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6ejzml | why is hockey the only sport where fighting is socially acceptable/minimal penalty is given for fighting. Was this always the case? | Repost | explainlikeimfive | {
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"Hockey is a sport that is really built into people getting physical with each other. Lots of swinging weapons and sliding into each other is a natural part of the game, so people get physical a lot which goes from accidental slamming to intentional checking to just punching each other pretty easy. The penalties are low because the sport started pretty unregulated and no one cared so when the game got bigger it was already just a part of the game and it rarely leads to real injury and people love it so no one wants to get rid of it that bad."
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6f1309 | What would happen to light inside of a box with a mirror-wall interior? | Repost | explainlikeimfive | {
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"Assuming that the hypothetical box is completely and perfectly enclosed with no way for the light to escape, the light would infinitely reflect within the box while gradually losing energy until it dissipates. Meanwhile the box will become warm (hot, maybe?) because the light energy is converted into heat energy every time the photons impact and reflect off of the mirrored interior of the box until they eventually lose all their energy and disappear."
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6f1aa4 | What is the difference between Britain and England, and what is the country currently called? | Repost | explainlikeimfive | {
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"The United Kingdom (UK) - A sovereign state made up of parts of two islands (the British Isles) England, Scotland, Wales, Northern Ireland - The 4 nations that make up the United Kingdom Great Britain - The larger of the two British Isles. Contains England, Scotland and Wales Ireland - The smaller of the two British Isles. Contains Northern Ireland and the Republic of Ireland",
"URL_0 The Difference Between The United Kingdom, Great Britain, England And A Whole Lot More",
"Britain is one of the names of the Empire based on the British Isles. It is officially The United Kingdom (short name). England is one of the kingdoms that is a part of the UK. It is the nation that holds Parliament and where the Queen lives. The other kingdoms of the UK are Scotland, Wales, and Northern Ireland, and there are numerous holdings around the world that are Crown Dependencies and overseas territories. There are also entire modern nations that are subjects to the Queen and therefore subjects of her empire but who are not a part of the UK (Canada, Australia, New Zealand). So things can be complex.",
"Deleted and reposting because I can do it better. The current country is called \"the United Kingdom of Great Britain and Northern Ireland\". Some people call it the UK for short, some people call it Britain for short, which is fine but not technically correct. There are four countries that unite to form the UK. Each one used to be independent (or part of another country) before they united. Those four countries are England, Scotland, Wales, and Northern Ireland. The geographic island which is made up out of the lands of England, Scotland, and Wales is called \"Great Britain\" or Britain for short. Northern Ireland is not on that island. It's on another island to the west of it called Ireland. Most of Ireland is its own independent country (the Republic of Ireland) but one bit is still part of the UK and that bit is called Northern Ireland."
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6f1ffq | Why did Nixon resign? | Repost | explainlikeimfive | {
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"Nixon resigned because the House was about to vote to impeach him for obstructing justice in the Watergate investigation. Nixon had his key advisers hire some guys to break into the opposing political party's headquarters and steal their things and then tried to cover it up. Because his role in the cover-up was being exposed, he resigned to avoid being removed from office.",
"Nixon was about to be impeached (put on trial for misconduct) for obstructing justice in the Watergate investigation and for illegal wiretapping. There was more than enough evidence for this impeachment to result in him being removed from office by force. Resigning before the impeachment was his way of saving some small fraction of honor for himself and the country and simply saved a long drawn out impeachment process of being done. He was open to face criminal charges for his actions either way but by stepping down before impeachment he was also put in a place where his successor could pardon any possible crimes that he had committed. Impeachment is one of the few things that the President does not have the authority to pardon and while it has not been legally tested it is fair to assume that criminal charges filed as a result of impeachment would equally be immune to being pardoned. So it is possible that by resigning he was 1) Removing the need and option of the Supreme Court ruling on if crimes discovered in the trial process of impeachment are immune to pardons. 2) Was a deal with his successor to get a pardon, which he did.",
"To avoid the impending impeachment proceedings against him. The Nixon administration employed numerous shady and oft outright illegal methods to help secure his re-election, including but not limited to harassment of activist groups that supported opponents using the FBI, CIA and IRS; bugging and wiretapping political opponents, and having some underlings break into the Democratic headquarters at the Watergate complex, which is where the scandal comes from. Thing is, that last bunch got caught and arrested. The press was originally told that these were Cuban Freedom Fighters (the early 70s equivalent of \"it's terrorists\"). These were very different days, however, and the government actually began to investigate, despite orders to the contrary from the top. The money got followed, and it quickly was unearthed that large cashier's checks (25k; that's about 150 000 each in today's values) from the Nixon Re-Election campaign were given to ex CIA and FBI men loyal to the party; notably one of the burglars arrested... As the money continued to be followed it wormed its way to the top; these had been cleared through the Republican party and the CRP, and meanwhile the white-house \"inexplicably\" was moving to distance itself from these men it was \"completely unrelated\" to. Luckily however, Nixon had a tendency to tape *everything* in his office all the time.... Of course just before those were leaked (today that would be 'treason') congress - which had a spine at the time - was in full hearings on the subject, with Special Prosecutor Archibald Cox immediately subpoenaing the tapes. Nixon claimed executive privilege and ordered Cox to drop the investigation. Cox refused of course. This led to the \"saturday night massacre\": Nixon ordered the Attorney General to fire Cox. The AG refused to perform such a dirty act and resigned, thus Nixon passed on the order to the next in line, the Deputy AG, who also resigned in refusal. This continued all the way to the Solicitor General, who agreed and fired Cox. This was the moment when, questioned about it, Nixon made his famous line; \"I am not a crook\". At this point Nixon was secretly indicted as a co-conspirator to the seven men who had helped act in the crimes and coverup (out of a total of 48 found guilty by the end of things) to a Grand Jury. Nixon released small portions of his transcripts as per the subpoenas, with \"profanity\" and \"anything that could be related to national security\" edited out. Again, not as bad as entire documents blacked out as done today, but while it originally gave him a good image to do so, reading the documents left people feeling quite 'unclean'. Then the tapes were brought out, with conversations about how to cover things up right there in the open, except for certain long portions of what was likely far more incriminating stuff \"accidentally\" deleted here and there. \"accidentally\" of course. With the final investigations closing in and impeachment proceedings on the verge of officially commencing, Nixon resigned officially."
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6f2vrp | What would happen if you wake someone up if they're sleepwalking? Can it harm them or is it a myth? | Repost | explainlikeimfive | {
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"I think the bigger danger is that they could harm you. Someone who is sleepwalking is not consciously controlling their actions, and depending on what they are dreaming about they may interpret an attempt by you to wake them up as an attack and respond in kind. I suppose they could also injure themselves in a similar manner, bit that seems less likely to me."
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6f4e63 | How do we know how far certain stars are from us even though they are far beyond our reach? | Repost | explainlikeimfive | {
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"One method for nearby stars is called \"parallax\", and it's basically just how it moves relative to other stars while Earth is moving around the Sun. This gives rise to a unit of distance you may have heard - the parsec. This is the distance corresponding to a parallax angle of 1 arcsecond (1/3600th of a degree) per year, and is a bit over 3 light years long. For farther stars, a different method is used based on what kind of light comes from certain types of ordinary stars and supernovas called \"standard candles.\" Since we know how these stars work, we know what kind of light to expect from them, and can thus use what we actually receive as an indication of how far away they are based on how dim the light is. This latter method is statistical rather than exact, because there are a number of complicating factors, but astronomers can establish upper and lower limits on the distance using that and other factors (e.g., comparing to other stars around it that have likewise been calculated). The short answer is that for most stars, we *don't* know how far they are for certain, we just have reasonable theories."
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6f58ay | How does Walmart know what I've bought in store? | Repost | explainlikeimfive | {
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"If she used a credit card or a debit card your name is on those accounts and they know who you are. So if she bought with cash this is creepy, but all other payment methods has a link to her account in some manner."
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6f654c | why do humans brush their teeth even tho no other animal does it. | Repost | explainlikeimfive | {
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"We're one of the few animals to eat a high-carbohydrate diet, a diet only possible because we grow grains as crops with agriculture. Because we eat carbs, we leave lots of delicious bits of sugar behind on our teeth for bacteria to feast on, causing tooth decay. If we don't brush, we can get painful cavities and our teeth can fall out. This is a huge health problem, and was even worse before modern oral hygiene practices. Domestic dogs that eat corn-based dog food also need to have their teeth cleaned, which wild dogs don't need. Luckily there's chewy dog treats you can give your dog that do a decent job at cleaning their teeth so you don't have to do the unpleasant task of literally brushing your dog's teeth with a toothbrush.",
"Our diet is rich in sugars, which bacteria love, because most our foods contain complex carbohydrates: think wheat, potatoes, fruit. Our food simply leaves a buffet for bacteria to feast on behind in our mouths. Second: we learn. We've discovered that certain foods do this more than others, and we've learned that fluoride helps counter this effect. That means brushing alone is already neat (the calcium (chalk!) in the paste scrapes away most of that buffet), and that brushing with fluoride actually counters most of the effects! How we've discovered fluoride does this: we observed that over the span of decades, some towns' people suffered tooth decay less than others, and we looked and found that their water supplies contained more fluoride. Off to the lab to check if fluoride indeed does this, and yup: it does. Voilà, fluoride based toothpaste became a thing. Add SLS to make it bubbly through friction, so that the bubbles can get the fluoride more between your teeth; add mint to make it nice and fresh; and bam: modern toothpaste for you.",
"While a high-sugar diet that everyone else talked about is the main reason, we're also the only animals to shave, wipe our butts, wash our hair and use deodorant. It's kind of just another part of hygiene in human society to have clean teeth and breath that doesn't stink.",
"Lots of answers, but mainly: because we can. Other animals have terrible teeth and terrible breath. We like to take care of ours, because we live a long time and need them.",
"Other animals don't brush their teeth but there are several that have other animals clean their teeth. Sharks have little fish, crocodiles, hippos have small birds and there's probably other teeth cleaning relationships.",
"I have a number of dogs. Those that chew sticks have clean teeth while this that don't need dental care at the vet. I'm thinking that stick chewing is an evolutionary adaptation to maintain oral health.",
"Human diet is normally rich in sugar, and animals and even the people of Pompeii before the eruption have been found to have good teeth and no cavities. And correct me if I'm wrong, but i believe the people of Pompeii used honey to sweeten their food instead of sugar. But then, sugar isnt the only thing that effects teeth, sodas, do aswell. So i believe its carbohydrates that effect teeth and there wasnt much of that for probably, 90-95% of recorded history."
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6f9u0a | Why is it when on a slow internet connection ads on youtube do not have to buffer at all and play in high definition, but when the video starts, it has to buffer even on the lowest quality setting? | Repost | explainlikeimfive | {
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"YouTube videos end up fitting into two categories: a small number of videos that get watched A LOT, and a large number of videos that only get watched sometimes. Videos in the second category are stored on YouTube's big ol' server setup, but videos in the first (the popular ones) are cached on boxes at ISPs around the planet. This makes retrieving those videos MUCH quicker. Know what's also on those boxes? The ads! Because ads are also almost always regional (specific to your country and language). So if you watch a youtube clip that came from the big archive, it's able to pull an ad immediately from the local cache then has to do more work to get the one that's stored on the big archive."
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6faxes | Why are some penises curved while others are straight and does any external factor, like underwear, affect it? | Repost | explainlikeimfive | {
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"From a previous post: There are 2 'tubes' that fill up with blood when it become erect. If one of them is shorter then the other that can cause it to be curved. Edit: Just to let everyone know. I'm not a doctor or anything. I just knew that fact from some weird youtue loop I got stuck in watching British Sex Education shows."
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6fb9d6 | why do babies have a distinct baby smell? What causes it? | Repost | explainlikeimfive | {
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"You're probably referring to baby powder. It's not natural, you have to apply it. But it's pretty widely used, and the kind without talcum still smells the same. A lot of other baby products - Johnson's baby wash, for example - has the same scent. Left to their own devices, babies smell like shit and vomit."
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6fbndb | How do space stations and satellites manage to not collide with space junk? | Repost | explainlikeimfive | {
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"Every single piece of stuff up there bigger than a screw is tracked, seriously! It really is. But space is BIG, truly unimaginably big. So we know where the stuff is flying around, so we just use all that other big empty space so that they don't collide"
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6fh9s6 | How is light a wave AND a particle? | Repost | explainlikeimfive | {
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"It isn't really. Light is something that sometimes behaves in way that is best described as a wave and sometimes in a wave that is best described as a particle. Light is neither of both, it is ... *light*. We don't know exactly what it is apart from that. But we know that we can make quite accurate science with it when we treat it like a wave in those situations where it behaves like a wave and treat it like a particle in those cases when it behaves like a particle. For the record, everything in the universe is that way. Also electrons sometimes behave like waves. Even really big molecules sometimes behave like waves.",
"Welcome to quantum mechanics! I believe the unfortunate answer to your question is: we don't know. But if you can explain it, proceed to GO and collect your $200 (or Nobel Prize). While we don't know HOW it is, we can demonstrate light having both properties via the [double-slit experiment]( URL_0 ).",
"Unfortunely it sorta isn't. The full (very, very complex) answer comes from QED (quantum electrodynamics). Which (basically) says that \"excitations\" in a certain fields result in a certain phenomena. A 'photon' is essentially just an excitation in the (electromagnetic) field (this means radio, microwaves, visible light, electricity and magnetism, are -mostly- all the same thing). The idea that a field excitation is both a \"particle\" and \"wave\" comes from the weird way these fields work. The answer is --long. Sufficient to say, \"photon\" is just shorthand for a particular excitations. And \"light wave\" is another. But, really they're not categorical different enough to say they can \"be\" anything --and certainly not at the same time."
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6fhq8s | Why do people believe they can feel when a storm is coming indicated by pain or discomfort from recent/old surgeries, injuries, etc.? | Repost | explainlikeimfive | {
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"Things like air pressure or humidity can affect injuries, past surgeries, ect. and cause pain, discomfort, or some other feeling. Changing in air pressure or humidity tend to signal changes in weather."
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6fjo8q | Why are most radio stations in the 90, 90.5, 91.5, etc | Repost | explainlikeimfive | {
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"because the fm spectrum is 87.8 MHz to 108.0 MHz, for a total of 20.2 MHz. It is divided into 101 channels, each 0.2 MHz wide. so a radio station thats 90.5 is actually 90.4 to 90.6, so just tune to the center at 90.5 for the best signal."
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6fjuep | what is the point of keeping the penny around if it costs more than a penny to produce it? | Repost | explainlikeimfive | {
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"There is not a point to keeping it around (in my opinion), but it really depends on the person. I highly reccomend [CGP grey]( URL_0 ) He makes some REALLY great videos on why we should remove the penny from circulation, and just really interesting stuff in general (like the theory beyond completely stopping traffic jams)"
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6fl1ma | why movies generally shoot at 24 fps, but video games generally go for 60 or higher fps for the most cinematic experience? | Repost | explainlikeimfive | {
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"Mainly because of motion blur. When your videogame creates the video, each frame is generated separately, and is a completely static image - you can take a screenshot and it will not appear as if it was a part of a video. When you shoot a movie, each image is exposed for a non-negligible amount of time, such as 1/60 or 1/100 of a second. During this time, motion is captured in the image, resulting in a small blur. This contributes to making the video appear more smooth. [This video]( URL_0 ) shows the difference between high shutter speed (= no motion blur) and low shutter speed (= motion blur).",
"Movies are shot, games are rendered When an object is moving in a movie each frame will have blurring showing the direction of the motion. This is because the object is able to move across the film/sensor while the lens is open during each frame. This blurring is similar to what your eye would see while watching a moving object, and when shown at 24 fps it is close enough When an object is moving in a video game it is often rendered as a series of crisp images so you need them coming in faster to create the correct blurring effect in the eye. Without the blurring it acquires the odd effect that stop motion movies have where it looks kinda smooth but you *know* its not smooth",
"24Hz is the lowest you can go before humans notice the flickering. So this is how you get the longest movie on the shortest film roll. If you see old films they might be lower frequency, as low as 10Hz at which point the flickering is very noticeable and tiring. But even at 24Hz you may notice the stuttering images even if they are not flickering. To fix this on digital images there is interlacing which allows you to double the frame rate without increasing the bandwidth. This is why things shot with a TV camera looks better on a TV then things shot with a film camera and then scanned to TV format. It is also popular for TVs to double the frame rate again by interpolating the intermediate frames. So for TV it is not unusual to have 100Hz. The movie industry is not as keen on jumping on to higher frame rates and rather value higher resolution. But you do get some 48Hz movie systems. For example the Hobbit was shot in 48 frames per second."
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6fpu0n | Why does a tilt-shift lens make subjects look miniature? | Repost | explainlikeimfive | {
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"Classic [view cameras]( URL_1 ) have the ability to not only move the lens in and out for focusing purposes, but to tilt and shift both the lens and the film plane. This gives you the ability to adjust for perspective distortion and have variable focus fields in ways that an ordinary camera could never come close to producing. As one example, an ordinary camera has a focus plane which means that there's a plane in space in front of and perpendicular to the the camera's line of sight where everything is in focus, and anything nearer or farther than that plane will be progressively out of focus. A view camera, on the other hand, lets you change that plane so it's no longer perpendicular to the line of sight. So imagine you're photographing a scene where there's something to the left and near you, and something to the right and far away. A view camera would allow you to put both of those objects into focus. There's a [gallery on flickr]( URL_2 ) that contains some beautiful tilt-shift images. ---- Now a view camera can also be used to create the opposite effect. You could use the tilt-shift features to create an extremely restricted range of focus. By coincidence, when you use a normal camera to photograph miniatures, the camera will also have an extremely limited range of focus. Photographs of miniatures very often have the foreground and background out of focus whereas a photograph of an actual landscape would have everything in focus. Our eyes and brains have seen enough photographs of miniatures that we've learned to associate the limited range of focus with looking at miniatures. So now, when we look at a landscape that was photographed with the above-mentioned tilt-shift effect, it makes us think we're looking at a photograph of a miniature. It also helps a lot to shoot the scene from above, as a miniature would be photographed. ---- Finally, we come to the computer \"tilt-shift\" effect. This is nothing more than drawing a line through the scene (typically parallel to the horizon) and having the computer blur the scene progressively away from that line. And if the scene is animated, you can do other things to make it look like a miniature, such as speeding up the time frame or making the animation a little jerky so it looks like it was generated with stop-motion animation. There's [a video]( URL_0 ) that demonstrates this wonderfully.",
"You, whether you realize it or not, experience something called \"depth of field\" in your vision. When you are focused on something close up, things that are far away are blurry. When you focus on something far away, near-by things are blurry. Now there's a lot mechanics, purely optical mechanics, as to why and how this depth-of-field works. Explaining all of them would take several hours and a larger character count than I have here. But basically the amount of \"in focus stuff\" is a percentage of how far away from the lens (camera or eye) the thing being seen happens to be, and the narrower the opening around the lens' center, the higher the percentage. So pin-hole cameras can seen nearly 100 percent of the depth, and that's how you can get a cheap disposable camera that you don't have to focus at all. So anyway, if you look at something very close (or take it's picture), you'll notice that the things that are even closer or just a touch further away are blurry. But if you look at a distant tree you'll see that the whole forest is in focus. So go back to that percentage thing. Pulling numbers out of my arse, say I've got ten percent depth of field. If I look at something ten inches away I'll be able to clearly see the things ten inches away, and a half-inch closer than that, and a half inch further than that (because 1 inch is ten percent of ten inches.) but something one in closer or further away (e.g. at nine inches, or eleven inches) are outside that one-inch-thick \"10% depth of field\". If I look with the same optics ratios (lens opening width etc) at something ten miles away I get the same 10% depth of field so I get to see everything from 9.5 to 10.5 miles away as \"in focus\", but something \"only 9 miles away\" or something \"over eleven miles away\" will be blurry. The further out of the focal lenghth, the more blurry things are. So at 20% its really blurry and at 40% it's so out of focus that your brain just doesn't even bother with it unless you move your eye and re-focus. Now we add a feature. Our eyes constrict the opening around the lens when there is more light. The higher the light levels the smaller the opening. The smaller the opening the larger the depth of field. This is why, on a bright and sunny day, the whole world just feels sharper and more in focus. More of it _is_ factually in focus, you can literally see more of it well at each moment. As an added bonus you have binocular vision. You can tell how far something is from your face by how much your eyes have to cross to see it. If you'd never seen a picture of a landscape before you might be a little confused as your brain would say \"deep\" by being able to see it all at once, but your cross-eyed-ness would say \"close\". It's not a huge effect and you know about models, so it's easy to say \"photograph\". That is your brain knows about dolls and miniatures and stuff like that so it can cope with the \"confusion\". So back to tilt and shift... I show you a tilt-and-shift image of say a town. There's a guy in the center of an intersection. He's in focus, but the buildings right above and below him are not in focus. 1. Your brain knows from the binocular vision that the whole picture is close to you. 2. Your brain knows that the lights are good and your irises are constricted so it should have XXX depth of field, so lets say 20% just for example. So the blurry buildings must be at least 10% closer in the \"near\" part (lower building) and 10% further away in the \"far\" part (higher in the frame building). And if the next most blurry thing is really even more blurry it must be even further out of the depth of field. So your brain does some organic math. Using \"one guy\" (the thing that's in focus) as an estimating tool, it guesses \"how many guys\" it would take to get from the in-focus guy to the blurry buildings. In a normal picture of a guy far away, e.g. the picture before the tilt-and-shift effect was applied, the nearest blurry building might be a hundred or a thousand guys away from the guy. In the effected picture it's only eight or ten guy away (or whatever). So if you get to see a hundred or a thousand \"guy's worth of depth\" the guy is big and far away, for the same reason that one tree ten miles away lets you see from 9.5 to 10.5 miles clearly and that's a whole forest of trees. But if only get to see like six \"guy's worth of depth\" then the guy must be very close and very small like how looking at a model of a tree ten inches away only lets you clearly see from 9.5 inches to 10.5 inches. So the more narrow the in-focus area is the closer to your face and the smaller the objects \"must be\" for the percentages to work \"in the camera\", whether that camera is a real camera, a photoshop image, or your actual eyeball. Finally the other part of the tilt and shift (I don't remember which part is which, but I think this is the \"shift\" part) is that the line of what is \"in focus\" is usually shifted from the apparent horizon. So the in-focus band isn't square to the image. This gives a disassociated feeling, as the the thing being looked at is unreal, as in a model, being looked at from an angle. We live most of our lives \"square to our chess board\" when we are involved, when things are \"Real\". But when we look at a diorama we can look in-and-down at interesting angles and such. So by adding that angle to to the in-focus band the effects artist has given our brains permission to consider that the scene is in some way artificial. So that gives us permission to call the image \"fake\". In the end \"fake\", \"close\", and \"tiny\" signals are all provided very, strongly. So much so that \"real\" and \"full size\" are \"impossible\". So our brain \"knows\" it's a tiny, tiny model captured from very, very close up at a slightly cock-eyed angle."
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6fqab6 | What is wind | What cuases wind to happen? | Repost | explainlikeimfive | {
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"dik5idd"
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"One amount of air gets hotter than another. Hot air expands. This expanding hot air moves, causing wind. Evaporation of water moves heat from the surface to the air. This, and sunlight causes air to heat, causing wind. Edit: u/cedarbabe is right about it being about pressure, not hot air's expansion."
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6fra16 | Why is 'good night' a farewell phrase but all the other times of day (morning, afternoon, evening) are greetings? | Repost | explainlikeimfive | {
"a_id": [
"dikfjbs"
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"text": [
"I had this explained to me during my second year of German class. In English we say \"good night\" to end the night like you said, with all other similar phrases being greetings. In German we have; \"Guten morgen.\" (good morning), \"Guten Tag.\" (good day), \"Gute Nachmittag.\" (good afternoon), \"Guten Abend.\" (good evening), and \"Gute Nacht.\" (good night). The last two are used around the same time. However using \"Abend\" is either a greeting if meeting around dusk and onward or a parting phrase if leaving in the evening. Using \"Nacht\" signifies you are going to sleep upon your departure or reciprocating someone's departing statement of \"Gute Nacht.\" In my opinion it is just a culture thing that has to do with how our language is set up. I don't know about any other languages though."
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6fravo | Why does a video of a spinning object suddenly make it seem like the object stops spinning and then continues in the other direction? (i.e. A video of a cars wheels) | Repost | explainlikeimfive | {
"a_id": [
"dike6c4"
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"text": [
"Imagine a wheel has six spokes. That makes sixty degrees of rotation between spokes. Videos aren't actually motion, but sequential pictures that when strung together fast enough blend together to appear like motion. So let's say the wheel is moving one degree per frame. It will look like it's moving one degree per frame, because it is. If the wheel moves two degrees per frame, it will look like it's moving two degrees per frame. But there are sixty degrees from one spoke to the other, so if the wheel moves sixty degrees each frame then it will look identical to the previous frame, as if it hasn't moved at all. And if the wheel moves fifty-nine degrees in a frame, it will look like it's moving one degree backwards instead. This is because we don't see the motion. We just see two pictures and make the most logical connection from each picture to picture."
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6ftint | Before proper dental hygiene how did people eat without constant pain in their teeth? | Repost | explainlikeimfive | {
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"They didn't. Most diets before the industrial revolution were fairly free of sugars, so they had that going for them. But the complete lack of dental hygiene meant that their teeth could, and did, rot quickly. Places like Egypt actually show a lot of this -- many bodies show significant enamel erosion since much of their food was laced with sand (unavoidable) and this accelerated the decay of their teeth. Next time you're at your dentist, thank them for their work.",
"Great question and I just wanted to share a story of how some current people without proper hygiene eat without pain... I work with a group that provides oral outreach to orphans and children in Malawi, Africa and South America. We go into some of the world's most remote villages and bring toothbrushes and toothpaste, along with dentists and hygienists who volunteer from the States. The majority of the people we visit have never owned oral hygiene products and line up for miles and miles just to get a travel-size toothbrush and toothpaste. During my first trip, I expected everyone's teeth to be decayed and rotted, but many, surprisingly, actually had great oral hygiene. This was most apparent in villages with sugar cane because the phytates attack the bacteria. They suck the juice out and then chew on the stalk and it's very effective. They also maintain decent oral hygiene because their diets are natural and not full of process foods and sugars, etc (the sugar cane is raw). With that being said, we certainly see many horrific cases and it breaks my heart because I can't imagine the pain and suffering some endure with mouth decay and rotted teeth. Some of their necks will swell the size of a grapefruit or larger! Malawi’s HIV prevalence is one of the highest in the world, so many of their immune systems are already compromised and proper oral hygiene is paramount. On a positive note, one thing I always love is the kids get really excited to receive their first toothbrush! They'll hold and caress it like a prized, sacred possession and their eyes light up at the special gift. Seeing that fuels me every single time I get over there to serve. So to answer your question, they find natural ways to clean and protect their teeth and I'd imagine it's the same thing people did in the historic days. Edit: Tried to simplify",
"They lived with dental problems. Our wisdom teeth is an interesting aspect of this. Back then, we would have certainly lost some teeth when our wisdom teeth began to set in. Today, we don't have room in our mouth to for them, so we have to remove them surgically.",
"Read up about Dr. Weston Price he wrote about this kind of stuff. He was one of the first to find out that groups of people who ate a lot of grains and sugars had poor oral health compared to grouos of people who didnt. So while you had rich Europeans suffering tooth decay you had poor African and South American tribes men with relatively little dental problems. Pretty interesting. URL_0",
"They also lived shorter lives back then for plenty of other reasons. So, they didn't have to eat for as long as we do."
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6ftsaw | Why do batteries need to be facing opposite directions? | Repost | explainlikeimfive | {
"a_id": [
"dikvhpb",
"dikvn0d",
"dikvgyo"
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"text": [
"It makes manufacturing slightly cheaper by allowing a shorter length of wire (or simply a metal shunt) between batteries connected in series.",
"They are usually wired in series and the cover or holders have springs or metal tabs that connect the batteries top to bottom. AA or AAA , C and D batteries produce 1.5 volts, so two in series gives us 3 volts, four in series 6 volts, six in series 9 volts, etc. Making you put them in upside down from one another reduces their product cost by shortening the path from one battery to another.",
"It is primarily for design purposes. By alternating the direction they don't have to have the wires cross over one another."
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6fudn9 | Why does glue not get hard and stick to its original container? | Repost | explainlikeimfive | {
"a_id": [
"dil10lj",
"dil1ufi",
"dil11as"
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"text": [
"Often it is the case that water is acting as a solvent, so as to prevent the glue from solidfying into a self-stuck mass. The amount of air inside the container is insufficient in the short term to evaporate that water. Once you've applied the glue to some surface, it can more readily interact with the air and lose its water content.",
"Glue needs a reaction to solidify. Superglue reacts with water, PVC glue melts the PVC it's in contact with, and other glues generally have a solvent (like water in Elmer's glue) evaporate leaving behind the solid glue. So the short answer is that the container keeps whatever reaction is supposed to happen from happening. If you left the cap open for example, water (in the form of humidity) could get into a superglue bottle and react with the liquid glue.",
"because the container is (supposedly) sealed, so the solvent (ie, water) in the glue cannot evaporate."
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6fvtu5 | Restaurants brag that their food is never frozen. How badly does freezing food really affect taste and quality? Or is it more of a marketing thing? | Repost | explainlikeimfive | {
"a_id": [
"dildbff"
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"text": [
"it all depends on the food and how it was frozen. If food is frozen slowly, then ice crystals can form in and around it. These crystals damage the food and cause unpleasant textures. The act of thawing can hurt as well. Vegetables lose moisture as they thaw. however, typically this is a marketing gimmick. When flash frozen food loses very little. The implied message is that \"Our food is very fresh\" which isn't necessarily true either."
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6fx6y6 | Why do Homeowner Associations hold such tremendous power? | Repost | explainlikeimfive | {
"a_id": [
"diloulq",
"dilou08"
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"text": [
"Because you voluntarily enter the agreement. No one forced you to buy the house, and you may sell the house according to the rules you yourself agreed to when signing that contract. They wield the power the contract gives them, and can pretty much put in whatever they like as long as it doesn't conflict with existing law.",
"HOAs are entirely voluntary. If you don't want to join one, you simply don't purchase property governed by an association. That'll be pretty hard to do if you want to live in a place with shared property (like a condo building), but it's quite easy if you want to live in a house. There are plenty of horror stories about HOAs on reddit, but the good that a lot of them do goes mostly unnoticed."
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6fxu7m | Statute of limitations - why? | Was just reading a news arrival about a Japanese murderer who has been on run for 45 years and their statute of limitations for murder (15 years) had been abolished in 2010.... My question is why is the statute of limitations a thing in some countries? If someone is caught and evidence proves it was them they should be able to get convicted 1 year or 70 years later? | Repost | explainlikeimfive | {
"a_id": [
"dilvab7",
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"text": [
"The statute of limitations is in place because as people age, memories become less accurate and more prone to influence. Being able to find witnesses for an alibi Also becomes less realistic. Imagine having tok explain where you were on 5/4/1987. Also, physical evidence deteriorates and being able to refute evidence using forensic tests becomes less realistic or accurate. There are a few other factors, but the main point of a statute of limitations is to ensure that a defendant has a realistic opportunity to defend themselves effectively against the charges being filed.",
"Let's say someone commits a crime and doesn't get caught. They get nervous, decide to clean up their life, and go legit. Twenty years pass and they have a family and a stable, society-improving job when someone finds out about the crime. At that point, does punishing the crime help anyone? No. Society is down a productive worker and a good parent for rigid, ideological dogmas of justice. Everyone is worse off if you punish that crime. If the guy doesn't go legit, he continues to commit crimes. Eventually he'll be caught, and by that time he'll have enough crimes on his record to go away for a long, long time, even if some of the earlier ones fall by the wayside. That's why. It's to encourage people to go legit even if they never turn themselves in."
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6g3vfi | How exactly does fat exit my body after a workout? | Repost | explainlikeimfive | {
"a_id": [
"din9bdi"
],
"text": [
"Fat (triglyceride) is made up of Oxygen, Hydrogen and Carbon. When 'burned', the fat is combined with Oxygen from the atmosphere to create CO2, which you exhale. About 85% of the weight you lose is exhaled as CO2. The remaining ~15% is turned into water, which you expel in your urine."
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6g60l1 | Why do birds fly in front of cars? | Repost | explainlikeimfive | {
"a_id": [
"dinsfy2"
],
"text": [
"Meanwhile on BirdReddit... Why do big hunks of rolling metal squash thousands of us every day for no reason?"
],
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3
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6g7uo7 | How can we visualize our own galaxy , How do we even know it looks like a white round path from outside as we can see in everyday picture of Milkiway ? Or is it artist mere imagination ? | Repost | explainlikeimfive | {
"a_id": [
"dio5kp1"
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"text": [
"You answered it yourself. Any picture of the milky way that isn't of the night sky is an artist's rendering, or a computer rendering. Now, some random person isn't flipping paint on a canvas willy-nilly, no. These renderings are very accurate. Astronomers have use various techniques to measure the distance to stars, with more accurate distances as techniques/technology improves. These measurements have been analyzed and we have found that the stars grouped up in the arms of a spiral galaxy. This gave us the ability to approximate an image of the milky way, because, even though we know how far the stars are, remember, it takes millions of light years for some star light to reach us, so their positions may not be accurate. So, the artist or computer may fudge something, but the end result is close enough that I don't think anyone cares."
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6gbr95 | Why does a word start to sound weird after saying it multiple times? | Repost | explainlikeimfive | {
"a_id": [
"dip0xl8"
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"text": [
"Because it begins to lose your association with the idea it represents... IE - you say the word \"little\" and your mind immediately pictures something small.... if you continue to say \"little\" on repeat for a minute, it is just the sounds of the word coming out of your mouth and not the mental association with the idea."
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6gce9q | Why do humans enjoy drinking hot and cold water, but find lukewarm water unsatisfying? | Repost | explainlikeimfive | {
"a_id": [
"dip97ut",
"dip98oc",
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"text": [
"My best guess is lukewarm = stagnant and stagnant in the wild means probably infected with all sorts of stuff. Well and spring waters are usually cold(ish). Not likely to come across hot water naturally so maybe the warmth is just comfortable and doesn't have to do with the water itself?",
"I love luke warm water. It's easy to drink in large amounts quickly. Makes hydrating after a night of drinking super easy.",
"I'm not so sure about hot water, but I do know that cold water sends the same signals to your brain that says that it is quenched. When you drink cold, salty water, the cold quenching sensation will actually overcome the thirsty sensation that people feel when you drink salty water."
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6gcgju | Before the 20th century, why did soldiers walk in a straight line formation towards the enemy? | Repost | explainlikeimfive | {
"a_id": [
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"text": [
"Short answer: Because battles are confusing as hell, and smooth-bore firearms are not terribly accurate. A smooth-bore infantry musket or musketoon of the 15th-19th century has an effective range against a man-sized target of 75m. Maybe 125m if you're a fine marksman with a quality weapon and good ammo. The best soldiers could fire 3-4 shots a minute at drill, with nobody shooting back at them. So a musket is really a piss poor self defense weapon against multiple attackers. You might get one of them, and then you have an empty gun vs however many are left to run up and stab your ass to death, and if they have horses you're super boned because you can't even run away. So you never, ever want to get caught alone. You want to be with your bros both because volley firing is more effective than one guy firing alone (more bullets equals more hits, and volleys are terrifying things to stand in front of) and because 100 guys with muskets and bayonets stand a much better chance fighting hand-to-hand as a unit than they do individually. This is where flashy uniforms, giant flags, bugles, crazy helmets, plumes, and other flamboyant costumes come in. Firing a musket is incredibly loud, and it produces a ton of thick smoke. 100 guys firing at once is basically an instant smokescreen. Unless there's a stiff breeze after 2 or 3 volleys you're going to be mostly deaf and blind. So you want your bros to be easy to spot in the smoke (bright red coats, huge silly hats, flags!) so you don't get left behind if they decide to move. tl;dr: 100 guys milling about alone in the smoke = cavalry meat 100 guys well-formed in ranks = killing machine",
"Because they used muskets. Muskets were slow to load, and fairly innacurate because they were smooth bore. As such you fought in formations that let you volley attacks from a group of men toward another group of men increasing the odds of you hitting the enemy. These tactics were starting to be phased out by the American Civil war as they started to use rifles, breach loaded weapons and other advancements that increased individual effectiveness of a soldier but it was still mostly volley style attacking. Even WWI used this style of fighting when they were not trapped in the trenches.",
"There's a lot of different factors there, but they basically boil down to a couple questions for each historical moment you're thinking of: How important is massed line infantry, and how effective are firearms against massed line infantry? So when the first firearms were invented battles were fought with big, dense formations of infantry protecting archers and important units. This was necessary for morale and communication purposes and for defense against other massed formations. You couldn't disseminate orders far and wide or micromanage small troop movements with radios and such so troops were grouped up where they could easily be commanded en masse and they were drilled to do their simple jobs automatically. Loose formations were safer against ranged attacks but they'd be split open by charges, especially from cavalry, and that leads to panic, breakdown, and exposure of the vulnerable parts of the army. Breaking those formations down was how you won; the majority of combat casualties in this kind of warfare were inflicted after the battle was already decided. A formation might only lose 10% of its members before it splits and loses cohesion but then cavalry can charge straight through, killing everyone in their path. At the same time early firearms were inaccurate and prone to failure and didn't pose such a huge threat to massed formations that they needed to spread out. As guns became more sophisticated and we got better at making effective use of them those big box formations became less effective. For a while warfare was dominated by muskets and pikes, and then the bayonet obviated the pike too. By the revolutionary and civil war we were already starting to experiment with more irregular formations as guns got better at mowing down dense formations, but the threat of cavalry was still there to keep troops dense. Machineguns and advanced artillery finally made line troops obsolete and learning that lesson the hard way is what made WW1 such a uniquely hellish war. There weren't really any counters to defensive emplacements like machineguns and they could chew through line troops easily so the fighting tended to grind down into trench wars where the only way to advance was to throw thousands of people into the meat grinder. Then tanks came around and could advance into machinegun and even certain kinds of artillery fire and offensive warfare became viable, but the sheer power of modern firearms to deny area and kill people en masse made line troops useless. Additionally, advancements in communication technology and more sophisticated training allowed armies to break up into smaller and more independent units with a more flexible chain of command, so you didn't need to have them all together anymore.",
"Why march in a line? Because the goal was to create a literal sheet of lead. Why? Because as mentioned before, aiming as inaccurate. Why they did it in WWI after the hard lessons of the Civil War is the better question"
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6gct39 | Why does looking at/near the sun make me wanna sneeze? | Repost | explainlikeimfive | {
"a_id": [
"dip9vhm"
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"text": [
"It happens in a certain group of people, it's commonly called [the Photic Sneeze Reflex]( URL_0 ). It's somewhat related to allergies (in that medication that you take to combat allergies will also prevent the sun sneezing)"
],
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6ggamo | Why does the power go out when there's a storm? | Repost | explainlikeimfive | {
"a_id": [
"diq16j2",
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],
"text": [
"As said before, lightning strikes can trip the service line breakers. Also, trees can land on lines, wind can knock down power poles, junction boxes can get water in them, lines can get water in them (if poorly maintained), car accidents can take out power poles or junction boxes, wind can knock down lines and poles. Many, many reasons.",
"If the power consistently goes out where you live in a storm you live in an area supplied by overhead power lines and they are probably being struck a lot. This trips circuit breakers and they are probably leaving them open till after the storm to prevent them constantly opening and closing again as this can wear them out over time."
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6ghrk6 | the differences between England, Britain, and the United Kingdom | Repost | explainlikeimfive | {
"a_id": [
"diqd30a"
],
"text": [
"[CGP Grey has a great video explaining this.]( URL_0 ) England is a country, Britain is an island, and the UK is a nation. The UK contains the countries of England, Scotland, Wales, and Northern Ireland. The island of Britain is home to England, Scotland, and Wales."
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6gkiep | Why do we have nightmares? | Repost | explainlikeimfive | {
"a_id": [
"diqzgg5"
],
"text": [
"Scientists aren't entirely sure why we have *any* dreams, let alone bad dreams like nightmares. There's a few theories, but nothing's been proven. Some psychologists believe dreams are our mind acting out fantasies, fears, and repressed desires. In sleep, our mind is unrestricted by the *superego*, the part of the mind concerned with morality and social rules. Sigmund Freud believed dreams were a \"royal road to the unconscious\". Some more modern neuropsychologists think dreams might have to do with our brain encoding information into long-term memory, and this is why dreams are often based around events that happened the day before the dream. But again, no one really knows, these are just hypotheses. The science is still in its infancy when it comes to dreams. But what we do know that is that we have dreams during a deep phase of sleep called REM sleep, and that if we sleep briefly but don't get to go into REM stage, our sleep will not be very restful and our brains will endure gradual damage if we go weeks and months without getting a proper amount of deep sleep every night. It's very important to consistently get 7-9 hours of sleep every night. Chronic sleep deprivation is bad for your health."
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6gl94i | How did people clean their teeth before the invention of the toothbrush? | Repost | explainlikeimfive | {
"a_id": [
"dir4kbl",
"dir4ozh"
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"text": [
"Besides what u/stannywilson said, there was much less need for teeth-cleaning tools until the time of the Industrial Revolution. Before that, sugar and other sweet foods were much less common in the diet, and since sugar feeds the bacteria that cause tooth decay it was less necessary to clean teeth (this isn't to say it didn't happen, but it was less pervasive).",
"Hiya. Medievalist nerd checking in! In the period I'm best versed in, someone wanting to look after their teeth could use a rag, wash their mouth out with vinegar or use a split twig (chew on it until the end got soft and bristly, then use those like a toothbrush). People sometimes carried little personal hygiene kits on their belt or in a pouch - the Norse left LOTS of these, and one such kit might come with a comb, an ear-spoon (ancestor to the modern q-tip) to get the gunk out of their ears, a toothpick... People were very much aware of using herbs to sweeten breath too. Having nice breath is mentioned in a lot of contemporary texts as a very desirable attribute, and they'd chew on anything that could offer that. Almost every household, great or small, would have a patch of garden with things growing in it that they could use to cook with, for medicine, pigments and dyes, to keep unwanted pests away or any of those important things. Mint isn't exactly hard to grow, and there's no shortage of other sweet-smelling options. In some very specific ways their oral health was actually somewhat better than ours. They ate much less sugar than we do, so decay and cavities were less common; remains that have been dug up usually show the teeth as *worn down* (or sometimes notched, especially women's teeth...she would have been using her teeth to help her hold her thread/pins/needles as she sewed and developed the classic \"tailor's notch\" as a result) rather than full of holes. People then were a lot like people now. They didn't have a clue what germs were, but they didn't necessarily LIKE being gross."
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6gla5a | Why is it so hard to kill the remaining .1% of bacteria with disinfecting wipes? | Repost | explainlikeimfive | {
"a_id": [
"dir4ok0"
],
"text": [
"These companies don't advertise 100% bacterial elimination because they are protecting themselves against litigation. Let's say you have this super rare, super resistant bacteria that you introduce to a surface. You then use the anti-bacterial wipe to disinfect the surface. Then, you purposefully wipe that bacteria that you absolutely know was not killed onto your skin, and become mildly or even gravely ill because of it. If the advertisements said **100% of bacteria will be killed**, then you've got a lawsuit that could potentially be worth millions of dollars. Advertising **99%** instead removes the ability for people to sue based on super-resistant bacteria."
],
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6gmg9s | Why do people stick a 'SOLD' sticker on a previously 'FOR SALE' house's billboard? | Repost | explainlikeimfive | {
"a_id": [
"dirdee3"
],
"text": [
"Because it's still an advertisement for the real estate agency, and it shows results. You see a \"sold\" sign and people can see that the agency is doing its job."
],
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5
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6gngxt | How do we keep from falling off the bed when we're asleep? | Repost | explainlikeimfive | {
"a_id": [
"dirlf02"
],
"text": [
"When you fall asleep part of your brain is still awake and functional. So you are able to maintain the minimum mental capacity required to keep you safe and alive. This involves a simple reflex to not fall off the edge of the bed."
],
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3
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6gph08 | Why does 70 degree weather feel better than 90 degree weather, even though your body temp is 98.6? | Repost | explainlikeimfive | {
"a_id": [
"dis2q8m"
],
"text": [
"Your body is constantly generating heat. Heat is a byproduct of metabolism, and metabolism is basically all the chemical reactions that keep us alive. 90 degrees (or 32 for everyone else) is pleasant enough when you're not hard at work, when you can sweat freely, and when it's not too humid for that sweat to readily evapourate, and 60 feels fine when you're very hard at work too. Basically, you generate more heat than you need to keep your body warm when it's 90 degrees out, and that also begins to approach conditions where it's difficult for your body to shed heat quickly enough to maintain the proper temperature. Around 70 (21), that's a good balance, in general, for the heat generated at resting and working metabolism, countered by the body's natural cooling systems. TL;DR our bodies are little chemical furnaces and need the environment to be cooler in order to shed excess heat."
],
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6gs1ys | why does the sun seem to move faster when it is setting? | We sat watching the sunset last night in Cuba, and it took about 10 minutes to go from about an inch above the horizon, (from our perspective on the beach) to totally gone. Yet it will stay in the sky literally all day... | Repost | explainlikeimfive | {
"a_id": [
"disl6jo",
"disl7lv"
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"text": [
"It just looks like it is moving faster when next to the horizon, an optical illusion caused by lack of any reference in the sky",
"Lack of a point of reference. When the sun is up in the sky and you look up at it (in it's general direction, never look directly at the sun), there are no points of reference by which you can gauge its rate of motion. When the sun is closer to the horizon, you now have points of reference (the horizon itself, and any other major features) that allows your brain to judge its speed."
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6gyhpv | How is a microwave able to warm up food but not things like plastics, papers, glasses, etc.? | Repost | explainlikeimfive | {
"a_id": [
"diu39ye"
],
"text": [
"Microwave oven work through something called Dielectric Heating. It only works on stuff that is made of a Dielectric Material. When a dielectric material is in a magnetic field, the molecules turn to face the direction of the field. A microwave from the viewpoint of a stationary molecule is a rapidly changing magnetic field. So the molecules starts turning quickly back and forth to follow it. This rapidly turning is the heat the microwave causes. Things like water, fat and sugar are dielectric materials, so they heat up. Things like glass and some plastics are not dielectric materials so they don't heat up. Often a material is dielectric because the molecule has more positive charge at one side then on another side. Things like glass molecules are made out of molecules that don't have any built up charge in any particular place."
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6gykbb | What determines the value of currencies around the world? | Repost | explainlikeimfive | {
"a_id": [
"diu41xe",
"diu52n2"
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"text": [
"Nowadays, virtually every currency is what we call \"fiat currency\". It means that is not backed by an actual good (i.e. gold or silver) but by a government. Economic actors (people, businesses, markets, etc) put trust in governments to be able to provide currency because of their control over a country's economy and their ability to tax it. The value of a currency relative to its area of use is determined essentially by how fast the Central Bank (the government issuer of currency) releases it. This is done by setting an interest rate which determines the cost of \"new money\" put in the economy. When the interest rate is equal to the growth rate of the economy, the currency's value is stable. When the interest rate is lower than the growth, the currency enters the economy too fast for the economy to generate the corresponding value. The currency is then less valuable, prices go up. This is called inflation, the reverse situation being deflation. Both inflation and deflation have economic strengths and weaknesses, it is the job of Central Banks and political technocrats to determine how to use these tools for the benefit of the country. As to the value of a currency relative to another, currencies are traded on markets know as Foreign Exchange Markets or FOREX for short. It is then a classical game of offer and demand, the exchange rate is the result of buyers' price meeting sellers' price. The fluctuation of exchange rates is the result of the perception of the different countries economic strength and perspective.",
"The really short answer is the market forces of supply and demand. The long answer is far too complex to explain in an ELI5 format due to an virtually unlimited amount of variables that impact currency movements. The shorter answer would be interest rate differentials between different economies. The answer i'm providing assumes a long term outlook on currency movements, short term can be completely random or caused by something as simple as a Trump tweet. Here's how this works in ELI5 fashion, Let's say you and your neighbor are both farmers, he grows oranges and you grow apples. For the past 2 years it looks like he has been growing more and more oranges meanwhile your harvest has only gotten worse. You can sort of afford for this to continue but why would you when you could get some extra oranges for no added effort? i mean you were going to farm anyway what does it matter what you grow? You decide to switch from apples to oranges and speak to your neighbour about exchanging some apples for oranges and he tells you that he would happy swap with you but at a 2 apple seed to 1 orange seed ratio. You think this guys an idiot and out to rip you off and as you're leaving you notice your mate from across the road is also coming to the neighbour with his apples. You go back to the orange dealer the next day and now he demands 3 apple seeds for 1 orange seed. You tell him to go stuff himself. This is how and why currency movements occur from a fundamental perspective. Just change the farm to a thriving economy, oranges to US dollars and apples to Australian dollars and you have the AUD/USD exchange rate. Oranges are safe to farm (risk free, investors love not losing money) so there's little downside from changing from apples to oranges and it makes sense to because it adds no extra work for you but you have more food to eat (better returns on investment or higher interest rate). However your sneaky mate from New Zealand has noticed this as well and decided to do the same thing (increasing demand) which essentially made it more expensive for you to invest because mr orange grower realises his oranges are worth more than he thought. Multiply this concept by however many investors there are in the world and you have the reason as to why currency values change. One thing to note is that there doesn't need to be an increase in demand for oranges for the exchange to move. What if there was some sort of vegan Apocalypse and the zombies have eaten all the oranges? suddenly the world is full of apples and zombies but in any case the oranges are now worth more apples because you need to steal them off vegans"
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6gzdgs | why did older TV show have laughing tracks. | Repost | explainlikeimfive | {
"a_id": [
"diu8q73"
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"text": [
"Because they were originally filmed in front of a live studio audience. Producers believed that audiences would miss laughing along with others and felt it would make for a better experience. Contagious laughter works but using the same track and tacking a laugh on every joke eventually backfired."
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6h09gm | Where did the stereotype for Vikings come from? | Repost | explainlikeimfive | {
"a_id": [
"diufmdk",
"diuhqjf"
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"text": [
"From the people whose monasteries they burned down and stole from. *Norsemen* were relatively peaceful. All vikings, by definition, were warlike because viking was a job description for pirates, not a society.",
"Most of it is not really a stereotype. The word \"Viking\" in old Norse means \"raider\" or \"pirate\". So all vikings were the portion of the Norse population that were very violent as they raided other communities. Thus they are pillagers of lands. They were bearded traditionally, so I am not sure why you think they were clean shaven. Almost no one in Europe north of Italy was clean shaven till WWI as a cultural norm. They were taller than many other European groups, though they were not 7ft tall on average. Horned Helmets is a false stereotype. That is from Wagner's Opera \"The Ring Cycle\". They were not as violent as we see them in modernity, but they were more violent than most of the rest of Europe at the time. It was common for disagreements to be settle with one on one combat. It was common to kill each other by accident and they had strict cultural rules about reporting such incidents. And of course they went raiding nearly yearly due to having poor climate and more populations than they could provide for natively. The notion of them being a peaceful bunch did not happen until late in their history when they switch their seafarers to being traders primarily instead of raiders (though they still raided) and they started to convert to Christianity. While they still worshiped their war gods they were very violent. As for hygiene there is not really a stereotype that they had bad hygiene, though all seafarers would have to some extent."
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6h0isr | Why are non-human or non-uniquely-identifiable figures allowed to run for office in the UK? | Repost | explainlikeimfive | {
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"diuhwdx",
"diuhxkc",
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"They are all people running a campaign using pseudonyms, which are allowed so long as they aren't offensive or likely to cause too much confusion. For example, Lord Buckethead was a guy named Jonathan David this time around and when they counted votes the votes were for \"Jonathan David, known as Lord Buckethead.\" Similarly, Elmo is a guy in a large Elmo suit. The person who is actually running has to register and submit identifying information to become a valid candidate.",
"Lord Buckethead is a real human, and evidently a UK citizen. There is no law against legally changing your name to something silly. There is no law against wearing a silly costume when campaigning. This person is taking advantage of these flexible rules.",
"Yes you do have to be a real person to run for MP. You are allowed to run under a pseudonym though, which is why Lord Buckethead was allowed to run as Lord Buckethead instead of whatever his real name is. You don't strictly have to be a UK citizen. Irish and Commonwealth citizens are also allowed to run for MP."
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6h10v5 | Why RAM is necessary in PC? Why not some part of Hard disk to be used as RAM? | Repost | explainlikeimfive | {
"a_id": [
"diunjt7",
"diulyc1",
"diumf51",
"diumgb3"
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"Imagine that you want a bag of chips. They are currently in your pantry. Now, each time that you want to eat a chip (or a handful, I'm not here to judge) you have to walk to the pantry and get a chip. There's tons of storage space in the pantry so you can put all kinds of chips in there however it takes you forever to eat your chips and you're missing out on whatever you might be watching on TV. Of course, we don't do this, instead we bring the whole bag of chips and whatever else that we need and put it on the coffee table next to us. Now we can eat those chips more easily. We can't keep as much stuff there but we generally don't need a whole lot of other things at the same time. You even have room for your chip dip and your soda. It's all easy to get to and much faster. When we're finished, we put the chips back into the pantry, the dip back into the fridge, and whatever else we had. The coffee table is now empty again since it's not for permanent food storage. Your computer works in a similar fashion. The chips are whatever program or data that you're currently working with (or on). We could keep going back to the hard drive for it, but like going to pantry for every chip, that's not very fast or efficient. So your computer loads up whatever it's working on into RAM for quick and easy access. Now, like your coffee table, RAM is not for permanent storage just for quick access so when your computer shuts down it actually just makes everything on the coffee table disappear; it just disappears into nothing and is not saved anywhere (yes, there are exceptions to this, but for our purposes this will suffice). Also, if you get a bigger coffee table, then you can snack on more things at the same time. The same goes for more RAM. If you get more RAM then your PC can snack on more things at the same time unless Chrome sneaks in and gobbles it all up first.",
"It can be, that's what virtual memory is. The problem is, hard drives (even SSD) are a lot slower than RAM. RAM also has its own dedicated data bus, whereas the hard drive will share its data bus with at a minimum other SATA devices.",
"The reason it's \"necessary\" is because of the speed. From the article [The Pathologies of Big Data]( URL_1 ) Hard Disk speeds can be 150,000 times slower at random read and write access than RAM is ([Figure 3]( URL_0 )).",
"In theory it can. When there are not enough space in RAM memory operating system cretes special file called Swap. It will act as RAM, but will be orders of magnitude slower than proper RAM memory. In good old Win XP days allocated swap size had to be atlest 2x the size of total available RAM space."
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6h1a0m | What happens when a computer file is deleted? Does the data actually vanish from existence or does it continue to exist in a dormant state? | Repost | explainlikeimfive | {
"a_id": [
"diuobtu",
"diuoffh"
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"text": [
"The operating system removes any reference to the file and marks the area that the file took up as free. The file may or may not eventually be overwritten by new files. Files can be recovered before they are overwritten. You can also securely delete a file, and the space that it takes up will be immediately overwritten, making it nearly impossible to recover.",
"depends... on a magnetic disk drive, typically all it does is \"forgets\" where the data was. its like taking the street number off your house. there are recovery tools that will read the raw data on the drive. This is relative childs play, you can get free apps that will do this level of recovery. Alternatively, there are format programs that will actually WRITE 0's and 1's over the drive multiple times to completely eliminate any residual image of the former data. It will do it multiple times because if your REALLY ambitious with advanced recovery software, it may be able to even detect what it was \"before\" the last overwrite. flash drives are the same, but its much easier to just reset all of the bits, theres no residual magnetic charge."
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6h1wat | Why isn't there a disease that's the opposite of depression? | Repost | explainlikeimfive | {
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"diutibb",
"diutn7z",
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"text": [
"There sort of is. Just like there are depressive episodes, there are manic episodes. During a manic episode you may feel euphoric, like you are super powerful, you can do anything. You make big plans, you're gregarious, you're thrilled, excited.",
"There sort of is, frequently described as [\"Mania\"]( URL_0 ). Mania is characterized by extreme hyperactivity and arousal (not necessarily the sexual kind), frequently along with delusions stemming from the overactivity of the relevant brain sections.",
"The opposite of depression isn't 'joy' or 'happiness'. Those are the opposites of 'sadness'. Depressed people typically don't even feel sad. They experience 'anhedonia'. Depression is about numbness, exhaustion, and emptiness. The opposite of that is closer to mania."
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6h2d1j | what exactly are knotted muscles in your back and where do they go when massage therapists work them out? | Repost | explainlikeimfive | {
"a_id": [
"div324v",
"div06u1"
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"text": [
"Doctor, and D.O. here (we kinda love this type of stuff, and are somewhat like massage therapists that wasted more of our lives lol). A knotted muscle is like what these guys are describing, it's just tight when it shouldn't be. The back is a good place to think of an example to conceptualize it, but you also have to understand that EVERYTHING in the body is connected to (and therefore impacts) almost everything else. Think about a muscle in your lower back that starts to contract (when it kinda really shouldn't), no big deal right..? Well sort of yes a big deal! 1st off that means the spine gets pulled to that side, specifically 1 of the vertebrae will be rotated or bent to that side, which puts weird stress/strain on the vertebrae above and below (can cause pain and weird tingling), additionally that muscle also (lets say) attaches to your hip... when it tightens it tries to rotate your hip bone up, now that stretches your hamstring (which doesn't like to be stretched past a certain point) so your hamstring now starts to tighten up and contracts too. Now you have a small (ish) issue with 1 muscle group that has created an issue of pain/tension/bony immobility from your lower back (or higher), through your pelvis, down your thigh, to your knee (or lower). Fortunately for us we have learned that several things can calm those muscles down, #1 being pressure applied to the muscle (or surrounding muscles), somehow our muscles evolved that pressure on/around in gentle and direct focused ways will cause them to relax. Another way almost everyone uses/knows about, stretching! When you stretch a tight muscle it will cause at least SOME of those fibers to relax because they need to relax or they tear (that's why you don't wanna stretch SUPER aggressively if you have a tight muscle, but gentle stretching helps!). Another less well known way is to use an opposing muscle. Going back to our tight hamstring example, if you gently but forcefully use your quadriceps (against resistance is best) it will help your hamstring to relax. Our body is smart enough to know that you shouldn't really use two opposing muscles at the same time (quad/hamstring, tricep/bicep) with the same force, otherwise you wouldn't do anything (this is kinda different for fine motor movements but lets not make this discussion longer than it is :P) sooooo using your quad automatically causes your hamstrings to start to relax, and if you repeat that, it will continue to help it relax. BUT you didn't solve the problem in your back!! So the tight hamstring will come back... this is why (again) everything in the body is connected, and also why some people get the same tight muscles (or the same bones that \"pop\") over and over again. Because they treat one of the resulting issues, without treating the main one. Hope this helps!! And hope it wasn't TOO long and boring.",
"I'm not a doctor. I believe that knotted muscles are muscles that are contracting when they should be constricting. Think of making a clenched fist. A massage therapist would be working to relax your fist to extend the fingers out, with the fingers being the muscle itself. Again, not a doctor."
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6h2q1c | what is a terraflop? What advantages does this bring to me? How does this correlate the new Xbox one x? | Repost | explainlikeimfive | {
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"div2sty",
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"text": [
"FLOPS is a measure for FLoating point Operations Per Second. This measure indicates the speed at which a computer processor can chug through calculations. \"Tera-\" is a prefix meaning \"1000 times Giga-\". You might have heard of Gigabytes or Gigahertz? Those are just the \"giga\" ordinal for bytes and hertz. \"Giga-\" means \"1000 times Mega-\", \"Mega-\" means \"1000 times Kilo-\", and \"Kilo-\" means \"1000 of something\". So: 1 Teraflops = 1000 Gigaflops = 1,000,000 Megaflops = 1,000,000,000 Kiloflops = **1,000,000,000,000 flops**. So a 1 Teraflop processor can calculate 1 trillion operations per second. For comparison, there exist supercomputers that run upwards of 30 *Peta*flops, where 1 Peta = 1000 Tera. Quite the head-spinner, that one. :) --- **How does that benefit you with the Xbox One X?** Supposedly, the more FLOPs, the better. The Xbox One X will be coming out with a GPU that processes at 6 teraflops, or \"TFLOPS\", meaning it comes close to the performance of an nVidia GTX 1070 ([which operates at 6.5 TFLOPS]( URL_0 )). That should produce some decent high-res visuals at a good framerate, if the console is all it's chalked up to be. Edit: silly me, I forgot Giga! And I call myself a techie. :(",
"FLOP stands for FLoating point Operations Per second. Graphics and physics calculations often use floating point numbers instead of integer numbers. So Flops is a rough measure of how much graphics or physics calculations you can do. It follows the SI standard of units which goes kilo, mega, giga, terra, peta, etc. So one terraflop means a trillion floating point operations a second."
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6h6wqp | So why hasn't the water crisis in Flint, MI been fixed yet? | Repost | explainlikeimfive | {
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"text": [
"Its technically been \"fixed\" for well over a year - which is when lead levels in the water returned to normal. You still hear about it because they are still replacing the city's pipes and it won't be considered fixed until all of the pipes have been replaced - which is a very expensive, time consuming process. What happened is that the city's pipes are made out of lead. This isn't uncommon - lead pipes were widely used until the 80s and Flint's water infrastructure is significantly older than that. Ordinarily lead pipes are fairly safe. Lead only leaches out of very old pipes and even then usually in amounts that don't pose a public health risk. However, for a period of about 13 months Flint used water from the Flint River that had an unusually high natural level of chlorine in it. That chlorine caused damage to the city's pipes, causing them to leach lead into the water supply. Once Flint switched off of the Flint River water, levels of lead in the water slowly returned to normal. However, the city is still replacing *all* of the water mains out of an abundance of caution. This is a very long process because it involves digging up every street in the city, removing the existing water pipes, and then replacing them with new pipes. For the same reason, its also a very expensive process. Due to the difficulty and cost of the project, the current budget of ~$50 million per year will see the project completed sometime in 2020. If the water posed a current health hazard you would likely see more money going to it to move that timetable up, but since the water is currently safe to drink the project is just being treated like any other large public works project."
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6h7ax2 | What is "jury nullification" and what is its purpose? | Repost | explainlikeimfive | {
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"There is no \"purpose\" to jury nullification as it is just a side effect of the jury system. The jury might decide that a defendant is guilty yet refuse to convict them because they don't agree with the law. This isn't intended and would generally be considered a perversion of justice, but the jury decision stands regardless.",
"It's a finding that doesn't actually match the jury's belief, for instance if they conclude a suspect is guilty but find him innocent. It can have a variety of 'purposes' such as disagreement that the law in question is just. A jury might find a person innocent of possession charges, even if they know he is guilty, because they don't believe possession should be illegal, for instance. Or they might find a person guilty despite knowing he/she is innocent because they have some animus against the defendant. To be clear when it comes to 'purpose', it is a very contentious subject, and something you will find many legal professionals considering a violation of the Juror's oath, but it is also not something that can necessarily be prevented or necessarily should be prevented.",
"CPG Gray actually did a really great [video]( URL_0 ) on this awhile back. Edit: a missing space",
"The \"what\" of jury nullification has already been answered. And as others have said, it doesn't have a specific purpose: it's just a side effect of trial by jury. As to whether or not it's a good thing, that depends on your point of view. In favour of jury nullification, juries may acquit people because the law they're accused of violating is a stupid law. For example, suppose it were a criminal offence to wear a green shirt on Fridays: juries would probably nullify that one all the time, until the law enforcement agencies stop trying to enforce it. In effect, jury nullification can provide a sort of sanity check. Arguing against jury nullification, it has been used in the past in very sinister ways. For example, go back a few decades and you'll find several cases of all-white juries in parts of the Deep South finding whites \"not guilty\" of the murder of blacks despite overwhelming evidence."
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6h8qsr | Why do airplanes flying above me appear to be going so slow even though they are traveling several hundred mph vs my slow walking pace? | Repost | explainlikeimfive | {
"a_id": [
"diwdabi",
"diwdkyo"
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"text": [
"well, how do you gauge their speed? tiny dot in a big sky, no frame of reference. if they travel a mile at their distance, it might be a fraction of a degree change in your perspective. with nothing to mark the change against. Basicly, they appear to be going slow because your not used to judging speed of objects in that are that far away.",
"Because the sky is huge and your pavement is small. [This may help explain.]( URL_0 )"
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|
6h909s | Why is depression a thing, but the opposite isn't? In other words, why is it chemically possible to be depressed, but you never hear of people who are chemically so happy that basically nothing bad can get them out of the state of euphoria? | Repost | explainlikeimfive | {
"a_id": [
"diwfoda",
"diwfn9w",
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"text": [
"That would be [mania] ( URL_0 ). It is not an exact mirror image, but states of heightened emotions, energy, decreased need for sleep and hyperactivity do exist and they present with several different disorders. (Bipolar tends to be the best known one)",
"The opposite is a thing. It is called being manic. People have the condition on its own, and in combination with depression when they are bipolar.",
"The opposite of depression isn't 'joy' or 'happiness'. Those are the opposites of 'sadness'. Depressed people typically don't even feel sad. They experience 'anhedonia'. Depression is about numbness, exhaustion, and emptiness. The opposite of that is closer to mania."
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"https://en.wikipedia.org/wiki/Mania"
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|
6haol4 | Why do painters wear all white? | Repost | explainlikeimfive | {
"a_id": [
"diwwurk",
"dixgdsu"
],
"text": [
"Traditionally white clothes were worn by painters as it was the easiest color to clean as it could be bleached.",
"It also helps prevent cross contamination, ie your less likely to brush up against things if you know you have paint on you."
],
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|
6hatk9 | How does Rain have a "smell" if it's just water? | Repost | explainlikeimfive | {
"a_id": [
"diwvosr"
],
"text": [
"Plants release oils into soil during dry periods. These are released during rainfall, and they smell. Air pores in soil release bubbles when water hits them. From lightning, the air smells like ozone, and lightning usually comes with rain. It's called [Petrichor]( URL_0 )."
],
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"https://en.wikipedia.org/wiki/Petrichor"
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|
6hcbvh | how does computer performance work? how do things like processor, chip, RAM etc come together to make a computer slow/fast? | Repost | explainlikeimfive | {
"a_id": [
"dix8b6k"
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"text": [
"There's one component that heavily influences your experience with a modern computer, the hard drive. Always get an SSD Modern processors are plenty fast for reasonable workloads, unless you're video editing or number crunching you're probably not CPU limited Modern RAM is cheap enough and fast enough for modern workloads. Chrome will gobble up all your chips no matter how many you give it, but when it runs out of chips how quickly can it get more? When you run out of space on RAM you have to go back to your primary storage, traditionally a HDD which was made of spinning discs, now an SSD which is a really big SD card that lives in your computer. An SSD has a latency measured in nanoseconds while a hard drive takes 7 ms to reach what you need to read. The SSD can also read the data out 10-1000x faster than the spinning discs can, this leads to things opening quicker, super fast boot, less lag, even faster browsing because Chrome needs to keep running back for more space Having more performance does you no good if you won't use it. An i7 is of no use to someone who uses Word to write christmas cards once a year, a strong GPU is of no use to someone who just watches Netflix. Unless that component is limiting the performance then upgrading it yields no noticeable benefit. Your primary storage is almost always limiting maximum performance so the biggest gains are there"
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|
6hept6 | Where does the Layout for QWERTY keyboards come from? | Repost | explainlikeimfive | {
"a_id": [
"dixq5a7",
"dixoxq2"
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"text": [
"The QWERTY layout first appeared in 1874 on the Sholes and Glidden typewriter later renamed to the Remmington No. 1 (yes the gun manufacturer). We do not have the internal documents describing the development of this new model of typewriter and the development of the QWERTY layout. However we do have the advertisements and marketing documents which claim that the typewriter is much less prone to jamming when typing fast. It is still a debated topic to this day how the QWERTY layout helped prevent jams or if it helped at all. We do know that other typewriter manufacturers adopted the QWERTY layout but we again do not have the documents describing why they did so. The only surviving records describing the decision to use the QWERTY layout was after it had become popular and standardized so people did not have to relearn to type when getting a new typewriter.",
"Back in the day when type writers were used, letters were arragned in alphabetical order. But when writing fast mechanisam got stuck becase letter who were used the most were close together. So some french guy i think aranged them in order where to most used letters were the furthest away from eachother. And till today that desing stayed even doe its primary use is obsolete."
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6hhv30 | Why have there been no supersonic air travel services since the Concorde was decommissioned? | One would imagine that modern technology could make the service profitable in ways that we couldn't with the Concorde's 1970's technology. Kind of strange that airline travel speed hasn't improved much in the past 60 years. | Repost | explainlikeimfive | {
"a_id": [
"diyfjqu",
"diyfgg4",
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"text": [
"Supersonic aircraft a expensive to maintain, expensive to fly, and even more expensive to design for consumer level travel. Also, flight paths are limited because of the sonic boom, typically can't fly over populated areas at speed which limits usage to niche markets. They also tend to hold less people than larger aircraft that travel slower.",
"The feats of modern technoogy still haven't changed the laws of physics. The faster you go, the more air resistance you get and the more fuel you have to burn. Fuel costs more than it did back in the 80s",
"One big factor is that people get unreasonably snippy when you break the sound barrier above their house multiple times a day every day of the year. It's basically just Nimbyism, but airlines don't really have a choice but to give in. That means you can only fly from (and to) airports too far from civilisation to be useful."
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6hj1zf | Why does the United States continue the tradition of a two party system? | Repost | explainlikeimfive | {
"a_id": [
"diypc1d",
"diyqaiy",
"diypkqq",
"diypbio"
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"text": [
"Because those 2 parties have an obscene amount of power / influence, and they use that power / influence to prevent others from trying to get a piece of the pie. Why would either party want to change a system which benefits them massively?",
"The two parties in the US are not actually a part of the government. They are civilian organizations that unify to support a candidate during elections. It should also be noted that the two party system is a result of the first past the post winner take all system. The specific parties will shift periodically over time but there will always be a winning party and a primary challenger in such a system.",
"Gathering in a party allows you to access much greater resources, outreach, and political support than being independent. The parties coalesce into a big group representative of a general method of governing. The thing is, if you have all these independents, some can gather before a poll to make a small group of like-minded politicians. They combine their political support bases and are able to win more elections. Then, the group grows, and opposing view groups form as a result. Here's where two party comes in: Some parties will always be more popular than others. Say A, B, C, and D are the parties. In many elections, D is somewhat smaller and never wins. So they go into one of the bigger parties that agree with them. Then, A and B can be a little bigger. C suddenly is losing more and more to these behemoth parties. C then dissolves into the party that shares its views. All's left is A and B. Nobody builds a party to oppose them big enough, because they will never reach the level of these other guys. Sometimes, party B will resurrect and fund party C a little, to get voters away from A, if C is more similar to A but not quite, just so that the A votes get split between A and C and thus B wins. EDIT: [this]( URL_0 ) explains it all.",
"Two party systems are often the result of a Single Member Plurality electoral system aka electoral college. Changing the voting system will probably change the party system since people who may want to vote for smaller parties will no longer believe that their vote will go to \"waste\"."
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6hjdix | why is 18 considered the age when you become an adult(not 17 or 19 or 20)? | Repost | explainlikeimfive | {
"a_id": [
"diys3l6",
"diys4zx",
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"text": [
"\"In the Middle Ages 21 was considered the age of adulthood because that’s when young men were capable of wearing a full suit of armor. 21 stuck until the 20th century. The need for soldiers for WWII, Korea, and Vietnam wars saw 18 years olds drafted and an outcry that they could serve their country but not vote. This led to passage of the 26th amendment lowering the voting age from 21 to 18 in 1971. Source: Children and the Law class in law school and accompanying casebook\" -u/Sneekey",
"It's arbitrary. In Japan the adult age is 20, and its privileges are unanimous. Driving, voting, drinking, all the same. Most adult ages will be between 17 and 21 because it's the end of the teenage years.",
"It cracks me up when people refer to 17 year olds as children and 18 year olds as adults. It's utterly arbitrary but people swear to God there is a defining line at that 18th birthday."
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6hjobh | Why can we (humans) only selectively block out visual stimuli(close our eyes) but have no was to inhibit/delay/shut out tactile, olfactory or audio stimuli? | Repost | explainlikeimfive | {
"a_id": [
"diyv84r"
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"text": [
"The main reason we can close our eyes or blink has to do with maintaining the moisture of the eyeball, and protecting the eye from things like sand, sweat, etc. We can also blink to help remove foreign debris from our eyes. Our ears and nose have little hairs that essentially do the same thing. Long story short; our lids aren't closeable so that we don't have to see things. They're there to protect our eyes, just like our ear and nose hairs are. So, to reply to your further comment: we don't have a way of closing our nose or ears because for their functions, we have no biological need to."
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6hjuf3 | How does vitamin D work? Is it a real substance that comes from the sun or is it created by our body? | I'm pretty sure it's just magic. | Repost | explainlikeimfive | {
"a_id": [
"diz68d0",
"diyw1pk",
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"text": [
"Vitamin D is a real substance. It doesn't \"come from the sun\" at all, the sun just sends energy... Your skin is full of oil and fat and stuff. One of the things it contains is cholesterol. When cholesterol is exposed to Ultraviolet light, particularly \"UV-B\", the incoming photons knock some of the atoms in the cholesterol molecule around. The result of that knocking is Vitamin-D. Now unlike photosynthesis, which only happens in special sub-components of cells in plants, the Cholesterol- > Vitamin-D thing can happen anywhere. Like if you put a blob of it out in the sun on a dinner plate it would convert. You sort of ooze out cholesterol, and then it gets converted into \"vitamin D lotion\", that soaks back into your skin. So there are some surprising things here to \"Get Vitamin-D from the sun\": - Depending on where you live, you may only be able to make significant quantities around noon (or 1pm on Daylight savings time) because that's the only time of the day that enough UV-B can get through the sky. The further towards the poles you get the smaller the window. - If you shower or bathe too soon before you sunbathe (like six hours) you can wash away most of the Cholesterol and there is nothing to convert. - If you shower or bathe too soon after you sunbathe (like eight hours) you can wash away the \"Vitamin-D lotion\" before it really soaks back into your skin. - It is very easy to get sunburnt without really getting any Vitamin-D in your system at all. So basically most people get little or no value from going out in the sun because they don't do it near-enough noon or they are too clean. The wikipedia page for Vitamin D discusses the particular form of cholesterol and how it all happens and looks like a good place to start if you want to know more.",
"Both. In your skin is a substance that reacts with uv light. This converts it into another substances that travels to the liver and is convertee into vitamin D.",
"Just to put this out there... For some reason there are people like myself who can't produce Vitamin D and have to take medication. No clue why. I have to take Potassium too. Kidneys and Liver are fine. I'm perplexed and Doctor is perplexed."
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6hjxe0 | What the 2038 problem is. | Repost | explainlikeimfive | {
"a_id": [
"diyw4jk",
"diyw6fl"
],
"text": [
"Most computers store dates as the number of seconds that have passed since Jan 1, 1970. They use a 32 bit number to store this. In 2038 that number will overflow, meaning that to many computers, dates will appear to be Jan 19, 2038 one second, and Jan 1, 1970 the next second. This could pose problems, just like Y2K posed problems.",
"It's similar to the Y2k bug. Unix systems store dates as the number of seconds that have elapsed since January 1 1970. In 2038, that number (2 billion or so) will exceed the largest number that you can store in a 32-bit unsigned integer. At that point, it will roll over to 0 and systems will think it is 1970 again. Systems are being updated to store this in a 64-bit integer."
],
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|
6hmff2 | How are political parties so evenly split in the US? | Repost | explainlikeimfive | {
"a_id": [
"dizewaq",
"dizex7g",
"dizeeas"
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"text": [
"Because the parties want to win, therefore, they work to make it that way. If an idea becomes unpopular a party will drop it. If an idea becomes extremely popular a party will adopt it or at least make it less of an issue. Let's take gay marriage. [Since 2001 to present more and more people are accepting gay marriage]( URL_0 ). In 2008, Obama was sort of against gay marriage. He said it was a state issue. His party was softly for it though. The reason was the issue was still unpopular. This meant the Democrats could have a bigger tent and include people that were against gay marriage, allowing them to have slightly over half of the vote that year. Now the tables have turned. Gay marriage is a popular issue and the Democrats (including Obama) embrace it as a party platform. And Trump and Republicans? Well, they don't make it an issue. They aren't *against* gay marriage but not for it, allowing them to have people that are for it and against it and were able to get about half of the vote in 2016. So in essence, it's about half and half because the parties are both trying to win, and to win they both need ~51% of the vote. They will change their stances if their stances become unpopular.",
"With two parties, the notion is that they would adapt their policies to balance each other. If there were three, they would each be a third. Since it takes 50%+1 to win, both parties are very strongly committed to blocking the rise of a third party. If you're in a party that loses every time, you need to change something. You change an edge policy to get some of the people to vote for you instead of the other team.",
"Approximately 42% of voters will always vote Democrat and approximately 42% of voters will always vote Republican. The remaining voters are the \"swing vote.\" Those are the votes who are targeted by ads and choose the direction of the nation at each election."
],
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"http://www.pewforum.org/2016/05/12/changing-attitudes-on-gay-marriage/"
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|
6hmjar | Why do bad smells make us throw up? | Repost | explainlikeimfive | {
"a_id": [
"dizfmvl",
"dizf64f",
"dizl89i"
],
"text": [
"In case you ate some of it. It's a biological response to purge toxins from your stomach, if something smells rotten, it probably is rotten and should not have been eaten. now we don't eat such things, but hundreds of thousands of years ago when the response evolved we might have.",
"Basically, most things that smell that bad would be very bad to eat. The gag reflex stops us from eating things that could make us sick. Not sure about the exact mechanism",
"Smell is our primal indication if something is fit to be eaten or contains too many toxins which would cause us harm prior to consumption. Vomiting is a reflex response to food that the body feels will cause us harm following consumption. The sense and reflex exist for the same purpose. A smell is an aerosol of the source (the smell of pizza is a very small part of the pizza floating through the air) and when it enters the body through the nose the same reflex reaction occurs as if it is in the stomach. TLDR: The body will reject smells the same way it would reject food that is eaten."
],
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|
6hn76c | how does double bouncing on a trampoline work? | Repost | explainlikeimfive | {
"a_id": [
"dizqw6n"
],
"text": [
"When you \"compress\" or add weight to a trampoline, you are adding elastic potential energy to the material since it is bound by springs. If you are by yourself, your weight can only push so much before the tension is too strong for your body weight to keep falling (kind of like when you strap those long elastic bands around your waist and try to run away from its mounting point and you cant go any farther at carnivals), so the potential energy is converted to kinetic and you bounce up. When there are more people and, thus, more weight, when timed correctly one person/weight builds tension on the trampoline and that tension is continued when more weight from a second person is applied. Since you came flying in second while your friend just hit the trampoline, you move it from under his/her feet and they don't have contact anymore to receive the bounce. On the other hand, you gain the potential energy your friend exerted on the trampoline AND the potential energy you exert. The material goes down farther, has more potential, and you go flying into another dimension. TL;DR: More weight results in more energy that can bounce you back up higher"
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|
6hp3gv | why you should wait 30 seconds between switching off and on when restarting an internet router | Repost | explainlikeimfive | {
"a_id": [
"dj00jf6",
"dj0608m",
"dj00hth"
],
"text": [
"20 seconds should be long enough. Basically, you need to wait long enough for the capacitors in the device to drain their electricity so that all components that aren't battery-backed completely power down. Otherwise, you may start it back up to find that some bits never actually got restarted.",
"I'd like to add an interesting fact to this thread. There's such a thing as a cold-boot attack, which consists of physically gaining access to a locked computer which is running a program, the contents of which you wish to know. The premise is to turn off the computer, quickly remove the RAM cards, and lower their tempurature to prevent the capacitors from discharging quickly. You then load the ram into your own computer, where a specialised program takes the contents of the ram and unloads it to a nonvolatile disk to be read and data harvested at a later time",
"Power supplies and routers can carry some leftover voltage in the capacitors that keep things running for a bit even after being unplugged. So it takes a little bit to use up that energy and fully shut down. 30sec is a bit much though, 10sec should be plenty."
],
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6hpwz9 | If there are thousands of characters in the chinese and japanese language, how do they type on a computer? | Repost | explainlikeimfive | {
"a_id": [
"dj07s2h",
"dj07g0z"
],
"text": [
"I can explain Japanese, which should cover both. They use a QWERTY keyboard, but there are different software keyboards that intercept what you type. So, they type for instance, nerihamigaki. As they type ne the software replaces it with ね. Replaces ri with り, and on and on. It would do this with each one until it has written ねりはみがきfor them. In Japanese, it starts with this hiragana and then a large list of kanji comes up, with the word you are most likely trying to write as the most recommended conversion:練り歯磨き. This word used both kanji and hiragana, but it could do it with only hiragana words, only kanji words, etc. Oh, and the word used here means toothpaste. :)",
"For Japanese you type in the hiragana characre(which represent sounds) and then the computer will suggest kanji(characters) based on what sounds you typed"
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6hq18w | Why are cologne commercials abstract and nonsensical? | Repost | explainlikeimfive | {
"a_id": [
"dj08lfq",
"dj0adhh",
"dj0jyq9",
"dj08gak"
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"text": [
"they're advertizing something that cant actually be conveyed electronically yet (maybe smell-TV will happen someday), so their choices are limited to metaphors and abstractions or \"trust me dude, it makes you smell nice\"",
"You can't convey a smell visually, also high end perfumes are a lifstyle brand/luxury good. The commercials convey an aspirational or class level attitude.",
"Did you ask this question after watching that Jared Leto cologne commercial? Haha",
"I don't watch cologne commercials but I'm pretty sure old spice does it simply to be memorable. and it works, at least for me, because that's the only brand I know of that does this."
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|
6hq79l | How are old movies that looked crappy on screen now being sold in HD? | Repost | explainlikeimfive | {
"a_id": [
"dj09r82"
],
"text": [
"As I understand it; - Old films were filmed using Film (funny, it's in the name): Film being an extremely high resolution (but it varies with different grades and types of film etc). - Those old films were originally digitized onto tapes etc for broadcast on a standard composite signal (CVBS), for TV and Tape. So its resolution/quality became limited by that medium. - By returning to the actual Film, and re-digitizing to today's standards (as the information/quality is actually there for a higher resolution within the film itself) a higher quality of the film can be produced and released. There are all sorts of caveats to this process, including the lossy nature of film (it degrades over time, and it costs a pretty penny to keep these stored in the appropriate manner for these studios) as well as losses in the process, etc. A lot of digital 'fixing' has to be done. I think this process is called re-mastering."
],
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|
6hqho6 | Why is gold valuable? Also, why was gold important to ancient civilizations? | I know it has good conduction properties and doesn't deteriorate, but there are other similar elements. Why was it important for ancient civilizations, especially ones that didn't use currency? | Repost | explainlikeimfive | {
"a_id": [
"dj0cbrb",
"dj0c9vh"
],
"text": [
"It's shiny, doesn't oxidize, yellow is rather unique as metallic color. It's also relatively soft and malleable with a low melting point (for a metal) that makes it a pretty nice material to work with and create art/religious symbols and being not that common makes it special, too.",
"For one, it looks pretty good. Most metals, if I'm not too mistaken, either look gray - in various shades, but ultimately gray - or reddish, like copper. Gold looks...well, gold. It's somewhat unique in that regard, as far as metals that won't harm you go. Two, \"doesn't deteriorate\" doesn't even begin to describe gold. Gold is incredibly durable after being amalgamated with relatively small amounts of other metal (such as silver), with the raw form being quite malleable, but when amalgamated, it'll outlast pretty much anything. This made it incredibly valuable as a method of storing value (what we call currency) and showing off wealth, at the same time. I think this answers the \"civilisations which did not use currency\" bit - even if you do not use currency, as in coinage or other methods, you will most likely need to store the value of otherwise perishable goods. Gold is one of the most un-perishable good you'll ever find. It's by no means a complete explanation, and I hope more knowledgeable people will elaborate further and correct errors I've made."
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6hr8gd | Why can't you measure position and velocity at the same time? | Repost | explainlikeimfive | {
"a_id": [
"dj0itbx",
"dj0l5y1",
"dj0obrc",
"dj0o1vq"
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"text": [
"Are you asking about the [uncertainty principle]( URL_0 )? This is only relevant for particle position and velocity. Everyday objects can easily have their position and velocity measured, since the margin of error that's acceptable for these objects is going to fall within the uncertainty limit.",
"This only applies to subatomic particles. The most common way to observe something is by looking at it. This boils down to bouncing photons (the particles of light) off of an object, and into your eye. For ELI5's sake, let's imagine that the subatomic particle you're observing is relatively the size of a beachball. The problem is, the particle is so small that bouncing a photon (or electron) off of it is like throwing a volleyball at it. When it bounces off, it's going to cause the beachball to move, even if just a little bit. Because of this, there is no way of observing without affecting its position.",
"Imagine you're looking for a ping pong ball endlessly bouncing around a dark room. You can feel around for it and find its exact position, but as you feel around for it, you'll hit it and change it's velocity. You could also stay quiet and listen for the sound it makes when hitting a wall to measure it's velocity, but that only gives you a rough idea about position. It's sort of like that; the act of measuring one changes the other.",
"A free particle travels as a wave of probability. The wave of probality is a [wavepacket]( URL_0 ) structure. To create a wavepacket requires adding different wavelengths together to form a location spike. The wavelength is related to momentum. When the wave packet collapses the particle has a position and momentum based on the wave probability. To make the wave packet more confined(high location certainty) requires adding a greater range (uncertain momentum) of wavelengths. The opposite is true too, fewer range of wavelengths means the wavepacket spreads out."
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6hrlhq | Why do we open our mouth / stick tongue out when doing work that requires precision like threading a needle? | Repost | explainlikeimfive | {
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"There's a few theories on this, to even include one adopted from your infant stage. However, the one I agree with most is: Biting the tongue or opening your mouth locks down or relaxes motor functions in the head, giving your brain less diverted resources to concentrate on precision. This follows to your body going still and rigid except for the necessary appendages. For instance, when you're threading a needle as you mentioned, you move slower, sometimes even slightly jerky, without the rest of your body moving at all. Your brain has not only turned all of its attention to the task at hand, but it's trying to balance that with providing only a minimum amount of energy for the delicate task. This would also explain why many people need quiet at times like this, because your brain would prefer no outside distractions, as it has to divert energy to process the sounds."
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6hrls6 | Why can't we write Braille like the regular alphabets? | Why can't Braille dots be arranged in the shapes of regular alphabets? What difference does it make to have weird shapes representing every alphabet? | Repost | explainlikeimfive | {
"a_id": [
"dj0lxpi",
"dj0m93x",
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"Imagine trying to read the word \"Ill\" (other word for sick) in Braille. Not easy. Other characters that are easy to confuse: E and F, O and Q, X and K, U and V. The Braille alphabet is designed to avoid these confusions.",
"Find an old typewriter and some tracing paper in it. Remove the ink ribbon and put \"AA\" next to \"M\" or \"VV\" next to \"W\" or try to tell the difference between a \"Q\" and an \"O\" once someone has rubbed it a few times. Another reason is space. To do what you're suggesting takes 3-4 times the room it already does, which takes about twice the room regular fonts do.",
"The braille dots can be so arranged, but then that would be using a writing system designed for eyes, but by using fingers instead of eyes. It would be using the wrong tool for the job. The alphabet is optimized for reading with eyes and loses its advantages when read by finger. Therefore it's better to use a system that is designed for the fingers, even if it's difficult to read with the eyes."
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6hrtf7 | Why does it take forever for my phone to load a GIF when it can immediately play a higher quality video with sound? | This happens for me regardless if I'm connected to wifi or using data. | Repost | explainlikeimfive | {
"a_id": [
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"From my understanding it is because videos are compressed and GIFs are not. GIFs are literally just a whole lot of pictures that flash up sequentially, but if you look at each one individually you'll notice that large parts of each picture don't actually change from picture to picture (i.e. the background might be the same throughout). So a compressed video file recognises this and tells your video player that those parts don't need to change and so the amount of \"new\" information from frame to frame isn't anywhere near as much as in a GIF which treats every frame as entirely new information. Another way to look at it is through animation. If you make a crude animation on a flip book you have to draw everything on each single page and so there is a lot of information in your flip book. However hand drawn animation will use static backgrounds and you only need to redraw what is actually moving in the scene on each page (in this case your pages would need to be translucent so the background remains visible). For example in a shot from the Simpsons the couch may not move and so it is a static background so the animators just need to draw Homer's movements on a clear sheet and \"flip\" through them over the top of the static couch and background. At least that's how I understand it, someone with a much better understanding may be able to add to this and/or describe it more succinctly.",
"GIF is an ancient, and not very good format. Why it is still alive is a mystery to me. It was never designed to be used over network connections, which vary in speed and bandwidth. Modern video formats, like used by Youtube, are explicitly designed to start playing as quickly as possible.",
"GIF animation is optimised for cartoony animations in which many of the pixels (e.g. a white background) don't change. Because in photo-quality videos almost every pixel changes on every frame, the size balloons compared to, for example, an MPEG-video which is optimised for photo-quality imagery that changes more gradually.",
"Variety of reasons. The most important is that GIF lacks the more modern compression tech in video codecs, so it is a much larger file / takes a lot more bandwidth. It also doesn't have the hardware playback assistance that video codecs do, so it requires more CPU cycles (and battery, for mobile devices) to play back. That's actually why imgur started automatically converting gif files to mp4 video, several years ago: URL_0",
"Online videos are encoded at several \"bit rates\" (quality settings), and the video player is usually capable of switching between different bit rates on the fly. It starts with a low bit rate and tests the connection to see if it can switch up to better quality file. GIFs are encoded in a very simple way, one of the effects of this is that they are encoded at a constant, much higher \"bit rate\". It takes much longer to buffer enough frames to start the animation, and if the connection is slow, the browser just stops playing the gif to buffer again rather than switching down to a lower quality."
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6hs0za | Why does helium make your voice high? | Repost | explainlikeimfive | {
"a_id": [
"dj0p9i1",
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"text": [
"Your voice begins in your voice box, which scientists call the larynx. Your larynx contains your vocal cords. These two folded mucous membranes vibrate when air passes between them. These vibrations resonate throughout your throat, nasal passages, mouth, tongue, and lips to create the sounds you make when you speak. The air you breathe is made up mainly of nitrogen and oxygen. Helium is much less dense than regular air. That's why helium is used in balloons to make them float. Due to its lower density, sound travels over twice as fast through helium than it does regular air. When you breathe in helium, your voice travels much more quickly across your vocal cords. This results in the funny sounds you make when you talk after breathing helium. Some people think that the helium changes the pitch of your voice. In reality, however, your vocal cords vibrate at the same frequency. The helium actually affects the sound quality of your voice (its tone or timbre) by allowing sound to travel faster and thus change the resonances of your vocal tract by making it more responsive to high-frequency sounds. SOURCE: URL_0",
"From what I learnt, helium is less dense than air. So when you speak, the rate of helium going through you voice cord is higher than normal producing more vibration. More vibration mean higher frequency."
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6htsu7 | How can the USS Fitzgerald hit another huge vessel? | Repost | explainlikeimfive | {
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"dj1199c",
"dj11j8v"
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"text": [
"It's not a question of seeing each other so much as having the time to maneuver. Large ships don't really turn or stop on a dime. Sometimes there's a space issue as well if the water is shallow.",
"There will no doubt be an investigation to figure out what exactly happened. Like most similar incidents it will probably end up with blame for many people to go around and with the knowledge that lots of different things went wrong at once. Keep in mind that while these ships especially the container ship are really big and hard to overlook, they are also not very maneuverable. Ships don't really have anything like breaks the can only decelerate and make turns rather slowly compared to land vehicles. Especially the container ship is very far from nimble. Chances are that quite a few people really did screw up big time, but what exactly happened is going to take some time to figure out. To get a general idea of how such collisions can happen in general and not this specific case you might want to watch this old navy training video about the USS Frank E. Evans which got into the way of an Australian aircraft carrier. [I Relieve you Sir]( URL_0 )"
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6hum5p | Why is the 1-2-3 on the top row of a phone keypad but on the bottom row of a calculator? | Repost | explainlikeimfive | {
"a_id": [
"dj17zpd"
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"text": [
"the first phones with an actual keypad used it to match the old rotary phones, which had the lowest number first. calculators existed before that, and had already established the 7-8-9 on the top row"
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6huzxz | Why do companies and sellers always blur license plates? What am I going to do with that information? | Repost | explainlikeimfive | {
"a_id": [
"dj1csjj",
"dj1aswf"
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"text": [
"1. Seeing a license plate is very different from recording and publishing when and where it was. Enough photos and we could piece together the majority of people's lives allowing for burglars, stalkers, rapists, exes, even government to destroy someone's life. 1. There are people who will find license plates of cars with the same make and models as theirs from a different state, clone their license plate and then use the vehicle in criminal activity. More often than not, it is simple stuff that will never make it to the owner like parking violations, but sometimes it is more serious stuff. Not only does this unfairly put the owner in question, but it makes it significantly harder to catch the offender. 1. Common decency. Broadcasting anyone's personal information without their permission has long been reprehensible because you have no idea the unintended consequences that could follow. 1. Your own protection. STORY TIME! Recently there was a young man who decided to harass my eldest son. He made fake online identities, bought VOIP numbers, all the clever things that someone would do in order to evade identification. HOWEVER, he sent one photo from his work that had 3 license plates in the background and a Wendy's sign off in the distance. From that information, I was able to find his town and exact location he took the photo from. I found his name, his address, his parent's names, their phone numbers, his pastor's name and phone number and with enough digging that he was soliciting and distributing nude photos of underage girls. I don't even have access to any government resources and was able to do this. Imagine what the government can do! Now, I doubt you are distributing child pornography, but unless you implicitly trust the government, and everyone else who has internet skills, don't post license plate info. If you ever have another question about why to not post personal information, just ask your local H̶a̶c̶k̶e̶r IT specialist.",
"A license plate is known as personal info like passwords, you can get sued if you shared that information online without their permission. That is why they usually block it or blur it out"
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6hv0ad | How can a massive container ship collide with a giant navy destroyer in open water? | Repost | explainlikeimfive | {
"a_id": [
"dj1b1gf",
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"text": [
"A lot of people are asking that question currently. We do not know what happened. Remember that big container ships are designed to do long straight hauls and therefore have problems adjusting their speed or turning. When they get close to shore they get tugboats to help them but out at sea you need to just stay away from them as they have no way to avoid a collision. And the area involved here are one of the biggest shipping lanes in the world with several big container ships passing you. So if you want to cross the shipping lane you need to be very aware of all the other ships and time the crossing to be between two ships. We do not know what the circumstances was in this case. It may have been low viability, there may have been inexperienced or tired crew, they may have turned off their lantern and radar to operate stealthy as a navy destroyer might do in combat or exercise. The answer will come as more information is being uncovered.",
"[This comment]( URL_0 ) from a similar question gives the answer. In short: while their are rules, when maneuvering a huge heavy ship, a small error can be very hard to correct. > It's not so different from walking toward someone on the sidewalk where you both move left, then both move right—just in very slow motion, and with a louder crunch when you bump together."
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6hvhjx | How does a 550 ft. Navy destroyer run into a merchant ship 2x it's size? How many mistakes go into such an accident? | Repost | explainlikeimfive | {
"a_id": [
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"text": [
"I assume you're talking about the USS Fitzgerald. She is actually 505ft, just a note. I don't know what kind of tech is on the ships, but it did happen in the dead of night, where lookouts are less useful. The ships definitely both have radar though, and at least one of them should have executed evasive maneuvers. That said, radar isn't always perfect. If you've ever seen a real life radar screen, it's a clusterfuck in busy waters. Clouds show up, too. There are measures to remove them, but they aren't perfect No matter how disciplined a sailor is, they are still human. At night, it's dark and serotonin is released into the brain, reducing awareness. You can't light a bridge because then you won't be able to see outside, and your natural night vision will be shot. Based on the damage, it looks like ACX Crystal was trying to overtake the USS Fitzgerald on the starboard side, but there was a miscalculation in the course. If both ships followed the proper procedures for collision regulation, this is the only case I can think of that would result in that damage. Could be either helmsman's fault, or a radar operator. Ships take a long ass time to alter course. It's very possible someone noticed minutes in advance, but the ships were not maneuverable enough to make the necessary adjustments. It could have been a wrong order or a wrong report. I know of one case where a lookout reported a container vessel on the starboard side, but it was actually on the port side, so when the ship altered course to port, under the officer's command, the container vessel plowed into it. This is like a fifth hand story, so the details are fuzzy, but that's the gist of it."
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6hy7b9 | How does a U.S. Destroyer, a vessel equiped with advanced technological systems, that is supposed to engage in tactical naval warfare, collide with a cargo ship? | Repost | explainlikeimfive | {
"a_id": [
"dj23u5r",
"dj23nza"
],
"text": [
"Massive and systemic watch-keeping failure on the part of the Naval Vessel's crew. Heads are going to roll here. Court-martials, possibly criminal-negligence charges. There is no excuse for this. None. Navy Ships have multiple people in the pilot house, lookouts all over the ship, people in CIC monitoring surface contacts. State of the art computer processors crunching enough data to take down 10's of targets at mach speeds. Able to scan the environment with different radar systems. The Cargo ship had the right of way : > *Collision Regulations Rule 15: When two power-driven vessels are crossing, the vessel which has the other on the starboard side must give way and avoid crossing ahead of her.* Navy ships also are required to have other vessels standoff outside their respective exclusion zones, to avoid [shit like this]( URL_0 ) happening. It's a complete breakdown of every single navigational procedure.",
"I don't know if it's relevant this time, but a little over 16 years ago, the US Navy proved that distractions can cause disasters. In early 2001, a Los Angeles-class submarine conducted an emergency surfacing maneuver ... directly underneath a Japanese fishing boat. The ship sank, and 9 people onboard died, including 4 high school students. Courtesy the US Navy's \"Distinguished Visitor Embarkation\" program, [the $2.1 billion fast attack submarine was under the control of an oil company CEO and a freelance sports writer for the maneuver, as directed by the ship's captain.]( URL_0 ) EDIT: If you don't have a picture in your head of a sub surfacing in an emergency, [it looks like this]( URL_1 ). Imagine that submarine coming up directly underneath a boat and you have the right idea. Anyway, if something crazy like that can happen once, perhaps it can happen again..."
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"https://en.wikipedia.org/wiki/File:INTEL-COGNITIVE-Cole.jpg"
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"https://www.youtube.com/watch?v=eOqalX5FJ2c"
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6hysyw | what exactly is radiation? | Repost | explainlikeimfive | {
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"dj26ftr"
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"text": [
"Radiation is a broad term and the name stems from something seemingly invisible that affects something at a distance. If you're thinking of that scary stuff that gives you cancer, you're thinking of *ionizing radiation*. That is, radiation that is energetic enough to knock away electrons of molecules and atoms. This radiation can therefore destroy your DNA which can lead to nasty mutations and cancer. There are many types of ionizing radiation, and a distinction between directly and non-directly ionizing radiation is made. But it's all particles (protons, neutrons, electrons, photons, even small nuclei, you name it!) with enough energy to knock out electrons."
],
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|
6i02dn | Why/how does total sleep deprivation lead to death? | Repost | explainlikeimfive | {
"a_id": [
"dj2g18g",
"dj2heqt"
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"text": [
"There are many reasons. Sleep is important for the leveling of hormones. If one isn't allowed to sleep that regulation starts getting very screwed up. Which is bad Sleep gets rid of cortisol in the brain. Which is the stress neurotransmitter. If that is never removed the stress will cause increased heart rate. Increased blood pressure and then death. Along with a host of other things that the body does more efficiently whilst asleep and if it can't do those things then things get out of balance",
"Sleep allows your brain to flush out harmful chemicals that build up throughout the day. You don't want these to continue to build up. Not sure if they will kill you by themselves, but they will cause neurological problems, and couple that with the other changes your body goes through, you're not in a good spot. After a couple days of no sleep, you don't process glucose properly. Glucose is quick energy for your body. If you can't get enough glucose through eating, or if your body can't use the glucose (which is what diabetes does), your body will use other sources. It will burn fat, but too much fat burning can be toxic. Fat burning produces an acid called ketones, and a high amount of ketones can kill you. If you've ever heard of someone with flu-like symptoms going to the hospital and nearly dying or even dying because they were an undiagnosed diabetic, it's because they had severe diabetic ketoacidosis. Mild to severe ketoacidosis can happen in non-diabetics if their bodies burn too much fat over a period of time. Should you survive the fat burning, the next thing to go is protein. Your muscles are made of proteins, and your body doesn't particularly care which muscles it gets that protein from. Coming from skeletal muscles will make you weak, perhaps unable to do daily tasks. Coming from your heart? That's just plain dangerous. I'm not actually sure if your body stops processing glucose completely or if it's just extremely difficult, but many sleep-deprived people crave glucose. If your body can process glucose, but not very well, you will need to eat a lot of sugary/carbohydrate heavy foods to prevent fat and muscle burning. If you can't get it, then the bad things above happen. Your immune system also stops working as well as it should. I'm not sure if this just means you get sick more easily and have a harder time fighting off illness once you are sick, or if it can become so severe that you can actually die from a mild illness. And then your body temperature drops as well. It may be able to decrease to the point that it's no longer compatible life. Stress hormones like cortisol builds up throughout this process, from the beginning, and they can put more strain on your body. If none of these things by themselves kill you, you are still in pretty rough shape. We know the ketoacidosis can kill you by itself, and cannibalizing heart muscle is a terrible idea. But those can maybe be avoided. The combination of all these things may be enough to kill you. There are some arguments about whether a human has actually died from from sleep deprivation itself. That may be because the people studying it assign another cause listed above as primary cause of death, not the sleep deprivation itself. If you want to learn about how bad it can be, check out [fatal familial insomnia]( URL_0 ). Apparently, some people can last 18 months without adequate or any sleep."
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6i1ua3 | Why do humans need a large variety of different food types to receive all the essential nutrients, while other animals can seemingly do so off of relatively few different types of food? | Repost | explainlikeimfive | {
"a_id": [
"dj2uf72"
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"text": [
"You don't *have* to eat a large variety of foods. You just expect a very high quality of life."
],
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6i3gxf | Why does unplugging things like a computer or internet router and then plugging them back in, generally resolves most issues you may have had? | Repost | explainlikeimfive | {
"a_id": [
"dj37os8"
],
"text": [
"Many of such issues are machines metaphorically \"getting lost\". A computer or a router ended up in some state that was unexpected or poorly handled by developers, and there is no obvious, easy or possible way back out of it. Turning it off and on again is essentially getting it back to the starting point (which is why it's called \"reset\" or \"reboot\"). Since the thing is merely lost instead of being broken, it would then continue to work as it is supposed to."
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6i3prd | How are coding programs coded? | I'm currently self-learning how to code / program (Python) - but how are these different systems programmed in the first place? | Repost | explainlikeimfive | {
"a_id": [
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"text": [
"They use another programming language to code up that one. And they use another language to make *that* one. And it goes on further and further back, until at some point they're writing the first text based programming language by putting punch cards in a machine. But what reads the punch cards? Go further back and they're programming by flipping switches on a big room sized box. And what reads those switches? Go further back, and they've **hard coded** the programming language directly into the computer's construction, like, the specific connections between the vacuum tubes are the programming language. This, of course, a very, very simple programming language.",
"Today they would be mostly created in another programming language. C in particular is a starting point since it was designed specifically to be easy to impliment on a new platform. So how is C (or another language) created without using an existing compiler? By determining the assembly instructions (instructions specific to one type of CPU) that would that comprise it on paper, converting each of those instructions into the binary values used by the CPU (machine instructions) and then finally creating some kind of input with that data, for example cutting punch cards or fabricating a ROM chip. For example a C compiler might have a line that simply reads `i++`, meaning it increments a variable I call `i` by 1. If I wanted to convert that into assembly code for say a 6502 (a popular 8 bit CPU that was used in everything from the Apple II to the Nintendo Entertainment System) I can write `INC $05`, which is a convenient and fast instruction that will load the value on page 0, offset 5 of memory (the 6502 can access 256 pages of 256 bytes each for a total of 64KB), add 1 to that value and then save it all in just 5 cycles. On other types of CPU we would often have to use 3 seperate assembly instructions to load, increment and save the value so the 6502 is a real time saver here. Finally we want to convert that assembly instruction (that still looks sort of like english) into actual machine instructions that can be used by a 6502. There are actually 4 different INC instructions, depending on how we want to address memory. The one we used, where it didn't specify a page and instead implied the zero page, is instruction `$E6` (or 230 in decimal). This instruction requires 1 additional byte to be complete, the address offset which was `$05`. This means our line of code translates into machine code as the sequence `$E6 $05` (or `230 5` in decimal). Finally we want to put this into a computer somehow so we take a metal tool and punch out the appropriate holes (1110 0110 0000 0101) on a punchcard which is then fed into a computer. Creating computer programs in assembly code or machine code used to be very common. One of the most well known software companies on the planet, Microsoft, got started because its founders Bill Gates and Paul Allen where very good at hand writing extremely efficient programs like this in order to work on the very limit memory of early home computers. Microsoft's first major sale was a BASIC interpreter for the Altair 8800 (a computer they had never actually touched, they developed their program purely from the Altair specifications) and while Paul Allen was flying to MITS to demonstrate it for the first time he realized they hadn't written a bootloader (a small program used to get the machine started and load the program you wanted, in this case their BASIC interpreter). So on his tray table he wrote, translated into binary and then punched a program tape for the bootloader, all without a computer (laptops wouldn't exist for decades). It ran on the first time. To give you an idea what a program tape looks like, [here]( URL_0 ) is one copy of that BASIC interpreter, preserved at the Computer History Museum.",
"Modern compiler developers often use a process called 'bootstrapping' to allow the compiler to be writen in it's own language. For example, if you've designed a new language, let's call it 'Look', and you want to write a compiler for Look, then you can of course write that compiler in another language (C is a popular choice), but often it would be easier if the compiler was written in Look, because there may be usefull paradigms included in Look that are hard to emulate in C. In addition to that, if the Look compiler was written in Look, then any improvements you make to Look will also improve the compiler. Finally, it means that you only need to be an expert in Look to write a good Look compiler, instead of having to be an expert in both Look and C. Enter Bootstrapping. The idea here is that you write extremely minimal and simple compiler for a subset of Look (protoLook) in a different language (or in extreme cases you can even write the bytecode by hand). ProtoLook is too simple to be of much use for actual work (it would be too tedious since many commands are missing), but it is a complete language in the sense that you can write anything in protoLook, given enough time. Now that you can compile protoLook, you can write a compiler for protoLook in protoLook. At this point you don't need the other language any more, everything can be done in protoLook. Now that you have a running protoLook compiler, you can start adding extra features to the protoLook compiler. With every feature you add, protoLook gets a step closer to Look, and with every feature you add you extend the capabilities of the protoLook compiler which makes it easier and faster to add new, more complex features. Eventually you've added all the features you need and you end up with a full-fleged Look compiler written in Look. The language is bootstrapped.",
"You have to clarify your question a bit. If I understand you question, I think you mean, how does the programming language itself get programmed? Assuming that is what you're asking, I'll answer that. Basically it is programmed from another language, in this case it started being programmed using c, which is just another language. Before all of that even, you need to understand that computers are communicating using 1s and 0s. In the beginning we used punch cards with literal holes in them to represent 0s and 1s. Then we got assembly language where we decided we could call 101000 to jump to another command. And we shortened it to jmp, so now we could jump to another part of the program without remembering the long string of zeros. Later on, we got even more advanced, and we used that assembly language to program another language, where we could write short programs without worrying about that jump command. Now we have a language where we can use if statements, like if the temperature is less than 50, start the heater. Now we don't need to worry about the jump command at all. Essentially, we don't write many programs in assembly anymore. And even c, sometimes we replace with ones like python where it is easier to do things. But, keep in mind, making it easier to program, means you lose flexibility. So, if you wanted to do something that language doesn't support, you're SOL. Hope this helps."
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6i440m | How does 'mining' for cryptocurrencies work? | Repost | explainlikeimfive | {
"a_id": [
"dj3ef7o"
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"text": [
"Say you are working for a bank. You also have a savings account for in that bank. The bank hired you to keep track of what the bank is doing. So you do your job, record that Harry paid Sally $20, etc. You show your work to the other workers at the bank. The other workers at the bank check to see if you did your job well, you check the other workers at the bank. In exchange for your work, the bank adds money to your account. This is exactly how Bitcoin mining works. The \"mining\" process is administration work on keeping track of the transactions of Bitcoins. When other people in the network check your work, they agree that work has been done and award you more Bitcoin."
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6i5g51 | Why is tipping a prevalent practice? | Repost | explainlikeimfive | {
"a_id": [
"dj3mos6"
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"text": [
"American style tipping is a relic of the end of slavery. The wave of completely uneducated and largely unskilled former slaves that left the plantations as soon as they were able to did not immediately find work. Many of them subsisted on what little they could get by working for free in places that \"allowed\" them to beg for a tip after they had lifted and carried for the customer."
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6i7mfl | Why is fathers day celebrated on the same day in US/UK, but mother's day isn't? | Repost | explainlikeimfive | {
"a_id": [
"dj42p0x"
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"text": [
"The UK combined a religious holiday, \"Mothering Sunday\" that was part of Lent, where you would traditionally return to the church you grew up in (your mother church) with the holiday celebrating your mother. The US, being more protestant and not as tied to the liturgical calendar as Anglicans and Catholics does not heavily practice the traditions of Lent and did/does not practice \"Mothering Sunday\" much at all. So when the US was choosing a time on the calendar to set the holiday celebrating mothers they chose to not put it during the Easter celebrations and so moved it to a relatively quiet point after that."
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6i9r3g | Why are witnesses swearing an oath in court if they're gonna lie anyway? | Repost | explainlikeimfive | {
"a_id": [
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"text": [
"Legally, lying under oath is called perjury and it's a separate crime. If you purposefully give false testimony after swearing an oath you can be charged with perjury. Realistically, that almost never happens. One reason is that courts often can't be sure who is lying and trying to figure it out with certainty is nearly impossible. It's even harder to know whether a witness was actually lying or honestly mistaken. Another reason is that it's already hard enough to get people to come to court to testify. Most people don't want to do it and if they think there's a good chance they'll get charged with perjury for testifying, they'll try to avoid it even more. Courts also want lawyers to focus on the facts of the case and don't want them to spend a bunch of time trying to get the opposing party thrown in jail for telling a lie. The oath is still useful, though, because it marks your official testimony that you can't take back once said. If you say something when you're not under oath, you can always take it back and claim you were \"just kidding.\" If you testify under oath, you're stuck with what you said. tl;dr - The oath is useful to let the Court and witnesses know that testimony given under oath is official and can't be taken back. The state can also charge someone with perjury for lying under oath in extreme cases."
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6id901 | What's involved in remastering a film, song or game, and how does it work? | Repost | explainlikeimfive | {
"a_id": [
"dj5ayqz",
"dj5bhne"
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"text": [
"In music it means the original audio tapes (aka masters) were used during the production process. Because of advances in audio playback, noise reduction, mixing technology and digital conversion the results are generally superior to previous releases. This differs from a normal rerelease which simply uses an existing final mix (which can be decades old) to create the new release.",
"In games it can mean anything from simply rendering at a higher definition to give smoother lines to a complete revamp by adding new textures, remapping controls, and changing the lighting."
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6idfa5 | Why does the washing machine always say it's 1 minute left, but leave me hanging for at least 10 minutes? | Repost | explainlikeimfive | {
"a_id": [
"dj5c3wp"
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"text": [
"The timer is the optimum time for that particular wash, but there are a couple of instances that can throw off the timer. * Filling with water. When the washing machine is initially filling, it will admit some water, and then tumble slowly, stop, put water in, tumble slowly and so on. What it's waiting for is a fill level sensor inside the washing machine to register that the water is at a particular level. If you've put a big load into the machine, or a very absorbent load, such as towels, the clothes will soak up more of this water, and it'll have to go through more fill/tumble/fill cycles before this level is registered. And of course the flow rate of your water supply will have an impact. * Balancing Most modern washing machines have a bit of cleverness in them to try and prevent an out of balance load going crazy and shaking the machine to hell on high spin. They'll gradually spin the drum up, and monitor how out of balance the drum is, using [various methods]( URL_0 ) such as measuring the movement of the drum, or how much power the motor is using, or how the speed of the drum is changing (if it's out of balance, the drum will be going slow/fast/slow/fast/slow, as the heavy bit starts the uphill part of the rotation). If the machine detects this, it'll stop the spin, then slowly tumble the washing again in an attempt to redistribute it. It will keep doing this until it spins more smoothly, and then start ramping the speed up. Until it gets to that point, the timer is (effectively) getting no lower, because it's making no progress. Yet on every machine I've seen with a timer, the timer will keep counting down even if it's taking time balancing the load. * Spinning Some washing machines can detect the water coming out of clothes, so will know when the clothes are spun as dry as they can be. Naturally depending on the load, this will take varying times. In my experience by far the biggest factor that affects the timing will normally be the machine balancing the load though. This can take a long time for the machine to get right, and sometimes it'll never manage it, which is why occasionally if you had a big, heavy load, it'll sometimes appear to be a completed cycle, but the clothes will still be soaking wet. This is where the isolated spin program comes in handy. This is why you end up with varying times. The counter will count down whether or not the machine is making progress or is in one of the 'wait' periods like filling the machine, or balancing the load prior to spinning, and when it gets down to 1 minute, it'll sit there until the machine actually is finished. They use this logic because they, generally correctly, assume that most people won't time it down to the exact minute and will just come back sometime near when it's supposed to finish, so most won't encounter this quirk of behaviour."
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6ik98i | If monopolies are illegal in the US as per antitrust laws, how come there are cities that reportedly only have one ISP to choose from? | Repost | explainlikeimfive | {
"a_id": [
"dj6xj5z",
"dj78g71",
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"text": [
"Not all monopolies are illegal. For example, some industries have natural monopolies. This is actually very relevant to your question about Internet Service Providers. A natural monopoly essentially develops when startup costs or other barriers to entry in the industry (such as complex regulation) naturally make it very difficult or impossible for another company to enter the market and compete with the existing market player. It's not necessarily the case that the existing market player is trying to smother all competition, in some cases it is simply too expensive or too risky for others to enter the market and be profitable. It's extremely costly, complex, and time-consuming for a new ISP to enter the market or even for an existing ISP to expand to a new service area. It requires the ISP to deploy their own infrastructure—literally install cabling that goes directly to each individual customer's home (often costing hundreds of dollars per home). In many cases this may involve digging trenches (including through people's yards) as well as digging up sidewalks, digging up roads, working with local governments to gain access to easements, access to underground conduits or sewer/drain systems, access to telephone poles, etc. This is all extremely costly, time-consuming, and complex. There are also a lot of regulatory compliance issues to deal with as well. Unless you have billions of dollars in funding, it just isn't feasible to deploy a new network and lay new cabling to people's homes. It is possible in many cases for ISPs to receive government subsidies to help pay for some of the cost of deploying a new network or expanding service areas, but it's still not enough. You still need major investors or enormous capital to lay new cable. Ultimately, if it isn't profitable for another ISP to service a given area, they won't bother trying to a lay cable and deploy a new network there. The ISP also has to consider—how many people will actually switch over to our ISP if we service a given area? ... Can you imagine spending hundreds of dollars installing cabling to a home and then that home never subscribes to your ISP? That's a total loss and really makes it difficult to earn a return on your investment unless you're sure that your ISP is going to be able to break through the market and incentivize a ton of people to switch over. What some smaller ISPs have done to mitigate this problem is that they only bring fiber-to-the-curb (FTTC) or fiber-to-the-neighborhood (FTTN) and then they make subscribers pay an initial connection fee of like $300 or whatever to help pay for the cost of wiring fiber directly to their home. But obviously this makes it a lot more difficult to get customers to sign-up for your service and isn't necessarily going to make your service profitable. All it does it make sure that you only spend the time/money wiring up homes that have people who are committed to subscribing to your service. It's also worth noting that there has been some past controversy regarding and municipal broadband competition. Some towns/cities with natural ISP monopolies have proposed building municipally-sponsored broadband networks that would bring high-bandwidth internet connectivity to the home, usually at a competitive price. Many ISPs have lobbied against these proposals and blocked these types of municipal broadband projects from going ahead because essentially they are arguing that these local governments are abusing their government power/authority by interfering with the free market and giving the municipal broadband projects unfair access/funding/subsidies or other advantages which the existing ISP monopoly doesn't get to benefit from. ISPs have successfully stopped many of these projects from going ahead, but it's also worth noting that most of the same ISPs that are complaining receive enormous amounts of funding/subsidies from government(s) to help build out their own networks. TL;DR: It's usually not impossible for other ISPs to enter the market and compete... It's just that it's often very risky, time consuming, and prohibitively expensive to deploy new network infrastructure and lay new cable. The risk is often greater than the potential reward and in many cases it could take several years to become profitable even if the ISP manages to secure the necessary funding/capital to build the network and manages to incentivize a large percentage of homes to switch over and subscribe to their ISP.",
"There's a concept in economics called 'Controlled Monopolies' and 'Natural Monopolies'. For certain industries, it's impractical to have much competition. For example, your electricity comes from a company like Eversource or National Grid or something. Walk around your neighborhood and see what that running that business looks like: power lines everywhere, electrical boxes, meters, underground cabling, running a massive grid. Imagine if there was like 5 companies to choose from for electricity. And each of those companies uses their own power lines, boxes, meters, etc. It'll look pretty crazy outside with all them cables! Dangerous too! So the Government steps in and says: \"Hey, let's make a deal. I'll let you be a monopoly - but I get to cap your prices and regulate you. Everyone wins.\" This is a controlled monopoly. This happens with industries that require a *lot* of infrastructure: water utility, gas utility - and now with student loans. Internet requires a lot of infrastructure, so most cities rarely have competition among providers. Internet isn't exactly a utility (yet) so it's not yet government controlled, however - it's a *natural monopoly*. Just because you're the only one doing it and there's no competition doesn't make it illegal trust. It just means there's a high cost to enter the market, and there's a lot of risk, so it may not be worth it. Some cities actually have government/municipal internet as their main ISP - like Chattanooga. And my hometown, Albany NY, had(has) a free wifi network throughout the city - Albany FreeNet.",
"To do a quick synthesis of the great posts here, especially the one from /u/pythonpoole , the key to anti-monopoly laws in the US is that they are mostly about preventing the abuse of monopoly power, and less about barring monopolies outright. The law doesn't care if through the natural actions of the market there ends up being only a single sausage maker for the city of Weehawken. It does care if the Weekhawken sausage king tries to start a salad business and tells his current buyers that if they don't buy his salads, then he won't sell them his sausages."
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6il3w5 | Why does time seem to pass much faster when you get old ? | Repost | explainlikeimfive | {
"a_id": [
"dj71gvs",
"dj71zlr",
"dj735dk"
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"text": [
"When your 20.. 1 year of your life is 5%.. when your 50.. 1 year is 2%.. thats what i heard once from Dr Karl . On triple j",
"This is partially caused by the fact you do not encounter as many new things in your life. For example: the first time you take some route from A to B, you probably remember the entire route. If you take the same route more times after that, each time you remember less of it, since it is a repetition of the things you already know (everybody knows the feeling that they come home but cannot remember exactly how, or at least, they do not remember the entire way). So you store less of your encounters, in comparison to when you were younger, since a lot of things you see or do are similar to things you encountered earlier in life.",
"I always compare this to chapters and bookmarks in a novel. Everyone remembers when Dumbledore dies, but few people remember the conversations Harry had at the dining hall so many times and across so many novels. When we do not do interesting things in our lives we end up with big, hard to reference chapters. We sort memories by big events. Little things get remembered, but when you dredge them up from the depths of your mind there aren't much other things attached to it. The first part of our lives are full of memorable \"firsts\". First kiss, first drink, graduation, first time getting into a fight, etc... There are a ton of bookmarked and highlighted areas that we can review. New sensations and experiences that change us. Our brain itself is still changing so even the same event can be notable twice or more. And each event has a huge impact. A 50mb file is a huge amount of space on a 500mb hard drive. Later in life, your hard drive has grown to 500gb. That 50mb file is barely noticeable. Later on in life, especially if you live your life \"by the rules\", we end up with less of those. Sometimes there can be years between new and memorable events. Maybe a car crash here, a move across the country there... Everything in between sort of blurs together from all the empty space. We learn to integrate our experiences very easily. The second time moving across the country is just an inconvenience. The difference between \"Bookmark 340\" and \"Bookmark 341\" can be hundreds of \"pages\". Without milestones we lose our place \"in the book\". We just keep reading and only occasionally realize our eyes have been moving but we don't remember anything from the last 20 pages. An old man once told me, \"Why do most old people have regrets? **I've lived one year 74 times. Most people live one 74 year life.** It's easy to regret staying on the straight-and-narrow. What if this, what if that? I answered that question with action every time it came up. So... I never became a doctor, of course - Never real had the desire. But every old, retired doctor I've met wishes they spent a few years living like I do.\""
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6imgw2 | What is the difference between socialism and communism? | Repost | explainlikeimfive | {
"a_id": [
"dj7cpfk",
"dj7c04f"
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"text": [
"In socialism the cows belong to the government in communism the cows belonng to the people.",
"Generally, socialism is the belief that capital should be owned by the people/workers/government as group, rather than being owned by individuals or companies. Communism is a larger theory of history and economic development that predicts an ultimate end state of history where there are no longer economic classes (or government) and capital is held in common."
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