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74owj3 | why honey never expires | Repost | explainlikeimfive | {
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"It's high in sugar and low in water. Bacteria, like all living things, requires water to survive. Honey has so little water that it will pull water out of any bacteria and kill it. Also, too much sugar is also a good way to kill bacteria. If all the bacteria that get on the honey die, there's none left to produce any of the hazardous byproducts that make food go bad and expire.",
"Others have already commented on the low moisture and low water activity being the primary method of preservation. To add to this, bees naturally produce small amounts of hydrogen peroxide when they break down the sugars. Hydrogen peroxide both inhibits growth and can kill certain types of bacteria and fungal spores. Source: Am food scientist",
"As others have said, it's the lack of water and resulting osmotic effects that is the primary cause. However, when compared to concentrated sugar solutions, honey has even more antibacterial effects. So there are additional naturally occurring compounds to preserve honey as well.",
"Bacteria and mold need moisture to grow - honey has effectively no moisture so it doesn't spoil when properly stored. It can last for centuries even.",
"Life requires water. Honey doesn't have enough water content to support the growth of microbes.",
"The lack of water preventing bacteria/mold from growing. Also, honey is mostly stable sugars. They don't break down in that environment (assuming a lack of light and heat) so it doesn't go 'rancid' or nasty.",
"Why can’t we use honey as an antibiotic then?",
"So my honey in my cupboard that is old and crystalizing is not \"bad\" I just can't use it because I can't get it out of the jar?",
"Doesn’t oil also not contain water yet that can go bad?",
"Perfect spot for a question I've had. My hubby brought home a number of jars of honey that had been sitting for an insane amount of time in his grandparents old house. I want to say somewhere in the vacinity of 12+ years. The stuff looks almost black and it's all solidified at this point, but all the containers have lids on them, so they haven't been open to the air. I think it's all raw honey too. They have beekeepers that use a bit of their land for their hives, and as payment, they give them raw honey, so I'm assuming this is from them. It's still ok? The hubby makes beer and meads and such, and was thinking about using this for his meads."
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74qwek | What exactly does Cos, Sin, and Tan, measure in a triangle? | Repost | explainlikeimfive | {
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"They are the ratios of sides of a right triangle. So you've got a right triangle, and one of the non-right angles is marked. The sine of that angle, for example, is the length of the side opposite (across) from it, divided by the length of the hypotenuse. The ratio of the side next to the angle and the hypotenuse is the cosine, and the ratio of the last combination (the opposite and adjacent sides) is the tangent.",
"URL_0 I always drew this for my students when they came in for tutoring. Literally any problem they had from precalc through calc 3 I started drawing a unit circle. Often they would tell me they knew it but we always used it more than once.",
"If you know one angle and one side of a right triangle, they tell you the length of the other sides. Let's say you want to know how high your drone can fly. You place it on the ground, pace out 50 feet, then fly it to maximum height. You measure its angle above the horizon to be 75^(o). That's all you need to measure its height: Adjacent side = 50 feet Angle = 75^o tan(75^(o)) = opposite / adjacent tan(75^(o)) ~= 3.7 3.7 = opposite / 50 feet 187 feet = opposite Similarly, we know the drone is 50 feet / cos(75^o) = 193 feet directly away from you,"
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74xjg0 | as a non-american, what are HOAs? Every story I've ever heard about HOAs in America makes them out to horrible, petty and just all around pointless. What is the point of a homeowners association? What do they do other than bother people? Are there non-horror stories? | Repost | explainlikeimfive | {
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"They're Homeowner's Associations. When you buy a house or condo, if an HOA has been established in the community, you're essentially contractually forced into paying some amount of money each month to fund the HOA, and you agree to follow the HOA's rules. The HOA then typically uses that money to maintain and upgrade common areas like private parks, sports courts, pools, etc. in the neighborhood. The HOA may also enforce rules on what your home looks like form the street. The goal of an HOA is to maintain higher home values through these public spaces and home appearances, which can definitely be a good thing. Too often, though, the HOA leadership becomes petty people on a powertrip, which is where the horror stories usually come from.",
"I like our HOA, for the most part. We live in a condo complex so we have common areas such as pool/hot tub, grassy area, landscaping, etc. which need maintenance. The HOA is also responsible for the outside of our condos including roofs, etc. We've had the HOA pay for a contractor when we had termites. They do have rules about what kind of front doors we have and of course we wouldn't repaint the outside (there's no obvious divider on the outside between ours and our neighbor's condos) but our HOA is not that intrusive. Dues have actually gone down while we've lived here.",
"In a planned community, a homeowner's association manages shared resources. In a condominium building, for example, the HOA will be responsible for maintaining the outside of the building, the hallways, and the lobby. They also can pass rules about what homeowners in the community are allowed to do with their homes. If you live in a rowhome for example, you probably will not be allowed to paint your part of the outside bright pink with yellow polka dots no matter how much you want. There are certainly plenty of communities that take it too far, but most of them are just the homeowners pooling resources for the upkeep of their homes."
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753st0 | Why is it that in small vehicles (cars, etc), seat belts are present and required - but in large passenger vehicles (buses, limousines), they are not present? | Repost | explainlikeimfive | {
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"A large vehicle isn't going to stop suddenly from high speed unless it hits something similar size or bigger which is much less likely. It's less likely to be travelling at high speed anyway. It's got more bodywork to crumple and spread out much of the impact over a period of time."
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755d01 | Entropy of space | Repost | explainlikeimfive | {
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"If you have a glass of water at 60F, in a room that is 70F, energy from the room will exchange with the water, and eventually you will have water and room at the same temperature (slightly less than 70F, given a completely closed system). Space is the same. Imagine that all of space consists of one star. Space is 0 degrees K and the star is 6000 degrees K. Eventually the star will burn up all of its fuel, and die. Over billions of years the heat energy of the star will dissipate into space, and the space will be a uniform temperature again."
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755ect | Why does feces end up being a brown color most of the time? And if it ends up a different color, why is that? | Repost | explainlikeimfive | {
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"Yarr! Yer not alone in askin', and kind strangers have explained: 1. [ELI5:Why is poop almost always brown? ]( URL_4 ) 1. [ELI5: Why poop is brown ]( URL_5 ) 1. [ELI5: Why is it that the stool is always the same brown color (almost) regardless of what we have eaten, and same thing with urine. But if we eat beetroot both feces and urine becomes red? ]( URL_0 ) 1. [ELI5:Why is poop brown? ]( URL_6 ) 1. [ELI5: Why is feces always (generally) the same color regardless of the food you eat? ]( URL_3 ) 1. [ELI5: Why is poop brown and not blue or pink? ]( URL_2 ) 1. [Why is poop brown? ]( URL_7 ) 1. [Why is poop brown? ]( URL_1 ) 1. [ELI5: Why is poop brown? ]( URL_8 )"
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75bkb2 | why do voices sound high pitched when sped up? | Repost | explainlikeimfive | {
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"This has been answered accurately already so I'm gonna try to do a better job of explaining it to a 5 year old. When you talk, there are \"strings\" (not actual strings, more like folds) in your neck called vocal cords that make the talking sound. The faster they move (or vibrate), the higher the sound they make. Children's voices sound higher than adult voices because children's vocal cords aren't as big, so they're able to vibrate faster and make a higher pitched sound. The same thing happens if you take that sound and play it even faster. You're artificially making the vibrations of the sound move faster so it sounds higher pitched. This is true of any sound, not just voices. ***Edit***: In case I simplified too much... here's a longer answer for anyone who wants to go a bit deeper, or who wants to complain about slight technical misunderstandings of what my simplified explanation meant: When vocal cords are smaller they naturally vibrate faster when air is pushed by them, which means the frequency of the audiowave pattern they produced gets repeated quicker. That's the frequency, which determines how high we hear its sound. The faster something vibrates, the higher pitched it is. You do the same thing when you take a recording and run it faster. You increase the frequency of the audiowave pattern, so the pitch gets shifted up. So the \"Explain it like I'm 18 and just haven't taken physics for some reason\" answer is that in audio, pitch = frequency, and frequency = wavespeed / wavelength. If you speed up the wavespeed without changing the wavelength, you get a higher frequency, which equals higher pitch. But that answer had already been given when I wrote this, so I went for something a little more illustrative, and a lot of people seemed to find it more helpful. ***Final edit*** For accuracy I adjusted some words and added some notes in parentheses. I originally talked about the length of the vocal cords instead of just overall size, which, while accurate, is not AS accurate, and just seemed to confuse the issue.",
"Pitch is determined by the frequency of the sound waves. When you speed up a playback, it shortens the duration between the sound waves, resulting in a higher frequency and thus a higher pitched sound.",
"> Pitch, noun: the degree of inclination or slope; angle. As in \"pitched roof\". When you have waves like this: _ _ _/ \\_ _/ \\_ _/ \\_/ \\_ with time along the bottom axis, and you squeeze the time, you get this: /\\ /\\ / \\ / \\ / \\/ \\ So you've **literally**, by the above definition, increased the pitch.",
"The pitch of a sound is based on its frequency. When you're speeding up a sound, you're doing the same amount of \"sound waves\" in fewer seconds. e.g, you've increased the frequency.",
"Everyone has explained frequency and /u/AssaultedCracker even brought up vocal cords, but nobody has explained why bringing up the frequency makes things sound *unnaturally* high pitched (not just as if a singer were singing higher), so let me cover that. When we talk or sing, the sound we produce is made by two things: first, the vocal cords make a pitch, or a basic tone. Then the rest of the inside of the mouth and throat *filter* that sound, emphasizing some parts (frequencies) and getting rid of others. This is how we can tell vowels like \"e\" and \"o\" apart: the basic pitch may be the same, but by moving our mouth and tongue we change the resulting sound that comes out. If you've ever brought a glass or cup to your ear and listened as you move it closer and closer and eventually seal it off, you've experienced filtering. The cup changes which frequencies are emphasized or removed and things sound strange. In general, males have larger \"filters\" (mouth and throat) than females and kids have smaller ones. The larger the filter, the lower the general frequencies. This is why male voices sound deeper and kids' voices sound higher pitched. The range of the vocal cords also changes, but a guy and a girl may be singing the same note and yet the guy will still sound deeper on average. The interesting thing is that when we sing higher or lower the basic pitch changes (the note our vocal cords make), but the rest stays the same: the filter still filters the same frequencies. But when we speed up a recording, we're not only changing the base pitch but also everything else, including the effects of the filter. And so, slowing down a recording of a woman makes her sound more like a man, and speeding it up makes her sound more like a kid. And if you go high enough, it'll start sounding like a Smurf, which is what we've come to associate with unnaturally sped up human voices. This component of speech besides the base pitch is called the *formants*. Speeding up audio shifts the formants up higher in frequency. And that's why speeding up a voice makes it sound funny and high pitched. Specialized software (like Melodyne) can be used to edit this, changing the pitch of a voice without altering the formants or the tempo, or any other combination of those. For example, GlaDOS from the Portal games is a female voice that was edited to \"autotune\" the pitch but also with the formants shifted higher to make her sound oddly childish and robotic. Similarly, the stereotypical \"bad guy voice\" in games is often just a voice with the formants brought way lower with digital editing.",
"I have a question on that, can you keep the same pitch but speed it up?",
"1. frequency means how often something happens 2. sound is made up of frequencies 3. speeding up sound means increasing frequency 4. increasing frequency is raising pitch now if your question is why pitch increases with frequency its similar to asking why some frequency of light is a certain color: it just is, based on the medium the waves are in",
"Though it is correct that faster playback pushes pitch upwards, an additional important aspect is that the formant areas of the voice (the resonant areas of the voice which distinguishes the tone from a male and female singing the same notes apart) is also pushed higher, making it sound chipmunk-y when sped up or beast-y when slowed down.",
"Corollary question: Is this related at all to the doppler effect?",
"Sound is made by shaking. If shaking is slower, sound is lower. If shaking is faster, sound is higher. If you take a slow shake, and speed it up, the shaking is faster, so, the sound is higher.",
"Let's do this: try to tap water with your finger in the same spot keeping some tempo. You will see that you create circular paths around your finger. That circular path, is a wave, which has highs (the highest point of the wave) and valleys (the lowest point of the wave) Now, sound is a wave. Try to tap in the water by moving your finger in some fixed direction (=on a straight line): you will see that the valleys of your waves are approaching in the direction you are moving. If you don't have water around to try the experiment, here you are a [video]( URL_0 ) Okay so, we said sound is a wave. A wave has a frequency which is \"how many valleys that wave generates in a second\". So, when you tap without moving your finger, the wave you are generating has a fixed frequency BUT the waves you generate moving your finger, has an increased frequency on the direction you are moving and a decreased frequency in the opposite direction because, valleys are going further from each other. Higher frequency = higher sounds Lower frequencies = lower sounds There you go :)"
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75k0mr | How does clicking a box to confirm you're not a robot stop robots? | Repost | explainlikeimfive | {
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"The captcha isn't checking that you clicked the box. But how you clicked the box. What was the path of the mouse cursor movement. What was the delay in movement. What was the speed of the movement. What were the initial and ending coordinates Applying heuristics, it can give a confidence level if it matches any known bot clickers. And your data is compared to all other human and bot clickers to see if you are a bot clicker",
"What's actually being measured is the way your cursor moves towards the box, how quickly it moves, and how quickly/accurately it clicks the box. Humans tend to move the cursor imperfectly, and this is what the pop-up expects. You can make bots that move the cursor more organically, yes, but this tends to filter out the majority of low-effort bots.",
"It takes note of your browser user-agent, time you spent on that page, your mouse movement inside the box etc. If it's still suspicious, you have to do an image recognition task, which is not simple for a computer to do."
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75klnq | How does pain medication such as advil or tylenol “know” where the pain in your body is and how do they then go about counteracting it. | Repost | explainlikeimfive | {
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"Pain medicine works systemically. It does not \"know\" where pain in your body is. Various pain medications work in different ways. We're still not sure exactly what Tylenol (acetaminophen/paracetamol) does. Advil (ibuprofen) isn't a great painkiller, but it is really good at reducing inflammation, which can cause pain in itself. It does have some relatively minor pain-relieving effects as well. It attacks [the enzymes that cause inflammation.]( URL_0 )"
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75n9us | How do birds (especially pigeons) determine what is edible and what not? | Repost | explainlikeimfive | {
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"Experience, just like humans. As children, we frequently attempt to eat pretty much anything that's put in our general vicinity. Some things taste bad, some things are hard, some things are tasty. We quickly learn which things are tasty, and focus on those things as a food source as we grow up. We also get additional information from our parents and peers, who eat things around us and may feed us as well, adding to our experience of edible foodstuffs. Pigeons, other birds, and other animals learn through the same process."
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75ntx8 | Why aren't the computer keyboard letters placed in alphabetical order? | Repost | explainlikeimfive | {
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"They tried to do this for typewriters originally but people were too fast and jammed the mechanisms. They switched to qwerty and it and stuck since."
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75rm6p | How did cartographers create accurate maps prior to the days of air travel? | Repost | explainlikeimfive | {
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"First: they simply weren't as accurate. Second: surveying. Pick a point, measure the distance and direction to some other point. Repeat until you have lots of points, and make a map with that info.",
"There is an entire branch of engineering known as Surveying. These are the guys you see out on the side of the road with tripod looking things. George Washington trained as a surveyor when he was young. Basically you start from a known point, setup your equipment, and have another guy hike to Point B with a long stick. He stands there with the stick and you look through your equipment and note the angle, height, and distance between A & B. Then you move on to point B, he goes to point C, and your repeat. Do this enough times and you have the data you need to draw a map, using a little Trig to help you. The equipment has a gotten fancier (lasers are used for accuracy) but the basic concepts are the same."
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75svu9 | How does alcohol make you drunk? | Repost | explainlikeimfive | {
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"When you drink alcoholic beverages, the ethanol (responsible for making you drunk) gets absorbed from the stomach to the bloodstream. The liver will break down ethanol up to just carbon dioxide and water in a long complex process, meanwhile some of the ethanol will pass through our cells in our brain if the liver has its queue full of ethanol waiting to be broken down. Ethanol has an interesting perk that can depress the neurons responsible for tasks such as motor function, speech, etc. This makes the intoxicated feel \"liberated\" or \"sluggish\". however once more of ethanol enters your brain it gets worse; nausea, vomiting and unconsciousness are the common symptoms of alcohol intoxication. That's the simplest of how alcohol can get us intoxicated. TLDR: when you drink too much, unprocessed ethanol can get to your brain and interfere with the cells there, making you groggy and have slurred speech as some of the common side effects.",
"The main thing in alcohol that has an effect is [ethanol, or ethyl alcohol]( URL_0 ), a surprisingly simple molecule, especially compared to most other drugs. Beer is about 3-10% ethanol, wine is 10-15% ethanol, and liquours are about 40% ethanol. Ethanol gets absorbed into your bloodstream, and from there can pass easily into your brain. Once in the brain, it has a **ton** of effects. The biggest one is probably activating a type of protein on nerve cells called a GABA receptor, which essentially \"turns the neuron down\" (makes it less likely to activate). Another major one is that it blocks another protein called an NMDA receptor, which tends to activate neurons--so by blocking it, it again turns the neuron down. Like everything having to do with the brain, exactly how we go from that to the effects we notice is insanely complex and not completely understood. For various reasons, it tends to \"turn down\" neurons in certain brain regions more than others. It hits the cerebellum (at the top of the back of your neck), which is important in controlling your movement. It hits your prefrontal cortex (right above your eyes) pretty hard--and that's an area that's involved in \"higher\" functions like planning and decision-making. Most seriously, it also affects your brain stem, which is the part of our brain that controls little things like our heart continuing to beat, our lungs continuing to breathe, maintaining consciousness, etc. The ELI5 version: imagine your brain is a giant company headquarters office building filled with thousands of workers in different departments. Alcohol is like a computer virus that gets into the network and starts making the computers in a bunch of different departments run incredibly slowly and crash."
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75tdbl | What is the differences between Hepatitis A, B, and C? | Repost | explainlikeimfive | {
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"The hepatitis viruses (including D and E also) were identified in a time when biologists and medical professionals knew very little about viruses, or where able to classify them appropriately. The word hepatitis means \"inflammation of the liver,\" so naturally this is what all the hepatitis viruses have in common. They all cause some form of inflammation in the liver which leads to symptoms that are similar. Hepatitis A is in the picornavirus family of viruses, same family as polio. It's an illness that people get by drinking or eating contaminated foods (this is refered to as fecal-oral transmission) often in third world countries where sanitation is poor. It looks and feels way worse than it is, lasting only one month and almost never killing anyone who gets it. Hep B is a member of the hepadnovirus family. It's transmitted through sex and needle sharing, making it a blood borne pathogen. It looks much like hep A at the onset of illness, resolves, but unlike hep A which has no carrier state, hep B has a carrier state which often times develops into chronic hepatitis (chronic liver inflammation) over the course of many years, and often presents with kidney failure and even liver cancer. whether or not this occurs depends on the persons immune system. Unlike hep A, when we find hep B infections we treat them aggressively with antiviral medications. Hep C belongs to the flavivirus family, same as West Nile virus. It is transmitted only through blood, which makes it most common in people who share needles. Unlike hep B, hep c infections become chronic most of the time, leading to liver cirrhosis (hardening) and also liver cancer, same as hep B, but much more commonly. Infact, hep c is the most common cause of hepatocellular carninoma. We treat hep c as we do hep b, but cannot vaccinate against it (as with hep b) because the virus itself is too variable in the way it coats its outer shell. In summary, the hepatitis viruses are not a family of viruses. They are a group of viruses from different famililies that all happen to affect the liver in some way.",
"They are caused by different viruses and therefore cause different illnesses. While they all cause \"hepatitis\" or inflammation of the liver, they are far from the only viruses that cause that. EBV (the most common form of \"mono\") also can. As can CMV and other viruses...as well as many non-viral causes (autoimmune diseases, Fe overload, tylenol toxicity, fatty liver, alcohol, etc). Speaking in broad strokes, Hepatits A tends to be transmitted through a fecal-oral route...meaning fecal contamination of food or water and is typically ingested. It often causes a brief illness that most people get over from, but can be dangerous to certain groups of people. Hepatits B is a virus made from DNA (the other 2 are RNA). It is usually sexually transmitted. It can also occur through blood-borne transmission (transfusions, sharing needles for IV drug use) and in some cases can even be passed from mother to child during pregnancy and birth. Unlike Hepatitis A which usually is only a transient illness, Hepatitis B can lead to immunity in some people, but other people can develop chronic disease which can eventually lead to cirrhosis or liver cancer (\"hepatocellular carcinoma)\" Hep C is usually transmitted by the blood borne route. Most people do not develop immunity to it and have chronic infection which ultimately leads to either liver cancer or cirrhosis. There is no vaccine for Hep C but there are new drugs that can kill the virus. Meanwhile, there are vaccines for HepA and HepB.",
"From my experience Hep A, wasn't nearly as bad as you'd expect. I somehow managed to get Mono (EBV) and Hep A (as well as tonsilitis and pharyngitis) at the same time, ended up in hospital for a week. My only real symptoms of EBV and Hep A were hot feverish sweats and headaches from EBV like a severe cold/flu without coughing and sneezing etc and yellow itchy skin coupled with really strong smelling brown urine and white excrement. Sleep was not my friend for about a month, thats to say uninterrupted sleep - even now 3 months later I can't get enough rest - what I wouldn't give for a good 12 hours sleep a day. The only reason they kept me in hospital was to make absolutely certain my liver recovered ok and that there wasnt some kind of underlying illness on top. For anybody interested both the hospital and my personal Dr seem to think it was caused by my work, I'm a broadband, and phone technician. I go into people's homes to fix faults, I used to have drinks sometimes when offered - not these days. Also I have to work in manholes in the street but take precautions but could also be that somehow. This was probably about 3 months ago and I am still struggling with energy levels at work and home - about 1 or 2 in the afternoon I'm ready for a nap.",
"Just to add, while Hepatitis B is transmitted by blood contact, it is extremely transmissible via this route. An outbreak in Sweden among cross-country runners was tracked to a Hepatitis B carrier who was among the faster runners - small cuts on his legs from grasses/flax and twigs provided a means of infection for following runners. In New Zealand, there is a high endemic rate of infection among Polynesian groups due to maternal infection of babies who generally develop chronic Hepatitis B infection (95%). This impacts the general population, with \"playground infection\" a common infection vector. I've been involved with treatment trials for chronic Hepatitis B, and there have been some really positive developments."
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75ztw4 | How do we know how much humans contribute to climate change when the Earth has always had vastly fluctuating temperatures? | Repost | explainlikeimfive | {
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"I don't think we could ever say with 100% confidence how much of climate change is because of human action, but we can draw reasonable conclusions. As an example, we can see and measure very clearly that carbon emissions and other greenhouse gasses trap heat in the atmosphere. We can also see and measure how we are producing those emissions. We can also see and measure that there is a strong correlation between our emissions and the rising temperature. We can also use other measurements to see what the atmosphere has looked historically and compare that to where we are now. From those measurements and observations (in addition to other measurements and observations) conclusions are drawn. If we know that there is a strong relationship between carbon dioxide in the atmosphere and global temperatures, *and* we know that we are producing record amounts of carbon dioxide, we can reasonably conclude that our emissions are contributing to rising global temperatures. There is obviously some debate about how precisely we can measure our emissions and its relationship to the climate, but we can tell very clearly that we are responsible to a high degree (no pun intended). One of the best visual examples of how we know how much we're contributing is in this comic: URL_0",
"Well, we can look at rates of change compared to historical fluctuation. Turns out, temperatures are rising higher and faster than we see in any of the \"natural cycles\" of which we have records (and we *do* have records, thanks to things like ice-cores. Science is *cool*). Combine this with the close correlation between increased greenhouse-gas emissions and climate change, also visible from historical records, and with the fact that we know the effects greenhouse gases can have on small scales, and you get some pretty strong evidence.",
"We can look at patterns of what we think the temperatures were like in the past (using things like ice cores in Antarctica which traps \"atmosphere\" from the past). We see gradual changes over the thousands of years, and then very sharp changes in the last 150-160 years. Changes that would have taken thousands of years in nature. We haven't been manually recording temperatures for very long. Since about the industrial revolution, which is where we usually get concerned with human activity on the environment (as things changed dramatically regarding what we put into the atmosphere and water)"
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762lp7 | whats the difference between soap and body wash? | Repost | explainlikeimfive | {
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"Bar soap is a detergent (cleaning) chemical that remains in solid form at room temperature, and doesn't immediately dissolve when put in running water. Body wash is also a detergent, but its chemical form is more like shampoo in that it's pre-dissolved in a small amount of water. Because it's already dissolved, it's more convenient in a number of ways, but less convenient in some others. The conveniences are that it can be spread and turned into bubbly foam much more easily than soap can, and manufacturers can load it up with additives like strong scents and ingredients like skin conditioners that a bar of soap just can't hold. And because its packaging is permanent, you don't have to deal with grody, slimy hair-covered bars of soap that have gone a little soft and are shared with other people. But the compromise is it's more expensive as a liquid to package and ship, and you go through it a lot more quickly due to the water content so you end up buying a whole lot more.",
"Also, body wash creates a lot less soap scum in the bathroom. Went to boot camp before body wash wash became popular (1998). My RDC (drill Sgt for those not familiar with the term) forced us to only buy prell shampoo for use as both hair and body cleanser. He did not want to see a bar of soap anywhere. Reason being that the prell did not create soap scum and we passed inspection more often. another fun fact....barbasol shaving cream is great for cleaning showers and the bottoms of shower shoes.!"
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767x8w | SSRI's reinforce depression | Repost | explainlikeimfive | {
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"There's a couple problems with this. Firstly, the model that depression=low levels of serotonin in your brain is oversimplified and certainly not wholly accurate. For one thing, we don't have a way to measure the levels of serotonin in living subjects. In addition, some people with depression likely have normal and even above-average levels of serotonin in their brains. Secondly, drugs like SSRIs increase the concentration of serotonin in the brain right away--but their effects on mood don't manifest themselves for weeks later, after a whole series of cascading reactions happen in the brain, which probably include reducing the number of receptors for serotonin making the increased serotonin less effective than it was initially. Secondly, you would have to find some drug that binds to a target which causes the brain to increase its amount of serotonin production in order to test this. When pharmacy identifies a drug which is effective for some condition, most research in that area goes into refining variations of the drug that have better efficacy, safety and reduced side effects, rather than looking for entirely new drugs (cost much more with much less likelihood of attaining benefit). There are certainly some ground breaking new drugs out there, but that isn't where most new drugs come from."
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76byq7 | How are games cracked? | Repost | explainlikeimfive | {
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"The executable files of a game are basically just a bunch of machine code. Machine code are instructions executed by your computer. By using a so called Dissassembler, you can turn the machine code into a somewhat human readable format called \"Assembler language\". If you are good, you can then analyse the code and modify to circumvent copy protection mechanisms, e.g. by taking the copy protection code out or jumping over it.",
"Crackers basically change the inside programing of it For example : If a game has an online protection (that requires to be online to be played), they'll modify the code, to make the game think that you are actually online. /u/dale_glass also answered this 2 years ago :) > Some games come with code that makes it hard to run a copy by just possessing the data for it. For instance, it may make you enter a serial number. You copy the CD fine, install it, and it asks you for the number. You don't know it, so the game refuses to work. > Well, somewhere inside the game there is logic like this: > Ask user for serial number > Perform some operation to check the number. For instance, all digits should sum up to 9. > If the answer is right, continue > Cracking is just interfering with this logic. You can modify the code to jump past the verification step. You can make it still ask for the serial number, but accept any number at all. You could flip the logic around so that it accepts only invalid numbers. Etc. > This was the early era of cracking. Then the companies started making things more complicated. The program may be encrypted and self-verifying, so not only you need to break the encryption and make the change, but also find how it checks itself and defeat that as well. > Some are more devious and don't make it obvious that they know something is wrong. Instead the game runs, but breaks something subtly in such a way that the 5th level becomes impossible to finish. > Any kind of protection is breakable, but with enough effort it's possible to make something that requires considerable thought and time to get around, and it's quite possible that if the protection is good enough the game will remain uncracked for months. Hope it helped ;)"
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76bznf | How were the Buddhist monks who self immolated able to show no pain at all? | Repost | explainlikeimfive | {
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"Many of these monks are able to achieve a meditative state, which allows them to focus to a seemingly superhuman degree. Often, when consumed in flames that are hot enough, the nerves near the surface of the flesh are burned quickly, so the pain would be very intense, but relatively brief. Following nerve-death, shock sets in, which causes a flood of chemicals to the brain, some of which block the sensations of pain coming from still-living nerves, and some of which trigger a fight-or-flight response. The combination of uncommon focus and the physical effects of shock, adrenaline, etc make the monks appear calm and apparently in no pain. There have been many self-immolations recently in south east Asia, and if you look at the (shocking and upsetting) photographs, you see that most of them light themselves and immediately begin to run around, flailing and panicking. Most of these recent immolators are not monks, and not practiced in meditation and mental focus. They run because their fight or flight response to the pain of burning causes them to try to flee the danger. Running while in flames can provide some relief, clearing the face and airways of smoke and heat, so the victim may remain conscious longer, having inhaled less of the hot gasses and smoke, and more of their nerves remain intact and responsive for longer, causing greater levels of shock and higher, more prolonged pain. The famous monks are absolutely in terrible pain, but their mental training allows them to better tolerate the response to pain. Coupled with the fact that they remain motionless, the fire consumes their flesh and nerves quickly, they are overcome by inhaling hot gasses and flame, and their systems begin to shut down and succumb to the trauma more quickly and \"consistently\" than people untrained in meditation. Simply, they show no pain because they have trained to tolerate pain. Control over the body's response to stimulus (physical and emotional/mental) is a central purpose and goal of most Buddhist meditative traditions.",
"The real answer is opium, although the Buddhists would claim that those monks could withstand pain just by entering a deep meditative state.",
"Basically, we are extrapolating from a single case of Thích Quảng Đức in 1963, which is the only case I am aware of that was captured on film. We have no idea if others ran around screaming. In his case, it was likely combination of mediation and strong will, possibly with drugs thrown into the mix. Also, while obviously it is going to be extremely painful, the pain might not last very long. If you covered your entire body with an accelerate, the initial shock of all those nerves firing at once could last long enough for asphyxiation and nerve killing third-degree burns to set in. It might be harder to suppress the horror of your mutilation and impending death than the pain itself."
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76dg9o | Why does cold water taste better than warm or room temperature water? | Repost | explainlikeimfive | {
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"Basically, because the cold further stimulates the receptors on your tongue that can tell if your drinking, and make you feel hydrated."
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76girz | How does radiation cause cells to mutate? What is actually happening to them? | Repost | explainlikeimfive | {
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"Radiation physically damages your DNA, which can cause cells to replicate improperly. Imagine having a blueprint for a house you want to build, but you accidentally light part of it on fire. You now have to build the house with part of the blueprint missing, and even if you use your best guess as to what was in the blueprint before, there's a very good chance you'll end up building the house wrong.",
"Ionizing radiation can cause energy to be absorbed by electrons. Because electrons are involved in chemical bonds, this can cause chemical bonds to break and/or new chemical bonds to form. If this happens to DNA, it damages DNA. Cells have various ways of repairing DNA, but this doesn't always perfectly fix the problem. So, you can end up with a cell with changed DNA. Changes in DNA can have various consequences, like cells producing proteins which are changed from their normal arrangement, and function differently."
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76gjtu | Why does alcohol work as a sterilizing agent? | Repost | explainlikeimfive | {
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"Alcohol breaks down a cell's wall, and the cell falls apart. Imagine a liquid that when poured over a balloon just destroyed the rubber part of the balloon. Then all the water and such pours out and the cell is thus killed, and this works on nearly all cells (not 100%, but roughly 99%)."
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76hzi2 | Why, in humans, are males generally larger than females when it is the opposite in most other species? | Repost | explainlikeimfive | {
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"Humans, like most non-human primates, have sexual dimorphism in which the males tend to be larger than the females. Some primates (like chimpanzees and bonobos) see the males almost twice the size of females. Sexual dimorphism appears in body size, muscle mass, canine teeth, craniofacial structure, and even sometimes deepening voices. There are very few primate species that have reverse dimorphism (females larger than males), so it appears to be \"normal\" that humans display the same dimorphism that other primates \"typically\" have.",
"Females are larger when mating is just about finding the female and doing it. Males are bigger when you have to fight other males to mate. Being big is expensive, its easier to be a spider that has to catch a couple of flies to reach sexual maturity than it is to be one that has to eat hundreds. Males just need to mate. Make some spunk and fire it up the ol' baby hole. So they just get to the point they can spunk and then they want to use all energy finding some strange. Females have to make babies, which is super hard, and the bigger you are the more bigger stronger babies you can have, so females want to be big. However, if you're a male that has to round up a harem of ladies, you have to be big enough to fight off the next bozo who wants your ladies. Or you have to be big enough to steal the ladies from the other bozo, so being bigger makes you better at kicking Chad's arse and stealing his Stacey. Human/prehumans evolved under a system of tribal harems, with common raiding for mate stealing and rape. So you have to be able to be bigger to defend your cave Stacey's from Chad-Ugg's, otherwise you're getting cucked. Our own system is rather unique but similar mate protection systems exist with larger males, gorilla, lions are famous ones. And there's loads of male competition examples too.",
"Fighting. In species where males fight each other to gain access to females, the males will be larger. Do humans be fighting each other at the club to try to \"win a girl\"? You bet they do. There is a wide range of sexual dimorphism in the animal kingdom, with many examples of both males and females being larger. Females can't be too small because they usually still have to give birth to the young. One of the most extreme is with angler fish where the female is much larger. The males are not much more than swimming reproductive organs."
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76i19b | If electricity speed is about 300,000 km/s, why does ping of internet depend so much on the distance? | Repost | explainlikeimfive | {
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"Imagine that all cars, freight ships, trucks, and airplanes would move at light speed. Now think about how long it would take to send a package around the world. Of course it would be faster now, but it wouldn't come close to the speed of light. _Moving the package_ would take almost no time, but the package would still spend a significant amount of time being inspected, loaded, unloaded, etc... This is essentially how the internet works, too. Many of the same words are used here as well: traffic, package, destination, route, ... The information _moves_ at light speed, but spends a lot of time being _routed_ or even queued. Just like you don't have a dedicated road to every person on earth, data packages have to manoeuvre through a network of shared connections. Imagine you're a router in such a network and you receive a package labeled with the destination \"216.58.207.78\" and you're connected to five other routers. You're gonna have think about where to send this for a bit unless you would want to send it to all of your router friends, which would make the internet wildly inefficient. On top of that, as several people already pointed out: When looking at the scale of the earth the speed of light suddenly becomes significant. Going from Los Angeles to Berlin at light speed will take 31ms. Go back and forth (that's what a ping does) and you're at 62ms. That's already enough to ruin most online games. The overhead from routing roughly doubles the travel time, so in practice you would be working with a ping of around 124ms, which will make the game feel like you're wearing oven mitts. EDIT: As /u/HakushiBestShaman pointed out, the information doesn't actually travel through the cabel at light speed, but quite a bit slower [at around two-thirds light speed]( URL_0 ). Taking that into account it seems that the overhead from routing is quite low for long distances along _common_ routes, e.g. US < - > EU.",
"The speed of light is 300,000 km/s (in a vacuum), the speed of an electrical signal in copper cabling is probably closer to 120,000 km/s, and there are things like drift and collisions that present problems. When you are sending a signal across the internet, that signal isn't just travelling in copper. If you're on WiFi, it's first travelling through the air as a radio signal. Then it's hitting an access point which will likely convert the signal to copper. Then it will probably go to the cable modem, which will transform the signal again so that it can travel across coaxial cable to the neighborhood junction. From there it shifts again in shape and enters the cable provider's network. That's still copper until it gets to a point where it's reasonable to have laid fiber and reasonable to splice into it. The signal is converted again, but this time it's blended with other traffic. Who knows how many hops from there until it reaches a network bridging point between providers, then across the adjacent providers network until the desired endpoint is reached. All this combining and converting signals is problematic. All sorts of things can happen along the way to mess up the message. Anything from regular old drift to radio interference to electromagnetic interference to stinking cosmic rays or just bad luck. So there's a language that all of these components speak at layer 1/2 to help ensure that the communication is clear and reliable. (layer 1 is the physical layer, e.g. the actual components, layer 2 is the data link layer, basic electrical communication is defined at both levels). Then there are the things that happens at level 3 - the network layer. This is the routing and switching. These are the \"hops\" you see on a traceroute. Kind of. Basically, these are the components that send all the right signals in all the right directions, put everything into packets, do all the sequencing. We think about TCP/IP as sort of the base level of communication, but that doesn't even start until layer 4. At layers 1, 2, and 3 there's all kinds of groundwork that needs to happen before TCP/IP can even be a thought. All of these different components need to have connectivity. They need to know about each other. They need to have a common language. All of that means signalling. And that means signalling on the same set of connections that your data is travelling through. We think of a web request as data going to the server, data coming back from the server. No... At layers 1, 2, and 3 there is a lot of off-band bidirectional communication so that everything along the way knows what is what. You don't want to send signal down a dead path. You want to prefer shortest pathways. You need to be aware of other potential pathways. You need to know what language the other components of the network speak. You need to tell them about you. All of those bi-directional conversations... well every bidirectional stanza effectively doubles the length of the path a signal has to take. Now when you get to Layer 4, there's TCP/IP. The reason so much of the internet uses TCP/IP is that it's a reliable protocol. Lot's of extra communication happens to get something going. Starting a connection means Syn - SynAck - Ack. That just tripled the distance required. Within TCP, messages are cut into chunks of transmission sized data. Intelligent endpoints will inspect those chunks and do things with them along the way. It could be resequencing (not every packet comes in order). It could be rejecting. It could be forwarding. It could be re-packaging and sending along. It could be re-packaging, splitting, and sending on. The decision for what to do takes processing power and time. Every \"hop\" you see in a traceroute has these decisions to make and adds time to the transmission. It can also mean requests for re-transmission, again doubling the signal distance (actually, potentially multiplying the distance by 5). Then you move up the layer stack and guess what? More bi-directional communication at each layer (there are 7 layers, we haven't talked about the session, presentation, and application layers at all). And let's remember too that when you send a message to grandma's house 3 miles away, the actual phyical paths that a message travels could be anywhere between 5 miles and 700 miles or more. If each layer multiplies the travel distance of a signal by 5, you are now at 39,420.5 km travelled. Yeah, that's a tenth of a second, but that's only the first transmission. Now that connectivity is established each consecutive communication has less distance to travel and all of those devices along the way can work faster now that they've worked things out. Still, all of those devices have work to do and the more devices (and the less clear the signal to those devices) the more work has to get done. But that's not really the amazing thing. A signal isn't travelling at all. No single electron makes it's way from one end of the pathway to another. What you've done is told one electron to dance, and it's told it's nearest neighbor to dance as well. And so on and so forth. Consider that there are 3 trillion atoms in a spec of dust. And of course there are several electrons in each atom. Lay that out end to end over tens of thousands of kilometers and you have interacted with a number of atomic particles that you cannot even fathom. All by pushing a button on a keyboard. And we live in the one special place in the universe with the right temperature, the right combination of elements, the right amount of gravity, the right amount of everything that makes it possible for you to cause all of those little pieces of universe to bend to your will as if you were waving a streamer like a gymnast. And you live in the one special place in the universe where life was generated intelligent enough to figure all that was necessary to build this structure out AND had the motivation to do it. Billions upon billions of cubic miles of nothingness and your particles just happened to end up in the right spot so YOUR BRAIN could make the decision to tell the other person on the XBox Network \"you are a good shot!\" It's very much a miracle that any of this happens at all. One little blip. One meteorite that hits at a different time or at a different angle at the right time in history and we're all bits of moon rock desperately trying to stay still and do nothing. Or you know... some other reason. I don't really know for sure.",
"It's also noteworthy that the speed of light isn't the same in every material. Optical fibers lower the speed by a decent percentage (~30%), and many common copper data cables (cat 5/6) can be even worse. See URL_0 Interestingly, optical fibers _wouldn't work_ if the speed of light in them wasn't significantly lower than the speed of light in air/vacuum.",
"The latency comes more from the various bits of hardware the signal has to pass through, than from the wires. Even so, if you're going halfway around the world at the speed of light without detours, that's 20,000 km / 300,000 km/s = 66 ms (edit: in each direction, so the ping time would be +133 just from distance) which is already a pretty respectable ping time.",
"For the same reason it takes only 4-5 hours to fly from Los Angeles to Chicago, but you can sit there waiting for a connecting flight in Denver for 4 more hours if there's no directs available.",
"The other answers deal with why latency exists, but I would like to add that electricity does not travel at the speed of light through a vacuum, through wiring. It's varies from 50-99% of that. Still extremely fast, so the limiting factor is still computers receiving, retransmitting, and calculating and all that. Now if satellite is brought in to the picture anywhere, there's actually a lag solely because of the travel time to and from the satellite. Not a problem for most connections, but those with satellite internet can't avoid a minimum lag from that.",
"First of all, the electrons making up electricity do not move at that speed. They absolutely CRAWL along. You are talking about the speed of energy transmission, a bit like a line of billiard balls. The balls tap the one ahead and the energy moves forward. OK, not a perfect analogy, but enough to get the gist. If it were only just the transmission of the initial energy that reached it's destination, then you could measure the distance and using the speed, work out the time involved. BUT..... as others have described, there's a lot of crap going on during the journey and it is THAT which slows everything down.",
"Lets think about what you said. You say that electricity travels at 300,000 km/s and you seem to be suggesting that if that's so fast it shouldn't effect internet speeds. Internet speeds (ping) are measured in milliseconds (ms), so sending a data packet 300,000km would be 1000ms and 300km would be 1ms, which is pretty quick.",
"Ping is just no a single light that is bounced back. It's certain types of packets that are processed and forwarded by routers. There are no single long cables between all the computers, but many central hubs where a huge portion of the traffic travels. For example there are only couple of connections across the atlantic. Every time a packet is received at the router, it is in a queue and eventually processed. This adds up with long distances.",
"Questions like this allow me to feel confident in my job Security. My parents told me the next generation of children will all be computer whizzes so I better study hard because they are born with devices and master them. Today I realize just because a lot of people know how to drive it doesn’t mean they know how a modern internal combustion engine works.",
"One part of the problem is, the speed of light is 300,000 km/s **through a vaccum**, such as outerspace. The speed of light drops when going through a medium (e.g. Water, atmosphere, fiber optic cables, copper cables)",
"ping ≠ propagation delay. The latency experienced is composed of many different components. Processing delays at different network layers are accumulated. Of course if you compare a satellite link to optical fibre connection you will see a massive difference as the physical layer latency of a sat link is larger an order of magnitude. Routing and forwarding delays are a significant factor. To experiment, traceroute different countries that are geographically close but use different routes. Traceroute will show you the route and corresponding delays. If you are in Europe for insance compare pings of two websites from Iran and Japan. You will see the effect of physical length of the cables might be superseded by topology of the network in some cases.",
"-The circumference of earth is 40075km. -The speed of light is 300,000km/s. Let’s say you set up a light fiber directly for two locations between the earth without any other router. The light needs 0.1335 secs to travel there and back, or 133.5ms. That’s too ideal and signal will be weak without enhancement, weak signal will make lots of errors. That’s the physical barrier we can’t breach unless we can control something faster than light. Communication between computers is not simply ‘hello’-‘goodbye’, computer still needs to think and check, it’s more like: -‘I have send 50 encrypted packages to you and some might got stuck in a crowded server at France, please check up’ -‘Ok ummm, who are you again? Ok I’m decoding, I got it and I checked there are 49 of them, please send the #29 again’ So that will take some time. All added up, you can expect 10ms read messages, but light in fibers travel in 0.7 light speed, that will take 190ms. It’s 200ms, The real latency is around this. You see, no matter how fast you can read and how servers getting better, the latency will always be there, mostly the light is still not fast enough."
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76i668 | why is there this thorny thing on my ice cube? | Repost | explainlikeimfive | {
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"they are called ice spikes im sorry I can't explain it myself, but this video will definitely do URL_0"
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76idf1 | How come in English we capitalise the word “I” but don’t do so for “a” or other personal pronouns such as “you”? | Repost | explainlikeimfive | {
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"According to [ URL_1 ]( URL_0 ) it used to be lowercase. Then, people started writing it a little bigger likely because it looked funny all on its own. Eventually, people started to capitalize it."
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76jq5h | why is it when we yawn sometimes we start to get teary? | What's the connection? | Repost | explainlikeimfive | {
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"Because when you yawn your faces scrunches up and squeezes your tear ducts which are also installed in your face."
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76jzx3 | Does every single car in the world have a unique key? | Repost | explainlikeimfive | {
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"> Does every single car in the world have a unique key? No. There are too many cars and too few combinations. It is possible for the coded chips to have a truly unique combination but the physical keys are reused.",
"No they don't GM used to only have about 50 different unique key cuts and about 10 resistor values within the keys. So thats not that many unique combinations. (500) Honda had a key until quite recently with 8! Different keys which worked out about 40,000 different keys but they made about 4,500,000 cars in a year so there were a lot of identical keys.",
"I had a 1977ish Mercury Monarch that had the same key as my Dad's brand new 1986ish Ford LTD",
"No, they repeat keys. My sister and I accidentally stole someone's car after we had just had an argument with the person. Her key worked to open and start the car. I think they were both 99' Toyota Camrys. We figured out a couple miles down the road when we noticed a backpack in the back seat and went straight back. He had called the cops on her and they just laughed it off.",
"All international trucks use the same exact key. We have several in our fleet and we all just have a key and it works any truck, including the rentals we occasionally get.",
"I accidentally opened up another rx7 one day. Don't know the maths, but the random occurrence made me think there shouldn't be too many of those 🔑"
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76nddv | Why does our voice sound different to us than to other people? | Repost | explainlikeimfive | {
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"I'll type fast because your post will be removed. Your voice is carried by your skull bones to your ear. Skull bones carry sound a little differently."
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76ppys | How did colonists communicate with natives of the country | Repost | explainlikeimfive | {
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"They start with the basics. For example, Antonio Pigafetta, an Italian who travelled with Magellan, interviewed members of several indigenous peoples that the expedition encountered. Using gestures and pointing, he would prompt them to tell him their languages' words for simple concrete objects - \"sun\", \"leg\"', etc. - so that he could write them down, and then (at least in a few instances) gradually work up to more abstract words. Exchanges like these in other times and places enabled some people from both populations to learn the other group's language well enough to serve as interpreters and laid the groundwork for more intensive studies of indigenous languages later on.",
"Gestures and actions, mainly, until some people started to understand the language well enough to start communicating that way. It's perfectly possible to learn a language without any help from dictionaries, vocabulary lists and grammar books, and the living proof of that is literally every single person on earth. Everyone was born without knowing a single language, but you learned it just through exposure. As long as the people are willing to try and communicate with each other, they will eventually be able to understand."
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76r9y8 | why did the sky in NE England go dark for about 20 mins this afternoon? | Repost | explainlikeimfive | {
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"Storm Ophelia has picked up lots of dust from the African desert and it's all blowing around in the sky. URL_0"
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76rswn | why can’t your Download/Upload be the same speed? | Repost | explainlikeimfive | {
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"It can, and for commercial internet connections they often are. Those are symmetrical connections. But most home users download far more than they upload, so the connections are skewed to reflect that. These are asymmetrical connections. If you have 20 Mb down and 2 Mb up, you may be thinking that \"hey, I'm getting robbed of 18 Mb upload speed\". That's not it at all -- you have a 22 Mb connection, and instead of getting 11 Mb down and 11 Mb up, it's configured to give a (far more useful to most people) 20 Mb down and 2 Mb up.",
"It definitely *can* be. Here are a couple reasons why there may not be: * Your ISP limits your upload to prevent congestion and misuse of their network. * Your computer may not be capable of sending out data as quickly as it can receive it.",
"Most internet connections can be thought of as a highway with multiple lanes. You can have each lane going whichever direction you want, but you can't have cars (data) travelling in different directions on the same lane. ISPs realized that people download a lot more than they upload, so they made most of these lanes be download lanes."
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76zdfc | If a toy drone was hovering in a train carriage, would it hit the back wall when the train started moving, or would it stay in the same spot? | Repost | explainlikeimfive | {
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"While the train is accelerating, the drone will lurch backwards toward the back of the train. Once the train reaches constant velocity, the drone will stop moving (relative to the train)."
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76zm1k | Why do most species have breeding seasons but humans don't? | Repost | explainlikeimfive | {
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"This is because in their environment, there are only a few times a year that \"allow for the optimization of survival of young due to factors such as ambient temperature, food and water availability, and changes in the predation behaviors of other species\" There is no special month that makes it better or worse for humans. We have no predators, and food + water is available all year round.",
"Most humans and their relatives (apes) don't have a specific mating season. The climate the apes live in doesn't really have drastically different seasons with varying levels of food availability, which often dictates other animals mating seasons. On top of that sex and mating are integral to primate social dynamics, especially with humans, Bonobos, and Chimps. Lastly humans and Apes have some pretty damn long infancy spans, meaning no matter what you're gonna have to take care of offspring throughout the year anyway.",
"We do. Its called Christmas break. Ever wonder why all kids have birthdays in late August to October these days?",
"Humans evolved in the tropics, so it didn't matter what time of year you had children. One month was as good as the next. Animals that evolved in more temperate regions had to time their births so that their children were able to survive the winter."
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7754dt | Why do horses wear shoes if wild horses don't? | Repost | explainlikeimfive | {
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"URL_0 > Many changes brought about by the domestication of the horse have led to a need for shoes for numerous reasons, mostly linked to management that results in horses' hooves hardening less and being more vulnerable to injury. In the wild, a horse may travel up to 50 miles per day to obtain adequate forage. While horses in the wild cover large areas of terrain, they usually do so at relatively slow speeds, unless being chased by a predator.[4] They also tend to live in arid steppe climates. The consequence of slow but nonstop travel in a dry climate is that horses' feet are naturally worn to a small, smooth, even and hard state. The continual stimulation of the sole of the foot keeps it thick and hard. However, in domestication, the ways horses are used differ from what they would encounter in their natural environment. Domesticated horses are brought to colder and wetter areas than their ancestral habitat. These softer and heavier soils soften the hooves and make them prone to splitting, making hoof protection necessary.[4] Consequently, it was in northern Europe that the nailed horseshoe arose in its modern form. > Domesticated horses are also subject to inconsistent movement between stabling and work; they must carry or pull additional weight, and in modern times, they are often kept and worked on very soft footing, such as irrigated land, arena footing, or stall bedding. In some cases, management is also inadequate. The hooves of horses that are kept in stalls or small turnouts, even when cleaned adequately, are exposed to more moisture than would be encountered in the wild, as well as to ammonia from urine. The hoof capsule is mostly made from keratin, a protein, and is weakened by this exposure, becoming even more fragile and soft. Shoes do not prevent or reduce damage from moisture and ammonia exposure. Rather, they protect already weakened hooves. Further, without the natural conditioning factors present in the wild, the feet of horses grow overly large and long unless trimmed regularly. Hence, protection from rocks, pebbles, and hard, uneven surfaces is lacking. A balanced diet with proper nutrition also is a factor. Without these precautions, cracks in overgrown and overly brittle hoof walls are a danger, as is bruising of the soft tissues within the foot because of inadequately thick and hard sole material.",
"Horses in the wild don't carry heavy loads, and aren't asked to traverse rocks and pavement. URL_0"
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7754gb | Why haven't we yet found a cure for HIV/Aids | Repost | explainlikeimfive | {
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"As I understand it: HIV’s genome is made of RNA. In order to infect human genomes, it has to first be transcribed into DNA. It accomplishes this via a protein called “reverse transcriptase.” Reverse transcriptase has a very high error rate. It makes a lot of mistakes. Because of the high rate of errors and the high rate of reproduction of HIV-infected cells, there’s a lot of mutations that are different but still functional. That means that HIV has a lot of opportunity to mutate in a way that makes our treatments no longer effective. That’s why most AIDS patients are on what they refer to as a “cocktail.” It’s not just one treatment. It’s like 5 or 6. So if their particular strain starts to develop an immunity to treatment A, they’re still affected by treatments B through E. That said, there technically is a “cure” for it. A small subset of the population has a natural immunity to HIV. Their immune cells aren’t susceptible to infection by HIV. By chance (I think), one of those people donated bone marrow to someone who was HIV positive. Bone marrow is the place in your body that makes immune cells. The donated marrow began producing HIV-resistant immune cells. Eventually, the patient was AIDS-free. However, bone marrow transplants are very dangerous and risky, and have high rates of failure and/or patient death from complications. So while there is technically a cure, it’s not a very useful or viable cure. It’s not terribly worth it considering that the HIV treatment cocktail has become very good and effective and most HIV patients live longer and have a better quality of life compared to bone marrow transplant recipients.",
"I'm seeing many comments on here that diseases are kept infectious because they're 'profitable.' Please take off the tin foil hat. I am a medical research scientist and I can tell you, the massively talented team I'm in work extremely hard to combat illness and improve survival rate. Sure, unfortunately some treatments for illnesses are not manufactured. This is due to a cost-benefit analysis of the medication. A costly to produce treatment for an uncommon illness, or treatment that may not be hugely successful or it doesn't improve survival rates much, will not be marketed. Even if there is some evidence it works. Unfortunately that's the way of it. Whenever we get the red light on a product line, we all think 'but if my mum had this illness...and companies have shelved a cure...' But we need to move on and focus on a treatment for an illness that's extremely common: HIV/cancer for example. Not only would this net massive profits for the company that have put in sometimes hundreds of millions into R & D, but it will save, or improve, countless lives. If we produced medication at a loss, we'd go out of business. And then there'd be no more cures for anything. The cost of medical isn't the cost of producing it, that pales in comparison to the cost of developing and approving it. Recently we did an animal trial on 3 pigs. The cost? 1.8million GBP. To show something we already knew. Add that on top of a 3 year project which has already cost in excess of 30million and you'll see where the cost comes from. And if this product doesn't make it to market, the losses also have to be recouped from somewhere. I.e. Another product line.",
"Thanks for the answers everyone. Very informative and a great read! :-) I've heard that most people with HIV can live relatively normal lives thanks to the development of drugs in this field. In fact, I think I remember reading that the levels of HIV in the blood of positive people is so low that it's virtually impossible to pass it on. Is this true?",
"First, the distinction between HIV and AIDS. HIV (human immunodeficiency virus) is the virus that is transmitted between people and that causes AIDS. HIV likes to infect immune cells (or certain types of immune cells), which are the cells that are called to action to get rid of (or clear/resolve) an infection of any kind. AIDS (acquired immune deficiency syndrome) is a set of rare/unusual diseases that can occur in HIV-infected individual when the HIV virus has destroyed a certain amount of immune cells. AIDS is pretty preventable, if using the right medications. Most people with HIV can avoid progressing to AIDS if they're taking the right medicines and if they're taking their medicine properly. [This is thanks to antiretroviral therapy (ART)]( URL_0 ). So far, HIV itself can be controlled but not cured. A lot of commenters have touched on important aspects of HIV that make it hard to fight. However, it is important to note that HIV, as a retrovirus, integrates into the genome of the cells it infects. What this means is that once it gets into a cell, HIV takes its genome and puts it into the genome of the cell it is infecting. This means that, for that particular cell, HIV is now part of the DNA of the person. (This only happens in infected cells and it does not happen to \"germline\" cells, so you can't 'inherit' HIV in the way you would inherit, e.g., eye colour). This is different from other non-retroviral viruses, which by-and-large remain outside of the host genome. It is currently very hard (read: impossible) for any methods we have to determine which cells have this little HIV stowaway and which ones don't. This is all aggravated by HIV's preference for certain immune cells. Essentially, the cells that are responsible for clearing viruses are the targets of HIV infection. This is bad at first because when an HIV infection starts, these cells rush to the site of infection to try to limit the spread - and this ends up making it worse. As time goes on, HIV destroys these immune cells; this weakens the immune system so that it becomes unable to protect the body against HIV (and, in the context of AIDS, it becomes unable to protect the body against all sorts of things that immunocompetent people never have to worry about). The answers provided by /u/wittymcusername and /u/burhunk are also important, but I think you should also keep in mind that HIV isn't like a lot of other viruses - once it is inside a cell, it becomes essentially indistinguishable from the host by inserting its genome into the host's genome. The [person cured of HIV]( URL_3 ) that was mentioned by /u/wittymcusername was only cured because his immune cells (in which HIV lives) were destroyed (by radio/chemotherap) for the stem cell transplant he received ([because he had acute myeloid leukemia]( URL_1 )). I don't think this would ever be done in the case of an HIV+ patient that does not have acute myeloid leukemia because radio/chemotherapy for cancers are very damaging in themselves. Also, this man was lucky to be compatible to someone with an HIV-resistance - not everyone could have received stem cells from this donor. Even if you did want to use this as a \"cure\", you would need a lot more donors with the HIV-resistance phenotype (called \"delta 32\") than there actually are. If it makes you feel better, there are hardly any cures for any viral diseases ([Hepatitis C]( URL_2 ) is the only one I can think of off the top of my head; maybe rabies, although I'm not sure whether to count it as a cure). Most resolve on their own (by the action of the immune system), or never resolve. Some of these viruses do infect immune cells, but are different because they do not integrate into the genomes of these cells like HIV does. Vaccines are usually the best approach to combat viruses. They are not a cure exactly, but they prevent an infection from happening in the first place. Why *vaccines* don't work for HIV (so far) is a different story - this relates more to what other commenters are saying about high error rates and a disguised shell (/u/Its_just_a_Prank-bro). Basically, HIV changes too quickly for vaccines to keep up. This is superficially similar to how you need to get a different Flu vaccine every year. Edits: removed an extra period and corrected \"Acquired immunodeficiency syndrome\" to \"Acquired immune deficiency syndrome\" (thanks /u/jeffbaier)",
"Great question! To put it simply: When HIV infects a new cell and inserts its genetic material into the cell’s DNA, it has two choices. It can start making more viruses right away (this is what happens the majority of the time) or it can choose the sneaky option. The sneaky option is to do nothing. Inhibitors (HIV treatment) can find cells making HIV and stop them, but they can’t do anything when a cell’s only sign of being infected is a little bit of virus DNA. These cells that have the virus DNA that aren’t actively making new virus are the latent cells Someone with HIV who takes a few doses of inhibitors and stops might be fine for a while, but eventually the latent cells in their bodies will become active and start making virus. Then they’ll get sick all over again. This life-long cycle of inhibitors is the only way to keep HIV in check until scientists can find a way to kill latent cells before they ever start making HIV. With a combination of inhibitors and drugs that target latent cells, we’ll have a cure.",
"HIV is a virus that damages a person's immune system and kills their white blood cells, allowing simple diseases or infections to become deadly. AIDS is a syndrome diagnosed when you have a low enough white blood cell count. Viruses like HIV aren't living beings like bacteria, and don't need special conditions and \"food\" to live, they are just packets of DNA that inject themselves into human cells and try to reproduce and sometimes cause problems. Because they are so simple, viruses can evolve and mutate very fast meaning drugs which can kill them stop working very fast. Since viruses lock onto cells it is currently impossible to hurt the viruses without damaging the host's body as well. That goes for any virus, although some are more dangerous than others. Medicines today only control the symptoms the virus causes, and cannot permanently kill the virus itself. Some viruses have vaccines that train your body to fight the virus so that if you were to become infected, your body would instantly know how to kill the virus before it can spread and mutate.",
"I'm an HIV vaccine researcher. /u/wittymcusername does a great job of identifying some of the challenges involved with HIV cure research. But that's only part of the picture. Here is every reason I can think of. **Viral Escape.** As described by /u/wittymcusername, HIV has a high mutation rate. In addition to changing the proteins that make up the individual virions, the virus has a coat of sugar-like molecules called glycans that essentially shield the virus protein from being targetted. Every time your body comes up with some way to shut the virus down, some of the HIV in your body reacts by changing these glycans. This is like if the Police say they are looking for a suspect wearing a bunny mask, then the criminals take off their bunny masks and instead dawn tiger masks. **Immune Targetting.** HIV is especially problematic because unlike most infections, it specifically targets immune cells. Imagine an organized crime ring: You have enforcing agents who go around gathering \"protection\" money from businesses, drug dealers, etc... but also crooked cops who have been convinced to help the criminals instead of the people. HIV effectively turns good cops bad by making them stop working well. This is especially problematic because the cells HIV infects are responsible for major immune decisions, including the \"internal affairs\" units. Essentially, the only way to get rid of these bad agents is to eliminate all of them and replenish from an uncorrupted source. So far, we've accomplished this once, which I'll mention how in a little bit. **Viral Reservoirs** are the hardest modern challenge facing current cure efforts. Viral escape, mentioned earlier, creates entirely new infectious HIV. But it also creates non-replicative HIV sleeper cells: some mutant HIV viruses insert their genetic code into host cells in odd places. The cell doesn't seem to be infected until one day, it gets an atypical but normal signal and **BOOM!** it starts spewing out fresh HIV viruses. Because the cell is not making HIV proteins, it is nearly impossible to target... Thus it serves as a reservoir for restoring HIV should the active virus be eliminated in the future. This is the major focus of current cure research: It may sound scary, but the goal to figure out how to safely reactivate these reservoirs so that the secretly infected cells can be eliminated. It may be high risk as well, but the hope is that we can manage to eliminate it effectively. **We have cured one person.** Timothy Ray Brown, aka *The Berlin Patient* is considered HIV negative and takes no anti-HIV drugs anymore because he is believed to be cured of HIV. This happened because he had cancer. Brown recieved Chemo, Radiation, and a Bone Marrow transplant in addition to HIV treatment. When he finished having his cancer treated and cured, he was tested for HIV and found to be negative for it. For the Police/Criminal metaphor, this would be like killing all the Police seargeants, burning the Police Academy to the ground, and building a new academy. Brown has to take medication to keep his transplant healthy, but HIV medication isn't part of it.",
"There's a lot of great answers on why, and a lot of them refer to its high mutation rate. This is a factor in finding medicines that work against it. The reason we can't really cure it is because it becomes a part of you once it infects you. First to understand how the virus works: URL_2 To talk you through the video if you do not understand it: first there is a detailed description of how the HIV virus particle enters the cell. This is not extremely relevant but it is interesting. Then it goes on about how the RNA (the genetic information of the HIV virion) becomes DNA (which is the 'format' of genetic information our cells use in their nucleus). A lot of errors are made in this step, which is why the virus is constantly evolving. Next what you see is that the Virus' genetic information becomes a part of our own genome, i.e. it becomes an unseperable part of the cell it has infected. Once it is in there, it is not going to get removed again. It stays there for the rest of the cell's lifetime. It then can start producing new virus particles. It doesn't necessarily do this directly. It could do so immediately, or it might wait a few months or even years before it starts this process. This means that you may be infected without any way of knowing (but during this time you are probably not going to be able to infect other people, unless there are other infected cells which are producing HIV particles of course). The only way to completely cure a person from HIV is to either kill all the cells that have been infected, or remove the genetic material from those cells. The former is really difficult, because you will just kill the entire immune system of the infected person, and there is no way of being sure that there are no infected cells left, so it is not a realistic option. The latter is really also impossible at the moment. First of all, even if we could, we would not be allowed to, since we are not allowed to genetically modify people. Secondly, we don't have the means of transporting the proteins capable of doing so into the target cells (and the target cells only). Some people are looking towards CRISPR/CAS9 as a possible solution to this problem, but perhaps it might be more realistic at a current stage to look for people who are immune to HIV because of a certain mutation (although there is no way of telling how soon the virus will then evolve to be able to infect those people as well). Some more material for understanding HIV that is really easy to understand: URL_1 URL_0 Disclaimer: I am not a specialist in this field, I'm just a humble biology student, so anyone who knows better, please feel free to correct me.",
"Well the easy answer without too much complex terms is that HIV is a virus, which means it can very easily change the properties of it's shell. So that would be like putting on a disguise so that the white blood cells can't detect it, and doesn't know how to combat it. And the other reason is that it directly attacks the white blood cells so the body can't even fight back if it wanted, this is AIDS part which is the autoimmune deficiency syndrome, so not only the body cannot attack the HIV but also any other disease which is worst part",
"Wow! Can't believe this is still going. It's going to take me a while to read through all these posts but a massive thanks to everyone for posting, even the more controversial posts.",
"There are a few reasons. 1. HIV is a *retrovirus*. Retroviruses have a single strand of RNA instead of double-helix DNA, like we have. RNA is less stable than DNA and easier to break, which means that retroviruses mutate and adapt very quickly. Even if you developed a drug that could cure it, a new strain would soon appear that is immune to your drug. Even vaccines only help against the current strain, and they only work if you get them before being infected. Other retroviruses include the cold and the flu, which don't have proper cures either - of course, these illnesses are less serious than HIV, because a healthy immune system can fight them off without a need for drugs (it can do this because the immune system, like the virus itself, is capable of adapting quickly basically by *trying everything* and \"seeing what sticks\" - unlike drugs, which must be developed and tested by humans, who are much slower). Which brings us to the second point... 2. HIV targets the immune system itself. Almost every drug we have is only there to give the body's immune system an \"edge\" in the fight; exterminating every last virus in the body is pretty much impossible - we rely on the immune system to clean up the survivors. Unfortunately, once HIV gets a foothold in the body the immune system can't fight it effectively, because white blood cells are the cells that the virus *targets* to reproduce. So to really cure HIV, you'd need to kill *every single virus*. Cancer has a similar issue (except in cancer's case, the problem is that the body doesn't recognize it as dangerous, so unless you kill every single cell it will grow back).",
"HIV does not just copy itself cells, it inserts itself into their DNA. For those cells it succesfully infects, it becomes a part of who you are. Medications can stop it from growing, and help you live a long life, but they can never take it out of your DNA. If you stop taking your pills, the virus will come back. Not only that, but when HIV mutates itself faster than almost any organism we know. This allows it to quickly develop resistance to drugs, unless you are on so many drugs at the same time that the virus is unlikely to mutate resistance to all of them at once. While some scientists are working on a way to cut the HIV out of people's DNA, we do technically have a cure, but it is very expensive and dangerous. You have to kill all your white blood cells, where HIV hides, then replace them with cells from someone who can't be infected with HIV.",
"To all those believing we don't invest in finding cures because it's more profitable to treat a patient for life: Look at Gilead. They created a CURE for hepatitis C recently. It's 99% effective with minimal side effects. They made over $12 billion in a single year curing people. The older medicines that weren't as effective were withdrawn from the market. There's definitely money in a cure. They are just really difficult to make. Also, we've only known about HIV/AIDS since the 80s. To have the medicines we have today that are so effective in such a relatively short amount of time is nothing short of amazing.",
"So normal cells have an error checking mechanism to keep error rates at roughly one in a trillion. HIV has an enzyme called reverse transcriptase. Basically, it makes DNA from RNA, and when the virus is inside a cell, it becomes a part of its DNA. Now the virus doesn't have any error checking of any kind. So it goes through the replication process unchecked, and if the virus makes any sort or errors or mistakes, it just rolls with it. It does this at such a rapid pace, that it can never stay stable enough to develop a cure for it. So to quote Q from Skyfall, \"It's like solving a Rubik's Cube that's fighting back\"."
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776otm | How did people book plane tickets before the internet and phones? | Repost | explainlikeimfive | {
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"Phones were invented before planes were, so by the time commercial plane traffic was a thing, telephones had already proliferated. There were also things called Travel Agencies. They're still around, but not used as they much as they used to be. You'd call them, tell them where you wanted to go and when, and they'd make all the arrangements for you."
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779z8k | Why is it that Nagasaki/Hiroshima were safe weeks after the explosion but Chernobyl won't be for thousands of years? | Repost | explainlikeimfive | {
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"The bombs had orders of magnitude less radioactive material, and they were detonated in the air, thus spreading the material wide and largely into the wind. As a result, the region recovered quickly as the radiation was dispersed. In contrast, Chernobyl had significantly more radioactive material and melted, combining it with steel and dirt, resulting in a sludge of very highly radioactive material. It solidified into the infamous \"elephant's foot\" that is so radioactive that people can't be in the same room as it without high risk.",
"Hiroshima was an air burst of 140 lbs of U-235 in a gun-type arrangement. The weapon was detonated at ~1,800' above the ground and this greatly reduced the amount of neutron activation in fallout debris lifted in the updraft that you would get from a ground burst. This means this small amount of radioactive material is the principle component spread across a ~4 mile radius. Approximately 2% of the uranium was fissioned in the detonation. Uranium has a long half life, over 4 billion years. This means it's pretty stable, and the rate of decay is actually pretty slow. Depleted uranium, U-238, is used as an anti-tank projectile and handled with bare hands. Thorium can be bought in any quantity from any welding supplier. The neutron activated products and some of the radioactive byproducts from radioactive decay have a much shorter half life, so they're hot, they're active, they're dangerous because they're dosing quite a bit over a short time, and the material spread so thin, it cools off relatively quickly. Chernobyl reactor 4 had 210 tons of radioactive fuel in it, and it was emitting fire, steam, and gasses for over a week. It contaminated the ground water, which spread into the surrounding environment, and it kept on leaking. Chernobyl released ~400x radioactive material into the atmosphere than Hiroshima, and a number of radioactive products not seen in significant quantities from the nuclear weapon. With Chernobyl, it's the amount of material in the environment, despite their longer half-lives, at this point, that makes the whole area so dangerous. > Why can't it be cleaned? How? It's not like there is visible radioactive bits that can be swept up. Think atomic sized dust. You would have to strip the whole landscape bare, like a strip mine. You would have to follow all the contaminated ground water paths. You would have to ensure the material removed doesn't leave containment and that the cleaned area doesn't itself get re-contaminated. The logistics are simply unfathomable."
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77aaik | Why does India have so many people? | Repost | explainlikeimfive | {
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"The poorer part of India is against birth control, breeds until they have enough men to sustain the family, because once you're old you're supported by your children, and other cultural reasons that promote large families.",
"In addition to the history of ideal conditions for population growth, appears to me like a cultural issue as well. It's a culture in which men are controlling and women have no say in family planning. This is why in developed nations where gender equality is more pronounced and women have more autonomy, the rates of births will decrease.",
"I am an Indian and will try to explain from my understanding of our history. 1.Indians totally value family above all else. So the concept of an only child is pretty rare. 2.Historically India was many many kingdoms constantly at war with each other. It was not till 200 years back that wars reduced. So it was common for couples to have many children as many would die. 3.Improved health care is definitely a contributor. 4.Lack of education. Poorer classes still believe their sons would be able to support them."
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77ako0 | How do courtroom stenographers record everything that is said accurately? | Repost | explainlikeimfive | {
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"Yes, I do this for a living (transcription, not stenography)! I can answer this question! xD Okay, so you've got two types transcription: stenography and regular keyboard transcription. Stenographers essentially use a phonetic keyboard. They can type an entire word by simultaneously pressing multiple keys on their board, much like a pianist playing multiple notes to make a chord. Because each word only takes one press, it's very easy to keep up with the pace of someone's speech if you've been trained to use a stenotype. They're more frequently used in running trials and civil cases where the counsel for the parties needs a running transcript of the proceedings as soon as humanly possible. It takes a lot of training to become a stenographer and they're becoming increasingly more rare. The large bulk of transcripts (in Australia) are now performed by keyboard typists. When needed to do real-time transcription, they work in groups of two to three, on alternating blocks of audio that they can pause and rewind.",
"They use a shorthand keyboard called a stenotype. It's missing some letters like C because it can be replaced with an S or a K, so you don't have to use as many letters."
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77cmru | How the hell do speakers create sound? How is something that vibrates able to recreate entire orchestras and audiences clapping? | Repost | explainlikeimfive | {
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"First, remember that all sound is just vibrations in the air that hit our ears. They're very specific vibrations, but vibrations nonetheless. Speakers work VIA magnets, specifically electromagnets interacting with traditional magnets. So when you run an electrical current through a coil of wire, you produce a magnetic field. This is the basis of electromagnets; Speakers work by having an electromagnet coil attached to a thin membrane, and then a little bit away having a static magnet. Electromagnets have alternating polarity of the magnets, while static magnets have, well, a static north pole and south pole. So as the current flows through the wire, it alternates the north and south poles, creating attraction and repulsion forces *very* quickly. The signal changes based on the sound that is trying to be played through, but here's the genius: a microphone and a speaker are basically the same thing. Much like running an electrical speaker through a coil of wire will produce a magnetic field, moving coils of wire around a magnetic field will produce an electrical charge. So a microphone picks up sound waves through the thin membrane, which moves a coil of wire around a magnet, and sends that electrical signal to a computer (or something, but these days it's a computer) that can store the electrical data that is sent out. Then when the recording is played back, it sends that electrical signal out to the speakers, which creates a magnetic field which moves the thin membrane to push air in proper sound waves."
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77dzjs | How does Einstein's theory of relativity work? | Repost | explainlikeimfive | {
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"Here is how I think about it. We have two conflicting rules: 1) Nothing can move faster than the speed of light; and 2) For every action, there is an equal and opposite reaction (which mathematically is expressed as Force = Mass X Acceleration) If you are traveling in a spaceship going just under the speed of light, say 0.9999999999999% this doesn't break rule 1 or 2. No problem. But then say you throw a sofa out of the back of your spaceship. Rule 2 says you should speed up. But rule 1 says you can't. So the universe cheats. Force = Mass X Acceleration has, as its basic units, Force, Mass, Distance, Time. To preserve Rule 1, the universe starts to mess with Mass, and Time. It slows time down in fact, and the faster you are going, the slower time goes. In fact, when you really are going at 0.9999999999999% the speed of light, your rocket engine is really a time machine. You turn on your rocket and instead of going faster, you make time slow down more and more and more from your perspective. You, personally, could travel across the galaxy in a few weeks if you just had a conventional rocket big enough. On earth thousands of years would pass, but for you, it would be virtually no time at all."
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77fx9w | The Iran-Contra Affair... What exactly was it? | I've done a bit of research into it, but for whatever reason I'm having trouble understanding EXACTLY what happened, how the Reagan Administration was involved, how the CIA was involved, and what the consequences of it were. Could someone break it down for me? What happened with Iran, what happened in Nicaragua? Thanks! | Repost | explainlikeimfive | {
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"The US was not allowed to trade with Iran (because of the hostage crisis in 1979 when they deposed The Shah, who was... let's say \"friendly\" to the US). Reagan also wanted to support Nicaraguan rebels called The Contras against the socialist government that was there. But he couldn't get the money from Congress to do it. Iran was in the middle of a war with Iraq (whom the US sold weapons to as well), so the US sold them conventional weapons to get money to give to the right-wing Contras. When this was found out, Oliver North was thrown under the bus, and Reagan (dozens of times) did not remember what happened. > What happened with Iran, They got a lot of guns from the US government > what happened in Nicaragua? The Contras weren't very effective. The government in Nicaragua sued the United States in the International Court of Justice but didn't win because they couldn't prove the US directed the Contras, just gave them money and propaganda. However, evidence did come out that the US was condoning atrocities that the Contras were committing."
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77i5gl | Why do beverages taste different in cans than they do in plastic or glass bottles? | Repost | explainlikeimfive | {
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"Probably not what you're looking for, but I know that plastic bottles don't hold carbonation as well because of the way the molecules bond together compared to glass or aluminum cans."
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77lnt9 | How stock trading works/worked? I've only seen it in movies so I'm wondering why these people were always just screaming and waving pieces of paper around and call it a job. | Repost | explainlikeimfive | {
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"The angered mob was buying and selling shares of stock to one another. The setting for these trades is called the trading floor. The loud shouting was to inform anyone your interest of selling or buying a quantity of stock at a price. Once you find someone to make the trade with, you each fill out a trading slip and the transaction is confirmed. Now, more popularly, the asking and bidding on shares is performed via computers.",
"It's not like that anymore, but it used to be pretty much what it looks like. Guy 1: \"I'm selling $STOCK for $MONEY\" Guy 2: \"I'll buy 1,000 $STOCK for $MONEY!\" Guy 1: \"Sold!\" Remember, the movie scenes are almost always pegged on some crazy fiscal meltdown. It didn't look that chaotic most of the time. These days it's all digital. Sellers post their prices, and buyers try to buy only to get screwed out of a nickel by unscrupulous flash traders. Heh.",
"It's almost all digital nowadays. There are people offering to buy stocks at a certain price and there are people offering to sell stocks at a certain price. A computer matches them and executes the transaction.",
"In very very very basic terms it's the super dilution of ownership of a company. Stock is basically, well the stake of a company, broken up into tiny tiny pieces and put on the public market. Usually a board of directors own enough shares to control the company while the shares that go out on the market are called publicly traded shares. Say for example, you are a cannibal recipe website called Facecook and you as a private company have grown in popularity. You now need an injection of money to go to the next level and you don't want some huge investment firm controlling so much they could replace you. You break up your company's ownership into tiny shares, keep a majority for yourself, pass on some smaller amounts to your board of directors and your employees and the rest goes on the market. You set a reasonable valuation for it on the day it goes public, called the IPO or initial public offering. People all want a piece of the action, because they know if you do well, the stock value goes up (including that face cook stock you bought). Stock price goes up as demand goes up, or if there's rumors of something awesome you're doing. But in all honesty, most people on the public market are there as hawkers at a bazaar. Their aim is to buy at low prices and sell at high prices. The amount they get to own of your company is so little, they have little to no say in what your company does as an individual. But as a collective, every time there's Frenzy to buy, they drive your stock price up and inject capital into your company. EDIT (here's the part you were looking for): For individuals who play the game at the frenzied bazaar full time, they're all trying to hit gold. Have those few super massive successful trades that can make them millionaires in a matter of minutes. With thousands of people trading non stop around the world, values fluctuate like crazy. And provided you have the right mix and the right access to buy and sell stocks from the right company, you can make a killing (and lose it). When they scream sell sell sell, they want people to dump the stock because there's reason to believe it will drop. Once it bottoms out. They'll buy it again and sell it once it rises. It's like a manifestation of what nature is - an adrenaline fuelled chaotic race for survival over limited resources where wit, cunning and luck can all work in your favour or you can lose out despite 'doing everything right'",
"Nowadays it's almost entirely electronic. Traders submit orders into the exchange that are like \"I want to buy 100 shares of XYZ at $30,\" and as soon as someone is willing to sell at that price, the exchange informs both parties that the trade has occurred. The exchange will also list what the current highest \"bid\" and lowest \"ask\" are, so you'd see that someone is currently willing to buy 100 shares of XYZ for $30 and someone else is willing to sell 500 shares for $30.01. You can also submit a \"market order\" like \"sell 1000 shares to whomever will give me the best price,\" which in the above example might cause you to sell 100 shares to the guy bidding $30, then another 400 to some other guy bidding $29.99, and the last 500 to someone else bidding $29.98. The exchange will automatically figure out who owes what and handle the transactions. However, this was all much harder before computers. Instead of submitting your order automatically, you'd need to have someone on the floor of the exchange yelling about how much you wanted to buy/sell and the price. When you tried to buy stock for your personal account, your bank would then contact their floor trader to buy that stock for you. The pieces of paper were for writing down what trades that trader personally had done. When you'd see those people in movies, it'd be during major moves in the price, which would cause significant activity in the area and increase the general level of chaos. You might think \"why wouldn't they lie about what happened?\" They could do that, but failing to follow through with a trade just because it ended up bad for you would destroy your reputation, and the rest of the traders would know and you'd never get trades again."
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77m0ob | How does Silicone hold information. basically giving us computers | Repost | explainlikeimfive | {
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"It is silicon. [Measured by mass, silicon makes up 27.7% of the Earth's crust]( URL_0 ) Silicon is next to aluminum It is a member of group 14 in the periodic table, along with carbon above it and germanium, tin, and lead below. It is a semiconductor, neither a good conductor like aluminum or an insulator. As such it can be loaded with electrons, or have electrons removed leaving 'gaps, or spaces for electrons. This means it can be used as a 'gate' to regulate the flow of electrons, or current. Farmers know gates are very useful. So do electrical engineers, the ability to start and stop a current flow makes transistors, printed circuits, chips, and diodes possible."
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77mts0 | If bones can heal itself, Why cant our teeth do the same? | Repost | explainlikeimfive | {
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"text": [
"Contrary to semi-popular belief, teeth are not bones. As a result, they do not feature the same regenerative abilities as bones."
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77n1tu | What is it that our bodies do when we sleep? Why do we need it, what is "replenished" etc? | Repost | explainlikeimfive | {
"a_id": [
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"We don't really have a definite answer, some say it's important in the conversion of short term to long term memory, that when you sleep your mind basically gets a chance to\"De-fragment\" all of the information you took in that day. Others say it's necessary in order to give our bodies time to heal and recover, but our bodies are constantly healing and generating new tissue, while sleep may make the process easier it's not as if our bodies only heal while we're asleep. Some scientists believe it's something living organisms simply adapted to do as a way to conserve energy, we can't hunt or gather food when our vision at night is poor, so it would make sense to go dormant as a survival mechanism in order to not waste energy. It could be one of these, it could all of them, or something we don't even know, but at this point the jury is still out. Sleep is necessary to us, but why we and many living organism developed this nessecity is still unknown. *Edit some typos."
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77qsf0 | Is there an 'fps' for sound? | Repost | explainlikeimfive | {
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"text": [
"It's called the sample rate. Standard for CD audio is 44,100 samples per second. Unlike FPS it is usually fixed.",
"Yes. CDs use 44 & #8239;100 samples per second. More modern formats are moving to 48 & #8239;000 and some audiophile content uses 96 & #8239;000 or even 192 & #8239;000. Human hearing goes up to about 20 & #8239;000 & #8239;Hz and theory says you need at least double that to represent the waveform (because each cycle involves a wave going up and then down, so you need to capture both peaks). On the lower end of the quality scale, phones use 8 & #8239;000 samples per second, because this is enough to carry the human voice. Unlike video, where you need a whole frame as a \"sample\", sound needs only a single number per channel, i.e., 1 number for mono, 2 for stereo, etc. Each number represents the height of the sound wave at an instant in time."
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77rysi | How is binaural audio made and how does it work? | Repost | explainlikeimfive | {
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"text": [
"Imagine you held a seashell up to your ear, and you hear it change the sound around you and make it sound like white noise. This is due to it's shape and reflectivity. If you were to put a microphone inside the shell, record the sound, and then play it back on a headphone, you would hear the same effect as if you had a shell up to your ear, because you're using the shell as a kind of audio filter, and recording the result. When it's played back, you hear the filtered sound which your brain interprets as a seashell next to your ear. HRTF or Head Related Transfer Function is an examination of perceptual cues we use in order to tell which direction a sound is coming from. Because of the shape of the exterior ear lobe, and the ear canal, the timbre or quality of a sound changes depending upon the direction it is coming from. This affects not just how loud it is, and which ear it is loudest in, but also if it's clear or muffled, and the delay between when one ear hears it first, and then the other. The brain uses all of these cues in order to understand where a sound is coming from. There have been software technologies that attempt to digitally modify sounds in a stereo headset, in order to provide these directional cues, but binaural audio takes this a step further. Actual ears are used, and a microphone is placed deep inside the ear canal inside of a dummy head, with prosthetic ears. The dummy head adds to the realism by reflecting sounds off of the face and side of the head much like skin, as well as the shape of the artificial ear encoding the directional cues in a very accurate way. When you play back the audio using headphones, your ears are hearing the original sound, modified by the shape of the dummy ear. And since headphones are as direct a way to hear sound as we can get, they act like binoculars for our ears, blocking out external sounds, and giving a very clear audio image, of the recorded binaural audio, and you hear it as 3 dimensional.",
"ELI5 answer: it's a way of trying to capture exactly what a person would hear in a particular position, by installing microphones inside a dummy head where your ears would be. If done properly to a high fidelity, and you listen to the results with good headphones, it should recreate the 3D experience as if you were there. Pearl Jam recorded an album - *Binaural* - that use the technique on several slower tracks, including [Nothing As It Seems] ( URL_0 )."
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77shpy | What happens on a molecular level when you cut or shred something? | Repost | explainlikeimfive | {
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"text": [
"You are not breaking apart molecules. You are however breaking the bonds between the molecules",
"You sheer the structure. Think of it like tearing apart a lego sculpture. The individual blocks (molecules) are still intact, but you have broken where they lock into other ones."
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77tg4e | How do vinyls, specifically their grooves, work? | Repost | explainlikeimfive | {
"a_id": [
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"text": [
"There is only one long groove on a record. It begins around the outer circumference of the record and spirals in towards the label. As you play a side, you can watch the needle move closer and closer to the center over the 15 minutes-or-so it takes for the side to be played."
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7837j0 | How important is the language in humans' thinking process? How were humans able to think before the existence of any language? | Repost | explainlikeimfive | {
"a_id": [
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"text": [
"Language is definitely not required for the human thinking process, though the task of explaining your thoughts using a language can help. Computer programmers often use a technique called \"rubber ducking\", where one programmer explains his or her problem to another programmer, while the second programmer does nothing except nod their head and say \"uh huh\" over and over again. This process of forcing thought to language helps organise the thought process, and helps with problem solving."
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786cy8 | why is it that when all other species show their teeth it is an act of aggression but when humans do it, it's a friendly gesture? | Repost | explainlikeimfive | {
"a_id": [
"dorfqdo",
"dorg0ol"
],
"text": [
"The smile evolved in primates approximately 30 million years ago, humans got it from there. Evolutionary biologist think it evolved from a submission response. IE it used to be a I submit to you, co-opted to an I approve/am happy. What does this have to do with teeth? The submission response was in turn an adaptation of a fear response. I am scared of you, so I submit to you. Many fear responses involve the bearing of weapons or making yourself seem bigger, see cat's arching backs or hissing. TL:DR: used to be fear look - > submission look - > approval look.",
"Here is a good [Scientific American article on that very subject]( URL_0 ). It's interesting to note that amongst babies showing teeth is more a sign of fright than it is of friendliness/friendship. That provides a clue and is accordance with the saying \"ontogeny recapitulates phylogeny\" (i.e. the development of an organism tells you about its evolutionary history). Frank McAndrew, a facial expression researcher has this to say: > \"Baring one's teeth is not always a threat. In primates, showing the teeth, especially teeth held together, is almost always a sign of submission. The human smile probably has evolved from that. > \"In the primate threat, the lips are curled back and the teeth are apart--you are ready to bite. But if the teeth are pressed together and the lips are relaxed, then clearly you are not prepared to do any damage. These displays are combined with other facial features, such as what you do with your eyes, to express a whole range of feelings. In a lot of human smiling, it is something you do in public, but it does not reflect true 'friendly' feelings--think of politicians smiling for photographers. He also points out that it is so deeply ingrained in us that even congenitally blind people smile in the same way in response to the same stimulus as sighted people. There are a few links to further reading on the subject at the conclusion of the article."
],
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9,
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"https://www.scientificamerican.com/article/how-did-the-smile-become-a-friendly-gesture-in-humans/"
]
]
} | [
"url"
] | [
"url"
] |
|
788r0x | Why do India and China have such massive populations in comparison to the rest of the world? | Repost | explainlikeimfive | {
"a_id": [
"dorvsn7"
],
"text": [
"I'm almost certain this has been answered before, but it's largely due to geography. India and China both have exceptionally fertile river valleys capable of supporting large populations with pre-industrial technology. Even before the world population started exploding during the past two centuries, they were the two largest and richest civilizations on Earth - for example, in the early days of India being a part of the British Empire, it's 'GDP' was over half the productivity of the entire British Empire (including the British Isles themselves)."
],
"score": [
6
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
78ey8c | What do the police do with the money after a big drug bust? | Repost | explainlikeimfive | {
"a_id": [
"dot9q0w",
"dotauhd"
],
"text": [
"In the USA, the money is essentially charged with suspected illegal activity and seized to be used as law enforcement sees fit, unless the owner of the money can prove that the money was not used in any illegal activity. This process is called [civil forfeiture]( URL_0 ). Note that this process is separate from the owner being charged.",
"And is there a quota for bust money budget? Like do they increase #of speed ticket quota if there is a shortage of bust money this quarter? Edit. Now I want to see the police financial statements. Are these public?"
],
"score": [
35,
3
],
"text_urls": [
[
"https://en.wikipedia.org/wiki/Civil_forfeiture_in_the_United_States"
],
[]
]
} | [
"url"
] | [
"url"
] |
|
78j9pj | Why does the name "Germany" in English sound so much different than the actual name of Deutschland? | Repost | explainlikeimfive | {
"a_id": [
"dou94z6"
],
"text": [
"\"Germany\" as a place name (from the Latin Germania, named for the \"Germani\" people) existed long, long before \"Deutchland\". That part of Europe has gone through a lot of political changes throughout history. It's almost more appropriate to think of \"Deutschland\" as the nation currently in the area called \"Germany\". 200+ years ago \"Germany\" was the home to the Holy Roman Empire. We still called it the region \"Germany\"."
],
"score": [
8
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
78olk6 | What's an ion thruster? How does it work? | Repost | explainlikeimfive | {
"a_id": [
"dovened",
"dovncfa"
],
"text": [
"It is a propulsion device that uses a combination of a gas plus some sort of electric field to accelerate the gas and shoot it out the back of the thruster assembly. The gas, usually xenon or argon, is given a negative charge. electric charge by passing it over an electric filament. The gas is then sent to the thrust chamber where they are accelerated by a combination of magnets and electrically charged plates. That acceleration combined with the ejection of the ions out the back gives the assembly its thrust.",
"In space travel there's a problem often referred to as \"the tyranny of the rocket equation.\" You have to use fuel to accelerate, but the more fuel you bring the more fuel it takes to accelerate. To go incrementally faster you need exponentially more fuel. To maximize the \"fuel efficiency\" of a space propulsion system you want the highest possible exhaust velocity. This means that you get more impulse (force × time) for a given amount of fuel. Rockets are often described in terms of \"Specific impulse,\" or Isp, which quantifies this value. It's in units of \"seconds.\" In a chemical rocket the energy for accelerating the propellant comes from the propellant itself. This means that there's a limit on how fast the exhaust can ever be: even if you convert 100% of the chemical energy of the fuel into thermal energy of the exhaust and perfectly handle the nozzle there's a max exhaust velocity you'll achieve. In an ion thruster you do away with the idea that the propellant should be an energy source, too. You harvest energy from a solar panel (or other source, but only solar panels are attractive for their weight), then you use strong electric fields to massively accelerate tiny quantities of fuel to speeds that can start to be non-trivial fractions of the speed of light. These thrusters typically have tiny amounts of thrust, but they use fuel incredibly slowly. The general concept for using an ion thruster is that it will provide thrust over weeks or months, ultimately reaching speeds that are unfeasible for a chemical rocket. While chemical rockets are often doing well to have Isp ratings in the 400-500s range, ion thrusters can sometimes reach the 10,000s+ range."
],
"score": [
10,
7
],
"text_urls": [
[],
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} | [
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] | [
"url"
] |
|
78pog1 | In the search for extraterrestrial life, why do we assume water must exist on a planet for life to exist? Why can't there be organisms with different biologies that survive on elements other than hydrogen and oxygen? | Repost | explainlikeimfive | {
"a_id": [
"dovnpad",
"dovo13o"
],
"text": [
"Because our only point of reference is carbon-based lifeforms that rely on water. Of course there's the potential for other forms of life that are not carbon based and/or don't live in enviornments with water, but how would you even begin to look for something you can't define since you have no point of reference? The universe is mind-bogglingly large, you need to narrow down your search somehow.",
"because we don't have any knowledge of those types of life. we would have no idea how they work or how to look for them. we are very familiar with carbon based life, so that's what we're looking for. sci fi shows have made up silicon based life forms but they're just made up. we have no idea if they would exist or not."
],
"score": [
4,
3
],
"text_urls": [
[],
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]
} | [
"url"
] | [
"url"
] |
|
78pprh | How do TV programmes like The Simpsons make money from being aired? | Repost | explainlikeimfive | {
"a_id": [
"dovnvip"
],
"text": [
"Fox pays the creators of The Simpsons to create 1 or more seasons (depending on the contract). They use this money to pay the writers, animators, voice actors, creative staff, and everyone else involved with making the actual show. Fox is paying the creators because a certain number of viewers will watch the show which means that companies are paying Fox to air commercials during the time slot The Simpsons is airing. The more viewers, the more ad revenue can be asked for. Depending on the contract, Fox might also get a cut of any DVD/digital, merchandise sales."
],
"score": [
4
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
78qgud | How does hand soap kill/destroy/remove bacteria on your hands? | Repost | explainlikeimfive | {
"a_id": [
"dovv0e7"
],
"text": [
"A lot of it is simply mechanical removal. Soap molecules have one end that is attracted to water and one end that is attracted to oil. If bacteria get coated in these molecules, then water will rinse them off more easily (with a good scubbing). Soap can also kill bacteria directly, because their membranes are also made of molecules with one water-loving end and one oil-loving end. This allows soap molecules to interact with these membranes, and this interaction can punch holes in the bacterial surface."
],
"score": [
5
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
78u9u2 | Difference between lobbying and bribing? | Repost | explainlikeimfive | {
"a_id": [
"dowqk4f",
"dowqdfr",
"dowrelt"
],
"text": [
"There are a few main differences: * The first is transparency. Lobbying is recorded, and generally has to be accounted for. A bribe would obviously be unrecorded and under the table. By keeping track of donations via lobbyists, it makes it harder to make really oblique payments. Most political officials are also restricted from receiving certain kinds of gifts or services. * The second is the level on which it takes place. Bribery is generally done on a one-to-one level. A single person offers money to a single official for a specifically desired outcome. Lobbying is a bit more general, a donation to a larger campaign effort or party coalition, and usually with a more broad goal of leaning things a certain way, but not directly paying for a specific returned outcome. * Additionally, unlike how a bribe is generally considered, there's no true obligation on the part of a government official to act a certain way. There's no recourse or threat that can be done by a lobbying group if the official decides to not vote along the lines they wanted, regardless of donation. They can simply choose not to donate to that person again. * Laws also put a (theoretical) limit on how much can be donated from one person or group at one time, and all that money is tracked and logged by oversight committees.",
"Not much I'm afraid. Their pretty much the same thing with bribery being illegal but lobbying legal. Also, lobbying usually includes a bunch of parties but bribing only 2",
"There is a huge misconception that lobbying is just bribery. In reality lobbying is much broader. If you ring up your representative, you are lobbying. If you present a report to a representative, you are lobbying. Basically any contact with MP's/Senators (or your local equivalent) for political purposes constitutes lobbying. The democratic process *relies* on lobbying."
],
"score": [
8,
5,
3
],
"text_urls": [
[],
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
78x7fp | Why is it after an activity like running, things like music sound like they are going in slow motion? | Repost | explainlikeimfive | {
"a_id": [
"doxd4ww"
],
"text": [
"Never experienced that. Perhaps you should see a doctor?"
],
"score": [
6
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
78zijj | the first law of thermodynamics | Repost | explainlikeimfive | {
"a_id": [
"doxwt0d",
"doxwvuh"
],
"text": [
"In an isolated system, energy can be changed to other forms but it cannot be created or destroyed. This law is true for all isolated systems and non-nuclear reactions.",
"The 1st Law of Thermodynamics states that in thermodynamic systems energy must be conserved. You can move energy around, you can change the form of the energy, but you can't create or destroy energy. Put in simple terms \"There's no such thing as a free lunch.\" Everything costs something."
],
"score": [
11,
3
],
"text_urls": [
[],
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]
} | [
"url"
] | [
"url"
] |
|
790438 | What purpose do eggs serve in baking? It seems as if we put eggs in almost everything we bake, but what do eggs do chemically that is crucial for the baking process? | Repost | explainlikeimfive | {
"a_id": [
"doy2rue"
],
"text": [
"As you probably already know, oil and water don't mix. Well, this can be a problem when you're cooking, because you might have some ingredients that are water-based, and other ingredients that are fat (or oil) based. So, how do we mix them? We need an intermediary - something that can combine the two of them. Egg yolk contains lecithin which is great for this purpose - it's a molecule that attracts water molecules on one side and oil molecules on the other. Without this, lots of foods would separate, and you don't want that!"
],
"score": [
8
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
7920lf | Why does the urge to pee increase so much when you are approaching the front door? | Repost | explainlikeimfive | {
"a_id": [
"doyi3qf"
],
"text": [
"Pavlov call. Your body predicts as task and prepares for it. Same with ordering food. You will create lots of saliva while ordering food because your body knows it is going to take food so more saliva will help break down the food."
],
"score": [
12
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
793t1b | How are cheat codes discovered in video games? | Repost | explainlikeimfive | {
"a_id": [
"doyvyi7"
],
"text": [
"The vast majority of them are released by the developers themselves. A lot of the early cheat codes were simply stated in strategy guides or gaming magazines, so intentionally distributed for people. Another group of them come from developers but not officially, they just leak over time since many coders, devs and testers were aware of them eventually they share that information. Sometimes the 'cheat codes' are part of a debugging system that just never gets removed when the game ships. Then another portion are discovered in the code itself. Eventually someone will crack open the game code, look around and find extra areas or extra codes and commands that will do various things. And some of it is password systems like in Old NES games where people kind of crack the code and figure out entering certain codes will force the game into a specific state, Metroid in particular has a big list of these where the save game can give you unlimited missles, invincibility etc... But very few of these things are discovered by just hitting random buttons to find them."
],
"score": [
4
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
7943xx | How does a mirage work? | Repost | explainlikeimfive | {
"a_id": [
"doyz0xs"
],
"text": [
"The example that's easiest to explain in simple terms are mirages in the desert, often mistaken for bodies of water. Mirages can occur elsewhere (e.g., long stretches of highway or at sea), but let's stick with just one place for simplicity's sake. One thing to keep in mind: mirages almost invariably occur in conditions involving bright, unclouded sunshine and relatively high temperatures. In terms of their *effect*, mirages are basically air-mirrors. Unlike regular mirrors, mirages function by \"refraction\" (i.e., *bending*) light rather than \"reflection\" (i.e., *bouncing* light), but the optical *effect* winds up being pretty similar in this case. What happens is that in the desert, the temperature in the few inches above the sand is *dramatically* hotter than the temperature even one foot up. As much as 30-40F. Light behaves differently in different media, yes? This is why lenses work: the transition from air to glass *bends* the light. Well, the *temperature* difference in the few inches of air immediately above the surface of the sand is enough to act like a lens, of sorts. Light comes down from the sky, is bent by that thin layer of hot air so that it comes *up* to meet your eye, *without* reflecting off the sand. So you're looking *down*, but the light you're seeing actually comes from *above*, and has not interacted with the surface of the sand at all. Because the eye expects bodies of water to reflect the sky above them, your brain interprets this *refraction*, caused by a thin layer of hot air, as if it were the result of *reflection* from a body of water. Mirages can create other sorts of images too. For example, you can see an inverted image of a ship near the horizon, or a mountain off in the distance, not just an apparent \"reflection\" of the sky. Same principle."
],
"score": [
3
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
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|
7944t3 | Before toothbrushes, how did humans clean their teeth? | Repost | explainlikeimfive | {
"a_id": [
"doz4311",
"doyydzv",
"doyyllf"
],
"text": [
"I think there is also a difference in diet that makes cleaning a little less important. We eat a lot of sugar that was not available historically.",
"Some didn't, some picked at their teeth with twigs and stuff, some would fray the end of a fibrous plant stalk and make a little brush, etc.",
"Basically by gnawing on twigs and roots and stuff. Muslims still have this tradition and will sometimes use a sewak. According to some of their legends they can earn favor with their gods by using a sawak before praying URL_0"
],
"score": [
15,
11,
6
],
"text_urls": [
[],
[],
[
"https://www.amazon.com/Sewak-Al-Falah-Traditional-Natural-Toothbrush/dp/B00F22IZY4"
]
]
} | [
"url"
] | [
"url"
] |
|
797s3z | How did last names come to existence? How are new last names made? | Repost | explainlikeimfive | {
"a_id": [
"doztuad"
],
"text": [
"Many were their professions. Smith, Baker, or my father who made our family name after his favorite duty. Dickinson"
],
"score": [
4
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
799f3a | Why if something spins very fast we see that it changes direction. | Repost | explainlikeimfive | {
"a_id": [
"dp06683"
],
"text": [
"That's actually an artefact of the *recording* process. Since we only capture a certain number of frames each second, if there's, for example, a clock face with the minute hand spinning around extremely fast, then if it's moving at *just under* once around every second, and we're recording at 60 frames per second, then every time the camera records the scene, the minute hand will be slightly *before* where it was the previous frame, since after the picture it spins all the way around again until just before its current position which is right when the camera is ready to take another picture. Imagine taking one photograph every second. If you are walking around in a circle, but are walking that circle in just under one second, then every time the photo is taken it'll be just before you reach the point you were in when the photo was last taken. If you put all of these photographs together one after the other, you'll *appear* to be moving backwards, because the parts where you walked all the way around are missing, and so when we watch an animation of those photographs, we assume you were just walking backwards and taking the photos more rapidly."
],
"score": [
8
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
79azcl | How are we able to drink liquid upside down? | Repost | explainlikeimfive | {
"a_id": [
"dp0i5ld"
],
"text": [
"Same reason astronauts can eat in space: Humans don't rely on gravity to consume things. We swallow with muscles."
],
"score": [
3
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
79fp90 | Why melting icebergs cause sea level to rise while ice cubes melting in water glass don't? | Repost | explainlikeimfive | {
"a_id": [
"dp1kz6m"
],
"text": [
"I may be wrong but I always thought these icebergs were, at least partially, out of water, on land. So the run off from the melting glacier/Berg goes into the water."
],
"score": [
3
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
79hmkp | How do activated carbon filters work? | Repost | explainlikeimfive | {
"a_id": [
"dp204ov",
"dp22br8",
"dp2c7ko",
"dp2ek8a"
],
"text": [
"Basically the carbon has tiny tiny pores that pull things out of water/air/etc via what's called the van der waals force. Different base materials (coconut, wood, animal bone) result in different size pores which are used in different applications depending on the medium and what you're trying to filter out.",
"The carbon used is created by heating some kind of organic material in an oxygen-free, low-pressure chamber. Apparently coconut husks wok well for this. The result of this is pyrolytic carbon. On a very small scale, the carbon consists of a spongy, randomized, lace-like network of carbon atoms. The material has an extremely high surface area. Large molecules such as volatile organic compounds (VOC's) tend to get trapped in all the tiny voids and crevices in the material, while small molecules like N2, O2, or H2O can fairly easily pass through it.",
"Insanely huge surface area, allowing it adsorb huge amounts (relative to the amount of carbon) of what have you",
"They are two reasons: - Very high ratio surface/volume -Due to incomplete burning process there are several different organic groups attached that can hold back different kinds of molecules, this with the non-specific forces allow activated carbon to filter a very large range of compounds."
],
"score": [
40,
10,
8,
3
],
"text_urls": [
[],
[],
[],
[]
]
} | [
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] | [
"url"
] |
|
79jokn | Why do ice cubes crackle when liquid is poured on them? | Repost | explainlikeimfive | {
"a_id": [
"dp2hlj7"
],
"text": [
"So most things expand when heated and retract when cooled. Because ice is already so cold, when you pour a liquid on ice, the surface that the liquid hits will instantly expand, and the rest of the ice doesn't have time to catch up. The top surface expands from heat and the rest of the ice remains cold and doesn't expand. Suddenly, boom, the ice cracks. Tl;dr: Thermal shock."
],
"score": [
12
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
79mv8w | The Boltzmann brain theory | Repost | explainlikeimfive | {
"a_id": [
"dp37yq1"
],
"text": [
"The 2nd Law of Thermodynamics (which for our purposes says that the disorder in an isolated system can't go down over time) is statistical, not absolute. Over extremely large spans of time, the possibility of a fluctuation from a disordered to a more ordered state in any particular region approaches 100%. An eternal universe spends infinitely more time in it's highly disordered later stages than it's more ordered early stages. Thus, what is more likely: that you are really living on Earth with several billion other humans, 14 billion years from the birth of our observable universe, or that you are a statistical fluctuation of a brain that just came into existence at some arbitrary point in time, structured in such a way that you have memories corresponding to living on Earth with several billion other humans, 14 billion years from the birth of our observable universe?"
],
"score": [
4
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
79uiee | Zoning out while driving and not killing anyone | Repost | explainlikeimfive | {
"a_id": [
"dp4zb32",
"dp573jn",
"dp4yjfd"
],
"text": [
"You go into autopilot, your brain doesn't take logs unless something interesting occurs, but while you're in autopilot you are still actively scanning the road and controlling the car and responding to routine inputs(stop signs, road markings, corners in the road) Once you do a task enough your brain makes an autopilot routine for it, this is why you can walk and chew gum at the same time. Why you can have a deep conversation with someone and walk up a flight of stairs. Walking has been fully automated since you were young, if you think about how you're walking up the stairs it'll be awkward. While you may not remember paying attention it doesn't mean that your brain wasn't paying attention. It just means that this morning's commute was completely uneventful",
"While you are doing something boring and repetitive like driving, you are fully aware and paying attention in the moment. All that happens within the context of your short-term memory. Why you feel like you zoned out is because nothing interesting enough happened to transfer those memories from short-term to long-term memory. You are aware, you just don't remember being aware.",
"To be completely honest, that's probably about half luck and half subconscious. A term they love to use in driver's ed is \"highway hypnosis\" which is basically just what you described, what you're doing is so mundane and consistent that it's practically as automated as breathing, to the point where you end up speeding (or in some cases slowing down, whichever direction your foot decides to go, but generally gravity is the winner there), potentially swerving/drifting until you hit rumble strips, etc and so forth. There are an ton of accidents that result from this situation, but that also has to factor in density of traffic, other people making sketchy choices as they change lanes or merge and the like."
],
"score": [
28,
4,
4
],
"text_urls": [
[],
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[]
]
} | [
"url"
] | [
"url"
] |
|
79vdvk | how can a GPS or in car navigation system work with no internet, but google maps on my phone requires a signal? | Repost | explainlikeimfive | {
"a_id": [
"dp50qrh",
"dp50omp"
],
"text": [
"You don't need a connection to the internet for the GPS, you need it for the maps. GPS just receives a signal from the GPS satellites and uses it determine your location. The maps however needs to be downloaded from somewhere - in your car navigation system the maps are already stored on the device, but in Google maps they are downloaded on the fly.",
"Your phone doesn't save the actual maps of places locally and, by default, downloads them from Google's servers when you use google maps whereas your car's computer just stores them. You can download and store maps on your phone to use google maps offline if you know you'll be without internet. Edit: you need the maps to do anything other than finding your latitude and longitude (i.e. reverse geocoding to turn those coordinates to an address). The GPS itself doesn't require an internet connection, it's all the other data you need to use the maps service that does."
],
"score": [
3,
3
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
7a38wl | How are video games cracked? | Repost | explainlikeimfive | {
"a_id": [
"dp6rswn"
],
"text": [
"Video Games are ran by a set of internal codes. If someone has the appropriate software they are able to see the internal codes (which are hundreds of thousands of pages long). If they are able to get into which line of code contains the players ammunition (for instance) then they are able to modify that line of code to constantly be changed to full ammunition. Cracking is not easy, depends on the publisher really."
],
"score": [
3
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
7a6hpg | If most trees shed their leaves at winter, does that mean there is less oxygen in the winter months due to photosynthesis? | Repost | explainlikeimfive | {
"a_id": [
"dp7im9v"
],
"text": [
"Yes, there is seasonal variation in atmospheric oxygen concentrations, but it's important to note that trees are not the primary source of atmospheric oxygen. Most of the oxygen in the atmosphere comes from phytoplankton in the ocean."
],
"score": [
5
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
7a72tt | What is subnetting? | Repost | explainlikeimfive | {
"a_id": [
"dp7pnkb"
],
"text": [
"It's a way to divide up the IP addresses of the Internet so everyone can find them (4+ billion of them on the IPv4 Internet). Every computer, phone, etc, can't keep track of billions of addresses and how to reach them, so grouping them into subnets is necessary. It's like phone numbers - +1 (555) 555-5555. The +1 means the U.S. The (555) is an area code (or NPA) inside the U.S. The 555- is an area within that area code (NXX). And then the 5555 is one of 10,000 possible phones in that area. If I make a call to my local NXX, the local switch knows where all those numbers are. If it's not in my local NXX, but it's in the same area code, it can send it to a nearby switch that would know where those 10,000 numbers are. If I call out of my area code, the local switch doesn't need to know all about the number, but will know from the country code or area code that it should send it to a long distance provider / switch. Dividing up the address space is necessary so everyone doesn't need to keep and update a list of billions or trillions of numbers and where to find them. You keep track of your local numbers and make sure everyone else knows that you've got that block of numbers so they can reach you."
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7a8xgy | why do things get darker when wet? | Repost | explainlikeimfive | {
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"text": [
"When things are wet they have a layer of water over them. Light hits the surface, and some of it gets absorbed, then light hits the object and bounces back, but some of it is absorbed again. As the light goes back through the water layer, some is absorbed, some goes through and some more goes back towards the object. So when things are wet less light can reflect off of it and into your eyes.",
"Imagine light is food. When you add water to things it eats up some of that light. So when you look at it it is darker."
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7aa6ch | Why does wind or moving air in general feel cooler than the surrounding air? | Repost | explainlikeimfive | {
"a_id": [
"dp8bypd"
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"text": [
"Humans produce heat so any wind that passes us removes some of our own radiated heat. Like blowing on hot food. Even though the wind may be hotter it will still feel cooler when it blows by because instead of our heat adding to the heat from the air at least now our radiated heat is being pulled away."
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7abpar | What physically is a smell? | Repost | explainlikeimfive | {
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"text": [
"Odors comes from molecules that have evaporated into the air, the same way water becomes water vapor. Your nose has thousands of receptors, each tune to a particular kind of molecule. When a molecule binds to them, it sends a signal to our brains we interpret as a particular smell."
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7af7zp | Why are there no green flowers? | Repost | explainlikeimfive | {
"a_id": [
"dp9giie"
],
"text": [
"The point of flowers is to attract pollinating animals like insects and birds. It's essentially a lure to get such animals to approach the flower (and the right part of the flower) to collect and distribute pollen. That said, [there are green flowers]( URL_0 )"
],
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7aidb1 | How does hypnotism work? Are all people susceptible? | Repost | explainlikeimfive | {
"a_id": [
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"text": [
"In psychology, we've figured out that hypnotism isn't really a thing. Any effect attributed to hypnotism is almost entirely due to to the \"hypnotized\" person being willing to trick themselves into believing it is working, so they just go along with whatever the hypnotist is suggesting. It's a placebo effect."
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7aits9 | What’s the science behind “Best used By” dates on food? | Repost | explainlikeimfive | {
"a_id": [
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"text": [
"Varies depending on the food, but basically we store it as intended and watch it/taste it. Mostly you only have to do this for parts. So while a cake will last a long time, cream won't so we don't test a cream cake since we know it will be off when the cream will be off, and the dates for typical cakes and creams are widely known. In some cases there is no method and it is simply a case of \"We are legally required to put a date on this food, so here is a date.\" Tinned food for example will last indefinitely without spoiling yet has a date printed on it for legal reasons. Other times it is an extrapolation. Bottled water for example *does* expire because the plastic leeches into the water. We can take a few samples and then extrapolate that the water will no longer be fit for consumption by a certain date."
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7aiw1u | Why does the the thermostat need someone to direct it to either heat or cool the room? Why isn't just providing the desired temperature enough for the system to figure it out itself? | Repost | explainlikeimfive | {
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"Because that’s not usually a desirable feature. For example, I have my thermostat set to 65 and heat because it’s starting to get cold. If the temperature gets a little higher than that, I’m not going to complain, I just don’t want it to go lower. The opposite is true in the summer. I’ll set my thermostat to 78 and cool. If the temperature drifts down to say, 75, why would I waste energy bringing it back up to 78 when I’m trying to stay cool?",
"Most new thermostats have auto feature where you set range and it does just that. Personally, I don't use it because I feel like both turning on in the same day might break something. I have no evidence of that, just crazy.",
"If the room is set to cool at 72, but the thermostat reads the air as 68, the system won't kick on, because it knows it is cold. I am not an HVAC tech, so I don't feel qualified to answer the other piece, but maybe because it would be incredibly inefficient to keep switching back and forth around a temperature, and stressing on the components.",
"My Google Nest does. Most thermostats you install yourself will take a range and keep it inside that range. You're probably confused by older thermostats and/or new building thermostats. With new building thermostats it's fairly simple - the builders were cheap and a fancy thermostat costs more.",
"Newer thermostats commonly come with heat, cool, and auto settings for the mode of operation. The auto setting usually incorporates a programmable deadband that is factory set to 5 degrees. when changing the heating setpoint in this mode from 67 to 68, you’ll notice the cooling setpoint raise from 72 to 73. This allows the HVAC system to run without “fighting” itself. It works well, but i’ve seen most customers prefer the swap modes manually."
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7ankug | Why is the moon so much smaller on my phone's camera than what it looks like with my eyes? | Repost | explainlikeimfive | {
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"Your phone's camera uses what's called a wide angle lens. Because of the wide angle lens, it looks at a wide area all at once. This is good for taking group photos and pictures of things nearby, but when you take a picture of something small or far away like the moon then your phone's camera is looking at not only the moon but a lot of space around it. Your eyes are different. You see a smaller amount at once and your brain makes this even more apparent because you're able to focus on little details of things thanks to your \"fovea\". The fovea is a little patch in the back of your eye which makes your eyesight its absolute best right in the middle of what you're looking at.",
"Your phone camera has a wide angle lens. This allows you to fit more stuff into a single shot, but the side effect is that everything in the distance becomes smaller to fit into the frame. The same thing happens with the moon. Since it is far away, it becomes smaller on a cell phone camera picture. The opposite is also true: if you take a picture of the moon using a telephoto lens, the moon can appear absolutely massive relative to the foreground.",
"Some of this is in your mind. Your impression of an object's size is subconsciously adjusted on the basis of many cues. For example, people automatically have an impression of an object's actual size independent of how far away it is. It's well known that the moon seems to us to be bigger when near the horizon that when it's high in the sky. Some the effect is because human eyes have better dynamic range than cameras, or at least than JPEG files. If you point your camera towards the dark sky it will automatically try to adjust to brighten the image. Probably all the pixels of the moon will be at maximum brightness, allowing no way to see any features. Even though the moon is quite a dark grey object, it's also a sunlit object so daytime exposure settings are more appropriate than night-time ones. Without a very long lens it will take up such a small percentage of the image that any automatic exposure system will largely ignore it. Phone cameras typically don't have manual settings."
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7aqits | How does anti-dandruff shampoo like Head & Shoulders for example work? Does it really help to decrease amount of dandruff and HOW? | Repost | explainlikeimfive | {
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"text": [
"Mostly, it contains a fungicide which kills the microscopic fungus (similar to a yeast) that causes much dandruff. It also sometimes contains a moisturizer which can help if dry scalp is adding to your dandruff."
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7axiu4 | How does a Jet Afterburner work? | Repost | explainlikeimfive | {
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"text": [
"Raw fuel is dumped in to the exhaust pipe and is ignited to create the thrust. If you are interested in jet engines and How they work, here is a cool YouTube channel about jets, their working and maintenance of them URL_0",
"It's actually neither of those. Afterburners simply inject fuel downstream of the turbine, where it burns, increasing the velocity of the exhaust, hence increasing the speed of the plane. This comes at the cost of being incredibly fuel inefficient."
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7aznxb | CPU cores, logical cores, threads, and hyperthreading, and how they all work together? | Repost | explainlikeimfive | {
"a_id": [
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"text": [
"Yer not alone in askin', and kind strangers have explained: 1. [ELI5:CPU Hyper-threading and Threads ]( URL_7 ) 1. [ELI5: Hyperthreading ]( URL_4 ) 1. [ELI5: How Hyperthreading works/what Hyperthreading is ]( URL_0 ) 1. [[ELI5] Why does Intel Hyper-threading use only 2 threads per core(1 physical core as 2 logical cores), why not more? ]( URL_6 ) 1. [ELI5: What exactly is the difference between \"cores\" and \"threads\" on a CPU? ]( URL_3 ) 1. [ELI5: What is hyper-threading? ]( URL_1 ) 1. [ELI5 Someone explain CPU cores to me ]( URL_2 ) 1. [ELI5: How hyper-threading works and why we can't have a core hyper-threaded more times. ]( URL_8 ) 1. [ELI5: How does hyperthreading in Intel CPUs work? ]( URL_5 )",
"A **CPU core** is a processing unit. In a multicore chip, each of them functions as a regular single core processor, but they usually share cache memory. Therefore they are bound to some synchronization issues, and a 4 core processor doesn't guarantee a 4x increase in performance over a single core processor. A **thread** is a sequence of instructions executed on a core. Usually this is one process at a time, but a thread may switch between processes rather quickly. Since not all instructions require the full hardware of a core, smart scheduling can use these unused resources for instructions of a second thread. With small hardware adjustments as well, one physical core can simulate multiple **logical cores** which each handle a thread. This is called multithreading, and usually done for two logical cores per single core. Intel calls its implementation of this **hyperthreading**, AMD calls it **Simultaneous Multithreading** (or SMT)."
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"https://www.reddit.com/r/explainlikeimfive/comments/mq98c/eli5_how_hyperthreading_workswhat_hyperthreading/",
"https://www.reddit.com/r/explainlikeimfive/comments/2xqf8s/eli5_what_is_hyperthreading/",
"https://www.reddit.com/r/explainlikeimfive/comments/4pjtim/eli5_someone_explain_cpu_cores_to_me/",
"https://www.reddit.com/r/explainlikeimfive/comments/5xcjnc/eli5_what_exactly_is_the_difference_between_cores/",
"https://www.reddit.com/r/explainlikeimfive/comments/33cx7e/eli5_hyperthreading/",
"https://www.reddit.com/r/explainlikeimfive/comments/1ywzbk/eli5_how_does_hyperthreading_in_intel_cpus_work/",
"https://www.reddit.com/r/explainlikeimfive/comments/51ivxt/eli5_why_does_intel_hyperthreading_use_only_2/",
"https://www.reddit.com/r/explainlikeimfive/comments/1y8q7m/eli5cpu_hyperthreading_and_threads/",
"https://www.reddit.com/r/explainlikeimfive/comments/43hk9x/eli5_how_hyperthreading_works_and_why_we_cant/"
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7b0d2w | How does a lie detector work? | Repost | explainlikeimfive | {
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"text": [
"It doesn't. There is absolutely no proof that any purported \"lie detector\" test (polygraph, VSA, etc) actually works. The inventor of the polygraph actually said many times that it doesn't work. Polygraphs claim to detect falsehoods by measuring heart rate, respiration, blood pressure, and galvanic skin response. They may accurately measure those things, but none of those factors are related to lying in any meaningful way.",
"Well, first lets get this out of the way: it doesn't measure lies. What a lie detector measures are physical stress responses. It measures very small physical responses like heartbeat, blood pressure, muscle contractions etc. The idea is that if someone lies, they are going to be more stressed out about that then when they are telling the truth and the test will show that. In reality, these tests are bunk. People can have stress responses for any number of reasons (like, say, discussing an incredibly traumatic thing) and similarly, plenty of people can lie without having any bodily response whatsoever (plenty of murderers that passed polygraph tests)"
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7b2417 | How do aircrafts know when they are being targeted? | Repost | explainlikeimfive | {
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"Two basic ways: Sensors on the aircraft detect the targeting radar of a ground installation or missile being pointed at the aircraft. Radars depend on hitting a target with energy and then detecting the energy as it bounces off the target and returns. Planes can detect when a radar is simply scanning the whole sky and when it is focused specifically on them by analyzing the radar energy hitting the plane. Missile Approach Warning systems scan the sky for missiles using pulse-doppler radar, infrared, and ultraviolet sensors. The radar can quickly detect objects moving fast towards the aircraft, and the IR/UV sensors look for the bright light produced by the missile's rocket motor.",
"Most commonly used missiles and platforms capable of firing missiles use radar to detect and range their target. Military aircraft are equipped with radar warning receivers. Signals from antennas placed on the aircraft pick up radar pulses then send them pulses through the radar warning receiver where they are processed. Each type of radar platform has a unique signature based on things such as frequency and pulse width. The radar warning receiver is pre-programmed to identify these radar signatures and alerts the pilot if a detected signal matches a known threat. If the threat is the radar from a missile, it will make a \"beep beep beep beeeeep,\" prompting the pilot to take evasive action and/or launch countermeasures. Source: Engineer that makes radar warning receivers."
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7b3e4k | Why is cancer so hard to cure? | Repost | explainlikeimfive | {
"a_id": [
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"text": [
"A \"cure for cancer\" will NEVER exist. Cancers are a huge number of widely varied diseases, the only common link is out of control cell reproduction. There are so many types and subtypes it's insane",
"It is so hard to cure because it's not caused by a germ or a bug. It is parts of your own body that decides to grow in a way your body doesn't want it to. And to get rid of cancer, doctors have to figure out a way to kill your bad cells without also killing your behaving cells.",
"We can't. There is no cure for cancer. That sucks to say, but it is true. There are so many different types of cancer that finding a cure for cancer is impossible. Cancer manifests itself in so many different ways, that have so many different behaviors, that curing it is functionally impossible. Cancer also has the nasty fact of being normal cells that have gone rogue. So killing the tumor without killing the surrounding healthy cells is difficult. Many, many different things kill cancer cells. Far fewer do that without colossal risk to patient. I'm not an oncologist, so I'm sure one will come along and dunk on my answer in terms of depth but that's the gist of it."
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7b4as1 | What is depression and how is it different to being sad and unmotivated? | Repost | explainlikeimfive | {
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"> Sadness is a normal human emotion. We’ve all experienced it and we all will again. Sadness is usually triggered by a difficult, hurtful, challenging, or disappointing event, experience, or situation. In other words, we tend to feel sad about something. This also means that when that something changes, when our emotional hurt fades, when we’ve adjusted or gotten over the loss or disappointment, our sadness remits. > Depression is an abnormal emotional state, a mental illness that affects our thinking, emotions, perceptions, and behaviors in pervasive and chronic ways. When we’re depressed we feel sad about everything. Depression does not necessarily require a difficult event or situation, a loss, or a change of circumstance as a trigger. In fact, it often occurs in the absence of any such triggers. People’s lives on paper might be totally fine—they would even admit this is true—and yet they still feel horrible. > Depression colors all aspects of our lives, making everything less enjoyable, less interesting, less important, less lovable, and less worthwhile. Depression saps our energy, motivation, and ability to experience joy, pleasure, excitement, anticipation, satisfaction, connection, and meaning. All your thresholds tend to be lower. You’re more impatient, quicker to anger and get frustrated, quicker to break down, and it takes you longer to bounce back from everything. [Source]( URL_0 )",
"Depression and unmotivated can go hand in hand. Sadness can cause depression. There are a lot of different kinds of depression. Often people who suffer from chronic or repeating depression don't have a known emotional reason for the said depression (this is not counting people who faced trauma and abuse). I have Major depressive disorder, I occasionally get a week or two where I start to feel worthless, meaningless, unwanted, not valued, and I just want to escape people and beat myself up. Over years of therapy I've been unable to figure out any known cause or trigger. It just happens.",
"Definitely not a doctor or psychologist, but I can give a patient point of view. I’m not depressed now but I was for quite a long time. It’s kind of like, I’m bad at explaining... sleeping because you’re too tired to stay awake and you know you’ll feel better later vs sleeping because you’re too tired of being awake. I guess it feels like being forced to do something as opposed to choosing to do something in a way. When you’re sad you cry but when you’re depressed you sleep. Everything feels hard and crying is way too much energy. You want to lie down and stare at nothing because you genuinely don’t have enough energy to even be sad. I’m sorry I tried super hard to explain that, it was better in my head.",
"- Hey, how's it going? - Not good. Everything feels like a chore, I don't even want to draw, I have to remind myself to eat, I could barely brush my teeth this morning, I'm always tired, I don't know why I'm even doing anything. - Oh dear. You've been like this for a while, huh? What happened? - Nothing. Absolutely nothing. I just feel like shit for no reason. When my mum asks me how I am and I say something like \"meh, could be better...\" she often asks me why and there's absolutely nothing I can say because there IS no reason. Sure, sometimes I can point to some event that triggered my current depressive episode. But even then, it's usually something that shouldn't completely incapacitate me and take me weeks to get over. For depression to be diagnosed it has to last for at least two weeks and (severely) impair your ability to function. It's not (necessarily) feeling bad about something that happened, not feeling like doing something. It's a constant weight on you that makes it hard or impossible to do what you KNOW you should / need / even want to do. It's feeling low and at the same time not having a clue why. It's feeling like a lazy piece of crap because you can't get your shit together and clean your room and take out the trash even though you actually WANT to do it. I really do WANT to do the dishes every evening, it would take me 5 minutes maybe if I did - but far too often, especially during severe episodes, I just physically cannot do it, my body won't move, no matter how much I yell at myself, encourage myself, try to think of rewards for myself. Depression is \"in your head\" in the truest, literal sense. It's your brain chemistry not working as it should. Certain chemicals that are necessary for your brain to do what it needs to, for your brain's commands to properly be submitted to the rest of your body, aren't available in sufficient amount or not at all. Serotonin for example is part of a group of what's colloquially called \"happiness hormones\". Some depressed brains reabsorb any serotonin produced too quickly so the hormone can't take effect. That's where drugs called SSRI's come in: the acronym stands for selective serotonin reuptake inhibitors. They prevent the reuptake of the serotonin, so the hormone can do its job. So unlike what most people experience every once in a while, when they feel sad or unmotivated, this is an actual physiological issue.",
"Let me preempt by saying I work in this field. Depression is persistently feeling sad until it affects your life negatively in some way. Bonus: For specific criteria read up on dsm or icd (mostly used for research/clinical work). Anyone can feel sad when something sad happens. This is normal, but normally we all recover somehow and life goes on. Being unmotivated can be a symptom of something, however, it by itself might not mean you have depression. There are many reasons (often normal) why one might be unmotivated to do something or everything, and again this might be normal.",
"It’s like every day is cloudy, all your extremities weigh 500lbs, you took five Benadryl and can’t think and for some reason you don’t care about anything. You’re just there",
"> Now and then, there’s some task you just have to do. You really don’t want to, you’d rather put it off until later — but you’re an adult, and you know it’s important. So you suck it up, and you get it done. Maybe it’s doing some D.I.Y. around the house, maybe it’s going to the dentist, doing your taxes, whatever it is — you really don’t want to do it but you make yourself do it anyway. --- > Imagine if each morning, you felt the way about getting up the way you did about that difficult task. This is different from just not wanting to get up — you want to get up, you know you need to get up, but it feels like a huge amount of effort. If it’s now and then you could handle it, but instead it’s every single morning. --- URL_0",
"Honestly, the comic Hyperbole and a Half described it EXTREMELY well from a first-hand point of view. Be sure to read both parts. [part 1]( URL_0 ) [part 2]( URL_1 )",
"So, being hungry kind of sucks, but it's usually a passing thing. You know where it comes from - lack of food, boredom, exercise, and so on - and you know what to do to remedy the feeling. You eat. There's a chemical mechanism in your body that tells you it wants food, and then when you give it food, it gives you positive feedback. Sadness is not too different. It sucks, but usually you know where it comes from, and you know what needs to happen in order to feel better. There's a chemical mechanism in your body that makes you sad, and when you get over the reason or something nice happens, it gives you positive feedback. Now imagine that you're hungry even though you just ate. And eating does nothing to fill you up. The chemical mechanism that drives you to do something and then rewards you for doing it is *broken*. You know exactly what you'd usually have to do to feel better, but it *doesn't work*. After a while, you stop doing those things, because they're pointless anyway. After a while longer, you feel like a failure because you know, rationally, that the task that you need solve is so *easy*. You enter into a vicious cycle because the mechanisms to beat you down still work perfectly, but the mechanisms that enable you to experience satisfaction and rewards do not. That's depression. One of the deadliest diseases that exist.",
"Depression is the absence of emotion. Or a muffled sense of emotion. You can't feel happy even if you win something. You won't feel excited even if you get a free vacation to Paris. You might feel extremely sad though. But that too will grow muffled with time. You won't be too shocked by anything. It's a feeling of emptiness...or maybe see talks by Andrew Solomon on depression. He explains it really well.",
"depression can present itself in so many different ways. For many, it turns into almost complete lack of energy and life force. For me, it shows itself through mild drug abuse and crying all the time because everything is horrible and I'm most horrible of all. It just depends on the person. I used to get sad, but it never resulted in laying in bed for weeks doing nothing but hating myself and everything around me. Many depressed people get unmotivated. The difference, I think, is sheer scale. Sadness, non motivation bug you for a bit, but depression will kick your ass for years on end if you don't take proper steps to help it."
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"http://hyperboleandahalf.blogspot.com/2013/05/depression-part-two.html"
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7b7dfa | How do we know global warming is different than something like the "Medieval Warm Period", and that it is not just another anomaly? | Repost | explainlikeimfive | {
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"text": [
"Frankly, we've already out done the Medieval warming by an order of magnitude today, and that's not including what we predict will happen, only how much the climate has already warmed. Rather than deeply explain it, I give you this webcomic: URL_0 (Your medieval warm period is listed by name near the bottom.)"
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|
7b7s32 | How is it possible for us to know if a sound comes from the top or the bottom given that we only have two ears aligned horizontally? | Repost | explainlikeimfive | {
"a_id": [
"dpfwx2j",
"dpfvcar"
],
"text": [
"The shape of your ears directs sound into your ear canals difforently based on the angle it comes in at. If you change the shape of your ears with something like play dough you lose this ablilty all togeather. Other animals like dogs aren't as good st this and so tilt their heads to get a better idea of what virtical angle the sound is coming from. Here is a great video by Smarter Every Day all about it: URL_0",
"It's difficult for human to determine the height of a sound. Owls for example have an ear higher that the other to better be able to locate sounds"
],
"score": [
5,
4
],
"text_urls": [
[
"https://m.youtube.com/watch?v=Oai7HUqncAA"
],
[]
]
} | [
"url"
] | [
"url"
] |
|
7bbsj6 | How did the 40 hour week, or 8 hours a day for 5 days, for jobs become the standard for a full time job, and why is anything less or more considered part-time or overtime respectively? | Repost | explainlikeimfive | {
"a_id": [
"dpgrwdg"
],
"text": [
"Early 20th century, for the US anyhow. There were a lot of protest for fair wages, and reasonable hours, after a while companies realized production and quality improved with workers who were not working 80 hours and starving."
],
"score": [
4
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
7bdhvq | Legally how are Samsung allowed show Apple products and logos in their new advert? | Repost | explainlikeimfive | {
"a_id": [
"dph2yso",
"dph3lwa"
],
"text": [
"There's no law prohibiting it. The same thing is common in car commercials showing how one brand has better technology or towing capacity than the competitors. Look at the ad where chevy trashes ford for their aluminum by dropping a load of bricks in each",
"So long as it is not misleading advertising and only represents facts, most jurisdictions allow direct advertisment. Its just not always good for PR obviously cause its a direct jab at your competitors."
],
"score": [
4,
3
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
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