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6qi6bb | when amazon video offers to show me a 1968 movie in hd for $1 more, is there actually any difference in quality? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/6qi6bb/eli5_when_amazon_video_offers_to_show_me_a_1968/ | {
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"Sure.\n\nFilm in good condition is actually very high quality, better than HD. Quality was lost when SD media was made from it in the 1990s, so going back and making an HD version will result in a higher quality video.",
"Yes.\n\nIn fact, most movies from 1968 are higher in visual quality than most movies from the last decade. Anything above low-budget indie productions was shot on 35mm film, and high-budget movies were often shot on 70mm film. It's only pretty recently that we've had digital video cameras that can exceed 35mm quality and they're still not that common. There still isn't a digital video camera consistently exceeding 70mm quality. Digital filmmaking became popular in the 2000s, but not because it provided better image quality -- because it was cheaper, faster, and more convenient.\n\nThere are still a fair number of movies made on film, though it's decreasing each year. For example, *Star Wars: The Force Awakens*, *Jurassic World*, *SPECTRE*, and *The Dark Knight Rises* were all shot on film, and have roughly equal visual detail to a movie shot in the 1930s.\n\nMost video services mean either 1280x720 or 1920x1080 when they say HD. You can scan well-preserved film at 4-8 times those resolutions and still not capture the full detail present.\n",
"Remember that film is a chemical reaction to light. Film well on, well, film, and you can scale it up quite well as though you are viewing something through a microscope or other lens. The amount equates to 8K and is as such as high definition as is standard today for digital. Digital is basically assigning a pixel a colour based on the light that hit it and some math (basically to fill in the most common colour within that pixel). You can increase pixel density but you can't gain extra information once filmed so basically you are trapped at the highest resolution it was filmed at, otherwise its pixelated. "
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65r5xl | why does going outside to get some "fresh air" genuinely seem to help with headaches/feeling ill? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/65r5xl/eli5_why_does_going_outside_to_get_some_fresh_air/ | {
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"Many possible reasons, including psychological factors, but a big one is that, even in an urban area, indoor air can be up to ten times more polluted than outdoor air given conventional ventilation and latently toxic building and finishing materials. \n",
"Poor indoor climate has a huge effect so actually getting fresh air helps. Stepping out in nature opposed to walking around a really poluted place like Times Square also helps as the air is actually 'fresh'. Also oxygen. Oxygens helps relieve headaches. \nIf you suffer from bad headaches (like really bad) then you can actually go to the ER and get oxygen which helps. Don't know why though. ",
"It may be that removing yourself from a stressful situation helps more than the air your breathing",
"As others have said, when you're inside a building/room for a long time, and there's little/no air circulation, the air can become a little 'stale', per se, with dust or other things getting into the air. Stepping outside allows you to breathe in some fresher air with less pollutants in it. (hopefully)\n\nIn terms of nausea, I've found that breathing in cold air tends to slightly alleviate nausea, and on top of that, if you take deep breaths in through your nose and out through your mouth, that also alleviates nausea, so both of those combined would certainly have a strong effect.\n\nThe placebo effect could also be working in there. You believe that the air outside is fresher, and that causes it to have a positive effect on you.",
"On the most recent CBC Quirks and Quarks podcast, they were talking about how in tall buildings there can be movement that can give some people headaches. Plus the indoor air quality reasons everyone else mentioned.",
"You may have headaches from staring at the computer screen close to you, and going outside lets you look into the distance and relax your accommodation (basically giving the tiny muscles that move your eye lens to focus up close a break)",
"Relevant wiki links:\n\n[Sick building syndrome](_URL_0_) \n\n[Indoor air quality](_URL_1_) \n\nHope these help! These pages were really informative when I was researching plants to add to my office to improve air quality recently. \nBasically comes down to indoor air doesn't cycle through with fresh air frequently enough and allows for the buildup of not-so-nice chemicals, mold spores, and other respiratory tract irritants.",
"There are a wide range of indoor air quality problems that could be causing your headaches.\n\n > DO you have a sore throat, runny nose or watery, itchy eyes? Are you sneezing, coughing or wheezing? Does your head ache? Feeling tired and irritable? You may have picked up a bug from a friend, family member or co-worker. Or you may have gotten sick from your house.\n\n > ''People usually attribute these symptoms to a cold or a flu,'' said Andrew Port, director of indoor air quality for Environmental Waste Management Associates, a consulting company in Parsippany, N.J. ''But in a significant number of cases, these symptoms are indicative of either a problem with their heating, ventilation or air-conditioning system, or the presence of elevated concentrations of indoor air pollutants.''\n\n_URL_0_\n\nYou may want to keep some windows open to air out your house. During the winter, I always open up doors and windows for about 20 minutes a few times a week. During the summer, I like to keep the air flowing throughout the house all day and night because I am also sensitive to mold, dust, and fumes from things like furniture. ",
"It could be that you are getting away from an indoor carbon monoxide source. The headaches might be a sign of carbon monoxide toxicity.",
"Not a doctor or anything, but I'd imagine a lot of it has to do with change of environment. You are changing your body position and relieving some physical stress from being in the same position for a few hours; psychological stress relief - you are taking a break from work stress; ocular relief - not looking at a screen, change of air quality. ",
"A little late but while indoor air may be a factor, walking is enough physical activity to get your blood moving oxygen a lot better.\n\nFuck the science, just use your body and you feel better. I get chronic migraines and sometimes I just go for a run. It'll take about an hour before I feel better but it's better than rolling around in bed, in pain all night. ",
"This is not going to give you the full answer but just understand it is part of the greater answer. Also it is more ELI 10 or ELI 12 than ELI 5\n\n\nWe often associate negative feelings with fear but understand fear is a complex feeling that can be made out of basic feelings of different types.\n\nIf we want to go basic feeling two primal / more basic ways of describing fear is.\n\n* I do not like it for it is disgusting. **It is ICKY**, it taste bad and I stick out my tongue and throw it up or spit it out.\n\n* I do not like it for it is uncomfortable. It hurts, it is not pleasant, it is abrasive, it not fun, it is rough, it is frustrating. **It is IRRITATING, IT MAKES ME MAD**, *note mad is not the same as Angry or Rage in this sentence.*\n\n* I do not like it for it is uncertain and the uncertainty can lead to quick bodily injury. **It is SCARY.** It is monster in dark closet, under bed, it is too intense.\n\nNow there are different ways fear can have different origins, fear can be caused by Anger, Sadness, Joy and Loss of Future Joy, plus lots of other things. Note there are different models of what is the most core basic emotions and what are more complicated emotions and what are feelings which are more complicated emotions that is supposed to convey state of change information and so on.\n\nWell the 3 bullet points I said, 1) It is Icky, 2) It is Irritating / It makes me Mad and 3) It is Scary have different things your body does to change the stimuli.\n\n* Usually Icky stuff that involve disgust requires some form of purge and it is caused by sensory confusion / overwhelming sensory information and your body assumes emptying the digestive system will fix it. Changing the sensory environment from the unpleasant icky sensation to a more pleasant lesser form or just stopping the icky sensation tells your body you can stop purging the digestive system and stop producing nausea, dizzyness, light headed, etc.\n\n* Usually Irritating / Makes me Mad / Uncomfortable Sensations is telling your body that this is not the correct way with touch but it can also be other sensory based like sound and auditory, visual, chemical / taste / smell, and your body needs to change but it is not necessary bad or good but just improper in its current form. For example Irritation can become Good Forms of touch if you change where the touch lands, or where the pressure is being applied, or changing the form in some way. Note this system is not just a negative system we now know many of the same brain areas are involved with making something bad into something good / great. For example a massage is often very pleasant or very improperly done and it hurts or is uncomfortable.\n\n* I do not Like it for it is SCAREY is a similar system as number 2 but also different. It is either too intense, or too unpredictible and it scares you. Now this can be new information or it is suddenly changing so fast that unexpected things that are bad with long term consquences including death, injury, but just not knowing what is going to happen next may occur. For example sensory information of a sharp pain like a knife travels faster and uses different sensory pain receptors on the skin as slower pains like blunt force pain. But it is also used for other things, for example to a 3 year old SCAREY as in sharp pain is the same feeling they will experience with separation anxiety from mother if they are a person who becomes scared if the mother is not in eyesight or other sensory modalities and the baby has had a traumatic past or the mother is too unpredictable and there is no other caregiver like a father or other thing that makes a baby feel comfortable. Not with older ages many of these temporal uncertantity will change and these types of stimuli may be less scarey but still exist. For example a sudden change in reversal of fortune may feel like a sharpe extreme fear as in scarey but a more prolong sense of dread may feel differently than the sharp it just happened feeling.\n\n & nbsp;\n\n & nbsp;\n\nSo long words so far I doubt a 5 year old can keep this attention and the 10 or 12 year old would still have problems.\n\nBut in interoception information, sensory awareness from internal bodily states like how does it feel to me it is changing me, vs it is changing my enviroment are handled by different brain areas. Now it is not a single brain area but collection of brain areas and some of the outside sensory information vs it afectts me like touch have some brain areas in common.\n\nBut interoception sensory data involves the insula and it is integrating multiple sensory information in the insula and other brain areas. By changing the stimuli and introducing stimuli that is non threatening it can upgrade or downgrade the actual raw sensory data and change the intensity level.\n\nFor example you may still be nauseous but you are no longer overwhelmingly feel nauseous for I now have more sensory information to know if I am stable or not.\n\nNow some of those sensory feelings of fear I describe earlier, Disgust, Irritance, Terror / Scarey have different ways your brain takes in information and figures are you in a stable information or not. For example deep breathing will fix disgust often, but it will not fix irritance and it will have limited effects on terror or scarey. Changing the type of touch, aka moving can reduce irritancy. Terror / Scarey but also the positive versions of this like sudden windfall and the high of success has to do with the predictability of the stimuli and also the amount of times the predictability occurs over time. (Aka can I understand it, and does it happen often or not.)\n\nThus why does it fix it depend on what are you trying to fix? Different types of fear and sensory information / confusion needs different fixes but often it can be fixed where turbulent emotions / sensory data / feelings can be calmed and steadied but how you do so may be different as a stabilizing force."
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5h7wvd | how to wirelessly project my computer screen onto a tv? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5h7wvd/eli5_how_to_wirelessly_project_my_computer_screen/ | {
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"As u/CptCreosote said, Plex is probably the way to go. I wanted to add to that. This is service software that should run on a dedicated media PC you can designate as your media server. Congratulations, you're in the IT business now. I'm not saying it's hard to setup or anything, I actually want to comment on WiFi bandwidth.\n\nYou see, each device can only transmit or receive at a time; WiFi is thus half-duplex. If you think you're going to run this from your laptop, over WiFi, to your Chromecast, over WiFi, you're going to have a bad time, because your laptop has to send data over the air to the router, which then needs to send it over the air to the Chromecast. That's twice the airwaves for once the show, if you get my meaning. Bandwidth is going to go to shit, especially for everyone else also trying to use your home network, and your media experience will suffer terribly, may be even unwatchable maybe unless you drop video quality down to shit.\n\nSo what you want to do is host Plex and your media on a computer that is physically wired to your home router. You won't be using WiFi to move data to the middle man, the router, before transmitting via WiFi to the Chromecast. Your casting experience will be as you expect it, and you may even be able to do some casual browsing while the movie is playing."
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5ulwoj | why does music sound slower when i'm sick? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5ulwoj/eli5_why_does_music_sound_slower_when_im_sick/ | {
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"Your body temperature can deregulate your internal clock.\n\nQuoting [PubMed](_URL_0_):\n\n > Experiments investigating timing behaviour in humans under conditions where body temperature was raised or (much more rarely) lowered, dating from 1927 to 1993, were reviewed. These tested the hypothesis that humans possess a temperature-sensitive chemical or biological internal clock. Most studies used conditions in which subjects produced or estimated durations less than 100 sec long, probably using chronometric counting, but other experimental paradigms were sometimes employed. Data from each study were expressed in a uniform fashion, as plots of changes in the rate of subjective time (estimated from changes in timing behaviour) against changes in body temperature. In almost all cases, rate of subjective time increased when body temperature increased above normal, and decreased when body temperature was lowered below normal, although observations of the latter type were rare. The data also suggested a parametric effect of body temperature, with higher temperatures generally producing faster subjective time. Some possible mechanisms for the effects obtained were discussed, with the most promising explanation probably being that the temperature manipulation produces changes in arousal.",
"Out of curiosity, do you usually hear those songs on the radio but was listening to them from the album or streaming on the bus? Music on the radio is pitched faster to appear more upbeat to compete with other stations and to give a more \"fresh\" impression. "
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6m2nsr | would a cannonball splash save me from dying at a high enough altitude into the water? | I understand that water at high altitude becomes something like asphalt and if i were to fall on it, i would surely die, if i curled midway and protected myself with my arma and legs, would i survive? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/6m2nsr/eli5_would_a_cannonball_splash_save_me_from_dying/ | {
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"i think youd have a better chance if you go in feet first, toes pointed, with your legs tightly together, arms tightly at your sides. with your ass clenched tight. you want to pierce the surface of the water like a needle. ",
"Well, aside from the part where you'd have to time it perfectly (and you couldn't let it go while you were freefalling), the effect of breaking the surface tension is marginal at best. \n\nAs someone else mentioned, the pencil dive formation is the best choice. Your legs might break, but you'll live. And getting into that formation is easier than you'd think; it isn't that hard to change your position during a free fall. First, you get into the fall position that parachuters use, then you transition into the pencil about 100 feet above the water.",
"TL;DR: Absolutely not. Your best bet is to hit feet first, arms tucked in and appropriate holes clenched.\n\nA big part of what kills you on water impact is deceleration trauma. How fast you decelerate in the water is directly connected to the overall length of what's entering the water; a long, narrow object penetrates deeper below the surface and decelerates at a lower speed, while a bunched up object comes to a dead halt much faster. Additionally, when you're all curled up in a ball, there's much less 'you' between your head and vital organs and the surface of the water; as gross as this likely sounds, but in a feet-down entry your feet, shins, knees and thighbones act as a crunchy \"crumple zone\" protecting your intestines and points north. It's probably a moot point if you're falling far enough to shatter bone on impact, but it could make the difference between the ER and the morgue. \n\nAnother big part of what kills you on water impact is disorientation. Between the pain, panic and trauma people get scrambled about, lose their sense of where the surface of the water is, and proceed to swim the wrong way until they black out. Adding to the problem, if you spin or rotate on the way down or after water entry, the fluids in your inner ear can start moving in non-helpful ways, making your own body tell you the wrong way to go. Hit the water feet first, and you improve your odds of being able to process which way is up in time to make a difference. Hit it in cannonball mode, and who knows which way you're going to be facing, and what the fluid in your inner ear is going to be telling you. \n\nAs far as the clenching, that's mostly to keep high speed water from rushing in somewhere it shouldn't, an incredibly painful insult on top of injury that could further compromise your survival chances. "
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atcf5o | how can the color spectrum be wrapped into a continuous color wheel? how can the highest frequency colors blend into the lowest frequency colors without clashing? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/atcf5o/eli5_how_can_the_color_spectrum_be_wrapped_into_a/ | {
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"The spectrum is continuous, but our eyes sense three (overlapping) colour bands: red, green and blue. Objects emitting red and blue light, but little green light will appear to us as magenta/purple. The colour wheel is a construct based on our eye's three colour sensors.",
"Because our eyes only detect three colours of light: red, green, and blue.\n\nWhen both red and blue light reaches our eyes but not green, we perceive it as magenta (a bright pinkish purple color).\n\nWhen both red and green light reaches out eyes but not blue, we perceive it as yellow - but what is interesting is that things that reflect *yellow light* will stimulate both our red and green receptors as well (just not *as much* for the red receptor as red light would) so yellow light also stimulates the red and green detectors, hence why it looks yellow.\n\nIn short, there are two ways to see yellow - from actual yellow light (which is between the wavelengths most detected by the red and the green receptors) and also from a little bit of red light and a little bit of green light both being detected at the same time.\n\nBut there is only one way to detect magenta, since there's no magenta wavelength! The wavelength between red and blue is just the green wavelength, but if you are detecting both red and blue but *not* green, it can't be a really bright green spilling into red and blue! So it must be something else. As such, our minds blend the colours smoothly as we add or remove various amounts of each colour, and this necessitates a ring-like structure.",
"Because we don’t perceive color as a linear spectrum, but in ratios of how much they excite our 3 different types of photo receptors. As wavelengths get shorter, color goes essentially from red towards blue. Where purple/magenta come in is when the receptors at the high and low ends of the spectrum are triggered but not the ones in the middle. This is how the color spectrum we perceive is able to wrap around on itself. ",
"I heard Boxer Shrimp can see like thousands colors that us humans cannot see. What would happen to a human if they could suddenly see all the spectrums?",
"The short answer is that they don't. Spectral colors are those made by pure wavelengths, for example a laser: _URL_0_ In the picture there it's an edge of a color space. Everything else can only be made from a blend of wavelengths.\n\nThe color wheel is by blending the 3 primary colorants, whether they are pigment (subtractive, traditionally RBY, now CMY) or light (additive RGB).\n\nIt's like trying to put noise into a musical scale. What single note is a cymbal crash? They're different kinds of sound and thinking about something general into something specific doesn't work. In the case of color wheel vs spectrum, they're two specific treatments of something more general, called color space.\n\nConfused already? Impossible colors exist too: _URL_1_ \"supposed colors that cannot be perceived in normal seeing of light that is a combination of various intensities of the various frequencies of visible light, but are reported to be seen in special circumstances.\"",
"Copying my reply to someone else, since some have appreciated it's ELI5-ness:\n\n \n\n\nOk pretend you have red, blue, and green applesauce cups. Your job is to sort them out by color. The only colors you know what to do with are those three, because that's all your line can produce. This is like your eyes only having those three colors of receptors.\n\n \n\n\nEveryone knows there's no such thing as a magenta apple, but one day, the blue and red apple sauce cups fall off the line and bust open, mixing together. It's still in a clean, sterile location and you don't want to lose your job by tossing good product. So, to avoid trouble, you make a new line for the magenta applesauce and call it a seasonal item.\n\n \n\n\nYou're making magenta applesauce even though it doesn't exist on its own, just by mixing the two and labeling it as something. That's what the brain does. It makes sense of the two receptors being active by blending them the best it can, even if it's in a wavelength that technically doesn't exist.",
"My favorite explanation:\n\nIn music, sound waves go through a scale. You can play a C note, then D, E, F, G, A, B, C. When you get to the C again, you've reached an octave.\n\nOctaves have a consistent sound to them because the two notes are creating sound waves that are exactly double/half the frequency of each other. In fact, playing one note actually causes the other matching notes to vibrate because the sound waves compliment each other.\n\nNow, the same thing happens with color, since light behaves like a wave. We have red, green, and violet cones that help up perceive the color spectrum. However, light waves on the deep red side, as they approach infrared, start complimenting the violet wavelengths, essentially creating a color \"octave\". That stimulates our violet cones, so we see a color that's an imaginary blend of red and violet. The same thing happens on the other end with colors that are approaching ultraviolet starting to stimulate our red cones.\n\nEdit: Here's a much more detailed explanation of this: [Link](_URL_0_) ",
"Because it's hard for the human eye to tell the difference between violet (true violet, shorter than blue wavelengths) and purple (blue with some red mixed in) and so by going from blue to purple to magenta you can get back to red.",
"The top comment is great, and correct. But I’ll try to do an even simpler version:\n\nThe rainbow you see in school, with red at low frequencies and purple at higher, isn’t wrong. But it’s not enough. It’s missing an obvious thing that even a child will ask: what is “white?”\n\nWell, white is every color together. Our brain perceives every color together as a color of its own. Okay, fine. But what if I take out blue? What if I show you every color together except blue? What color is that? “Not-blue-white-ish” isn’t a thing.\n\nIt turns out that your brain simply invents another color for this, and it’s something like “bright pink.” A color that doesn’t exist anywhere on the original rainbow, by the way! But is definitely a thing!\n\nThe way your brain *perceives* these combos of color, or lack of colors, is what ends up making a circle.",
"OK all the answers so far seem to be missing a critical element:\n\nOur eyes' red receptors are meant to detect red light (lowest wavelength, let's say 700-600 nm) but due to their chemistry, they also respond to the ~~first harmonic -- at half of that wavelength~~ much shorter wavelength at the far-end of our vision.\n\nThis means that if the light is ~~half-of-red-wavelength (which is~~ above blue ~~-- it's not exactly precise)~~, the red receptors start responding to it again. Blue receptors also respond and what you see is a combination of \"fake red\" and blue -- a colour we'd call violet. Obviously indistinguishable from an actual mix of real-red and blue.\n\nThis is what causes the wrap-around point.\n\nBTW, if your eye didn't filter UV at half-of-green-wavelength, you *would* see it as green, for the same reason (but not for long, your eyes would burn down very quickly)",
"The answer is disappointing:\n\nWe don't actually see the colours that things are, we see what our receptors notice.\n\nReceptors are quite limited and so each only sees a colour range around roughly 3 colours (440nm, 540nm and 580nm), though supposedly some people have partial reception of a fourth and some only two, the latter is a form of colour blindness (other forms of colourblindness involve shifts of sensative wavelengths or reduced response)\n\nBecause every colour we percieve is actually just a mixture of three colours, you can create a gradient between each of them just like you would while mixing dyes; shifting the relative amounts of each response and leading to combinations. \n\nAs an example: we don't see yellow, yellow is a mixture of our response to a bluey green called Cyan and Red.\n\nIt's hard to articulate, but simply put, percieved colour and the colour scale is an accidental result of combinations and partial activation of very specifically sensitive cells.",
"It's a simple side effect of the fact that the number of color components is 3. ",
"Many of the answers here are inaccurate. I'm not sure I can really explain it well but I'll try.\n\nThe important thing to understand is that vision doesn't start with the spectrum, it starts with the three types of cones. Spectral colors don't matter evolutionarily. There is no benefit to seeing a rainbow in any particular way. Colors are for recognizing ripe fruit and predators and such, and our color perception is adapted to that. The colors we see in the spectrum are a side effect of color vision that evolved for more mundane purposes. That's why they look so arbitrary and nonuniform.\n\nNot only does the spectrum not matter, evolution doesn't \"understand\" frequencies of light at all. We have three different pigments that are sensitive to different frequency ranges, but the pigments don't know what they're detecting and the later stages of the visual system don't know what the signals they emit mean. All the visual system really knows is that the color information from the eye is \"three-dimensional.\" Within the brain, those three dimensions are interpreted as light-dark, red-green, and yellow-blue. The red-green and yellow-blue pairs suppress each other (the [\"opponent process\"](_URL_0_)), meaning that you normally can't see a mixture of red and green or of yellow and blue. But all other mixtures are possible: red with yellow, yellow with green, green with blue, blue with red. If you see similar amounts of red and yellow, you see orange. If you see similar amounts of red and blue, you see magenta, and so on. That's where the hue wheel comes from.\n\nEvery part of the hue wheel is equally real, or equally imaginary I suppose. Every hue can be produced by real light striking the retina. It happens that not all hues can be produced by *monochromatic* light striking the retina, but that doesn't matter because monochromatic light rarely occurs in nature.\n\n(Edit: linked wrong article)",
"**ELI5:** The wheel itself is an artistic invention based on how we perceive color that makes it easier to identify opposing or correlated colors. It's more (scientifically) correct to arrange colors in a line with red at one end and purple at the other. However, other shapes also exist for different purposes:\n\n_URL_0_\n\nFor more details, check with a physics teacher, this is the stuff they love to go on fun rants about.\n\n----\n\n**ELI > 5:** The short answer: it can't. The color wheel itself doesn't exist in a scientifically meaningful sense: the purples don't blend into the reds, we just have time differentiating then at extremes because they're going outside of the visible spectrum (effectively fading to black).\n\nA more correct representation of the color wheel is the color line where purple and red sit at opposite ends. That more correctly reflects the different wavelengths of light that make up the colors (about 700-400 nm, iirc). You can experience colors outside the color wheel pretty easily: infrared light is redder than red and feels like heat, like you would get from a heat lamp. Ultraviolet light is purpler than purple, and is what causes sunburns when you're outside or sun tans in a tanning booth.\n\nThe wheel itself is an artistic invention based on how we perceive color that makes it easier to identify opposing or correlated colors.",
"Short answer: It doesn't.\n\nLong answer: The color wheel does not display the real spectrum of light, but rather, our visual gamut.\n\nOur eyes do simply receive light and send a signal of what the light's wavelength is to our brain. It would require too much junk in our eyes to leave room for a crisp picture, and contain too much information for our brains to process in a reasonable time.\n\nInstead, we've evolved with 4 specialized types of visual receptors. Three types of cones, and one type of rod. The rod simply detects the energy of the light they receive, and send a brightness signal. In effect, these rods detect any kind of light between about 400 to 600 nanometers(though they peak at a wavelenth of 498 nanometers, which is between green and blue) and interpret it as a color agnostic lightness of what we're seeing. These however, mostly function for vision in low-light conditions.\n\nThe cones come in 3 flavors - S, M, and L or short wavelength, medium wavelength, and long wavelength. The long cones peak at 564 nanometers, but react to a range of about 400 to 680 nanometers. The mediums peak at 534 nanometers, but react to a range of about 400 to 650 nanometers. The shorts peak at 420 naometers, but react to a range of about 370 to 530 nanometers. \n\nBasically, these cones detect the redness, greenness, and blueness of light. If a wavelenth of 580 hits your eyes, it excites both the long and medium cones a decent amount, but not the short cones, and you see yellow. But if 560 and 600 hit at the same time, you see the same yellow as the 580 wavelength light, because the average effect of the two colors of light equals 580. This is called the trichromatic theory of vision, and it explains how we can see so many colors with so few types of photoreceptors.\n\nBut, it's not as simple as sending four images that your brain composites. That's still too much information. Instead, the cones and rods are wired together in such a way that they compare their results in order for your optic nerves to figure out what colors are actually being seen. Firstly, the signals from the L and M cones are compared, and the one with the highest signal wins. And how much it wins by determines how much red or green is seen.\n\nAn example: if an L cone is excited 80%, and an M cone is excited 20%, the two signals are compared. We'll assign a negative sign to the L cone, and a positive one to the M cone. -.8 + .2 is -.6, so that *color circuit* will register as a -.6, or 60% redness.\n\nThen, the L and M signals are averaged together, and compared against the S signal. The same things is done as before to find the blueness or yellowness of the image. We'll assign the (L+M)/2 signal a negative sign, and compare it to blue. Say we have the same 80%, 60% signal as before which averages to 70%, alongside a 40% S signal. We get -.7 + .4, and that leaves us with -.3, or 30% **yellow**. So now we know the light in this region of the eye is 60% as red as it can be, and 30% as yellow it can be. It would seem we're seeing a dull, dingy, orange, nearly grey color.\n\nBut there's one more step. We now average all three signals together. .8 + .6 + .4 = 1.8, which divided by 3 is .6, so it's about 60% as bright as it can be.\n\nWe now have the signal we send to the brain. g*-.6 + b*-.3 + l*.6, or \"negative 60% green, negative 30% blue, 60% bright\". Something being \"negative green\" is red, and something being \"negative blue\" is yellow. And that, actually, explains why you've never seen a red-green color, or a blue-yellow color. The signal isn't ACTUALLY something quite like that, but this represents what we need for purposes of understanding this just fine. *AND* we've also just learned about this \"opposing circuit theory\" of vision.\n\nWhat's this have to do with the color wheel, and why it wraps around? We'll, you may have noticed that seeing a blue and red light at the same time, both irl and in this system, doesn't average into green like how blue and green average into cyan. Red to green and green to red have corresponding wavelengths connecting them, but red to blue does not. But you've encountered, in real life, things which are both blue and red, but not green. So to solve this, your brain invented a color - Purple.\n\nIf you recall Isaac Newton's \"seven color spectrum\", you have red, orange, yellow, green, blue, indigo, and violet. Those colors all exist as wavelengths. Purple does not. In modern parlance, purple is interchangeable with violet, but literally speaking it is the imaginary color between violet and red. Violet can be represented by the wavelength 400 nanometers, and red by as high as 780 nanometers (at which point it begins to get dull and dark as it slips into infrared), but purple cannot be represented by a single wavelength.\n\nSo, you might start by imagining the spectrum as a line\n\nRedOrangeYellowGreenCyanBlueViolet\n\nBut since it misses a color we use, you have to fold that line into a circle, or wheel, and tape it together with a new color, and you then get our color wheel.",
"Nobody has actually made this exact point, but \"color\" is made up in your brain. In reality it's just electromagnetic waves bouncing around. Your visual system applies color based on the receptors in your eyes. ",
"Imagine if you were blind and used three white canes (the sticks blind people use to walk) to navigate a bumpy road. You have one on the left, one in the middle and one in the right. They are arranged in a continuous spectrum from left to right.\n\nIf you felt a bump only with your middle cane, you would assume there is a bump directly in front of you. If you felt a slight bump with your left and middle canes, you would assume there is a single bump somewhere between the left and middle canes. And depending on how high one is over the other, you could pretty accurately tell how far left the bump is. A broad speed bump would lift all three canes. You have made a mental chart of all possible combinations and what road shapes they represent.\n\nHowever, in that chart is a weird combination: Your left cane and your right cane *but not your middle cane*. Even though a singular bump in the road can't do this, you have to put this on your chart as a valid combination because it does come up. If not for this strange combination, you could just have a straight, linear chart. But because of this odd combo you have to wrap your chart around a wheel.\n\nThose three canes are the red, green and blue color receptors of the eyes, and magenta/pink is the weird combination of blue and red *but not green*. And because we can see red and blue combined, the linear chart wraps around to include magenta.",
"To best answer you, color is a pretty nifty science if you look into it more. You might just think a red tomato is just red and that's it, but there's a lot more to that red than you think.\n\nFirst, color can be expressed as a wheel or in many other ways. Think of numbers. You can lay them out in a line to show magnitude, or you can stack them like block show volume, etc. There's many ways to visualize it. The color wheel as we're familiar with is typically the RGB one where it shows hue, saturation, value all in one 2D wheel.\n\nThis doesn't actually represent how the human eye sees things, so when while you're used to using it in a color picker on your computer screen, what our eyes typically see is better represented with the [CIELAB color space](_URL_0_). As you can see here, this is a 3D representation with hue on the X-Y axis and lightness on the Z-axis.\n\nIf you look beyond RGB and CIE, there's other color spaces like CMYK where you may be familiar with if you're in printing or textiles.",
"We essentially have 3 cones, each which is really good at sensing one particular wavelength, and starts to fall off in effectiveness as you go further away from it’s optimal wavelength. But, they all overlap regions. I think it is either the blue or the red that actually end up going up in effectiveness again near the opposite end, so that border colour will flare up both red and blue receptors. After this your brain has 3 values and you perceive different colour depending on how activated each of them are. So by the time it gets to your brain, it doesn’t really know the wavelength, or it doesn’t know that red < green < blue, it just knows 3 values and that they can each have varying levels of activation.",
"Just remember that all of our colour perception is generated by just three types of sensors/detectors (i.e., cones). \n\nThese three detectors or most sensitive to light at different wave lengths (Short/Blue, Medium/Green, Long/Red), so if you have a pure light source (i.e., just one wavelength) these three detectors will all respond to a different degree depending on the wavelength of that source. \n\nSo our sense of some lights \"colour\" is just the relative responses of these sensors (it's \"brightness\" is tied to the overall magnitude of responses)\n\nWhen one sensor responds much more strongly than the other two you see a primary colour (again depending on the wavelength either Blue, Green or Red). If they all have a strong & relatively even response, you perceive something bright and white(ish). \n\nThe thing that lets the spectrum get wrapped into a wheel is that most light sources are actually really complex and have power spread out over a lot of frequencies/wavelengths. \n\nWhat happens when two of the three sensors respond strongly? \nWhen it's the short and medium you get teal.\nWhen it's medium and long you get yellows and oranges.\nAnd when you have some light that stimulates both the short and long receptors without stimulating the medium receptor much you wrap around from one end (blue) to the other (red) and get shades of purple and pink and stuff that cannot be produced by a pure wavelength. \n\nSo imagine each group of cones produces a number corresponding to it's relative level of stimulation. For every set of 3 values there's a slightly different colour you perceive and as a result these perceived colours don't actually resolve themselves into a line but some kind of 3 dimensional colour space. \nThis has been characterized a number of different ways with [RGB](_URL_0_) being the closest to the way combining light works but others transformed to be more intuitive to humans (e.g. [Hue, Saturation, Light](_URL_1_) )"
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4ttx6w | why do flies have such short life-spans? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4ttx6w/eli5_why_do_flies_have_such_short_lifespans/ | {
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"Their lifespans are only short relative to human lifespans. There's no objective way to measure \"long\" or \"short\" when you're looking at organisms' life spans; these words only mean anything in reference to something else. You could just as easily ask why humans have such long lifespans.\n\nThere isn't a universal evolutionary pressure for organisms to have similar lifespans, so lifespan lengths are very diverse depending on the evolutionary strategy of the organism. One advantage of a shorter lifespan is the organism can evolve more rapidly and therefore adapt more rapidly to a changing environment. Conversely, the longer lifespan of humans allows us to develop into very complex organisms capable of high levels of intelligence and knowledge retention."
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4g4ihf | when people are in an accident and initially live, but then "succumb to their injuries" in the hospital, what do they actually die of? | Can't they just replace blood now? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4g4ihf/eli5_when_people_are_in_an_accident_and_initially/ | {
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"There are a variety of things. For example if the kidneys or liver are damaged and can't be repaired, then the body can't do the processing it needs and the body slowly poisons itself. An initially survived head trauma could lead to swelling that proves fatal. If the bleeding is internal, pumping more blood into the system might not help if it keeps leaking into the internal spaces. The surgery to fixed damaged organs can go poorly or allow an infection in. Those are a few examples.",
"They can replace blood, but blood loss is not the only injury...\n\nSome injuries take time to happen - if someone suffers an internal injury to some of their organs, it can take time for it to manifest - if your brain stops working you die instantly, if your heart or lungs stop working you die in a few minutes, other organs can take much longer.\n\nInternal injuries are also not so obvious and treatable quickly - a major laceration may take a few hours to actually kill you, but it is pretty obvious to a paramedic and can be treated. An internal bleed may take the same time to kill, bit won't be as obvious and can't be treated as simply, so will mean only getting treatment in the hospital, which can sometimes be too late."
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4ifl91 | why do we screw up our face when lifting heavy weight? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4ifl91/eli5_why_do_we_screw_up_our_face_when_lifting/ | {
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"text": [
"Its been scientifically proven that grunting reduces the level of perceived pain. I would assume that scrunching up your face achieves a similar effect."
]
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apzk1o | can us political candidates make campaign promises in the form of legally binding contracts? if not, why not? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/apzk1o/eli5_can_us_political_candidates_make_campaign/ | {
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"No.\n\nIn order for a contract to be valid there must be \"consideration\" on both sides. You cannot be contractually bound to do something for free, there needs to be some sort of exchange of value (and additionally it needs to be \"conscionable\" so absurdly one-sided contracts can also be thrown out). Furthermore valid contracts cannot demand one party break the law, you can't enforce a contract to commit a crime.\n\nThe intersection of all those factors is that a candidate trying to make a promise in exchange for a vote would be breaking the law (as it isn't legal to purchase votes) and if they were to just make the promise without the voters promising anything in exchange the contract wouldn't be valid either."
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31at6u | how come i can't tell you the order of the letters on a keyboard, but i'm easily able to type without looking? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/31at6u/eli5_how_come_i_cant_tell_you_the_order_of_the/ | {
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"text": [
"Because of muscle memory, your fingers know exactly where the keys are, even if you don't remember the order of them."
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sigit | like, really, explain like im 5. propulsion in space. how do space ships turn and about mass. | In 0 gravity space, does it take the same amount of force from an engine to propel something that weighs 30 tons and something that is 10 tons?
How does a ship turn in space? Do they need thrusters all around the ship? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/sigit/eli5_like_really_explain_like_im_5_propulsion_in/ | {
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"Well, you know that bully on the playground? How he always pushes you around? And you know how when he pushes you, he is pushed back a little too? The bully can't even stop himself from being pushed back when he pushes you, because every time something pushes on something else, that something else pushes back just as hard because of something fancy called Newton's Third Law of Motion. Well rockets in space work the same way. The rocket burns stuff and this makes reeeeeally hot air. Now, this hot air is moving really fast because when things are hotter they like to move. The shape of the rocket makes it so that the hot air that wants to move can only go out of the rocket in one direction. So it pushes the air out that way. Now what did we say earlier about things pushing other things? That's right, the other thing pushes back just as hard. So when the really hot air is pushed out the hole at one end of the rocket, it pushes back on the rocket and moves it in the other direction.\n\nEdit- read the rest of your question.\n\nA 30 ton object in space would require 3 times as much push to move the same speed as a 10 ton object.\n\nTo turn in space, yes, a spaceship can use its thrusters, or it can use gravity of large objects in space. You know how you jump, but you come back down to earth? Well this is gravity. What it is is that objects like to be closer to each other and pull on each other to get there. Larger objects pull harder. So in space, if the rocket wants to turn, it can go to where a planet or star starts to pull on it in the direction it wants to go, and just keep going straight but the gravity of the planet or star pulls it in the way it wants to go, if the space ship does it right.",
"FYI, there is no such thing as '0 gravity space'. Astronauts, space stations and satellites aren't floating up there, they're just strategically falling *around* the earth."
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99khlv | does starvation actually work towards weight-loss? if yes, why? if no, why not? and why do people think it does? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/99khlv/eli5_does_starvation_actually_work_towards/ | {
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"Well the body burns approximately 1500-2000 calories every day just to survive. If you do not eat food the body will burn fat to meet its energy and you will lose weight. This is however very unhealthy and should be avoided. If you binge on food after starving yourself for a week... you are just stupid. In one week of starvation you can expect to lose around 1-2 kg weight and risk becoming very ill. A better option is to control your diet and eat around 1200 calories a day.",
"For most people it doesn’t work because you get so hungry you simply don’t do it and end up binging. When you have an eating disorder it’s very different. \n\nIt’s an extremely unhealthy and even dangerous way to lose weight, and is very un successful. To lose weight you simply need to eat less, there’s not trick or special way to do it especially not starvation. We all know what to do, eat less and healthier. Some diets have health benefits but starving yourself certainly does not. "
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7rusgd | why is grilled chicken healthy and fried chicken not? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/7rusgd/eli5_why_is_grilled_chicken_healthy_and_fried/ | {
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"Fried chicken is considered less healthy because it is covered in an oily fried salty crust -- basically a salty donut is being added to your chicken. (And this is on top of the fatty skin, which is often left on.)\n\nThe meat itself is not unhealthy.",
"Fried = use of a lot of oil that is retained in the finished product for most traditional ways of frying\n\nGrilled = use of minimal oil that pretty sears the outside and cooks the inside through conduction\n\nYou need very little oil in your diet to be healthy when compared to other food portions, so all the oil that comes along with fried chicken makes it unhealthy",
"Here's a neat fact: If you remove the outer layer (skin/breading) fried chicken is almost always healthier than rotisserie chicken, because animal fat (which is what the rotisserie cooks in) is more caloric than the vegetable oil mostly used for frying chicken. \n\nAs others have said, what kills the healthfulness of fried chicken is it's outer layer. Breading is effectively the most caloric thing that people eat on a regular basis (usually being a mix of high calorie bread cooked in even higher calorie oil, to which it acts as a sort of sponge). When you eat, say, a chicken finger, it's not the same as eating a fried, egg, it's the same as eating a fried egg sandwich, where the bread of the fried egg sandwich was also fried. \n\nAnd, even if you go unbreaded, grilled chicken rarely includes it's skin, while fried chicken often does. Though not nearly as bad as breading, skin has a lot of calories/salt, and also absorbs oil."
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2v0zot | how would the coldest (27c) star / brown dwarf feel to a touch (wise 1828+2650)? | Lets say - if we were not immediately sucked in and destroyed by its gravity, how would coldest (27C avg) brown dwarf star "WISE 1828+2650" feel like to a touch with a bare hand?
Is it even never possible to guesstimate? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2v0zot/eli5_how_would_the_coldest_27c_star_brown_dwarf/ | {
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"Are you asking how warm 27C is? Or what it's like to put your hand into an alien atmosphere? ",
"You'd get radiation burns and probably radiation poisoning. Conventional stars can't be alive and *not* emit radiation (usually). What would that feel like? You'd feel tingling of the limbs, swelling of the tongue, and a \"burning up\" sensation (to quote from a very unfortunate worker at some plant that was mixing too much plutonium into mixture which caused a criticality, or a very violent tiny nuclear fission reaction, but I can't remember where this happened).\n\nNeutron radiation is a nasty thing.",
"It'd feel like your hand is being ripped off by gravity at a nice temperature."
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2wxgpv | why is it that passengers fall asleep when the cabin pressurizes? | I'm flying to Miami right now and I've always wondered this. As soon as the cabin pressurized, people around me fell forward and instantly asleep, others on take off.
I can't do this and I never understood why this is. Why does it work only on some people? It's kind of freaky. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2wxgpv/eli5_why_is_it_that_passengers_fall_asleep_when/ | {
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"I tend sleep on flights. It's not because of the pressurization -- it's because I'm strapped to an uncomfortable chair for a few hours, and sleeping is like a time machine to final approach.",
"The cabin is not suddenly pressurized. It is gradually pressurized as the airplane climbs, with an increasing pressure *differential* as the outside pressure drops, starting from the atmospheric pressure of the departed airport.\n\nHowever, what *actually* happens, from your metabolic viewpoint, is that the pressure in the cabin drops as the airplane climbs. If there is an effect, it's simply from the drop in blood oxygen that results from the drop in cabin pressure.",
"It rarely has anything to do with pressurization. You're confined in a small space, with the white noise of engines, little to do, and are likely tired from traveling. Putting those together makes it highly conducive to sleeping."
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31ax66 | how did switzerland (specifically geneva) become the capital of international relations? | Sure, the neutrality is a reason, but there are other neutral nations. Besides, Switzerland is among the most expensive countries. What historically made it the capital and what keeps it being so to this day? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/31ax66/eli5_how_did_switzerland_specifically_geneva/ | {
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"text": [
"It has a long history of remaining neutral in the various wars of Europe and neutral places are preferred for making treaties. That really is it. "
]
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130u86 | the difference between java and javascript. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/130u86/eli5_the_difference_between_java_and_javascript/ | {
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"It's easier to explain how they're the same.\n\nThey both use the word *Java* in their names.\n\nThat's all.\n\nIt's like how Clint Eastwood and I are the same. We both use the word *Clint* in our names. Otherwise, we're completely different people, and we're not interchangable in any normal sense of the word.\n\nSame for Java and Javascript. (I think JavaScript's official name has been changed to ECMAscript.)",
"JavaScript was originally named LiveScript, but some businesstypes wanted to somehow use the high (at the time) popularity of Java to encourage people to use it, so they changed the name.",
"Both can run in your web browser to make cool stuff happen.\n\nJavaScript is a scripting language that a browser can run on its own, without having to download any add-ons. JavaScript can manipulate the HTML (most of the images, text, etc you see on webpages) or otherwise work with the built-in parts of browser. Most of the cool interactive parts of the web today are made with JavaScript.\n\nJava is a much larger language that's used for many different things, but one implementation that was much more popular in the 90s was Java Applets. You would have to have your browser download a Java plug-in so that you could run self-contained programs.\n\nThe actual code is very different. They were not written by the same people. The similarity in naming is intentionally confusing: Java was popular when JavaScript was first being written, so they lifted the name to get it off the ground.",
"Java : JavaScript :: Car : Carpet\n\nWell, not quite, but a ruthlessly accurate answer would be less amusing. ;)",
"Javascript is a web scripting language. When you view a webpage in a browser, the web developer probably put some javascript in that page. The javascript, which is written in the webpage, is executed by the browser to do cool things on webpages.\n\nJava is completely different. Only the name is the same. Java is not run by the web browser. It is run by software on your computer. A java program is basically a file which a program on your computer (called the java virtual machine) executes, and operates hat code to make a program that operates separately from your browser. However, sometimes you can embed java in a webpage, which is called a java applet. In that case, the jave program shows up in the web browser, but it is really being run by the java virtual machine, not the web browser.",
"[How my web programming teacher explained it](_URL_0_)",
"Java is a programming language built for a special virtual computer you run inside your computer. The benefit to this is that all a person has to do is make sure they have the ability to run the virtual computer (the JVM) and any program written in Java - in theory - will work perfectly.\n\nJavascript is a form of script that web browsers read when drawing a webpage that gives it features similar to (or that of) regular computer application. It is not related to or made by the same company Java was made by (Sun) or is currently made by (Oracle). It was just a programming language that was being made while Java was popular for embedding in websites and the creators figured naming it similar to Java would boost its popularity. It worked very well.",
"Java is for application developement, and javascript is for making websites."
]
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[],
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[],
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"http://www.youtube.com/watch?v=wgOgD_WbRXg&t=00m05s"
],
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||
4rws3l | do the signs on the backs of trucks that say, "warning stay back 200ft, not responsible for broken windshields" carry legal weight? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4rws3l/eli5do_the_signs_on_the_backs_of_trucks_that_say/ | {
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"It depends. If they have a tarp or cover on the load and your windshield gets broken by something coming out of the bed then yes, in a lot of cases they are covered because they took every reasonable precaution. If one of their tires kicks up a rock off the road that's a common road hazard and usually isn't covered either. If the load isn't covered in any way then the company can be, and in several court cases has, held liable for damage cause by an unsecured load. \n\nSource: 10 years trucking. ",
"They carry zero legal weight in cases where something falls from the truck. You can't unilaterally disclaim liability for negligence. Loads are required to be secured in every state. The driver would be negligent by either not securing the load or improperly doing so, and a single stone falling from a truck is an unsecured load. They generally would not be liable if they truck were to kick up and object from the road that did not originate from the truck.\n\nNow getting them to pay is a another matter. First off, you have to prove that the item came from their truck, then you have to deal with their internal claims departments in many cases which will often stonewall, even for provable cases."
]
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[],
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||
8quocm | unsupervised learning/machine learning and how data is relevant | [deleted] | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/8quocm/eli5_unsupervised_learningmachine_learning_and/ | {
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"Unsupervised learning isn't generally used to make predictions - for that task a supervised learner is typically used. You hinted at why in your question - if we *do* have a way to evaluate whether our predictions are accurate, then we should be able to frame the task as a classification problem and train a supervised learner to make predictions.\n\nUnsupervised learning is used when we don't have a way to separate old instances (students in your example) into labeled \"classes\" that we care about predicting for new instances. Depending on what model you use, an unsupervised learner might find groups of students who are similar in some way, or it might find which feature values are linked together in some predictable way, or it might point out students that are abnormal (in some way) with respect to the general population.\n\nSometimes you can go in after-the-fact and see that your unsupervised learner has separated students into groups that you can make sense of, or that you can tell why anomalous students are anomalous. But that's not guaranteed.\n\n & nbsp;\n\nIf you have *some* labeled data but not much (say you have data about some past students who have performed well), you could run an unsupervised learner (say a clustering algorithm) on all the students and see if those labeled students fall in a single cluster, but there's no guarantee. A more popular approach here is probably *semi-supervised* learning, which uses unsupervised techniques along with some labeled data to build a predictive model."
]
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[]
] |
|
czr17j | what is the significance of bauhaus? | [deleted] | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/czr17j/eli5what_is_the_significance_of_bauhaus/ | {
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"text": [
"the band or the artist collective?",
"Bauhaus is a run of the mill asteroid. It is about 9.6km in average radius. It is part of a family of asteroids that may remnants of a collision of some celestial body with the asteroid 221 Eos approximately 1-2 billion years ago.\n\nIt is of no particular significance.",
"Bauhaus was a school of design in Germany that was shut down by the Nazis. \n\nBut the word has since grown to mean a style of minimalism and simplicity, used in art, architecture, furniture, typography, etc. It’s also grown to mean a movement that ushered in the current style we now call “modern” (think 1950s sleek styling). \n\nBauhaus was a rebellion against the classical ornate style that was popular in Europe 100 years ago. It preferred fonts without serif (ie, sans-serif), buildings without decoration, embraced modern art in graphic design, etc. These ideas have become so popular in western culture since then, that they are now de facto mainstream.\n\nThe bauhaus movement is the grandfather of modern design, and our world would look a lot different without it."
]
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[],
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1y6e5c | why do we need suffixes in web addresses? e.g. .com, .org, .gov. | Why can't I just connect to a website by typing in "youtube"? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1y6e5c/eli5_why_do_we_need_suffixes_in_web_addresses_eg/ | {
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"Think of the top level domains (like .com, .org, .edu) as area codes on a phone call. Every new TLD or area code adds a whole lot more possible addresses. ",
"It's just a naming convention. The idea in the beginning was that different types of websites should have a different ending. So commercial websites should end with .com, while organizations use .org. Schools use .edu and so on.\n\nSome of these however got mixed up with time and the rules are pretty lose (with the exception of some special ones like .gov goes for governments - you can't just buy one of these).\n\nDifferent countries also get a different suffix (it's called domain). This is useful because the same name can be used several times. For example, an Italian company called \"Something\" might have the same name as a Bulgarian company. The Bulgarian company can use \"_URL_1_\", while the Italian one can use \"_URL_0_\".\n\nAnd the person that opens \"_URL_1_\" knows it is about the Bulgarian company (not the Italian one), because of the suffix. The same goes for the other suffixes. If you open .gov website, you know it is an official government page, not something a few jokers made up.",
"The way it works is that when you type _URL_0_, it will ask the person who owns .com what the IP of X is.\n\nWhat you are asking is, why not always ask the same person and keep all of those directory at the same place.\n\nThe problem is mostly political. Having only one person/gov/society who owns every single domain name on the planet would be a bit problematic.",
"Web addresses are broken up into two main parts, the domain and the directory. It is formatted such that _URL_1_.the.domain/this/is/the/directory. Technically, there is another dot at the end of the domain, but it's typically omitted and simply implied (i.e. domain./directory). Domains are read from right-to-left (i.e. domain- > the- > is- > this), and in order to locate a server or website or what-have-you by its domain, you have servers responsible for maintaining a list of everything to the left of itself. So, the server responsible for \"com\" needs to know how to find _URL_4_ and _URL_0_, then x and y are each responsible for something.x or somethingelse.y, etc. The reason for the limited number of top-level domains is basically that the root name servers (the ones responsible for that last dot), are the front-facing lookup directory for *the entire internet* so it makes a huge difference that they only have to maintain records for a small number of targets. Granted, that just passes the buck a bit, since the TLD's like com and net have pretty massive number of lookups to manage, but still, it takes that load off of the root name servers to some extent. At this point, it's far less of an issue than it used to be, and there has even been talk of allowing custom TLD's to be purchased (currently you can't buy a new TLD, you can only buy a domain under a TLD unless you get into alt nameservers, but that's a whole different ballgame).\n\n\nNow, what that means is that if you happen to own _URL_4_, you also own _URL_3_, BUT, you're responsible for maintaining and serving the lookups for any subdomains you create. You also own _URL_2_, because those typically map to the natural folder structure of the files that comprise your website.",
"Imagine there's a YouTube University, as good as Stanford and Harvard.\n\nWhich youtube do you want? The university or the video-sharing site?\n\nAnd what if there's a youtube amusement park in Australia?\n\nDomains are divided up by country, type, and then finally the actual domain name.\n\nIn the above example, it would be: Australia, a company, youtube.\n\nBecause dns drills down from generic to specific, it reads \"backwards\" to humans, as in: _URL_0_\n\nAmerican domains don't need a .us at the end, it's implied, because we invented the internet and because 'Murrica.\n\n",
"When the Internet first came about and there was a need to identify networked machines using a more memorable syntax than IP addresses, it was still decades away from being commercialized. There was a value in having different registries for educational (.edu), governmental (.gov), military (.mil) entities, non-profit (.org) and commercial (.com) entities who could come up with their own methods and requirements for registering machines on the Internet. \n\nWhen the web took off, companies started to flood the web and a gold rush ensued on .com addresses. As a lot of the good names got taken up, some looked to alternate registries such as .net and .org who didn't really restrict their use to the intended purpose. Because .com was so common, and alternate top level domains were seen as confusing to consumers, companies started to buy up domain names on multiple TLDs to avoid problems like the _URL_0_ fiasco. \n\nNowadays, because so many companies/individuals have registered many more domains than originally envisioned and domain speculators are squatting on so many useful domains, domain registrars are trying to open up new TLDs that can sensibly divide up the name space, usually with industry specific purposes that aren't quite so ambiguous (.law, .construction, .hotel, .music) as well as usage specific ones (.mail, .blog, .shop, .app) although there are some more generic ones as well (.site, .web, .online, .home).\n\nSo ultimately we're in a long transition from a system originally designed to identify machines on a (inter)national network composed of a wide variety of organizations, to a system driven primarily by commercial entities to identify websites and applications on the Internet. "
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"something.bg"
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"this.is",
"x.com/everythingelse",
"everythingelse.x.com",
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"youtube.co.au"
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2g1o4r | if the carbon in the air is absorbed to the ground isn't that bad for the soil? | The reason why i ask is because of this article in which they say the plant could absorb the carbon in the air and transfer it to the soil,but to me that seems like a accident waiting to happen.
_URL_0_ | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2g1o4r/eli5if_the_carbon_in_the_air_is_absorbed_to_the/ | {
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"ckes5yd"
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"score": [
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"text": [
"All plants absorb carbon dioxide and use it to transform into cellulose to build the plant. Trees, grasses, flowers, bushes. Those are all fires awaiting a spark."
]
} | [] | [
"http://thinkprogress.org/climate/2014/09/09/3478143/black-fingers-of-death-climate-change/"
] | [
[]
] |
|
1x9uet | why are most new dvd menus still 4:3 instead of 16:9 | I have a slightly older HDTV (only has one HDMI plug). Every time I put in a DVD, I have to click the change ratio button to 4:3 just to see the options at the bottom of the screen (first world problem, I know). It has been getting annoying that I then have to switch it back to 16:9 to watch the show or movie. This happens even with new releases that just came out. Is there a specific reason the DVD publishers are still using 4:3 menus? I do not have a BluRay player, so I cannot confirm if this is also a problem with BluRay discs. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1x9uet/eli5_why_are_most_new_dvd_menus_still_43_instead/ | {
"a_id": [
"cf9fnx6"
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"score": [
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"It is not a problem with the DVD, it is a problem with your set-up. \n\nMy guess it that your misconfigured DVD player outputs a \"squished\" 4:3 signal that you \"correct\" by pressing \"zoom\" or \"stretch\" on the TV remote. It fills the screen for 16:9 material, but that setting doesn't work on 4:3 menus. (You are effectively zooming and trimming for the 16:9 picture so you don;t see the error there.)\n\nYour DVD player should be configured to be outputting a 720/1080 signal, and you should not be using the panel/zoom/stretch feature on your TV. Those picture settings are band-aids to correct poor source material (\"lets zoom this widescreen laserdisc\") or ignorant choices (\"Let's stretch this home video to fit our wide tv, who cares if it makes everybody appear fat and more grainy\").\n"
]
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[]
] |
|
4cp2xx | why does caffeine have a half-time? why isn't the metabolizing speed constant? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4cp2xx/eli5_why_does_caffeine_have_a_halftime_why_isnt/ | {
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"d1k7199",
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"text": [
"When there's half as much caffeine in your body, there are half as many chances for each caffeine molecule to bump into the caffeine-destroying mechanisms that your body has. Those interactions happen pretty much at random.",
"Most things your body processes have a half-life.\n\nIn a way, this is because the processing speed *is* constant. You might think that your body should process perhaps 10g of something in an hour until it's all gone, but as the concentration drops it's harder to find, so it takes longer.\n\nInstead of an office worker sitting with a pile of papers to deal with, it's more like a blackberry picker who has to search for fruit. The fewer there are left, the longer it takes to find."
]
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[],
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||
5j825y | why do senses like sight and hearing tend to deteriorate with age? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5j825y/eli5_why_do_senses_like_sight_and_hearing_tend_to/ | {
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"Sight deteriorates largely because the focus point for an image moves off of the fovea, normally the focus ends up behind the fovea, making the person farsighted. When it is associated with old age, this is called [presbyopia](_URL_1_). The lens is what focuses light into the eye. As we get older the lens gets less elastic, which is why older people also take longer to switch focus from something close to something far. The loss of elasticity of the lens is what causes the sight deficits due to age.\n\nAs for hearing, the deterioration depends on how you treated your ears throughout life. Prolonged exposure to loud sounds will cause the deterioration to happen faster. The damage comes from various changes in the cochlea as you get older (or in response to damaging sounds). Part of the cochlea, the basilar membrane, is what vibrates through the cochlea in response to sound. This vibration of the basilar membrane transmits the sound to the organ of corti, which transduces the sound into neural signals. As you get older (or damage your ear) the basilar membrane will become stiffer, which causes the loss of higher frequency sounds. The cells in the organ of corti can also degenerate, furthering the loss of hearing. The loss of hearing due to age is [presbycusis](_URL_0_)."
]
} | [] | [] | [
[
"https://en.wikipedia.org/wiki/Presbycusis",
"https://en.wikipedia.org/wiki/Presbyopia"
]
] |
||
61xa7a | why do people answer questions better if they look at a different direction rather than maintaining eye contact with the person? | [deleted] | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/61xa7a/eli5_why_do_people_answer_questions_better_if/ | {
"a_id": [
"dfi1hx7"
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"text": [
"Because eye contact is emotionally draining. We use up a lot of mental processing power looking at another person - discerning their expression, hypothesizing their intention, their thoughts, their motivations. \n\nIf we are trying to do something else - like find the solution to an abstract problem - it is much easier to do this without exhausting mental resources on engaging with another person."
]
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[]
] |
|
17ob63 | why do constellations look nothing like what they are supposed to represent? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/17ob63/eli5_why_do_constellations_look_nothing_like_what/ | {
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"text": [
"It takes imagination and creativity.",
"They are just dots in the sky, it's not like early astronomers and navigators who named these constellations could just rearrange them to fit the shape perfectly of whatever it was. In fact, many constellations with the same star structure are called different things by different cultures -- who made up the constellations independently of one another."
]
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[],
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||
1vfc4z | what's happening when i put my car in park, take my foot off the brake, and feel like its rolling back a tiny bit? | I think this happens with all cars. You pull into your parking spot, your foot is on the brake, you put it in park, take your foot off the brake, and then you feel it seem to roll back. What's happening to cause that movement? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1vfc4z/eli5_whats_happening_when_i_put_my_car_in_park/ | {
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"Putting your car in park is basically sliding a lock into place in the transmission, which is just a collection of gears that control how the power from the engine is transferred to moving the car. Since there is a little bit of play in those gears, they move a little before the lock catches and the car rolls a little. It will roll more if your transmission is worn out.",
"When you engage \"park\" you're actually sliding a pin into a notched collar around the driveshaft. This pin, called the pawl, locks the driveshaft into place, preventing the driveshaft from moving. However , there's a little play built into the system. Were it a perfectly tight fit, it would be too difficult to slide the pin in sometimes. The roll back or forwards is just the driveshaft taking up the slack. From Wikipedia's parking pawl page: \n\nMost vehicle manufacturers and auto mechanics do not recommend using the transmission's parking pawl as the sole means of securing a parked vehicle, instead recommending it should only be engaged after first applying the vehicle's parking brake. Constant use of only the parking pawl, especially when parking on a steep incline, means that driveline components, and transmission internals, are kept constantly under stress, and can cause wear and eventual failure of the parking pawl or transmission linkage. The pawl might also fail or break if the vehicle is pushed with sufficient force, if the parking brake is not firmly engaged. Replacement can be an expensive operation since it generally requires removing the transmission from the car"
]
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[],
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368xeq | why can i run for half an hour on a treadmill without being tired, but running on concrete for a couple of minutes tires me and makes my legs hurt? | Pretty much the title. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/368xeq/eli5why_can_i_run_for_half_an_hour_on_a_treadmill/ | {
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"text": [
"A few reasons, mainly:\n-More impact on your feet, and stress on different parts of your legs when you run on treadmill vs. road, you land differently on your feet due to self controlled running vs. sort of running in place. Be more aware of your feet, you can look up more about proper running form.\n-No incline on treadmill\n-You aren't managing your pace well, use a GPS running app or pedometer and timer to track your pace, and try to keep it consistent with close to what you usually do on the treadmill",
"Treadmills have a shock-absorbing design, while concrete is hard. You might have a better time running on grass or on a dirt trail.",
"The treadmill is already moving for you; you just need to lift your feet up so you don't fall backwards and look stupid in front of the whole gym.\n\nThe concrete, or grass, or whatever solid ground you're on, isn't going to move for you. You have to use you leg muscles to push yourself forward.\n\nEdit: I ran treadmill for 6 years, then moved and ran outside ever since. I've pretty much noticed the same thing you did. ",
"Your trainers/sneakers that you're using could also be an important factor. As someone already said, treadmills have a shock-absorbing design so it mitigates the effect of unsuitable trainers. On concrete there's no hiding place for your shoes which may be why you notice. If you want to continue running on concrete you might want to consider going to a specialist running shop to get a professional fitting. Shoes vary widely according to design. My old pair were ASICS and running 30 minutes hurt like hell - I ended up with shin splits (where the shins just above your foot ache like hell). I swapped them for a new pair of ASICS after seeking advice - it turns out I have flat feet + the way my foot lands was also unsuitable for the shoes I used. My shoes are no longer the limiting factor, now it's my fitness - I can easily run 10km in the new pair with no ill effects (at least not to my shins).\n\nFor more on the topic, refer to /r/running"
]
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[],
[],
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|
dk71lr | why are phone screens so hard to see when you film them? | We can see them very well, but cameras seem to have a hard time capturing them. Why? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/dk71lr/eli5_why_are_phone_screens_so_hard_to_see_when/ | {
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"my best guess is because its just emitting light. have you ever tried recording the sun? it basically just blocks out anything being recorded. why the camera cant record light is probably really simple but i dont really know the reasoning behind it either.",
"The screens have a refresh rate, where the entire screen is converted from one image to another like a flip book. The faster the pages flip, the better it looks to us. \nCameras record in a similar way, taking pictures at a quick pace. Which when shown rapidly makes a movie, like pre-digital theater projectors.\nThese picture flips/frame rates are usually different or started at different times so that the camera takes it's snapshots between screen refreshes causing a flickering.\nI believe there is more to this if someone else wants to add on or correct me."
]
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[],
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|
1y6sl6 | how do objects get named? (for example 'blanket' and how do the powers that be decide what is called what.) | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1y6sl6/eli5_how_do_objects_get_named_for_example_blanket/ | {
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"Adding to this question, I've always wondered how a gender is chosen (in languages that do that) when a new object is invented or discovered. Who decides if it's a Le or La or an El or a La?",
"The human brain named itself",
"Words can come from many sources, but most standard English vocabulary comes from one of two places: Latin (via French) and Germanic (via a lot of Northern European languages). This dual origin is one of the reasons for why English has so many synonyms. For example, [*old*](_URL_0_/index.php?term=old) comes from the West Germanic *althas*, but [*ancient*](_URL_0_/index.php?term=ancient) comes from Old French *ancien*, which itself comes from Latin([ish](_URL_1_)) *anteanus*.\n\nIn your specific example, [*blanket*](_URL_0_/index.php?term=blanket) comes from the Old French word *blanchet*. Contrast it with [*sheet*](_URL_0_/index.php?term=sheet), from proto-Germanic *skautjon*, another example of English getting two similar words from different sources.\n\nSo there are no \"powers that be,\" only people who use words, and as people change and words change, languages develop and change. Etymology is the study of these changing words. To find the details of a specific word origin, you can use a special dictionary, such as the [OED](_URL_2_) or the free [EtymOnline](_URL_0_).\n\nTL;DR: Words come from older words. Look [here](_URL_0_) to find out which words come from where.",
"Try the [Online Etymology Dictionary](_URL_0_)\n\nBlanket\n > c.1300, \"bed-clothing; white woolen stuff,\" from Old French blanchet \"light wool or flannel cloth; an article made of this material,\" diminutive of blanc \"white\" (see blank (adj.), which had a secondary sense of \"a white cloth.\" Wet blanket (1830) is from the notion of a person who throws a damper on social situations like a wet blanket smothers a fire. In U.S. history, a blanket Indian (1859) was one using the traditional garment instead of wearing Western dress. ",
"My favourite is \"fireplace\". Such a cave man thing. \n\n\"This place for fire. Fire place!\"",
"when the Normans, who spoke a romantic language similar to french, gained control of England, they became the lords and ladies of the island. meanwhile the \"natives\" (quotes because, like the US is today, England was mostly made up of immigrants. Vikings, Danes, Angles, Saxons etc), who spoke a language based on Germanic tongues, were forced to become the laborers and servants. this lead to a lot of different synonyms in English based on who was speaking. the Normans spoke about the meat that they ate as pork, beef, poultry etc, meanwhile the English spoke of the animals they raised as pig, cow, chicken, etc. these word differences come from the different languages being used. \neven today, the different connotations (every day meanings) of words correspond to the base language it comes from. for example, \"a cordial reception\" means the same thing as \"a hearty welcome\" but they are used in completely different circumstances. \"cordial reception\" comes from Norman french, and \"hearty welcome\" comes from Germanic Anglo tongues. \neven going farther back into English history, we can see place names display the different language bases. when the vikings took over England, they took the nice fertile valleys, forcing the Saxon folk who were living ion the island into the hills. now, rivers and towns in the valleys still sometimes carry viking based names, while towns and rivers in the hills tend to carry Saxon based names. basically English is a creole tongue created out of all the languages brought to the British isles.",
"Objects are named by the people who find or invent them. \n\nIf you are talking about typical objects today, you can retrace most of that to Germanic languages and Latin. All of which came to be from ancient times where people made \"sounds\" instead of \"words\" that eventually resulted in a mutual understanding of the sound and thus an object was identified by a certain sound. We now call that a \"word\".\n\n"
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ba8zve | for the average person in developed countries like the usa, how much has life changed (in economic terms) today compared to 50 years ago? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/ba8zve/eli5_for_the_average_person_in_developed/ | {
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"Drastically. The cost of living has risen disproportionately compared to salary & wage increases for the average worker, particularly the working class (blue collar or service industry jobs). Execs in the upper echelons of the corporate industry have received those raises, though, and it's creating a larger gap between the haves and the have-nots (bourgeois and proliteriate). \n\nFifty years ago, you could work your way through college at a minimum wage job. You could buy a house right after college. Not anymore. My 21-yr-old goes to university full-time and works part-time. She makes enough money to make her car payment, pay insurance, and a get few groceries. She still lives at home and I don't see her being financially independent enough to even move into an apartment with roommates for several years. It's really sad. "
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201xek | why is 'butt chugging' a trend? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/201xek/eli5_why_is_butt_chugging_a_trend/ | {
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"Some dumbass Pi Kappa Alpha at University of Tennessee decided that it would be a brilliant idea to pour alcohol up his ass to get really drunk. Ended up getting hospitalized and once news spread of this idiots actions the story ended up getting picked up by a lot of media outlets. Pi Kappa Alpha ended up getting suspended from the university for the instance to cap everything off.\n\nFrom that point it just became kind of a funny thing on college campuses. It's not like an actual trend people do, more joke about. "
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18qfam | why are food cans ribbed? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/18qfam/eli5_why_are_food_cans_ribbed/ | {
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"Structural rigidity. Same reason corrugated cardboard is stronger than paperboard.\n\nedit: a ribbed structure can be compressed because the ribs can bend and flex, whereas something like a soda can has a harder time being compressed because the metal might just shatter instead of bending. ",
"Came here to say \"for her pleasure\" someone already gave a legit reason though ",
"I was always told that the ribs were for support and structural integrity. They also allow whatever's in the can to come out easier due to the fact that they trap air around the sides allowing the material so slide out easier, or so I've been told."
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7lgpdj | what is a government bond? | I can't seem to get it for some reason. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/7lgpdj/eli5_what_is_a_government_bond/ | {
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"It is a loan that the Federal or State government gives to a local government for a specific project. Repairing roads, building schools, establishing a city park, etc. The local government gets the money now to do the project then pays it down over time rather than having to wait that amount of time to save for the project (which will make whatever issue they are trying to correct worse). \n\nEdit: You can also have the Federal Government give a bond to a State Government. \n\nEdit2: Treasury bonds, which you might be thinking are Government bonds, are a point of investment. You buy them at a set rate of interest for a set period of time. During that time the money you gave the government is used to fund their various activities and then they pay you back with the interest when the bond matures. ",
"You give the Canadian government some money upfront, say $1000. The government will return this face value to you upon maturity (say 10 years). Until then, the government will also give you semi annual payments called coupon payments. \n\nSo total cash flow to you looks like:\n\nYou net zero on the $1000 (you give it to the government initially, and then they give you it back upon maturity) \n\nAll the semi annual coupon payments you get from the government. Probably around $10-30 or something around there.\n\nGovernment bonds are considered risk free, because technically the government can print more money in order to pay you back.",
"You give the government $1000 today and they give you back $1000 plus interest at a later point.",
"It is how governments typically borrow money.\n\nYou are the mayor and you need to build a new $10 million dollar bridge. You don't have that kind of money, and don't want to cut city services for a few years to try to raise it...do that, and you might not be mayor anymore. So instead you sell bonds. People pay $100 for a bond, and in 10 years they get, say, $120 back for each one. The interest usually isn't very high, but governments rarely fail, so it is usually a very safe investment.\n\n"
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4qq1qu | why are governments compensating taxis for the rise of ride-sharing services like uber? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4qq1qu/eli5_why_are_governments_compensating_taxis_for/ | {
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"Because ride sharing programs are bypassing laws, safety regulations, and regulatory fees, basically cheating the system and bypassing the actual free market. ",
"No. We don't have free markets. \n\nThis is a huge pet peeve of mine. Because people like to act like we have free markets, blame them, and then call for more regulation. No, we don't have a free market. We have a regulated market. But instead of acknowledging that, they just call it a free market and try to push us further into a regulated market. ",
" > Isn't it a free market?\n\nWith taxis, no, it is not a free market.\n\nCities regulate taxis, because they don't want too many of them clogging the streets and polluting the air. They only give out so many licenses, and decides which companies get how many.\n\nWhat makes a taxi different than a car service is you don't schedule them. They drive around offering service on demand.\n\nUber exploits a loophole by using smartphone to provide a service that is almost exactly like a taxi, but is technically scheduled in advance. This allows Uber drivers to avoid the strict regulation taxis go through. Many taxi companies feel it is unfare they have to follow the rules but Uber does not.\n\nAlso, \"compensation\" doesn't mean \"give them money\". It likely means reducing fees and regulations to help taxis compete.",
"In my country, taxi cabs are an essential service for the elderly, disabled, sick, etc. Uber doesn't service this market.\n\nIf there were no taxis, there would be a bigger demand on public services and thus huge expense to the government to make up the shortfall. \n"
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67c3ax | why new ships are pushed sideways into the water ,isn't it dangerous | here is a reference video
_URL_0_ | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/67c3ax/eli5_why_new_ships_are_pushed_sideways_into_the/ | {
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"They are launched that way when there isn't enough room to launch them lengthwise. Look at the video you posted, every one of those is on a narrow river or canal.\n\nIf you plan it right it's no more dangerous than any other kind of launching, but it requires more planning and a hull with a low center of gravity.",
"The launchers know how fast the ship will move, how heavy it is, the shape, and can work out that it won't capsize. It can be gentler on the ship than a straight launch; when a ship is launched straight it will for a brief moment have its bow supported by the water, its stern on the slipway, and the middle in the air which bends the ship. The sideways launch also means the ship is going to slow down quickly.\n\nAs one of those clips shows, it can certainly be dangerous to someone in the wrong place. And like everything, it is possible to get it badly wrong (and capsize the ship, probably)."
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8sj20n | why is water bottle cost so much when they're sold separately? | [deleted] | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/8sj20n/eli5_why_is_water_bottle_cost_so_much_when_theyre/ | {
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"Because it's profitable to sell it.\n\nRetail price is picked to be as high as possible to maximize profit. The production cost of the bottle water product is pennies per 1000 gallons"
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3dtfy7 | why does the value of my country's dollar (australian) fluctuate so much against the euro/usd/gbp? | When I was in the United States in 2012, the Australian Dollar was worth about $1.05USD which was great for me because it meant I could do tons of shopping and have a pretty cheap holiday given American prices tend to be lower than Australian Prices.
Fast Forward to today, the Australian dollar is only worth $0.72 USD and people are saying it will be $0.65 by the end of the year, which is majorly disappointing because I was hoping to travel at the end of the year and now it's more expensive and buying things is far more expensive for me because I have to pay the inflated Australian prices since my days of importing cheaply from online are over.
But as someone who just can't wrap her head around maths and how the economy works, I don't get it and why the value of money can change so much. So....can someone explain this one to me like I'm 5? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/3dtfy7/eli5_why_does_the_value_of_my_countrys_dollar/ | {
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"The aussie dollar did have a big run up vs the u.s. Dollar when the GFC hit because australian interests rates remained relatively high, and thus attractive to foreign investors - driving its price up. Think of it like anything you buy - if there is more demand for it the price rises.\n\nHistorically - the aussie dollar is more likely to be valued where you see it now - which is good for our exports (they become attractive for foreign markets then).\n\n",
"As the Australian economy is waning the government has taken actions to reduce the value of the Aussie dollar by lowering interest rates. By lowering the value of the dollar, imports become more expensive and exports cheaper, therefore making Australian goods more appealing to buyers and stimulating the economy.\n\nSadly for us this means the dollar is dirt compared to other currencies like the British Pound."
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67u0qg | why can't we just install windows on consoles (xbox scorpio etc.) if they're so powerful to run hardware intensive games? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/67u0qg/eli5_why_cant_we_just_install_windows_on_consoles/ | {
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"Windows is designed to run on standard PC hardware. This makes certain assumptions about the CPU, how it's connected to the rest of the system, what's provided by BIOS/UEFI, built-in interfaces for everything from keyboards to clocks and a whole bunch of other stuff. They're basically built to be backwards compatible to the original IBM PC from 1981.\n\nConsoles don't need to bother with that. They're built with a single purpose, playing games & they can get better performance at lower costs by not being PCs - *that's what makes them consoles*.\n\nAnother design goal is that consoles are *supposed* to be simpler than PCs. They're intentionally meant to be simpler, more stable & more secure at the expense of flexibility.\n\nOn top of that, the cost of console hardware is subsidized because console manufacturers expect to make a certain amount of money back by licensing deals on games sold for the system. If you allow some sort of open OS, like Windows, people can install whatever they want without the manufacturer ever seeing a dime. The cost of the hardware would have to go up if this subsidy went away.\n\nAt the end of the day, however, the XBox **does** run a trimmed down version of Windows at its core. You probably can't see or feel it as a user but, to the developers of games, they're very nearly the same as a desktop PC running Windows.",
"Because Microsoft don't want you running regular Windows on an Xbox One. They don't provide a way of installing it, and they have various security features to prevent people installing and running unauthorised programs.\n\nHowever the hardware is similar enough to a PC that if someone manages to break the encryption it is possible that Windows could be installed on it. It might not run that well though because there aren't freely available Windows drivers for the exact hardware an Xbox One has.\n\nThey aren't particularly powerful compared to a decent PC though, so I'm not sure what benefit it would have. Part of the reason they run games relatively well for the hardware they have is that they are running a stripped down OS which allows games greater access to the hardware than you get on a PC. So you'd lose that benefit if you were running regular Windows on it.",
"Windows is designed to run on a PC. But a console is not a PC. The latest consoles do use an x86_64 processor and similar hardware as you would expect in a PC but that is just parts and not everything that Windows expects to be there. When designing a new console with a new operating system you can omit a lot of the old standards and conventions of old computers. This does not mean that you can not port an OS to a console. Linux have been ported to PS3 and PS4. However that takes time which Microsoft is unwilling to do with their Windows."
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ehx7j9 | how does the hydrolysis of atp actually transfer energy to another molecule? | So I understand that the hydrolysis of ATP is exergonic reaction but how does that free energy transfer to another molecule/enzyme? Is the hydrolysis of ATP raising the local temperature and thereby giving energy to the molecules nearby or is there some transferring of high-energy electrons via the gamma phosphate on the ATP bonding to the new molecule?
Any help would be appreciated. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/ehx7j9/eli5_how_does_the_hydrolysis_of_atp_actually/ | {
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"Mmm, so ATP is a highly unstable molecule so a natural decomposition would just waste energy as heat. This heat is 'wasted energy' since it is unable to do work.\n\nIn metabolism ATP's highly energetic decomposition is used to make certain reactions more favorable through reaction coupling. In glycolysis this is achieved by giving the extra phosphate to glucose to turn it into an intermediary. This intermediary changes the shape of the glucose portion of the molecule so that enzymes can interact with it to turn it into fructose.\n\n[visual guide.](_URL_0_)",
"Atp doesn't actually give energy, it drives equalibrium. ATP is like two people who hate each other being forced to sit next to each other on a bus. Each protien allows ATP to separate by moving other passengers on the bus. Some protiens make room for ATP to separate by getting other passengers to sit together, other times by splitting up passengers, and sometimes by convincing them that they should just leave the bus entirely so there are more empty seats. \n\nBecause atp is less stable than adp and a free phosphate, any reaction that can be coupled with this dissociation can be sped up or even forced uphill, energy-wise. \n\nI've been told this following explanation is wrong by my orgo prof, but I'm pretty sure it's a good analogy anyways: imagine a protien like a spring: when atp binds, it causes the spring to flex (i.e. high potential energy). This bound/flexed protien now has an active site that will fit the substrate. When the substrate binds, however, it causes the protein to contort in such a way as it puts strain on the phosphate bond of atp, causing it to break off and release adp and Pi. Now, the spring is no longer supported and it flexes back, converting it's potential energy into kinetic energy and causing the reaction to occur at the same time.",
"My biochem text discusses phosphorylation using the concept of \"group transfer potential\", which is really another way of talking about which phosphorylated compounds are higher or lower in free energy. If these explanations don't satisfy you, try searching on that phrase.\n\nThe tri-phosphate of ATP consists of several negatively-charged phosphate groups bonded together. Because these negative phosphate groups repel each other, they are substantially higher in energy when bonded together than if they were hydrolyzed and separated. The electrostatic repulsion is a large part of makes ATP a high-energy molecule.\n\nThat explains why ATP can usually pass a phosphate onto other molecules, but not necessarily why doing so \"energizes\" the other molecules. For some other molecules, part of that rise in free energy comes from electrostatic repulsion, just weaker than that within ATP. For other molecules, the higher free energy isn't due to electrostatic repulsion strictly. An example is phosphoenolpyruvate (PEP), which is formed near the end of glycolysis. PEP is a relatively unstable chemical because it is an enol, with a C=C \ndouble bond adjacent to an alcohol. The alternative to an enol is a ketone, which has a C=O instead. Look up \"keto-enol tautomerization\" if you want more rationalization as to why the ketone is more stable. PEP can't form a ketone until it gets rid of it's phosphate, so when it does get rid of its phosphate, the enol can become a ketone which is much lower in free energy. This allows PEP to actually phosphorylated ADP, so it's a better phosphate donor than even ATP is."
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2lqdbn | why isn't 'being a qualified scientist' one of the requirements for a job as chairman of the committee of science and space (example: ted cruz)? | Also relevant: Being an educator on an education committee, a doctor on a health committee, etc. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2lqdbn/eli5_why_isnt_being_a_qualified_scientist_one_of/ | {
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"Because there aren't enough scientists/doctors/teachers in Congress to make that workable.",
"I have heard the argument that you have to have both points of view, that it isn't fair to only have scientists ona science committee. Because, you know, having idiots there to deny facts and obfuscate scientific discussion with idiocy is vital to making good decisions. \n",
"Because the state they are from matters more, along with seniority. Cruz being from Texas means he can turn around and bring lots of money to his state to make himself look good. Also NASA's Johnson Space Center being in Texas means he has a vested interest in the subject and keeping those jobs in Texas and funding present. ",
"tl;dr the requirement isn't feasible, wouldn't solve the (legitimate) problem, would cause other problems.\n\n--------------\n\nFirst, his job is Senator. There *are* requirements for that job. I'm not merely being pedantic, one reason to have requirements for the job of Senator is to elect people whose judgment you trust. Which brings us to:\n\nOn a practical (and general) level, the Senate gets to make its own rules about how they operate. Adding a rule like you're suggesting would add another layer of bureaucracy; it would be substituting rigid rules for the judgment of the person that you elected *literally to exercise judgment*. \n\nMore practical problems: there are currently 92 committees in the Senate. There are 100 Senators. Words like \"qualified\" and \"educator\" and \"scientist\" are difficult to define appropriately. Pretending that we could, the background of the 100 Senators don't nicely line up with the 92 spots. Pretending that they did, that doesn't mean that they're the best candidate to be chairperson. \n\nPretending all practical problems don't exist: Congress exists to create laws. They don't exist to do medical research or serve as an ad-hoc braintrust for NASA to get advice from when there's a problem with the Mars rover or whatever. \n\nI want my Senator to write good laws and to write them well. If someone writes shitty laws then it's little consolation that they *could* have taught 10th grade algebra, or that they *could* have performed heart surgery. Both of those jobs are really important! But I didn't hire them for those jobs; I hired them for the job of Senator.\n\nIf I want someone to write laws about heart surgery then I want someone **to write laws about it** not to perform it. Yes, in order to effectively write laws they do need to be informed! And having a background in something can help one be informed. But having a personal background in a subject doesn't mean that you're:\n\n* Sufficiently informed\n* The best person to write laws\n* The best person to write laws about it\n* The best person to chair a Senate committee about it\n\ntl;dr the requirement isn't feasible, wouldn't solve the (legitimate) problem, would cause other problems."
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6fzbas | why does ibm watson have so many commercials? (who is the target?) | [deleted] | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/6fzbas/eli5_why_does_ibm_watson_have_so_many_commercials/ | {
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"It is mostly about branding *getting their name out there repeatedly over and over - \n\nso when you think of the best possible soda - Coke or Pepsi pops in your head.\n\nWhen you think of fast food - boom you think of mcdonalds or burger king\n\nWhen you think of getting an alternative taxi via cell phone - you think of uber or Lyft\n\nand they are trying to convince you that when you think of the\npossible database in the world - you automatically think of IBM WATSON\n\n-- as for who are they trying to get to buy the product - if they are really getting customers from running ads in primetime - they are likely looking for executives in major companies who make decisions what company they will use for their best possible computer based database in the world - boom they will think of IBM Watson. If you think of it - they may pay $50-100K to run the commercial during the big game - but if it results in getting a contract with a major company worth millions of dollars - it was a good investment.\n\nTLDR - they do it for branding and very expensive contracts with big companies"
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90m5ve | how do nighttime rainbows function? | p.s. didn't know it was a thing till today. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/90m5ve/eli5_how_do_nighttime_rainbows_function/ | {
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"A moonbow (also known as a lunar rainbow or white rainbow), is a rainbow produced by moonlight rather than sunlight. Other than the difference in light source, its formation is exactly the same as for a solar rainbow: It is caused by the refraction of light in many water droplets, such as a rain shower or a waterfall, and is always positioned in the opposite part of the sky from the moon relative to the observer.\n\nMoonbows are much fainter than solar rainbows, due to the smaller amount of light reflected from the surface of the moon. Because the light is usually too faint to excite the cone color receptors in human eyes, it is difficult for the human eye to discern colors in a moonbow. As a result, a moonbow often appears to be white. \n\n[Wikipedia ](_URL_0_) ",
"Same way as rainbows, just light is being reflected off of the moon. Look up night rainbows. ",
"The sunlight reflecting off the moon can also produce a rainbow if similar conditions are met.\n\nYou'll need a bright near-full moon to do it and it will be very faint, but it's possible."
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5dmmg8 | what is the science behind cryogenically freezing someone? is there any real hope that a cryogenically frozen person will be revived? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5dmmg8/eli5_what_is_the_science_behind_cryogenically/ | {
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"The science right now says that if you get cryogenically frozen, it will kill you (if you weren't dead already) and rupture your cells (including brain cells) so that there's absolutely no hope whatsoever of reviving you. \n\nPeople are *hoping* that we'll one day find a way to repair these ruptured cells. ",
"A follow up question, who takes care of the bodies while they're frozen? I'd imagine they cannot thaw, so they need constant supervision. \n\nEdit 1: TIL, [Cryonics and cryogenics aren't the same thing!](_URL_0_) \"... cryogenics, which deals with extremely low temperatures, has no connection with cryonics, the belief that a person’s body or body parts can be frozen at death, stored in a cryogenic vessel, and later brought back to life.\"\n\nEdit 2: Thanks everyone for such a wonderful discussion and round of explanations!!!",
"The \"hope\" is that you really don't know what will happen in the future regarding new technologies. Anything can be possible. Or at least I like to think that way",
"No hope. Every single cell is burst when freezing and the body becomes a big, mixed up soup when thawed. \n\n",
"There's one more aspect to this. Your blood is replaced by a substance that doesn't expand much (or at all?) when frozen to minimize the destruction of cells due to water expansion.",
"The idea behind is that by preserving the body as best we can you'll be able to be revived in the future. \n\nThis is of course a gamble, but a gamble some people are willing to take.",
"Its incredibly unlikely. Not to mention that in the future, why would someone actually put tonnes of money into resuscitating some randomer?",
"We can freeze cells now but they aren't organized tissues, just cells lines (immortal) and I'm not too sure if primary cells and be frozen or if there really is a point if they aren't immortal. When you freeze cells you have to give them some kind of broth that is rich in all the things needed to survive. You also need a good drying agent to pull all the water out of the cells so you don't get destroy the cells from the expansion of water when it freezes. Typically Dimethyl sulfoxide (DMSO) is used. The problem is DMSO is very toxic so you got to make sure you don't have too much DMSO in solution. I've mostly have used animal cell lines so when preparing a sample for cryopreservation I would use 90% Fetal Bovine Serum (FBS) and 10% DMSO. In human cell lines I'm not too sure if you can use FBS for culturing, at least you can't when used for biologics. The issue with freezing cells is it's very stressful and and not all will survive, enough will survive to propagate them again. Freezing an actual human with all the different cell and tissue types might be a problem since they may have different thresholds for how much of a beating they can take and since not all the cells will survive the freezing and thawing process the person might die. Even if 10% of all your cells die that could be a big problem. It's also really difficult to instantly provide all of the essential nutrients to all your cells cell lines are in direct contact with the culture medium. The DMSO that was used to dry your cells also needs to be removed from the frozen cells since it'll kill them and doing that in tissues will be more difficult. \n\n**TL;DR** It's probably not possible to cryopreserve an organism of any type due to the shock and methods we currently have.\n\nHope I didn't fuck anything up with my explanation.\n\n",
"Edit: Jeez I didnt expect this to get so many replies, I don't think I ve replied to anything in this sub reddit before so I tried to make my point contrite. I ll try and answer people responses as best I can. \n\n4th year molecular bioloigist, neuropsychology major. \n\nThe creation of stasis, tupour, or suspended animation in humans is a pet hobby of mine. Cryogenics suffers from some pretty big obstacles like not being able to instantly freeze every tissue of a person, have that tissue not be damaged from the process/result (eg. Crystalization and cell lysis(death)), and not being able to thaw a person instantly. So far this has proven unfeasable with current technology. \n\nWe do use therapeutic hypothermia to induce states of decreased systemic metabolism for open heart surgery. There is also induced stasis/suspended animation via H2S gas exposure. I d say that Mark B Roth is the leader in the human stasis field at this time and you can watch his ted talk here. \n\n_URL_2_\n\nHope that helps, \n\nEdit: grammar and spelling\n\nEdits and responses: \nLink to Roth Labs and some of their publications\n_URL_0_\n\n > First, the field of cryonics (\"freezing\" \"dead\" people) is related to but distinct from cryogenics (the study of really cold things in general) \nCorrect, I fell victim to poor writing and the way the question was worded, thank you for the clarity \n\n > Do we know if the potential exists for indefinite suspended animation using this procedure? I would assume the microbes inhabiting your body would also need to be deanimated so as not to become positively unbalanced? \n\nI m not aware of any studies that have delved into this as of yet, the purpose of the suspended animation that is currently being focused on is to address acute medical conditions (traumas, strokes etc). I dont know about the efficacy of this for long term. \n\n > I don't see the \"not being able to thaw a person instantly\" part as an issue. After all, we're assuming a far more advanced level of technology in the future before a person will be thawed, and we have to imagine that at some point that problem will be solved. \n\nFair enough, I d personally like to have the freezing side of things and thawing sorted out and then gamble on the medicine improving sometime in the future. It be real sad if they cured your disorder but were unable to thaw you. \n\n > You mentioned not being able to instantly freeze/thaw a person as a problem. Sorry if this is a retarded question, but does this mean it could theoretically be done to some much smaller organism, where it's take less time to freeze/thaw it's entire body? \n\nThe largest animal I'm aware of being suspended is a pig, they lacerated/damaged the arteries, left them for 3 hours, came back and fixed the wounds and then revived the animals \n\n_URL_1_\n\n > Is \"tupour\" really a term or did you mean \"torpor\"? When I google \"tupour\" the only results are in French...\n \nCanadian here, Torpor is correct, we have a viscious habit of adding \"u\" to words with \"-or\" \nSee: Colour, armour etc. \n\n > wait... what? I thought H2S screwed up the mitochondria in a manner similar to how cyanide does, and therefore was quite toxic. How can it be used for suspended animation? \n\nThe gist of this is that cyanide binds covalently (a permanent chemical alteration) and H2S is just a competitive antagonist (competes with Oxygen for the same transporters/receptors). The are both cellular asphyxiants though, just that you can reverse the equilibrium of H2S with something like a high volume of Oxygen. \n\n > What's the difference if it happens instantly versus over a slightly longer time? \n\nThe Body parts do not exist in a vacuum, homeostasis (the body's basic rate of metabolism and function) requires many cascades and pathways to operate in parallel to function. \nEg. Having a thawed limb does you no good if the brain and the heart are not thawed as you will have no regulation or perfusion of nutrients. ",
"I look at it this way, they are basically donating their bodies to science. Cryogenics isn't going away anytime soon and who knows what the future holds. At the very least, these people who are being frozen are contributing to an emerging scientific field. Worst case scenario, they just stay dead, so.... really nothing to lose by hoping.",
"It's a shame there are so many bad answers to this.\n\nThe actual science is as follows : the current 3 or so cryogenic companies try to use chemical agents to inhibit ice formation. Because they have to wait until the patient is legally dead at the moment, this is not as effective as it could be. \n\n The _specific_ technology needed to revive someone if it's possible would probably need to be a close to atom by atom scan. This is actually very close to possible today, no future technology is needed, but of course with today's methods it would be incredibly expensive. \n\nToday's method is a multi-electron beam microscope and a slicing machine. 80 parallel beam models exist today, an estimate of what it would take that I read somewhere estimate you'd need 1000 modules with 1000 beams each for several years. The brain would have to be sliced with automatic tape collecting ultra-microtomes which generate 50nm slices.\n\nSo now in a massive pile of hard drives somewhere is an atom-by atom scan of a brain. What do you do now? Well, you'd need to do a whole bunch of research so you actually know how every single synapse performs electrically, and how precisely the mechanisms for learning work. This neuroscience knowledge is presently incomplete but it isn't science fiction, it could be found with today's methods and technology.\n\nYou would build a small mountain worth of specially designed ASIC processors that emulate your neural model. They would be similar in concept to google's tensor processors or IBM's neural simulation chips. Or you could use GPUs but you'd need a lot more. \n\nYou'd then simulate the person's brain and build them a virtual environment or a robot body to live with.\n\nIt's reasonable to think that while the above would cost something around Bill Gate's entire fortune, once it has been done once, it could be made far, far cheaper. We know a human brain can be developed in nature with a modest amount of energy and raw materials so ultimately this process could be done for everyone if it works.\n\nWhat scientific answers exist that indicate it *won't* work?\n\nI know of none if the brain were preserved well. No credible scientist has evidence for \"souls\" or \"magic\" used by the human brain. If the human brain is a physical system and you have the pattern for the system, you can emulate it and it will act very close to the original. Some of the cryonics patients frozen today may have too much damage for a molecular scan to be able to reconstruct their original synapse structure, however. \n\nThis is what makes cryonics a gamble today, because the freezing does a lot of damage. A second issue is that \"waking up\" as a computer simulation of yourself is different from waking up as yourself, even if it seems exactly the same. The original you had to be torn apart in order to copy it.\n\n",
"The [Alcor Life Extension Foundation](_URL_0_) in Scottsdale, AZ will freeze you in a shiny metal tank in a way that they hope will preserve your brain so it can be transplanted or uploaded later. Their website is actually pretty informative.",
"The best summation I've found of the current state of cryonics comes from the RationalWiki entry (worth a read in full to convince you not to bother putting yourself on ice just yet):\n\n\"Cryonics for dead humans currently consists of a ritual that many find reminiscent of those performed by practitioners of the world's major religions:\n\n1. Freeze the body.\n\n2. Wait for a miracle.\"\n\n_URL_0_\n \n",
"ELI5? Ok, you know how frozen vegetables are mushy and don't taste quite the same as fresh vegetables? Now imagine that same thing happening to your dead brain.\n\nThat's the reality behind cryonics.",
"Only dead people are frozen - so anyone having it done is doing based on their religious faith that someday Science will cure death itself and be able to resurrect dead people.\n\nPeople talk about \"freezing someone with cancer until there's a cure for cancer.\" Nope, you'd have to cure DEATH ITSELF.\n\nDo you freeze a person that bled to death until we can cure bleeding to death? We can give blood transfusions right now! But once a person is DEAD, it doesn't matter anymore. You're freezing them until we can bring dead people back to life.\n\nThey're banking on the day coming when all humans are able to live forever thanks for the power of Science.",
"It is a scam. Freezing you damages you in a way that prevents a possible revive. We have no clue if we can fix the damage or revive you.\n\nAdditionally, they only freeze people who are pronounced legally dead. Legally it is just a body disposal option, and they don't have to ever attempt to revive you, and they likely won't because they can't and will likely never be able to. They also might not even be around in 100 years (the company).\n\nThere is zero regulation and it is just a way for them to collect a life insurance policy you had to take out on yourself.\n\nThey are selling science that doesn't exist and won't even come close to existing for hundreds of years. By the time it does exist, if your body is still frozen somewhere, it will likely turn out you weren't frozen in the correct way they need to unfreeze and revive you. ",
"This is done after your dead so I don't think you will be feeling it anyways.\n\nBasically you can get your body frozen or just your head (cheaper) with the hope that one day we will have the tech to regrow the rest of the body and revive someone from cryo without any cellular damage.\n\nI'm pretty sure the company doing it is just taking people's money to throw their corpse/head into liquid nitrogen. There's no way for the patient to ever take them to court if they never get woken from cryo.\n\nThat being said, id rather drop 100 grand on a scam with the hope of one day being revived (no matter how low the chance), then just bury myself in the dirt to become compost.",
"Short version is that the key concept here is \"Information Theoretic death\"\n\nThe idea/goal is to prevent irreversible loss of the brain information that makes you, well, you. So yes, the process does plenty of damage, but the question is: in principle, could one, with sufficient neuroscience/etc/etc, reconstruct the brain patterns from what's been preserved?\n\nCould the self, the actual stuff that makes the person, themselves, be recovered? The idea/hope is that cryo may help prevent the loss of brain information to entropy. That doesn't mean that it doesn't cause damage, but that the damage may be the sort that the information can still be recovered from.\n\n\"Information Theoretic Death\" is basically defined as the final irreversable death, where the brain information is lost to entropy. The goal is to try to prevent that, and then leave it to future tech to try to work out how to recover that information into a more useful form. (how to repair the damage directly, or to scan and upload the mind from the preserved brain, or or or or or...)",
"Summary: None, don't do it, it's a terrible idea.\n\n_URL_0_",
"Physiologist here, who, about 15 years ago, was curious about the \"science\" of cryogenically freezing someone and read a good deal of the current scientific literature.\n\nFirst, there are real, outstanding, scientists who study the physiology of cooling whole organs and organisms with the intend of understanding how we can use cooling to prevent/limit the damage done to tissue when it experiences hypoxia (when a tissue or animal is deprived of normal levels of oxygen). This research has led to many important medical treatments - such as the use of hypothermia in patients undergoing surgery requiring cardiopulmonary bypass (a machine that oxygenates blood during heart surgery) and in head/spine injuries. Other import work is currently being done to understand how we might use hypothermia to increase the time a human organ can survive outside of the body for transplantation surgery.\n\nThere is, however, very little good science on freezing an entire person with the aim of bringing the person back to life many years later. Most of the \"science\" done in this area is by shady scientists in 3rd world countries (including many former Soviet Union Eastern European countries). \n\nThere are many different companies that will take your money (and a lot of it) to cryogenically freeze your body and maintain your body in liquid nitrogen. They all use different protocols for freezing the body and different formulations of cryogenic solutions that are supposed to limit the damage done to your cells/tissues by freezing. Most of the \"science\" is related to histology studies of the frozen tissue (microscope studies) that show that the tissue still has substantial damage caused by ice crystals. \n\nNone of these companies has solved the problem of how to fix the damage that ice crystals cause to your cells/tissues. All of these companies explain away this fact by making vague statements that, of course, this problem will somehow be solved in the future. \n\nIt remains, however, to be proven that anyone currently frozen can be brought back to life. All current scientific evidence points strongly to the contrary - and that most people currently cryogenically frozen will never have a chance of being brought back to life.\n\n",
"I've always been fascinated by this, that and cyborg bodies, both are great in science fiction, but in the real world are a big more.... horrible. If you could be like Phillip J. Fry and hop in a tube and be frozen instantly and unfrozen instantly it would be great. But the fact that you have to die, and that revival is impossible at the current tech level is a bit scary. \n\nBut look back 100 years, WWI was raging and we were using primitive tanks and airplanes. Now we have drones and super jets that can get across the globe in a matter of hours. ",
"Everyone always focuses on the biological side, what about the legal side? Say a person gets frozen at 14, and thawed out at 21. Can they vote? Can they drink? Can their parents charge them rent? These questions are much more important than, \"how will we successfully cryo people?\" /s\nSource: am feed store lawyer (like a shade tree mechanic, but I didn't go to school for longer) ",
"One important aspect many people do not know about cryonics is they don't actually freeze their patients. They use a process called *vitrification*. With this process they use a special cooling technique along with chemicals to turn the water into a viscus slurry, much like glass or molasses. They continue to cool this liquid until it appears solid, but lacks the crystalline structure of solid water. This prevents several problems that would by caused by just freezing the water/patient outright.\n\nThis vitrification process is done as close to clinical death as possible in hopes to keep as much of the original brain structure as we can. With the brain intact (and sufficiently advanced technology) it is theoretically possible to revive a patient with full memory and personality.\n\nThe chances of a person actually being revived is difficult to say due to the fact the future is hard to predict. Everything that makes a person who they are is still sitting there, \"frozen in time\". Now it's just a question of whether or not we can ever take that part of the person and find a way to give it some sort of life again without destroying it in the process.",
"When cells are frozen, the water in them expands. This kills the cell.\n\nThe hole is the future will have technology that can recover this damage, then cure the person, then resuscitate the meat popsicle. ",
"_URL_0_\n\nI say there is hope since there is a living frog that can do it. that shows there is possibility at least in my pea sized brain lol. it's just coming up with how",
"I'm not a conspiracy theorist or anything but are the places where these cryogenic tanks are stored hardened? Meaning protected against EMP's. because let's be real, 1000 years is a LONG time and anything can happen.",
"Frozen is not really the correct term. Vitrification is the correct scientific term. Using anti freezing chemicals and liquid nitrogen, the person who can't be saved by current medical technology is super cooled in hopes of suspending brain death until the technology exists where you could be revived. Alcor, one of the biggest proponents of Cryo Vitrification, has a website with a great FAQ on the process if you are interested. Another good write up on the subject was done at _URL_0_ titled \"why cryonics makes sense\". It's a really good read, I highly recommend it. The one creepy part I don't like about the idea of Cryo preservation is that they remove all your teeth in the process.... Makes my skin crawl.",
"I heard from a biology teacher that when they freeze your body the brain is pretty much fucked, that it'd basically be soup when thawed out. We would need a lot more breakthroughs than a cure for cancer to bring back the girl who was frozen recently.",
"The top post is very good, but I feel the need to add that is is all currently impossible due to how toxic the cryopreservarive agents we have are. I am a third year chemical engineering student involved in cryopreservation research and my research professor is working on a model to minimize toxicity effects for a simple tissue like cartilage. We can't even do that yet, let alone a whole organ or a body. So while it sounds really simple, the devil is in the details. ",
"Has there been anyone frozen that wants to be \"reborn\" at a specific date , or do they all just want to be thawed out when the science is able to save them ?",
"Sperm cells can be frozen for extended periods of time and then thawed to use. \nPeople hope one day that the same can be done with human bodies.",
"The way that the brain stores information (memories, behavior, etc) only works for living brain cells. Once those cells die (or freeze) your personality is gone for good.",
"[Here's a really excellent article about it](_URL_2_)\n\nBasically, cold temps cause your metabolism to slow down. We use cold liquids on patients whose heart stops, it prevents brain damage. This is called hypothermia protocols.\n\nCryogenics basically takes that a step further.\n\nOther people have talked about the process, I'll talk a little bit more about the science. \n\nThe use a cryopreservation liquid that vitrifies when cold. So when water freezes, it expands because it crystallizes. This is bad, because that will destroy organs and, most importantly, your brain. This cryopreservation liquid doesn't crystalize, it just becomes a solid. This is good, because it will preserve organs and not destroy them like water does.\n\nAs for if it's viable, currently we can't revive anyone is cryo. However, we already use cryonics in medicine, pretty commonly. We store rare blood types in cold storage, I think we store sperm that way, and we can even store small stuff like blood vessels.\n\nRecently however, we've moved further. [This person](_URL_1_) succesfuly preserved the brain of a small mamal. \n\nWe have also [preserved a rabbit's kidney and returned it to the rabbit.](_URL_0_)\n\nAlthough my thoughts are, I'm already dead, why not?",
"The goal of cryonics in fiction, as portrayed in popular culture (cartoons, movies) is often to be able to \"thaw out\" a corpsicle and miraculously bring it back to life and health (see Encino Man). The aim in reality is to preserve the *information* that is represented in the arrangement of the cells and molecules in the brain, which constitutes their identity, and from which their consciousness might someday be reassembled or simulated. Cryonics views death not as a discrete state change, so much as a gradual process of entropy in which the information constituting a person's consciousness, as represented by the arrangement of molecules and cells in the brain, is destroyed through cellular decomposition, disintegration, and transformation. In that sense, death isn't a switch between two states \"alive\" and \"dead\", so much as a rheostat, where information is progressively lost through decay. One is well and truly dead when there is no longer enough information (in an information-theoretical sense) in what remains of their brain tissue to reconstitute anything resembling a consciousness. So, cryonics halts the disintegration of that organ until such a time as technology might allow its information to be recovered and used to reconstitute the consciousness of the individual in a new physical medium. That medium might be the original organism that gave rise to the consciousness, restored through technology that we do not currently possess (such as MEMs that can perform cellular repair), a simulated organism running on computer hardware, or a synthetic host designed to house the consciousness. There are many potential definitions of \"revival\", in any case. Success in any of them could result in the creation of something or someone approximating the consciousness of the deceased.",
"As far as i understand human biology and science there isnt much hope. They put chemicals in you to help preserve organs and the body/brain but you are still completely brain dead. I do not believe there would be a way to revive them in the future not without very severe brain damage.\n\nHowever i do think cryogenically freezing and reviving may be possible in the future but i think the proccess of preserving has to improve as well as the process of reviving.",
"So say that you take out a life insurance policy and sign a contract with a cryonics operation. You get somewhat successfully preserved, and eventually Science! figures out how to undo the damage and thaw you back to life.\n\nWhat kind of stipulations are included in the contract to determine whether/when you get brought back? Cost threshold? Risk? Can you sue if the company chooses a budget thawing operation that leaves you with extensive neurological damage?",
"We can cryofreeze cell lines for decades with pretty good genetic integrity, also spinal cord injury victims show significantly better chances of improvement if the affected area is cryo forzen within an hour of injury. Additionally, patients can have tissues cryofrozen to give doctors time to treat a disease.\n\n\nBasically, freezing slows down the cellular clock. As to how slow? And how to go about reanimating? We have no idea.\n\nYour second questions- maintenance in those facilities is easy, they just have to make sure the system gets a constant flow of liquid nitrogen, and I'm sure there is monitoring for that.\n\nSource: molecular biologist, I used to refill the nitrogen in the cell banks each week.",
"Easy explanation: \n \n1) Realize the most primal instinct in humans is fear of death \n2) Give them hope they won't die \n3) Charge a shittonne for the illusion \n4) Laugh at your profits and their stupidity",
"If you froze a human, all the liquid water in their body would eventually hit its freezing point and crystallize into a solid. That wouldn’t be good—first, water ice takes up about 9% more volume than water liquid, so it would expand and badly damage tissue, and second, the sharp ice crystals would slice through cell membranes and other tissue around it.\n\nSo to avoid that catastrophic liquid-to-solid state change, cryonics technicians do something cool—they perform surgery through the chest and hook the major arteries up to tubes which pump all the blood out of the body, replacing it with a “cryoprotectant solution,” otherwise known as medical grade anti-freeze. This does two important things: it replaces 60% of the water in the body’s cells, and it lowers the freezing point of what liquid is left. The result, when done perfectly, is that no freezing happens in the body. Instead, as they chill your body down and down over the next three hours, it hits -124ºC, a key point called the “glass transition temperature” when the body’s liquid stays amorphous but rises so high in viscosity that no molecule can budge. You’re officially an amorphous solid, like glass—i.e. you’re vitrified.\n\nWith no molecule movement, all chemical activity in your body comes to a halt. Biological time is stopped. You’re on pause.\n\nCopy pasted from _URL_0_\n",
"I have a friend who works for _URL_0_ in Arizona and she let me touch the stainless steel tank that holds the frozen head of baseball legend Ted Williams. \n\nMost of their customers just freeze their head upon dying rather than their whole body. It's cheaper. Most of their customers pay for their lifetime support with a simple life insurance policy listing Alcor Life Extension Foundation as the beneficiary. They have a huge waiting list of people who are paying future customers. You need reservations. I'm serious. ",
"The process has been well explained in the comments but I can't see much on the hope of being revived. I'm no expert and I'm recalling info from a documentary that I can't remember the name of. It is my understanding that whilst the cells of the body can be well preserved, the person is always dead and would essentially need a cure for death. I think the theory goes that they'd use some hyper-advanced futuristic defibrillator to restart their heart and brain and breathing etc. 3 major problems:\n\n1. Reversing the entire process and restoring their body after removing all the foreign chemicals\n\n2. Curing any diseases they may have had before death can reoccur or reverse any cause of death\n\n3. Curing death\n\nWe currently only have a way to restart someone's heart and even then a tiny viable time frame to do so in. We also don't have precise ways to control the brain or stimulate activity in highly specific ways; one would need to be able to be so fine as to create breathing as opposed to just a spasm",
"Imagine if we had the bodies of people who froze themselves 300 years ago around today. Sure, it's likely we'd be able to cure whatever disease they'd tried to escape, but why would we want to? Such a person would merely be a historic novelty, someone once rich in the long distant past. Why would the people of the future want to revive us in a world potentially overpopulated and struggling for resources?",
"Are we more likely to be able to live on through cryonics or are we more likely to be able to download our brain and live in a simulation?",
"im confused, you have to die? so how do you get another life when you wake up. or, if you don't die but just get a \"pause\" - you still have your same consciouness and memories when you wake up 200 years later?",
"It's mostly science fiction/a scam. It's illegal to freeze people alive since it would in fact kill them and therefore essentially be murder, so people pay to be frozen after death. People use to be straight up thrown into a freezer which, as anyone who has left food in a freezer knows, is not viable for long term storage. Then a few preservation techniques were developed and your corpse is basically embalmed and then stuck in a freezer so your cells wont break down from the cold. You're still dead, just now full of preservatives.\n\nThe idea being that some time in the future, there will be a process to reverse the preservation process, unfuck your body, and then some how literally bring you back to life. \n\nWhen you sign up for cyrogenics you are basically paying for a very expensive burial package in which your whole body is preserved. Think of it as a kind of modern mummification.",
"Is it fair to assume that if a person is frozen and then successfully revived that the time between dieing and opening their eyes again will pass like the blink of an eye?",
"Can a two term president cryogenically freeze his head and them be stitched to a different body in the future so he could run for a third term? ",
"Yay I know a bit about this one! We are able to cryogenically freeze a few human tissues without serious issue basically because the tissues:\n\n1) can survive the dehydration process necessary to prevent ice crystal forming and bursting cells.\n\n2) are thin / small enough that freezing happens almost instantly. \n\nThe fertility clinic I work at freezes embryos on a routine basis by dehydrating them and dropping them straight into liquid nitrogen because it's easy and has very few side effects that we've found. One of the PHDs is working on a way to freeze entire ovaries, and is having a much harder time because they don't fit the criteria above. The problem gets drastically tougher when trying to freeze an entire person because dehydrating their cells all at once and freezing them instantly is something we just haven't developed yet. Also, tissues can survive if a few cells die, and that's not something you can risk with nerve cells and the brain. ",
"Seems to me that cyronics is just the modern form of mummification that the egyptians were into. Instead, technology is our god and eternal life is to be awoken in the future.",
"Long post, hopefully helpful! For me, the process is quite interesting, as I deal with this on a much shorter time frame frequently as a cardiac anesthesiologist. One of the most interesting things we do in medicine is something called cardiopulmonary bypass, where you take all the blood out of the heart and lungs, put it through an oxygenator, and then pump it back through the aorta (biggest artery in your body) to keep the rest of the body alive while the surgeon operates on the heart, or major vessels of the lungs. \n\nNormally, you run the cardiopulmonary bypass machine constantly, but in some cases, the surgeon actually has to turn off the pump because they are operating on the root of the aorta. To do this, you literally 1) arrest the heart (AKA induce asystole, stop the heart beat), 2) cool the patient down to 18-20 degrees celsius (normal body temp 37 celsius), and then turn off the pump (this is called deep hypothermic circulatory arrest). You can do this for somewhere between 45-90 minutes before you start to see brain damage. So....in these cases, you have NO HEART BEAT, NO BLOOD FLOW, and you are CLINICALLY DEAD. When the procedure is complete, the heart is restarted, the cardiopulmonary bypass machine is restarted, and you literally bring the patient \"back to life\" and finish the case. \n\nEven 50-60 years ago (and more recent for pediatric patients), it was considered impossible to operate on a beating heart, and everyone who tried to do so was almost universally ridiculed for their efforts. \n\nApplying that to cryogenics, they do something similar to deep hypothermic circulatory arrest. They perform a process called vitrification, which is different from freezing a patient. The problem with freezing a body, which is mostly made up of water, is that you destroy the underlying cellular architecture, making it impossible to recover upon rewarming. The vitrification process is like embalming, where they access the major vessels of your body, empty out the blood, and replace it with a fluid that will not freeze like water freezes. Instead, you can replace the entire blood volume with this fluid, place the body (or head) into liquid nitrogen, thereby preserving the structure. As to how long this preservation process is viable, no one really knows. They have successfully re-implanted a vitrified kidney into a rabbit and have it function again. As to how this process would work with human organs, most importantly the brain, is anyone's guess. \n\nThat being said, it is an interesting field with a lot of science behind it. It just sounds crazy right now. Kind of like CPR would have sounded crazy 100 years ago....\n\nTL;DR - Hard to say, but none of us will be around to confirm or deny its efficacy unless we successfully come back ourselves. ",
"As you can tell by the comments here, lots of the people answering this question need an ELI5 themselves. Cryonics is not a freezing process. And it's not a 'scam' (the organizations are all nonprofits, for instance).\n\nOregon Cryo actually has a very balanced and straightforward explanation of the procedures, possibilities and pitfalls on their website. See here: _URL_0_",
"One day, when we have the technology to rebuild every single cell-wall in the body, no doubt ruptured by the freezing, it'll be feasible-probably, maybe?",
"I too, listened to NPR this morning. I thought their guest was knowledgeable, but I wished he'd addressed the idea behind reviving bodies that were preserved prior to the technology maturing (as in, those bodies frozen now or earlier). It seems that bodies frozen before getting the macro scale issues solved would damage the tissues (and probably kill the subject).",
"Hope? There is always hope. There just isn't any possibility. ",
"Money. The science behind it is simply money. Anyone cryogenically frozen is as good as dead. The doctors know this. They also know family members will spend a lot of money on the off chance that their terminally ill family member can be saved via magical freezing process. So this exists, because people like money and people like hoping the best for their family.",
"In case you were asking about cryonics after all, the science behind it is mostly decision theory: it's way better than rotting, even if the absolute probability value is low.\n",
"I wonder what conditions have to be met to unfreeze someone. Like who gets unfrozen with unfreeze 1.0 and who gets to wait for the bugs to get worked out. \n\nIs there a contract on time? If 100 years pass and we haven't figured it out do you get dumped?\n\nDoes consciousness downloading in a virtual world constitute a fulfillment of being woken up?",
"To revive the current corpsesicles, you need to be able to fix a) whatever killed them, b) the added damage done when they were frozen and kept on ice and c) death. \n\nEven assuming the brain works in such a way that the data is stored 100% chemically and that the electrical impulses we measure with an EEG are just, you know, an accident and have nothing to do with thinking... it's still curing *death*. \n\nAnd no, that's not the same thing as reviving someone who's been technically dead for 3-4-5 minutes, this is like digging up a dead body and reanimating it. \n\nCan we do it some day? Maybe, if we become gods or very nearly. Is it within any kind of reasonable time frame that matters to someone being frozen today? Oh come on.",
"“ELI5: What is the science behind cryogenically freezing someone? Is there any real hope that a cryogenically frozen person will be revived?”\nIf recovering a complete entity is beyond current technology. Why not preserve a few cells, in the knowledge that future cloning is possible?\n",
"I think science is going to succeed. They brought back a rabbits brain, without damage. _URL_0_",
"I am a layman who has read much about human cryogenics. It works a bit like this, for some cases:\n\nThe person dies, and a team will begin working on the corpse, preparing it for freezing.\n\nThe person has to die *first*. As much as some people would like to be frozen *before* dying, to preserve as much as possible, this would be classified as murder, so it's a no-go.\n\nUsually, the team will cut off the head. Yes, that's right, they decapitate the corpse. Most people prefer to have *just* their head frozen, because it's cheaper. Some people prefer to have their whole bodies frozen, but that's far more expensive. Think of the difference in cost between freezing a bucket and freezing a whole coffin/casket.\n\n(Also, some people get their pets, or the heads of their pets, frozen when the pet dies, so they can be reunited in the future.)\n\nThe team will drain the bodily fluids, and replace these with an alcohol-based solution, which works similarly to antifreeze. This solution is designed to allow the body to be frozen below zero, without icicles forming inside the cells. Those icicles can tear the cells apart. This solution does have the side-effect of 'pickling' the body or head.\n\nThen, the body (or head thereof) is stored somewhere cold, and transported to a storage facility. As far as I know, the only cryogenic facilities available are in the United States and Russia.\n\nThe head or body is placed in a casket, which is placed in a freezing unit. If I remember correctly, these units are sometimes kept cool with liquid nitrogen.\n\nThe large sum of money that you pay for cryogenic storage/suspension is not solely for the cost of preparing or initial storage the body. Most of that money is put into a trust fund, which is used to keep the facility running. In other words, the interest on that money pays the bills to keep each body frozen.\n\nThe idea is that, at some unknown time in the future, medical science will have evolved enough to reverse the 'pickling' process, restore any lost 'brain data' (the state of neurons prior to death), cure any applicable problems, grow a new body, and 'reanimate' the person. The money in the trust fund is ultimately used to pay for this whole reanimation process.\n\nCan this 'brain data', such as memories and personality, ever be restored? Neurons, an important part of the brain's structure, tend to lose data (memories) quickly after losing blood supply (death). Technically speaking, they depolarise rapidly. Perhaps in the future neuron restoration technology will exist, permitting the complete recreation of the person's mind. (How? Perhaps there will exist a similar technology allowing medical doctors to determine the neuron's state prior to death and freezing, similar to the theory of how digital data can be extracted from a magnetic hard disk drive, even after it has been overwritten once or twice.)\n\nCryogenic facilities are generally run by people who themselves have much faith in the cryogenic process, and also plan on being cryogenically stored after death. As such, there is generally a hope that people who have faith in the system will also work to ensure the running of the system during their own lifetimes, and the foresight to ensure that the company is continued to be run by like-minded individuals and/or organisations.\n\nI sincerely hope that one day, a person who was once cyrogenically suspended and restored reads over this explanation, and says 'Wow! What a terrible attempt at explaining cryogenics...'",
"There is lots of science in freezing them, but very little in preventing cell damage due to the water in the cell expanding as it freezes and almost none in successfully reviving them.\n\nThe best summary for cryonics is that you are gambling on future medical advances that may or may not happen. No current technology can revive them.",
"According to a thing called \"The Information Theoretical Criterion of Death,\" everything that makes you into the person you are is information stored in your brain: memories, personality, emotional responses, mannerisms, and so on.\n\nIf that information is what makes up a person, that person dies when the information is irreversibly damaged: hence according to the ITCD, brain death is the important bit. Your brain can survive without oxygen for a short while, so even having your heart stopped is just that — a heart stopped. If we can get it pumping again, you'll remain very much alive. If your brain suffers massive anoxic damage during your cardiac arrest, you die.\n\nSince we are working with information, imagine the brain is a hard drive. Now, if you want to get rid of the information on a drive, it's usually not enough to format it — that only deletes the 'index' so to speak, of where everything on the drive is.\n\nIf you purposefully go and over-write every file on the drive with garbage data, even then it is not enough; clever forensic data-scientists can take your hard drive apart and use special microscopes to read your data off the drive still. Simply put there is a hidden history of data on the drive which is not used in normal operation — it's not even purposefully there, it's a consequence of how hard drives are made.\n\nIf you *really* want to destroy a hard disk, you take a blowtorch to it. Hard to read anything of a molten slag of plastic.\n\nWhich brings us back to brains. Going by ITCD, avoiding death is as simple as making sure the brain doesn't lose its information. Letting brain cells die due to lack of oxygen is a good way to do that — hence why we declare death when we cannot start people's hearts up: there's just nothing we can do.\n\nPutting people in the dirt will make the brain rot away entirely — similarly a good way of being sure one loses *all* the information. Even better is cremation: can't find any hint of brain information in a pile of ash, can you?\n\nSo, what are the *opposite* of good ways to loose all information in a brain? To start with, the best is probably to remain alive. Living people's brains don't tend to break down.\n\nBarring that, the brain is made of meat-like substances, and we all know that a frozen steak doesn't rot or go bad very quickly. So freezing a person upon death may be a good idea.\n\nNow, unfortunately, anybody who has repeatedly frozen and thawed delicate foods know that this gradually degrades them: re-frozen and re-thawed strawberries are disgustingly mushy.\n\nThis is because in the process of freezing, water crystallizes outside the cells, but not inside the cells. That the water solidifies outside the cells raises the concentration of electrolytes, which by osmosis forces water to pass out of the cells. This dries out the cells almost completely, killing them. Dead brain cells is lost information. Too bad.\n\nThis is where it gets sciency: to cryogenically freeze someone, the cryonicists first pump them full of cryoprotectants. These are chemicals that prevent ice crystals from forming, and allows the tissue to be safely cooled to a point where water freezes more like glass, rather than ice: with no crystals. This does not dry out the cells.\n\nNow there are some concerns about the process, and there is some information loss; but it is a heck of a lot less than anything else we have on hand at the moment.\n\nWill it work in the future? Can we bring people back to life? I don't know. But we have a better shot at it with cryonics than with cremation."
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"https://www.cryogenicsociety.org/cryonics/"
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"https://labs.fhcrc.org/roth/publications.html",
"http://journals.lww.com/annalsplasticsurgery/Abstract/2014/05000/Hydrogen_Sulfide_Mitigates_Reperfusion_Injury_in_a.20.aspx",
"http://www.ted.com/talks/mark_roth_suspended_animation"
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"https://www.alcor.org/"
],
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"http://rationalwiki.org/wiki/Cryonics"
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[],
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[],
[],
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"https://www.thisamericanlife.org/radio-archives/episode/354/mistakes-were-made/"
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"http://www.treehugger.com/natural-sciences/nature-blows-mind-arctic-frogs-come-back-life-after-being-frozen-video.html"
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[],
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"waitbutwhy.com"
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[],
[],
[],
[],
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"http://www.ibtimes.co.uk/cryogenically-frozen-rabbit-brain-returned-near-perfectly-preservation-1543083",
"http://ieet.org/index.php/IEET/more/prisco20160209",
"http://waitbutwhy.com/2016/03/cryonics.html"
],
[],
[],
[],
[],
[],
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"http://waitbutwhy.com/2016/03/cryonics.html"
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[],
[],
[],
[],
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"http://oregoncryo.com/aboutCryonics.html"
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[],
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[],
[],
[],
[],
[],
[],
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"http://www.dailymail.co.uk/sciencetech/article-3440262/The-brain-rabbit-cryogenically-frozen-brought-life-near-perfect-condition-contain-animal-s-long-term-memories.html"
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ktre2 | eili5: solipsism | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/ktre2/eili5_solipsism/ | {
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"I know I exist, but I'm not sure about you. \"Know\" used in the most literal and strict sense possible.",
"There are various versions of solipsism, but most simply it can be thought of as this: Nothing exists except for me and my mind. The entire world is merely a fabrication to keep my mind busy/entertained/whatever.\n\nThink of the movie the matrix, except there is no \"real world\" and you don't have a \"real body\" Nor is anyone else you encounter in the matrix real, they're all just programs/illusions. The difference being that instead of an outside entity setting all of this up, your mind is setting this up.\n\nWhen people aren't around me, they simply don't exist. Plain and simple. They may have memories of existing, but that is just part of the fabrication my mind has created. Everything is like this, if a tree falls in the forest, and I'm not around to hear it, then it makes no sound because it didn't exist and couldn't have fallen in the first place.",
"I know that my senses can play tricks on me - for example, when I dream I do not necessarily realize that it is a dream.\n\nThis raises a question. How can I trust the perceptions I have while awake are any more real than those dreams, or other hallucinations I may have due to hallucinogenic substances and/or metal illness? I could argue that I'm in the matrix, for example.\n\nThe answer is simply that I can't know - because my understanding of the world depends on my perceptions. Unless I state that the world I see, hear, smell and feel is real, the only thing I can know is that my mind exists.",
"No, maybe when you're older. ",
"TIL Solipsism is a friggin ridiculous theory. ",
"Solipsism is when....\n\nYou say to yourself: \"I think, therefore I am\" KA-BLAAM, you know you exist.\n\nSomeone else says \"I think, therefore I am\" KA-BLAAM, they know they exist.\n\nBut you say to yourself, \"So now I know I exist, but I can't know that other people exist, because I'm not them, and I can't speak for them, only myself\"\n\n\nSomeone else says, \"So now I know I exist, but I can't know that other people exist, because I'm not them, and I can't speak for them, only myself\"\n\nSo, in this world, everyone goes around knowing they themselves exist, but not knowing that other people exist.\n",
"Solipsism is the idea that you cannot prove that anything outside of the mind exists but you can however assume that your mind exists because if it didn't you would not be thinking about it in the first place. \n\nA problem with this however is that solipsism does not go all the way to it's logical conclusion which is that you can only be certain that your thoughts exist. \nSince you are not experiencing the process of the mind that generates your thoughts you just experience the thoughts themselves after they have been thought up you can not say for certain that even your mind exists as the possibility of your thoughts being externally generated is always present.\n\nDescarte should have said not \"I think therefore I am\" but \"There are thoughts\".",
"I know I exist, but I'm not sure about you. \"Know\" used in the most literal and strict sense possible.",
"There are various versions of solipsism, but most simply it can be thought of as this: Nothing exists except for me and my mind. The entire world is merely a fabrication to keep my mind busy/entertained/whatever.\n\nThink of the movie the matrix, except there is no \"real world\" and you don't have a \"real body\" Nor is anyone else you encounter in the matrix real, they're all just programs/illusions. The difference being that instead of an outside entity setting all of this up, your mind is setting this up.\n\nWhen people aren't around me, they simply don't exist. Plain and simple. They may have memories of existing, but that is just part of the fabrication my mind has created. Everything is like this, if a tree falls in the forest, and I'm not around to hear it, then it makes no sound because it didn't exist and couldn't have fallen in the first place.",
"I know that my senses can play tricks on me - for example, when I dream I do not necessarily realize that it is a dream.\n\nThis raises a question. How can I trust the perceptions I have while awake are any more real than those dreams, or other hallucinations I may have due to hallucinogenic substances and/or metal illness? I could argue that I'm in the matrix, for example.\n\nThe answer is simply that I can't know - because my understanding of the world depends on my perceptions. Unless I state that the world I see, hear, smell and feel is real, the only thing I can know is that my mind exists.",
"No, maybe when you're older. ",
"TIL Solipsism is a friggin ridiculous theory. ",
"Solipsism is when....\n\nYou say to yourself: \"I think, therefore I am\" KA-BLAAM, you know you exist.\n\nSomeone else says \"I think, therefore I am\" KA-BLAAM, they know they exist.\n\nBut you say to yourself, \"So now I know I exist, but I can't know that other people exist, because I'm not them, and I can't speak for them, only myself\"\n\n\nSomeone else says, \"So now I know I exist, but I can't know that other people exist, because I'm not them, and I can't speak for them, only myself\"\n\nSo, in this world, everyone goes around knowing they themselves exist, but not knowing that other people exist.\n",
"Solipsism is the idea that you cannot prove that anything outside of the mind exists but you can however assume that your mind exists because if it didn't you would not be thinking about it in the first place. \n\nA problem with this however is that solipsism does not go all the way to it's logical conclusion which is that you can only be certain that your thoughts exist. \nSince you are not experiencing the process of the mind that generates your thoughts you just experience the thoughts themselves after they have been thought up you can not say for certain that even your mind exists as the possibility of your thoughts being externally generated is always present.\n\nDescarte should have said not \"I think therefore I am\" but \"There are thoughts\"."
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49orcd | why do investors value higher margins over higher overall profits? | I'm always reading about companies jettisoning lines of business with lower margins, even if those lines are profitable. What's up with that? Wouldn't you rather have 6% of $200 than 10% of $100? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/49orcd/eli5_why_do_investors_value_higher_margins_over/ | {
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"Its more about efficiently using your investment money.\n\nLet's say that the return on the S & P 500 index is 5% a year. I can put money in an index fund and get that return. Instead, I invest in ABC corp, who makes a 7% return - better for me. Now, as I look at ABC corp's books, I see they have a division that is only making 3% return. This upsets me, because if they sold that division and let me invest the money in the market, I could get 2% more return on that money or if they invested it in their core, 7% return business, I could get 4% more return on my money.\n\nIt's not that low returns are bad; it's that investors want money put in areas where it can get the highest return.\n",
"It's about competitive advantage. To get high margins, you have to have a competitive advantage, otherwise competitors scoop in and pricing and margins decline. The higher your margins, the stronger the competitive advantage. It could be anything (brands, skill of management, IP, barriers to entry, innovative products, R & D, etc.). The stronger your competitive advantage, the higher the likelihood that you could invest in the business to grow it and sustain that advantage. Low margin businesses are usually brutally competitive or commoditized (that's why the margins are low) and it makes it difficult to reinvest to make the business grow. The kick you get from reinvestment from low margin businesses is much lower than in high margin businesses. So investors value margins and will pay more for it because it means there is a competitive advantage that provide a better risk/reward for sustained profitability or growth. "
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3m98j3 | why are card games and slot machines at casinos considered gambling and have an age limit, yet arcade coin machines aimed at children are not? | Some of these arcade machines are based mostly on luck and you are technically gambling money in the hopes to win more money. For example, machines such as on those where you drop a coin in at the top, all the coins are hanging over the edge and there's a slider that moves back and forth. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/3m98j3/eli5_why_are_card_games_and_slot_machines_at/ | {
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"Usually those are technically, and by that I mean legally, \"games of skill\" since when/where you drop the coin effects the output. Slot machines are random and do not care if you pull the level or push the button, drop in one coin at a time or hit \"Play Max\", etc."
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1h85h4 | how does the voyager keep leaving the solar system? | It's been leaving for the past year every month... | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1h85h4/eli5_how_does_the_voyager_keep_leaving_the_solar/ | {
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"There's more than one definition of the edge of the solar system. There isn't a simple line in the sand (or in space) that separates our solar system from the rest of the universe. There's a fuzzy boundary, and it takes time to cross that boundary.",
"Because nothing of ours has ever done so before, and every time Voyager reaches what scientists thought would be the \"edge\", they discover Voyager's sending back data they don't expect, which indicates that the sun's influence stretches further than they previously believed. So they refine their theoretical models and wait to see what surprises it comes up with next."
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5qlz5w | how are bots able to get around captchas and security features on ticketmaster to buy thousands of tickets to concerts at a time? | _URL_0_
"In 2013, the ticket retailer Ticketmaster estimated that bots sometimes purchase more than 60 percent of the tickets for a given show" | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5qlz5w/eli5_how_are_bots_able_to_get_around_captchas_and/ | {
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"Just to be very clear-- we have no idea how many (if any) tickets are purchased by bots on ticketmaster. In fact the article embedded in this states so, as below\n\n > Live Nation will not say how many of the 148 million tickets it sells each year are bought using bots, and in many cases it may not know\n\nBut basically, in the case where there is bot-like activity, its just cat and mouse. Someone designs a bot to specifically defeat their one single method, and then runs it and over and over, refining it till its right.\n\nHowever--- another, somewhat more complicated, but ultimately still \"Easy\" method has long been used to buy mass amounts of tickets, and its totally and fully legal. That is, pay people to do it. You can get people in places like India or SE Asia for pennies, by the thousands, to log on exactly as tickets go on sale, buy up everything, and put those tickets in your hands. No bots, no issues, those are actual people. The cost to you? tiny, the legality? fine, and now you have tons of tickets!"
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b9t0m5 | how are oranges specifically grown to be "easy peelers". or is it just simply a variety of orange. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/b9t0m5/eli5_how_are_oranges_specifically_grown_to_be/ | {
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"Selective breeding. People plant the seeds of the ones that are easy to peel and don't plant the seeds of the ones that aren't. You can do this to get almost any quality if you give it enough time.",
"Juice oranges are not an easy peal variety but naval oranges are. It's just a term referring to the variety. If it's meant as an eating orange or a juice orange."
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d42j2s | kids medicine is dosed by weight but all adult medication is essentially take 2 pills. | As a regular sized adult male surely I need more medicine than a small female? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/d42j2s/eli5_kids_medicine_is_dosed_by_weight_but_all/ | {
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"That's not even remotely close to true, though. You've just happened to have been given drugs at a dosage that requires you to \"take two however often\".\n\nA lot of common antibiotics for example have a wide safe dosage range.\n\nAdditionally, children are still developing and are more sensitive to a lot of things.",
"I’ve found the difference to be “If you’re at home and need a couple of painkillers, two is safe” versus “if you’re in hospital and need help, we’ll do the math and you’ll get the highest safe dose”",
"Not sure the answer but just wanted to put this out there: kid’s medication is usually more concentrated to allow an easier time in getting kids to take the medicine. Some people think it may be weaker and give a child more but that could be dangerous."
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2d4m0e | does listening to things in your sleep actually work? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2d4m0e/eli5does_listening_to_things_in_your_sleep/ | {
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"text": [
"Sadly, many studies have [discredited any claim](_URL_1_) that we learn facts and information while asleep. Although, we are apparently capable of [being conditioned](_URL_0_) while asleep. ",
"The only way most things are encoded into our long term memory is through deliberate attention, and usually through deliberate, attentive practice. Think of your mind as an overgrown garden, with new information being wild plants just outside the bounds. You have to notice the plant, hack a path to it, and prune things away from it. Only then will you be able to find it later (and harvest seeds!)",
"Think about it this way: when students are asleep in a lecture, do they actually absorb the information their prof/teacher is telling them? \n\nThe answer is no btw for those who are thinking about it. "
]
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"http://www.npr.org/blogs/health/2012/08/28/160137395/can-you-learn-while-you-re-asleep",
"http://yadda.icm.edu.pl/yadda/element/bwmeta1.element.elsevier-3044fc6c-d7fe-3dd0-85d6-a1e4e90a251f/c/main.pdf"
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||
2t8nct | the creation of aquarium glass. zoo's have huge pieces of glass containing the tank. how is this glass created and installed? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2t8nct/eli5_the_creation_of_aquarium_glass_zoos_have/ | {
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"It isn't glass. It is plexiglass, which is stronger despite being less dense (heavy) as well as much easier to manipulate/form. Still, it can be as thick as half a meter or more (~1.5feet) in a large public aquarium.\n\nMore info:\n > Polymethylmethacrylate (PMMA) is used. This is also known simply as acrylic or by its various trade names, such as Plexiglass and Lucite. PMMA is half the density of glass and has twice the tensile strength. It also flexes and has a lower refractive index. This allows the aquarium window to be thinner and give a clearer view. \n > _URL_1_\n\nAlso of interest, albeit more general about aquariums: \n > The original Berlin Aquarium, for example, which was built **in 1867** and lured 100,000 visitors in its first three months, had to import a gorilla, sell salt water and rent out tank space for the local restaurants' lobsters and trout. Technology was not quite ready to maintain its 50 tanks enclosed in stone-lined grottos; **glass panels burst**, rats set up shop and salt water corroded pipes and pumps. \n > _URL_0_"
]
} | [] | [] | [
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"http://www.nytimes.com/2006/03/23/arts/23aqua.html?pagewanted=all",
"http://www.sciencefocus.com/qa/how-thick-aquarium-glass"
]
] |
||
2qjxah | why do 30 second medication commercials spend 20+ seconds explaining worst case scenario risks and warnings? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2qjxah/eli5why_do_30_second_medication_commercials_spend/ | {
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"At least in the US, there's a law which says that if an ad for a drug tells you what that drug does, they have to tell you about possible major side effects in the same ad. A lot of drugs have lots of potentially major side effects, so there's a lot to tell you about!",
"The FDA heavily regulates Direct-to-Consumer Pharmaceutical Ads (DTCPA) that fall within three categories:\n1) \"Help-seeking\" ads in which a condition and/or symptoms are briefly mentioned, discussed, portrayed by actors, etc..they don't state what the medication is and are intended to inform those who may identify with some of the symptoms there is treatment available and are encouraged to seek the help of a physician for more information.\n2) \"Reminder ads\" are exactly that and intended to remind patients of their condition and to encourage them to take/continue to take medication as prescribed by their physician. These commercials are allowed to mention the name of the medication, dosage, price, and that's about it. The important common thread for these first two that separates them from the type of commercial you're asking about is that they don't make any claims so the rules are less strict.\n\nThe third and final type of DTCPA is a product CLAIM ad that says outright that their medication < insert name here > is effective in the treatment of < insert affliction here > and that it is safe..well, safe enough for the benefits to outweigh the risks. This is where the FDA is by far the most strict in mandating that all major drug interactions, potential side-effects, and disqualifying or even life-threatening conditions or even the aforementioned items are clearly stated.\n\nYou can find a good article on the subject by C. Lee Ventola of the National Institute of Health (NIH) here: _URL_0_\n\nas well as a table summarizing the types of ads and the FDA's requirements for each here: _URL_0_table/t1-ptj3610669/\n\n*Note: this has always been a hot topic of debate and you will often find commercials violating the regulations set forth by the FDA, as a result I didn't include any links to example commercials because I couldn't find any that don't break one or two rules."
]
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[],
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"http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3278148/table/t1-ptj3610669/"
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||
46xuud | why treadmills are bad for your knees? or if this is a myth? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/46xuud/eli5_why_treadmills_are_bad_for_your_knees_or_if/ | {
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"Running is bad for your knees. The biomechanics of running on a treadmill are slightly different than running on the ground, but none of this is harder on your knees than running generally. In some cases, running on a treadmill is _better_ because it has a cushiony landing for you, reducing the impact to your joint.\n\nedit: spallimg",
"The last couple decades of jogging philosophy have been dominated by the idea of big cushion heel shoes so that you can land with your foot out front, toes up, heel down.\n\nIn reality, this causes the impact force to be absorbed by your ankle, knee, and hip joints (inelastic collision) instead of the energy being absorbed in your calf and thigh muscles (elastic collision) by landing on your toes. \n\nThat's not to say that there is no impact from running when you land on your toes. It is certainly there. However, humans are the best runners other planet. Our entire philology is a result of constant improvements to how we run.\n\nThere are other way to burn energy without the increased impact, like cycling, but we're *really good* at running, and even into your 40s your body should be able to adapt to it should you choose to start jogging.",
"I wouldn't say treadmills in particular are bad for your knees. Reason why: They're not because they're usually padded enough to help dissipate some of your landing force--a shock absorber if you will. From my experience, knee pain has more to do with your activity, daily life, posture, *how* you walk/run, how much you weigh, and genetics of course (there are many more situations of course--those are just to name a few). \n\nI'll leave it at that. (I do low key want to put in my two cents about walking/running on concrete vs trails, vs etc, but that was not the question being asked).",
"There have been alot of myths surrounding running. Anything from running on your toes will ruin your shins or that running barefoot will ruin your feet. Everything is circumstantial. In our natural state we run barefoot on softer ground. In our modern state we pound hard surfaces with cushioned shoes much harder than we would without them. It makes running on hard surfaces easier but driving the heel into the ground is not our natural state of movement. The shoes are the real problem. Take them off and you will run differently. "
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1u4fdf | why does gum take so much longer to digest than other foods and where is it during that time? | Why does it take so much longer than other foods such as caramel or taffy? Could I die from swallowing to much gum? Is it coating the walls of my stomach or small intestine? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1u4fdf/eli5why_does_gum_take_so_much_longer_to_digest/ | {
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"While it's true that your body can't digest gum, the idea that it stays in your body a super long time (7 years, or whatever) is a myth. Same as if you swallowed a quarter, barring any complications, you'll pass it out of your system in a day or so, by the usual method.\n\nAs to *why* you can't digest it, the simple answer is it's not food. Your body is made to break down food into usable components - that's what 'digestion' is."
]
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|
dokyv7 | why does it hurt to foam roll muscles? | And further, what is actually happening to the muscle that’s being rolled? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/dokyv7/eli5_why_does_it_hurt_to_foam_roll_muscles/ | {
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"text": [
"You’re literally pulling on the muscle fibers in a concentrated area. The tighter the muscle, the more resistance. The more resistance the more it hurts as it gives."
]
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|
3dnafg | why anyone would be opposed to the iran nuclear deal? | I have been watching the news and I have yet to see/hear one person provide a legitimate reason as to why they believe the nuclear deal with Iran is not a good deal. Every "reason" to oppose the deal I've heard has been some variation of, "This deal is a fast-track to Iran getting a nuclear weapon." Given my (possibly flawed) understanding of the deal, that argument doesn't seem to hold water. Are there legitimate (non-partisan) reasons that this deal is as "terrible" as many Republicans are saying? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/3dnafg/eli5_why_anyone_would_be_opposed_to_the_iran/ | {
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"It gives Iran back their money and opens revenue opportunities for them to sell oil and make even more money. Money they will likely use to expand all their weapons programs, thus threatening their neighbors. Threatened neighbors feel they have no choice but to use a first-strike strategy, leading to a war in the Middle East = bad.",
"There are many legitimate reasons to believe this deal is not the best one we could have gotten (first and foremost we could have gotten a better deal in 2003). This deal doesn't cover Iran's other activities that we dislike, the inspection protocols fall short of \"anytime, anywhere\", and snapback of sanctions would likely not be a fast process and may not be a credible deterrent to name a few.\n\nHowever, the big thing that most opponents haven't really touched is the fact that the alternative to a deal is a costly war.",
"Try posting in r/CMV if you want to hear an actual argument. I am not nearly qualified to really make an informed argument one way or another so I won't. Seems like this thread ended up CJ'ing a little bit.\n\nEdit r/changemyview not r/CMV",
"So what if you gave a drug dealer a 24 day notice that you are going to raid their house, do you think that is smart? Do you think the drug dealer will just sit there and wait and not move/dispose of the drugs or just wait the 24 days out just their so honest",
"First and foremost, there's a solid overlap between \"people who are skittish about Iran having the capability to create a nuclear weapon\", and \"people who believe that Israel has a right to exist as a sovereign nation\". Those who have a strong belief that Israel should *not* be turned into a crater with a glass surface are a bit more adamant about how threatening Iran is.\n\nThat being said, the next question is with respect to what Iran intends to do. Iran is saying, \"just power generation, really...and some scientific research, we promise\". They've also got the world watching them, and in the same way that you know not to smoke weed during a job interview, Iran knows that saying \"...because we want to make a nuclear bomb and blow away people we don't like\" is a guaranteed way to make a complete mess. So, many are shaky about whether Iran is being truly forthcoming with their motivations behind their requests.\n\nThere are four major reasons why Iran isn't seen as terribly trustworthy. First, Iran isn't a terribly stable government. They had a pretty well documented revolution a few years back, and the leadership is frequently described at being a poor representation of the average Iranian. An unstable government that's barely keeping a revolution at bay does not seem to be the best market for uranium. \n\nSecond, the Iranian leaders have publicly made statements saying \"death to Israel\". Some argue that what they were really saying was something closer to \"we strongly desire that Israel no longer be recognized as a sovereign entity and that Palestine be reinstated\" (citing context, culture, and translation shortcomings), while others take the statements more literally and believe that the Iranian government really would carpet bomb Israel off the map if they had a chance. \n\nThird, there are some reports of Iran supporting Hamas and other terrorist groups. Even if Iran never actually weaponizes their uranium, Iran being able to sell its oil means more money coming in, which is feared will find its way to funding terrorists. \n\nFinally, let's assume that Iran is 100% on the up-and-up, is not funding terrorists, and will never actually make a nuke...and we believe them. Now, we've introduced nuclear material into Iran. Next year, Saudi Arabia wants in, saying \"but Iran has it...\" Next year, Libya is up. Kuwait wants theirs as well, and newly formed Iraq would prefer a nuclear reactor than a few hundred square miles of solar panels in the desert. Now, a big group of people who don't like each other all have a couple hundred pounds of weapons grade uranium in a box somewhere. Add an erector set and a box of fireworks and the phrase \"that escalated quickly\" becomes a question of \"how many mushrooms...\"\n\ntl;dr - The Iranian deal isn't atrocious in itself, but given Iran's track record and next door neighbors, many have concerns that Iran would, either directly or indirectly, further destabilize an already precarious region of the world."
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1ikrbl | why do congressional districts not follow county lines? | Congressional districts seem random to me. What's the deal? Wouldn't it be simpler/less prone to controversy if they simply followed county lines? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1ikrbl/eli5_why_do_congressional_districts_not_follow/ | {
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"Congressional districts are created according to population size while county lines are created for various reasons (geography, politics, etc.) which have nothing to do with population and do not change according to population. \n\nEach congressional district must have about the same amount of population so they have to get creative to get it right. Sometimes they get too creative and put people together in order to help elect certain people (put all the black voters in the same district for example) get elected."
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2e4w2f | how do cars not overheat when they cook outside in california/miami/texas heat for hours? | Not only that, but then you get in (where the interior is like an oven) and turn the car on, heating up the engine and components, etc. How does the car still function normally without overheating? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2e4w2f/eli5how_do_cars_not_overheat_when_they_cook/ | {
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"Running temp for an engine is usually around 195 degrees. Even the hottest of summer days does not approach that.",
"The engine is a metal box fueled by explosions, its normal operating temperature is significantly higher than the ambient temperature, even if it is quite hot outside.\n\nThat means that the engine can still dump heat to the environment, although this becomes less efficient as the outside temperature increases.\n\nHowever, cars are significantly more likely to boil off their coolant and overheat in hot weather, especially if they're stuck in slow moving traffic.",
"Overheating for a car engine is much hotter than temperatures that are uncomfortable for human beings. ",
"Your engine has an operating temperature at which it works optimally, usually around 200 degrees F. This is the reason that you need to warm it up in the winter - it will work, but not well, until it gets to its running temp.\n\nWhen the car is out in the summer heat, it is still below running temperature, even though it is uncomfortable for you. Once it gets up and running, it will cycle coolant through the engine to get rid of excess heat, but only once the thermostat detects that it has exceeded the optimal running temperature.\n\nTL;DR: The operating temperature is way hotter than the summer weather."
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4gxlxn | what would happen to the internet/world if google suddenly went bankrupt and shut down? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4gxlxn/eli5_what_would_happen_to_the_internetworld_if/ | {
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"We would start using Bing or whatever other services filled the void. There will be plenty of companies offering identical services to google. It probably won't be as good to start, and it won't be as integrated as google was, but it will develop pretty fast. There is an absurd amount of money to make from the services google offers and companies will be fighting to the death to take over those spaces.",
"If you mean sudden as in you wake up tomorrow and Google is just gone, it would seriously hurt the economy for quite a while. Search would be the least of anyone's worries. You can move to Bing for that. But a lot of people rely on Google for other services, the most important being email. And even worse than individuals losing their services is businesses losing their services. Many, many businesses depend on Google's huge set of services for their daily operations. From something as simple as email run by Google Apps to entire databases and applications run using Google services and servers. Amazon disappearing would be even worse.\n\nIf you mean suddenly as in unexpected, but still slow enough to plan for, there wouldn't be much of a noticeable difference for most people. Individuals would use another email service, and businesses would migrate to some other company's services."
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21beu5 | why are bananas the classic slipping cliché in most cartoons? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/21beu5/eli5why_are_bananas_the_classic_slipping_cliché/ | {
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"Because... they're slippery.",
"The banana peel gag actually grew out of a real problem in mid-19th century America. Prior to the late 19th century, it was quite common for people to throw their trash in or on the street. This was actually quite a crisis for early American cities - some cities attempted to keep the trash controlled with herd of pigs. It wasn't until the turn of the century that the idea of sanitation crews really caught on.\n\nThat happens to be the same era that bananas were first imported into the US in any significant numbers, and they were very popular. A rotting banana peel is actually quite slippery and hazardous if you step on it. The gag originated in vaudeville but it's been so widely used that it's a trope now.\n\nAs it happens, someone discarded a banana peel right outside my car door once and I stepped on it. It is really slippery and I almost fell. ",
"The use of a banana peel as an injurious prop is actually alarmingly realistic and a reference to its ubiquity on the streets of American cities in the early part of the 20th Century. Refrigeration and shipping speed had combined to make bananas the most popular fruit in the country, and in that age before anti-littering laws, people would just eat the fruit and discard the peels wherever they were. As they rotted, the peels would become quite slippery and thus dangerous to tread upon. Banana peels were in fact responsible for a large number of accidents and injuries, including several severely broken legs that eventually had to be amputated, according to period sources. The problem grew so bad that modern urban street sanitation systems were invented mostly to deal with the peel; in New York City, the banana peel actually became something of a symbol of modern sanitation. This is also frequently homage, just about anytime a cartoon character ends up crashing into a trash can, garbage truck, or any other public-sanitation device, he's likely to find himself having at least one banana peel stuck to him.\nIt has been claimed that the trope actually originated in the time before cars with combustion engines and electric trams, when horses powered almost all public transport. And the huge amount of horse manure that piled up in the streets became a serious slipping hazard. When film was invented, this was considered inappropriate to show, so the banana peel became a substitute.\n"
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5m5xh8 | how and why do almonds have a split directly down the middle? | I was eating some today and I didn't know why this was... | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5m5xh8/eli5_how_and_why_do_almonds_have_a_split_directly/ | {
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"Almonds are seeds, almond seeds are dicots, meaning they have 2 cotyledons. \nWhen you split the seed in half you are exposing each cotyledon\nTherefore both sides of the almond are not completely joined ",
"If you split open the almond you see a tiny little nubbin at the bottom of the split. This embryo is the part that is going to grow into the plant. The main almond part is a food store for the plant. \n\nThe split is there to allow the plant to grow and break out of the nut.",
"Botanist here: They're cotyledons, aka \"seed leaves\". As the seed germinates the developing plant uses them for energy and nutrients until they can produce photosynthetic leaves. \n\n[Relevant picture](_URL_0_)"
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2ev0ua | . why is the mustard pack at most fast food restaurants see through in the back when the mayo and the ketchup packets are not see through. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2ev0ua/eli5_why_is_the_mustard_pack_at_most_fast_food/ | {
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"Maybe to see if it's yellow, Dijon, or Brown mustard?",
"[The ketchup packets are foil. The mustard and relish packets are plastic. Foil is not transparent.](_URL_0_)",
"_URL_0_\n\nNo one knows!",
"Guys we need someone who makes these packets to tell us. We need an expert",
"It's probably for the people handing them out and not the customers. If it was white on the back like the ketchup or the mayo you wouldn't be able to tell them apart unless they were all forward facing. ",
"Is this what you wonder about?",
"I asked our head chef this very question some months ago while we were enjoying a blunt. His explanation was that light can damage the flavor of ketchup and mayo just like it can beer. How true this might actually be I'm not sure, but it sounds right.",
"I'm pretty sure it's because mustard can go bad in the packs and you need to be able to see it to tell before you open it. \n\nSource: One time I was in my friend's car and he had a packet of mustard in the cupholder and I asked where he found mustard that color, he looked at it, told me it was bad, then threw it out the window.",
"maybe at the dawn of the packet game there was only ketchup, when mustard hit the scene they needed to show the people so no one with a fear of mustard fucked up?\nim not an expert nor do i fear any condiment except i don't like chicks who mayo up their fries...",
"mayo and ketchup are very easily spoiled by light where as mustard relish onions can take it.",
"The main driver in packaging these days is price. Foil packaging provides the best moisture and oxygen barrier of the various types of sachets/packets out there but is by far the most expensive. If you find something in a foil packet, it is because when tested in a less expensive plastic variant it failed testing one way or another. More than likely, the product oxidized which can cause an unappealing change in color, odor, or flavor.\n\nIn short, ketchup and mayo must have tested too sensitive to oxygen for the required shelf life of the packet otherwise they would be in the same laminated plastic pouches mustard is found in. If companies could package them in plastic they would; it would save them millions annually at the volumes they sell. \n\nSource: I'm a Pharmaceutical Packaging Engineer with a Master's of Packaging",
"Are you sure it's always like that? The only time I've seen that combo of packaging is when the restaurant is using different brands for different condiments together by chance.",
"How the boner soup did this make the front page",
"Because some things are UV and light stable, like mustard. Something's like ketchup will degrade in light, and discolor. \n\nI sell into the industry",
"Some things are light-sensitive. Mustard is not, Mayo is. I'm not sure about ketchup, but it may be as well."
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7btl4s | why are baby animals cool with humans/other species, but adult animals are not? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/7btl4s/eli5_why_are_baby_animals_cool_with_humansother/ | {
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"Most animals have the instinct to rely on larger creatures (usually their parents) to survive. Partially because they are not ready to defend themselves yet.\n\nBaby birds can't fly away, baby cats don't have the strength to attack, etc.\n\nIf you raise the animal from birth, it will think of you as a family member, but anyone else might be seen as an intruder.\n\nWhen they mature into adults, they will still remember you as \"family\", but they might have other instincts that guide them to try and dominate you, which is why that one chimpanzee killed the lady that owned him after many years.",
"I wouldn't say baby animals are cool with people or other animals- they just can't do much. Kittens with closed eyes will spit and hiss as much as their tiny bodies can given a reason.",
"Like I said before animals and humans have some ways the same. Take for example a kid. He has no idea of danger. Later in adulthood a person learns to distinguish bad and good and be more cautious of people, things and so on. A baby animal is still naive and has no knowledge or experience with evil. The first instinct is to get curious and motivated to engage in social friendly activities. Through bad events later the animal learns to be more self aware of the things around. Trauma or unpleasant events can cause this coldness. "
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3d0ven | why don't we ask primates to teach us their language(s)? | We have been teaching apes ASL for a long time. Now that we know they have gesture based languages in the wild, why don't we ask a primate born in the wild who knows ASL to teach us?
Edit: This is the only source I have found so far: _URL_1_
It isn't the original on I read, but in this one they can still only identify a few gestures with direct responses.
2nd Edit: Better article, same study: _URL_2_
3rd Edit:Here is the wikipedia article for a goriila that was taught sign by another gorilla. He aslo describes events from his past involving his mother. _URL_0_
So we know they can learn ASL, they can teach language, and they are intelligent enough to answer complex questions and describe events from the past. Has no one seriously just asked a gorilla about how they talked to their families or what they talked about? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/3d0ven/eli5_why_dont_we_ask_primates_to_teach_us_their/ | {
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"Do you have a source for this gesture language? I've heard if them knowing sign language that we've taught them but have never heard of them having their own",
"For all they talk once they are taught ASL, no ape has ever told us anything about apes. Not even about their families, let alone their culture or the ape way of life. All their communication is always one-on-one, always about the speaker and the specific person they're talking to. They clearly understand collectives because they live in groups and recognize outsiders, but they don't talk about it.",
" > We have been teaching apes ASL for a long time. \n\nNot really, no.\n\nThe science on this issue is very, *very* weak, and the mainstream consensus is that it may not be much more than the well known \"Clever Hans effect\" at work. It certainly isn't ruled out entirely, but it is an extraordinary claim, and we have yet to see any extraordinary evidence.\n\nThere have only been a small number of cases where some researcher or other has claimed they have taught an ape sign language, and all the cases tend to demonstrate certain scientific Red Flags:\n\n--Small sample size. Only a very tiny number of apes have even been presented as learning sign language.\n\n--Little or no replication of results. Even researchers who enthusiastically claim the effect is real have only been able to teach one or two subjects.\n\n--Selective and subjective data interpretation. One of the things you typically don't see in the ignorant, credulous TV news segments on signing apes is that an awful lot of the \"signing\" they do is nothing but gibberish, and the \"good\" parts are cherry-picked out. And frequently, an ape will sign something like \"purple glbnuxt cookie bucket,\" and the researcher will oh-so-helpfully inform you, \"oh, that's just how he says I want to watch TV.\" Yeah? Sez WHO?\n\nNon-ape intelligence cases such as Alex the Wonder Parrot suffer from similar scientific weaknesses.\n\n"
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"https://en.wikipedia.org/wiki/Michael_(gorilla)",
"http://io9.com/5926132/chimpanzee-hand-gestures-suggest-human-communication-is-even-older-than-we-thought",
"http://news.bbc.co.uk/earth/hi/earth_news/newsid_9475000/9475408.stm"
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1k409h | what happens when you turn your automatic car off when it is still in drive? is it bad for the engine? | Sometimes I get home, and remember to put up all the windows and turn off the lights, but forget to put the car in park before turning it off. It normally makes an unpleasant sound. Is that bad for the car? What's happening to the car that makes that sound? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1k409h/what_happens_when_you_turn_your_automatic_car_off/ | {
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"Not bad for it at all. If your car makes a sound it might be your car alone, try to record it and post it here, or /r/MechanicAdvice. \n\nIf your on a hill and turn your car off without putting in Park, it will start to roll. The Park position on an automatic engages a small lock in the transmission to keep the car from rolling. \n\nYour car also won't start when in Drive or Reverse, because of a safety feature. It should only start when in Park or Neutral.\n\nYou can turn off your car at speed, but it is not recommended. You will loose power steering, making your car very hard to steer. You will also loose the brake booster. There might be enough pressure in the booster for 2 or 3 brakes, but after that it will become extremely hard to brake. Starting your car again will fix both."
]
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66ufcm | how come when phone screens break, they are still completely functional and readable, but when computer monitors or tvs break, they can no longer display the correct colors? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/66ufcm/eli5_how_come_when_phone_screens_break_they_are/ | {
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"When phone screens 'break' they are not actually breaking. It's just the glass coating over the screen. They have that coating to protect the phone since it probably gets handled and dropped more than a TV.",
"You are breaking the digitizer on top the panel. If the crack goes deep enough to crack the actual display panel, it'll look like a broken monitor. The digitizer is what reads the touch input hence isn't on tv's and most monitors.",
"To explain it simply...when you break a monitor, you're breaking the screen directly.\n\nWhen you're breaking a phone screen for the most part, it's like breaking a glass panel placed over the monitor rather than the monitor itself. The glass is there for structural rigidity and to protect the LCD as LCDs are very, *very* fragile and break easily. So the glass takes the hit rather than the LCD, and breaks.\n\nBonus trivia: Usually the digitizer (the thing that tells the phone that you're touching in a certain area) is laid over the LCD (and under the glass) and thus that's why even if a phone is cracked the touch screen still works fine. If you actually pulled off the glass entirely touch would still work okay but the display itself is as fragile an eggshell so the glass is there for structural support.\n\nNotable exceptions to this are some LG phones that seem to have the digitizers integrated into the *glass*, so when they break, touch no longer works."
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85oebp | on wwii propeller planes, how did the nose guns shoot without damaging the blades? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/85oebp/eli5_on_wwii_propeller_planes_how_did_the_nose/ | {
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"With a [interrupter gear](_URL_0_). The technology was developed in WW1. It's a simple mechanism that blocks the gun from firing when the propeller blade is directly in front of gun.",
"If the gun was shooting through the same space as the propeller, there was a timing mechanism incorporated between the gun and the propeller so that it only fired during the space between the blades. A much cheaper alternative was to mount the gun above or below the propeller.",
"This was more of an unknown in WW1, actually. The guns were synchronized with the propellers, which aren't in some random location, but in a very predictable position based on position of some shafts.\n\nHere's a picture of how it works. _URL_1_\n\nFrom this article. \n\n_URL_0_",
"The answers given below are correct. Interrupter gears were used, and if they ever failed it wasn't a big deal, the pilot could glide to a safe landing (hopefully behind their own lines). Some alternative designs had the pilot or bombardier able to stand up in their seat and fire a gun mounted to the top wing, over the propellor arc, also useful as it could slide back and fire directly upwards, so one could fly underneath an enemy and shoot upwards into the plane above.",
"Though it was limited to WW1, it's too funny not to mention: earlier solutions to this problem involved reinforcing the propellers with steel deflectors to ricochet bullets in (hopefully) harmless directions, then just shooting, in the hope that most bullets would make it through. This saw success, even though bystanders were killed by ricochets at the first demonstration of this technology.\n\nEarlier even than that, pilots would snipe at each other with handguns and rifles. I've even read of a brick being thrown.\n\nEarlier even than that, to even fly was so novel that there was a collegial atmosphere in the air. Planes were used for reconnaissance, and pilots would exchange friendly waves.\n\nEarlier even than that, we hadn't invented planes.",
"The slomo guys actually did an episode on this very thing. Was an interesting episode. \n\nI'm too lazy to post the link so...Google it or something. ",
"when you hold the trigger the gun doesnt fire until a little dingaling on the rotor blade shaft (inbetween two rotors in the empty space) hits a whatchamacallit, but since the blade spins so fast your dont really notice a delay. therefore if the gun is mounted on top of the aircraft at 12:00 it only fires when the rotors are at 9:00 and 3:00. \n\nThats as eli5 as it gets. ",
"There are two ways to do it:\n\n* Interrupting syncronization. Stops the gun from firing when it would hit a propeller blade.\n\n* Synchronization. The gun is controlled by the engine shaft, so it fires at the same rate (or a ratio of it) as the propeller spins."
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1it560 | what is a police state? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1it560/eli5_what_is_a_police_state/ | {
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"A police state is where the government exerts harsh, rigid, totalitarian-like control over both social life and the economy. While it's impossible to define just when a nation becomes a \"police state\", there are a few traits we can note:\n\n* Possible apartheid tendencies, where social divisions are forced upon society\n\n* Excessive surveillance of the population, all-encompassing intelligence agencies, and an attempt to actively monitor the population\n\n* Controlling and restricting free press\n\n* The use of secret police or clandestine raids on people who oppose the government. Dissident or opposing views might be restricted or outright forbidden\n\n* Police brutality, near infinite police power (such as not requiring warrants), and the police being used to enforce more draconian and authoritarian laws\n\n* Sometimes the military might stand in for the police, or there might be little distinction between the two",
"Okay, Think of [Nolan Square](_URL_0_). If we separate freedoms into two categories: personal freedoms (gay rights, abortion rights, freedom of religion, etc) and economic freedoms (low taxes, less gov. regulations etc.) we can measure where a country or a person is politically. If a person likes personal freedoms but not economic they are liberal, if a person likes economic but not personal they are conservative, if a person likes both they are libertarian and if a person likes neither they are totalitarian. A police state is basically a form of a totalitarian state. "
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3qhi2c | maybe i'm just young, but why was pulp fiction considered such a great movie? | It seemed like a scattered plot with not much of a story. Was it something to do with when it was released? I understand the actors that were in it are big time but is that enough to make a movie a top 10 all time film?
Sorry if this offends anyone. Please excuse my ignorance. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/3qhi2c/eli5_maybe_im_just_young_but_why_was_pulp_fiction/ | {
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"You have to keep in mind, this movie was EXTREMELY influential for its time. while I still think its an amazing movie in its own right, you should always take the time period into context. It has some of the best written and believable dialogue of any movie i've ever seen, while also not following any traditional movie structures (which you saw as \"scattered plot with not much of a story\"). It also had an extremely interesting blend of comedy and violence, which movies still struggle to do well. I could keep going for awhile (hell, i could write an essay on this movie), but feel free to ask any other questions if you have them",
"So, first I should say that the actors in the movie weren't particular big time when they were in it. Most were either up and coming, worked with Tarantino previously, or washups. \n\nSecond, you have to ask yourself what makes a good/great movie. I like to think that there are two major aspects to a great film the narrative and the technical or \"filmic\" attributes. Narrative also has two components the plot itself and the technical aspects of the narrative itself. Pulp fiction is a very \"post-modern\" movie. Almost every single scene in terms of the way the framing is set is meant to be an homage to another movie. The writing itself is also extremely referential which is considered cool within the context of \"post-modern\" art. Lastly, while its true the plot is very scattered I would strongly disagree about the story. It's meant to portray a picture about violence on the fringes of society bleeding into mainstream society (partially because of things like movies, hence the endless referentiality), which I think it does amazingly well. \n\nI'm gonna avoid getting too into the discussion of \"post-modern\" art tics (so I'll just leave that up to the context component). But, because this type of art is very much about film movie buffs tend to love it especially. That's why it often ends up on top 10 lists (because people who are movie buffs tend to be the sorts of people who make top 10 lists). That isn't to disparage the movie, I think it's amazing for all of the reasons listed, but that's precisely because of the above context. ",
"It's not a case of it being a deal because of big time actors. They mostly weren't top stars at the time - Willis had had a couple of Turkeys, Jackson had an ok career but wasn't really a headliner, Travolta's career was nowhere.\n\nIt was more about the Tarantino tbh, script and direction. I'm not really a QT or film expert but basically he's a massive film nerd and draws inspiration from all sorts of relative obscure sources: b-movies, old movies, foreign movies etc. He's kind of postmodern; without getting too much into the entrails of postmodernist debate, by this I mean his films kind of know they are films, the audience knows it, and QT knows the audience knows. Pop cultural references, toying with the fourth wall, non-linear narrative, self-referential / meta- stuff. etc.\n\nThese days this 'knowing', referential style is absolutely everywhere, even in the mainstream, and stuff kids grow up on, like the Simpsons etc. Age of youtube, everything is immediately remixed and peppered with references to other things but back then, not so much. Now I should not give the idea that this sort of thing was novel, per se. Obviously there are loads of tricksy non-linear films and oh so clever postmodernist works of art cinema, well before Tarantino, but consider most Hollywood output in 1994, action/crime output in particular. The early 90s were really very 80s, in hindsight, so 80s action movie tropes and formulas are still largely dominant. i.e. Films that take themselves very seriously, expect little from their audience, very standardised patterns of manly heros having a training montage before killing the bad guy with a corny quip... Getting very predictable and spoonfed...\n\nPulp Fiction comes along and has the non-linear, 'make the audience piece it together' trickery of the most arty arthouse film, in comparison, and the dialogue is similarly on a whole different level of intelligence. Plus all QT's film nerd stuff: if you were a film nerd who'd watched obscure 70s hong kong b movies too it was fun to spot the things he was lifting, and for most of us who weren't and hadn't, it all just felt new and fresh. \n\nCombine that 'intellectual' side with enough familiar elements of action movies ('badass' characters going around shooting people, looking cool and saying quotable things) that it's still very accessible, not too arty and weird, plus decent cast, decent performances, zeitgeist-striking musical embellishments, it was a kinda 'perfect storm' I suppose. I don't know enough about film to say if it really deserves to be in an all time top 10, but that's why it ended up in so many people's personal favourites.\n\nJust my 2p",
"Others already addressed the technical aspects of it. I'd like to add another perspective: it's not actually that well received among critics and for lack of a better term \"cinephiles\" (think r/truefilm or the clientele of your local arthouse cinema) as well as the wider/general public (think Avengers/Hunger Games cinema goers).\nBy both of these groups it is likely regarded as a well-made, entertaining film for sure, but in the case of the first demographic you won't find it in many of their Top 20 lists (including top critics), and the latter it might have not left a \"special\" enough impression (in regards to other action or gangster films), perhaps even left a bad taste, as many of the nuances of Pulp Fiction are pretty unique compared to Hollywood cinema.\n\nThe reason I say this isn't because I try to sound condescending, but because OP called it \"considered such a great movie\", which opens a whole can of worms–to whom? I think it has that position at the top only in the classic Imdb/Reddit mid brow camp. "
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4pm5lb | what does david cameron's resignation as prime minister mean for britian and the rest of the world? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4pm5lb/eli5_what_does_david_camerons_resignation_as/ | {
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"Basically, nothing. David Cameron steps down as prime minister someone from the Tory party will be voted to be their leader/representative and become the new prime minister. That's it really.",
"Cameron didn't want the Brexit so he doesn't want to be involved with the actual process of leaving the EU, which makes sense. Someone who is for it can negotiate in good faith with Europe for a clean exit. ",
"What does Britain stand to gain by leaving the EU? What would cause a majority of people to decide it would be best to leave?"
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mh5pa | can anyone eli5 the moment generating function? | We talked about it in my probability class today. I'm fine with pushing symbols around but it'd be good to have a simple explanation of what it means and why it's important. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/mh5pa/can_anyone_eli5_the_moment_generating_function/ | {
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"It's hard to ELI5 since no five year old will know anything about basic probability theory or function transforms.\n\nPerhaps I'll first just explain the name. The nth moment of a random variable is the value E[X^n]. Each moment tells us a little more about that variable's distribution. The mean E[X] tells us the mean, the variance (not exactly the 2nd moment, but almost) tells us how spread out it is and so on. The moment generating function is nice because it \"contains\" all the moments. E[e^{tX}] will be a function of t. When you take the nth derivative at t = 0, you get nth moment of X. So that's kind of nice.\n\nBut really, it's useful for the same reason lots of function transforms are useful. If you're taking probability theory, you've probably also taken courses that have taught you the Laplace transform or Fourier transform. Take the Laplace transform. Why is it useful? Well if we work in the \"transformed\" domain, sometimes it's easier to do things like solve differential equations. The Moment Generating Function is similar (in fact, it is actually very related to the Laplace transform). It lets us talk about the distribution of a random variable in a different way which might let us perform things more easily.",
"It's hard to ELI5 since no five year old will know anything about basic probability theory or function transforms.\n\nPerhaps I'll first just explain the name. The nth moment of a random variable is the value E[X^n]. Each moment tells us a little more about that variable's distribution. The mean E[X] tells us the mean, the variance (not exactly the 2nd moment, but almost) tells us how spread out it is and so on. The moment generating function is nice because it \"contains\" all the moments. E[e^{tX}] will be a function of t. When you take the nth derivative at t = 0, you get nth moment of X. So that's kind of nice.\n\nBut really, it's useful for the same reason lots of function transforms are useful. If you're taking probability theory, you've probably also taken courses that have taught you the Laplace transform or Fourier transform. Take the Laplace transform. Why is it useful? Well if we work in the \"transformed\" domain, sometimes it's easier to do things like solve differential equations. The Moment Generating Function is similar (in fact, it is actually very related to the Laplace transform). It lets us talk about the distribution of a random variable in a different way which might let us perform things more easily."
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dea6g0 | are are zoo animal births less successful than in their natural habitats? if so... why? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/dea6g0/eli5_are_are_zoo_animal_births_less_successful/ | {
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"Zoo animals births are 1000x more successful than in the wild. Zoos aren't just a place for entertainment. \n\nIt a rehabilitation center focusing on saving species. \n\nIf an animal is born in a zoo there's a WHOLE medical staff ready to jump in if there's any signs of distress or issues. The baby then gets checked their shots and reintroduce to their mother and monitored closely by the staff. To ensure its health\n\nThey don't have that in the wild. Especially predators. Ready to kill the newborn."
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9wry2c | how is the speed of an airplane calculated when it is in the air? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/9wry2c/eli5_how_is_the_speed_of_an_airplane_calculated/ | {
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"A pitot tube located on the outside of the aircraft in the airflow, measures the airflow and indicates the velocity in the airspeed indicator inside the cockpit or a GPS which uses satellites.",
"Airplanes have pitot tubes. This measures the static air pressure to determine speed. Think of how a tire pressure gauge works and you'll get the idea. \n\nThe open end of the pitot tube faces toward the flow of air. The airspeed indicator measures the air pressure differences between the stream of air and air not in the stream of air. When the airplane is standing still, the pressure in each tube is equal and the airspeed indicator shows zero. The rush of air in flight causes a pressure differential between the static tube and the pitot tube. "
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5qrmw7 | why do they say pinching yourself will wake you from a dream? how can someone control the substance of their "lucid dream"? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5qrmw7/eli5_why_do_they_say_pinching_yourself_will_wake/ | {
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"Studied and practiced lucid dreaming for a couple years. To answer your first question, pinching yourself in your dream can cause a pain response. When you dream, the logic center of your brain goes into a resting state, that's why in dreams everything is \"seeing is believing\". When you pinch yourself in a dream and invoke an imaginary pain response, your conscious mind becomes more alert, which can cause your dream to destabilize and you to wake up, however, this might not always be the case. Sometimes you can have a false awakening, which is when you dream about waking up... From a dream. But that gets into another topic! As for your second comment. Having more control over your lucid dreams requires you to BELIEVE you can do the things you want to do in a dream. Want to fly? You have to believe you can or you won't because your brain will consider it illogical. Want to teleport? Believe you can. It will take practice but it will pay off in the long run"
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4z19qq | with an infinite spectrum of frequencies to choose from, why does everything use 2.4ghz? | Microwave ovens, wifi, Bluetooth, and countless proprietary wireless protocols all use 2.4 GHz. What's so attractive about this specific frequency? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4z19qq/eli5_with_an_infinite_spectrum_of_frequencies_to/ | {
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"It is one of a small number of frequencies reserved by regulators for free use without a license.\n\nMany other frequencies are better for communications, but have been reserved for licensed use.",
"We use lots of frequencies for all sorts of things! Here's a map for how frequency is used in the US:\n\n_URL_0_\n\nIf you zoom right in near the end of the 300MHz - 3GHz spectrum you'll see \"amateur\" at around 2400:\n\n_URL_1_\n\nThat's a region of frequency reserved for anyone to use without a license. It happens to have reasonable range and decent bandwidth, so we use it for things like WiFi and home phones.\n\nThere's also another amateur chunk at around 4.7GHz, which I presume is where 5GHz WiFi sits. \n\nThere's another big chunk of amateur at 3.3Ghz. Which I believe the FCC has been doing a laissez-faire licensing scheme for WISPs (wireless ISPs, normally very small and somewhat unprofessional operations with only a few hundred subscribers). \n\nApart from that you'll see big chunks reserved for older technologies (that were quite inefficient), like analogue TV and navigation. Then a whole mish mash of other frequencies, reserved for all types of things.\n\nHave you heard of LightSquared? There business model was basically pretending to be a satellite company, so they could use a chunk of the land-satellite frequency for 4g mobile (which is land to land) networks (which are in high demand). "
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"http://puu.sh/qKSPI.jpg"
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r7imc | how much would it really matter if tomorrow, the moon was gone? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/r7imc/how_much_would_it_really_matter_if_tomorrow_the/ | {
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"* There would be no more tides, possibly causing problems for many high tide ports around the world, but they would adapt.\n* Animals that use the moon for navigation or night vision would be confused.\n* Animals that use the tides as part of their life cycle (for example, giving birth in tide pools) would probably be devastated.\n* Deep sky astronomers would be very happy.\n* Moon observers and researchers would be very sad.\n\nI'm sure there are more things that aren't coming to mind right now.",
"The moon helps keep the earth balanced on its axis. Scientists believe that a .5 degree shift turned a lush forest into what is currently the Sahara desert. Imagine what would happen if nothing was holding the earth on its axis. If a .5 degree can turn forest into desert, imagine what a 90 degree shift might do.\n\nI watched a documentary called \"If We Had No Moon\" that went really into all this. The short answer to your question is a lot. It would matter a whole frickin' lot.",
"There might be some larger effect on the Earth without the Moon in the system (the key word being system). Remember -- the Moon does not revolve around the Earth. They each revolve around a common [center of mass](_URL_2_), or barycenter. That barycenter, in turn, orbits around a common barycenter with the Sun. \n\nRemoving the Moon's mass will make the former Earth/Moon system less massive, so the attraction between Sun and Earth will be slightly less, and the Earth will move slightly away from the Sun. I have no idea how far, to be honest. Maybe not enough to make a huge difference -- the Moon is 1/80th the Earth's mass, so the movement might be on the order of hundreds of kilometers, which is meaningless in terms of an astronomical unit...\n\nBut... the Earth's axis might tend to get a bit more wobbly without the Moon, and the length of the day might also change because the Moon isn't there to create tidal forces (different from ocean tides) and put a brake on things. \n\nThere is a [theory](_URL_1_) that life on Earth would not have been possible without the Moon, but that was in the past. \n\nAnyway, for a more like ELI18 version, see [here](_URL_0_)."
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"http://www.newscientist.com/article/dn4786-no-moon-no-life-on-earth-suggests-theory.html",
"http://en.wikipedia.org/wiki/Barycenter"
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1i5lzp | the concept of work in physics? details inside. | Robert M. Hazen "You do Work if you push you're car along the road as long as it is moving,but if the car doesn't move no mater how hard you push or how much sweat you work up you're not doing any Work,in the same manner if you lift a heavy weight you're doing Work but if you just hold it out in front of you ,no mater how tired you're arm gets since you're not exerting a force over a distance you're not doing any Work,that is the formal definition on Work."
Because you keep the weight in front of you from falling don't you apply a force opposite to gravity?Just to keep the weight in place in space?
Edit :Now i understand, thanks to you all the matrix has unfolded.
| explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1i5lzp/eli5the_concept_of_work_in_physics_details_inside/ | {
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" > Because you keep the weight in front of you from falling don't you apply a force opposite to gravity?\n\nYes, but force and work are different concepts.\n\nWork is the change in the potential energy of the object. If you don't lift the object against gravity (in other words, *move* it), you haven't added any energy to it. Therefore you've done no work.\n\nW = Fd. If d is zero, work is zero, even if F is non-zero.",
"The key to this concept is that there is a difference between force and work. Force describes a potential, which means that if you apply force to something, but fail to move it, it only has the potential to move (if, for example, obstacles are cleared).\n\nWhen you are grunting and pushing and shoving on something immovable, you aren't performing any *desired* work. Obviously it feels like you're working, and in reality you really are working - pumping blood, burning calories, changing muscles. But no work was performed on the object you're trying to move, because you have not given it any potential... such as inertia or elevation.\n\nWhen you're holding something up against gravity, the reason it is tiring is because the way in which you are producing an (equal) opposite force is through an efficient function of your muscles. You do work to set up that force (contract a muscle), but then the muscle weakens and you have to burn new calories to maintain that force. You aren't performing work on the thing you're holding up, because it isn't moving; you're just performing work on your muscles.\n\nThere are other body parts, such as your lap, that do not have this disadvantage. You can hold something off the ground more efficiently just by putting it on your lap. Your heart rate doesn't go up, muscles don't have to contract, etc, so you are spending no work on counteracting the force of gravity... and still, you're performing no work on the object you're holding up either.",
"**Mass** is resistance to acceleration. Very massive things resist acceleration more than less massive things.\n\n**Force**, if unopposed by any other forces, will cause a massive object to accelerate when applied to that object. How quickly and in what direction the object accelerates depends upon the mass of the object and the force involved.\n\nI like this way of explaining these concepts because of the three entities in the equation `F=m*a`, acceleration is the only one we can direction observe. We like to think that we can \"feel\" the weight of objects and so we tend to give equal observational weight (hehe) to mass and acceleration...but then we learn the difference between weight and mass and we come to realize that they are not the same and we are feeling weight, not mass. (On Jupiter, the same object would feel heavier, so we're not really feeling mass after all.) In this way, of the three, acceleration is the most conceptually fundamental because it's what we have direct access to experimentally.\n\nThere is no guarantee that when you apply a force to something, you will be able to get the energy you're spending back out of it. Sometimes you can, for instance, if you accelerate something you've given it kinetic energy and you can then harvest that kinetic energy later for some useful purpose. This is kind of easy to understand. You shoot a bullet, the bigger and faster that bullet, the more damage it's going to do. We have an intuitive sense of how energy is conserved when it comes to kinetic energy.\n\nBut what happens when you apply a force to something that doesn't move? Say you push down on a rigid sphere that's on rigid ground. It doesn't move at all. When you're done with all that pushing, you've expended a lot of effort, but what's different with the sphere? Have you increased the system's (in the case, the system is the sphere) harvestable energy in any way? No.\n\n**Work** is a way of tracking the state of energy being transferred to or from a system. If you apply a force to something, but it doesn't move, you may have expended effort but you have not done any work on that system because it has the same total energy it had before. On the other hand, if you raise the sphere up off the ground, now it has the potential to transfer energy to something else when it is dropped. This energy was transferred into that system because when you applied a force, the object was actually moved in the direction of the force being applied. Even though it stopped, it now has more potential energy because of that movement.\n\nIt's worth pointing out that *movement* does not imply work is being done on a system, but *acceleration*. If I shoot a bullet out of a gun, the explosion of the cartridge does work on the bullet by accelerating it, but once it escapes the barrel of the gun there is no more explosive force pushing it, and it travels at a constant velocity (in space, in air the air would do work on it in the other direction through friction). When the bullet hits its target, that target stops it by accelerating it to a stop (decelerating, if you wish). If this is on the surface of Earth, the planet does work on it by accelerating it down and causing it to travel in an arc instead of a straight line. All of these things are movements in the direction of a force being applied, and so we can safely say that energy is being transferred into or out of the bullet (which is our system for this example).\n\nIn the example where we lift the ball up, we need not actually accelerate it because there is an opposing force, gravity, working against us. This matters because it means that gravitational force will let us get the energy out later. It's stored as \"potential\" energy. In empty space, if we apply a force to the sphere there is no opposing force, so the sphere will just keep accelerating if we keep the same force applied to it, but now we're adding energy in the form of kinetic. As long as force is applied *over an actual distance*, we can calculate the amount of energy being added to the system by looking at that force and that distance.\n\n**[update]** language, added more clarification to make a little less confusing (hopefully)"
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9f3nnl | what is the difference between permutations and combinations. | I cannot for the life of me get the difference between permutations and combinations. My teachers have explained multiple times, claiming that permutations tends to refer to order and arrangement, whilst combination usually “choosing from a group of people or committee”. While I do get these, I do not understand why arranging a committee of five boys and three girls for example under no restriction requires the use of permutations. I mean their names aren’t even specified and if theres no restriction should’t that mean that theres no “order”? Ok at this point I just sound stupid and all but really is there no any other way to differentiate when to use both? I’ve been reading math articles on google and watching videos but when it boils down to doing the question I am still as confused as ever. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/9f3nnl/eli5_what_is_the_difference_between_permutations/ | {
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"When discussing permutations, the order of the items selected is counted: two sets of items with the same members, but chosen in a different order, are respected as a distinct permutation.\n\nIe the sets [1 2 3] and [2 1 3] out of a set of the positive integers from 1 to 100 would be distinct permutations, but one combination.",
"You use combinations when the order of the things you are choosing does not matter and you have a limited set of choices. Let's say you are going to choose 3 people to go to the movies from your friends and you have 4 people to choose from. Let's call them A, B, C, and D. Choosing A first, B second and D third is basically the same thing as choosing B first, D second, and A third, since you will go to the movies with the same people in the end. So the number of possibilities you have is:\n\n{A,B,C} {A,B,D} {A,C,D} {B,C,D} = > 4\n\nIn permutation, the order of the things you choose matters and you still have a limited set of choices. For this one, let's say you went to the movies with your three friends A, B, and C and you want to choose how you are going to sit but there are only three seats so one of you will not be able to sit. In this case, you sitting in seat 1, A sitting in seat 2 and B sitting in seat 3 is not the same as A sitting in seat 1, B sitting in seat 2, and you sitting in seat 3 because you end up sitting in different seats because of the order you choose. In this case the possibilities you have is:\n\nX being you\n\n{X,A,B} {X,B,A} {A,X,B} {A,B,X} {B,X,A} {B,A,X}\n\n{X,A,C} {X,C,A} {A,X,C} {A,C,X} {C,X,A} {C,A,X}\n\n{X,B,C} {X,C,B} {B,X,C} {B,C,X} {C,X,B} {C,B,X}\n\n{A,B,C} {A,C,B} {B,A,C} {B,C,A} {C,A,B} {C,B,A} = > 24\n\nFor the same problem(choosing 3 out of 4), combination and permutation gave us different answers since in one of them the order you choose didn't change anything and for the other it did."
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4ciqc6 | what does it mean when drinks are only 20% juice? what is the other 80%? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4ciqc6/eli5_what_does_it_mean_when_drinks_are_only_20/ | {
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"Something else--probably added water. If I have a bucket of juice, straight from the fruit, and add four buckets of water, I've got a beverage that's 20% (1/5th) juice. Some juices taste strongly and are more palatable watered down, and of course this is cheaper as well.",
"Most likely added water and added sugar. \n\nTake a glass. Fill it 1/5 full of orange juice. Fill the rest of the cup with Crush orange soda. You now have a 20% juice orange drink.",
"Ingredients are listed in descending order. In juices, water is most likely listed first as it makes up the most of the drink. Sweetener is usually second. Flavoring. Preservatives. Added Color and so on. ",
"Water. Then they add sugar and coloring to get the taste and appearance back to normal. If you've ever had real cider vs apple juice it's a world of difference. ",
"Fast rule of thumb: Beware products that are called \"drink\" or \"beverage\" rather than \"juice\". Apple Drink, Orange Drink, etc. \n\nProducts like Sunny D, for example, look superficially like orange juice and are usually sold from the same coolers, but it's basically just non-carbonated Orange Crush, with about the same nutritional value."
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9v5l10 | why are horses put down when they get injured racing. why not have them recover and live their lives out. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/9v5l10/eli5_why_are_horses_put_down_when_they_get/ | {
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"Horses are difficult to treat and expensive to keep. A horse with a broken shoulder would be very hard to have recover at all, and even if somehow it survived it would never be able to race again. So why spend huge amounts of money on obtaining an old, lame horse?\n\nI know the desire to keep animals alive but most people don't have a million dollars to throw at such a task.",
"Because you'd have to keep a horse off it's feet to allow the injury to heal\n\nHorses sleep, eat and do everything else standing .\n\nOther than occasionally lying down when rem (rapid eye movement) sleep is needed.\n\nThat should show you how not worth the work that process of trying to heal it would be. Some racehorses are worth tens of millions USD.\n\n\n",
"Horses can't heal very easily. A shoulder injury like that would probably need the horse to not use that leg for the length of the healing process (to prevent it from damaging the shoulder more). Horses can't walk on 3 legs, it puts too much strain on the other 3 and causes a lot of pain for the animal.\n\nThey also can't just lay down. Horses are far too big to do this for very long. It would start causing a bunch of pain, nerve damage, and a whole host of other issues for the horse.\n\nIf there's any damage to the bone that's also an issue. Horse bones tend to shatter far more than our bones do, making the healing process more difficult, and the chance for compound fractures much greater.\n\nThey're just all around not designed to heal through a lot of injuries well.",
"Healing is often not possible. \n\nThe legs of a horse have no muscles below the knee. Instead they have high tension tendons and ligaments that are controlled by muscles in the upper leg. This means that when they break the bones tend to shatter rather than just fracture and are often so damaged that they cannot be knit back together. But assuming they can be knit back together the lack of muscle means less blood-flow to that part of the leg which means slower healing. This slow healing can cause a lot of problems. \n\nMost Horse breeds are so heavy that they need all 4 legs to support their weight and can only stand on 3 or 2 legs for very short periods of time. So they cannot stay off the leg long enough for it to heal and you have to immobilize the horse in a sling of some-kind to support the weight normally put on that leg. This immobilization is dangerous though as horses who lay down or do not move for too long are prone to developing colic which is a twist in their digestive tract that is often fatal. It is also very expensive to immobilize and tend to the horse during this kind of treatment. So most horse owners choose to not spend the money on something that has a very low chance of actually healing so they just put them down quickly. \n\nA broken shoulder, while likely to heal faster depending on the type of break still has the immobilization issues, risk of colic, and expense of care so with a racing horse being a business investment and not a pet few would ever try and treat such a severe injury. "
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1ja7c3 | why are humans more intrigued by negativity and malice than positivity and good? | Example - News is 90% "And today a 10 year old was shot in the face while..." and 10% "Today a 10 year old was granted the wish to fly to Mars...".
Why is it we want bad, bad, bad and are always searching for it? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1ja7c3/eli5_why_are_humans_more_intrigued_by_negativity/ | {
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"Because \"good\" is supposed to be normal. People generally aren't intrigued by normal.\n\nThink of it this way: \"All planes land safely\" is not newsworthy. And it shouldn't be--that is what is supposed to happen. A plane crash is an outlier, and thus intriguing.",
"Life used to be extremely difficult to survive day to day with tigers and disease and food hard to find. Our brain is still the brain from that time. It has to always focus on the potential dangers and be paranoid in order to survive, and it is very very good at it even though its not as necessary anymore. It's arguably more efficient to be good at riding the positive and spreading it around multiplying it, but we always forget because Neanderthal brain has to watch out for the boogeyman and process every little suspicion. \nTis is also why good news is more boring. We have more tools and processes available to analyze bad news. It's richer and deeper for us. "
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1kgftl | how did single cell organisms evolve into having things like eyes which seems like one of the senses that would evolve out of nowhere? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1kgftl/eli5_how_did_single_cell_organisms_evolve_into/ | {
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"Nothing evolves out of nowhere really.\n\nSIngle cell organisms didn't evolve eyes, multiple cell organisms evolved over a long period of time and some of them ended up having some specialized cells that reacted differently to different amounts of light. We can see organisms today that are like this.\n\nThings simple like that continued to evolve into the eyes that animals have.",
"Well no single cell organism I'm aware of has eyes...\n\nIf you mean how did multi-cell organisms without eyes develop eyes, then you need look no further than still existing deep sea creatures that have what are essentially highly developed freckles that enable them to detect light/dark then move on to slightly more evolved (though still very primitive) creatures that have developed lenses but no corneas etc...\n\nPerhaps the most interesting of all though is to look at the giant squid; which has an eyeball that is almost identical to that of a human (other than, ya know... being the size of a basketball) but which evolved completely independently; which we know because our eyes (and the eyes of almost all living creatures) actually see everything upside down with our brain being used to \"put everything right\" wheras their eyes actually see it right so they can save brain power for more important things like... well, barely having a brain.",
"First of all, there were a lot of steps between single-cell organisms and creatures with eyes.\n\nAlso, the first \"eyes\" were probably light-sensitive cells that gave early creatures a sense of direction (light is up, for example). These cells gradually grouped together, then formed a spherical cluster, and gradually become more and more complex until forming eyes as we know them today.\n\nBTW, eyes have evolved independently several times. For example, eyes in squids have blood vessels on the outside of the back of the eye, as opposed to humans that have these vessels on the inside. This means that a hemorrhage in a human partially inhibits sight, whereas this is not the case in squids.",
"Organisms didn't go *straight* from single-cells to having eyes. There are lots and lots and lots of steps in between.\n\nIf you're interested, though, [this diagram](_URL_0_) shows the basic steps of how we think the eye evolved. \n\nBasically, the organism starts with just a patch of vaguely light-sensitive skin cells. This was a random mutation, but was beneficial because it allowed them to detect changes in the surrounding environment. This then developed into a cup shape to help 'capture' the light better. Then the fluids/tissues start to develop, which gives noticeably greater quality and clarity.\n\nEach individual step is just a minor improvement over the last one. But - in sequence - you get the eye.",
"What do you mean \"evolve out of nowhere\"? I don't get it.",
"Did a church camp just let out this week? This is the third time I've seen this question recently. \n\nPlease don't stop asking. Keep asking questions. ",
" > that would evolve out of nowhere?\n\nThat's the point about evolution... nothing evolves out of nowhere.",
"Evolution is an inevitable yet completely random process. Things like eyes seem so amazing that it must have been designed, but it's just the culmination of random occurrences (mutation) that just happened to be good so it stuck around. Over a period of time, the mutations that just happened to be good or advantageous won over (outlives/outproduces) what was originally the norm. If you repeat this over millions of years, you get some pretty damn incredible things.",
"Humans can see the polarity of light in certain situations too. Google \"haidingers brush\". It works. I've tried it. ",
"An important thing to realize is that visible light is fundamentally no different from any other type of the EM spectrum.\n\nYou know what else is part of that spectrum? Infrared.\n\nYou can *feel* infrared radiation all over your skin, in the form of heat. You can go stand in sunlight and close your eyes, and merely due to its heat, you can orient your body toward the sun.\n\nYou can also light a candle, close your eyes, cup your hand, and identify the general direction and intensity of the flame. It's like having a couple infrared eyes at the end of your arms!\n\nGiven that you can \"see\" certain parts of the EM spectrum using essentially any body part, how difficult is it to imagine specialized organs evolving that can discriminate and resolve other parts of the EM spectrum?",
"Richard Dawkins put it best in his book (and TV special) \"The Blind Watchmaker\".\n\n\"Beginning with a simple organism, capable only of distinguishing between light and dark, in only the crudest fashion, he takes the reader through a series of minor modifications, which build in sophistication until we arrive at the elegant and complex mammalian eye. In making this journey, he points to several creatures whose various seeing apparatus are, whilst still useful, living examples of intermediate levels of complexity.\"\n\nTaken from _URL_0_",
"Starfish have been found to have visual organs without the assistance of a brain. This has been often pointed to as the beginning of the evolutionary chain for eyes. \n\nSource: Vsauce2",
"Single cell organisms came together and evolved into more complicated species. The mitochondria is thought to have external origins and even has its own dna. ",
"Nothing on an organism comes out of nowhere. \n\nThrought mutations, natural selection and enough time, organisms can develop complex features like the brain or sensory capabilty. \n\nStep one: \nan mutation occurs and some cells are now light sensitive\nStep two: \nis it benefitial for the organism to have these new light sensitive cells and can it reproduce more then its brethren that have no light sensitive cells? \n\nSince we have eyes its safe to assume that they are usefull and they start to reproduce more then its light insensitive brethren.\n\nGiven enough time only the light sensitive organism is left over.\n\nGiven enough time a new usefull mutation occurs and the cycle will repeat itself.\n\n\n\nHere are some links you may find usefull.\n\n_URL_2_\n\n_URL_0_\n\n_URL_1_",
"Cool it guys, David Attenborough's got this one:\n\n_URL_0_",
"watch this\n\n_URL_0_",
"Hey OP,\n\nJust a friendly reminder to check the search bar before submitting a question to ELI5: we had a [very similar question](_URL_0_) hit the front page 4 days ago.\n\nWhile very similar and on the borderline of being removed, I've decided to let this post stay up as I think it's ever so slightly different enough to warrant a separate question. Also you've had some good responses from the community, and have some very different explainations than those that came up in the other thread. \n\nHappy redditing :)",
"Read The Blind Watchmaker by Dawkins if you really want to understand evolutionary concepts as a layperson. One of the things that make this so hard for people to accept is that it happens on such incomprehensibly large time scales and involves such incomprehensibly large populations of organisms. \n\nTL;DR A trait that requires a million incremental evolutionary steps, each of which is mutation that has a one in a million chance of occurrence, can easily happen in 100 million years - Not that long in evolutionary terms.\n\nLet's say that it takes a million incremental changes to go from crude light sensitive cell to an eye as complex as our human eye. And let's say that each change has a one in a million chance of happening due to a mutation. Finally, let's say that we have a population of ONLY a million organisms that generate 2 offspring each year then die, but is held at a million through predation, disease, old age, etc. \n\nStick with me here. So every year, 2 million babies are born. This means that in the first year 2 babies have the mutation that is the next step in eye evolution. If every descendant of one of those babies reproduces, it would take about 21 years for the population of organisms with that mutation to reach 1 million. Well, nature is harsh, so let's say it takes 100 years for organisms with that trait to reach a population of 1 million. Let's also say that only then do we see the occurrence of the next step in the process.\n\nStill with me? Using the above assumptions, it would take 100 million years for the eye to evolve.\n\nIf you change the assumption to a billion organisms, it doesn't take as long. \n\nIf you allow a given organism to have more than 2 offspring, it doesn't take as long. \n\nIf you allow that a 1 in a million mutation could happen sooner that every 100 years, it doesn't take as long."
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1qinys | what is the process of remastering old films/movies? also, as a followup, how long does this typically take? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1qinys/eli5_what_is_the_process_of_remastering_old/ | {
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"Strangely, (at least it seems strange to some people) regular old film is extremely detailed, somewhere around 25 megapixels per image. In order to distribute a movie, it gets converted to an easier-to-use format, but this process loses some of the detail. This isn't a problem because if they convert it to DVD, for example, they expect it to be shown on TVs of a certain quality, and there's no sense in going over that.\n\nWhen they remaster a movie, they go get the original film, scan it into a computer at (nearly) full resolution, go over it frame-by-frame to remove scratches and dust, tweak the colors so it looks better, etc..\n\nThe end result is that they can then re-convert it to a new format (Blu-ray, for example) at a higher quality than the original release."
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nlcaz | hardware encryption | How is it different than any other kind of encryption? As a side note, can ANYTHING be decrypted? Or are there some things which are impossibly difficult? (in a reasonable amount of time) | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/nlcaz/eli5_hardware_encryption/ | {
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"The only difference is that the encryption is done with specialized hardware, not with software. Because it is done on special hardware, it is generally faster and can be more difficult to crack.\n\nIf an encryption scheme is done correctly, it will be impossibly difficult to crack in a reasonable amount of time. Even simple methods like RSA are \"impossibly difficult\" to crack if your key size is big enough. However, you have to make sure that your implementation doesn't have any weaknesses that can be exploited.",
"The only difference is that the encryption is done with specialized hardware, not with software. Because it is done on special hardware, it is generally faster and can be more difficult to crack.\n\nIf an encryption scheme is done correctly, it will be impossibly difficult to crack in a reasonable amount of time. Even simple methods like RSA are \"impossibly difficult\" to crack if your key size is big enough. However, you have to make sure that your implementation doesn't have any weaknesses that can be exploited."
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567y74 | do bird feathers decompose? | If so, how long does the process take? If not, why not? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/567y74/eli5_do_bird_feathers_decompose/ | {
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"yes. its literally hair and a soft form of keratin(the stuff your finger nails are made of), so it would take about as long as a finger nail would take to decompose. like around a full year to decompose completely.",
"They do decompose, but the rate of decomposition differs on environmental conditions. Feathers in a compost heap will break down fairly quickly, while, say, a feather in a jar on your counter is good for years and years."
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1ewz2z | last month, yitang "tom" zhang proved the twin prime conjecture, one of math's oldest problems. what is the conjecture and how did he do it? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1ewz2z/eli5_last_month_yitang_tom_zhang_proved_the_twin/ | {
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"He did not prove the twin prime conjecture, but he did prove something that is directly related to the twin prime conjecture.\n\nThe twin prime conjecture is very simple: There are infinitely many pairs of primes that differ by 2. \n\nFor example, 3 and 5 are twin primes, because their difference is two. 11 and 13 are twin primes.\n\nWhat Dr. Zhang proved is that there are infinitely many pairs of primes that differ by a number less than 70 million. It is a fantastic result, and it quite close to the twin prime conjecture... but it is not a proof of the actual twin prime conjecture.\n\nAs for how he did it, it is a little complicated. Basically, he used a weak \"sieve\" (see _URL_0_ for an example of a strong sieve that eventually finds all of the prime numbers) to prove that the pattern of primes obeys a certain set of constraints.\n\nThen he proved that that set of constraints that the primes obey implies that no matter how far you go along the number line, you can always find two primes that differ by less than 70 million. His actual proof is 20 pages long and uses state of the art mathematics that I am neither qualified nor able to ELI5, even though I do have a degree in math.",
"I asked earlier this week when the article made the front page of reddit; What exactly Yitang Zhang proved, and why it was important. /u/corpuscle634 replied with the following answer: \n\n\"Prime numbers get more \"sparse\" as you go up in size. As the article points out, 40% of the single-digit numbers are prime, but only 4% of the 10-digit numbers are prime. This happens because larger numbers are more likely to have other smaller numbers that are factors; for example, even when we only go up to the 20-30 range, there are only two primes (23 and 29), because everything else is divisible by either 2, 3, or 5.\nSo, when mathematicians (and their computers) are trying to find extremely large prime numbers, it gets harder and harder, because there are fewer and fewer the higher you go up. Not only do you have more and more numbers to test (there are more numbers between 1 million and 2 million than there are between 100 and 200), but each number you test is less likely to be prime.\nHowever, mathematicians a long time ago noticed something interesting. A lot of prime numbers seem to be \"twin primes\"; they are separated only by 2. For example, \"3 and 5\" or \"137 and 139\" are pairs of twin primes.\nWhat's neat about it is that twin primes seem to continue to arise even as we get up to absurdly huge numbers; we've found pairs with almost 30,000 digits. That's not a result you'd expect. Since we know that the percentage of numbers that are prime gets lower and lower as the numbers get larger, it's incredibly unlikely that you would find two so close together.\nSo, this leads us to the twin prime conjecture, which is a guess that mathematicians have made that there is an infinite number of these twin prime pairs. It's still not proven, but what Zhang did got us a lot closer. He proved that there's an infinite number of prime numbers separated by some number less than 70 million, while the twin prime conjecture is saying that there's an infinite number of prime numbers separated by 2.\nNow, you're probably thinking \"70 million isn't very close to 2,\" which is true, but when we're talking on the scales of numbers with millions of digits, 70 million really isn't that far from 2 anymore. It's a major step in the right direction.\nIs there any practical purpose to any of this? No, probably not, at least not anytime soon. Prime numbers are used by computers for cryptography (how they keep things secret), but they're otherwise not very useful. Mathematicians just figure this stuff out, and then scientists sometimes are able to make use of it.\""
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3ei431 | how do countries get their names? | Places like America, Britain, Kenya, Mongolia, Russia.
Who names countries and how does the name come about? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/3ei431/eli5_how_do_countries_get_their_names/ | {
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"Every name has its own history. Like all language it is a developing process. For example America has been named accidently by German mappers. They got the maps from Amerigo Vespucci, an Italian who was with Columbus and mapped the american coastline. Now the germans who were copying these maps saw the name \"Amerigo\" on the maps and thought that Amerigo must have been the discoverer, so they named the Land after him \"America\". By the time they noticed their mistake, the name America was already very common and widespread, so they couldn't change it back.",
"Really, they're named for all sorts of different things.\n\n- Some of them are named for the ethnic groups that resided there before modern countries emerged — Britain, probably, for a celtic-speaking tribe that the Greeks wrote about in the 4th century BC.\n\n- Some are named for individuals — America, for Amerigo Vespucci, the first explorer to establish that the land Columbus returned from was a new continent (as far as Europe was concerned) and not part of Asia.\n\n- Some are named for natural features — 'Kenya' was the name for a mountain located there, in one of the natively-spoken languages.\n\nSome countries even have totally different names in different languages. For instance, in English we call it 'Germany', based on a classical term for the tribes that lived there. But the Germans call it 'Deutschland,' which if you trace out its roots literally means something like 'people land' or 'popular land.'",
"Atleast in East Asia, all the names of the countries were named by China. China (中国) literally means \"Middle/Central Empire\" because China viewed itself as the center of civilization in the world. It's exonym, \"China\" came from the Qin dynasty (pronounced \"C'hin dynasty\") or \"Cin\" in Sankrit, or \"Cina\" in India, that's how China got it's name. It gave the name Nihon (日本) to Japan (Portuguese import of southern Chinese pronounciation of 日本) which means \"Land of Rising Sun\" since Japan was east of the \"center\" on the mainland where the sun rises. It gave Joseon (朝鮮) to Korea (when Korean King asked the Ming Emperor for a new name for dynasty, Chosun or Wanyi, Chinese Emperor choose Chosun, which alluded to older Korean dynasty) which means \"Land of the Morning Calm\" as Korea was in between Japan (rising sun) and China. It gave Vietnam (越南) it's name after the Vietnamese King asked the Chinese Emperor for an appropriate name for the country (China opposed previous name 南越, which all alluded to Nam Viet, a former country that China conquered). Also, China named Mongolia after a character that means ignorant, uncultured, and stupid. "
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3anife | why don't meteorologists routinely report dew point rather than relative humidity? | I find dew point to be more useful, and would prefer not to have to consult a psychrometric chart to find it. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/3anife/eli5_why_dont_meteorologists_routinely_report_dew/ | {
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"Most people have a very limited understanding of the weather, and aren't interested in the details. The vast majority of the people want to know, is it warm? cold? sunny or cloudy? and is it going to rain? \n\nPeople who have different work related need for more detailed information such as pilots, farmers, sailors, get a weather report appropriate to their needs. And frankly with the internet, you can get the dew point on any number of weather related websites, or weather apps. \n\nFor example:\n\n_URL_0_"
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2y3qwm | is 'new' dirt ever created? why or why not? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2y3qwm/eli5_is_new_dirt_ever_created_why_or_why_not/ | {
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"Yes. Dirt is made up of three parts: sand, clay, and loam. The first two are basically just rocks, only broken down into really small grains. The distinction between “sand” grains (tiny) and “clay” grains (really really tiny) is kinda arbitrary but it makes a lot of difference for how the soil handles water, and what types of minerals they're made out of.\n\nAnyway erosion is constantly—but slowly—breaking down the solid bedrock into boulders, then rocks, then pebbles, then sand, and so on. Water and gravity move it downhill and, usually in a river flood or something, spread it around as new dirt material.\n\nThe third part, loam, is made up of partly-decayed plant material. If you want the dirt to be fertile and support lots of new growth there needs to be a certain fraction of loam in it. This stuff is also being renewed, gradually, as existing plants die and fungus digests it a little and worms and beetles drag bits underground and bacteria rots it some more and so on and so forth."
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2qousq | why can't i just brush my teeth with mouthwash? | nowadays mouthwash seems to have everything that toothpaste has: flouride, tartar control, breath freshener, etc. i also understand that the mechanical movement of a toothbrush help remove the bacteria on the teeth that cause tooth decay, which is why the act of brushing is important. but why do we still use toothpaste? can't i simply swish around some mouthwash and then use the remainder to brush, then spit it out once and be done? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2qousq/eli5_why_cant_i_just_brush_my_teeth_with_mouthwash/ | {
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"They say it does, and it does definitely help, but brushing will always be slightly more effective for the reason you mentioned, it dislodges material from the teeth. Brushing itself isn't even enough, really. My teeth look great but I used to have irritated gums despite brushing every day. Flossing cleans your gumline, so if you floss and brush you're covered.\n\nI mainly mouthwash if I'm in a rush and don't have the time to brush or floss.",
"I brush with mouthwash at least once a day along with other times using toothpaste. "
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2091d0 | the tv show cosmos seems to have caused a big stir in the us. why is this? | I've seen parts of the show on the internet but have yet to see a full episode, so forgive me if I am wrong here. The show seems to be a nice looking science documentary and doesn't seem to me to be anything revolutionary. Maybe over here in the UK we are spoilt for choice when it comes to science and nature documentaries (Attenborough, Cox et al). | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2091d0/eli5the_tv_show_cosmos_seems_to_have_caused_a_big/ | {
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"Haven't heard anything about people being miffed by it, but it really made renaissance Christians look terrible. ",
"It is a remake of a groundbreaking science documentary series from 1980. Many people have very fond memories of Carl Sagan's original series, and it quite literally inspired many children to become the scientists of today.\n\nWhile we also have no shortage of science documentary shows, we haven't had anything with remotely the same kind of impact that Cosmos did in 1980. We're hoping lightning strikes again.",
"A few main things, as unbiased as I can be:\n\nIt's caused a positive stir among many who appreciate a very well made (and well-funded) science documentary on prime time TV, echoing the late Carl Sagan's groundbreaking show and making complicated scientific ideas accessible to the mainstream community\n\nIt's caused a negative stir amongst several religious groups for a few reasons:\n\n1. The Big Bang, a non-earth centric (or even solar centric) universe, and evolution go against most holy books' literal readings, and religious folk don't want their children, flocks, etc to see that.\n\n2. Neil DeGrasse Tyson is an outspoken atheist and critic of religion, which many religious groups see as threatening to their dogmas\n\n3. A large chunk of the first episode focused on Giordano Bruno, an Italian Renaissance monk and philosopher who was executed by the Church for his belief in an infinite universe. Though it was fairly historically accurate, many Christian groups saw this as an attack on their history."
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70x0rw | apparently, the smell of freshly mowed grass is actually chemicals that grass releases to warn other grass of the oncoming danger. why would this be a thing since there's literally nothing grass can do to avoid the oncoming danger? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/70x0rw/eli5_apparently_the_smell_of_freshly_mowed_grass/ | {
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"They aren't warning other grass.\n\nThe chemicals being released do a couple things.\n\nThey help heal the grass, help seal the grass so that it's a bit more resistant to dmg (doesn't do shit against a steel blade, but helps against a caterpillar).\n\nAnd it can help to call certain bugs that feed on the bugs that feed on the grass.\n\nEdit: Some grasses will also release certain chemicals that make their leaves taste awful to bugs. \n\nSome grasses can also concentrate nutrients into their roots to better rebuild.\n\nre-Edit: for information on the talking to other plants bit \n\n_URL_0_\n\nThe smell may also be a chemical warning to other grass to preemptively taste bad, but its far more likely that other grass is warned via the Wood Wide Web",
"It does not \"warn other grass.\" It attracts parasitic wasps that will kill small insects that are commonly trying to eat the grass.",
"It's also not true that there's nothing grass can do. A plant can push more of its nutrients into the roots, which are more likely to survive whatever danger is attacking the leaves.",
"In addition to what other people said, grass literally lives to be mowed (well grazed). Desertification is due in large part to lack of herbivores (see [here](_URL_0_)). I'm no expert, so I don't know how much that is important w.r.t. lack of water, but it looks like grass has nothing to warn the rest of the grass about.",
"I can't speak for grass, but tomatoes under attack by caterpillars can boost defensive chemicals that make their leaves taste horrible, causing caterpillars to [eat each other instead](_URL_0_) and save the plant.\n\nIncredibly, [some plants](_URL_1_) are capable of ramping up their defences simply by *hearing the sounds of caterpillars chewing*. ",
"I think the premise of this question may be flawed. The smell is a combination of chlorophyll and other fluids being released from the grass when it is cut. Plants typically communicate with other plants via the superhighway of fungal mycelium which live in a symbiotic relationship around the root zone of the plant. The chemical signals being transmitted inside of a fungal network mimic neurotransmitters in the human brain. The warning process actually takes place through the root zone of the plant, aided by fungal symbiosis. Not through the exterior transfer of pheromonal triggers.",
"I'm not sure if grass specifically does this, but I know some plants can withdraw important nutrients into their root systems to minimize the risk of losing leaves or stems to hungry animals, and they do it in response to similar cues from other plants being attacked nearby. So your assumption that \"there's literally nothing grass can do\" isn't necessarily true.",
"Because grass is of cruel nature. Cut grass feeds on the fear of the uncut grass knowing it's going to be cut soon.",
"The chemicals also let the other grass retract their nutrients so they won't lose as much and can regrow more easily. ",
"If memory serves; The smell of fresh mowed grass once saved the life of a Formula one pilot (driver) back in the 60's. The pilot, sorry can't remember, tells the story that as he was at speed approaching a back marker near a chicane or other tricky bit. SMELLED mowed grass! He backed off thinking that was an odd sensation. Cautiously continuing his lap he saw a car off course that ripped through surrounding sod. Driver commented that he too would have crashed into the other car had he not throttled back. was perhaps at Spa or Imola. Cant remember.\n\n",
"Many plants release aromas to attract predator insects. You can test this by isolating a plant like a tomato indoors then shaking it lightly. You will immediately smell it. And if there were any predator insects near by they would swarm in.",
"Well - if there was a lawnmower bearing down on you and there's nothing you can do to avoid the oncoming danger, wouldn't you scream anyway?",
"I think you musta mixed up this idea with another. Which is; in africa the trees giraffes eat release chemical signals to other plants when they are being eaten. The other trees pick up the signal and make their leaves taste very bitter, in turn the giraffes avoid those bitter trees.",
"The smell warns the other grass that \"your ass is grass\", but since grass's ass is already grass, it doesn't care and just sits there doing nothing.",
"People like to think that it's an animal trait to like to stay alive, and protect and defend themselves, and plants are just totally inert. But that isn't true. Unlike animals, plants can't run away and escape danger, but plants are every bit as opposed to being killed and eaten as any animal is. Instead of running, plants engage in physical warfare: spikes and tough exteriors and all kinds of other things, and chemical warfare: releasing a number of different chemicals in response to being attacked by an herbivore. These responses fall into three main categories:\n\n1. Direct defense. Some chemicals released by plants are intended to directly harm the predator eating it. Many plants, such as clover for example, use cyanide as their poison of choice. Sometimes, to prevent poisoning themselves by accident, they'll even compartmentalize their cyanide into a two-part weapon system, storing a harmless, nontoxic cyanide precursor inside their cell cytoplasms, and storing an enzyme in their cell walls that breaks down that precursor into active, deadly cyanide. Getting munched on by a herbivore breaks the cell wall and mixes these ingredients, poisoning the predator. Plants can also harm their herbivore attackers indirectly too, through things like producing an analog of the mating pheremones of the herbivore's natural predator.\n\n2. Local repair. Some chemicals that plants release when they're damaged, such as jasmonic acid, serve as plant hormones that signal the rest of the plant to brace and prepare for damage. Plants constrict their water channels to avoid losing water through their damaged parts, produce saps and sticky coagulants to block off the damage, produce antibacterials and antifungals to protect against infection, increase cell replication to heal faster, and start producing bitter, foul-tasting molecules that discourage herbivores from continuing to eat them, as well as enzymes that block digestion, making itself less nutritious.\n\n3. Remote signaling. Many of the same chemicals that direct plants to start repairing themselves, such as jasmonic acid, are also highly volatile, and signal neighboring plants to start bracing for impact and preparing themselves as well. In response to distress signals given off by nearby plants that are being eaten, plants will produce bitterants and digestion-blockers, making themselves unpalpatable to their herbivore predators. In fact, this is the reason that giraffes have to be nomadic creatures: you never see a giraffe herd strip a tree completely bare, because after munching on a tree for some time, the tree becomes bitter and inedible, and depending on wind conditions, other trees for miles around become so too. So the herd has to keep moving, trying to stay ahead of the chemical cloud of anguished screaming their leaf-munching inspires, in order to keep finding new trees which are still delicious and haven't yet hardened themselves.\n\nOf course, plants can't tell the difference between an animal's teeth and a lawnmower's blade, so against us, all their chemical screams, poisons, and distress calls don't do them much good, and make a pleasant summertime perfume for us instead.",
"Wait, that smell isn't actually a phosgene counterattack? ",
"Weird thought but why do we like the smell of freshly mown grass? Is it possible we evolved to recognize when a grazing animal had chomped through so we learned to associate the smell with food and thus \"smells good\"?",
"There is an interested documentary on this topic about a desert ecosystem in Africa, where they saw a declining population of an animal, I believe it was similar to an antelope. They would eat this certain tree and as a defense the tree would release a toxic chemical in the leaves and in the air which would poison the antelope and also act as a warning to other trees. So if a nearby tree sensed this chemical in the air, it would also release this chemical, causing it to be toxic temporarily. It was never a problem until a severe draught hit and the only food source left for these animals was these trees. In essence, the trees began killing all of this population and no one could figure out why the populations were declining so fast. It took a long time to figure out the defense mechanism of these trees.",
"Actually, the grass chemical smell is meant to attract predators that will eat the bugs that are eating the grass. It's natures way of grass screaming for help because something is murdering it.",
"This is also why predators (such as ourselves) enjoy the smell of freshly cut grass. The herbivores eat the grass, the smell attracts the predators, the predators eat the herbivores and the herbivores feed the grass with their body. ",
"I've read that in certain circumstances these VOC's (volatile organic compounds) that are responsible for creating these smells can act as a call to arms for certain types of actively defensive flora. For example, once a tobacco plant receives stress signals from a plant being munched by some animal, it'll create noxious odors to discourage further grazing. ",
"Most plants will have a defense mechanism where they concentrate nutrients in a certain part of the plant. So while the leafy part of the grass can't do anything to avoid damage, it can send all it's nutrients and moisture down to the roots so it can quickly grown back.\n\nTrees do this every year when they shed their leaves. A tree will stop sending water and nutrients to the branches in order to survive winter.",
"i believe this is related to a mechanism that signals the grass to send its moisture to the roots",
"Nothing it can do YET. Give that grass a few million more years of evolution and it's gonna fuck your shit up as payback for all those years of mowing.",
"they can not defend themselves but they can make changes, they can push nutrients down into the root, saving them for later repair work, they can start closing down capillaries to protect liquid flow and they can release flavonoids that are bitter to put off animals from eating them",
"Does The Happening come to anyone else's mind?",
"It is called - the SAR response in plants - systemic acquired resistance - it's why cannabis has trichomes, to ward off animals from eating it. When the plant comes under stress, natural or forced, the plant produces more resin and higher THC percentages, to a point. \nThe SAR response in grass is smell which triggers the same response in non-cut grass to send phytohormones towards the shoots to prepare to repair itself. \nSource: cannabis farmer",
"Also: ELI5: why do I love that smell?",
"I read a thing about trees doing this- where the warned trees change the chemical makeup of their leaves whereby the taste becomes more bitter and therefore less appealing to the attacking insects.",
"a natural disaster like a tornado or a quake is near you and you can't do anything to stop the damage. You still yell to get help and warn others. Life is life, whether its yours or grass's.",
"There are things the grass can do to avoid extra damage from the oncoming tragedy even though they can't get up and walk away:\n\n-it can start storing extra energy in the roots\n\n-it can slow the uptake of water from the roots so it heals faster after damage\n\n-it can increase production of nutrients after to repair faster\n\n-it can release chemicals to heal open wounds\n\n\n... while it can't move it can help prepare for danger... like someone in the path of a hurricane fixing up their house with plywood over the windows.",
"Plants can do release chemicals to inform other plants of oncoming danger, however, I don't believe that is the case with grass.\n\nWhen the others plants get this \"communication\" from the damaged plants, their flavour changes so as to become less desirable for the approaching herbivore.",
"Fuck. I'm too late for this. But there is a **really interesting** radiolab episode on a topic similar to this - I would argue it actually is this topic as well. But they mention how trees at the edge of a forest will propagate chemicals through the roots to the other trees to tell them that beetles/insects are coming. The trees in side the forest begin to excrete a chemical that makes them taste bad to the insects so they don't get eaten. \n\nHere is the episode link: _URL_1_\n\nNotes: _URL_0_\n\n\n",
"The selection pressure is not on the plant releasing a warning. The selection pressure is on other plants to be aware that neighbors are being hurt and to respond accordingly. In some cases neighboring plants detect chemicals released by neighbors that are injured and then begin to manufacture chemical defenses to ward off an impending attack. Wild tobacco for example are known to do this.",
"but if you want a legit answer, the chemicals attract animals that naturally feed on grass, thus it's like a symbiotic relationship, grass located food for predators and the predators in return protect the grass indirectly ",
"Plants can't move, but they *can* react. We animals are *so obsessed* about moving, but that's not the only kind of defence.\n\nSome defensive plant chemicals cost the plant a lot of energy to build, so building/prepping them constantly isn't an efficient plan. It's like constantly outfitting yourself with new suits of body armour long after the war has ended - costly and unnecessary, at a time when energy needs to be spent elsewhere. Better to wait and live normally, and suit-up after the warning alarm is raised. \n\nThese grass signal chemicals are just that - a warning alarm, telling the plants nearby to get toxic/distasteful. Some other volatile chemicals act as deterrents to insects, like a bad smell. Still others have been known to attract the predators/parasites of plant-eating insects. [This article](_URL_0_) discusses a number of these scenarios.\n\nWhen you're stuck in one spot and can't move quickly, it seems you have 3 options: become gross, smell gross, or call in the enemies of your predators. Maybe even all three at once ;)\n\n",
"This is part of the reason i loved the movie The Happening. It is based on the premise that trees \"talk\" to each other for various reasons... Except it goes more deadly. I find the concept facinating, and its definitely a horrifying possibility - that trees could literally kill us via chemicals and we couldn't avoid or detect.\nIts an awesome movie and I highly recommend it if you don't mind a few shitty scenes of Marky Mark and Zoey Deschanel badly acting because the movie might be awesome but the script lacks fulfulled potential. Seriously though, watch it. ",
"explanation: so other grass can start synthesizing such chemicals in preparation for what´s about to come, thus being able to warn neighboring grass.",
"generally it's not to avoid the mower...they didn't evolve in a time when mowers existed, instead it's to deal with insects, the process of releasing chemicals when cut, or bitten, triggers other plants in the area to release chemicals that deter or kill insects that would eat them.",
"So M. Night Shamalan is finally trying to understand his own movie \"The Happening\" and created an ELI5?",
"Plants will release certain chemicals to try to attract predators that eat whatever is feasting on the plant at the time. This is a sound theory and it's been discussed a few times here in this thread so I won't rehash it. Here's my argument:\n\nHumans don't eat grass.\n\nHumans really like the smell of fresh cut grass.\n\nHumans eat the animals that eat grass.\n\nWhen grass is cut (eaten) it releases a chemical into the air to try and attract Humans to hunt the animals eating said grass.",
"Oh grass can't do anything? Watch the Happening.",
"Am I not in Explain like five or am I supposed to have a conscience and actually wanted to die, it still would have evolved many herbivory defenses and are more likely to survive winter."
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"http://podcastnotes.org/2016/09/20/radiolab-from-tree-to-shining-tree/",
"http://www.radiolab.org/story/from-tree-to-shining-tree/"
],
[],
[],
[
"https://www.wired.com/2013/12/secret-language-of-plants/amp"
],
[],
[],
[],
[],
[],
[],
[]
] |
||
7ckxr9 | why does molasses spoil while honey doesn't? | By my understanding, Honey is so concentrated in sugar content that it sucks water out of the bacteria.
Wouldn't Mollasses do the same? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/7ckxr9/eli5_why_does_molasses_spoil_while_honey_doesnt/ | {
"a_id": [
"dpqpivh",
"dpqq0rh",
"dpqw0pp"
],
"score": [
4,
7,
2
],
"text": [
"Sure, but honey has more sugar than molasses does, as a result the effect is worse for the bacteria in honey than molasses and more can survive in molasses. ",
"It's a threshold issue: A fluid compound need 20% water to support bacterial growth. Molasses is about 25% water whereas honey is about 17-18% water. That's is why Molasses will 'go bad' but honey will not. ",
"Not totally related; but in a way honey does \"Spoi\". It ends up killing bacteria on the surface, not letting them grow but collecting dead ones. This is why you shouldnt give babies honey, as they can get botulism"
]
} | [] | [] | [
[],
[],
[]
] |
|
2ci64h | hypothetically, if the rotation speed of earth started to accelerate, is there a speed at which we would be thrown into space? | What would be the effects on the planet, and life here, as the rotation speed exponentially increased ever more each month? (Would we feel dizzy? What would kill us?)
*I did search, but as far as year back I couldn't find something like this (these) question(s)* | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2ci64h/eli5hypothetically_if_the_rotation_speed_of_earth/ | {
"a_id": [
"cjfp1yv",
"cjfp6p4"
],
"score": [
7,
2
],
"text": [
"I highly recommend this: _URL_0_",
"If by magic the planet started to accelerate like that, and also by magic it held together at those speeds, yes, our perceived weight would gradually reduce, and eventually cross zero and you'd find yourself beginning to float slowly up. You'd be in orbit just a tiny bit off the ground.\n\nThe thing that would kill us is that as we were becoming weightless so too would the air be, and long before any solid or liquid things went into on-earth orbit all of the air would blow away. The depressurization would also freeze everything the surface of the earth."
]
} | [] | [] | [
[
"http://what-if.xkcd.com/92/"
],
[]
] |
|
ake5k9 | if an independent game studio goes under, who/which company owns the intellectual properties? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/ake5k9/eli5_if_an_independent_game_studio_goes_under/ | {
"a_id": [
"ef43zqs",
"ef446y7"
],
"score": [
3,
2
],
"text": [
"When a company shuts down, it generally sells all its assets off to recoup as much money as possible. That includes whatever copyrights and other intellectual property it might own. So the rights are owned by whoever bought them when the company shut down. This is how you get things like the Atari brand being owned by various companies over the years.",
"If the shutdown is by choice of all the shareholders, all assets of the company, including intellectual property, will be distributed among them based on their shareholder percentage.\n\nIf they declared bankruptcy, then all the company assets will be put under a trustee and auctioned. So the owner will be the highest bidder of that aution."
]
} | [] | [] | [
[],
[]
] |
||
xnute | why don't smartphones (or any cell phones for that matter), when using its autofill/autocorrect feature while you're texting, detect over time which words you use more often and stop prompting is to correct the words we never use? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/xnute/eli5_why_dont_smartphones_or_any_cell_phones_for/ | {
"a_id": [
"c5o06ro"
],
"score": [
13
],
"text": [
"In some cases, they do. For example, the SwiftKey keyboard for Android analyzes not only the way you use it, but also your most commonly used words and phrases in your emails and social networks.\n\nHowever, in general, it's better to base predictions off the population of word usage as a whole, rather than trying to optimize a system just for you. It allows other people to use your phone without being surprised, and it allows you to go to another phone with ease, and not have to retrain your new phone.\n\nThe fact is that the majority of usage is going to fit into the standard rules of the existing autocorrect systems, and exceptions can be easily programmed. For example, if I correspond with my friend Jones a lot, and don't want his name to keep getting corrected to \"jokes\", I can add his name to the dictionary of words that are commonly used, and my phone won't try to correct it again."
]
} | [] | [] | [
[]
] |
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