot.\n\nTo the question of \"If accepted do you go\" only you can answer that. Its a personal choice."
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a4r4u3 | do people calmly wake up from comas? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/a4r4u3/eli5_do_people_calmly_wake_up_from_comas/ | {
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"I've been in a coma( 2 days) and so have a few of my family members, from what I've seen no, they usually jump up or make a loud gasp, in my case it was screaming.",
"I feel bad for anyone who watched the 2013 YouTube rewind then got into a coma then saw the 2018 YouTube rewind "
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7dvo07 | what does it mean that a city was founded by someone ? | I read often that some great ancient leader founded a city, e.g. the various Alexandria founded by A. the great.
I am unsure what does that entails. For example: from where did the citizens come ? Is it just a matter of saying "this pre-existing conglomerate of abitations is henceforth to be known as Alexandria" ? Or was there an effort to relocate people more or less forcibly from the surrounding region ?
I understand that thing may be different from case to case, so I am after some generic answer. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/7dvo07/eli5_what_does_it_mean_that_a_city_was_founded_by/ | {
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"Practically speaking most founded towns in the old world were already small settlements and generals would add economy to them by basing resupply ports, garrisons, etc there and relocate populations from other conquered regions to make it work. There are some that were completely new though and those were usually chosen for strategic reasons like the confluence of rivers, high vantage points, important resources... Most of the various Alexandrias were renamed preexisting cities.",
"Generally a city is \"founded\" by whoever was in charge when it was decided there was going to be a city there. That can mean that Alexander the Great rolled up on some villages in a nice spot for a port and \"founded\" a city on top of them, or Peter the Great (lots of the Greats here) decided he wanted a new capital and forced thousands of people to die in a horrible swamp building it.\n\nCould also just be whoever lead the pilgrimage/wagon train/etc to a new spot and set up a town.",
"In the 1800s my great-great-etc.-grandfather founded a town in Georgia USA called “The Plains of Dura”, after a site in the Bible mentioned in a story of Nebuchadnezzar. \n\nThe founder was a banker and funded some of the cost from his own purse and loaned some from his bank. The land was previously occupied by native Americans who were forced out by the government. \n\nSo “founded” in this case means, arranged a sweetheart deal on land and then arranged financing for construction of the core of the town. \n\nThe town is now called just Plains, and is famous for being the birthplace of US President Jimmy Carter. "
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e74z4o | how do christmas lights flash individual bulbs? | With most Christmas lights, they have a line of LED's. How do they light particular LED's individually? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/e74z4o/eli5_how_do_christmas_lights_flash_individual/ | {
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"Many are done as an arangement of 3 strings. If you look closely you can see three wires on many strings or icicle lights. If you really look closely, there's never a need for the entire string to be off and a individual bulb lit. You can get away with controlling 33% of the string at a time for it to look random.\n\nIt will iluminate each string independantly and it will look like every bulb is independantly flashing but in reality, every third bulb is iluminating at the same time.\n\nSometimes they switch up the order so its not uniformly every third connected for randomness.\n\n\nSome new light strings have a tiny IC on every light which is really interesting. Power, ground and data is shared for all lights and every single bulb understands a giant string of pulsed numbers and what ID it is and what colour and brightness it should be at. This happens every milisecond or quicker. Believe it or not, these are actually cheaper since the entire bulb and silicon processing core is integrated and produced in the billions without manual labor."
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4olrp0 | what is the point of image-based captchas if there are already lots of bots that can solve them? do ticket-reselling websites have some secret ocr/high performance photo recognition software that google doesn't? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4olrp0/eli5_what_is_the_point_of_imagebased_captchas_if/ | {
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"Captchas don't need to be perfect to be useful. If robots are making 5 accounts an hour then it's not really the end of the world, if they are making 5 accounts a second then a service quickly can get overwelmed. A speed bump can be as useful as a stop sign. ",
"Ticket sellers hire people to solve Captchas. They have software that automate purchasing, but require humans to handle the data input.\n\nI did this for a living years ago. (So sorry.)"
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aeoob9 | how does comparable gpu's have completely different power needs? | I don't know if it's the right subreddit, but I wanna ask: how does nvidia geforce gt 1030 need 30W, and gtx 560 needs 150W, while they have basically the same performance? (In benchmarks gt1030 has 140th place, while gtx560 has 141th) | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/aeoob9/eli5_how_does_comparable_gpus_have_completely/ | {
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"More modern manufacturing process, using smaller transistors that leak less heat during operation, and improvements to the arrangement of those transistors that results in a more efficient architecture.",
"The amount of transistors determines how well the GPU will perform (it is bit more complicated but good for enough for ELI5).\nAs the technology gets better manufacturers are able to made smaller transistors.\nThe transistor use the same voltage but as they are smaller they use less current. \nCurrent*Voltage=Power\nIf you use the same amount of transistors that are smaller you need less current so less power is consumed, but the performance will be the same.\nYou can also use more smaller transistors to keep the power consumption the same and gain proportionally better performance.\n\n"
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78bfiz | if uranium has a half life of 4.5 billion years, why do uranium fuel rods used in nuclear reactors need to be replaced every six years? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/78bfiz/eli5_if_uranium_has_a_half_life_of_45_billion/ | {
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"Because they are being spent. You can keep gasoline in a barrel for a really long time too, but need to refill your car at pretty regular intervals during use.\n\nThe same concept applies to all fuel, Uranium is broken down in the nuclear reaction, leaving less of it than there was before, at a rate much greater than its natural half-life.",
"Because half life is from natural decay, not fission. Inside a nuclear reactor, we're actively causing the fuel atoms to split at a much higher rate than decay would happen in nature.\n\nPlus there's also a significant difference between natural decay and atomic fission.",
"Uranium-238 has a half-life of ~4.5 billion years. However, Uranium-238 is not what drives a nuclear fuel cycle. Uranium-235, which has a half-life of about 700 million years, along with some other isotopes are the primary fuels in most nuclear reactors.\n\nSome nuclear reactors are designed to operate on refined Uranium with its natural isotope balance, while others require the fuel to be enriched by increasing the proportion of Uranium-235 in the fuel. Yet more reactors permit new fuel to be mixed together with old fuel, burning it again.\n\nWhat makes U-235 so different from U-238 is that U-235 is a fissile material whereas U-238 is not a fissile material.\n\nIn the right concentration, and under the right conditions, fissile materials are capable of sustaining a fissile chain reaction.\n\nFissiling is different than simple radioactive decay. Over time, Uranium-235 will naturally undergo alpha decay into Thorium-231 absent any external intervention. However, if a Uranium-235 atom collides with a thermal (slow) neutron, the atom can literally be blown into pieces.\n\nA single Uranium-235 atom may be broken into Barium-141 and Krypton-92 along with three free neutrons. If these neutrons are then slowed down, they can further interact with more Uranium-235 atoms.\n\nOn the other hand, Uranium-238 naturally decays into Thorium-234 over billions of years. However, unlike Uranium-235 Uranium-238 does not fissile with thermal (slow) neutrons. Instead, it captures them and becomes Uranium-239. Uranium-239 Undergoes beta decay into Neptunium-239 which in turn undergoes beta decay into Plutonium-239, a useful isotope in nuclear weapons. However, Plutonium-239 can capture slow neutrons and become Plutonium-240, a temperamental waste product.\n\nJust for the sake of completion, the radioactive particles emitted by alpha decay (two protons, two neutrons, or a helium-4 nucleus) and beta decay (electron) are not sufficient to start or sustain most fissile chain reactions. Spontaneous fission in Uranium isotopes is rare but does occur so care must be taken to keep concentrations of fissile material below a certain threshold.\n\nIn summary, nuclear reactors aren't powered by the natural radioactive decay of their fuel, but rather by a chain reaction caused by neutrons flying around colliding with fissile material causing said fissile material to break into pieces which in turn causes more neutrons to fly around. The rate of this reaction must be carefully controlled."
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ftq1dp | why do racecars have to change tires so often? usually tires are good for much longer than a day. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/ftq1dp/eli5_why_do_racecars_have_to_change_tires_so/ | {
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"The quick and easy answer is race tires are designed for performance not longevity, as soon as racecars start to lose performance in the tire they change them so that they maintain an optimal race pace",
"Race car tires are quite different from the tires on your car and are experiencing a lot more stress\n\nRacing tires are quite soft at temperature compared to a normal tire, the softer tires give more grip than harder ones and more grip means faster laptimes. Even your softest street tire is still going to be on the order of a hard racing tire while many racing series have soft, super soft, and even ultra soft tires.\n\nYour touring tire is going to be a solid compound designed to give you 30-75k miles at sustained speeds of up to 85 mph, and cornering forces of about 0.5 gs max. An F1 tire will be experiencing 2 g acceleration, 5 g braking, and up to 6 g turns at speeds of up to 230 mph which will get them far far hotter than your car tire.\n\nRacing tires have traded tire longevity for grippiness and its up to the teams to balance the time loss of swapping tires in a pitstop against the time gain of running grippier tires",
"1) Racing tires are under pretty extreme stress during the race, stresses that normal tires don't really experience. Thus, it should come as no surprise that they degrade pretty quickly.\n\n2) If your goal is to win the race, you need optimized performance out of the car, which means you need optimal tires. Even if the tires are still perfectly functional, they may have fallen off the performance cliff and thus you're going to be going more slowly around the track than your competitors on newer tires.\n\n3) It actually *is* possible to design tires that will last the entire race. In many series this is objected to out of cost concerns, but in others the tire degradation is actually deliberate because it helps make the race more interesting. This is doubly true in Formula 1, as the only way to *ensure* teams come into the pits is to swap tires, given that mid-race refueling is banned."
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jq96p | jpeg compression | As a programmer, I see things like lossy data compression as sort of a black art. I believe that everything can be explained in simple terms, so if anyone out there can do it, please do! | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/jq96p/eli5_jpeg_compression/ | {
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"Let's take an image that is 1000 by 1000 pixels. Each pixel requires some number of bytes of data to tell you what color it is. Now, that's a significant amount of data, so a compression algorithm tries to reduce the amount of data you need to store that picture.\n\nI'm not sure if this is how JPEG specifically works, but one 'lossy' way to compress an image is to reduce the number of pixels you store. So, you could divide the picture up into clumps of 4 or 9 pixels, take the average color of that clump, and replace the clump with a single pixel of that color. Now you've cut the amount of data you need to store by 1/4th or 1/9th. Of course, you've also lost a lot of valuable information about the picture.\n\nOne way some algorithms compensate for that loss is in how they reconstruct the image when you open it to view or edit. For example, when re-expanding each pixel into the clump of 4 or 9 it came from, they adjust the color of each pixel based on both the clump's color and the colors of adjoining clumps. This works because images rarely have perfectly sharp lines between color spaces. Instead, colors tend to have gradients or blur together.",
"Well, there are some general ways of compressing data. For instance, there's the obvious \"run-length encoding\" (RLE), which does something like\n\n AAAAAAAAAAAAAAAAAAAAAAAAAAAAAA\n becomes\n A * 30\n\nThis is actually a pretty common pattern. Imagine you've just drawn a picture in mspaint, \"A\" here represents a pixel, and most of the next-door pixels are the same colour. In fact, BMP supports RLE compression.\n\nThe next step up is something like \"Huffman coding\". That's when you take a sentence - say, this entire post - and notice that E is the most common letter. Therefore, it makes sense to spend less bits on it. So if you would ordinarily use eight bits for every character in a post, you could spend say one bit on the E's, and maybe more than eight bits on the uncommon letters, giving you a net filesize reduction in average. Of course, then you have to store your own little lookup table, but generally this is a useful technique, especially if you look at larger blocks than single letters.\n\nSo RLE and Huffman coding are both lossless transforms. There are also more advanced arithmetic and dictionary coding methods, but the point is these approaches are general to basically any type of data. \n\nThe magic thing about JPEG is that you know something more about it than \"oh, it's just a set of bits\". JPEG (and audio, and video formats) represent a signal. A waveform, if you like. Tell you what: by some clever calculus known as the Fourier series, you can approximate any waveform in a finite number of steps. So, you can represent your waveform as a sum of sin() and cos() terms. JPEG doesn't specifically use the Fourier series, it instead uses something called a Discrete Cosine Transform (\"DCT\") which is basically the same idea.\n\n[This image](_URL_0_) sums it up pretty well; any eight-by-eight pixel image can be made up of some combination of each one of those blocks. Of course, you have to do this for every colour channel.\n\nOkay, so here's what we do:\n\n Break up our large image into 8x8 blocks\n For each block:\n Use the DCT to represent the block as a multiple of those wavey-looking blocks\n Store the result as a 8x8 matrix of coefficients\n\nNow we do something incredibly silly:\n\n Round everything\n\nYep, that's right, we just did a bunch of calculus and now we're going to throw half the result away to innaccuracies. We do it in a relatively clever way, though, and that is with a \"quantisation matrix\". You see that wikipedia image? The top-left image, the white square, that's pretty important. If that has a certain colour value associated with it, then it's going to permeate the whole block, and it's going to give a significant effect to the image as a whole. But as you get further along, maybe the other blocks arn't quite as important to the image.\n\nHave a look at [this](_URL_1_), now. This shows a DCT coefficient matrix, being rounded carefully with a fixed weighting matrix, such that we only lose the fiddly detailey bits, retain the important structural aspects of the image, and most importantly, it turns out that (because of integer operations) most of the resulting matrix is full of zeroes.\n\nSo anyway, now we have our entire image represented as... mostly zeroes! We can then apply the earlier mentioned lossless run-length encoding and other types of arithmetic coding like this, in order to really save a whole lot of space. And that's really all there is to it.\n\nCouple other things to note:\n\n* You can choose a level of rounding, or a level of quantisation - hence why if you save a JPEG in Fireworks or Photoshop or The GIMP it'll give you a quality slider from 1 to 100.\n* Basically every digital video format, from VCDs through H.264 also employs a DCT system. There have been a few attempts to replace it with the \"next-gen\" Wavelet approach, but they have immense drawbacks.\n* JPEG generally represents colours as YUV instead of RGB. That's not a big deal, there's just a formula for it. YUV represents brightness vs two colour channels; JPEG usually also drops every other colour pixel, since the eye is more sensitive to brightness detail than colour detail.\n* WebP and H.264 keyframes are both kinda similar to JPEG, but they can use variable block sizes and motion compensation, amongst other cool things.\n",
"Let's take an image that is 1000 by 1000 pixels. Each pixel requires some number of bytes of data to tell you what color it is. Now, that's a significant amount of data, so a compression algorithm tries to reduce the amount of data you need to store that picture.\n\nI'm not sure if this is how JPEG specifically works, but one 'lossy' way to compress an image is to reduce the number of pixels you store. So, you could divide the picture up into clumps of 4 or 9 pixels, take the average color of that clump, and replace the clump with a single pixel of that color. Now you've cut the amount of data you need to store by 1/4th or 1/9th. Of course, you've also lost a lot of valuable information about the picture.\n\nOne way some algorithms compensate for that loss is in how they reconstruct the image when you open it to view or edit. For example, when re-expanding each pixel into the clump of 4 or 9 it came from, they adjust the color of each pixel based on both the clump's color and the colors of adjoining clumps. This works because images rarely have perfectly sharp lines between color spaces. Instead, colors tend to have gradients or blur together.",
"Well, there are some general ways of compressing data. For instance, there's the obvious \"run-length encoding\" (RLE), which does something like\n\n AAAAAAAAAAAAAAAAAAAAAAAAAAAAAA\n becomes\n A * 30\n\nThis is actually a pretty common pattern. Imagine you've just drawn a picture in mspaint, \"A\" here represents a pixel, and most of the next-door pixels are the same colour. In fact, BMP supports RLE compression.\n\nThe next step up is something like \"Huffman coding\". That's when you take a sentence - say, this entire post - and notice that E is the most common letter. Therefore, it makes sense to spend less bits on it. So if you would ordinarily use eight bits for every character in a post, you could spend say one bit on the E's, and maybe more than eight bits on the uncommon letters, giving you a net filesize reduction in average. Of course, then you have to store your own little lookup table, but generally this is a useful technique, especially if you look at larger blocks than single letters.\n\nSo RLE and Huffman coding are both lossless transforms. There are also more advanced arithmetic and dictionary coding methods, but the point is these approaches are general to basically any type of data. \n\nThe magic thing about JPEG is that you know something more about it than \"oh, it's just a set of bits\". JPEG (and audio, and video formats) represent a signal. A waveform, if you like. Tell you what: by some clever calculus known as the Fourier series, you can approximate any waveform in a finite number of steps. So, you can represent your waveform as a sum of sin() and cos() terms. JPEG doesn't specifically use the Fourier series, it instead uses something called a Discrete Cosine Transform (\"DCT\") which is basically the same idea.\n\n[This image](_URL_0_) sums it up pretty well; any eight-by-eight pixel image can be made up of some combination of each one of those blocks. Of course, you have to do this for every colour channel.\n\nOkay, so here's what we do:\n\n Break up our large image into 8x8 blocks\n For each block:\n Use the DCT to represent the block as a multiple of those wavey-looking blocks\n Store the result as a 8x8 matrix of coefficients\n\nNow we do something incredibly silly:\n\n Round everything\n\nYep, that's right, we just did a bunch of calculus and now we're going to throw half the result away to innaccuracies. We do it in a relatively clever way, though, and that is with a \"quantisation matrix\". You see that wikipedia image? The top-left image, the white square, that's pretty important. If that has a certain colour value associated with it, then it's going to permeate the whole block, and it's going to give a significant effect to the image as a whole. But as you get further along, maybe the other blocks arn't quite as important to the image.\n\nHave a look at [this](_URL_1_), now. This shows a DCT coefficient matrix, being rounded carefully with a fixed weighting matrix, such that we only lose the fiddly detailey bits, retain the important structural aspects of the image, and most importantly, it turns out that (because of integer operations) most of the resulting matrix is full of zeroes.\n\nSo anyway, now we have our entire image represented as... mostly zeroes! We can then apply the earlier mentioned lossless run-length encoding and other types of arithmetic coding like this, in order to really save a whole lot of space. And that's really all there is to it.\n\nCouple other things to note:\n\n* You can choose a level of rounding, or a level of quantisation - hence why if you save a JPEG in Fireworks or Photoshop or The GIMP it'll give you a quality slider from 1 to 100.\n* Basically every digital video format, from VCDs through H.264 also employs a DCT system. There have been a few attempts to replace it with the \"next-gen\" Wavelet approach, but they have immense drawbacks.\n* JPEG generally represents colours as YUV instead of RGB. That's not a big deal, there's just a formula for it. YUV represents brightness vs two colour channels; JPEG usually also drops every other colour pixel, since the eye is more sensitive to brightness detail than colour detail.\n* WebP and H.264 keyframes are both kinda similar to JPEG, but they can use variable block sizes and motion compensation, amongst other cool things.\n"
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5ickcc | why do people lose weight during sleep? | Basically the title. About 3 months ago I started to log my eating habits as well as weight loss/gain. Measuring at night, I noticed that in the mornings sometimes I could go down as much as 2 pounds. Anyone care to explain? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5ickcc/eli5_why_do_people_lose_weight_during_sleep/ | {
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"water loss, either through sweat, pee, or just the humidity in your breath.\n\nthe other is carbon dioxide, inhale oxygen, exhale CO2. Add up all those carbons and you can get a measurable amount of weight.\n\nBut of your 2lbs, i would be sure atleast 75% of it was water.",
"You're still breathing, heart's still pumping, brain's still thinking right? All of that requires energy from food in your belly or fat reserves. \n\nThe mass lost leaves mostly through sweat, CO2 when you exhale, and that one time you pooped the bed. ",
"Two main things.\n\nOne is just that you exhale and sweat a fair amount of water all the time - at night, you aren't replacing that at all, so you lose some water weight. (Typically why a lot of people are thirsty first thing in the morning.)\n\nBut also because you are constantly exhaling weight - this is actually the main mechanism that you lose weight period.\n\nYou inhale oxygen (o2), and breath out carbon dioxide (CO2) and water. Your body took the oxygen and reacted it with sugars in your body (made from carbon, oxygen, and hydrogen), which result in the gases you exhale. When you lose weight, it's because of the carbon and hydrogen you are adding to your exhaled breaths.\n\nRelated fact - most of the mass of plants comes not from their roots but from the air - they take in CO2 and release O2, keeping the Carbon to build their tissues.",
"You body is taking in oxygen, and breathing out oxygen plus hydrogen (water) and oxygen + carbon (carbon dioxide). \n\nThat is basically how *all* long term weight is lost, and over the course of 8 hours, it adds up. Also, you perspire while you sleep, and that contributes too.\n\nIn addition, bathroom scales are not terribly accurate, and differences in temperature and humidity between evening and morning can skew their results."
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7v3lj7 | the difference between men's and women's deodorant, aside from price | My friend notes that guys stick deodorant is cheaper, and obviously there's a lot that's just marketing spin to sell products, but is there any/much relevant chemical difference between them, and if so, what is it; and thirdly, does that drive the price difference at all? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/7v3lj7/eli5_the_difference_between_mens_and_womens/ | {
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"The ingredients. \n\nWomens products tend to contain more fragrances and moisterizers then men's products.\n\nThose extra ingredients don't come free.",
" > and thirdly, does that drive the price difference at all\n\nNo. The price difference is almost entirely due to marketing. The main differences between mens and womens is the scent and the packaging. It's the packaging you're paying more for in womens deodorant. "
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300gbo | why don't word processors like ms word have extensive autocorrect like smartphone keyboards do? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/300gbo/eli5_why_dont_word_processors_like_ms_word_have/ | {
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"Extensive autocorrect on smartphones exists because typing on them is hard for most people. When you have a full keyboard, and in a word processor for desktop you are expected to, it's more annoying than helpful for the program to make guesses about what you *meant*."
]
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4zm67t | how do venus flytraps digest? | My only guess is they break food down with some secretion, but I really haven't a clue. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4zm67t/eli5_how_do_venus_flytraps_digest/ | {
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"They secrete digestive enzymes. Interestingly enough, the digestive action of venus fly traps seem to have come from defenses against insects that were co-opted into carnivory. Jasmonic acid, which is used in other plants to activate defense mechanisms, is used by the venus fly trap to activate digestion."
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kj41n | how does a new show get on tv? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/kj41n/eli5_how_does_a_new_show_get_on_tv/ | {
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"Someone comes up with an idea and pitches it to a network. \n\nIf the network likes the idea they create a \"pilot episode\" so they can see if they still like it and show it to other people to see if they like it too.\n\nIf that goes well then the show is made and broadcast on TV.",
"Someone comes up with an idea and pitches it to a network. \n\nIf the network likes the idea they create a \"pilot episode\" so they can see if they still like it and show it to other people to see if they like it too.\n\nIf that goes well then the show is made and broadcast on TV."
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3iwrhk | ...why does flash seem to be universally hated? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/3iwrhk/eli5why_does_flash_seem_to_be_universally_hated/ | {
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"A lot of people are just jumping in on the bandwagon because they see that you're supposed to hate it so they hate it. But they have no idea why.\n\nIn practice, it's a big security vulnerability in the browser. That's the main thing. There's also performance and the fact that its inherently tied to Adobe. If you want more information, googling \"why is flash bad\" will give you more information. I don't understand why you need to make an eli5 thread for this. ",
"It takes forever to load, \nsometimes you need to install shit to make it work at all, \nit takes control of your keyboard unless you click outside the flash box, \nyou can't search in it, I can't see it with my iPhone, \nit belongs to a big corporation that forced it down our throats.... \n\nShall I continue?",
"Flash isn't universally hated but there is a movement to eliminate it. A lot of the keenest supporters of this movement are people who design web browsers (like Firefox and Chrome). They hate Flash because running multiple Flash applications (like when you have several tabs open at once and they all have little animated video ads on the side) can overwhelm their browsers and make them crash. These events can also cause a huge memory leak and soak up a lot of CPU power, to the point other programs start shutting down on your computer. ",
"Flash is a program that lets you do many complex things in a web browser, without having to install separate programs for those things on your computer.\n\nIt sometimes does these things in an inefficient, insecure, and imperfect way.\n\nThat's not ideal, but the biggest part of why it's disliked is that it's used for relatively simple purposes that should not need it. When Flash is running for an \"obvious\" reason, you do not know what else it is doing. It could be doing something outrageous to try to steal your data, or it could just be displaying a video. It has the capacity to do so much that invoking such a powerful program for every little thing on the internet ends up being a huge security risk. Google is moving towards blocking ads that invoke Flash, and ads are actually a great example of flash run amok. It pops up out of nowhere and you don't always have the ability to prevent it from loading and wasting your bandwidth; you also can't always stop it from wasting your processing power and making noise even if you don't want that item to play. ",
"Have you seen that goofy outfit he wears? We get it dude, you like red and yellow.",
"It's not universally hated. It's just outdated. In the internet of 10 years ago, flash was the coolest thing ever. Newgrounds was the shit, man."
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1mrbkh | what does the recent increase in arctic ice say about global warming and climate change? | An article on the front page today mentioned this, and I'm mostly oblivious to meteorology.
Article: _URL_0_ | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1mrbkh/eli5_what_does_the_recent_increase_in_arctic_ice/ | {
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"One year does not a trend make on a long term global temperature graph. \n\nTherefore, this really says nothing at the moment. Come see me in a couple or 10 years.",
"Here is a sequence...\n\n88, 86, 84, 82, 80, 72, 76\n\nWhat does that tell you?\n\nLooking at the trend, you would say there is a clear and pretty obvious decrease of 2 per data point. But there is in an unexpectedly steeper drop at the penultimate data point. There is no explanation for it either.\n\nBut that if you ignore that value, the trend is still linear.\n\nThe Arctic ice is like that. We're seeing a steady decrease over time. Last years was unexpectedly worse (and out of sequence) but just because this years is back in sequence (and not as bad as last years) doesn't mean the trend is being reversed, or that the trend never existed."
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"http://arstechnica.com/science/2013/09/arctic-melt-season-over-leaving-behind-more-ice-than-recent-years/"
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6kxkoi | when we first started measuring temperature how did we decide how large a degree would be? was it merely and arbitrary figure that worked, or was there a specific reason behind it? | I was laying by the pool today alone, immersed in my own thoughts and began to wonder about measuring temperature. I understand that time is divided into days because it is an observable phenomenon that occurs regularly, but what about temperature? Is there any history behind the decision to measure degrees at precisely the size we do, or is it just arbitrary? Is there any logical reason why we didn't decide that a degree should actually be measured larger or smaller or than it is? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/6kxkoi/eli5_when_we_first_started_measuring_temperature/ | {
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"It's based on water. They froze some water and decided that would be 0, they boiled some and decided that would be 100. So it's arbitrary in the sense that 100 is an arbitrary number but that's what it's based on.\n\nThe temperature of boiling water will always be the same whether they decided to say it would be called 100 degrees or something random like 41 degrees.",
"I assume you mean the Farenheit scale. \n\nFahrenheit's scale was based on the work of Ole Rømer. \n\nIn Rømer's scale, brine freezes at zero, water freezes and melts at 7.5 degrees, body temperature is 22.5, and water boils at 60 degrees. \n\nFahrenheit multiplied each value by four in order to eliminate fractions and increase the granularity. \n\nHe then calibrated his scale using the melting point of ice and normal human body temperature and adjusted the scale so that the melting point of ice would be 32 degrees and body temperature 96 degrees, so that 64 intervals would separate the two.\n\nThis allowed him to mark degree lines on his instruments by simply bisecting the interval six times.",
"There are different scales. Perhaps the easiest to see how we got it is Celsius.\n\nWe took the point where water freezes and the one where it boils and decided that one would be 0° and the other 100° and making each degree 1/100 of the difference between boiling ad freezing water.\n\nOther scales uses similar reasoning."
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804ppu | why hasn’t cancer been bred out of the gene pool by natural selection? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/804ppu/eli5_why_hasnt_cancer_been_bred_out_of_the_gene/ | {
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"Because cancer isn't solely genetical in origin. There are various causes, including viruses. Also, some cancers don't normally appear until middle age or after, so victims would have already had children.",
"Because cancer isn't an inherited disease. Cancer isn't even one single disease. You can inherit genes that predispose you to types of cancers, but cancer is just random mutations in cells that make them grow out of control. They can happen in in any person at any time; sometimes in response to carcinogens or mutagens, and sometimes just randomly for no reason at all. ",
"In addition to what the other people have said, most types cancer don’t show up until you are in your 60s or older, long past childbearing age. If you’ve already reproduced, there’s not a whole lot of selective pressure being applied towards any negative traits that appear after you’ve had your kids, and getting cancer at 60 isn’t likely to stop your kids from having their own kids at 25",
"if you wanted cancer to be bred out of a gene pool, you would need to have extremely elderly people continuing to give birth. species that appear to have reduced risks of forming cancers tend to be very long lived creatures, such as elephants and whales, which presumably also feature extended reproductive phases. this means individuals who died of cancer had fewer babies and thus had a smaller impact on the gene pool.\n\nthis is because the risk of cancer increases with time, meaning animals who finish reproducing in fewer years have a reduced risk of ever forming cancer in the first place before it no longer had any effect on the gene pool. so for example, lions and tigers don't usually live long enough for most cancers to be an issue, and their reproductive cycle matches that expectation, with large litters starting young. if one had an extended life (gene pool wise this is like domestic cats) they run risks of developing all sorts of health problems, including cancer. \n\n\nif a creature is likely to get cancer in its old age, but reproduced a lot when it was young, the gene pool will continue to feature genes that result in cancers. if however, old age still is viable reproductively, you would expect to see any individuals who *dont* get cancer influence the gene pool, resulting in a shift of increasing likelihood of an individual having a reduction in cancer rates. this only becomes true however once an animals reproductive phase is long enough in actual years for cancer to be a reasonable concern.\n\n"
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3j1be9 | the price of eggs have skyrocketed, but why hasn't the price of chicken gone up? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/3j1be9/eli5_the_price_of_eggs_have_skyrocketed_but_why/ | {
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"The chickens we eat are not the same chickens that lay the eggs we eat. Apples and oranges.",
"Because the chickens that lay eggs were severely impacted by the avian flu, killing more than 45 Mil birds while the chickens that are grown for eating were almost completely flu free. Turkeys were affected as well and the price for turkeys this fall are expected to be very high with shortages nationwide."
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14lc1t | what exactly happens when a music producer "masters" a song/album? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/14lc1t/eli5_what_exactly_happens_when_a_music_producer/ | {
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"When most people hear the term 'mastering', they are think of the mixing process, aka balancing volumes and adding effects, etc. Mastering is actually a specialized subset of mixing that is a form of audio quality control or quality assurance. Only a relative handful of people and studios are capable of mastering, compared to the thousands of mix studios out there. The goal of mastering is to get every track sounding as good as possible across multiple systems, meaning that the end product should sound great through your car, stereo, headphones and laptop speakers. Along with this, many artists' songs are recorded and mixed in multiple locations, and it's the mastering engineer's job to get them to sound like they all are polished to the same standard. Lastly, mastering produces the final CD or vinyl format for distribution and archives the tracks (often separated into clean lyrics versions, a capellas and instrumentals) for the publishing company. ",
"Mastering adds that final layer of polish to the track before it's sent for pressing and/or distribution. The engineer mastering the audio may also take in to account where the track will be played, so in the case of a pop single she'll make sure it will sound good when broadcast over FM radio.\n\nWhen a track is ready for mastering typically nothing is changed structurally. The focus is on how it sounds. The engineer will not add elements to the track, such as instruments, verses, choruses, they will not necessarily boost or lower the levels of particular instruments, and will not necessarily decide on fade-ins and fade-outs.\n\nThe engineer may want to make the track sound broader, brighter, or heavier, for example. To do this they use a bunch of tools, such as compressors and equalisers. We'll take a quick look at those two.\n\nA compressor can be used in lots of different ways but for mastering one technique is levelling out some of the dynamics of the track, this means the loud bits won't be too loud compared to the quiet bits. This could be useful for radio play, for example. (I have just vastly simplified and skipped over compression but this could be a whole ELI5)\n\nAn equaliser lets you target and boost, diminish, or even cut frequencies. High frequency sounds are things that have a sharp, cold, tingle to them (this is subjective but I'm trying my best), so the drummer's hi-hats are a great example. Low frequency sounds are things that are deep, warm, and have bass, so the drummer's kick would be a good example.\n\nRemember how I mentioned that the engineer might want to make the track a little brighter? She could use an equaliser to boost some of the higher frequencies in the track. If she'd like a little more bass, she could boost the lows. She's basically turning the volume up or down on very specific frequencies of the track, rather than the whole track.\n\nOur analogy could perhaps be that mastering is like adding salt, or pepper, to a dish once it has been prepared. You can vastly change the flavour but you cannot add or remove any ingredients. You could sprinkle salt on a particular area of the dish though. Ideally by adding salt and pepper you are enhancing the flavour of the entire dish.\n\nSource: I make music, signed to a record label, have been trained in engineering, just sent my latest track to be mastered two days ago.",
"Mastering has two parts. Firstly is taking the individual stereo tracks for an album and making them sound consistent with each other and with other music of the same genre. The simplest thing here is to make sure the tracks are the the correct level. You don't want a quiet ballad to be louder than your heavy metal track. There are other things to make consistent as well, like making sure one track has about the same amount of bass as the other tracks.\n\nThe second part is the technical stuff of making a the master recording that will get duplicated. This includes things like setting the correct gaps between tracks on a CD (and maybe making hidden tracks), or making sure there is not two much bass for a vinyl record (that could make the needle pop out of the groove).\n\n",
"Whee! This is an interesting topic indeed.\n\nMastering is the 'black box' of the audio world. The tracks are recorded, processed, mixed, and then sent to the mastering engineer.. and then when they come back.. they're just better. And completely ready for release. Nobody knows how. (There was a rumor that mastering engineers are trained in yoga and the Dark Arts).\n\nKidding apart, ideally mastering fulfills these goals:\n\n* Songs across an album/release are processed to sound similar in loudness and frequency;\n* Raw edges are polished,(noise and other strange stuff is removed) and the song is given that professional 'sheen' using good quality tools and a good system and room. This includes making sure the whole work sounds somewhat uniform in volume(even within a song), and emphasizing the right pitches to make it sound good with EQ.\n* The audio is also worked on to ensure that it sounds the same through as many music systems as possible. It'll be bad if your beautiful orchestral piece is too soft to appreciate on your daughter's iPhone 'buds right? And your vocalist will hate it if his vocals are inaudible for some weird reason(phase alignment?) when played in the nightclub. The mastering engineer sees to it that you don't get no unwanted surprises.\n* Special versions(a capella etc) are worked out\n\n* The audio is then converted to a format suitable to send to the CD factory guys or iTunes(or wherever), with the necessary information too: \ntrack name(s) embedded, artwork added etc.\n\nThat's it folks! \n\nWell, there's another thing I'd like to add: too many people think that mastering simply means making a song louder. That is absurd. Your music system has a big fat shiny volume knob for that. The mastering engineer WILL smoothen out sudden volume changes and overly soft parts, and maybe push up the softest parts sometimes. But that's all part of the mastering and volume is not really the ME's primary goal. ",
"There are a lot of solid but complex answers. Here is a simple eli5\n\nMixing is how it sounds. Take all your available sounds that you want to use and mix them together. This process is where all the instruments and vocals are balanced. This is where they do a lot of finer tweaking, like adding effects to individual instruments and vocals.\n\nMastering is where they make each track sound like one cohesive professional album.\n\nHave you ever heard a song where you thought \"those drums are louder than the vocals\"? That is a mixing issue.\nHave you ever had a mixed cd where each of the songs were at a different volume? That is a mastering issue.\n\nFor more in depth analysis, read the other high quality responses. ",
"This will explain the LIMITING aspect of Mastering (How they make things louder), it also clears up the difference between this compression and limiting people are talking about. \n\nHey little Jimmy! \n\nOk, compression and limiting are two different things buddy. They are done using the same tool but there is a difference! \n\nCompression - is like the limbo. Someone holds a pole 3m away from you at a certain height (Compressor Threshold), when you get close to the pole, you are taller than it, as you get closer to it, you start to duck lower. The speed at which you do this is called the 'attack', (a common setting of compressors). After you have gone under the pole you start to stand up again, the speed at which you do this is called the 'release', (another common setting of a compressor.)\n\nSo the compressor reduces tall people (loud sounds) in height (volume) by a certain amount (threshold) for a period of time controlled by your approach and stand up speed. (attack and release) This motion is rhythmic and flowing and makes drums sounds explosive and controls vocals among other uses.\n\nLimiter - This is a compressor which has a threshold (pole height) set at hip level over 10m (or a 4 minute song). Except your not using a pole, you're limbo-ing through a low tunnel. Your body length (dynamic range) is now smaller and closer/squished together as you go through the tunnel for a longer period of time than when it was just a quick duck under a pole.\n\nHow it makes things louder - During your 10m limbo through the tunnel, your body is now only 1m high. Imagine that the roof of the cave holding the tunnel your in, is 2 meters high (0dB). I can make your body seem really big overall (loudness), by making the tunnel you're in, as big as the cave! (turning up the volume to reach 0dB) Now your legs/head/shoulders etc are all double as big. \n\nUnfortunately, this now means your body is, out of proportion, unnatural and not as pleasant to listen to. However, every kid on the block is reeeeeaaaally big so you gotta compete with them, even though you're all just out of proportion kids that were fine to begin with! (Loudness War)\n",
"As its already been explained, if anyone is interested i can post a premaster/postmaster of a track of mine to show you the difference?",
"Meator's explanation covers a lot of it but that's not all.\n\nHe/she is correct in saying that most people confuse mastering with mixing.\n\nFor people who don't know: when music is recorded, many different things are often recorded at the same time. Drums are usually recorded with a minimum of six microphones (though there are exceptions). All of these different microphones are recorded at the same time and are saved to separate files so that they can be balanced during mixing. This is true for other instruments as well. A typical rock song might have fifteen or twenty 'tracks' or so.\n\nWhen you finally get all of those separate tracks sounding like you want them to, you mix them down to a single file, somewhat like something you could play on your iPod.\n\nThen we get to mastering. The mastering engineer basically polishes the whole thing up and makes sure the average track volumes are the same, along with the other edits mentioned by Meateor.\n\nVinyl is a whole different deal and it has to be mastered separately (you sometimes hear people refer to a 'vinyl master'). To understand why this is the case, you need to think of how a turntable works: a needle runs through a groove and one side of the needle picks up the sound headed for the left speaker and the other picks up the sound for the right speaker. This sound is represented on the record by tiny little ridges. Bass frequencies make larger ridges than high frequencies. So when doing the vinyl master they make sure that all of the sound that is lower (below a certain frequency) is mono (that is, it is equally loud in both speakers). Otherwise, when the listener plays the record, it could actually cause the needle to jump out of the groove resulting in a party fail.\n\nAnyway. Hope that was helpful.\n\nEDIT: TL;DR: It makes things sound a little shinier and it's a tad different for vinyl.",
"Audio guy here. I'll try to explain it really simple. Music producers don't master the album. \"Mastering Engineers\" do it.\n\nProducers oversee the entire album. I mean they used to. Now everybody \"does\" everything, so they call themselves producers. The producers' job is to make sure the album is the best that the artist or band they're working with can deliver. \nThe producer, depending on his/her skills can call the shots even on the song forms, the riffs, melodies or just sit back and wait around until the band finally comes up with something that sounds *usable*...\n\n\"Nowadays producers\" are people who can find their way around ableton live, or logic pro or whatever digital audio workstation you may need, and some kind of keyboard skills so that they can play their ideas in the studio and make a beat. Then hope for a singer to come up with a nice vocal line or whatever.\n\na mastering engineer does the final touches to the tracks in the album so you don't need to turn them up, or make additional EQ in your car or in your i tunes, or whatever.\n\nTo hear the difference on the mastering fashion, compare a Tim Buckley song to a Jeff Buckley song. Try to hear the difference on the sound levels.\nThen play a Katy Perry song. It'll be even louder. This is some other debate called the \"loudness wars\" if you're still interested google that and read the wikipedia article. "
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eba5kp | what makes ab+ plasma and platelets a universal donor? | I’ve been donating blood regularly for years, and donating plasma and platelets more regularly recently. I understand some basics around blood interoperability, but don’t know what makes AB+ a universal platelet donor. Can someone fill me in? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/eba5kp/eli5_what_makes_ab_plasma_and_platelets_a/ | {
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"It get a bit more complicated, but to break it down into just the AB things, because that's what explains this mostly. You have two main blood cell factors, A and B. They interact a bit like puzzle pieces with some clotting factors, such as in a platelet donations. Some of these factors cause any blood cells with an A to clot up and some with a B to clot up and your blood does not have whichever makes your blood clot up. Because an AB donor has both A and B on his or her own blood cells, that person does not have clotting factors that interact with either of them. As a result, your platlet donations aren't going to cause any issue with anyone because you lack either of the two main factors in you platelet donations. \n\n\nNote that the opposite is true with regular blood donations. AB is a universal recepient for the same reason but can't donate to anyone other than another AB.",
"AB+ is a good platelet donor because their platelets dont contain any antibodies towards the other blood types. They have the A, B and + on their red blood cells so they dont see any of those as foreign if a donated cell has one of those on it"
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30fe29 | what is an actual good strategy for taking those personality tests you find on job applications? what exactly are they looking for? | I work for a franchise retail store. A major one with locations everywhere. My franchisee just bought a new store last week and promoted me to GM. But before I could go through corporate training, I had to take a computer based "apptitude" test.
The test is basic reading, basic math, and then a personality test. The same kind I've taken a bunch of times on job applications. It's a list of statements that you either "agree" or "disagree" with. Some of them are job specific like "I think it's ok to take merchandise as long as it's only $5". Some of them are vague like "I worry about things to the point I can't sleep."
The problem I have is I overthink the shit out of these questions, especially the vague "life-philosophy" type ones. Just to take an example:
"Everything is possible."
Would you agree or disagree with that? I mean, technically it's not true, right? It's not possible for me to count all the integers out loud before i die. But saying that anything is possible reveals a positive attitude and might be the kind of person you'd want to hire. But, then again, I don't want the test to think I'm just telling it what it wants to hear, you know? What if I get flagged for being a "yes-man"?
And the one I mentioned earlier: "I worry about things sometimes to the point I can't sleep." Saying you do that is kind of neurotic, but it also could be good to worry about your job. It shows you care. I could just see both answers being good or bad depending on the reasoning.
So can anyone tell me what the test makers actually want? What would be considered a "good" answer? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/30fe29/eli5_what_is_an_actual_good_strategy_for_taking/ | {
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"the more elaborate ones have a combination of questions that let them see if you're honest. \n\nNot being able to sleep because of stress cannot be good in my view. Bad stress management. \nIt's like saying yes to the question \"do you have psychological problems?\". \n\nThe everything is possible one is trickier indeed, it depends on how shallow the test is. I guess that when in doubt, I'd just answer honestly. \n",
"Just tell the truth. The only time I've had to take such a test was when I worked at a movie theatre to sell tickets and popcorn (which I find somewhat ironic, as I've since held far more important jobs that didn't, including one that required national security clearance), and one problem with the test was that it weeded out answers it thought were fake. So if you answered in a manner that made you seem like Honest Abe reborn, it would fail you. \n\nSo I agree with Formagella, just answer honestly with respect to your own beliefs. "
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4akpiz | how does a program that is a 2mb download take up 30mb of space when installed? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4akpiz/eli5how_does_a_program_that_is_a_2mb_download/ | {
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"It depends. There's really 3 scenarios:\n\n1. It's a compressed installer that extracts itself as part of the installation\n\n2. The installed runs a bunch of scripts that generate placeholder files\n\n3. It's a stub installer that actually is just downloading additional files as part of the installer (See: [Java](_URL_0_) Online installer (stub) - 718kb vs Offline (full program install) - 47.94mb\n\nEdit: Option 1 was extremely common back in the day, but option 3 is very prevalent nowadays, and is used for most update packages, mostly because it's implied in today's world that your computer is going to be always online, so they can use an online installer (stub) in order to always deliver new files as opposed to a single installer getting circulated inside a company for years."
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2k7v2e | how are home run distances in baseball calculated as soon as the ball lands? | Even home runs hit out of the stadium seem to be known immediately. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2k7v2e/eli5_how_are_home_run_distances_in_baseball/ | {
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3fzn7e | why the american constitution is still the same yet laws change | As in, why has nobody decided that it may be a little out of date and thought to change it?
Bonus points for explaining how drawn out the process would be to change it. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/3fzn7e/eli5_why_the_american_constitution_is_still_the/ | {
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"We have amendments for this exact reason. Changing the original document can be dangerous, like in Animal Farm, where all four-legged were equal, then all four-legged were equal both some are better. We want to keep the original writings intact, while adding more to it as the times change.\n\nA lot of the problems with the Constitution is ambiguity. \"All men are created equal.\" Did they really mean all men, or just white men? Do women count? The 13th and 19th Amendments addressed those questions.",
"The Consitution has been changed 27 times (although the first 10 changes happened at the same time). These changes are called \"Amendments.\" The procedure for passing an Amendment is described in the Constitution itself. The way to pass an Amendment is to have it approved by 2/3 of both branches of Congress (the groups of people who are in charge of making laws), followed by having 3/4 of the states approve it as well. As you can see, lots of people need to vote in favor of a proposed Amendment for it to succeed, so you can only pass one if it's really popular. Time needed to approve an Amendment varies, but in some cases it has taken less than a year. "
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1sna0v | why does society have "girl stuff" and "guy stuff" | as an example: my brother has just had a daughter and also has a step son. The daughter is a newborn and the step son is 3. With the season being one for giving, I'm seeing a definite difference in the gifts being given to each of them. The step son is generally given "boy things" which are typically gi joes and toy tools. The daughter is given lots of pink things and baby outfits that say things like "Girl Power". I was shopping with my mom and she picked up a doll that was essentially a child(because who loves taking care of children more than children right?) and said, "oh this will be good for newborn girl in a year or two.
I've noticed that the same thing still applies as an adult. "guy things" are typically guns videogames and outdoorsy stuff. "girl things" tend to be books about romance, clothes, and jewlery.
Why are do these constructs exist? Is it more of a result of nature or nurture? Also, why would a child want to have a doll that is essentially a child to take care of? Especially the ones that pee themselves? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1sna0v/eli5_why_does_society_have_girl_stuff_and_guy/ | {
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"Because boys and girls are different.. Give boys barbie dolls and soon they're stripped naked and they're whacking things with them like hammers... give girls GI Joes and they play dress up and act out tea parties with them. Obviously I know this is a GROSS generalization so don't waste your time flaming me, but there's just inherent differences between the sexes that all the PC open-minded modernism in the world can't beat out of kids. ",
" > Is it more of a result of nature or nurture?\n\nThere is a lot to this subject, but I'm going to focus on this bit.\n\nThis question is generally bogus. Nature and nurture are both important aspects when understanding behavior. In this case, there are clearly biological differences between males and females and these differences are a reasonable explanation for the development of cultural gender differences, but many of the cultural differences are not consistent between cultures or across time (e.g. pink used to be considered too masculine for girls).\n\nWhen we look at infants, we find statistically significant differences between sexes in many ways, but just because they are statistically significant, doesnt mean that all boys are more geo-physically oriented and less emotional-socially oriented than girls. The numbers of sensitive boys and rowdy girls are very high and the degree by which these stereotypes are reinforced as they age varies between cultures.\n\nIn short, gender differences have their basis in biology, but culturally we have taken these biological foundations and amplified them in all sorts of interesting, and sometimes bizarre ways.\n\n > Also, why would a child want to have a doll that is essentially a child to take care of? Especially the ones that pee themselves?\n\nFor the same sorts of reasons that children might want toys which let them pretend to kill things or cook things. The impulse to care for each other is very deep and the ability for children to play to practice their impulses is very important for their development.",
"Most of the associations are society driven. As you can see, from birth, girls and boys are given different things. Marketing reinforces it as do peers who may ridicule those who like the \"wrong\" stuff.\n\nThat being said, I think there is some nature in it. When my daughter was born, we let her play with whatever she wanted, and we did our best not to discourage any particular toy or activity due to her gender. When she received a doll as a gift, it quickly became her favorite toy. She would often feed it, put it to night-night, and change its clothes. I've tried getting her interested in building toys (my favorite as a kid), but she still seems to prefer playing with her doll or stuffed animals most of the time.",
"If it makes you feel better it's almost certainly only the parents who are perceiving the pink to be girly and the blue to be manly and it *should* have no actual impact on the child.\n\nEven in my grandparent's lifetimes pink was the color for boys and blue was reserved for baby girls (Source: 'Parent's Magazine' 1939). Back then blue was associated with purity and the virgin Mary and all that while red was associated with masculinity and thus pink was seen as the younger (paler) version of manly.\n\nThe reason it changed? Hitler.\n\nNow now, before you throw Godwin's Law at me, hear me out...\n\nIn WW2 the Nazi party used pink triangles in the concentration camps to denote gay men. This was widely reported and thus a large number of the GIs coming back after WW2 associated pink for boys with homosexuality because history.\n\nThe more you know."
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83a2jx | sometimes police can enter a house saying they have a warrant, but do not need to produce it for proof to the people in the house? | I've been bingeing LivePD on YouTube, and in this episode the police officer said something I've never heard before:
(starting at about 30 seconds) _URL_0_
The women inside asks for them to produce the warrant, and the officer says that he has one but he is not required to show it?
Is this a state by state thing, or is this the case in most places? I've always heard the police must show you the warrant if you ask for it. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/83a2jx/eli5_sometimes_police_can_enter_a_house_saying/ | {
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"Under the Federal Constitution there is no requirement to show the warrant. There is a standard of reasonableness with regard to the manner of execution of the search or arrest, and some decisions have cited the display of the warrant, but the Supreme Court has affirmatively held it is not a requirement. \n\nSome states do have statutes dictating the manner with which warrants are executed.\n\nKeep in mind, as with all personal rights (i.e. limitations on government power) under the Federal Constitution, states can always expand the proscription (i.e. give you more rights) but they can never limit your rights under the Federal Constitution. \n\nIn short, requiring a warrant to be shown is an additional right, but it is not required everywhere in the U.S.",
"I cannot speak for the law in the USA, but the relevant law in Canada is found at section 29(1) of the Criminal Code of Canada\n\n > 29 (1) It is the duty of every one who executes a process or warrant to have it with him, where it is feasible to do so, and to produce it when requested to do so.\n\nI am aware of only one case in which a search warrant was executed prior to the arrival of the physical copy of the warrant. In that case, the police presence was discovered inadvertently and destruction of evidence became a real possibility. The warrant arrived shortly thereafter and everything was deemed to be kosher.\n\nIn a different case, police officers entered a house prior to a warrant having been issued. The trial judge noted that the information on which the warrant was based was so defective that the police officers hadn't considered what would have happened if the warrant had not been issued. Needless to say, that evidence was excluded.\n\nThere is no requirement that the first person through the door be in possession of a copy of the warrant, but someone has to have it and that person must present it to those that have an interest in the warrant's execution (such as the occupants of a house, or the subject of a DNA order) when requested to do so.\n\nThe scenario that you describe \"I have a warrant but I am not going to show it to you\" would be manifestly unlawful in Canada. The officer would be the subject of a brutal judicial smackdown and any evidence would be excluded from trial."
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30p9u4 | why does my husband get an erection when he's tired? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/30p9u4/eli5_why_does_my_husband_get_an_erection_when_hes/ | {
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"Your body needs to tense a muscle to *prevent* an erection. When you're tired this muscle relaxes and you become erect. Same reason you get morning wood.",
"His body is relaxed and that allows blood to flow to his penis. Normally, the blood flow is limited in that area. ",
"The autonomic nervous system controls lots of physiologic processes in the body without you having to consciously think about them. It has two components: sympathetics and parasympathetics. In general the sympathetic systems can be thought of as your \"fight-or-flight\" response and the parasympathetics can be thought of as your \"rest-and-digest\" or \"feed-and-breed\" response. These two components are in a constant balancing act with each other. When you exercise your sympathetics are more dominant than your parasympathetics. When you're on the couch and relaxing your parasympathetics are dominant. \n\nIn the penis the parasympathetic system controls erections, while the sympathetic system controls ejaculation and detumescence (softening). Your husband is in a parasympathetic state when he is tired and that leads to his erections. ",
"Is it too simple to say because he thinks you're hot? Sometimes I want sexy times with my wife, but my body is too tired for it, well most of my body is too tired. Appreciate it."
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bc78yz | how do people "let go" and choose to die? | I've heard countless stories of people waiting until family members show up to finally let go, or hearing about a spouse dying while you're both sick and one "lets go" after hearing. I just don't understand how anyone can command their body that way. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/bc78yz/eli5_how_do_people_let_go_and_choose_to_die/ | {
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"I'm no expert, but I think a lot of the time that person is actively fighting to stay alive for as long as possible whether it's a conscious or subconscious decision. Once they consciously decide that they no longer want to fight then the brain stops trying to coordinate the body's fight and they then slip away.",
"My mom promised my little sister that she'd wait for her. Even though she'd been in hospice for 3 days, and hadn't been [noticably] conscious for nearly 24 hours, she *knew* when my sister got there and said, \"hey, Mom.\" She died moments later, but she waited. Having watched her die, I can tell you they're sometimes capable of partial consciousness even when they're really close to death. So I believe she heard her voice, and then chose to stop forcing her body to keep going.\n\nWe've got more control over our autonomic nervous system than we realize/exercise. Think about those people who do extreme stunts where they literally *tell* their heartbeat to slow down enough that they can survive an unbelievable amount of time submerged in super cold water. Similarly, if your system is actively shutting down- but you *tell* your heart to keep beating- your body can use its very last reserves to do so. Not indefinitely, of course, but if I can will my heart to slow down when I begin to panic, then a dying woman can will hers to *keep* beating until she hears her daughter's voice.\n\nThat's not a very scientific response. But having witnessed what you're referring to, I think sometimes we have more control over our basic functions than what a healthy person would choose to exercise or explore (or even know how to, in most cases).",
"My friends grandparents just died last week. His grandma died first, and his grandad just stopped eating due to depression. He only lasted a couple days and passed away in his sleep. I guess it's because at their age it takes a lot of work to stay alive, and when you loose the will to keep that up it can end quickly.",
"It's a matter of survival situation. When in danger you release adrenaline to perform better. Here the situation is a psychological state of extreme willingness that activates survival/emergency mechanisms letting you stay alive for longer than if you were peaceful in your mind. After you had what you wanted you have no will to continue releasing those and \"let it go\".\n\nThink of two copies of the exact same person (physically) running a 10 Km race. At 9km both start to get really exhausted :\n- one is letting go and after 30sec can't finish the race cause the body has lost its \"high performing\" state and is now in resting state. It's lost now, even with all the will he can have now, he won't be able to make it.\n- the other one is willing to continue no matter what and so is still releasing adrenaline to his body which allows him to finish the race.\n\nThey were both the same exact person but the different psychological states had different influences on their physical states which led to different outcomes.\nThis is the same phenomenon appearing here.",
"I would add an alternative explanation: the (inopportunely named, in this case...) survivorship bias. \n\nFor every person who died at just the right moment to create a memorable and touching story about how they \"hung on\" until the right time, there are quite possibly 99 other people who died far too early or much later (or not at all!) to make it story-worthy. We only hear about those rare cases where people die at just the right moment, giving something of an illusion that the people may be exerting control over when they die.\n\nNot to say that's not what is happening, in some cases. But it is important to consider such observational biases which are often a simpler explanation for the stories we perceive."
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22o9ce | why are ncaa basketball rules so different from nba rules? | Since there's all this talk about if players are "NBA ready" (the same is said for football players) why are the rules so different? If they groom these players for success, why is there a longer shot clock and shorter games? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/22o9ce/eli5why_are_ncaa_basketball_rules_so_different/ | {
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"The NCAA wants to differentiate itself from the NBA to minimize the perception that the players in one billion dollar league are very well compensated while the players in the other are lucky to get a scholarship.",
"The majority of college athletes don't have anywhere near the same amount of strength, speed and endurance as NBA players. Even the ones who are definitely going to the NBA don't get the same opportunities for training. That's why you see a lot of pro athletes bulk up a ton their first few years in the league. \n\nAlso remember that the vast majority of college athletes will never be close to being on the same level as professionals. Therefore, you need rule differences to reflect the disparity in athleticism."
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3b4c5l | modern germany's outlook and regulations on naziism? | To elaborate, is Nazi paraphernalia *completely* banned in the country? Is there like a common knowledge rule to just *not* bring up the Nazi era? Is Naziism a segment in German history courses?
Please and thank you very much! | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/3b4c5l/eli5_modern_germanys_outlook_and_regulations_on/ | {
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"They do acknowledge naziism in school. Nazi paraphernalia is banned for collecting purposes, although museums can display it. Same goes for Mein Kampf, not allowed to be sold or distributed.\n\nSource: My mother is German, told me about all this.",
"It is actually illegal to publicly display symbols from the Nazi party. [Here](_URL_0_) is a wikipedia article on the relevant law.\n\nIt dates back to the late 1940's and de-nazification. "
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3si1sp | if gas pumps can accurately measure high speed flow, why do they always slow to a crawl at the end? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/3si1sp/eli5if_gas_pumps_can_accurately_measure_high/ | {
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"Think of it like filling a water bottle from a faucet. If you open the tap all the way and try to fill it you will have to stop when the water starts bubbling out of the top from the air trying to escape. The result is that you have a bottle that isn't actually full. Now if you start to close the tap and slow down the flow as the water reaches the top you let the air escape without causing the water to bubble up.\n\nThe same thing happens to the fuel tank in your car. To counteract this the pumps slow down the fill rate when it senses the tank getting full allowing for a full tank without the need to repeatedly restart the pump. "
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9lmohd | we always hear that the military is "fighting to protect our rights." but who are they fighting and why do they want to take away our rights? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/9lmohd/eli5_we_always_hear_that_the_military_is_fighting/ | {
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"That statement is not meant to be taken literally. The implication is that if, *hypothetically,* someone were to bring us harm, the military would stop them.\n\nBy that logic, anyone who joins the military has signed up to (maybe, someday) die for our freedom."
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28acbm | what problems do modern mathematicians attempt to solve? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/28acbm/eli5_what_problems_do_modern_mathematicians/ | {
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"How to make a living as a mathematician?",
"They're working on impossibly hard problems like:\n\n - Is every even number the sum of two primes? \n\n - Start with any natural number x. If it's even, go to x / 2. If it's odd got to 3x + 1. If you do this the cycle 1, 4, 2, 1... repeats forever. Are there any other cycles? \n\n - ~~A Pythagorean triple is three natural numbers so a^2 + b^2 = c^2. Are there any four numbers such that a^2 + b^2 + c^2 = d^2 ?~~ (Oopsies. I did *not* think this one through. Hat tip to /u/Usion and /u/RelentlessPessimist)\n\n - Corrected: A Pythagorean triple is three natural numbers so a^2 + b^2 = c^2. If you make a triangle with lengths a, b and c, it will be a right triangle. Now put two of those together to make a rectangle. Can you make a cuboid (brick shape) from rectangles like these?\n\n - Pick any number N, no matter how big. If you start adding up the fractions 1/1 + 1/2 + 1/3 ... the sum will eventually get bigger than N. This is called divergence.\n\n- When the gaps in a sequence 1, 3, 5, 7 ... are all the same size it's called an \"arithmetic sequence\". For any arithmetic sequence, the sum of reciprocals (1 + 1/3 + 1/5 + 1/7) also diverges.\n\n- Corrected: If the sum of reciprocals of a sequence diverges, it seems that you can always find arithmetic sequences inside (at least three numbers with equal gaps between them). Is this true? If it's true, can you always find longer sequences? How long? (Hat tip to /u/Spetzo and /u/FUZxxl )\n\n- When sequences do not contain an arithmetic sequence (e.g. 1, 3, 9, 27, 81...), the sum of the reciprocals do not seem to diverge. Are there any exceptions to that rule?\n\n - Pi is irrational and e is irrational. Is pi * e rational or irrational?\n\n - What is the [largest sofa](_URL_0_) that can fit around a 90-degree L-shaped corner between two hallways of equal width?\n- We know you can fit one that's 2.2 times bigger than the width squared. And we know that 2.83 times is too big. \n\n\nRecently solved very hard problems include:\n\n - Imagine you are coloring countries on a 2-dimensional map. How many colors do you need to keep the shapes distinct? You usually need three and sometimes you need four. Do you ever need five colors?\n- No.\n\n - Go back to Pythagorean triples (a^2 + b^2 = c^2). Finding triples a + b = c is easy, Pythagorean triples are a little harder but not too hard. Triples that satisfy a^3 + b^3 = c^3 seem impossible to find, but are they? What about other powers (a^n + b^n = c^n)?\n\n- There are no triples (a, b c), if n > 2.\n\nbut the proofs are very long.\n",
"\"Mathematicians\" means a ton of different things, and there's a big difference between academics doing pure research in universities, and people employed by \"the industry\" working on applications. I'll try to provide answers for a few branches of mathematics.\n\nComputer Science: There's a few well-known CS problems (the most obvious ones being P = NP and the [Traveling Salesman](_URL_2_)), and no shortage of stuff for theoretical Computer Scientists to work on. In the industry, Google and the NSA are probably the two biggest employers of computer scientists, with cryptography and AI being some of the most obvious problems they're working on.\n\nGeometry: Modern geometry is nothing like what you studied in school, and is incredibly abstract — one of my best mates wrote a dissertation on \"Equivariant Cohomologies\". Buggered if I know what that means. This is for the most part reserved for pure academics, and, from my experience, \"applied\" geometry/topology tends to mean theoretical physics, for the most part.\n\nNumerical Analysis: AFAIK, fluid dynamics (specifically the [Navier-Stokes equations](_URL_3_)) still provide academics with a ton of interesting stuff to work on. There's also a ton of practical applications for this stuff (a friend of mine did his _URL_0_. on something like detecting structural damage in concrete through the scattering of acoustic waves, and these days he's studying applications to oceanography).\n\nStatistics: Not sure what interesting theoretical problems are keeping academics busy, but in the industry there's a ton of demand for things like building [A/B testing](_URL_1_) models.\n",
"There are also more \"applied\" mathematicians working on equations describing phenomena such as fluid flow, random movement, pattern formation in crystalline structures ...\n\nThe questions one asks are usually of the form: Just starting from such and such property being satisfied, can we show that also this more interesting property will always hold?\n\nIf you want to get an overview have a look at [_URL_0_](http://_URL_0_), where new research papers are made available every day, so that other people can read and comment on them, e.g.:\n\nhttp://_URL_0_/list/math.MP/recent\n\nhttp://_URL_0_/list/math.AP/recent\n\n",
"Are there any math problems that would have rather immediate practical consequences if they were resolved?",
"Math grad student. Am currently trying to solve a variation of the following problem: Show that the [plurigenera](_URL_1_) of a [variety](_URL_0_) are invariant under certain types of [deformations](_URL_2_). Very few work on those type of number identities like stated in the top post (mainly, I would guess, because they tend to be very hard...). You can probably be more productive by exploring newer areas of mathematics than trying to solve age-old identities.",
"The [millennium problems](_URL_0_) are mostly still open. If you successfully solve one of these, you win 1 million dollars. I'm studying Computer Science and the one that is always brought up is P vs NP. Its probably the most important problem in that list, most people suspect that P != NP, but it is yet to be proven. \n \nEdit: Six of these seven problems remain unsolved, to be more exact. The Poincare conjecture was solved by Grigori Perelman who declined the monetary reward.",
"I think there's a lot of misinformation in some of the top-voted answers here. For context, I'm a year or so away from a math phd at a top-five department in the US. Here's what I tell people when they ask me what mathematicians actually do these days:\n\nFor starters, we don't sit around all day trying to solve the famous old problems that some of the other answers in this thread alluded to. At most, we might privately indulge ourselves occasionally in thinking about something big and unsolved, but it would be supremely unproductive to spend even a small fraction of our time attacking some monster problem that has a 100+ year record of going unsolved. As somebody whose field of study is far away from number theory, I would have little more of an idea of where to start in attacking the twin prime conjecture or the Riemann hypothesis than the man on the street. \n\nSo what do we do instead? Math research proceeds along similar lines to the way that other academic disciplines make progress in understanding the things they try to understand. In fact, it's a lot like observational science, in that we proceed from observing certain phenomena about mathematical objects, to coming up with encompassing theories that explain why the patterns that we observe will always be the case. Generally, these phenomena or patterns are happening in mathematical objects that are more complex than the sorts of things that people meet in math classes up to calculus, but pretty much everything we study has its roots in high school math. \n\nFor instance, elsewhere in this thread someone who studies algebraic geometry has commented. These days, algebraic geometry is a formidably difficult and technical subject, but it's possible to give an indication of the flavor of the subject from just high school algebra. At its core, algebraic geometry is about treating solutions to polynomial equations as geometric objects. While this might sound abstract, it is in fact something that we all do in high school algebra! Any time we look at the graph of a polynomial equation (eg going from the equation x^2+y^2=1 to the circle that it describes) we are translating from algebra to geometry. And the moment you start asking questions like \"why do some equations give curves with \"corners\" (eg y^2=x^3) and some don't, like the circle?\" or \"how many points can two such curves intersect in?\" you are asking simple versions of some of the big questions that people who actually do algebraic geometry work on. Some of the work we do is about building new technical frameworks in which to answer these questions (in effect, developing new language to talk about the phenomena we are interested in); other times we see that we can answer some special case of a Big Question, or else we come across some new interesting patterns, and make an attempt to describe them and explain why they are happening. And ever so rarely, someone realizes that they have a feasible approach to one of the Big Questions. But this never happens in isolation; it always happens because of all the incremental work to clarify the previously poorly-understood ideas that go into the proofs. \n\nI hope this helps a little bit. I know I've definitely stayed on the extremely general end of the spectrum. One unfortunate reality is that you do need a lot of preparation to understand the technical definitions of a lot of the objects that we work with and think about, but I do think that it's always possible to give some flavor of what it is that we think about. ",
"There are a lot of interesting, famous problems listed here. But most research Mathematicians are working on way more specific things that would be difficult for anyone outside of their branch of Math to understand. Most of the time, they start with one person's result and try to stretch it a little bit to make it stronger. For instance, someone may have proven A, B, C implies D. Someone else may come along and say, you know what, I think A and B imply D. \n\nSource: Married to a Mathematician. ",
"[Related Question from Quora and Best Answer] *What do grad students in math do all day?*\n\nA lot of math grad school is reading books and papers and trying to understand what's going on. The difficulty is that reading math is not like reading a mystery thriller, and it's not even like reading a history book or a New York Times article. \n\nThe main issue is that, by the time you get to the frontiers of math, the words to describe the concepts don't really exist yet. Communicating these ideas is a bit like trying to explain a vacuum cleaner to someone who has never seen one, except you're only allowed to use words that are four letters long or shorter.\n\nWhat can you say?\n\n\"It is a tool that does suck up dust to make what you walk on in a home tidy.\"\n\nThat's certainly better than nothing, but it doesn't tell you everything you might want to know about a vacuum cleaner. Can you use a vacuum cleaner to clean bookshelves? Can you use a vacuum cleaner to clean a cat? Can you use a vacuum cleaner to clean the outdoors?\n\nThe authors of the papers and books are trying to communicate what they've understood as best they can under these restrictions, and it's certainly better than nothing, but if you're going to have to work with vacuum cleaners, you need to know much more.\n\nFortunately, math has an incredibly powerful tool that helps bridge the gap. Namely, when we come up with concepts, we also come up with very explicit symbols and notation, along with logical rules for manipulating them. It's a bit like being handed the technical specifications and diagrams for building a vacuum cleaner out of parts.\n\nThe upside is that now you (in theory) can know 100% unambiguously what a vacuum cleaner can or cannot do. The downside is that you still have no clue what the pieces are for or why they are arranged the way they are, except for the cryptic sentence, \"It is a tool that does suck up dust to make what you walk on in a home tidy.\"\n\nOK, so now you're a grad student, and your advisor gives you an important paper in the field to read: \"A Tool that does Suck Dust.\" The introduction tells you that \"It is a tool that does suck up dust to make what you walk on in a home tidy,\" and a bunch of other reasonable but vague things. The bulk of the paper is technical diagrams and descriptions of a vacuum cleaner. Then there are some references:\n\"How to use air flow to suck up dust.\"\n\"How to use many a coil of wire to make a fan spin very fast.\"\n\"What you get from the hole in the wall that has wire in it.\"\n\nSo, what do you do? Technically, you sit at your desk and think. But it's not that simple. First, you're like, lol, that title almost sounds like it could be sexual innuendo. Then you read the introduction, which pleasantly tells you what things are generally about, but is completely vague about the important details.\n\nThen you get to the technical diagrams and are totally confused, but you work through them piece by piece. You redo many of the calculations on your own just to double check that you've really understood what's going on. Sometimes, the calculations that you redo come up with something stupid, and then you have to figure out what you've understood incorrectly, and then reread that part of the technical manual to figure things out. Except sometimes there was a typo in the paper, so that's what screwed things up for you.\n\nAfter a while, things finally click, and you finally understand what a vacuum cleaner is. In fact, you actually know much more: You've now become one of the experts on vacuum cleaners, or at least on this particular kind of vacuum cleaner, and you know a good fraction of the details on how it works. You're feeling pretty proud of yourself, even though you're still a far shot from your advisor: They understand all sorts of other kinds of vacuum cleaners, even Roombas, and, in addition to their work on vacuum cleaners, they're also working on a related but completely different project about air conditioning systems.\n\nYou are filled with joy that you can finally talk on par with your advisor, at least on this topic, but there is a looming dark cloud on the horizon: You still need to write a thesis.\n\nSo, you think about new things that you can do with vacuum cleaners. So, first, you're like: I can use a vacuum cleaner to clean bookshelves! That'd be super-useful! But then you do a Google Scholar search and it turns out that someone else did that like ten years ago.\n\nOK, your next idea: I can use a vacuum cleaner to clean cats! That'd also be super-useful. But, alas, a bit more searching in the literature reveals that someone tried that, too, but they didn't get good results. You're a confident young grad student, so you decide that, armed with some additional techniques that you happen to know, you might fix the problems that the other researcher had and get vacuuming cats to work. You spend several months on it, but, alas, it doesn't get you any further.\n\nOK, so then, after more thinking and doing some research on extension cords, you think it would be feasible to use a vacuum cleaner to clean the outdoors. You look in the literature, and it turns out that nobody's ever thought of doing that! You proudly tell this idea to your advisor, but they do some back of the envelope calculations that you don't really understand and tell you that vacuuming the outdoors is unlikely to be very useful. Something about how a vacuum cleaner is too small to handle the outdoors and that we already know about other tools that are much better equipped for cleaning streets and such.\n\nThis goes on for several years, and finally you write a thesis about how if you turn a vacuum cleaner upside-down and submerge the top end in water, you can make bubbles!\n\nYour thesis committee is unsure of how this could ever be useful, but it seems pretty cool and bubbles are pretty, so they think that maybe something useful could come out of it eventually. Maybe.\n\nAnd, indeed, you are lucky! After a hundred years or so, your idea (along with a bunch of other ideas) leads to the development of aquarium air pumps, an essential tool in the rapidly growing field of research on artificial goldfish habitats. Yay!",
"I'm only a math PhD student, but here's an attempt at a different type of answer. There's a a website called the [arXiv](_URL_2_) for the online, free-access publishing of articles in physics, mathematics, computer science, and a few other computational areas. Literally everyone puts their papers up on the arXiv, and it covers a very broad range of subjects. To be precise, they list about 35 different subject divisions in mathematics, many of which are broad enough to contain dozens of diverse, active subfields.\n\n\nWhile I'm generally ignorant of most fields of mathematics, including the one I'm trying to study right now, I can often make a little sense of the abstracts of papers. I'm going to select 5 random, recently published papers (preferably published today) in very different areas of math and describe them based on a casual reading of their abstracts. These should give the flavor of the problems and ideas that most mathematicians think about, which often consists of working out very technical problems that have a small place in a larger theory.\n\n\nIt would be helpful if experts clarified and corrected my uneducated attempts to parse these abstracts.\n\n\n* Algebraic Geometry [Today]: [Indecomposable vector bundles and stable Higgs bundles over smooth projective curves](_URL_2_abs/1406.3839). Vector bundles are these constructions where you take some sort of shape and glue a nice type of space to each point. That space might be a line, a plane, or something higher-dimensional, but it is always \"flat\" in any event. This construction comes up very often if you want to study the geometry of the shape you started with. The author claims that if we restrict our attention to vector bundles of some elementary nature (in the sense that it cannot be broken up into simpler pieces) where the underlying shape is of a certain simple but common form, and if we further fix some characteristic of the bundles we are interested in (like if the spaces we glue have to be lines or planes or whatever), the number of such distinct bundles can be computed by a polynomial equation using the algebraic data of the underlying shape. Moreover, the author gives an explicit way to find the polynomial and connects this with the problem of counting another sort of geometric construction: Higgs bundles.\n\n\nAs you can see, I only gave a very vague description of the words I could understand, and even so it all seemed very technical and hard to parse. This is common in algebraic geometry. But the gist of it all should be clear. We want to count the number of a certain type of mathematical object, and the author provides a way to do that in a certain family of cases. The author also demonstrates that the answer to the counting problem is provided by a polynomial that requires us only to know a specific set of data about the shape we started with.\n\n\n* Number Theory [Yesterday]: [On the trace and norm maps from Γ0(p) to GL2(A)](_URL_2_abs/1406.3879). The author talks about modular forms. These are certain types of functions satisfying very nice symmetries which turn out to have remarkable connections to number theory, but I couldn't begin to tell you how (I haven't a clue). The author considers a particular type of modular form, called a Drinfield modular form, and then describes a way of taking a modular form for a certain type of symmetry and building two modular forms for a different type of symmetry. The rest of the paper show how the data of the original form is connected with the data of the two new forms.\n\n\nNumber theory is another technical subject that I don't understand, but the idea of this paper is how to move tools from one context to another, and what happens to those tools along the way.\n\n\n* PDE (Partial Differential Equations) [Yesterday]: [Fully nonlinear long-waves models in presence of vorticity](_URL_2_abs/1406.4096). PDEs are equations that describe the way some system is changing through space and time. The authors analyze the behavior of large-amplitude waves in shallow water when one considers the complicating effects of vorticity -- the way a fluid spins. The problem seems to involve three independent dimensions of space and time but they manage to reduce it to a collection of two-dimensional problems which are easier to solve. Then they go on to talk about some of the additional technical features of this simplification technique they have developed.\n\n\nThis sort of paper is common in PDE. The authors take a very complicated physical situation and attempt to understand the behavior of a specific case (large amplitude, shallow water) with the presence of an additional complicating effect (vorticity). The task then becomes to show that the associated physical phenomenon has some nice dynamics and regularity properties: that is, it doesn't go crazy.\n\n\n* Logic [Today]: [Finitary reducibility on equivalence relations](_URL_1_). An equivalence relationship is a way of dividing a collection of objects into groups of things that are similar in some way. You might divide up a class into boys and girls, or the socks in your draw by their color. Another example is dividing up the whole numbers into the even and odd numbers. This paper talks the problem of comparing two such \"equivalence relations\" in a way that might make sense to a certain sort of computer. They claim that their comparison method has advantages over traditional comparison methods. For one, it allows one to talk about relations that are the \"most complicated\" in some context. They then go on to show that their comparison method is well suited for distinguishing things of arbitrary complexity, and apply their techniques to certain well-known equivalence relations. Lastly, they use their techniques to show that a certain well-known result cannot be extended.\n\n\nI don't know if this sort of problem is common in logic, but the authors are essentially trying to introduce their own way of comparing the complexity of \"equivalence relations\" and show that it has nice theoretical properties.\n\n\n* Statistics [Yesterday]: [Finding an ARMA(p,q) model given its spectral density or its correlogram](_URL_0_). An ARMA(p,q) model is a model for predicting the behavior of a sequence of events that seem to behave randomly within the guidelines of certain probabilistic behavior. One application might be economic data, such as stock prices. The ARMA model describes the way the average changes over time, as well as the way current events are related to past ones. Given such an ARMA model, one can look at information like its spectral density, which describes how it varies in different frequencies, and also at the various correlations it predicts. This gives three ways of thinking about the model: the spectral density, the correlations, and the original ARMA description involving the averages and the past relations. The author describes how to move between these three different perspectives.\n\n\n---\n\n\nLet me just say that the above descriptions are very poor and simplified (in accordance with my limited understanding and the sheer amount of words it would take to be much clearer). I also have only covered about a quarter of what might constitute a proper sampling of the various branches of math, including the area I study myself. Please let me know if you have questions or want me to look at a paper from a specific branch in mind."
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30r0so | what is the rationale for why we need to increase defense spending? | So apparently Tom Cotton and Marco Rubio presented a plan to increase defense spending, but aren't offsetting the increase with cuts elsewhere. This is odd considering Republicans are all about fiscal responsibility. Rubio says that defense is too important to get caught waiting for cuts to go through elsewhere when we need to increase the budget NOW. My question is, why do we need to increase the budget? Why is the need so dire? Currently we only use a fraction of our troops in the middle east because of the pullback, so we aren't exactly using all of our resources now anyway. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/30r0so/eli5_what_is_the_rationale_for_why_we_need_to/ | {
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"Because defense contractors get their profits from selling bullets, bombs, building cities, yada yada from the war effort. You really didn't know that?",
"I find it a little obnoxious that you just say 'we' like only Americans use Reddit"
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963ytn | if every living human body disappeared off the face of the earth all at once, would anything happen to the planet's orbit? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/963ytn/eli5_if_every_living_human_body_disappeared_off/ | {
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"Yes! There would be change in the orbit of the Earth.\n\nThe Earth does not technically orbit the Sun, rather, the two objects orbit a common point in space, called the barycenter, about 450km from the center of the Sun. (still *well* within the Sun, but the Earth causes a 450km \"wobble\" of the Sun)\n\nIf all humans were to vanish, the barycenter would change by about 30 nanometers."
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bu53a6 | what, exactly, happens to the body of the climbers in "the death zone" (i.e. on mount everest) that causes their death? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/bu53a6/eli5_what_exactly_happens_to_the_body_of_the/ | {
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"There is not enough oxygen in the air at that altitude to keep a human alive. Climbers carry oxygen in bottles, to supplement the air they breathe. Without enough bottled oxygen, they suffocate.",
"Some of the biggest factors are called HACE and HAPE; high-altitude cerebral edema and high-altitude pulmonary edema. Both of them involve fluid accumulating in a place where it shouldn't due to the body's stress at high altitudes - for HACE, fluid is accumulating in the brain, causing confusion and disorientation, while for HAPE, it's accumulating in the lungs causing shortness of breath. And when you're up on a mountain fighting exhaustion, weather, and the climb itself, either of those can prove quickly fatal. I believe that HAPE-related deaths are one of the most common, specifically, at high altitude.\n\nAnd the scary thing about HACE and HAPE is that they can seemingly happen to anyone, anytime at high altitude. Being physically fit and acclimating to altitude slowly seem to reduce the chances, but even some of the most fit and prepared mountain climbers have died due to those conditions. If you've ever seen the movie *Everest* or read *Into Thin Air,* about the 1996 disaster on Everest, they note that Gary Ball, one of the founders of the Adventure Consultants company, died a few years before that disaster due to HAPE - and he was one of the most physically fit and well-prepared mountaineers in the world. Some of the guides and mountaineers who died on Everest that day were showing possible signs of HACE, possibly impacting their abilities to make decisions and move effectively.",
"There's only about 30% of oxygen in the death zone, when compared to sea level. As altitude increases, the amount of oxygen decreases (also why planes are pressurized, because otherwise you wouldn't have enough oxygen). With the amount of available oxygen in the death zone, you literally can only survive a few minutes. Every moment you are within the death zone, you are slowly suffocating and your cells are dying. This also increases your heart rate(your body trying to get the oxygen from your blood faster), which can increase your chance of heart attack and of stroke.\n\n & #x200B;\n\nRight now, people are dying on Everest because they are waiting for the summit and it is too crowded to go at their normal pace.",
"Falling, hypothermia, hypoxia, high-altitude cerebral edema, high altitude pulmonary edema...take your pick. In the death zone specifically, hypoxia (lack of oxygen) and its effects are common causes of death. Above 8000 meters, there's simply not enough oxygen for humans to survive. Climbers in the death zone without supplemental bottled oxygen are slowly suffocating every minute they spend at this extreme altitude.",
"The air is thinner the higher you go. Above a certain altitude, the air is so thin that each breath of air provides less oxygen than the body needs to survive. Most hikers up Everest bring oxygen tanks to breathe from for that portion of the mountain, but if they don't, their body will gradually use up the oxygen in their blood. Eventually, the cells of the body will die after being deprived of oxygen for too long, and while the body will attempt to prioritize oxygen to the brain, eventually the brain or some other vital organ will have too little oxygen for too long and begin to die off, leading to the person dying."
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l3m28 | what do these things do individually in our bodies? | Please explain what the following *actually* do in our bodies:
* carbohydrates (simple and complex)
* fats
* proteins
| explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/l3m28/eli5_what_do_these_things_do_individually_in_our/ | {
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"I am far from an expert, but hopefully this will suffice.\n\nCarbohydrates are metabolized into simpler carbohydrates through a process called [hydrolysis](_URL_0_) as your body needs energy. These simple carbohydrates are then converted into even simpler organic molecules, \"releasing\" energy for your body to use in the process.\n\nCarbohydrates that your body doesn't immediately need are combined by \"dehydration synthesis,\" sometimes (in BIO 101 lectures, anyway) considered the opposite of hydrolysis, into fats, which are stored all over your body for later use. Fats that you eat directly are also stored in this way unless your body needs them immediately, in which case they're hydrolyzed into simple sugars right away.\n\nProteins, unlike the other two, are made from polypeptides (rather than glycerides), which are in turn made from amino acids. Peptides and amino acids are used all around the body for different processes, including muscular development.",
"If you're familiar with the idea of a polymer, you already basically know what a protein is. Proteins are (usually) large, complicated molecules that are made of combinations of smaller molecules (amino acids). Different Proteins have different jobs, but most of the material that makes up the structures in your body is protein. There are so many different kinds it's hard to describe them all in detail, but it's kind of like saying, \"There are 26 letters in the alphabet. You can combine them into many different words, some simple, some complex, all with a unique purpose.\"",
"Carbohydrates: Basically long strings of sugar molecules put together. Carbohydrates are consumed to provide easy short-term energy for fast-twich muscle activity like sprinting and lifting heavy things.\n\nFats: Containing much more overall energy than carbohydrates, but more difficult to break down, fats are burned to generate a steady supply of energy at low-medium levels for slow-twich muscle movement like walking, jogging, heartbeats etc.\n\nProteins: Used kind of like fats sometimes, but most importantly used to build muscle cells. Proteins can be used for a multitude of things but their most important functions all pertain to cell construction and operation. the general term \"Protein\" usually refers to meat, whereby you get the raw materials needed to build muscle.",
"I am far from an expert, but hopefully this will suffice.\n\nCarbohydrates are metabolized into simpler carbohydrates through a process called [hydrolysis](_URL_0_) as your body needs energy. These simple carbohydrates are then converted into even simpler organic molecules, \"releasing\" energy for your body to use in the process.\n\nCarbohydrates that your body doesn't immediately need are combined by \"dehydration synthesis,\" sometimes (in BIO 101 lectures, anyway) considered the opposite of hydrolysis, into fats, which are stored all over your body for later use. Fats that you eat directly are also stored in this way unless your body needs them immediately, in which case they're hydrolyzed into simple sugars right away.\n\nProteins, unlike the other two, are made from polypeptides (rather than glycerides), which are in turn made from amino acids. Peptides and amino acids are used all around the body for different processes, including muscular development.",
"If you're familiar with the idea of a polymer, you already basically know what a protein is. Proteins are (usually) large, complicated molecules that are made of combinations of smaller molecules (amino acids). Different Proteins have different jobs, but most of the material that makes up the structures in your body is protein. There are so many different kinds it's hard to describe them all in detail, but it's kind of like saying, \"There are 26 letters in the alphabet. You can combine them into many different words, some simple, some complex, all with a unique purpose.\"",
"Carbohydrates: Basically long strings of sugar molecules put together. Carbohydrates are consumed to provide easy short-term energy for fast-twich muscle activity like sprinting and lifting heavy things.\n\nFats: Containing much more overall energy than carbohydrates, but more difficult to break down, fats are burned to generate a steady supply of energy at low-medium levels for slow-twich muscle movement like walking, jogging, heartbeats etc.\n\nProteins: Used kind of like fats sometimes, but most importantly used to build muscle cells. Proteins can be used for a multitude of things but their most important functions all pertain to cell construction and operation. the general term \"Protein\" usually refers to meat, whereby you get the raw materials needed to build muscle."
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1qzat8 | why does kissing make us... horny? | Why do people get aroused by the act of kissing? I mean, why is it hot to do so? I want to get the science behind it!
This isn't a question a 5 year old would make but what the hell, I'll ask it anyway!
| explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1qzat8/eli5_why_does_kissing_make_us_horny/ | {
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"Your lips are very sensitive to fine touch, and for a lot of people, they are erogenous zones, meaning that certain stimulation can turn you on. It's the same reason why some people are sensitive to things like sucking on earlobes.",
"Your body reacts based on your knowledge and prior experiences: You expect that the person who kisses you finds you attractive and wants to do more than that. So you get horny. If high fives were a sign of affection in a different culture people would get horny after that too."
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9q3czt | how is the country (united states) with the largest deficit also the world's largest "super power"? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/9q3czt/eli5_how_is_the_country_united_states_with_the/ | {
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"Superpower refers to military strength. \n\nI think you mean debt instead of deficit (correct me if I’m wrong). Even though our debt is high, our GDP is massive. As producers and consumers, the US still dwarfs other nations. "
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a2wrpu | why do helium-3 and deuterium in nuclear fusion produce 1 helium and an extra proton, instead of lithium which has 3 protons | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/a2wrpu/eli5_why_do_helium3_and_deuterium_in_nuclear/ | {
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"It will form Lithium-5 initially, but Lithium-5 is exceptionally unstable with a half life on the order of 10^-24 seconds. All the lithium-5 that is formed quickly releases a proton and decays to stable Helium-4"
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1j2m52 | why is russia divided into several oblasts, krai, and republics instead of just states or provinces, and what is the difference between a krai and oblast? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1j2m52/eli5_why_is_russia_divided_into_several_oblasts/ | {
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"It's just the Russian equivalent of a State or Providence. They can be used interchangeably. \n\nMany people do that realize this but many American states are legally called commonwealths. A commonwealth is no different than a state but the name was chosen to be used in place of state. For example Massachusetts is a Commonwealth, New York is a State, both are considered defined legal areas for local jurisdiction. ",
"There is no significant difference between a krai and an oblast, both on a legal level as well as in practice.\n\nRepublics have more legal rights, in that they can define their own official languages and have their own constitution and legislature. Russia is legally the Russian Federation, so these republics are nation states within the Russian Federation.\n\nIn the Russian constitution, republics are defined as states and are meant to be regions for certain ethnic minorities. So the Chechen Republic (or Chechnya) is a federal subject of the Russian Federation, and yet it has its own official language, government, constitution, legislature and an ethnically non-Russian majority of the population. It is much like a state in itself, so much so that someone from Chechnya would be called Chechen, not Russian.\n\nThere are also autonomous okrugs, which have a predominant ethnic minority and some improved legal rights, including the ability to participate in international and federal agreements and contracts independently.\n\nMoscow and Saint Petersburg function as separate federal subjects (federal cities)."
]
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[],
[]
] |
||
628vi5 | why is it easy to tear paper in half but not to pull it apart? | Paper is super easy to tear in half, but it's incredibly difficult to pull apart. I imagine it has something to do with an increased number of bonds I'm trying to break simultaneously, but I can't find anything on the topic. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/628vi5/eli5_why_is_it_easy_to_tear_paper_in_half_but_not/ | {
"a_id": [
"dfkosl6",
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"score": [
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3,
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"text": [
"You've stumbled onto a key concept in engineering, which is the difference between [normal stress](_URL_1_) and [shear stress](_URL_0_).\n\nIn normal stress (tension or compression), you're pushing or pulling in line with the atomic bonds, like pushing/pulling on a spring. In shear stress, you're forcing lines of atomic bonds to slide *past* one another (like pushing a spring sideways), so you're not fighting them directly. Most everyday materials are less resistant to this sort of stress - paper is a great example. It's far too strong against tension for you to pull apart. But it can be easily torn or sliced by a shear load.",
"That's exactly the case. If you tear (or cut with scissors, knife, etc) you're applying a force to a very small area to break those bonds, whereas if you try to gather it up and pull it apart, there's quite a few more bonds to break simultaneously, so the force will need to be proportionally greater.",
"Imagine having 1000 threads of string. Now put all these threads together and try to pull them apart. Now take a single string and pull it apart, but do that 1000 times. The latter is much easier.\n\nWhen you pull apart a sheet of paper you are trying to snap all the fibers at once. When you tear the paper you break one fiber at a time."
]
} | [] | [] | [
[
"https://en.wikipedia.org/wiki/Shear_stress",
"https://en.wikipedia.org/wiki/Stress_(mechanics\\)"
],
[],
[]
] |
|
23hi72 | why aren't all dreams lucid? | Yes I realize some people are natural lucid dreamers | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/23hi72/eli5_why_arent_all_dreams_lucid/ | {
"a_id": [
"cgx1qu3",
"cgx1ta7"
],
"score": [
2,
2
],
"text": [
"Because the part of the brain that controls logic is pretty much off. If it was on all the time we would realize how odd it is to be flying or whatever. It's when we become aware of the bizarre that we stop and think, \"I must be dreaming\". ",
"I need to do more reality checks."
]
} | [] | [] | [
[],
[]
] |
|
3426we | why do we have a saying for when someone sneezes, but not for when someone hiccups? | I just came back from filling up my water when the girl waiting behind me started hiccuping. It seemed awkward to have nothing to say for the whole minute that she was waiting for me to finish. Maybe I'm just too awkward as a person, but I feel like it would go a long way if we had some saying to acknowledge someone's hiccup without sounding invasive. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/3426we/eli5_why_do_we_have_a_saying_for_when_someone/ | {
"a_id": [
"cqqj3cb"
],
"score": [
7
],
"text": [
"Hiccups have never been an indication of impending death, a sneeze has, though. There was a time when plagues and diseases were ravaging whole countries and killing millions. A sneeze was not only an indication of possible sickness but even death. God bless you really does go back that far."
]
} | [] | [] | [
[]
] |
|
afiu7v | what exactly is the difference between chilblains and frostnip? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/afiu7v/eli5_what_exactly_is_the_difference_between/ | {
"a_id": [
"edyyoih"
],
"score": [
5
],
"text": [
"Frostnip is a precursor to frostbite and is caused by ice crystals forming under the skin.\n\nChillblains are caused by a circulation problem in small capillaries due to cold but not necessarily freezing temperatures."
]
} | [] | [] | [
[]
] |
||
4fppjf | how do the deaf understand techno? | [deleted] | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4fppjf/eli5_how_do_the_deaf_understand_techno/ | {
"a_id": [
"d2awik0"
],
"score": [
6
],
"text": [
"Loud music, particularly bassy loud music creates waves in the air that can be felt, rumbles in the floor, etc. Raves also have lots of interesting lighting and people. They think it's fun and interesting. What greater \"understanding\" of techno do you think there is?"
]
} | [] | [] | [
[]
] |
|
bnu2s4 | how skyscrapers are built | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/bnu2s4/eli5_how_skyscrapers_are_built/ | {
"a_id": [
"en95kbu"
],
"score": [
4
],
"text": [
"You dig a deep pit until you hit bedrock, form the substructure of the skyscraper using beams and build the structure of the rest of the skeleton. Generally they will have a single core for the building made of reinforced concrete with thick steel beams and girders. \n\nFrom the core you will brace the building with more beams and build the floor space. Depending on the location and size of the building you will need reinforcements in the form of dampers to prevent excessive movement at the top and against environmental effects."
]
} | [] | [] | [
[]
] |
||
1yd8zc | why can't other large companies set up their own internet service that is wifi based? | I am not talking about providing service for all America - rather to the more populated areas - thus I feel that WIFI could reduce all the cost of wiring to individual homes.Like WIFI for NYC? Can that service be viable? I know there still lies the cost of big infrastructures, wires, admins, engineers etc - but I think it would cost less wiring every home. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1yd8zc/eli5why_cant_other_large_companies_set_up_their/ | {
"a_id": [
"cfjfyiu"
],
"score": [
2
],
"text": [
"* That's not what their business is\n\n* It's a MASSIVE investment for a comparatively small return\n\n* Even if you are able to solve all the current problems with long-distance WiFi connections (Look at LTE. It's the best we've got right now and I still wouldn't trust it for all the internet usage I go through), it's still going to have to be hard-wired into the rest of the internet at some point on the line, and running all that cable is extremely expensive. Not to mention all the permits and policies and everything you have to go through to get connected to one of the internet backbone sites."
]
} | [] | [] | [
[]
] |
|
3djjqb | what is the sputtering sound tractor trailers make when slowing down ? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/3djjqb/eli5_what_is_the_sputtering_sound_tractor/ | {
"a_id": [
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"text": [
"Engine braking. No fuel comes into the cylinders and the engine acts as a compressor. What you hear is the sound of air in the exhaust. ",
"Possibly what you are hearing is jake braking or engine braking as its callex in some places. Its a way to slow down that reduces wear on the standard braking system",
"Yeah, I just always thought it was downshifting, which definitely slowed my stick shift car down real fast. . .",
"What the other responders said. You will sometimes see signs on the freeway in major metropolitan areas that say \"No Jake Brakes\" or \"No Engine Braking\" or similar. Its prohibiting that noise, because its really loud.",
"This answered a question I never knew I really had. I went and found [this video](_URL_0_) which seems to illustrate the concept well enough."
]
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[],
[],
[],
[],
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"https://www.youtube.com/watch?v=7FSkNSOeTWM"
]
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||
2i5ztf | why were hops ultimately chosen as the go-to beer "seasoning," now used almost exclusively instead of spice sachets, etc.? | I enjoy a good beer, but hops give me awful headaches. My understanding is that in ye olden times brewers often used spice sachets (of things like clove or cinnamon) to take the bite out of their brews, and that "seasoning" with hops was just one style. Nowadays the vast majority of beers are hop-style, and it seems like only around the holidays (with the arrival of pumpkin ales) can I reliably find beers that aren't brewed with hops.
Why were hops ultimately chosen as *the* beer "seasoning," and the other spiced varieties more or less abandoned? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2i5ztf/eli5_why_were_hops_ultimately_chosen_as_the_goto/ | {
"a_id": [
"ckz62r6",
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"score": [
3,
3,
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"text": [
"two main resons:\n\ntaste. people just like hops more than [Gruits](_URL_0_).\n\nhop is antiseptic, contrary to herbs, so you can eliminate some bacterias with it, what is especially important in non-pasteurized beers.",
"This is blasphemy. \n\nSeriously though, that was a joke, everyones has different tastes. I prefer IPA/PA for the most part...but like all kinds of beer.\n\nHave you tried the wheat beers like Blue Moon/Shock Top/Hoegaarden with a slice of orange? Have you ever seen/tried Pyramid Apricot Ale? None of these taste remotely hoppy to me, but I have a high tolerance so to speak. \n\nEDIT: I forgot to answer your question so I think that they chose to roll with hops traditionally because they are so incredibly tasty as fuck.\n Also, they overhopped the shit out of beer so when they shipped ale overseas it didnt get funky or lose all the tasty hoppy flavor. Cause its the good stuff ",
"Hops act like a natural preservative of sorts. People started to notice that hopped beers lasted longer, so it became a vital ingredient. Just fyi, those seasoned beers you like most likely have hops, just like 99% of beers out there. If you dislike hops, but like flavorful beers, look for malty types or wheat beers.",
"Some beers get flavoring from other \"normal\" agents like smoking the grain with peat (Scotch Ales).\n"
]
} | [] | [] | [
[
"https://en.wikipedia.org/wiki/Gruit"
],
[],
[],
[]
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|
2q0kmg | why does the nba have franchises in such odd locations, while mlb and nfl mostly cover the same cities? | There are NBA teams in Portland, San Antonio, Oklahoma City, Memphis, Salt Lake City, Sacramento, and the Hornets started in Charlotte seven years before there was an NFL team there. Meanwhile more traditional sports markets such as St Louis, Pittsburgh, Tampa, Cincinnati, and Baltimore don't have teams. Why is this? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2q0kmg/eli5why_does_the_nba_have_franchises_in_such_odd/ | {
"a_id": [
"cn20is3"
],
"score": [
2
],
"text": [
"It has to do with the history of the NBA vs the ABA. NBA formed first, putting teams in the cities you'd expect. ABA formed second and put teams in places without teams already (by definition, *not* the typical cities to have teams). When the two leagues merged in the 70's, some ABA teams remained, which is why there are still several teams in cities that other leagues don't have teams in."
]
} | [] | [] | [
[]
] |
|
ao3rny | why do game developers always seem to overdo it when it comes to balancing games? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/ao3rny/eli5_why_do_game_developers_always_seem_to_overdo/ | {
"a_id": [
"efxx9ha"
],
"score": [
3
],
"text": [
"with major changes, it pushes forward a new meta, new strategies, new ways to attack and defend. It the best weapon gets tweaked with just minor tweaks, people will most likely still use it in the same fashion, but if they nerf it to bits, suddenly people will actually have to go out and find new ways to do shit"
]
} | [] | [] | [
[]
] |
||
1limsi | why is syria potentially america's problem, and not the un's? | I understand that other countries, like Russia for example, can make things more complicated, but shouldn't the use of chemical weapons on its own people be a good enough reason for the UN to get involved, simply from a human rights standpoint? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1limsi/eli5_why_is_syria_potentially_americas_problem/ | {
"a_id": [
"cbzm2j0",
"cbzntho"
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"text": [
"It is quite possible that it is the other way around, i.e. America is the problem for Syria, not the opposite. \n\nBefore US started to train and finance insurgents the place was just another shitty dictatorship. It was even hoped that the proliferation of the internet and social media would increase demand for more democratic society. Unfortunately when you inject arms and military training into a troubled country you inevitably get a civil war. US exploited that, possibly precluding the hope of normalization for the next 50 years or more.\n\nedit: typo",
"The UN is pretty powerless most of the time. In this case, Russia, a close ally of Syria, doesn't want the UN to intervene, and they have veto power.\n\nThe list of humanitarian crises where the UN couldn't intervene, or didn't until it was too late, is quite long. It usually comes down to power struggles and political squabbling."
]
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[],
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yuqs9 | starcraft and its culture | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/yuqs9/eli5_starcraft_and_its_culture/ | {
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"text": [
"By culture, I'm assuming you're referring to the growing e-sports movement that started in Korea and is now spreading over the world?\n\nEssentially, Korea at one point was in the middle of a great depression of its own. (You can google the Asian Financial Crisis for more). In the midst of this financial crisis, many people didn't have much to do, and even less money to do what they wanted to do. As a result, they turned to something really cheap: video games. You see, in Korea, there are many PC cafe's, called PC bangs, where you can play video games for really cheap. It also helped that Korea was one of the first countries to develop faster Internet, leaving behind dial-up connections. \nMuch of Korea's youth spent their time playing video games, such as Starcraft, because realistically, there wasn't much else to do that they could afford.\nAfterwards, a lot of people felt like Starcraft was one of the important things that got them out of the recession, and one person decided to connect a couple of computers and broadcast a match between two players. After all, it's a lot more fast-paced then soccer or basketball, and when you have anxious Korean commentators screaming at every moment, it gets pretty tense.\nFast forward a couple of years, and Starcraft has gained a huge fanbase. Pro-players (yes, they need a license) have the same following as football athletes here in Canada/USA or wherever you live. The tournaments and stadiums they have set up for these games is pretty top-notch, and there are at least two TV stations that broadcast Starcraft games 24/7. To have a career of a progamer, you must win first place at at least two of these \"scouting\" type tournaments, sort of equivalent to every year's draft pick by the NBA. And they make a fair amount of money too. One of the most successful Starcraft players, \"SlayerS_BoxeR\" made about 100,000 USD per year, not including the many endorsements that he received from various companies.\n\nAnyways, it's been a while since I've checked into the Starcraft scene. Some of my facts may be a little off, but you get the general idea.",
"Starcraft is a real-time strategy game for the PC, originally released in the late 90s. It was created by Blizzard Entertainment, also known for the Warcraft and Diablo series. Starcraft II was released a couple years ago after a 10+ year hiatus. The game revolves around collecting and using resources to create an army and a military base with which you destroy your opponent. If you've played Warcraft, Age of Empires, or any other RTS game it's relatively similar. \n\nBy culture I'm going to assume you mean the eSports scene and the obsession around it. As with any competition, the only real \"start\" to it was when people started gathering together to play. As the game got more popular and the skill level of the players increased, the events themselves increased. Over time, the events got large enough that tech companies started sponsoring players or teams of players to go to these events and compete, similar to how Nike or Addidas might sponsor a cyclist or a tennis player. In return for some sort of payment, the player might wear a patch from that company on their jersey, or give small shout-outs to them if they win. The game comes with a built-in spectator mode where a non-player can view the whole map, different stats about each player, and other cool things you can't do while you're playing. Since most people are not actually at the event, having an \"observer\" moving the camera around the map to important battles and things is important, otherwise the people at home won't know what's going on. Similarly, events will hire or sponsor \"casters\" to come and give sports like play-by-play and strategy commentary on the game. Generally casters are former or current players who simply like the game a lot, similar to how a football commentator might be a former quarterback. Most of these events are streamed online nowadays, with thousands of viewers watching players from all over the world compete for cash prizes, bragging rights, or invites to other tournaments. That's the basic run-down. I skipped over the whole Korea vs. Everyone else thing because it's not as important to a basic understanding, as long as you know that South Korea has a very long history and engrained culture around Starcraft, and has the best players in the world for the most part. Everyone is else is usually called a \"foreigner\" if they're not from Korea.\n\nAlso [check this thread out for more posts/info](_URL_0_)",
"I'd like to add a question to this thread if I may: \n\nHow long does the average match last? are they quick bouts or long drawn out affairs, how do they keep content fresh are there hundreds of maps or variables, or just an array of tactics to any one scenario? \n\njust curious. ",
"_URL_0_\n\nAlso, if you don't mind the read, TIME Magazine wrote an excellent article about this."
]
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"http://www.reddit.com/r/explainlikeimfive/comments/myv9f/why_is_starcraft_2_so_massively_popular_and_how/"
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[],
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"http://www.time.com/time/specials/2007/article/0,28804,1815747_1815707_1815675,00.html"
]
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||
3gigmv | why can't hiv be treated with chemo therapy | Why can't HIV infection be treated with chemo therapy and bone marrow transplant? When people receive an allogeneic BMT (Bone marrow from donor) or Autologous BMT (from their own stem cells) they have to undergo reimmunisation because they lose immune memory which was acquired from exposure and vaccines. So why doesn't this work for HIV infections? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/3gigmv/eli5why_cant_hiv_be_treated_with_chemo_therapy/ | {
"a_id": [
"ctyf98o"
],
"score": [
2
],
"text": [
"I'm confused as to why you think it would be. The virus is still there. It would just attack the new T-cells. Chemotherapy specifically targets rapidly growing cells. Viruses are not cells and wouldn't be effected by a chemotherapy treatment."
]
} | [] | [] | [
[]
] |
|
fy3jx2 | what is the difference between a wet market and a farmer's market? | [deleted] | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/fy3jx2/eli5what_is_the_difference_between_a_wet_market/ | {
"a_id": [
"fmy2qcx",
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"score": [
12,
2
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"text": [
"A wet market is just slang for a market that sells perishable goods. When people say wet market they usually mean markets that sell live animals for food and either slaughter it for you or sell it to you live. Most farmer's markets just sell produce and meat.",
"While the other comments get the exact details history is on order to understand why wet markets are so stigmatized.\n\nIn the 1970s the Chinese were facing mass starvation of 500 million people. The communist government as communists always do tried to preserve itself. So it legalized hunting and made the sale of the killed game profitable by making it private property. People in China, eating pandas and other wildlife were worried about the quality so they demanded it be live and to watch it being killed. This caused the epidemic of 1984 that didn't spread to the rest of the world because of China's issolation at the time. The government's response was to regulate the sale and force all of the sales into wet markets. (Instead of ending it)\n\n5 times now the wet markets have created epidemics and pandemics yet the markets reopen because without them China starves.\n\nHence the stigma aside from eating bats, dogs, bears, and Chinese armadillos. Until the end the practice we'll continue to have these diseases come from the region."
]
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[],
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|
vlpbp | why do some stalkers want to kill their idols that they love so much? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/vlpbp/eli5_why_do_some_stalkers_want_to_kill_their/ | {
"a_id": [
"c55k5f3",
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"score": [
11,
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"text": [
"There is probably a better explanation of it but it's sometimes something along the lines of \"If I can't have you then no one can\"",
"They will be a part of the idol's history forever.",
"Sometimes, people don't act the way you expect them to. \n\nYou know how when you love someone you want to protect them, right? Well, when you're not exactly \"normal\", you might view love differently.\n\nSometimes, when someone that's \"not normal\" realizes that someone they love might not love them back, their emotions become so strong that they don't know what else to do but get rid of what's confusing them. It's very sad when it happens.",
"Stalking usually isn't about love. It's more commonly about control. Stalkers tend to become obsessed with the control of their victims and their lives. And the most extreme way to control someone else's life is to end it.\n\nIt's certainly not this logical or simple in the real world, but this is a short answer that I think captures the basic idea of the situation. I think the flawed assumption here is that stalking stems from something like love. That's certainly not the case."
]
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[],
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||
7f556h | what is the reason that some electrical devices with huge voltage ratings don't kill you, and what are the electrical properties that cause this? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/7f556h/eli5_what_is_the_reason_that_some_electrical/ | {
"a_id": [
"dq9kxfq"
],
"score": [
2
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"text": [
"For an honest to God five year old, I'd say voltage is like the mass of the electricity moving, amps are the speed. If a semi truck bumps into you, you'll be fine, whereas a bullet that has orders of magnitudes less mass but plenty of speed will cause you trouble. I'm no electromagician though. "
]
} | [] | [] | [
[]
] |
||
3a62yx | why is everyone making such a big deal about hillary clinton's emails? | It's something about the Benghazi attack three years ago? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/3a62yx/eli5_why_is_everyone_making_such_a_big_deal_about/ | {
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181,
20,
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"text": [
"Because she didn't do what she was supposed to, instead of using her government email account, she used her person email. A lot of people take that as she has things she wants to hid.",
"Edit: it was pointed out to me that at the time of Clinton's tenure in office, using a government issued email wasn't legally required, only strongly suggested.\n\nGovernment employees, especially high ranking ones, are required to use official government email addresses and servers for their work related issues. \n\nThere are two reasons for this, one is for security purposes, and two is for accountability and transparency. Basically they don't want another government or group trying to hack into unsecured emails containing sensitive information, and they want to make sure that somewhere down the road those official emails can be retrieved and reviewed. \n\nSo it came to light some time ago that Ms. Clinton was using her private email address to send official emails, which is a pretty big security breach, and is somewhat suspicious. It's a pretty tough line to sell that it was accidental, seeing as Ms. Clinton has held a government job for about as long as email has been in regular use.\n\nThat brings up the question of why. I'm no conspiracy theorist, nor am I fan of the Republicans, but I can't think of a good reason for this situation to have happened.",
"There are laws regarding data storage, retrieval, archival, etc. Think about a brokerage firm. They have to keep so many years of documentation on file, available for immediate retrieval. That's just for proving John Smith really wanted to sell 5 shares of Apple.\n\nNow imagine you're the top foreign official for the United States of America, and you're using e-mail to conduct communication with foreign nations, and other government officials. It's important someone has access to that stuff. \n\nThe reason given for why she broke the rules was \"It's too hard and complicated.\" and she didn't want to have to carry two phones. Her argument is that somehow, it's less complicated to hire someone to set up a private mail server in your house that no one else can get to, monitor, or archive than it is to use the e-mail address system that they give you that is already set up. \n\nAlso, like /u/riconquer said, the government servers/systems are set up to be as secure as possible. If you're running your own system on in your garage, there's no way for anyone else to know how secure the data they're sending you is. She could be have been sending highly sensitive information insecurely, or had inadequate intrusion protection which is a huge risk. ",
"Also, they could contain information regarding some suspicious foreign donations to the Clinton Foundation.",
"It's an anti-corruption thing. She could be hiding things like shady deals in exchange for campaign donations or prior knowledge of Benghazi dangers. If you want your government to be accountable and free from corruption, then you don't want to see them hiding and deleting official communication.",
"To my understanding (at least this is how I personally feel), a white house official using a private server for what is supposed to be public info and losing scores of emails is sketchy and untrustworthy. While the GOP candidates are also really sketchy, Clinton has *already* been a member of white house staff. Corruption is not limited to the extreme right, and just because she is a Democrat does not excuse her from transparency. I feel that politicians must be transparent, responsible, and accountable. \n\nI don't watch the news enough to tell you why she's getting so much attention, but thats why I don't personally trust her."
]
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|
pqmk5 | how could mj have been so broke if he owned the rights to all the beatles songs? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/pqmk5/eli5_how_could_mj_have_been_so_broke_if_he_owned/ | {
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"text": [
"Ridiculous purchases and not paying his debts. There's always going to be more and more ridiculous things to spend money on. ",
"Being broke for fabulously wealthy people isn't always the same kind of being broke as it is for us commoners. Also, MJ would shop like he still was producing top selling albums when he hadn't done so in a while.",
"Besides the whole irresponsible spending thing, one thing a lot of people don't realize is how much the rich and famous get pitched for bad investment ideas. I think it was Mark Cuban who said he gets hundreds of letters and emails a day asking for money for the \"next Facebook\" or \"next Google\" or \"next pet rock\" or whatever. You can imagine someone who's rich but not financially sophisticated buying into some of the slicker venture capital pitches out there and sinking a lot of cash into a bad product. ",
"Michael Jordan? @_@",
"He didn't own all of the Beatles songs. He owned half of the rights (publishing) to MOST of the McCartney-Lennon songs; McCartney and Lennon still owned the other rights (songwriting) of their catalog and their respective estates still do to this day. Some earlier songs (a couple of hits, mostly throwaway stuff) were excluded from this deal because they were owned by another publisher from the Beatles early days, and George Harrison's song were never part of this deal.\n\nI think he bought the publishing rights to this particular catalog for about $50M US in the early 80's. His deal was further diluted when he sold half of his half to Sony for something close to $100M US in the mid 90's, a nice return if you consider the valuation. I even remember reading that he borrowed more money from Sony using his remaining 25% (half of half) share as collateral against future earnings. I think they loaned him something like $300M US. That technically put Sony in the driver's seat for controlling publishing of the Beatles catalog. I have no doubt that he probably would have made good on the loan from Sony eventually, but I don't know what kind of terms they were able to squeeze him with. All they knew is that he was desperate for money and would probably default and then it's theirs 100%.\n\nI just [read])_URL_0_) that the most recent valuation of HIS share of the Sony deal was close to $400M US.\n\nSnopes has a good [article](_URL_2_) on this. Most of what I know jives with their take.\n\n[This](_URL_1_) is also a very good article on the overall subject. You can see how inconsistent some of the dollar amounts and who owes who what. I'm not even sure Jackson himself or his lawyers could really explain it.\n\nThat being said, he had bought into other artists' catalogs as well on the advice of (strangely enough) Paul McCartney. What they are in particular and how much they have been worth to him is largely unknown."
]
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"http://www.time.com/time/arts/article/0,8599,1908185,00.html",
"http://www.pophistorydig.com/?tag=michael-jackson%E2%80%99s-music-catalog",
"http://www.snopes.com/music/artists/jackson.asp"
]
] |
||
1ho7bc | why doesn't the radio work when you start the engine? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1ho7bc/eli5_why_doesnt_the_radio_work_when_you_start_the/ | {
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"text": [
"The starter motor sucks up a great deal of current as it starts the engine. There isn't really any electricity to spare for the radio while the starter motor is drawing current.",
"Several circuits on key ignition. Crank diverts all power to starter and coil or coil packs, so engine has the best chance to start."
]
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[],
[]
] |
||
cay1tq | why do cars take longer to start when in cold weather vs warm weather? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/cay1tq/eli5_why_do_cars_take_longer_to_start_when_in/ | {
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"text": [
"Gasoline burns when it's a mixture of gasoline vapor and air. When it's cold it is harder to evaporate it",
"The engine also needs to be lubricated by the engine oil to function correctly. Colder oil is more viscous i.e. it doesn't flow as easily. With the oil being a lot thicker at lower temperatures this means there is more resistance inside the engine and that makes it harder to start."
]
} | [] | [] | [
[],
[]
] |
||
4unbjn | what is the "halting problem" in relation to something being turing complete? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4unbjn/eli5_what_is_the_halting_problem_in_relation_to/ | {
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"text": [
"Halting problem means that\n\nIt's impossible to make a program that sees if another program runs indefinitely\n\nFor example this pseudo code would run forever\n\n 10 X = 0\n 20 PRINT \"Hello world\"\n 30 X = X + 1\n 40 IF X > 0 GO TO LINE 20\n\nX will never get 0 or under and so the code will run forever. This is easy for humans to see but not for computers.\n\n"
]
} | [] | [] | [
[]
] |
||
25h8t0 | stack (programming) | What is a stack in programming, I haven't come across this in my own programming but have elsewhere. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/25h8t0/eli5stack_programming/ | {
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"A stack is a data structure. Like a stack of plates, the last plate you put on the stack is the first one you take off. This is known as LIFO, last in first out. A stack is useful if you are working on a task A and get interrupted by task B. You put A on the stack and start to work on B. When you're done with B, you check the stack to see what the previous task was. If C interrupts B, you put B on the stack, and start work on C.",
"A stack can be taken quite literally. Say you have a stack of papers (an organised pile, one on top of another). You can put another paper on top of the original stack (push) or take one of the top (pop). However never from the bottom or middle, as the stack would 'collapse' (Last In, First Out principle). \n\nThis same goes for programming. You can make a stack hold data (it's a data structure) to analyse (like strings, integers etc.) or you can view it like in this Simple Stack Machine. (_URL_1_).\nBasically all your instructions are put on a stack to manipulate.\n\n\nExample:\n\n LDC 2\n LDC 3\n ADD\n\nThis puts (pops) '2' on the stack, then '3'. The 'ADD' command takes (pops) the two from the top (or in this case read it from the bottom to the top) and adds them to return (push) the result on top of the stack.\n\n~~I'm not a 100% sure about this, but whenever you encounter a stack overflow, it just means there are too many 'commands' on the stack, since a program is given a maximum size (the stack of papers can't get higher than the roof).~~\n/u/lobsang_ludd corrected me here. Stack overflow actually means that the *call stack* is too big.\n\n[Lobsang_ludd](_URL_0_) on call stack:\n > This is a stack that is generally automatically maintained to support procedures calling other procedures - when this happens we need to remember who called us and how to resume that procedure once we're done, so we bundle up the state (variables etc.) of the calling procedure along with the point in memory we should resume from and place it on the call stack. When a procedure returns, it pops off the top element of the call stack so the computer knows what should happen next. \n\nEdit: formatting\n\nEdit #2: Added a small correction which was commented on [below](_URL_0_).",
"Ask this on stackoverflow",
"A stack is a data structure. It's not a difficult concept to grasp. Imagine you are washing dishes and you are stacking plates that you wash. After you wash one, you put it on the stack. After you wash the next, you put it on the top of the stack. You don't put it in the middle or on the bottom. Now when you want to grab a plate to put some food on, you grab the plate at the top. Again, you don't want to take the plate from the bottom. \n\nThis concept is called last in, first out (LIFO), or first in, last out (FILO), depending on the person. In other words, the last item you put on the stack (\"push\" onto the stack) will be the first item you take off the stack (\"pop\" from the stack).\n\nStacks can be used for anything. In it's most basic form, it is simply a way to hold a collection of data, just like an array or a linked list.\n\nHowever, there is a very important use of a stack that you see in programming. This is the memory stack. It is hardware based - not software based When you here the term \"the stack\", this is what is being referred to. The actual stack data type is rarely used in software development, but *the* stack is very important.\n\nBasically, the stack is a region in main memory that is used to store temporary values during execution of a program. Simplistically, the stack is a huge block of memory in RAM. As a program runs, it will push and pop values to and from the stack as necessary. \n\nIt's use is pretty simple. If a function creates a new variable, the value for the new variable is stored at the top of the stack. When a function exits (or when the compiler removes deletes the variable for memory management purposes), all the variables created by that function are taken off the stack. If a function is called in another function, the variables are continually added to the top of the stack as needed. \n\nSo whenever you create a variable in a programming language, it is stored on the stack somewhere. They are stored in the LIFO order. If you create a new variable, it is put at the top of the stack. This variable will then have to be removed before you remove any variables below it. It is simple really.\n\nAnother interesting concept here is stack overflow. You have probably seen this term come up frequently and you may not know what it means. The stack is a limited region of memory. If you use up all of the stack, then you can't add anything else to the stack. This is a stack overflow. Basically, it is using up all your memory. Being the rebel I am, I used to cause stack overflows all the time on my calculator by doing calculations with crazy high numbers. What I was doing here was causing my calculator to continually enter functions and continually make new variables until it ran out of space on the stack (the calculator obviously would have limited RAM compared to a desktop).",
"Have you ever found yourself in a situation where you have to do a complex task that has many subtasks, and then each of those subtasks also has subtasks?\n\nOne example (which may only be familiar to us older people) is doing your taxes on paper. To fill in some boxes in the tax forms, you have to go off and fill out a different form to calculate the number that goes in the original; the IRS normally calls this a **worksheet*. And to fill the worksheet, you may also need to go and do something complicated as well, like find a bunch of different financial records, figure out which are relevant to the worksheet, and so on.\n\nWell, executing a computer program is more or less like this, except more complicated. There are more steps, and the hierarchy of parent tasks to subtasks can get much deeper. When you're doing your taxes you rarely have more than three levels of subtasks, but when executing a computer program you can easily have a subtask that is a thousand levels deep.\n\nStacks are a data structure that manages this sort of task/subtask situation. The idea is that when, in the middle of a task, you need to perform a subtask, what you do is you \"push\" into a stack your unfinished work on the current task, and start the subtask. When you are done with that subtask, you then \"pop\" the item at the top of the stack, and you're back to where you were before starting the subtask.\n\nMany algorithms in computer science have this task/subtask flavor, so stacks are a very common data structure. Also, the way computer programs keep track of what they're doing is by maintaining a stack (called \"**the** stack\" by programmers) of what function has called which other one and is waiting for its results. When a computer program encounters an error, many languages will print a representation of the state of the stack when the error happened, which allows the programmer to see in which line of the program it was, and how the program ended up executing that line.",
"Just for knowledge sake, there is also a queue in structs. It is like a line at a cafeteria, first in line first out, the opposite of a stack. "
]
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"http://www.reddit.com/r/explainlikeimfive/comments/25h8t0/eli5stack_programming/chh6elz",
"http://www.staff.science.uu.nl/~dijks106/SSM/userinterface.html"
],
[],
[],
[],
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|
bta8ce | how does anything live on islands where the max elevation is less than about 20 feet? | Every time I see videos of boats hitting massive waves that they have to climb like a small mountain it makes me wonder how these same storms don't just wipe clean any and every small island in the ocean. It seems like whenever a big storm came, waves would just wash over any low lying islands in their path and take everything with them into the oceans. Yet you still see palm trees and sometimes even people and animals living on tiny islands. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/bta8ce/eli5_how_does_anything_live_on_islands_where_the/ | {
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"text": [
"The same waves typically peter out as the sea floor elevation rises towards the island.\n\nWhile it does happen, the waves produced out at sea dont carry the same force as a tidal wave, as only the surface water is raised (vs a tsunami in which the entire depth of the ocean is raised)",
"Well, let's start by looking at a wave. From the surface a wave kind of looks like a 'hill' of water moving forward. It's a little more accurate to think of a wave as a wheel of energy rolling through the water. Half of this energy wheel is above sea level, half is below it.\n\nThe water itself stays in place but where this wheel of energy passes, the rolling of the wheel pushes the water up. Kinda like moving your finger underneath a blanket, the blanket doesn't move but as you move your finger, different sections of the blanket get pushed up.\n\nIf you're ever in the swimming pool, you can replicate it with your hand. Just hold your hand vertically under the water, palm forward. When you push, your hand will displace the water causing a wave to rise. The water sinks right back down behind your hand but wherever you push your hand, the wave will go.\n\nNow those ships climbing mountainous waves are usually in the open ocean in deep water. When storm winds push the water, massive waves are created.\n\nIslands, on the other hand, don't float in deep water like a boat. You can think of them more like hills on the continental shelves or the peaks of underwater mountains. Water near an island is shallow and gradually gets deeper until it drops off into the depths.\n\nThat means that when that energy wheel approaches an island, there is gradually less and less water for it to push around. On top of that, many islands are surrounded by reefs and rocky formations that break up a wave before it reaches the shore. \n\nThat doesn't mean that waves can never bother an island. Some tiny islands really are frequently washed over when there's a storm. Others are protected by reefs or have high points where animals can seek refuge. And truly massive amounts of force like seafloor earthquakes can create tsunamis that are almost unstoppable.\n\nThe biggest danger for really low lying land is an overall rise in sea level. Waves is just water that rises *above* sea level. There are many ways of dealing with waves. But if the sea level itself simply rises above a low lying island, that's a whole different story."
]
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[],
[]
] |
|
fx31w0 | why does turning the music down in the car help you better find a parking spot | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/fx31w0/eli5_why_does_turning_the_music_down_in_the_car/ | {
"a_id": [
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"text": [
"Fewer senses are being overwhelmed. With lower volume you are focusing solely on seeing now.",
"Your brain finds it easier to process sounds so prioritises them.\n\nWhen you turn the music down it's got less work to do"
]
} | [] | [] | [
[],
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] |
||
16i9uc | the (arbitrary) difference between species and subspecies? | Having spent some time watching and reading in the various atheism-related threads in the last 1,5 years since I'm a redditor, I wondered about some of the specifics about the difference between micro- and macro-evolution. I see many creationists who claim that while micro-evolution is a fact (we see the evolution of antibiotic-resistance bacteria, etc.), macro-evolution is not, since we have no 'evidence.' From what I understand, the difference between a subspecies (or breed) and species seems arbitrary. I.e.: while the differences in various breeds of domesticated dogs is seen as variation within the species (thus creating different subspecies, or an example of micro-evolution), we classify wolves as a separate species from dogs (hence, the evolution of domesticated wolves to the present dog would be macro-evolution). What I would like someone to explain to me like I'm five is: how is it decided that the variation within a species has become large enough to classify an animal as a different species altogether? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/16i9uc/eli5_the_arbitrary_difference_between_species_and/ | {
"a_id": [
"c7wa5fq"
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"text": [
" > how is it decided that the variation within a species has become large enough to classify an animal as a different species altogether?\n\nWhen someone feels it is, but one of the criteria they're supposed to use is that the two groups can't (or don't) regularly interbreed. This usually is a good signal that substantial differences have developed in the gene pools."
]
} | [] | [] | [
[]
] |
|
di6fhd | why does it look like time goes one second backwards when you look at an analog watch? | I've always wondered why I feel like I see the needle go one second backwards or stand still the moment I look at a watch | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/di6fhd/eli5_why_does_it_look_like_time_goes_one_second/ | {
"a_id": [
"f3tm675"
],
"score": [
18
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"text": [
"The short version is your eyes are moving faster than your brain can deal with it, and you're experiencing lag. While your eyes are trying to focus on the new target (the watch), your brain isn't able to interpret the images for a short time. Once it \"catches up,\" the brain realizes it has a gap in its memory, so it takes the first new image that it *can* process, and copy/pastes it over the gap.\n\nSo if you look at your watch at 25.5 seconds, and your brain doesn't catch up until 26.0 seconds, it takes the image of 26.0 seconds and pastes it over the .5 seconds it took for the lag to go away. So you *think* that you're seeing 26.0 seconds for 1.5 seconds...you were actually looking at the watch while it said 25, but you don't remember it.\n\n_URL_0_"
]
} | [] | [] | [
[
"https://en.wikipedia.org/wiki/Chronostasis"
]
] |
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