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7dqf2x | Why do we "shiver" when we get past a certain level of cold? | Biology | explainlikeimfive | {
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"When you shiver, it's simply your muscles quickly contracting and releasing. This generates heat, which in turn increases your core temperature, and you will be \"less cold\""
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7dqghq | Why do some things melt when heat is added, such as ice, and others harden, such as clay? | Chemistry | explainlikeimfive | {
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"Clay hardening is due to water leaving it. Ice melting is a state change, where the material changes state from solid to liquid. If you take clay to a high enough temperature, it's insides will melt too (barring any chemical reactions)"
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7dr21z | Why do planes need to turn? | Why do planes need to turn and bank. Couldn't they just point in the direction they need to go and fly there? If LAX was say 273° west, why wouldn't they aim the plane at the direction and just fly straight? | Other | explainlikeimfive | {
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"Planes don't turn mid flight for the most part. They do excalty as you describe. They do however turn, near the runway usually, for numerous reasons. Most obviously, the runway isn't aligned with the direction of travel. Or others, like they have other aircraft to schedule around with landing. Weather conditions require a certain runway direction. There are unforseen delays causing them to circle. There is unfavourable weather (or airspace) they wish to avoid. Etc. Unless you mean [this type of \"turning\"]( URL_0 ). Those aren't turns, they are straight lines distorted by trying to make a flat map. On a globe, they are the straight path.",
"Traffic. You have multiple planes coming in (or going out) from different directions, but they all need to be in an ordered line to land (or get out of the way). IANAP but I believe this is what they call \"flying in the pattern.\" Also, the direction of the runways are not all the same. So if you take off from LAX, you're going to be roughly headed east or west. If you're going to SFO, PDX, or SEA, you have to turn at some point. PDX faces E/W, SFO is diagonal to the four cardinal points, and SEA is N/S. The only way your hypothetical makes sense is if you take off from LAX, and go east, landing at an airport with roughly the same compass heading.",
"Planes have to take off of runways that are at specific directions, so they have to turn to go toward their destination. Hey also need to be able to get into approach patterns without colliding into other aircraft landing around the same time from other destinations. And then there may be things like airspace restrictions, weather, jet stream, etc. that they need to maneuver around.",
"Planes can turn for many reasons, here are a few of the main ones: - **Weather:** Updrafts and downdrafts are columns of air moving vertically. These can cause the plane to \"bump\" or drop, sometimes violently. The main reason the captain switches on the seatbelt sign for turbulence is that hitting a downdraft can bodily throw people into the roof, causing severe injuries. Storms are just unsafe, or best avoided. Clouds can contain hail which will badly damage an aircraft, and icing (water vapor freezing on the wings) can reduce the lift generated by the plane. - **Speed:** There are jet streams in the higher altitudes. Small streams of air that the plane can \"ride\" to get to its destination faster and with less fuel. Think of them like rivers. When moving from place to place, it's often faster to go to a river and ride the current, versus taking the more direct over-land route to your destination. - **Traffic:** There are [lots of planes]( URL_1 ) in the air. Around airports air traffic controllers create \"stacks\" where planes circle around and around the same point at different heights. When you're waiting to land at a busy airport, you're generally in a stack. If a particular airport is very busy, sometimes the area controller will make the plane take a longer route so that it arrives at the airport where there's a gap for it to land. - **Safety:** After the Malaysian airlines flight [MH17]( URL_0 ) was mistakenly shot down, planes diverted around the Ukraine. Most airlines are avoiding Syrian airspace at the moment too. Most airliners fly too high to be at risk from most weapons, but there's always a risk."
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7dr9f2 | What are we actually referring to when we say someone has “writer’s block”, and why does it occur? | Biology | explainlikeimfive | {
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"It's a euphemism for lack of inspiration. Source: Am a man that sometimes lacks inspiration"
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7drezr | Why does tap water taste worse after only a couple of hours? | I've noticed that normal bottled water can sit open for a day or longer and taste all right if it's not in the heat, whereas water from tap almost immediately tastes even worse than it did merely hours before. What causes this? | Chemistry | explainlikeimfive | {
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"Just saw a [YouTube video]( URL_0 ) about this sort of thing the other day. It could be that your tap water always tastes like that, but when it's cold your tastebuds just can't tell."
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7drntx | What exactly makes it so hard to replace a human body part with another body part from a different human? | I heard about the doctor's head transplant project and I always thought that i would be very difficult because of, not just that reattachment of the bones, tissues, nerves, muscles and the imprecise tools, but i always thought that bodies have this ability to reject other body parts that isn't theirs | Biology | explainlikeimfive | {
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"Yes our immune systems will reject many things the body finds to be foreign. This happens with skin and organs and even artificial elements like metal or plastic. Before and after a transplant, they give you a lot of different drugs to help suppress your immune system until your body really takes hold to the new part. It’s never a guarantee though, a body can still start to reject an organ after it seemingly works for a long time.",
"With the head transplant, one of the major barriers is attaching spinal nerves. We can't get one person's severed spinal nerves to re-attach and function, and we have far less idea about how it would work between two different people. The doctor's methods are untested and unproven. I haven't even thought much about the immune rejection (immunology is not my area), but I doubt the poor bastard he ends up trying this out on will survive that long."
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7ds31w | What is that blurry sensation we get when we’re lying down and get up too quickly? | The best way I can describe it is feeling my head really heavy and then hearing like a buzzing sound and my vision goes all blurry and red-ish. This happens to me several times a week. Does it happen to anyone else as well? And, can someone explain what this is? | Biology | explainlikeimfive | {
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"Postural hypotension. You're getting up too fast and low blood pressure to your brain is causing the other symptoms. This can even knock you out entirely. Get up a little more slowly to give your body a chance to raise the blood pressure to your brainmeats.",
"It's called orthostatic hypotension. It is because your bloodpressure can't correct itself fast enough going from lying down to standing up. When you ate lying down your blood doesn't have to be transported vertically so your vessels can relax a bit and your body has to work less hard to keep everything going. When you stand up fast you get the component of gravity back and the blood will be pulled towards the ground until your vessels react and contract to keep a steady bloodpressure everywhere in your body. When you have a low bloodpressure in general or when your vessels can't react(fast enough) you get a temporary drop of bloodpressure to your brain which could even lead to fainting if it is severe enough or lasts long enough. It can help to stand up slow or eat a bit more salt(if it's due to low bloodpressure.)"
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7ds6s3 | Why do lighters have smaller flames when cold and bigger flames when warm? | Chemistry | explainlikeimfive | {
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"Butane gets thicker when cold so it doesn't come out as fast so it only produced a small Flame.",
"Butane boils at 30f degrees. The only reason it's a liquid is because the pressure forces it to be that way. When you hit the button, the open valve lets the butane literally boil and steam out. The lower the temperature, the slower the boil. Below 30 degrees lighters don't work at all because there's no pressure."
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7dscol | water is h20 , hydrogen peroxide is h202, how can one extra oxygen molecule turn into something that can kill you | title. | Chemistry | explainlikeimfive | {
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"Short answer: because changing even one element in a compound will drastically change how it interacts with other chemicals. Long answer: H2O is remarkable stable and wants to stay that way. H2O2 is still stable, but it will give the extra oxygen atom to any compound that it can, so it can be more stable. Unlucky for living things, cell membranes will end up taking this extra oxygen and they will no longer be able to hold their form. Once the cell membrane falls apart the cell will die.",
"WOOOOOW literally every one of these answers are wrong. H2O2 does not kill cells with a free O atom going about grabbing up different things. In fact free O molecules happen all the time thanks to our Electron transport chain. It just bonds with H and creates water. The molecular structure of H2O2 is H-O-O-H, with those dashes being bonds. The middle bond is where the hydrogen peroxide breaks into two components producing 2 OH molecules. Now OH isn't bad. In fact our body is full of OH- molecules. Water is constantly losing and gaining hydrogen. This gives a mixture in pure water of H2O molecules, HO- molecules and H3O+ molecules. This is the whole bases for the pH system (p=-log: 14= -log[H] + -log[HO-]). So why does H2O2 kill? The answer is quite radical! (you'll see what I did there in a second) When H2O2 breaks they create two OH radicals. A radical is any molecule with an odd number of electrons. So their is one unpaired electron in it. Molecules/Atoms HATE this. In the body biologists call these Reactive Oxidative Species (ROS). Radicals will then go through radical reactions with any molecule in their way. So these reactions caused by ROS are incredibly detrimental because by stealing 1 electron from another molecule the ROS stops being an ROS, but the other molecule becomes one, so the reaction is maintained. All cells do have mechanisms to address this because cells do create radicals all time, but by dumping H2O2 on cells it overloads the system killing the organism.",
"Basically H2O2 has the ability to form an OH radical. Radicals are molecules with an unpaired electron hanging around. Unpaired electrons are not stable so they attack other things, like cell membranes. So if they attack the cell membrane, everything leaks out which is bad news.",
"In water, oxygen is attached to two hydrogen atoms, like this: **H--O--H**. These hydrogen atoms are really just protons, and they don't care too much about the electrons that they share with oxygen (the dotted lines in the picture above). This is why it's easy for one to leave the electrons behind and go off and do its own thing (free hydrogen ions are what make things acidic). On the other hand, oxygen is an electron hog, i.e. it's highly electronegative. It's extremely difficult if not impossible to take electrons away from oxygen, like you can from hydrogen. (in chemistry, when we take electrons away from something it's called \"oxidation\" because it's what oxygen always does) Hydrogen peroxide is a completely different molecule. Its structure is like this: **H--O--O--H**. That single bond between the two oxygens is not very strong. Each side of the molecule is pulling on that bond in the middle with equal strength. Because of the symmetry, when the bond breaks, you're left with two molecules that have a *single unpaired electron*, because the bond itself was originally two electrons. Electrons don't like to be unpaired, it's a quantum mechanics thing. When peroxide decomposes, each oxygen takes one of the electrons from the original bond. The two molecules it breaks up into are called hydroxyl radicals, and they look like this: **H--O***. That asterisk represents the unpaired electron. Now that unpaired electron is a huge problem. In fact, free radicals are pretty much the most reactive compounds known. It especially likes to find double-bonds or aromatic rings to attach to (ELI15). And guess what has lots of those? Pretty much all the most important biological macromolecules, like DNA and proteins. It's a really big problem when free-radicals can sneak past all your body's defenses and damage DNA. Fortunately, your body has lots of ways of absorbing free-radicals. This is why it's not a big deal to spill low concentration peroxide on your skin."
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7dsie3 | Why does water burn skin at far lower temperatures than air does? | For example, a human can easily endure a 90 °C (198°F) sauna for 15 minutes. Whereas human skin will burn in just two seconds in just 65°C (150°F) water. ELI5 please. | Chemistry | explainlikeimfive | {
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"Because water is far more effective at transferring heat to you than air is. It's the same reason why if you put your hand in a 200C hot oven, it'll feel hot but won't burn you unless you hold it in there for quite a few seconds, but if you so much as brush one of the metal shelves you'll get an instant burn. Everything in there, the air, and the shelves are all at 200C but air is terrible at transferring heat and metal is very good at it. Another example is why at room temperature, a wooden spoon will feel warmer to you than a metal spoon in the same environment, because the metal pulls the heat *away* from you way more effectively. Your body interprets that as feeling colder, despite them logically being the same temperature to begin with. Air being so bad at transferring heat is why you have to put thermal compound on the bottom of a computer processor cooler, to fill those microscopic air gaps with something that can transfer heat a lot more effectively.",
"Recently learned this in school. It has something to do with the heat capacities but let me explain the basics to you. Air is a very poor conductor of heat, and molecules carry very less thermal energy compared to liquid. Plus, in air, the molecules aren't as dense as they are in liquid so that means there's less thermal energy in the same surface area (your skin). So basically the molecules in water are denser, so they carry more thermal energy per surface area that they make contact with. Air can't transfer the heat to your body as fast as the water.",
"Another interesting example of this is outer space, which is -270C (-455F). A lot of people think if you are exposed to the vacuum of space with no space suit you would instantly freeze because it is so \"cold\". But this isn't the case at all. Since space is a vacuum there is nothing for your body to conduct its heat into, so it is actually very difficult to cool down because you are limited to only what your body can radiate. This is actually a big challenge for engineers who work on satellites, the space station, and other space craft which need to be designed to effectively radiate waste heat so they don't overheat and fail."
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7dsto6 | How does a drug overdose kill you? | What happens in your body that might end up being lethal? | Biology | explainlikeimfive | {
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"Depends on the drug. Heroin and other narcotics cause severe central nervous system depression which leads to respiratory failure (you stop breathing). If it is something that causes stimulation to the sympathetic nervous system, like cocaine and meth, they can cause heart failure or even rhabdomyolysis, which is break down of muscles that is so severe that calcium and potassium will release into the bloodstream and cause the heart to go into ventricular fibrillation, which will result in cardiac arrest. Over the counter drugs like ibuprofen and Tylenol, among many other drugs, are eliminated by your kidneys and liver. Too much causes severe damage to those organs and they shut down.",
"Depends on the substance. Opioids essentially put you to sleep and turn off the part of the brain that controls breathing. Stimulants such as cocaine or meth can cause your heart to beat so fast it throws itself out of whack (arrhythmia). Or your blood pressure could raise to high enough levels you injure your organs. Overdosage of blood pressure meds can drop your pressure to levels so low your organs aren’t getting enough blood to work. Meds you take for irregular heartbeat will cause other irregularities and your heart won’t be able to pump properly. Blood thinners will make your blood too thin and you can bleed out either from cuts or small holes in your vessels. Overdose on chemotherapy? That’s a slow death where your body stops producing blood cells. Tylenol? Liver failure due to your body trying to break it down and making a poisonous byproduct. Slow, painful, and overall not recommended. Aspirin, ibuprofen, etc? Large doses will cause the balance of substances in your blood to get out of whack. pH, specifically. Possible kidney failure. There are many, many more physiologic mechanisms and drug dosing is a balance between the effect we want and minimizing effects we don’t want. Some of these effects can be due to ingesting a lot all at once, while others can be due to a smaller amount over a long period of time. Source: pharmacist who still remembers a bit from toxicology. I might have mixed a few things up as I haven’t used the knowledge in a few years, but for the most part it should be accurate.",
"Just to add. You can overdose off of just about anything. Everything you consume has some level of chemical effect on your body and organs. Those organs can only stand so much before they fail. So too much of something (even vitamin C or chocolate) can reach that breaking point.",
"There are two main problems. Either it suppresses a function of the body that is needed for survival, breathing, nerve function, heart beating etc. Or it poisons and kills organs needed for survival. Take an overdose of a typical opiate, and it suppresses muscle coordination and nerve conduction, this usually leads to paralysis of the diaphragm muscle you use to breath and the person suffocates. Contrast that with tylenol (paracetemol for our Euro cousins) overdose which poisons the liver, causing you to die a prolonged and quite painful death as the dying liver spreads toxins to every corner of the body poisoning you from the inside out."
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7dsvk4 | How can the gunpowder inside the ammo shell explode of there's very limited oxygen for combustion? | Chemistry | explainlikeimfive | {
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"The gunpowder has a chemical in it which contains oxygen (known as an oxidizing agent), this chemical donates it's oxygen during the explosion.",
"To add on to the other comments here, the oxidizing agent in gunpowder (potassium nitrate, commonly called saltpeter [thank you /u/CaptMercaptan], is used in traditional black powder) is what enables the explosion at all. The speed of a combustion reaction depends on the availability of heat, fuel (reducing agent) and oxygen (oxidizing agent). In most cases, like a bonfire, oxygen is the limiting reagent. The fire spreads slowly because the logs burn up all the oxygen right around them, and new oxygen only flows to the fire so fast. That's why you can blow on a fire to make it bigger, because you're helping more oxygen-rich air replace the oxygen-poor air that is right around the logs. Also, the logs can only burn on their outmost layers, because the inside of the log can't get any oxygen. In an explosion, the fuel and oxygen react with each other almost instantaneously. In order to do that, they have to be evenly mixed so that every bit of fuel has enough oxygen available to it. In a car engine, this is done by spraying a small amount of gas into a chamber with fresh air to make a mist of gas and air. When the sparkplug adds an ignition source, it explodes, and the huge surge in pressure makes your piston expand. In gunpower, this mixture of fuel and oxygen comes from the sulfur and charcoal (fuel) being mixed in the right ratio with the KNO_3, which can donate it's oxygen atoms. That lets the combustion happen fast enough to launch a bullet at the speed of sound.",
"They have oxygen in the cartridge...in the form of air and potassium nitrate. Essentially, the difference between something that burns when allowed to or explodes when allowed to is oxygen availability. Things that explode have their oxygen supplied by the chemicals directly in them while things that merely burn rely on room air to supply oxygen. Some chemical reactions can explode via other chemicals instead of oxygen.",
"Gunpowder hasn't been used for roughly a century, guns use \"propellant\" or \"smokeless powder\" these days. Modern smokeless powders consist of very large molecules made of Carbon, Hydrogen, Nitrogen, and Oxygen, plus a few other things added to improve performance. This molecule doesn't really like to be mangled into this configuration, so if you give it a chance it will recombine into a larger number of smaller, more stable molecules, expanding very rapidly in the process. Since the Oxygen is already inside the molecule, it doesn't need air.",
"The primer material (something highly sensitive like lead styphnate) will kick off the ignition of the powder within the cartridge. Then, as another poster mentioned, the oxidizing agent (potassium nitrate or nitrocullulose) within the cartridge powder will help with the rest of the burning process.",
"Explode and combust are different. Combusting takes oxygen. An explosion is the instant transition of substantial amounts of solid material into the gas phase which causes an exceptional volume increase.",
"As is with all explosives, it has its own supply of oxygen so it can theoretically burn in space (explode if it's in a confined space). The traditional oxidizer in gunpowder was potassium nitrate (KNO3) aka saltpeter",
"Like all explosives, it brings its own oxygen along for the ride. Many explosives have a fuel component, and an oxidizer component whether it's gunpowder, dynamite, or the fuel/air explosions in an internal combustion engine. Bullets for instance would work under water or in space and if an astronaut fired a gun while floating in space, they could actually use it as a form of propulsion. Rockets work on a similar principal, bringing the oxygen with them.",
"Because explosives do not need external oxygen to explode- the oxygen is built into the chemical itself. So why don't explosives just explode on their own- why do we need to \"detonate\" them? Think about explosives like a bunch of dominoes that have been stood on end such that one domino is next to two dominoes which are next to four dominoes and so on. Left alone- they will happily remain standing. But if we impart a small amount of energy (we knock over the first domino) it releases a whole lot more (the rest of the dominoes fall). In other words- when the dominoes are standing on end they have a lot of potential energy- but it's stable. As soon as we knock over one domino- the potential energy of that domino is converted to kinetic energy as it falls. That kinetic energy causes two dominoes to become unstable and fall over which in turn releases even more energy. The first domino releases 1 unit of energy- that causes 2 dominoes to fall releasing 2 units of energy. Those 2 dominoes cause 4 dominoes to fall which releases 4 units of energy. That causes 8 to fall, then 16, then 32, then 64, then 128 and so on. The progression is exponential- after just 16 reactions- we've released 65,000 times more energy than was released in the first reaction. Explosives work the same way- they have a lot of potential energy- but they're stable. As soon as we detonate them- a molecule collapses to a more stable state (i.e. the domino falls over) and releases energy which causes the molecules next to it to do the same thing and so on. This happens very quickly releasing a lot of energy."
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7dsw2l | How can a needle on a Vinyl record recreate music perfectly including the Audio highs and lows? | Technology | explainlikeimfive | {
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"Sounds are vibrations on the air. Highs are fast vibrations and lows are slow ones. The needle passes over ridges that cause it to vibrate fast and slow.",
"It can't. Not perfectly. I agree with you: how it can work at all with such great detail is short of a miracle. But it isn't without serious compromises: Bandwidth is 40Hz to 17kHz (exceptions are there of course, just so vinyl lovers dont feel the need to say how i'm wrong because some records do exist outside those limits..). Lower frequencies simply are too long to track with the amplitudes they need without the needle jumping out from the groove. We can also hit the next groove so the spacing would have to grow and there would not fit that many minutes on one side. Higher frequencies are too high and they can burn the voiceoil of the carving machine. We need serious cooling to go over 20kHz. 100kHz is the \"world record\" with liquid nitrogen cooled machine at full speed. Lowering to half speed carving means that the wow and flutter that are ALWAYS there, will become much harder to control and can rise up to be detectable. 16-17kHz is common lopass, 40Hz is hipass: that is our bandwidth. Doing this will give us at least some hope but we are not done yet. Not even close.. Next comes the fact that our surface noise is also a problem that makes the high frequencies VERY hard to reproduce. The noise that the needle makes when it scrapes along a surface would be too much. Since we have A: trouble with long waves taking up physical space and B: surface noise at highs.. we can attacks them both by using RIAA emphasis. What it means is that we employa filter that lowers all low frequencies (before we carve the master disc) and raises up all high frequencies. We emphasize. When we playback the disc, after the needle has picked up the vibrations, we put the same filter but in reverse: boost bass and lower the highs. This makes the surface noise drop below masking effect (louder sounds mask quieter ones) while also giving us physical room for our bass. And after this, we have to remember that the lower we go, the less and less channel separation we can have. In fact, everything below 250Hz is in increasing amounts mono information: both channels share the same signal. There is no stereo bass in any vinyl. And we are almost done.. We have to also limit the dynamic range after all that to about 70dB theoretical, around 50dB practical This means we can not pack as much energy into the track as we want, we can't peak limit the material to death.. This is where the \"vinyl is more natural\" comes from, it is just a different master, with the added flaws from your needle, RIAA filter and the inevitable slight distortion..",
"Sound is just vibrations in the air, picked up by little hair like fibers in your ear. If you've ever done the \"make your own record player\" experiment with a needle and a piece of paper rolled into a cone shape, you get the basic concept that the tiny bumps and grooves of the record, produce a reliable vibration when you run a needle over them, and when that vibration is amplified , even just via a piece of paper, it becomes recognizable to the human ear. Fudge I'm no expert but that's how I understand it."
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7dt1um | What are EMPs (electromagnetic pulses)? and how does an EMP jammer work? | Physics | explainlikeimfive | {
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"So imagine that people can communicate in a pond by making little ripples that go across the surface. Some use big, long ripples to go far, others with little short ripples that only go a short distance. Then, someone throws a big rock into the middle of the pond. Suddenly, there are so many ripples that no one can tell what messages are, and some people even get wet and don't want to send ripples anymore! That's a simple explanation for how EM works: the pond is the air, ripples are EM waves, people are the devices that send and received, and an EM pulse is that big rock.",
"They interupt capaciters and fry delicate electronics. Un-like Hollywood, they will not permanently destroy the power grid. Many high grade devices are grounded and electro-magnetically hardened to withstand such events. They happen quite often in nature. Have you ever lost power on a nice sun-shiney day?",
"It’s, as the name implies, a quick, high-energy pulse of electromagnetism. It typically occurs when nuclear explosions happen, and the way it damages electronics is via it’s strong charge, which essentially crisps electronics (similar in effect to when a charge plug is fried if a house is struck by lightning) When a nuclear detonation occurs in high altitude, the EMP caused is then called HEMP (High-altitude Electromagnetic Pulse). It has no negative effects on humans though. An EMP jammer works by sending out weak EMP’s in intervals, not destroying but disrupting electronics in it’s effective radius. Magnets have the same effect on electronics, and this is why you don’t let a magnet near your phone for example."
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7dt27p | how an organ transplant is performed? | ELI5: Take a kidney transplant as an example, I'm sure it has a ton of very small nerves/veins/whathaveyou sticking out of the kidney itself. Is the donor kidney connected to the body by "fusing" the nerves of the new organ to the person's body? How do they interconnect the veins seeing as they're super small to sew together? | Biology | explainlikeimfive | {
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"While that's true inside the kidney where the veins and arteries branch off, the kidney only really has 3 connections. The renal artery which connects to the abdominal aorta, renal vein which connects to the inferior vena cava and the ureter which connects to the bladder. The kidney itself has a lot of vessels but like the rest of the body, they all meet back up at one big artery or vein that branches to become arterioles/venules and capillaries. A lot of body components are like this, in that they only have one big entry point and exit point. Other parts might have a dual blood supply like the lungs, but only some places like the intestines have this really complicated network that branches out of the aorta, but even then, they unite back at larger arteries of which there are few."
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7dtana | Why does specific combinations of sounds (like tones in chords) sounds melodic and others not? | Sound* | Mathematics | explainlikeimfive | {
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"Because of math! When two frequencies are played at once, their waves combine to form a [composite wave]( URL_0 ). When those frequencies are a simple ratio (2:1, 3:2), the resulting wave is simpler. It sounds more pleasing, because it resolves, or returns to its starting point, sooner. Notice how a three note major chord is about as simple as a two note minor third, and how the minor chord takes twice as long to resolve as the major.",
"A lot also has to do with how were conditioned to hear. The adage “One Man’s Food...” We may squirm when we sit through a gamelan ensemble with their different norms for pitch as an Balinese gamelan ensemblist may be totally flummoxed by a Mozart piano concerto. Harmony as we now know it has been in a constant process of calibration for the better part of the last 1k years and the notes that we may deem “melodic” or “consonant” or euphonious may not have been the case a few hundred years back. By the same token, the norms in the future will breed different parameters for determining (if it can be called that) what is pleasing and what is not."
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7dtaqm | What is crypto-anarchism and what are it’s beliefs? | Technology | explainlikeimfive | {
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"Cryto-anarchism, is (I believe) something that has arisen mainly out of bitcoin. It's the idea that we can de-centralize our lives away from the state, and the elements of society that have control over us. Bitcoin is the best example. Bitcoins are an encrypted currency, so its incredibly difficult for the state/government to see where money is, who controls it, or where its going. It's the encryption part which makes bitcoin beyond the control of banks or government as we can make transactions in secret, and without the over site of a bank. This has given is the possibility of a new, free currency - one controlled by individuals instead of banks. This is the basis of anarchism - that we can live as individuals, free from control."
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7dtbay | why are there posts on Facebook that are just pictures but they are actually 30 second videos of that picture? | Other | explainlikeimfive | {
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"With videos you can select preffered audience and target demographics better. Also facebook has reported 135% increase on clicks on videos versus pics advertising webpages so it might be people thinking they are gaming the system and not understanding why they are clicked on more. If anyone has a better answer listen to them. I just did a quick google search",
"Facebook’s algorithm allegedly prioritizes video over other types of content, so if you post a video, it’s more likely to show up on people’s news feeds than if you post a text, link or image. People try to take advantage of this by posting a video of an image so they can get more likes and comments than they would if they just posted the image itself.",
"Thanks all! I just find it extremely annoying and I only noticed cause some videos have those stupid triangles floating across the image.",
"Is that why some of the videos now have flying paper airplane triangles for a filter? So there is actual movement? Edit: just noticed op posted the same response.... mah bad. Gotta leave it up and accept my shame.",
"Facebook sometimes run pre-roll ads on videos, some of the money from these ads can go to the creator. Also I believe Facebook algorithms prefer videos to photos and photos to text posts so more people will see it.",
"Adittionally, when you post a video, you can see how many people have watched it, but you can't see how many looked at your picture unless they liked it, which is a very small amount of the audience"
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7dthsb | If fire needs oxygen, where does the sun get oxygen if there's no oxygen in space? | Physics | explainlikeimfive | {
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"Its a common misconception that the sun is a ball of 'fire'. Its not at all. The sun's light is created by nuclear fusion in its core, a process which involves only hydrogen.",
"That's not fire. That's *plasma*, which is done by a process called *nuclear fusion*, where two atoms are fused together to make bigger atoms. This releases a ***LOT*** of energy, which ultimately (along with gravity) powers pretty much everything in the solar system.",
"People are correct that the sun isn't on fire, but I also wouldn't think of the sun as being \"in space\" any more than the earth is.",
"The sun isn't a ball of fire, it's more of a giant nuclear reactor. When a star is forming the pressure at the core causes it to be hot enough for nuclear fusion to occur, fusing hydrogen atoms into helium atoms. Nuclear fusion let's out a lot of energy, which makes it do the whole star thing"
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7dtktg | Uranium One | Other | explainlikeimfive | {
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"A company which mines 10% of America's Uranium was sold to a multinational mining company based in Russia. Due to the issues with Uranium the deal needed various government approval to go ahead. However before Uranium can be exported from the USA strict export requirements need to be met to stop the Uranium going to a state wishing to develop nuclear weapons, these requirements haven't changed, so the ore mined by the company is still most likely to be used in the USA. Russia is one of the worlds leading producers of Uranium and doesn't need to import it from any other country."
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7dtqsh | Do men’s and women’s hygiene products (shave gel, lotion, face wash) actually do different things for men or women, or is it a marketing thing? | Other | explainlikeimfive | {
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"Most of the ingredients are the same, though some manufacturers claim that their gendered products are tailored more towards the different areas that each gender tends to shave more. The main difference in ingredients is the scent. Fragrances and oils can be incredibly expensive, which could go towards explaining some of the difference in price. We know women place more emphasis on the fragrance of a product than men (some men being happy to purchase without smelling the product at all). At least when it comes to bathroom products, men and women discriminate on price differently. Men are more likely to take a cheaper product and see that product as equivalent. Women, on the other hand, are more likely to see a more expensive product as superior. Thus reducing price could be a good strategy for men's products but could actually lose you sales on women's.",
"Yes. Womens products tend to have more fragrances and moisturizers. Which is why they're more expensive. Of course, that doesn't mean you can't use em if you're a guy, or vice versa.",
"Men's skin differs from women's skin in a few distinct ways. Most notably is the fat content and hair texture along with different issues relating to aging (women lose their skin elasticity faster, for example, leading to earlier wrinkles). Various products *could* be designed with these things in mind, but there are plenty of men and women who use products \"for\" the other gender with no problems. It's marketing.",
"Men's shampoo comes in a black bottle, making it very manly. If you pay more for that, you are wasting your money.",
"They can be a little different. Men tend to have coarser hair and less smooth skin. Women tend to have longer hair, and are more likely to color, treat, curl, and blow dry their hair, all of which can damage it. Men don't worry about their skin so much because there will eventually be stubble no matter what they do. Women wear makeup, which can clog pores and irritate skin These all represent tangible differences. Men want to step out of the shower, run a comb through their short hair, and wash their face, and be done. Women want to spend more time and look nice. That said, a lot of it *is* marketing.",
"It's overwhelmingly marketing is the real distinction, but in many cases, the products are different, again because you want to market it, not because it makes a difference in its actual function. Women's stuff tends to have more scents and perfumes added as compared to mens products. But overall the actual function is identical, its just marketed as women's or men's because that sells better than unisex."
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7dtv85 | What happens when somebody drinks themselves to death by drinking too much alcohol in a short period of time? | Biology | explainlikeimfive | {
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"Essentially, alcohol works as a depressant for neural activity. The alcohol molecule binds to receptors on your neurons and reduces the overall neural activity in different parts of your brain. This usually begins on the outermost regions of the brain, your prefrontal cortex, which is in charge of your logical, rational thinking and moves inwards. People die when there is so much alcohol blocking neural receptors that the brain can no longer send signals to even maintain basic life functions such as breathing and heart rate."
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7dtvc7 | Is eating food off the ground in any way beneficial to your immune system? | I'm sure we all know the type: someone drops part of their sandwich on the ground, picks it up, eats it, then claims that they are, "strengthening their immune system" by deliberately exposing themselves to whatever was on the floor. Is there any truth to this? It seems to logically follow that giving your immune system targets to work on will keep it 'up tondate' and active. But do people who do this get sick less than people who don't? | Biology | explainlikeimfive | {
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"your immune system is like the borg. it is very adaptable. once it encounters one enemy, it'll be able to adapt to it and fight it off next time (assuming, that you survived the first encounter). being exposed to germs, bacteria, and viruses invoke your immune system. once your immune system is familiar with a certain pathogen, it can fight it. but your immune system needs to survive the exposure. there is a \"general strength\" of your immune system, the more pathogens it's familiar with, the stronger it's overall response (ie a higher white blood cell count, which is basically your soldiers) so someone who has lived in a very dirty environment will likely be much more able to fight off a new pathogen vs someone who's immune system has never been invoked (ie living in a clean room.). one way to artifically strengthen your immune system is by vaccines, which are basically the pathogen but in a much weakened state so the average immune system will have no problem fighting it.",
"I do believe this to be true. I live in a third world country and most children grow up in dirty environments. For example children of construction labour are left alone in a sand pit while their parents work and most of them roll around in the mud eat food swarming with flies and they have no pants on but those kids are completely fine and healthy as compared to these children that are brought up in rich backgrounds where even touching a dirty rag could trigger a dust allergy ."
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7du3i7 | Why are pianos unable to be completely in tune? | Physics | explainlikeimfive | {
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"Tones work together best if you can make a ratio of small numbers from the two frequencies, say 2/3 or 3/4. However, you cannot divide an octave into multiple equal steps and have any such ratios in there, because roots of 2 tend to be irrational. So for any instrument tuned to a particular key, semitones are not equal steps, but merely close to equal, with the intervals in the key's most common chords set to clean ratios. That means the instrument will be off if you play in another key, so for perfect results, you would need to re-tune it for another key. Since a piano has no preferred key (unless you count the all-whites C/a) and takes a lot of effort to tune, you need to make compromises which will keep it from being perfectly in tune for any given key.",
"When the frequencies of two notes are a simple ratio, the sound more pleasing. 2:1 is an octave, 3:2 is a perfect fifth, 4:3 is perfect fourth, etc. The musical scale is built this idea and tries to limit the notes on the scale to simple ratios. Basic music theory assumes the fifth note of the scale is at a 3:2 ratio with the root note. G is the fifth note of C major, so C and G form a perfect fifth. You see this in the circle of fifths, where going up 12 fifths is the same as going up 7 octaves. But this isn't quite true. It turns out that a fifth is just a smidge higher than the fifth note in the octave. At the end of the circle of fifths, you are about half a semitone off. This is known as the Pythagorean comma and can be easily heard. When tuning an instrument, especially one with the range of a piano, you have to make choices about what is in tune and what is not. In the Middle Ages, they had some keys where the fifths were exact and just avoided writing music in the other keys. A chord in a bad key was called a wolf chord because the binaural beats the out of tune chord made was reminiscent of a howling wolf. In modern music, the practice is to split the difference between all keys, so every fifth is very slightly out of tune."
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7dvc9e | When a baby is getting its first teeth, you're supposed to give them something to chew on to dull down the pain. How come when a teenager is growing in their wisdom teeth, they don't feel it until they start to disrupt the other teeth? | Source, 16 year old who was a "pain in the ass" according to my parents when I was getting my first teeth. But with my wisdom teeth starting to appear, I don't even notice them growing in. Why does it hurt so much for a baby to get their first teeth? | Other | explainlikeimfive | {
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"Don’t quote me on this, but you could flick a baby’s wrist and it would most likely hurt. A lot of stuff with them is due to their lack of pain tolerance. They simply can’t handle being uncomfortable. But that may not be completely right.",
"have you ever heard the phrase \"don't be a baby?\" babies are wimps."
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7dvd9n | Why is it so difficult to type (i.e. move your fingers quickly and precisely, or even at all) when your hands are very cold? | Biology | explainlikeimfive | {
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"When cold, your body reduces blood flow to extremities such as the fingers to conserve heat. This makes the nerves in the fingers less responsive, thus the numb feeling you get as well as the difficulty in making them move with the same agility as when warm.",
"There's a fluid in the joints known as synovial fluid that becomes more viscous (thicker) at lower temperatures. This thickness of the fluid contributes to the rigidity experienced when your hands are cold.",
"In the sodium-ion channels that control our muscles, the conductance increases steeply with temperature. Electrically speaking, warmer is better with \"wet\" electrical signals. The Canadian pianist Glenn Gould was famously concerned about his hands. He liked to soak his hands in hot water to warm them before he played",
"As a musician (specifically a strings player) cold hands are literally the devil. You get less blood flow, and your muscles become a lot less efficient. Your nerves (which are numb, because cold) refuse to send signals fast enough to do things that require a lot of dexterity (AKA texting or playing the bass)",
"Body pulls fluids to your core when you get cold, this lessens perfusion to your extremities. This lack of blood flow increases metabolic waste build up and lessens the available energy and oxygen. Also the lower temperatures inhibit some enzyme function..these multiple processes among others can continue to worsen until difficult movement becomes a complete inability for the affected areas to function",
"There are position or “angle” sensors in your joints. That’s how you know roughly where your hands are when your eyes are closed. Your brain depends on the feedback from those sensors to control your muscles. When cold, those sensors send delayed signals. The result is much smaller movements of your muscles. The effect is similar to what happens when you use a “speech jammer” app."
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7dvmhx | What causes the “burn” in muscles when working out? | Biology | explainlikeimfive | {
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"When you perform strenuous exercise, the movement of your muscles require more energy than can be provided by aerobic methods which use oxygen from your blood. Your body is then forced to produce energy by anaerobic methods (without oxygen). These processes end up producing a substance called lactic acid which causes your muscles to burn.",
"I haven't researched this in any way, so take what i write with a grain of salt. Basically, when you're working out, you basically slightly rip your muscles, and after resting, the places where it ripped regrow so you end up with more muscle than you started. This is also the reason you shouldn't work out too much and rest properly",
"The short-term pain that you feel while doing something over a short period of time like weightlifting or sprinting is caused by lactic acid. Inside each of your cells, there are mitochondria (yes, the powerhouses of the cell). Mitochondria produce a molecule called ATP (adenosine triphosphate) that provides energy for your cells to do things. ATP is produced by a process called \"cellular respiration\" which involves sugar (glucose) and oxygen. When you work out anaerobically (using up a lot of energy and oxygen in a short amount of time), the mitochondria can't complete the entire cycle of cellular respiration, so they go through \"fermentation\" instead- they produce a small amount of ATP and form the rest of the sugar into lactic acid. The lactic acid is released into your muscle cells and they become painful and fatigued, causing a burning-type sensation."
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7dvnjy | What are the main differences between popular opiates and why do people choose to do some over others for recreational purposes? | To clarify, I’m not looking to do any. I’ve known quite a few people in my life whom have gotten hooked on various opiates and today I was wondering, what makes them want to do fentanyl over heroin for example? I understand prices are a factor but as far as effects are concerned, what’s the difference between oxy, hydro, heroin, fentanyl, codeine, etc.? | Chemistry | explainlikeimfive | {
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"To my knowledge, as limited as it may be (opiates are not exactly my DOC) it mostly boils down to three things, two of which are closely related. Strength, availablity, and price. The latter being the related ones. Codeine is basically what i call the tier 1 opiate. It makes you feel nice and airy, puts you in a good spot, but it also has some side effects like itchiness, plus its usually pressed with APAP which is no good for the liver at high doses. So; codeine- plentiful, somewhat cheap, kinda weak, but still enjoyable. Hydrocodone is, for me, where we move up to tier 2. Now ive \"heard\" that hydrocodone is 6x as potent as codeine. Whether that number is accurate or not still gives credence to hydro being the second tier of opiates. Hydrocodone will criss cross you right the fuck up if you take enough, and *typically* without the itchiness (although this can usually be abated with a simple antihistamine.) So; hydrocodone- a little more expensive, much more enjoyable, stronger, less APAP in your system (ideally) Oxycodone. Tier 3. Now, unfortunately, this is where my knowledge runs thin. Ive only tried percocet once, and i know they were pressed, so i cant give you much, but to my understanding, this is the shit. This is the drug people take before they move up to heroin (if they feel so inclined). Hard to find, expensive as fuck, and very strong. NOW.... *fent*.... too dangerous, too risky, too unreliable for my taste. I mean, look, mere days ago an up and coming rapper DIES because of fent laced bars. This shit is DEADLY. I dont know what its like, because i havent tried it, and i dont plan to. Im sorry to you fentanyl fanboys, but i just cant get behind it. Ive known people that have OD'ed and i just cannot and will not toleralte this recent influx of fentanyl laced presses. It scares me, and it saddens me. Heroin is... well......heroin. Never done it, but i imagine it to be pure fucking bliss. Maybe one day, (hopefully not, maybe). We skip to tier 5 for our mistress, Lady H Anyway, thanks for reading and asking your good question, hope you all have a wonderful day! Sorry if this is a bit jumbled im very much in the zone right now. Peace!",
"There's little to no difference between the ways the opiates interact with your body. Though some batch of other of an illegal street drug might be cut with something else that has other noticeable effects - eg kerosene or cocaine - typically because they are cheaper. Delivery can matter - injection feels different than snorting or eating. Fentanyl is all the rage because it's super-potent and cheap. It's so potent you can overdose by getting the purified version on your finger and rubbing your eyes. It's so cheap because the Chinese are making it 'legally' - the Chinese government unofficially allows dedicated Fentanyl labs to produce product for export as long as they don't sell to other Chinese. (and bang-bang in the back of the head if they sell to Chinese - the Chinese do not fuck around with drug dealers) Beyond price it's just how the opiate is packaged, some things are easier than others. Oxy comes in a pill form and it's medically pure and known dosage so it's easy to think it's safe to start taking. Codeine can be bought by teens over the counter, so that's what they do. Heroin is 'bad' but cheap. Fentanyl is dangerous - your underground chemist really needs to know how dilution dosing works or he'll produce a batch that will kill people."
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7dvo07 | What does it mean that a city was founded by someone ? | I read often that some great ancient leader founded a city, e.g. the various Alexandria founded by A. the great. I am unsure what does that entails. For example: from where did the citizens come ? Is it just a matter of saying "this pre-existing conglomerate of abitations is henceforth to be known as Alexandria" ? Or was there an effort to relocate people more or less forcibly from the surrounding region ? I understand that thing may be different from case to case, so I am after some generic answer. | Other | explainlikeimfive | {
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"Generally a city is \"founded\" by whoever was in charge when it was decided there was going to be a city there. That can mean that Alexander the Great rolled up on some villages in a nice spot for a port and \"founded\" a city on top of them, or Peter the Great (lots of the Greats here) decided he wanted a new capital and forced thousands of people to die in a horrible swamp building it. Could also just be whoever lead the pilgrimage/wagon train/etc to a new spot and set up a town."
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7dvvd2 | Why is the wind stronger the higher you go? | For example there will be barely a breeze when on the ground but if you go up to the roof of a tall building you almost get blown over | Other | explainlikeimfive | {
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"It's due to increased friction at ground level compared to higher altitudes, where the air flow tipically does not encounter as many surfaces to collide with/brush against. Also, a cool case study is about how cities and buildings generally interfere with air flow inside and outside of them and, as such, create micro-climates and channel these flows."
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7dvxs6 | Why do some alcoholics suffer life threatening withdrawl symptoms when others with the same drinking habits don't when they quit? | Biology | explainlikeimfive | {
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"Everyone is effect differently by alcohol due to age, weight, genetics, etc. With chronic alcohol abuse, parts of the nervous system adapt to functioning in the presence of alcohol (aka. tolerance). When the nerves are highly adapted to alcohol, removing it can drastically alter the function of that system, leading so side effects depending on what nerves adapted and how much they adapted. The damage that quick alcohol withdrawal varies a lot and can be permanent, for example parts of the brain can die due to a sudden increase in intracellular calcium (not ELI5 but I think its an interesting mechanism.",
"Dependence and tolerance are completely different from an addiction. They may often go hand in hand but they are separate entities. There might be an addiction with or without dependence and tolerance.",
"You know how a new sliding window slides really well for (x) amount of time? Then maybe it starts to get a little stuck, so you spray some WD 40 or whatever, and now your window slides easily, and you're like \"sweet, I didn't have to deal with the real problem of putting in new windows, because these are good as new!\" Then after a few months, that window is sticking again so you throw some more WD 40 on it and it works again, and you're like \"great! Well hopefully this doesnt become a more frequent thing I have to continuously do in order for my window to function correctly!\" And then the next month you have to WD 40 it again, then in two weeks, then a week, few days, etc. The window is now reliant on the WD 40 to perform the simple task of opening, but now it even sticks sometimes even after using a whole can. Let's say it was a wood window... the reason it worked pre-WD 40 is because it was treated. After introducing the WD 40 to the wood, the wood started to dry out- what have you - even more/faster. Or we could say that the WD 40 reacted to whatever the window was treated with, so the window now no longer functions the way it did in the beginning, and it is not physically possible for it to complete the task of opening. However, if we take these broken windows, and sand them down/re-seal them, the WD 40 is no longer needed, and contingent on daily maintenance, the windows will never need it again. That was a really stupid analogy, but it breaks down to how alcohol and your brain work. This coming from an alcoholic who kept such an astronomically high BAC that when I tried to go in to my third residential treatment sober, at 16 hours without a drink or drug, was withdrawling to the point of hallucination and severe DT's, only to find out I was still at a .33 BAC... four times the legal limit.",
"From what I know, at a certain point the liver just becomes good at only one thing: getting alcohol out of your system. Your liver cell’s smooth endoplasmic reticulum grows to handle more and more alcohol, which makes the liver “harden”. Im not sure enough about this information to draw any conclusions, so do with it what you want. Please correct me if I’m wrong!",
"There are different degrees of alcoholism. You have functional alcoholics, who can control their drinking enough to live a normal-ish, if unhappy life. They are taking a lot of risks, losing their job, their family, getting a DUI, but they haven't completely fallen apart. They can usually go without and not suffer serious withdrawal. Then you have people who just want to be wasted all the time. They wake up and drink as much as they can until they run out. They can develop very high tolerances and can still be coherent at levels of intoxication that would render normal people unconscious. these are the kind of people who can die from withdrawal symptoms."
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7dvxz4 | Why do sloths move slower than people and other animals? | Biology | explainlikeimfive | {
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"text": [
"Because that is the evolutionary strategy they adapted to. Because they move so slowly, they are easily hidden from predators that hunt by sight. Many of those predators key in on movement, so if you don't move, you aren't spotted. Additionally, moving slowly expends very little energy. That means you can actually survive on a very energy-poor diet, that other animals wouldn't be able to survive on. That means you don't actually have competition for the food you are eating. They've found a niche and they adapted to it."
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7dw9p0 | What does binge drinking do to your body compared to more regular drinking of lesser amounts? | Biology | explainlikeimfive | {
"a_id": [
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"text": [
"Drinking alcohol is effectively a way to poison your System. Luckily, your body has developed detox strategies that kick in as soon as alcohol is consumed. Alcohol can be processed in your liver to be broken down into less toxic substances by special enzymes. Now, if you drink certain amounts of alcohol, you overwhelm this detox system (basically anytime you start feeling buzzed, is when there is more alcohol in your body than can be metabolized). If it's 'moderate', your body will have to recover, but also learns from that experience by producing more of these enzymes (which is referred to commonly as 'building up a tolerance'). Note that you poisoned your body nonetheless, just not in a way that is entirely destructive or lethal. You just did it enough to maybe disrupt some nerve signals and hence feel less inhibited or less balanced, etc. If you binge drink, you purposely flood your system with so much alcohol that it becomes nearly impossible for your cells to detox before real damage is done. In order to avoid getting more poisoned, your body makes you vomit, so that no more alcohol can travel from your stomach to your intestines and be absorbed. However, at that point you have already disrupted proper signaling in your body, meaning you may pass out, piss yourself, or even stop breathing altogether.",
"Binge drinking causes a higher amount of alcohol in your body than regular, lesser amounts. This can overwhelm the primary ways your body has to breakdown alcohol. The most well known symptom of alcohol abuse is liver damage. The root of most alcohol related liver damage is due to the body finding other ways to break down alcohol that have harmful effects (creating fat around the liver or reactive by products). With more regular drinking, even if at the same amount during each night spent drinking, the body adapts its breakdown of alcohol (by changing enzymes/other molecules amounts) ultimately being able to break down more alcohol faster without using the bad breakdown paths."
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7dwdb4 | How did David Bowies eyes, one dilated, affect his visual perception? | Biology | explainlikeimfive | {
"a_id": [
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"text": [
"A friend with the same issue said the only time they notice is when it's really bright, really dark, or when moving between different light levels."
],
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3
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7dwgon | do babies really need to drink warm milk or is it more like a society myth? | Biology | explainlikeimfive | {
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"text": [
"Well, babies tend to stick with drinking what they know. Usually, it's that sweet, warm milk from mommy's boobs. So they prefer warm drinks over cold ones. When older, and able to drink cow milk, they might as well drink cold milk, but they might stick to warm just because it's what they know. When babies are fed formula, the water to mix with the powder has to be warm to dissolve it. Plus, that shit gets nasty when cold Source: am a dad, at this moment bottlefeeding my one year old his warm night bottle of formula.",
"They probably won't die, but they then have to warm up the cold milk internally, which takes up more energy; and various proteins only work at certain temperatures making that necessary. Babies also don't thermo regulate that well to begin with so they may get cold which has its own problems. It's the same idea for adult who go winter camping, where you should go pee before going to sleep at night, keeps you warmer.",
"When they breastfeed they are drinking milk that is at body temp of the mother. So when we feed them from a bottle we heat it as that is what they are naturally inclined to drink and they will often refuse to drink milk that is cold. Additionally formula will not mix well into cold water."
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7dwgxf | Why do limbs get all fuzzy feeling when you lay on them or leave them in a weird position? | Biology | explainlikeimfive | {
"a_id": [
"dq0ue62",
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"text": [
"Actually it's not blood supply it's pressure on your nerves which causes them to report odd sensation. Our main arterial supplies are deep inside muscle and much less susceptible to crush injury than we think.",
"It's called **parasthesia.** It occurs when nerves are compressed which can interfere with its functioning, either preventing it from sending signals or causing it to send signals for no reason. Your brain get this information (or lack thereof) and interprets it as a fuzzy, tingling, or pricking sensation."
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7dwm4j | why are credit/debit card authorizations painfully slow? | Technology | explainlikeimfive | {
"a_id": [
"dq0wiha"
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"text": [
"From the question I can only think you are reasonably young, as it's lightspeed quick to me, an old fart. The vendor has a computer that has to connect down a phone line/ internet connection to a bank computer that has to verify the details line up with you, the customer, and that you have the funds, and then transfer those funds to the vendor. It has to do all this for thousands of people at the same time, all securely and without errors. I think it's a minor miracle it's as fast as it is."
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8
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7dwyv4 | What would happen to an aeroplane trying to land while there was an earthquake? Would it have to wait until the earthquake has finished to land? Or would it land anyway? | Other | explainlikeimfive | {
"a_id": [
"dq0ws1l"
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"text": [
"Unless it was an emergency landing, the pilot would have wait. It would have to wait to make sure the airport can handle landings, and to make sure there were no after-shocks. It may even have to fly to another airport depending on how strong the quake was and how much damage occurred to the airport/runway."
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4
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7dx9ww | why do female praying mantises eat their mates? | Biology | explainlikeimfive | {
"a_id": [
"dq0zto1",
"dq14380"
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"text": [
"There are two different strategies for reproduction: have very few offspring and invest in them a lot (elephant, human, rhino, gorilla, etc.), or have numerous kids and don't invest in them very much (most reptiles, insects). Neither strategy is objectively \"better\", they both have their definite benefits in different context. If the Praying mantis mom and dad are not gonna form a pair bond and invest in the \"children\", what's the purpose of the father if he's already done his part of the reproduction deal? Let the female absorb his energy.",
"This is actually a misconception. Scientists once found that female praying mantises would eat their mates in an experiment, but there was a significant flaw in the study - those praying mantises were all starving at the time they were introduced. In nature, they will *sometimes* eat their mates, but only when they're hungry."
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25,
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7dxkh3 | How does the body stay warm? | Biology | explainlikeimfive | {
"a_id": [
"dq11nxy"
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"text": [
"The body has loads of different mechanisms to keep heat stable eg. Vasoconstriction is when the blood vessels near the skin become narrower and let let blood pass through, this reduces the amount of heat that’s lost from the surface of the skin. Muscles also shiver, rapidly contracting and relaxing. This requires more respiration in cells to produce energy, and a by-product of respiration is heat."
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7dxpig | Why does biting aluminum foil feel unpleasant but biting on a metal spoon or fork doesn't? | Chemistry | explainlikeimfive | {
"a_id": [
"dq1d00l"
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"text": [
"Aluminum foil is just the processed and pressed, oxidized element; where as steel is a stable alloy, and other flatware materials, like silver, are much less reactive. Due to the Al being raw-ish, when you bite down the foil, your saliva, and your teeth create a mini battery. You may get the same sensation with really cheap or plated silverware, especially if you have metal fillings."
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3
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7dxqjk | Around what prevalence rate would it be appropriate to consider a disorder "rare"? | Biology | explainlikeimfive | {
"a_id": [
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"text": [
"URL_0 URL_1 A disease or disorder is defined as rare in Europe when it affects fewer than 1 in 2000. A disease or disorder is defined as rare in the USA when it affects fewer than 200,000 Americans at any given time or about 1 in 1,500 people. In Japan, the legal definition of a rare disease is one that affects fewer than 50,000 patients in Japan, or about 1 in 2,500 people. The definitions used in the medical literature and by national health plans are similarly divided, with definitions ranging from 1/1,000 to 1/200,000."
],
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3
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[
"https://rarediseases.info.nih.gov/files/rare_diseases_faqs.pdf",
"https://en.wikipedia.org/wiki/Rare_disease"
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7dxudz | Why is cat5 wire used for data? Could regular 18/2 wire do the same thing? | Since data is just 1s and 0s can you use any kind of wire transmit data? | Technology | explainlikeimfive | {
"a_id": [
"dq1414e",
"dq147br"
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"text": [
"When you start transmitting data at radio frequency (CAT5 supports up to to 100MHz), copper is not just copper and the electrical characteristics of the cable start to limit how much data you can transmit and how far it can propogate. CAT5 is nifty because it has four twisted pairs of conductors (which minimizes some of the effects of long cabling) and it's standard therefore cheap to rely on. So no, you can't just use 18/2 wire. You could if you twisted 8 conductors into pairs, at which point you have a CAT5 cable.",
"It would work (TCP/IP has been successfully used across barbed wire before), but for maximum efficiency CAT5E uses the wire pairs and the twists that each pair have around the individual four pair to help reduce the possibility of crosstalk."
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7dxxdq | why does a 1080p movie, on a 1080p screen, have black horizontal bars at the top and bottom? | Technology | explainlikeimfive | {
"a_id": [
"dq14ead",
"dq14dmy",
"dq15smw"
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"text": [
"1080p is the resolution. The black bars are all about aspect ratio. The screen size ratio of a cinema screen is different from your tv/monitor. To avoid warping the image, they need to add the black bars in order to achieve that same ration on your screen.",
"Unlike TV, which is almost always filmed at 16:9 these days, movies are often created in differing aspect ratio. The actual choice of aspect ratio is one of the artistic decisions made during the production of the movie. If you want to get rid of black bars you can either zoom in the image, cutting off parts, or you can stretch it out & distort the image. Neither of these are seen as idea.",
"The don't add black bars. The movie was edited into a wider aspect ratio than your TV. So when it's shown.....there just isn't any content for that area of your TV screen. Not all movies have the same aspect ratio, like TV shows do. In fact, if you go to the cinema and pay attention between the previews and the feature presentation, you'll actually see curtains on either side of the screen either move in or move out to accommodate the aspect of the content they are currently showing."
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7dycg2 | how does general anesthesia make a person fall asleep? | I want to know the science behind it like does it slow the heart and mind down causing you to sleep and what happens in the body during anesthesia? | Biology | explainlikeimfive | {
"a_id": [
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"text": [
"Your not really asleep. It's more of a loss of consciousness then the regular cycle you go through at night. While we have a decent idea of how anesthesia works the specifics are still a bit of a mystery. Partly this has to do with our lack of understanding on the mind in general."
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7dyfqz | What does our brain experience when we try to understand really large numbers or the size of the universe, and what causes this limitation? | I’ve always loved watching science videos but was always curious what it really means when concepts are “too big or complicated for our brains to handle.” What limits our brain physically or psychologically, and what happens, if anything, when we try to understand these ideas? | Biology | explainlikeimfive | {
"a_id": [
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"text": [
"We can only really imagine things that we have a frame of reference for. Without that frame of reference, we've got no idea where to start with our abstract thought. For example, I could ask you to think up/invent a brand new animal. Chances are, you'd think up something vaguely similar to an already existing animal that you know about. \"Dog with six legs instead of four\" for example. Because of that limitation, when we're talking about the size of the universe, it's just incredibly difficult for even the most abstract thinkers to comprehend. I mean, the Earth is massive, right? It's about 4,000 miles in circumference. But the Sun is 432,000 miles in circumference. So you can kind of get a frame of reference here by thinking \"Okay, the sun is about 100 times bigger than the Earth\". The Sun is about 93,000,000 miles away from the Earth, so that's like putting 25 suns in between us. Well, what about the solar system? That's about 7,440,000,000 miles across. That's about 17,000 suns across. And the Milky Way galaxy? Well, that's about 100,000 light years across. 1 light year is about 5,880,000,000,000 miles, so multiply that by 100,000 and you've got 5,880,000,000,000,000 miles. So our Milky Way galaxy is about 13,611,111,111 suns across. And we're a relatively small galaxy. And the universe entirely? Well, that's about 46,500,000,000 light years across. Around 27,432,000,000,000,000,000,000 miles across, which is somewhere in the range of 6,350,000,000,000,000 suns across. It's hard enough to really comprehend just the size of our own Earth. So 6 quadrillion suns? If a grain of rice were to represent the size of the sun, you would need a pile of rice that was 914 cubic feet (about 10x the size of an average house) to represent how many suns that would be.",
"ELI5 version - Imagine you are a child who has never seen the outside. You don't even know it is there. Suddenly, someone starts talking about the outside but you can't even imagine such a place exists because you have never seen or heard about it. Your world just can not accept that there is more than the house you have never left. Another good example was in The Matrix when it was explained that so many people can not be \"unplugged\" because the sheer idea that the life they were living was fake would not be accepted by their brains. Same concept. It's hard to grasp things you can't see."
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7dyiff | If you stay up long enough, why do you stop feeling tired? | Whenever I'm up late playing games or just doing pretty much anything else, around 1-3 am I start feeling tired and soon to the point of barely staying awake. Sometimes I manage to stay awake but I stop feeling tired. Also this may not be the healthiest thing but I pulled an all nighter last night but don't really feel any different the next day. | Biology | explainlikeimfive | {
"a_id": [
"dq1a7xn"
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"text": [
"Basically your body knows what time it is. It's tired and it wants rest. But you refuse, and while your body knows what time it is the thing also reacts to what you are doing. So you screw up the internal clock and your body is like, \"okay, I'm not getting any sleep, must be time to get up.\" So your body tries to go into awake mode and while you won't feel as energetic as you would have had you slept, it's your body trying to wake up and do the things it normally does when the sun is up. That's the ELI5 version. :D"
],
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4
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7dykat | How do our bodies know when to make blood and when to stop making blood? | I'm not sure if I'm being silly when I thought about this but if a wound was left to bleed, how does our body know to recreate lost blood, is it doing this 24/7? How long does one "batch" of blood last and how does our body calculate if it needs more (or less?) Are there or has there been cases of essentially drowning internally of blood production? | Biology | explainlikeimfive | {
"a_id": [
"dq19d8n"
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"text": [
"So erythropoietin (EPO) is a hormone produced by the kidneys, when the body is lacking oxygen in the blood (when someone is at super high altitudes or losing blood at such high levels that there is low numbers of red blood cells carrying oxygen). However, there is always constant low amount of EPO being produced to replenish the dying old red blood cells with new red blood cells from bone marrow."
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7dynou | Why do we get those weird wrinkles/lines on our faces or body after sleeping? | Biology | explainlikeimfive | {
"a_id": [
"dq1aaz5"
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"text": [
"The skin was pressed against a fold or wrinkle of fabric which created a lump, which in turn caused a temporary indentation in your skin. This happens after sleeping because you don't move for a long time, but could just as easily occur while awake if you didn't move."
],
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5
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7dyr64 | What does the "Night Shift" feature on an iPhone actually do? What are it's benefits? | Technology | explainlikeimfive | {
"a_id": [
"dq1axyb"
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"text": [
"it basically reduces the amount of blue light that's displayed by the display when the ambient lighting is low. blue light can interrupt sleep patterns and is generally bad for your eyes in low light."
],
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11
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7dytgy | What is the feeling of semi-weakness people sometimes get when they are cold? | Biology | explainlikeimfive | {
"a_id": [
"dq1it0t"
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"text": [
"At cold temperatures, oxygen is more tightly bound to the hemoglobin in blood and does not release as easily. This slower rate of release leads to a lower amount of oxygen available to your muscles, making contraction more difficult. Also when we are cold, blood is conserved around our vital organs to ensure our body continues to function, but this part may not be relevant."
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7dyw7m | How do the people that transcribe court proceedings live do it? Looks like they have a minimal typewriter. | Other | explainlikeimfive | {
"a_id": [
"dq1bf05"
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"text": [
"They use a Stenotype machine which allows for extremely rapid typing. Multiple keys are pressed at the same time to spell out whole syllables, words, and phrases with a single hand motion. URL_0"
],
"score": [
5
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"text_urls": [
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"https://en.wikipedia.org/wiki/Stenotype"
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7dyy65 | How does modern recycling work? How are containers filled with food handled? What percentage of recyclables are actually thrown out? | Technology | explainlikeimfive | {
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"text": [
"This really depends where you are. Most food is collected, piled, composted and reused as fertilizer. As for recyclables, how much is thrown out depends on how good the sorting system is, also how much non-recyclables are put in initially. If you are really really strict on what goes in then you can recycle almost all of it, if not well... I'm not sure you want to share where you are from, but you could search how your particular municipality deals with waste.",
"According to my friend that works in that industry (in the USA here) food containers are thrown in with the normal trash because they can't be recycled. (We were told this year it's finally ok to recycle pizza boxes). the other stuff is sorted, some by hand, and bailed like hay and then sold to other countries that do the actual recycling. The USA doesn't have the facilities or the funding to do much of it. Recently less and less is being bought for various reasons. Most of the recycling in the USA is sold to China. E-waste is similar, but more of a human horror story in developing nations. The collection, sorting and bailing are all handled according to municipal and state law along with various county and city regulations/contracts. Business is business all around though.",
"Here in Denmark: Food is not allowed on recycling center. That goes in the household trash. All household trash is burned to generate heat. This is done in special powerplant that uses high heat, filters and other techniques to keep pollution at a minimum. The list of things that burns well includes many things you should never put on a bon-fire, like EPS (polystyrene cups, boxes etc).",
"In Finland a recycling engineer once said to me on a plant tour that returning your plastic or glass soda bottles to the store is Ok, but other plastic and glass packing materals are useless to recycle. There's always the one idiot who throws those in with food still in them, so they kept losing batch after another, making useless gunk. Now they just dump it all in one spot, hoping future generations can do something about it. I don't know if metal recycling has same problems. My quess is that metals are more expensive and worth some extra processing."
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7dz954 | How does an ISP plug into the internet? | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"The ISPs are the hubs that form the internet backbone and they connect to each other, and by extension the various servers and computers that connect to the ISPs and you have the internet. As to who runs the infrastructure, that varies by country but in general it is the ISPs. Individuals cannot directly tap into the backbone infrastructure. If a country has a strained relationship with others they often do not connect to the larger global internet, or highly limit how they connect. See China and what is called \"The Great Firewall\" or how North Korea has what is effectively a national Intranet rather than a real internet connection."
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7dztj6 | How do constellations stay the same in such a violent place like our galaxy? | Physics | explainlikeimfive | {
"a_id": [
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"text": [
"They don't. But you'll never live long enough to see them change. The stars are moving relative to each other, but it's happening so slowly it's very hard to notice. In the 17th Century, Edmund Halley noticed that the then current position of some stars did not match the ancient Greek recorded position of these stars- a span of about 1600 years. URL_0 also, Polaris was not always \"the north star\", at one time the star Thuban was the pole star. At other times there is no star exactly at the pole at all.",
"The stars are moving. They are such great distance from us that the movement takes thousands of years to be apparent. There are some nearby stars that move a little quicker. Barnard's Star is one of our nearest neighbors, about 6 light years away. Over the course of a lifetime it will move about half a moon diameter in distance."
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7dzvab | How does an animal adapt its skin colour to its environment? | Biology | explainlikeimfive | {
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"It's not genes turn the animal white or camoflauge. It's about who gets left over when the environmental conditions change. White Polar bears are the ones that survived same for lions and tigers. Imagine eating all m & ms except the red ones, then you will have a pile of red M & Ms",
"Much like u/fourtwentydude said you are viewing evolution and adaptation incorrectly. It is not the individual organisms doing any particular thing to change their colors (in this context). Its that fact that over thousands of years the animals that propagated and passed on their genes that gave them a higher chance of survival. aka a polar bear that is born bright red will likely not survive and be able to pass on those genes and eventually it would die out (this is a very simple example). While others that are lighter and possibly blend in more are able to survive, hunt and propagate more effectively which leads to those traits being passed down."
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7dzxcs | If any distance can be halved, at what point do you stop touching something? | Mathematics | explainlikeimfive | {
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"You're never touching anything - you are just as close as possible to it. The sensation you feel is effectively the force of the atoms \"pushing back\" against your fingers (and your fingers' atoms \"pushing back\" against the atoms in whatever you are touching). Think of it a bit like how two magnets push against each other, but much much stronger.",
"Planck length, the smallest possible measurement in the universe before the laws of physics break down.",
"Uh... if you're taking your finger off something, then the distance will increase, halving is a decrease. Also, from a physics standpoint you never actually touch anything... Aside from those, you're describing a form of one of Zeno's Paradox. Ultimately the solution is the fact that in the limit, 0.99999.... is equal to 1."
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7e0crv | They say 70% of taste is smell. When we smell, let's say a public restroom, are we actually inhaling and "tasting" particles? | Biology | explainlikeimfive | {
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"What is meant by this maxim is that, contrary to what you might believe, the taste buds on your tongue don't do much actual tasting. They can detect if what you're eating is sweet, salty, bitter, sour or \"umami\" (a word which describes the savoury \"meaty\" taste of a good stock, the taste that's enhanced by monosodium glutamate). Your taste buds can't do much else. Everything else associated with taste is in fact detected by the nose, using the same receptors as those which detect smell. This is why if you have a really heavy cold everything tastes bland: the mucus in the nose prevents the smell receptors from working. The tongue still works, though, so you can still tell if something (like the pills you're taking to try to stop your head hurting) tastes bitter. When you walk into a smelly environment like a badly-cleaned public restroom, you are of course detecting the various complex molecules that are floating around in the air. You breathe in, the nose detects these molecules and sends signals to the brain: that's \"smell\". When you eat, the food in your mouth releases various molecules that find their way into your nose where they trigger those same receptors. So it's not so much that you're tasting the molecules that you're inhaling; more that you're smelling your food as you eat it.",
"Yes. Neurologists have come up with some good words to help describe your senses. \"Taste\" is what's done with your tongue and other taste receptors in your head, which are attached to your brain via several cranial nerves. \"Smell\" is what is done with the receptors in your nose that are an extension of the olfactory bulb and the signals are processed there directly. \"Flavour\" is the sensation that arises in your mind when you combine smell and taste, and it's aided by a few other types of inputs around your head that detect things like heat, acidity, texture, etc. As a congenital anosmic people are really confused when I can't smell a fart, but I can tell from across the house that you're cooking. The difference is that I can't taste hydrogen sulfide on the air, but many things that you cook CAN be tasted. The \"smell\" of most cooking to me is best described as \"hot salt\". Another example, I can often tell I'm at a gas station because of the \"smell\" of fuel. It's sweet, by the way. Gross poison sweet, but sweet. There's a lot of stuff like that I'm sure people don't realize. I also constantly get the question \"but can you taste things if you can't smell?\" And yes, actually from what I can tell there isn't a lot of difference. Smell is apparently more nuanced, and it's much more sensitive, but you can taste things in the air.",
"So I have what I thought is a \"lack of a sense of smell\" or one of the worst of anyone I know. I don't know what things smell like. When people say they smell the fresh cut grass or the smell of rain in the air or things of that nature, I don't understand. I've never been able to identify any food by the smell. I've had friends walk into public bathrooms and almost run out vomiting and I could walking and sit on the toilet for 10 minutes without issues... When I tell people I have zero sense of smell they tell me \"that's not possible because you would not be able to taste food\" I can taste food and identify it by taste, but there's not a chance I could identify it by smell. Is there something wrong with me?"
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7e0mli | How do earphones produce adequate bass despite their size? | Technology | explainlikeimfive | {
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"Proximity to your ear. The volume of air displaced by a large subwoofer is large, but it is many feet / several hundreds of feet away from your ear. If you are too close to something of this size, you will be doing damage to your ears because the volume of sound waves hitting your eardrum is too large. Similarly, small earbuds produce a bass sound with a very tiny volume, but that earbud is mere millimeters away from your eardrum. Change that even to a few centimeters and the bass sound waves diffuse too quickly for them to affect your eardrum.",
"It's actually easier for an earphone to produce bass than for a loudspeaker to. The reason is that the volume of a speaker drops off by the square of it's distance. In short, this means moving twice as far, results in 1/4 of the sound reaching you. While bass frequencies travel farther through the air than treble does, it requires much more power to produce them due to the physical excursion required from a driver. The only way to produce powerful bass in a loud speaker is by moving air. This could be a very large speaker that moves just a little bit, or a smaller speaker that moves in and out very far. Either way it takes a LOT of power to do this and in order for the user to hear it, the speakers enclosure, and placement in the room is critical. However on a headphone, the speaker is very close to the ear, sometimes even inside of the ear canal. And since it is possible to form a sealed enclosure with the speaker on one end, and the ear drum on the other, powerful bass can be produced with very little excursion (very little air needing to move) and with very low power requirements. Larger, over the ear, headphones often have driver sizes of 50mm or more, which is a lot of surface area moving very close to the ear canal, and powerful bass can be produced. The other thing to consider is the tonal balance of the headphone speaker between bass and treble. If you had a perfectly balanced frequency response, and changed the speakers enclosure slightly to reduce the level of treble frequencies, the perception of the user is that the bass frequencies were made louder. They would simply increase the volume control to compensate, resulting in louder bass."
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7e0mxx | Why are anti viral drugs only used for life threatening viruses? | Biology | explainlikeimfive | {
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"I'm a medic on an ambulance and this is purely anecdotal. But we deal with a huge amount of people with unknown diseases on some of their worst bloodiest days of their lives while under great stress and bouncing around in the back of a truck. Accidental needle sticks happen. Hearing the story of a medic who got an accidental needle stick from an hiv and hep c patient and the prophylactic drug effects on that guy sounded worse to me than living with those diseases. Within 12 hours of taking the first round of drugs he was screaming in pain because he felt like his joints were on fire. All of his joints. Even the seams in his skull and face. The guy was out of work after that for about 2 months to recover from that incident. From what I heard, he's still testing negative to both diseases, but those drugs are not to be taken lightly.",
"But they aren’t. Millions of acyclovir doses are used as prophylaxis to prevent herpes (painful but not life threatening) outbreaks or to shorten an existing outbreak. Tamiflu can be used to shorten a legitimate influenza episode (which can be life threatening surely but the indication is for any old flu episode). Maybe tell us the source of your specific question and we can answer Best we can?",
"Most viral infection are quickly dealt with by your immune system and so antivirals aren’t necessary. They’re also more expensive than antibiotics and so cannot be used as sparingly"
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7e0xw6 | Why does being outside in the cold cause a runny nose/other cold like symptoms? I was under the impression that cold weather causing a cold was a myth. | Biology | explainlikeimfive | {
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"A runny nose due to the cold is not the same as having a cold... The purpose of your nose is to warm and humidify and warm I coming air before it gets to your lungs. When it's cold, your nose ramps up mucus production because cold air is dry and it needs more to achieve that goal."
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7e13fz | What would the real world consequences of things the privates did in Full Metal Jacket be? (spoilers) | Other | explainlikeimfive | {
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"In that time period, absolutely nothing would be done about it. Hazing was a normal activity, and it was often quite severe. The point being to either scare the person into quitting, or beating him until he learned that he has to do better to avoid getting beaten more. The scenes you describe are totally accurate to the military of the 80's and before. Maybe even a little into the 90's. In today's military (USA), this practice is strictly forbidden. Any unit that did that would be immediately punished, up to and including (for multiple violations) dishonorable discharges or criminal charges. The victim would be moved to the on-base hospital until they recovered, and then would be cycled in with a different training unit that was about where he left off (give or take a week). Any Drill Sergeant/Instructor found to be permitting this behavior would be immediately relieved of his duties, would likely be demoted if not immediately discharged. No Drill Sergeant/Instructor would risk his entire career to beat one private into shape. It is a Drill Sergeant/Instructor's explicit duty, first and foremost, to consider the safety of every one of his would-be soldiers. They are no longer allowed to touch you, hit you, choke you, etc. The worst they can do to you *now* is scream and order you to exercise (which now have mandatory limits, so no more \"running until you puke\" or being woken up at 0200 to do pushups)."
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7e16gn | Why do we get bored? What is the psychological reasoning behind it? | Biology | explainlikeimfive | {
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"There is a VSauce video on Youtube that I believe is titled this exact question. Check it out, it's really good. URL_0"
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7e16q0 | Is there such a thing as conscious and subconscious brain? | If yes, please also highlight the basic function of either. | Biology | explainlikeimfive | {
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"Yes. The conscious brain is what you do when you're actively reading, writing, meditating, focusing on something, etc. The subconscious brain can be a bit morass. The classic example of this is when you're doing a mundane task but not actually focusing in it, like driving. Ever drive from point a to point b and not remember the actual drive? It can be said it's because the subconscious mind is responsible for doing the driving while your conscious brain wanders."
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7e1at2 | How do music/video editing programs isolate vocals, frequency, pitch, etc.? | Technology | explainlikeimfive | {
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"It’s pretty complex but I think what you don’t understand is that the editing softwares are not meant to isolate anything, they’re meant to take the isolated vocals and turn them into a final product. So with each recording you can edit its pitch and frequencies and do whatever other mixing you wish to do, and then you mix everything together so it’s one big composition. Basically like a puzzle.",
"I don't think there's a good ELI5 answer to this, but basically it's math. Sound is a waveform, you can add multiple sounds together to get a new one. It's just like adding two numbers together. Basically if you want to isolate vocals you just do the opposite. You look for parts of the signal that look like vocals and subtract them out. The hard part is finding vocals. Typically programs will look for frequencies that correspond to vocals to find them but there are many tricks that involve very advanced mathematical techniques."
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7e1bvi | Why is it that almost all microsoft pc's start their drives with C? Why not A? | Technology | explainlikeimfive | {
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"It's an older convention for computers. Drives A and B are dedicated for Floppy Disc Drives, used for installation of programs on to the hard drive C As the systems evolved, B became a backup to A, sometimes using the older, larger discs, and eventually they were removed entirely, leaving A and C. B was left behind in case. In the advent of larger programs, especially as programs started taking huge stacks of discs, the installations started to move to CD Drives (which defaulted to D), and the Floppy Drives began to be removed entirely. You are probably wondering why we don't move the C drive to become the A drive in new systems... Too many programs actually wrote in references to the C drive *specifically* as the installation drive, and changing it would have caused too many problems.",
"well A: was historically the floppy disk drives, i remember A and B being 5.25 and 3.5\" floppy drives, then the hard drive was C and later cd drives were D: Of course A and B are gone now...",
"Historically the first two drives were designated A and B and were floppy disk drives. You might not even have a hard disk drive at all, just A for the disk with the program you wanted to run and B for a disk to store the output. As technology progressed the C drive being the first hard drive and the location of the operating system became the standard, and there was no reason to break with tradition."
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7e1c4f | Why do we wake up starving the morning after a night of binge eating? | Biology | explainlikeimfive | {
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"Insulins fucked it up. Your body needs glucose for energy. Everything you eat is broken down into glucose. 1. Foods like \"sugary\" foods, starch or very simple carbohydrates like rice, bread, pasta, etc, are digested very fast and thus, broken down and turned into glucose very fast. 2. Now, when you eat lots of those foods, lots of glucose goes into your blood very fast. And your pancrea produce little guys (hormones) called insulins who push that glucose into your cells. 3. When lots of glucose goes into your blood very fast, your organ pancrea freaks out and is like \"OMFG! Too much glucose in the blood. Too much glucose wandering around in the blood = poison!! Guys!!, Insulins!!, go go go!!! Go push them into the muscle cells and fat cells to properly store them.\" and then Pancrea produce lots of fucking insulins. May be even too much insulins. 4. Those lots of little fuckers called insulines push all the glucose from your blood into the cells. 5. Then, very low level of glucose in your blood. So, your body thinks \"Hey, my blood needs glucose. I need sugar(glucose). Feed me.\"",
"It depends on what you've eaten. When you eat a meal at bedtime, particularly one rich in sugars and other simple carbohydrates, you generate an insulin surge from your pancreas. Upon retiring, this insulin begins pushing glucose into your cells, a process that continues as you sleep. During the night, a continual drop in your blood glucose stimulates the release of counter-regulatory hormones, leading to stimulation of your appetite centers. Unless you get up in the middle of the night to satisfy your appetite, you will be hungry upon arising in the morning.",
"Probably too late to the answer party. But you're probably not actually hungry. The insulin answers are sort of right, but your body is very, very good at controlling glucose levels unless you're diabetic. It will have some fairly large swings after binge eating but by morning it should be mostly stabilized and your body has stored a lot of the calories (and used some of them). You're probably dehydrated. A lot of people can't differentiate properly between feelings of hunger and feelings of thirst (a lot of the time anyway). Combine not drinking for however many hours you were asleep, digestion itself requires energy and water. On top of that, glucose being forced into cells pulls water with them because now there's more stuff inside the cells and they want to keep the concentration of that stuff about the same as before. So try having a glass of water in the morning after binge eating, give it 30 minutes and you should feel mostly better. Edit: binge eating, not binge drinking. Though both apply sort of",
"What is happening blood sugar levels rebound from being way too high, temporarily putting you in a 'starving' state with regards to blood sugar. This is called [reactive hypoglycemia]( URL_0 ). Basically you are throwing your body's hormones way out of line. The large amount of insulin your body has to produce to deal with the amount of food you ate can lead to [type 2 diabetes]( URL_1 ), where your body becomes less responsive to insulin and you have to poke yourself with needles for pretty much the rest of your life.",
"Go check out the fasting and keto subs for a complete answer but essentially you are in a cycle of high glucose - insulin release - crash - hunger",
"We tend to think of hunger as an indicator that our stomach is empty but this is not how hunger works. Hunger is controlled by hormones and there is a psychological component. Whether you eat a lot or a little before bed, your body will have digested it all within 8 hours. The first hunger hormone is ghrelin which comes in waves. If you eat 3 meals a day every day, you will get 3 waves of ghrelin around those meal times. If you skip a meal you do not continue to get hungrier, but the hunger will go away (even though your stomach is still empty). If you fast for a few days, hunger can go away altogether. In your scenario, I think it is more about triggering a larger surge in ghrelin than it has to do with insulin. The body is good at regulating blood sugar and crashes are not as common as people make them out to be (this is a serious medical condition). Plus if you ate lots of carbs that means your glycogen stores are full and instead of blood sugar going low the body would just tap into these stores.",
"The question is why I'm not hungry in the morning, when the night before I was struggling falling asleep, because I was starving to death.",
"We usually get hungry every 4-5 hours during the day. We sleep usually 7-8 hours do it’s about that time to eat again. Your body has been digesting for a good amount of time",
"I think these answers are missing some subtle more nuanced points. Your body is always drawing energy from a blend of sources: simple sugars (sucrose, fructose), complex sugars (carbs), and fats (lipids). [Protein as well but we will leave that out for this discussion] Your body has evolved to VERY efficiently use everything you put into your mouth for energy so when you have a crazy night where you stuff yourself your body panics to make sure none of that valuable energy is wasted. If you have a normal diet (not over eating, low in added sugar, low in high glycemic starchy foods, and high in good fats and fibers) your body gets very comfortable flipping to using a higher percentage of fats (from foods and from cells). This is called ketogenic adaptation. Most modern adults have VERY poor ketogenic adaption. Basically we go all day with way too many calories in our diets. We spend all day with wild insulin rides because the body is constantly trying to shuttle all the excess food to muscles or fat. So most people with a modern diet wake up starving everyday because everyday is binge eating because they've lost all sense of what is 'normal' eating. When you binge eat you've just ratcheted an already lifelong problem to an even higher level. Binge eating also is normally partnered with lots of simple sugar consumption because sugar is everywhere in the american diet. It's even squirreled away in foods we don't think have sugar or don't taste sweet. And here's the last piece of the puzzle. People with normal diets get good at using fat and flipping to fat usage so at night as their bodies naturally slip into ketosis. They wake up with slight or zero hunger because they're using their own fat stores for energy upon waking. People that don't go into ketosis go to bed and their bodies are still very busy shuttling all the energy to fat but they never reverse the flow and start using fat. Insulin just keeps trying to drive glucose into the muscle and fat stores. In fact most people that undergo strict high fat low carb diet regimes become VERY ill for up to a week and feel like death because they are using metabolic pathways that their ancestors were using daily and they might not have used their entire lives. TL;DR most people on modern high fat, high starch, high sugar diets wake up hungry because of poor fat usage adaptation and binge eating just makes it worse.",
"This sucks worse when you eat a huge meal and go to take an hour nap, wake up and just immediate starving like you didn't eat anything.",
"Can I piggyback a question off this and ask if this is a similar reason for being hungry earlier if I eat breakfast, versus not being hungry until late afternoon if I skip breakfast?",
"On the evolutionary why (Why are we wired this way, instead of how the wiring works. There are already some very good answers on that): TL;DR: In a feast-and-famine environment, animals benefit from consuming as much as they can during the feast periods, and the most efficient way to do that is eat-sleep-eat. The same reason you can eat to your capacity even if you don't need that many calories is the reason you would come back for seconds. Long Version: Animals in general (including humans) are structured to accommodate a feast or famine environment. In an environment where food is scarce most of the time and plentiful for short periods, we eat as much as we can during the plentiful times in order to store energy for the leaner times. Even though overeating in an always plentiful environment is less healthy than moderate eating, not overeating in a feast-and-famine environment is often deadly. If you are a primitive human, who takes down a mammoth one night, you will have more food than you can eat. Because digestion systems take resources to maintain and you are not regularly confronted with more food than you can eat, it doesn't make sense to maintain the extra systems required for you to digest as much as you want quickly, so you fill up your systems when you eat. Once you are full, your body gets sleepy, that way you can devote as much energy to digesting as quick as possible as you can. After sleeping, your digestion system has mostly cleared (well, further down the pipeline), so you could consume more. Your dead mammoth is still there, and likely still edible. Thus your body gives you an incentive to keep consuming even more during this short period of abundance. Really, the need to survive through trying situations (like constant feast-or-famine) has royally screwed up our ability to maximize health in more stable situations.",
"Then why do I wake up starving af. Take 3 bites of food and feel sick? My body hates me..",
"When you eat so much before sleeping (probably lots of carbs/sugar) you wake up so hungry, because your body is now activated to burn all the food and while sleeping it will continue to do so. And after a long night rest of approx. 6h you wake up empty and hungry because your body has just been digesting and laying around."
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7e1coh | Why do non-clinical people (receptionists, etc.) in doctor’s offices wear scrubs? | Other | explainlikeimfive | {
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"People in reception, particularly in small offices, may wear a variety of hats during the day. Just because they are in reception at that moment doesn't mean they can't do other things where scrubs may be helpful. But primarily it becomes a uniform. Most of the other people working there wear scrubs so wearing them becomes a way to recognize an employee and show a uniformity of image.",
"Also an easy to choose outfit that is exposed to tons of germs that come off the moment you get home. Source: I’m a nurse",
"The posted answers are also correct, but the main reason is that there's a reason that scrubs exist. They're meant to be fluid resistant and easily removable in the case of biological contamination (spurting blood, oozing pus, etc.). There is a chance that even the receptionist in the course of her daily duties could be exposed to bodily fluids or chemicals, and so many offices ask/require that everyone wear scrubs or a lab coat just to be on the absolutely mostest safest side on the extremely off chance that someone comes in projectile vomiting or shitting all over their wheelchair. In some offices where they're absolutely positive the receptionist will never be exposed, they generally won't care what you wear."
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7e1f59 | What is Nitrous Oxide and how does is it make cars go faster? | Chemistry | explainlikeimfive | {
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"Nitrous oxide does a few things. It cools down the intake charge which makes it more dense. More density means more available oxygen. Then under heat and pressure it breaks down into oxygen and nitrogen which makes more oxygen available for combustion. More oxygen means you can burn more fuel, more fuel burned means more power. The breakdown of nitrous oxide is also exothermic, which further increases pressure on the combustion chamber, further increasing power.",
"Your engine produces power by combusting fuel. This combustion requires a specific ratio of fuel to oxygen. The ambient air going into your engine only has so much oxygen. If you provide too much fuel without increasing the oxygen level, you end up with incomplete combustion and less power is produced. This is called a rich mixture. To make more power, nitrous oxide is added to increase the amount of oxygen beyond what the ambient air contains. With all of this extra oxygen, you are able to add and combust more fuel per cycle. When more fuel is combusted completely, you make more power. TLDR: Nitrous oxide provides more oxygen. More oxygen means more fuel can be combusted. More fuel combusting means more power.",
"Who cares about making cars go fast... Have you ever breathed in the stuff. Pure mental magic. From its discovery by Sir Humphry Davy to inventors like Michael Faraday, and psychologists like William James... They all breathed in the sweet air, and went down the roller coaster of their own mind, and made the world a better place for it. Nitrous Oxide should never be wasted to make a combustion engine work harder, It should instead be inhaled to explore our selves deeper than previously possible.",
"Nitrous Oxide is really just not as good in cars as movies make it seem, but it's probably still the best power per dollar *while active*. A gasoline engine generates rotational energy through controlled combustion of air and fuel. If you *also* channel some compressed Nitrous Oxide into the air/fuel mixture, you can add more fuel and then make more power. Nitrous Oxide supplies more oxygen and cools the intake charge. We don't use pure oxygen because it would literally be too explosive. Nitrous Oxide is composed of one molecule oxygen and two molecules of nitrogen. The nitrogen helps to control the burn, so it happens during ignition rather than before. But this is a rather limited resource, so it's better suited to a drag strip than to a race track. Edit: hydrogen - > nitrogen, oops!"
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7e1fgj | Why do we struggle so much to learn how to ride a bike for the first time? Furthermore, why do we never forget how to ride a bike, regardless of how many years have passed? | Biology | explainlikeimfive | {
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"Your brain can very much unlearn how to ride a bike. What people mean when they say \"It's like riding a bicycle.\" is that once you learn it, it's very difficult to unlearn it. A lot of it has to do with unconscious muscle memory and learning. Watch [this video]( URL_0 ) to watch a guy unlearn his bike skills by learning to ride a *very* different bike. Edit: your",
"Our ability to learn something is based upon the similarity of that \"thing\" to other things we have interacted with. This is loosely defined as a \"poor training bias\", because we have no reference of training to make our learning easier. A strong training bias is when you have learned to do something, and your fine motor skills begin to take shape, like that video of people on bikes playing soccer. The bike-soccer is easier for them to learn, because they have a direct reference skill set their brain can draw upon. We don't forget how to ride a bike, because it takes major muscle groups and is fairly simple. It is a memory that has sunk into our brain due to repeated processes. However, if you ask good piano players to stop playing for several years, they will find they aren't able to produce music which is as sharply timed, and as elegant. The proficiency of their playing is based on muscle memory of fine-muscle groups, something which biking doesn't have. Biking is simple, compared to other things; once you have the general principal, its easy to remember. Ultimately it is based on our brains ability to recognize relevant patterns for muscle usage, and on the experience we have with those muscle usages. The simpler the task (relatively speaking), the easier it will be to remember."
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7e1hfm | Why do ads load first, rather than the content of the site itself? | Technology | explainlikeimfive | {
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"text": [
"Because the site gets paid for how many views on the ads they get. Therefore add content is more important than the actual content. Sites prioritize this to make sure they get paid essentially."
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5
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7e1iac | purchasing power parity (GDP)? | Economics | explainlikeimfive | {
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"text": [
"Say you live in the US. You make $100,000 a year. Now say you live in China, but you make $50,000 a year. You could say that the person living in the US is twice as rich as the Chinese person in absolute terms. But consider that lunch (a sandwich) costs $10 in the USA. It costs $1 in China. So an American can buy 10,000 lunches with their salary. The Chinese person can buy 50,000 lunches. That means the person in China is richer in terms of how much they can buy. Purchasing power parity is a way to weight the amount of money someone has by how much things cost to buy in their country. That's why global wealth inequality is so shocking. It's not just absolute wealth, it's based on PPP. Half the human population lives on less than $2.50 a day, after adjusting for PPP. A single mother in the US working 40 hours a week on minimum wage is significantly wealthier than 3 billion other humans. So basically, PPP is a way of weighting how much people make by the cost of living."
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7e1l76 | Why does someone with verbal Tourette’s often use swear/crude words? Society is the only thing that makes those words taboo, so why does it seem people with Tourette’s get stuck saying them? | Biology | explainlikeimfive | {
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"There is actually a specific part of the brain that is dedicated to housing these sorts of 'taboo' concepts. Anything that we're brought up to believe is taboo more or less gets stored here. The specific variety of Tourettes that causes the 'involuntary swearing' tick (there are many more cases of this disorder which do not exhibit that specific tick) apparently causes people to access these specific regions of the brain at random or under certain conditions. This is the least common variety of Tourettes, and it is much more common to see people with physical ticks (compulsions to move their hands, eyes, etc., In specific ways and so forth).",
"Have Tourette's with Corporalia AKA \"full blown Tourette's\". Also a science background/employment. Most people with Tourette's 'only' grunt or groan or have some minor physical tic like a fluttering eyelid. They often go undiagnosed because who cares if you grunt weirdly once in a while? Not worth the effort. People with the more severe version called Corporalia tend to hone in on specific words that *they* feel are taboo. This is often also what society thinks is taboo, because they were raised in that society and adopted it's moores. However this does not have to be the case - a person with no taboo against cursing won't curse, they'll make some other utterance that they think is taboo (such as a death threat or sexual come-on or talking about pedophilia). The biochemical basis is that your brain stores 'taboo' things in a certain brain region and people with Tourette's tend to activate that brain region randomly in association with speech. They are simply mis-wired. There's some Youtube videos from a guy with full Tourettes and he does not curse much - he yells about bombs. You can google them if you want to watch him go through an airport. In my case I genuinely don't view cussing as naughty - I cuss around little kids freely. I've never Tourette's a cussword (but it makes a handy excuse for my language!) - what I do Tourette yell is death threats and anti-authority slogans, stuff like \"Kill them all\" and \"I hate cops\" because that's what I consider taboo. Lately I've been throwing in the occasional \"I want a lover\" and \"I want to fuck her\" - I only now consider that taboo because I got married and we have a kid. Lucky for me I can control my Tourette's for moderate periods of time so I've never had any problems - I just suppress the urges. It's painful but it's better than paying lawyers fees to prove a mental issue in court to get the case dismissed (or a jumpy cop with a gun)."
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35,
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7e1v0b | Malleability vs. Ductility in metals | I understand the former deals with flattening, while the latter deals with stretching into a wire shape. But aren't these properties very similar? Where do these properties matter practically? | Physics | explainlikeimfive | {
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"Malleability refers to how much a material squishes out to the sides when you squeeze or hammer it. Ductility refers to how much a material can be stretched without breaking by pulling on it. They're both related to how easily particles (atoms, since we're only talking about metals) slide over each other, but the directions involved can be a deciding factor. Also, ductility is temperature dependent. At a certain low temperature depending on the metal (some metals actually become brittle at high temperature, but I don't know any examples, just that it's possible), it becomes easier to break the bonds between atoms instead of causing a deformation. This means the metal has become brittle and can no longer handle tensile force (stretching) When you bend an object. The part outside the bend gets stretched, and the part inside the bend gets squeezed. So temperature does affect bending as well. Really, any time any part of the metal gets stretched in any way, you look at its ductility. I want to say that any metal that is ductile must also be malleable, since stretching is a more concentrated force than squeezing, but I can't confirm that."
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7e1wqr | If I lift a pile of book and carry it towards another table, is work being done on the books? | Physics | explainlikeimfive | {
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"text": [
"Yes- not from any force in the vertical direction unless you move the pile upwards. The work done comes from the force x the direction of movement- meaning when you move the books horizontally work is done."
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4
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7e20n3 | Why do we suddenly have to pee in times of great stress? | Biology | explainlikeimfive | {
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"text": [
"You - stressed. Your brain - let the adrenal glands know we're stressed! And tell that fucker Cortisol to get back to his post! Adrenal glands - omg you Epinephrine little shits, why are you still here? they need you out there! Epinephrine little shits - fine! fine! But we wanna make a stop by the stomach, at some point. Gotta give this fucker his queasy feeling, ya know? Adrenal glands - just GO man. Report to the brain ASAP. Brain - why the fuck do you even show up here? Don't you know your job by now? Okay whatever, you guys, here, you guys, idk squeeze the blood vessels or some shit Blood vessels - AWWWWW YISS. Bladder - whoa where the fuck did all this water come from? Fuck man, get this shit outa here! Urinary tract - RGR THAT. DELIVERING PAYLOAD NOW. Edit - spelling",
"Our body tries to excrete so that we are lighter and more able to run away from predators. It's an instinctual response.",
"I don't know, but it must be similar to the reason why my dog has to pee the first time he sees me every day"
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7e27ky | How does "Whataboutism" differ from giving context to information? | Whataboutism is something I've heard and read a lot about in recent news, but I don't really 'get' it. How does giving additional information about similar situations somehow invalidate the point the person giving this information is trying to make? What are some examples of someone saying "That's whataboutism", but it actually isn't, what are examples of someone "just giving context", but it's actually whataboutism? Also, why did this term suddenly become a thing? | Other | explainlikeimfive | {
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"\"Whataboutism\" was a technique first used by the Soviet government and press in order to deflect criticism by America of the USSR's human rights record. Whenever an article appeared in an American newspaper of, for example, Stalin's purges, the Soviet press responded with a critique of racial segregation in the US. This happened so regularly, that it almost became a running gag that whatever America said, Russia replied: \"And you are lynching Negros.\" The point is that while it was certainly true that the US had serious problems with rampant institutionalised racism in some quarters, this had nothing to do with Stalin killing untold numbers of people who disagreed with him. As the old adage has it: \"Two wrongs don't make a right.\" \"Whataboutism\" is, at its core, an attempt to *change the subject*. Far from \"giving context\", it changes the subject to a different person (or country). There's no attempt to debunk the original criticism. For example, if Harry is accused of shoplifting, he can't defend himself by saying that Tom is a terrorist. Whether Tom is or isn't a terrorist is totally irrelevant to Harry's alleged shoplifting. But sometimes saying \"what about...?\" is legitimate. It's only legitimate if it *actually* addresses the topic at hand, for example: Mary: \"I heard the political party you support wants to ban sports. What's that all about?\" Helen: \"What about the party you support with its campaign to arm toddlers? Why aren't you talking about that?\" Here, Helen doesn't want to talk about the sports ban, so she tries to change the subject to guns for babies. Mary: \"I am a safe driver.\" Helen: \"What about all those tickets you got for speeding and DUI?\" Here, Helen is still talking about Mary's driving, but is simply calling into question her claim to be a safe driver by citing instances where she was caught driving dangerously.",
"Whataboutism is distraction. When you give context, it means you discuss what, say, Kevin Spacey did in light of other, similar incidents. Whataboutism is when you just make the conversation completely about Woodey Alan. And it didn't suddenly pop up, it was made to describe Soviet propaganda techniques, it just got poular suddenly. Why that is, I'd assume it's because of its mention in [Last Week Tonight's recent spot about Trump.]( URL_0 ) Edit: dulistraction - > distraction.",
"Whataboutism is a false equivalency used to suggest that the same or similar behavior on both sides is equivalent in scope, severity, effect, etc. Saudi Arabia oppresses women! They can't do x, y, z. Yeah, but what about America? This new piece of legislation is horribly oppressive. I've deliberately left out specific examples because I value the sanity of my inbox, but I don't think anyone would question that Saudi Arabia is a worse place to live for women. The two are NOT equivalent, and bringing up \"what about America?\" in this case is a whataboutism. Edit to answer your second question: whataboutism is the word because most of the offenders begin their sentences with \"what about ___\" which lends itself easily to new-word building. Whataboutism is in the *tu quoque* family of logical fallacies, which translates to \"you also.\" Being smart and using latin is kinda frowned upon in America, being seen as elitist or overly intellectual, so we made a new word both to avoid latin and to draw a distinction between \"you also\" and \" < Falsely Equivalent > also\"",
"It’s irrelevant distraction. Let’s say someone is talking about north korea’s human rights violations, then kim jong un says “well america also has human rights violations.” Whether or not other countries have human rights violations is irrelevant to issues in korea.",
"I would say whataboutism is a tactic that gives context to information, but with the intent to deflect consideration of that information.",
"Context is relevant to the discussion; whataboutism is a distraction from the actual topic at hand. Context: Seat belts save lives; there should be seat belts in school buses. Whataboutism: Seat belts may save lives, but there are none on motorcycles.",
"Whataboutism is usually used to deflect a specific wrongs by invoking the general wrongs of another group, creating a false equivalence. If you claim Roy Moore is unfit for office because of his sexual conduct, me responding by pointing out Bill Clinton's various scandals is whataboutism. Clinton behavior has nothing to do with Moore's fitness. However, if you made the general claim your should vote against the GOP for supporting Moore, then pointing to Clinton is fair game. > Also, why did this term suddenly become a thing? Whataboutism has a flip side, kind of like fake news. You can use it to point out irrelevant deflections, but you can also use it to mask your own hypocrisy when the equivalance is valid. Feel a little uncomfortable about your totally-not-racist singling out Islam as a danger? Just call anyone who points out the evils of other religions as a whataboutist and ignore everything else they have to say. It is slightly more effective than putting your fingers in your ears, and just as logically valid."
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7e2aak | Why isn't cancer contagious? | Biology | explainlikeimfive | {
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"text": [
"Cancer is essentially a mistake in the replication of DNA in your body (or some part of your body) that then keeps getting replicated. There's nothing that would be contagious (like a virus or flu). It's all just your DNA messing up."
],
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6
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7e2amt | How does it feel falling through a cloud while skydiving? Is it safe to perform such a feat? | Physics | explainlikeimfive | {
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"text": [
"As a pilot, I can advise that as a rule of thumb, clouds have turbulence. Not always bad turbulence, but I feel lik skydiving through them is asking. It some rough bumps. Just a WAG.",
"why wouldn't it be? clouds are made of microscopic bits of water. it'd be the same as sticking your head out of the car while passing thru fog (which is the same thing as cloud!)",
"It's a bit chilly and a bit damp, if they're white fluffy clouds. Falling through grey clouds is like being gently sandblasted, and while not dangerous is not exactly pleasant. The cloud itself won't hurt you, but it's not all that safe to fall through one. You can't see where you're going, you can't see what/who you might hit, and if you open your canopy in cloud you can become very disoriented and find yourself way off base when you finally come out the bottom of it."
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7e2bzi | Why do hot and steamy showers feel so comfortable but not hot weather? | Biology | explainlikeimfive | {
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"text": [
"Largely becasue you are naked and you can make it stop at any time. Hot showers are enjoyable not just for the heat, but for the physical sensation of water on your skin, and the combination of the hot from the water and the cool from evaporation. Also, if you do perspire, you don't notice with all the other water. Finally, you can also adjust them to exactly who hot you want, and turn it off when you have had enough. With hot weather, you get sweaty, your clothes absorb it and start to chafe, it gets in your eyes so you have to wipe your brow all the time, and it is just overall unpleasant.",
"Because hot weather lasts longer. I mean, a hot and steamy shower would probably start sucking after 2 hours..."
],
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19,
6
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|
7e2mgf | Why are most pencils painted yellow? Why not a different color? | Economics | explainlikeimfive | {
"a_id": [
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"text": [
"In the 1800s the best graphite came from China. In China the color yellow is associated with royalty and respect, so by painting the pencils yellow it conveyed that they came from China and had that esteemed nature. Of course a lot has changed since then but the norm of the yellow pencil remains."
],
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14
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|
7e2skn | Why do heat waves distort your vision? | Physics | explainlikeimfive | {
"a_id": [
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"text": [
"The air is physically at a different density and you are seeing the distortion of light as it moves through that region at a different angle and pace."
],
"score": [
4
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7e3ch6 | In the US, when a product is specified as freshly cooked or freshly baked, what does that mean and what is the lowest standard to classify as "fresh"? | Other | explainlikeimfive | {
"a_id": [
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"text": [
"In the case of juice in the US, for it to have the fresh label it cannot have been pasteurized per the FDA. So almost all juice you buy in the store is not fresh and seldom will you see it on the label. Regarding cooked foods I don't know if there is a legal requirement for that or not."
],
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6
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7e3j2x | How can the chlorine in tap water kill microorganisms, but not the cells in our bodies? | Biology | explainlikeimfive | {
"a_id": [
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"text": [
"It will kill cells in the body at high enough concentrations. Scientist and experts do their best to use as little as possible to get the job done and use \"just enough\" to get rid of the bacteria. Also, chlorine evaporates and degrades fairly quickly. So from the time the water is intitially treated to the time it eventually gets to your taps a lot of the chlorine is gone."
],
"score": [
8
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7e3pff | Do spiders ever forget where their webs are located? They leave but is it memory or something else they use to find their way back? | Biology | explainlikeimfive | {
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"text": [
"I once caught a, very distinct, spider and released it about 500 ft away from my home. What I didn't know, was that the spider had egg sacs hidden in her web under the baseboard heater. Well, she was back in her web about 2 days later! So, they definitely know where their webs are, and how to get back (within a reasonable distance).",
"Spiders are amazing animals...they have excellent eye sight and will remember where their webs are visually and by memory, to answer your question. If they find a spot in your home that they like, that is safe, provides food etc, they will keep coming back. If you destroy their webs they will build a new one, sometimes only inches away from the one you destroyed. They have two purposes..eat and reproduce. They eat other bugs, which is great, but not for most humans that hate them. A spider will repair a slightly broken web, and if a web seems weak over time, she will strengthen it with new silk, it's hard work. They will also extend their webs out further if needed. Spiders are not an indication of a dirty home, if you have a food source, they will eat. Getting rid of them depends on the type of spider. Pest control has many options including professional and do it yourself products...not recommended, the chemicals are dangerous and overdoing it makes it ineffective. Spiders, like many bugs, are killed in one of several ways...respiratory damage by inhalation or direct contact of a specific chemical is most effective (followed by sticky traps, literally squashing them, or direct spray). Bugs groom themselves, but a spiders feet are so tiny, it doesn't pick up enough chemical just walking over a spray you put around your house, to kill it. If you have dangerous spiders I would get a pro involved, if not, vacuum them, squash, sticky board, or direct spraying works. Some spiders are dangerous to animals and humans. They can be a help...they can be a hindrance, you may never get rid of every single one. Source: worked in pest control"
],
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7e3umf | How did Cinderella's shoe come off if it was the perfect fit? | Other | explainlikeimfive | {
"a_id": [
"dq2919p"
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"text": [
"A perfect fit doesn't mean it's impossible to remove. It just means that her foot isn't obviously too small or obviously too large for the shoe. Remember, it *is* a glass *slipper*, so it's intended to be slipped into and out of."
],
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3
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7e498c | How does an antihistamine work against an alergie? | Biology | explainlikeimfive | {
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"text": [
"Tldr; it inhibits the release of histamine from your MAST cells. So histamine release is good in localized areas. It causes 1Vasodilation (widening of blood vessels) to help bring more blood to the site 2 bronchospasm (constriction of the tubes in your lungs) which is good to prevent more of an inhaled allergen into your body 3 increases the permeability of the cells. Basically allowing stuff to flow more easily into and out of cells. All of this is great and is part of your body's immune system to help fight off allergy. The issue is when too much histamine is released. Then you can't profuse your body because your blood vessels are too dilated and you can't keep the blood pressure up. You can fully constrict your bronchioles, allowing less airflow into your lungs. You get pooling of fluids usually in the feet and lower to gravity parts of the body (dependent edema or pedal edema). So what's the solution? Epinephrine, more commonly known as adrenaline! Epi will activate your sympathetic nervous system, causing vasoconstriction, bronchodilation, and lowering the permeability of the cells. He'll fucking yes. But the issue is that epi occurs naturally in your body so you get it out of your system pretty efficiently (active times are roughly 5 minutes IV or the more common IM injection that lasts 20-30 minutes). So we give an antihistamine (benadryl) to stop histamine production. Wow it took a while to reach that answer",
"histamine- makes u itchy, body makes it when it detects an allergen antihistamine- makes that stop"
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7e49ht | What causes sleep paralysis?? | Biology | explainlikeimfive | {
"a_id": [
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"text": [
"Your brain releases lots of chemicals during sleep. One chemical paralyzes the body so you don't act out your dreams. Sometimes, the brain is able to \"wake up\" during this phase of sleep and become aware. However, there is a disconnect between this happening with the rest of your body, so it's still paralyzed even though you are partially aware. Interesting factoid about this is that even though you're aware, you're still fading in and out if REM sleep (the phase of sleep responsible for dreams). That said, many people report having extremely vivid hallucinations during this that appear absolutely real. Some say that this can be the cause of people reporting alien abductions or be in haunted by a ghost. The hallucinations are so vivid, they seem real, so people are usually convinced that what they experienced was reality when it was simply just a dream."
],
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3
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7e4h6f | Why is water 'harder than concrete' if you fall into it from a great height? | Physics | explainlikeimfive | {
"a_id": [
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"text": [
"It is not harder, but at high enought speed the effect is the same. You die. Imagine for example what happens when you slowly soak your hand in water, there is no resistance. Slap the water and you will feel the impact. Slap it hard enought and you will feel pain. This happens because when you go slow the water mollecules have enought time to get out of your way. The faster you go the harder you will have to push to make them move faster. Go fast enought and they will really resist it so hard they will feel like a solid to you. Consider that what kills you is not the fall but the sudden stop at the end. Ig you go slow the water will resist you enought to gently stop you but if you go fast enought it will stop you suddently."
],
"score": [
15
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|
7e4jxu | Would tattoos on someone with a weak immune system fade slower than on someone with a excellent immune system? | Biology | explainlikeimfive | {
"a_id": [
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"text": [
"A few weeks after you get the tattoo the pigments that remain have been eaten by immune cells which get stuck and stay in a layer of your skin. So the 'immune process' is over and done with in all individuals long before the tattoo degrades. The fading is (afaik) mostly due to unrelated breakdown of the pigments (sunlight being the biggest factor) and is not due to the immune system."
],
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4
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|
7e4op2 | Being in shock/adrenaline | Anytime I hear stories about a person getting into an accident, sometimes where limbs come off, and they act normal, like they will walk towards their car, sit down and chill, or call ambulance, or whatever. Someone in the comments will always ask why, and someone will reply saying because they are in shock. What is shock really? I feel like if my arm just came off, there's nothing I can do about other than chill out and call emergency, would this be considered "shock." Obviously, the adrenaline would mask most of the pain but screaming in agony or just looking at the wound won't help so whenever I see a person in "shock" I don't really think they are out of it, I think they are composed and accepted what just happened. | Biology | explainlikeimfive | {
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],
"text": [
"Shock is when your blood pressure is substantially lowered caused by (mainly) physical trauma. Poor blood pressure = cell damage, disoriented, confused. altered consciousness basically a lot of stuff happens to our brain when our blood pressure is lowered drastically. In instances where people are in an accident and have undergone an injury to which an unaffected person at the time would be freaking out about if observed, but the affected person remains calm but sort of \"out of it\" - this would be adrenaline. Adrenaline would kick in before shock because its our defense mechanism known as fight or flight. Your brain basically directs all its attention to keeping your body alive. Therefor there is basically no concentration being used towards pain or shocking visuals - just solely on figuring out what you need to do to get out of the situation. Adrenaline is something that we can't physically control like holding our breath, it happens regardless. So people with a limb missing from an accident are having a huge adrenaline surge and remain calm because the part of the brain that is response for pain shuts down to keep the person concentrated and alert for danger. This is why when people that do excessive amounts of amphetamines feel almost no pain or at least don't react to it. This is because amphetamines are a stimulant that release a crap load of mainly dopamine but also Adrenaline. Basically you're putting your body into fight or flight for no reason. Hope this helps."
],
"score": [
5
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
7e4xy8 | Why do some people not care about the activity and just enjoy the companionship? | Is there a name for this trait? | Other | explainlikeimfive | {
"a_id": [
"dq2uvac"
],
"text": [
"They're probably introverts.Socializing can be tiring for them but they still enjoy having a friend around."
],
"score": [
3
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
7e4y80 | How come I'm no longer hungry after cooking? | Whenever I start cooking I'm starving, but by the time I finish I'm not hungry anymore. Why? | Biology | explainlikeimfive | {
"a_id": [
"dq2i7kc"
],
"text": [
"Because you're snacking while preping? And your blood sugar levels go up."
],
"score": [
3
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
7e51cm | Short selling. How can you make money betting against a stock? | Economics | explainlikeimfive | {
"a_id": [
"dq2iezz"
],
"text": [
"If I told you I was going out of town and could pick up something you wanted, I could ask for the money up front. We both know what it's worth now. However, when I actually get there, the price has dropped, and I just pocket the difference."
],
"score": [
3
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
7e5637 | When doing the same amount of physical labor, why do some people sweat a lot while others don't? | Biology | explainlikeimfive | {
"a_id": [
"dq2ouj7"
],
"text": [
"Differing homeostasis methods that only work right under some circumstances. People genetically adapted to high heat with lots of environmental water will sweat a lot, and quickly, when under stress, because that's the optimal outcome. People descended from wetter climes will sweat less but maybe reduce their metabolism to reduce heat generation. It's also a matter of fitness, people who are fit will tend to sweat 'sooner' than people who are unfit - their bodies know that they need to cool off fast before the workout starts. Some rare people have disorders - they sweat constantly or at the slightest provocation, or they don't sweat at all."
],
"score": [
37
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
7e5hwk | Why is it so difficult to color match paint? | Several times I have tried to color match paint and it never works. In some cases it isn't even close. Even if I know the name of the color I used, a new can still doesn't match. It seems like it shouldn't be this difficult to make the same color twice. | Other | explainlikeimfive | {
"a_id": [
"dq2p3hx"
],
"text": [
"Let me start by saying I match colors for a living for a paint company. So there are a lot of reasons it's difficult to color match paint especially if you are not using a paint machine. First reason everyone sees colors slightly different. When me and my coworkers are working on matching colors a lot of the time we will all see it differently. Another reason could be that if you are trying to match a color from another company they may use different pigment which could have different chemistry causing a slight difference. Another huge issue is lighting. Colors will look different in different light sources, this is called metamerism. If you are asking why the paint machines have issues with colors being the same they have their own set of problems. They have preloaded formulas which are then pumped out and measured by volume. Now when we do matches we measure pigments by mass. The conversion from mass to volume will cause slight variations. Also the pumping mechanisms aren't perfect. Another problem with these machines is if the pigments are agitated enough it could cause the concentration to be wrong thus raising or lowering the tint strength of the pigment."
],
"score": [
3
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
7e5k23 | Why do mood swings occur? | Biology | explainlikeimfive | {
"a_id": [
"dq2mzzc"
],
"text": [
"Mood swings refer to a rapid change in mood. They can occur in women who suffer from PMS or people who suffer from more serious disorders such an major depression, bipolar disorder, ADHD, schizophrenia, or other mood disorders. They can also be caused by thyroid disorders. From my limited understanding on mood swings (I'm bipolar and have ADHD) there are neurotransmitters at play, one of them being serotonin. If a person has an abnormal amount of a neurotransmitter, this may result in a mood swing disorder (such as bipolar or ADHD). Serotonin is one such neurotransmitter which is involved in regulating our mood, sleep, and overall emotional state. Not eating or changes in your sleep patterns might alter your mood and therefore cause a swing as it would alter your serotonin levels and blood sugar. Someone more well-versed will likely come along."
],
"score": [
4
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
7e5kk3 | What is protein folding and why does running simulations of it take so much compute power? | Biology | explainlikeimfive | {
"a_id": [
"dq2o4v4",
"dq2oexu"
],
"text": [
"Protein folding is essentially figuring out what the shape of a certain protein will be if it was made. You input its chemical structure and the program has to figure out how each part interacts with every other part. This takes a lot of processing power because the number of interactions grows very fast. A protein with 5 parts has 120 different groups of interactions to take into account, a protein with 6 has 720, 7 has 5040 and so on. because this number rises very quickly and since most proteins have tens of parts, it takes a lot of processing power to simulate protein folding.",
"Proteins have various structural layers. * Primary structure is the sequence of amino acids that make up the protein * Secondary structure consists of so-called 'motifs' like alpha helices, beta pleated sheets etc, which are how local regions of the protein fold together * Tertiary structure is the overall 3-dimensional shape of the protein * Quaternary structure is used when proteins have sub-units and refers to how they fit together There are lots of different types of proteins but I'm going to use enzymes to start off with. Enzymes are proteins that cause another chemical reaction to happen or to happen faster. They mostly have a part of themselves called the \"active site\" which is where the interesting chemistry happens. The Holy Grail of protein chemistry is being able to predict the tertiary structure of a protein from just the primary structure ie. given the sequence of amino acids, what does the final protein look like. If we could do this, it would have huge implications for drug design and treatment of some diseases. The problem is that there are lots of different ways that proteins can fold because the amino acids themselves like to interact. One of the simplest is the formation of disulfide bridges between cysteines in the protein chain. The primary structure might contain many cysteines but only a few of them actually link up and the cysteines that link up might not actually be close to each other. So the more cysteines you have, the harder it is to predict the final structure. But that's not all. There are many, many other ways that proteins can fold. They can form hydrogen bonds between amino acids, the secondary structure can constrain folding or there can be subtle Van der Waal's bonds between portions of the chain. What this all means is that the folding of proteins is an incredibly complex process that is not easily predicted at all and becomes virtually impossible once you get to a protein of any significant size. On top of this, some proteins actually have multiple stable folding states. Often these proteins can change their tertiary structure based on some internal chemistry eg. an enzyme can change its structure at low pH to expose the active site while at higher pH the active site is closed off. So even if you can predict the tertiary structure, it's hard to know if you've predicted it correctly."
],
"score": [
7,
6
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
7e5m0p | How did the Game Genie from Galoob work as a cheat device? | Technology | explainlikeimfive | {
"a_id": [
"dq2nj9t"
],
"text": [
"Well information about how the game operates is stored in registers. So your lives is stored in a register with a set number say 5. Should your character in the game dies the game is programmed to take the register for lives and subtract one. When the number is zero, it access the game over mode. The Game Genie intercepted this data and the codes would modify the programming so that it would ignore the lives -1 command that the game would send out or it could modify the state beyond what was hard coded in. It could also modify other values like say, what your jump height would be or your speed of movement."
],
"score": [
4
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
7e5x4z | What’s a manifold? | Mathematics | explainlikeimfive | {
"a_id": [
"dq2ry51"
],
"text": [
"It's an object like, say, a klein bottle, which has the property: for any point on the object, you can examine the area around that point, and that area will have the same basic topology as **R**^n . For a Klein bottle- even though the bottle itself has weird stuff going on- little pieces of it are basically just ordinary two-dimensional chips."
],
"score": [
4
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
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