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n7b2yt | What is the biological significance of monogamy in humans? | Biology | explainlikeimfive | {
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"Humans are fairly unique in monogomy. The evolutionary advantage of it was women would have one child at a time and both parents would be able to raise the child. This allows the child to develop better social interactions and learn lessons from tow adults as opposed to one. Almost every successful culture developed with these base family units in monogomy relationships. Cultures that didn't have this two parent model struggled in other ways.",
"Humans are different than alot of other animals in that we are not born being able to care for ourselves (prioritization of big heads and brains and all that). Having tight bonds with the offspring's parent meant that food was brought to the mother and baby who would have been quite vulnerable in the wild and more likely to protect them (same reasons why babies generally look like more their fathers for several months). Today, well, anyone can make whatever decisions they want because it's less survival and more social connection."
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n7b7oq | Why is bread considered safe to store at room temperature even though it's high in moisture and contains ingredients that can otherwise spoil? | Chemistry | explainlikeimfive | {
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"The real answer is: preservatives Source: I make homemade bread a lot. Two or three days on the counter and it's moldy. It's usually not an issue, though, as it's usually eaten within a day. Edit: sealed, on the counter, for clarification.",
"Bread does commonly spoil - it's called mold. The thing about mold is that it's easily detected (it's green or white), it grows on the surface, and it tastes foul. So you're not really likely to poison yourself on spoiled bread. If contained properly (ie, in a bag) bread usually goes stale before it grows mold anyway. edit: I will add that many commercial / mass market bread brands additionally add preservatives (like sugar)",
"Bread is only safe to store that way because it is sold in small quantities and people use it frequently, so it is usually consumed before it has a chance to go bad. I only eat bread once a month or so, so I have to keep mine in the freezer.",
"Because when it is cooked properly, everything INSIDE should die. Thus to spoil a freshly cooked bread, it has to work from outside to inside the bread. which is why when you have mold on your bread, you can just remove the outside and still eat it (not recommended) Another thing is \"its safe to store\" for a usually less than a week, try 2 week bread and you will find mold inevitably. A lot of food is safe to store for the same amount of time. But a lot of food don't see nearly as much consumption as bread. Thus bread is one of the few food guarantied to be eaten before it spoils.",
"There is a difference between pathogens on the outside of something, and pathogens on the inside of something. Whether it's bread, or tomatoes, or a wheel of cheese, the more you expose it's insides, the faster it will rot. Unsliced bread can keep quite a while because any yeast or bacteria inside of it were autoclaved by the baking process and are dead. The outside surface is exposed, but believe it or not, it's difficult to start a colony like that without literally digging in for protection. This is also why you can have fungus and bacterial colonies on your skin, and yet not get sick. But when you slice bread, or break it up, or expose more surface area, it will spoil faster, usually from fungal spores. This is also why whole fruit is counter top safe, but when you start slicing it, it can go moldy in days. This is also why dry aging meat doesn't make people sick. The inside part of the meat is not exposed and so doesn't rot, and the part that does rot is cut away from the outside in. This is also why an entire wheel of cheese might sit for years in a well controlled environment without rotting, but sliced cheese turns moldy in a few days on the table, or weeks in the fridge."
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n7b93c | How does dehydration for several days give you more defined muscles? | Biology | explainlikeimfive | {
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"If you had a bag full of water and you put your hand under it and lifted up a bit the upper surface of the bag would probably not change shape much. If you then let all the water out you'd be able to see the shape of your hand much more clearly"
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n7biwo | Why humans grow toenails | Physics | explainlikeimfive | {
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"Before humans were humans they were claws. Now they make a human toes that are squishy a little less squishy. Instead of being used for traction like a regular claw would, they instead are used to provide a firm backing for the toe.",
"Our tree-dwelling ancestors had feet similar to hands for climbing. Like with our hands today, the toenails protected the distal phalanges and let the toes scrape/scratch/pick up small things. When we started spending most of our time on land, our feet became more “foot shaped” and our toes got smaller. But there hasn’t been enough selective pressure to completely remove the toenail."
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n7bjnh | Back in the late 90s and early 2000s laser pointers were very popular and you could put different tips in them to get different designs, how did those tips work? | Technology | explainlikeimfive | {
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"The lens have a structure called \"diffraction grating\". If you watch ocean waves passing around a series of rocks, you'll notice that part of the wave is reflected and overlaps with the original wave, making a complex pattern. That pattern depends on how the rocks are arranged. Since the laser light behaves like a wave, the same strategy can be used to make the wanted pattern. The lens have a series of cuts that behave like the rocks in the example and are arranged in a way that creates the desired image."
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n7bsiy | How does immigration benefit the economy and businnesses? | Economics | explainlikeimfive | {
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"Idk where you’re getting the idea that Japan’s economy is “strong”. Their bubble burst in the late 90’s and they’ve just muddled along ever since. And to answer your question, it’s because immigrants arrive in your country and start doing productive things. They increase demand for current business and even start a few of their own. And highly-skilled immigrants are the real prize: some other country shoulders the burden of educating them and you get to reap the benefits!"
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n7bssb | why do most electronics, like controllers and remotes, need two batteries instead of one? | Technology | explainlikeimfive | {
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"Modern electronics operate off of semiconductors. Diodes and transistors. This includes LED's. These are electronic devices which do almost nothing below a set voltage. Only above this voltage do they become active. While the exact voltage can vary, this would usually be near or above the voltage of one battery (1.5 v). So, to get some function out of them, the voltage must be raised a bit. The easiest way to do this is to add a second battery.",
"They do not need two batteries you could make a remote that only use one battery. The problem is that the voltage that you need of a typical IR LED is 1.4 -1.6 V. There will be some voltage drop over the transistors you use to control it. The other chips will also have a min operational voltage. A new AA and AAA battery is at 1.5 but drops quickly when you use it. The voltage when almost empty is a bit over 1V. A rechargeable AA battery is at only 1.2V With 1 battery the device needs to operate at 1.5V and need to go down to 1.0V to use most of the battery but with 2 batteries you are at 3V to 2V The voltage range for a single battery will be too low to operate an IR LED quite quickly so you need to add a DC-DC boos circuit. The problem is that the will reduce efficiency because voltage conversion is not 100% efficient. So one battery will last less the half of two. The extra circuits also some money. Not a lot but the cost is higher than including an extra battery with the remote. There are 3V button cell batteries that are smaller and when you find them in remotes they tend to use only one. For consumers the 3V battery has some problem, there is a lot of sizes so to have extra at home require lot of batteries. They are often very expensive in stores to compare to AA and AAA batteries. So for a device that fits a AA or AAA they are a cheaper and more practical option for the consumer. The result is for remotes where you do not need minimal size the best option for the manufacturer is to use 2 batteries. for minimal size, a 3V button cell is used."
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n7cwxo | If you have bad eyesight, why are far objects in mirrors still blurry despite the mirror being close? | Physics | explainlikeimfive | {
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"The 'optical distance' has not changed. The blurriness, to ELI5, is based on how much the light has spread out since it started. The farther it travels, the more it spreads out. The mirror does not cause it to scatter anew - if it did it would appear white instead of reflective. It retains the original amount of spreading out, and so the light has effectively just continued to travel.",
"The distance that light travels is still the same - long. If you're 1m away from the mirror and the mirror is 9m away from what you're looking at, you're effectively looking at something 10m away because light needs to travel 10m to reach your eyes",
"Because you're not focusing on the mirror, but on the objects that appear 'behind' it. It's the same as how looking at something through a window doesn't change the amount you need to focus. When you look at something, rays of light travel to the top and the bottom of your eye. (Also all over, but let's focus on top and bottom.) They arrive at a certain angle. Your eye has to change that angle using a lens so they hit the same point on the back of your eye. The thing that matters here is the angle between them. When you look at something either in a mirror or through a window, the rays that hit the top and bottom of your eye hit different bits of the glass. They reflect or go through different parts and arrive at your eye with the same angle. It's like the mirror or glass wasn't actually there. So, your eye still has to do the same job to focus them."
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n7d8pt | How does a computer keep track of time when turned off? | Technology | explainlikeimfive | {
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"Some components of the computer do not turn off, and are sustained by an internal battery. This includes the clock.",
"They have a small button-cell battery. If you have an old computer that loses track of the time when it gets turned off, you just need to change that to fix it.",
"Inside your computer is a motherboard and the thing that controls it is called the BIOS (basic input output system). On the motherboard there's a chip for the clock and that chip is powered, as others have said, by a cr32 battery so it's never powered down. That's how your computer knows what time it is.",
"Some computers make a call out to an atomic clock over the internet to get the most up to date time"
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n7dqon | how does allergy immunotherapy work? | Biology | explainlikeimfive | {
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"Imagine trying to take a cold shower. If you don't normally do those, it would be hard, right? You might **react** by jumping out of the way, looking for a towel, and turning the water off. But what if you started on warm, then kept turning the temperature down by a little bit? The change in temperature wouldn't be so shocking anymore, as long as you gave yourself plenty of time to get used to each temperature. Eventually, you would be standing under cold water and not react to it. Same with immunotherapy, you give the person a tiiiny does of the allergen increasing over time to get their body to stop reacting so violently. The reason you don't get used to the allergen in regular life is because the dose is too big, so you get a reaction instead of getting used to it. In the lab setting, they're able to get allergens to be small enough not to cause a reaction. Although it definitely happenes sometimes, which is why you gotta wait 20 minutes after the shot before you can leave. If they give you too much and you have a reaction, next time they'd start from a really tiny dose again and keep increasing it over time."
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n7e1dw | What is the difference between Yuan, Renminbi, CNY and CNH? | Economics | explainlikeimfive | {
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"The name of the Chinese currency is the **renminbi**, typically written as **RMB**. Each unit is called a **yuan** (¥). In the “physical” world you withdraw RMB. For example, when you withdraw Chinese currency at an ATM in Mainland China you get RMB **CNY** and **CNH** are both *types* of RMB (1 CNY = 1 RMB = 1 yuan and 1 CNH = 1 RMB = 1 yuan). They however don’t necessarily trade at the same price against foreign currencies. In the foreign exchange market, there is a difference between whether it is onshore or offshore: 1. CNY (onshore – RMB traded within Mainland China) 2. CNH (offshore – RMB traded outside of Mainland China) The value of CNY is controlled by the Chinese government. The People’s Bank of China publishes a reference rate for the currency each day. CNH, however, is traded freely in global markets, its value changes based on the market and it is not controlled by the government."
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n7enno | why do we blink at a big noise, like hammering? | Biology | explainlikeimfive | {
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"Best evolutionary response to any sudden stimulus was to also close the eyelids. Less blind, more babies.",
"When something bad happens really suddenly, we don’t have time to process it with our brain before we face some negative consequences. Like when you touch a hot pan, the signal to pull away your arm actually comes from the spinal cord. You might actually even feel as if you didn’t notice it was hot until after you pulled away. So when a loud noise happens, our bodies completely unconsciously have to make something happen in case it was dangerous. There’s no time to process what the danger was because, if we do, we might go blind. Thus, blink your eyes and recoil away a little bit to try and dodge the bad thing just in case before knowing if it’s actually bad. Better safe than sorry, says the spinal cord.",
"It's more of a flinch. I'm sure there is a professional that can answer better. But it must be part of the fight or flight in our brain. Loud noises are 'scary'.",
"This was an incredibly hard reaction to overcome in orchestra during the holiday season. The horseshoe whip was just two wooden planks with handles to smack together . We had a day where we just played a single long note eyes closed while the player walked around “cracking it.” Now I am evolutionarily inferior because I just keep my eyes wide open hahah"
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n7ffve | If heat is particles moving fast and cold is particles moving slow, why does wind cool you down even though its moving fast? | Physics | explainlikeimfive | {
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"It's not them 'moving its them 'vibrating. Think about a red hot block of steel that's not moving. It's hot because energy has been added to it which causes the steel molecules to vibrate faster than they would at room temperature. They'll slow down their vibrations as the heat gets transferred into the ambient air. Tldr, energy causes molecules to vibrate, which eventually release the energy as heat"
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n7g279 | Why do job listings rarely list the wage Lets not pretend there is another reason for wanting a job? | Other | explainlikeimfive | {
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"Because they don't want to give you any more information. They want the best candidates at the lowest price. They'll go as low as they can, to reasonably get you. If that's minimum wage, then so be it. It gets them the broadest group of applicants that way."
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n7g2z9 | - How does a Boomerang work? | I genuinely don’t understand, please explain | Physics | explainlikeimfive | {
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"URL_0 I’m going to try my best to interpret here: basically a boomerang is built to have an aerofoil (wing) always at the top edge of the object. An aerofoil causes air to move faster around it, which creates lift. What this accomplishes is that the boomerang is pushed to the left (most boomerangs I’ve seen are left-rotating) from whatever direction it is parallel to. If you get enough spin that that aerofoil turns through enough air to push it just at the right rate and right amount, you can get it to come right back to you. Otherwise it whizzes past you and you duck anyways. This is my basic understanding. I may be wrong, at parts, but I know for a fact that the boomerang is shaped like a plane’s wing, and instead of getting lift upwards it gets most of the lift normal to the boomerang as torque."
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n7ga3m | Why are protons specifically positively charged while electrons are specifically negatively charged, and not the other way around? | Chemistry | explainlikeimfive | {
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"Because we had to pick one to be negative and one to be positive. They could have called them black and white charges (although, as of right now, colors have already been claimed by another force), or day and night charges. It's just a convenience, so we know they are opposite charges.",
"Technically speaking, charge is an fundamental property of matter. For electrons, their -1 charge is an inherent characteristic. Nothing causes it. That’s just how they are. Protons and neutrons are a little different. Their charge is caused by quarks. Quarks have a charge of either -1/3 or +2/3. Two Up Quarks (2/3 + 2/3) and one Down Quark (-1/3) makes a Proton (+1). Two Down Quarks (-1/3 + -1/3) and one Up Quark (2/3) makes a Neutron (0). This is just human math to help us understand their physical properties."
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n7gmrx | How do people die from cancer? | Biology | explainlikeimfive | {
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"Cancer, by physically replacing, destroying, starving healthy tissue means that that tissue can no longer support your life. Eventually your body loses so much of that function that it dies, whether it's because your kidneys gave out, your lungs stopped exchanging gas, or an infection takes over because your immune system is gone. The destruction of certain tissues is also an issue when that tissue is something like bone, which when eaten away, releases calcium into the blood and if that goes too high too quickly is dangerous. The second is that cancer is much more metabolically active than regular tissue and grows to abnormal sizes. This means that there are occasionally die-offs of parts of the tumour, releasing things like potassium, calcium, other chemicals into your blood at levels much higher than is compatible with life and the body can correct in the available time. This is called tumour lysis syndrome, and can sometimes happen with chemotherapy as well.",
"You *can* cut out tumors, sometimes. But the procedure can be extremely dangerous depending on where the tumor is, if it’s even accessible. You can’t cut away part of a lung, or a stomach. Breast? Skin? In early stages, that can be much more treatable. The problem comes in that it’s really damn hard to make sure you get every single cancerous cell without hurting too many healthy ones, because if you don’t the tumor regrows. And those tumors can kill you by disrupting vital organs or weakening your body for infections. Tumors can starve healthy cells out of oxygen, energy, and nutrients, which is obviously no bueno. Brain tumors are exceedingly dangerous, Bc the wrong neurons go and you’re suddenly a vegetable- if you’re lucky. In the case of cancer in the leg or arm, doctors could definitely cut out or kill the tumor without needing to worry about damaging vital organs. In the worst case, you could just cut off the limb at an appropriate joint. I’ve never heard of leg or arm cancer though.",
"There are many many many different cancers, and many many many ways they kill you. Here are some examples from my own life: \\- My mother's father died from colon cancer. Eventually the tumor grew so big that he could no longer pass food and waste through his digestive tract. So he died. \\- My father's father died from lung cancer. He eventually couldn't get enough oxygen into his blood so he died. \\- My father died of Multiple Myeloma. That cancer attacks many things in your body, but really goes after your bones. The bones release calcium into the blood stream when attacked, which killed his kidneys. He wasn't a candidate for a kidney transplant so the continuous dialysis just weakened his body. He was also always going into congestive heart failure. Eventually he had a massive heart attack and died. \\- My mother died of anaplastic thyroid cancer. It is a very aggressive form of cancer, and it spread and created tumors in her lungs. After just a few months she could no longer breathe and she died. \\- My uncle died of brain cancer. The tumor kept growing and growing and taking over his brain to the point where he eventually just died as there wasn't enough functioning brain left to keep his body alive. There are also cancers that attack blood production, white cell production, liver, pancreas (like Steve Jobs), etc, etc, etc. Cancer can be everywhere. It eventually kills you by destroying vital parts of your body that you can't live without.",
"The problem is that cancerous cells replace/overwhelm non-cancerous cells. It sounds like you're picturing tumors as random lump that grows somewhere. While tumors are lumpy, cancer is much more complicated than that Cancerous cells are mutations from normal cells and do things like: * Divide too often, leading to many more cell than necessary * Don't die off naturally at the correct time. All cells in the body eventually die to be replaced, but cancerous cells suppress this for as long as possible * The ability to integrate with blood vessels and develop their own blood vessel system, like an organ of the body does except it's sustaining this tumor that doesn't contribute * Move to other parts of the body where they don't belong and start replicating there, too (metastasis, as in \"the cancer has metastasized\") Cancer cells are badly formed and can no longer fulfill their original function, but they are reproducing way more quickly than healthy cells, *and* aren't dying. Essentially, they overwhelm the other cells, taking up space and resources (like growing blood vessels within a tumor) so that the original cells cannot due what they're supposed to do. The specific cause of death varies depending on the type of cancer and where it's metastasized to. Skin cancer is usually the easiest to stop because, as you noted, you can cut it out fully and there's less of a chance that the damage done cutting it out is life-threatening. In the case of lung cancer, you may be unable to absorb the oxygen you need. For bone cancer, your bone marrow stops being able to produce enough blood cells (red blood cells to carry oxygen, white blood cells to fight infection, platelets to stop bleeding), so either it can be an unrelated disease you are unable to fight off, or organ failure because one of your organs does not get enough oxygen. Cancer that starts in non-essential organs usually causes death if it's manage to metastasized somewhere else. Another cause of death is from damage to blood vessels from the tumor (eg., a stroke or other reason an area of the body doesn't get the blood it needs)."
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n7hec7 | Why do Oreo crumbs form a star-like shape after dipped in milk? | After I dunk a bunch of Oreos in a small bowl of milk, the crumbs make this shape after about 20 minutes. It gets progressively more clustered in the middle as time goes on. | Other | explainlikeimfive | {
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"I don't know, but who dips cookies in a bowl?! Madmen.",
"ELI5: Why don't you eat your goddamn Oreos?",
"It's how small particles react to the surface tension of a liquid. They just kinda poof out. See other responses for more scientific answers",
"I don’t think anyone is going to be able to answer your question OP, because what kind of sociopath dips Oreos in a bowl of milk and lets it sit there for 20 minutes. (It’s probably the Cheerios Effect)"
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n7hsfg | Why are some magazines for weapons curved, and others straight? | An example of this is 7.62x51 NATO, typically in 20-round magazines, but there are also some 7.62 magazines that are curved and not straight. Magazines for 7.62x39mm also have a distinctive curve, which is more extreme compared to other magazines of other calibers. Why is this the case? | Technology | explainlikeimfive | {
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"> 7.62x51 NATO This cartridge has a casing body with [sides which are parallel]( URL_0 ). Stack them on top of each other and you get a straight stack. > 7.62x39mm This cartridge has a casing body with [sides that are angled toward the tip]( URL_1 ). If you stack them on top of each other you get a curve. Curving a magazine can provide more space for ammunition without excessively expanding the space requirements of the weapon, but the shape of the cartridge itself shouldn't be ignored.",
"2 reasons: The first is that many carbine and rifle cartridges have tapered cases, meaning that when they nest together, t[hey naturally form a curve]( URL_0 ). Magazines meant to hold a specific cartridge tend to follow this curve, which makes feeding cartridges into the gun more reliable. The second is that beyond more than 20 rounds, for an intermediate or full power cartridge, the magazine just sticks out too far. Curving it allows the cartridges to hold 30 rounds without sticking too far below the gun which would make it difficult to fire in a prone position."
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n7jxh1 | What biological advantage is there for the viral pathogen if its host dies? | Biology | explainlikeimfive | {
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"Natural selection only cares if the genetic information is passed on, so the virus will continue to evolve if it can spread before that happens.",
"None. Pathogens don’t think. They don’t try to do more or less harm or have any tactics whatsoever. They infect, mutate and the mutations which are contagious and don’t kill their host too quickly continue to reproduce. Those that kill the host quickly or are not contagious die",
"Aggressive pathogens will replicate themselves much faster increasing the chance of infecting other hosts a lot. The disadvantage to this is that the host will become ill quicker causing them to isolate themselves reducing the chance of infecting others. So there are a lot of things determining which strategy is best. However evolution rarely produce the best results, only good enough. Especially with things like pathogens which often evolve quickly and infects different types of hosts which also changes fast. So the same pathogen that is very stealthy in some hosts and is able to infect lots of others before the immune system gets to react to their presence may be too aggressive in other hosts."
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n7k4d2 | How do we experience Temperature? | Physics | explainlikeimfive | {
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"For the most part, you don't really feel temperature, your senses feel the flow of heat. If you touch something cold, you feel the heat leaving your hands, if you touch something hot you feel the heat enter your hands This sounds similar, but explains some of the quirks and flaws in the way we experience temperature. Metals feel colder and warmer than ceramics at similar temperatures cause they are are thermally conductive. Also, if you cool your hands with ice water, then pick up something cold, it will feel warmer than it should be, because the temperature of your hands means less heat can leave your hands.",
"If you mean biomechanically, then we have two types of receptive cells, for cold and heat. And in each type of cells there's a bunch of proteins that change their shape at different temperatures and that activates nerve signal transmission into the brain, which perceived as a cold, warmth or burning hot (above \\~45C)."
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n7kqzu | Why can't we replace plastic bottles with carton boxes (like the ones used for juice boxes) when packaging products like shampoo? | Since they are used to package juice they are clearly waterproof and airtight, and recyclable. Wouldn't that be a better choice than plastic? Edit: thank you for your responses! I have begun a low waste journey, switching to solid bars wherever possible, reducing & reusing etc. I am trying to understand recycling and product packaging better, hence the question. Thanks for your help | Chemistry | explainlikeimfive | {
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"Those cartons use a material called Tetra Pak that’s patented so it’s more expensive than plastic bottles. It’s also harder to recycle than a generic plastic bottle. If you want to be more environmentally sound use solid bar soaps and shampoos.",
"No, its NOT carboard. The carton boxes are a mix a plastic and paper, the inner most layer is a sheet of plastic which is why it doesn't leak over time when you put in water (properly manufactured shouldnt leak)",
"As a general rule of thumb, the best thing you can do for reducing the environmental impact of something in production and transport is to lightweight, to use less. If the cartons weigh less then yes, you could say better on some metrics. However, recyclability is a lot worse. So I would question your use of better first, as it depends. Those kinds of products are, for the most part, made from a plastic that has some value as waste (usually PET or HDPE, sometimes PP) and so is often collected, and thus has a higher chance of being sorted and recycled. It is also easier to do this being a monomaterial (made of one thing) rather than a multilayer (cartons - cardboard, plastic, aluminium) package, which add complexity. Something to consider is just because a material has a property, does not mean we have the systems in place to deal with it. That is a big part of why we struggle with plastics currently, though the situation is improving.",
"Look into solid shampoos. They look like bars of soap, and they last a long time. We've been making this switch slowly in our household",
"Won't the outside of the box get all soggy and come apart?",
"Plastic bottles are not worse than Tetra pack. They are a single plastic type and could be easily recycled. Tera pack as a mix is much harder. You can even make them resusable and refilt them",
"No, they are not recyclable. Those boxes are a mixture of plastic, aluminium and cardboard, all bonded together. There's no way to separate that mess, so all of it has to be disposed of. The aluminium even means that it's not good to burn for energy production. If you ignore that and assume that pretty much no plastic gets recycled - unfortunately, a fairly safe assumption in most places, then it is good that it does use less plastic and more paper, but that's all there is to say for it. The biggest downside is higher cost - they take many steps to produce - forming the multi-layer board, printing it, folding and gluing/sealing it, moulding the multi-piece closure, attaching it - which adds to the cost.",
"Tangential, but there should be “refill” stores for shampoo, liquid soaps, etc. Plastic is designed to last forever, so let me just reuse the existing bottle. Charge per ounce or whatever."
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n7kybx | What does it mean to "own the float" in regard to stocks? | Economics | explainlikeimfive | {
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"Some wrinkle brained ape will explain this better, but I’ll give it a shot. When they own the float, they are talking about the shares that investors like you or me can buy. This is nothing exciting until you add in the naughty things the hedge funds have been doing. Very simply put, hedge funds have been selling shares that they don’t own. So many in fact that if they were ever ‘forced’ to give these real shares the the people that bought them, they would have to buy 1.7 times or more of the total float (depending on how naughty they have been selling fake shares). So imaging you have 10 bananas, and the hedge funds (HF) only have 3, but own someone else 15 bananas. They will give their 3 away, pay you basically whatever you decide to sell your 10 bananas at, plus they have to rebuy 7 more bananas from the person they owed 20 bananas to, and give them back. And that’s if you even want to sell them. You might like the stock (company), and bot want to sell. Now it’s all much more complicated then that, as the hedge funds were actually shorting the stocks, and strong evidence they have been trading off market to manipulate the prices of the stock. It’s a very interesting rabbit hole to go down if you join the superstonk or other group and read some due diligence (DD)."
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n7l08o | Why can't/won't car manufacturers make more cars of the older popular models? | Economics | explainlikeimfive | {
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"Old car models had a lot of problems that have been solved by modern designs. Weight reduction has increased fuel efficiency, crumple zones and frame geometry has increased safety, larger sizes were shrunk to decrease cost, etc etc.",
"Because older models may or may not be compliant with current rules. Things like safety, emissions, fuel efficiency etc.",
"They aren't that popular. They are popular in a niche. Sure, they could sell a few hundred or a few thousand of them. That would be easy. But they would need to re-develop the production lines and tooling to build them, which costs lots of money. They would need to meet current regulatory standards for safety and emissions, which, again, would cost money and may change the characteristics of the car. When you're working in mass production, changing things is extremely expensive. A mold to make a single plastic part may cost $1,000,000 or more. Running the machine may not cost much, but if you're only making, say, 5,000 parts with this mold, that mold has cost you $200 per part (Plus setup and operation costs too!). And there are many of these parts in a car. They would need to start a new production line to build the old engines. They would need to make every plastic part - just for this one car. Rather than using a part for 8 different car models, they would use many unique parts for one car. Cars that sell in small volumes tend to cost significantly more for what you're getting than cars that are sold in large volumes. One way to keep those costs down is to share parts across models. An old car design sold as new? It probably couldn't be sold at a price low enough to make money! One reason why every brand re-uses so many parts across all of their cars is because it is incredibly expensive to not do it. Even BMW does it. Audi does it. When you don't do it, you get to see prices like Rolls Royce. That R34 won't be very popular when it costs more than a new GT-R to make!",
"Because I have a 2018 Altima that gets better gas millage than my brothers first gen prius on the freeway..... Cars rapidly improve their tech. Plus part of the reason older cars like the R34 are in demand is because of media appearances and more than anything RARITY, you remove rarity you remove the value.",
"If the demand was really that high they wouldn't have stopped making them in the first place. Besides, they got rid of the equipment that made the parts.",
"Imagine how cheap cars would be if they reproduced the same model rather than came out with a new one every year.",
"The governments are constantly changing regulations on motor vehicles regarding things like safety and fuel efficiency/emissions so the cars have to keep improving, the demand for old vehicles is relatively small compare to the millions of mass production cars being sold so manufacturers develop new cars to meet the requirements.",
"In Europe, that does happen: Peugeot 205: [ URL_2 ]( URL_1 ) Production: 1983–1998 ... 16 years in production, with only some plastic strips changed. Volkswagen Up!: [ URL_0 ]( URL_3 ) Production 2011–present ... so already 10 years in production, only with a facelift.",
"Legality/regulations aside, a new Nissan R34 GTR was about 45k US which is about 70k US today. I'd imagine it would cost Nissan double to reproduce it vs the original mass produced price so that makes it a $140k car. Can't think of many cars where retooling a whole factory would make any financial sense. Aston Martin have done some continuation models of their old cars but they are hand built and cost millions.",
"Because cars like WV Beetle would not be legal to produce nowadays due to too much emissions, lack of safety features such as airbags etc.",
"Because they apparently don't want my money now that I'm older and can afford it, because if Mazda put out another RX7 FD I would have to buy like two of them."
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n7l2hd | How does underwater torpedoes propell and explode to cause maximum impact? Doesn't water extinguish the flame? | Technology | explainlikeimfive | {
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"Premodern torpedo. Torpedo hit your hull, the detonator detonates the giant payload (either by contact or prox fuse) the BIG CONCUSSION hopefully breaks a hole in your hull, and you leak. This is much much less effective because you rely on flood to sink, its why you see ww2 ship sinking only after multiple torpedo hits. Modern torpedo. Big explosions, BIG FKING EXPLOSION under the ship. and when explosions happen, it displaces the water. Here's the thing, most ships will break on land, because ships are designed to have buoyancy in mind to support the ship's shape. If there is a giant ball of nothingness and the bow and stern are still held up by water, the excessive weight (especially when majority of the weight is centered in the middle section of ship) will literally break the ship in half. And obviously post attack ship sinks. & #x200B; Neither method actually produce a high chance of fire. The only possible event for a torpedo caused fire (direct) is for a torpedo to strike a ship, penetrate the ship's hull, gets lodged, explode. But if the hull is so weak that even torpedo can penetrate it. the explosive will very likely just turn the entire ship into smithereens.",
"The explosion is a chemical reaction and doesn't require oxygen from the surroundings to create, by having the explosion taking place next to the hull of the ship the water pushes all of the force of the explosion into the ship rather than letting it dissipate, once the explosion has happened there is very little direct reaction from the explosion the water will \"extinguish the flame\". However the explosion may have caused other fires to break out in stored ammunition or fuel or oil for the engines.",
"Torpedos do not need air to get oxygen as they carry their own oxidizer supply both for the propulsion and in the explosive. And when they explode the purpose is not to set the other ship on fire. However it is to damage the structure of the other ship causing it to get huge openings in the hull to let water inn.",
"Depends on the torpedo, some chemical reactions used make oxygen from the water. When It hits it's target (either electronically or magnetically detonated) it the explosive makes a shock wave, which is what causes the bulk of the damage",
"It is kinda like a bullet with a propeller. The explosive is contained in the torpedo. If water has got into either one if them, they might not work or malfunction.",
"The explosion is not a 'flame'. It's the chemical reaction of the explosive elements being ignited. This ignition generates rapid expansion of gases, and this expansion generates a shock wave in the surrounding water. It's the shock wave that generates the most damage."
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n7lj1m | What is a "venture capitalist" and what is "seed financing"? | Economics | explainlikeimfive | {
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"Someone who invests in a small growing company with lots of potential, but not much of a track record. About 2/3rds of these companies will fail and the person will lose most of their money, but the others have the potential to grow into global companies worth many millions."
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n7n33s | Why was the atomic bomb just not destructive enough? why did we need thermonuclear | Other | explainlikeimfive | {
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"The problem with a fission bomb is that you are limited by the speed of the chain reaction. Not by it happening too slow, but by it happening *too fast*. So, to have a good chain reaction we need a fissile material compacted densely. But obviously that's the opposite of a what an explosion is. So your yield is limited by the fact that the plutonium core will rip itself apart before it has all had time to get in on the fission chain reaction. You can mitigate this by using heavy fissile materials as a damper to hold the core together for just a millisecond longer and increase the yield dramatically, but that doesn't compare to what you can accomplish in terms of destruction by going thermonuclear, using the initial plutonium core to start off a fusion reaction. The key here is the staging: you don't need to solve the problems of scaling up the primary fission reaction if what you're doing is using the energy of the primary to start the secondary reaction. (And then you can use that energy to start a third stage of fission, or a third fusion stage, or more... leading to theoretically unlimited yield if you chain enough together).",
"Short answer: The Cold War. The USSR and the Western powers were in a race to prove their superiority of their vision of society. Part of that would be to defend themselves, partly to show their technological capability.",
"The atomic bomb was (partially, very slightly) defeated by a hill, and to be clear that was after specifically picking targets with a minimum of hills. A bomb that can't be defeated by inconveniently placed landscape is a much better deterrent, and scaling up a fissile-only bomb is *much* harder, more expensive, and will cause more radioactive fallout than switching to thermonuclear designs.",
"The development of thermonuclear weapons was not solely to make bombs *bigger*. Early bombs were inefficient, dirty, and huge. Boosted fission is better, but thermonuclear is the logical next step. You can make a bomb *tiny*, but much less dirty and the same or even more strength. Smaller and more efficient bombs has really been the main focus of nuclear development. Make them harder to shoot down and easier to make. The fact that they *can* be bigger is actually mostly useless. It's the reason that the tsar bomba was little more than a publicity stunt."
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n7n80v | Inductors - how does it store energy in its magnetic field? | I'm currently studying inductors atm and from what I understood regarding inductors, when current flows through them, a magnetic field forms. And this magnetic field, in turn, would act as some sort of force that will keep the current flowing when the battery is removed. But it seems like there's something wrong with my understanding. I keep thinking that the magnetic field acts as a voltage that will keep the current flowing. But at the same time confused by the definition that inductors stores electrical energy in their magnetic field. This definition makes me think that the energy stored in this magnetic field created during the time that current flows through the inductor is the one that is used so that the current would flow after the source is cut off. If that's the case, how is energy stored in its magnetic field, considering that it will be used later to keep current flowing? | Physics | explainlikeimfive | {
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"Electric energy is stored whenever there is a voltage. but the energy is not the voltage itself, but the electric field that holds the energy. electric energy is released when you allow a current to flow. similar, the magnetic field can hold energy. You could name it \"magnetic energy\" if you like. magnetic flow is released whenever a current wants to change. both, electric and magnetic field, are the different parts of the electromagnetic field. There are other modes of enrrgy stored in the electromagnetic field, e.g. light."
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n7njof | why is the tower of babel so widely translated? | Other | explainlikeimfive | {
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"Because it's part of The Old Testament and the abrahamic religions (judaism, christianity and islam) are widely followed all over the world."
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n7np7m | The desire or distaste for drinking plain water | Biology | explainlikeimfive | {
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"Desire: your body is made up water (~60%). Water is needed to maintain your bodily fluids which in turn keep you functioning at an optimal level. Water is essential for humans. Dislike: Environmental impact; you have been accustum or exposed to too many bevarages. Thus, your desire for consuming drinks that have 'flavour 'and a' kick', which in turn results in you disliking water. That's my two pence....",
"Depending on where on the planet you live, different methods for cleaning drinking water are used. On top of that, different soils and pipeline materials,etc can also change the texture, acidity and flavor of plain tapwater. Some regions have a lot of calcium in the water for example, which makes the water feel coarse and taste a bit more bitter."
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n7nszp | why do our eyes burn when we're tired? | Biology | explainlikeimfive | {
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"One of the things we do when we are preparing for sleep is we start producing less tears, because we are expecting that our eyes will be closed and we will not need to constantly lubricate them as much. So if we force our eyes to stay open when we are tired enough that our body is going ahead and starting the shutdown process, our eyes get dry very quickly."
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n7o4ij | Is there a difference between the different types of toothpaste? What makes them different from the rest of the schmucks there? | Chemistry | explainlikeimfive | {
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"I used some with diatomaceous earth to polish scratched DVDs back in the day...I had to try several different types to get a nicely fine abrasive. The gel ones weren't useful for DVD polishing but if you're on top of your teeth brushing they could be the best. Some have hydrogen peroxide. I've been swishing a bit of 3% hydrogen peroxide every other day and my dental checkups have been superb! (unlike before) So, I like the H2O2 but question the strength / persistence if it's in a toothpaste... also, I'm told you only need to use way less paste than is shown in ads - just a pea-sized blob, not an inch long worm...",
"I read somewhere that brushing does most the work. But I'm not a dentist. Brushing supposed to break up colonies of bacteria same with flossing. So I'm not sure specifically about the toothpaste . I look forward to the other answers."
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n7p9ze | why does the weather forecast sometimes put the chance of perception lower than 100% when it's already raining? | In this case I'm talking about hourly or current forecasts. Occasionally I see the hourly weather forecast show 70% or 80% chance of precipitation when it's been raining the whole day and the Doppler radar shows no chance of it letting up within an hour or so. Why isn't it then 100%? | Earth Science | explainlikeimfive | {
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"It is shorthand for \"percent chance of precipitation in the (viewing) area over the course of the prediction period.\" From the National Weather Service: “PoP (percent chance of precipitation) = C x A where “C” = the confidence that precipitation will occur somewhere in the forecast area, and where “A” = the percent of the area that will receive measurable precipitation, if it occurs at all.” So if they're working with a bigger area (say, all of upstate NY) vs. a smaller area (Manhattan, for example), they're going to be less accurate for your specific body space. And if the weather is more variable or erratic, the chance will go down, as well.",
"The percentage you are seeing isn't actually \"percent chance it WILL rain\" but rather \"percent coverage of rain in a given area.\" If you think about it like if an area is 4 boxes, and there's a 75% chance of precipitation, then 3 of the 4 boxes are going to get rain. Essentially any time you see even a 10% \"chance\" of rain, what they really mean is 10% of the area IS GOING to get rain, and if you're in that 10% then you're DEFINITELY getting rain. Does that make sense? Worded differently, \"if there's a 10% chance of rain what it really means is there's a chance I'm in that 10% of the area that will get rain.\" On the opposite side, if there's a 90% chance of rain, it means 90% of the area you live it will get rain, and 10% is not. Unfortunately I don't fully understand how large an area or what parameters they use to decide what percentages to use, hopefully someone else can explain that further.",
"Its not a measurement of chance of rain in that entire area. It's a measurement of what percent of the total area will receive at least some rain ( > 0.01 inches) Its called Probability of Precipitation. So while your location might get rained on the whole time, some other part of the coverage area probably isn't unless the PoP is 100%",
"It might be raining directly over your head, but 5 miles away, still in the service area of that particular news outlet, it might not be raining. In which case the individual chance of being rained upon is still less than 100%."
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n7pbfw | Why would my allergies be much worse this spring? | Biology | explainlikeimfive | {
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"We have just spent a year outside wearing masks. So we spent a year breathing in less allergens. They are just making up for lost time",
"Hard to say without knowing where you live. Usually the prime suspect is rainfall leading to more plants."
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n7qea8 | I see a hotsauce on a shelf i have never seen nor mention nor searched before. Go home and for the first time get an ad for it. | Other | explainlikeimfive | {
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"basically whenever you use a service from a big data player (google, apple, amazon etc) every bit of data that could be harvested, is harvested. then it takes a fun journey throu data aggregation algorithms, machine learning and classification, so in the end even if noone has the information that you just used the service to do something, the information of \"people that are similar to you do that particular thing\" is kept. so the next time the ad reccomendation algorithm sees you, being you very similar to yourself, it knows that probably an ad about that thing is effective on you."
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n7re15 | Why do Humans find smiling , showing teeth attractive, but is a threat gesture in apes and other animals? | Biology | explainlikeimfive | {
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"The leading theory is that it is a paedomorphic characteristic of humans, which basically means that it is a characteristic only found in the young of other species closely related to us but that we retain into our adulthood. Among chimpanzees and gorillas, the young will commonly show their teeth when they want to initiate a play fight. And this is generally regarded by adults as non-threatening and even cute, since it's signals a desire for a pleasant form of interaction. One Way or another, we humans ended up keeping the young eight interpretation of this gesture even into our old ape years.",
"Not a complete answer here but it is worth pointing out that Humans show their teeth to express a number of emotions, not just to smile. Pain comes to mind...",
"Why is this posted in some form or another every week? Karma farming?"
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n7rpur | Why is it more common to eat unhealthy than to eat a balanced diet? | Other | explainlikeimfive | {
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"Humans are animals whose biology evolved over time in environments of scarcity. Over time we developed specific rewards systems to ensure we seek the right type of nutrients. We developed different tastes because, in a survival frame of mind, it is much more important to consume enough daily calories to run your body than it is to meet your daily vitamin and mineral requirements. This is why people love fats and sugars, fat has more calories than carbs or protein, and sugar/carb calories are very easy for the body to use. Now that humans have created a civilization where some of them can purchase varieties of food they want, whenever they want, it can be difficult to restrain those primal survival instincts to consume as many calories as you can while limiting your expenditure of calories. This somewhat explains why eating disorders and substance abuse are so common. We have rewards systems in our bodies meant to ensure the survival of the species, and those things that make our bodies feel best are the hardest to protect ourselves from. It's the same rewards systems that social media and video games try to take advantage of to keep you engaged.",
"In my, non profesional opinion, it’s due to ease of access and cost. It costs $1 to get a burger or chicken nuggets versus $12 for a salad and a bottle of water. This applies to food that you would make for yourself as well. Ready to heat meals are cheaper but loaded with sodium.",
"Our brains are wired to enjoy certain nutrients that are uncommon, since long ago, we might not come across them again for a while. A good example of this is raw sugar, or anything with high levels of sugar. Our brains say \"stock up we might not see this again\" And food companies have cashed in on this biological happenstance by making their food really high in sugars (or other rarely naturally occurring nutrients). So even though we have lots of access to a nutrient oir brains are worries we won't."
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n7rs54 | What does unironically mean and how do you use it right? | I'm a bit lost on what it means. It's better if you explain to me like I'm an actual 5 year old. | Other | explainlikeimfive | {
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"Ironic definition: \"happening in the opposite way to what is expected, and typically causing wry amusement because of this.\" So for example take modern trends. I'll use the word \"simp\". A lot of people use the word simp simply because it's a meme/joke today. But if you were to call someone a simp without meaning it to be a joke but actually calling them a simp, you would be using the word unironically.",
"The prefix \"un\" means \"not\" (more or less), so \"not ironically\". Irony is a form of satire in which you say one thing in a dramatic or exaggerated way to indicate that you actually mean the opposite. \"Oh boy, I **LOVE** when people cut me off in traffic!\" Is an ironic statement. I emphasised the part to be thought of in the opposite way, and no one loves being cut off in traffic. Synonyms for \"unironically\" would be sincerely or seriously.",
"When you unironically like something, it means you genuinely like that thing. The best examples I've heard is in the context of \"so-bad-it's-good\" movies (where you usually like the film ironically, because it's so terrible.)"
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n7ryg5 | Which point on earth is the most remote and far from civilisation on land, besides Antarctica? | Earth Science | explainlikeimfive | {
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"Tristan da Cunha, a series of volcanic islands between Africa and South America - URL_0"
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n7s4lu | How and why do mirrors facing each other create an infinitely repeating image? | I'm genuinely perplexed. How does the reflection create another reflection, create another reflection? | Physics | explainlikeimfive | {
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"When light strikes a mirror, all parts of the light spectrum are reflected. Most surfaces absorb light and only reflect back certain portions of the light spectrum (a red apple absorbs all light expect red; red light it reflected back giving the appearance of a red apple). Since mirrors reflect back the full spectrum, you are able to see yourself in the mirror. If you put two mirrors facing each other, the light bounces back and forth between them."
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n7s7zl | When you open a tap, why does the flow of water near the top seem more orderly, while that near the bottom is more chaotic? | Near the tap, the water emerges as a column, but at the bottom, it looks like it's been twisted. Why is this so? | Physics | explainlikeimfive | {
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"Capillarity. A blob of water tends to become a spherical drop because its surface acts like a rubber film trying to squeeze it together. The water out of the faucet is practically in free fall so the tiny capillarity forces can break it up into individual drops (minimizing its overall surface energy). You can watch videos on YT about how water behaves in the ISS without gravity. Back on earth you can see it best when the flow is just a tad over that of a dripping faucet: the small water column will soon break up into separate drops."
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n7tdes | Why does extremely old footage appear to be sped up? | Watching old footage like from the 1920s appears to be going at 1.5X. Why is this though? | Technology | explainlikeimfive | {
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"As others have said, there wasn't a standardized frame rate (24 frames/sec) until the mid-20s. The illusion of movement happens as low as 15fps, so cameras, early on, filmed anywhere from 15-30fps. So footage that was filmed at 15fps and projected at 24fps suddenly looks sped up. **But they were never meant to be seen that way. Whoever transferred them screwed up.** Every silent film we have ever seen was a transfer onto 8, 16, or 35mm, done 50+ years ago, as cellulose nitrate film aged incredibly poorly; it became brittle and combustible (hence, less than 10% of all silent films made exist to this day). They burned like a modern-day Library of Alexandria. If they were originally transferred at the wrong frame rate, that is the only way we have ever known those films to exist and the originals were destroyed so it can never be fixed properly. After 10, years I finally got to use my degree. Thank you for asking. Edit: Yes, changing the framerate is very easy in the digital age. Every film could be corrected in speed as frames were transferred 1:1. 75+ years of silent film played too fast has changed the language with how we perceive it (i.e. it may look unnatural to us if it were corrected). It is a major part of the history of film and I think distributors choose to leave it as a document.",
"As far as I’m aware it’s for two distinct reasons: 1. The frame rates of the cameras were incredibly low and when played back on devices with a much faster frame rate, it speeds everything up. 2. Also there was a period of hand cranked cameras being the standard, so controlling the speed was down to humans which is another reason for sped up and inconsistent footage. I’m not sure if the two reasons can both be applicable to the same footage but if so that would probably explain the most extreme examples.",
"The frame rate was slower (18fps). When it’s played back on newer equipment it has to match the frame rate for now (24 or 30fps)",
"The Peter Jackson WWI documentary has a whole section on this and how they compensated for it. It’s fascinating but also really brings the reality of those boys at war to life.",
"Extremely old footage used cameras which were hand cranked so the cameraman could change how many frames were shot per second by changing the speed of cranking, so when they are replayed at \"normal\" speed the people appear to be moving really fast."
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n7u8e0 | why do we have to preheat the oven | Other | explainlikeimfive | {
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"If you put the food in there before it's hot enough to actually cook the food, it will be sitting in a mildly warm box for like 5 minutes just drying out before the cooking process even starts."
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n7udl8 | Why do some injuries hurt at the moment of impact while others hurt the day after? | For example let's say you fall and you can't move for a a few seconds because your knee really hurts, peter griffin style, but the next day what really hurts is like your back or your shoulders. Why is the pain at that moment so sudden and goes away quickly while the other will come a while after? | Biology | explainlikeimfive | {
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"There are two types of pain: * an immediate severe one to make you escape closest danger (e. g. you'll reflexively remove your hand from a flame or a sharp object); * afterwards a different, long-lasting, deep ache if you have been seriously hurt. Its function seems to be to send you (or any animal) into a safe place to heal, and also to limit exercise while getting better."
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n7v3lk | how was child labor deemed acceptable by society? | Other | explainlikeimfive | {
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"Because it was better than starving. As horrible as poverty is today in the industrialized world, the poverty that people experienced in the past was almost unimaginable. It was work or starve. The worst of the capitalists just don’t care about anything but their wealth and power, and they had plenty of both. It took a socialist/labor political revolution to avoid a literal revolution, and get the government to intervene by enacting labor and welfare standards."
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n7v4su | how/why does the loss of one oxygen atom from CO2 (thus turning it into CO aka carbon monoxide) cause such profound differences in effects on human biology? | basically the title. i’m sorta new to reddit, never posted here. i flunked chemistry and only a decade later am i finding that it’s actually incredibly interesting now. i guess i was just a dumb kid who bloomed late lmao. so i sincerely apologize if this is a dumb and/or annoying question. see the thing is, while i probably need to be eli5’d, i also reeeeally appreciate detail, lots and lots of detail and getting real in depth about this kind of stuff. ironically, despite the almost complete lack of any useful chemical knowledge (HS edu was a basically joke for me, but i’ve been reading a lot of chem stuff online ever since i rediscovered the wonders of math & chemistry a few days ago (literally)) i got a 3.9 in a biology 101 summer course (only taste of higher education i’ve ever had) and have been routinely reading about bio and medicine since, like, middle school, as a hobby and also bc studying medicine and pharmacology was, and continues to be, a long time dream of mine. so i know this question kind of includes a lot of elements (no pun intended-ok at least not initially) to it: chemistry, biology, human physiology, biochemistry, ?organic chemistry?, etc. this is probably a super PITA thing to say but can it be both eli5’d and then, if anyone is kindly willing, explained in much further depth? Or gimme some good, relevant links? btw: yes, i did in fact actually try to google this. i actually tried decently hard, but after 3 search result pages worth of carbon monoxide alarm ads, poison control center contact numbers, and not a thing to do with the chemistry let alone physiology of it, i gave up. i really do appreciate anyone who takes the time to bother with this question ✌︎︎ (⊃｡•́‿•̀｡)⊃ | Chemistry | explainlikeimfive | {
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"well I cant help too much on the chemistry side but can speak from a medical standpoint, see below. Stole this from a website: **Carbon Monoxide** (CO) is a chemical compound which contains one carbon atom and one oxygen atom and is also a colourless and odourless gas. Unlike CO2, it is entirely human-made and is not naturally present in the atmosphere. It is produced during the incomplete burning of organic matter, which can occur from motor vehicles, heaters, or cooking equipment that run on carbon-based fuels. CO is therefore spatially variable and short lived in the atmosphere, where it has a role in forming ozone at a ground level. When carbon monoxide is present in concentrations greater than 35 ppm it is toxic to humans and animals, as it prevents the blood from carrying oxygen. Rest of this post, is me: Medically how it prevents the blood from carrying oxygen is a fairly complex question, but ill do my best. Carbon Dioxide, which is naturally formed by our body, is actually only found in low concentrations in our blood. At higher concentrations in the blood it can be just as deadly as carbon monoxide. The vast majority of Carbon Dioxide however, is converted into carbonic acid which quickly dissassociates to bicarbonate (HCO3-) \\[not harmful\\] and a Hydrogen Ion (H+) using an enzyme called carbonic anhydrase. Where it is transported to the lungs or kidneys, where the same enzyme then converts it back to CO2 to be released by exhaling (CO2) or in our urine (as HCO3-) so it cant do any damage. In regards to the CO you need to have a basic understanding of how oxygen is transported in the body. In the most basic form, we breathe in oxygen, the high concentration of Oxygen in the air we breathe causes previously bound CO2 (relative small amounts of actual gas) to be released by hemoglobin (a protein in red blood cells that carries oxygen, CO2, and few other gases) and the oxygen (usually a few molecules for each hemoglobin protein) takes its place and is transported around the body to where it is needed. The body knows where the oxygen is needed because there will be a high concentration of lets call them activity markers (basically molecules showing cells are doing work....H+, C02, etc). This high concentration of activity markers tells the hemoglobin to release the oxygen to that area, because oxygen is needed for the cells to continue their work. THe CO2, H+ etc is then picked up and headed back to the lungs / kidneys and the cycle starts over again. Carbon Monoxide is an issue because when in the human body, it not only binds to hemoglobin (like oxygen and CO2) but has a stronger affinity (wants to stay bound) to hemoglobin. Therefore when in the human body, the carbon monoxide binds to hemoglobin and stays strongly bound to it preventing oxygen from being bound (at the lungs) and released to where it is needed (legs, brains etc), so the body doesnt get the oxygen it needs to survive leading to first confusion, blurry vision, headaches, vomiting etc, then loss of consiousness and eventually death, unless treated. In the simpliest of terms, Carbon Monoxide itself doesn't do damage, it just prevents the human body from getting the oxygen it needs. vs. Carbon dioxide, which is naturally found in our body, and therefore has multiple methods of getting released OUT of the body, but technically in high enough concentrations can do the same thing.",
"Because different combinations of molecules have different shapes (which affects where they can \"slot in\" to large molecules\") and different charge distribution (which affects where on the molecule and how strongly they will repel/attract/give/take/share electrons). CO and CO2 will interact with complex molecules in very different ways. This goes for a lot of similar molecules with single-atom differences, for example Water vs H2O2 (one necessary, one toxic). For the specifics of why carbon monoxide is lethal, its structure and charge allows it to bond to hemoglobin (the oxygen carrier in your blood) just like oxygen would. However CO bonds about 200x more tightly than oxygen and is harder to force out. You'll suffocate breathing in CO as your blood will start carrying that around instead of the oxygen you need. Our body does have some systems in place to enforce our breathing instinct and prevent suffocation normally; however, these systems are all wired to trigger when you hit abnormally high blood CO2 levels (and therefore low oxygen). Since CO does not interact with those detectors the way CO2 does, if you're suffocating on CO, the \"need air\" instinct will never kick in, and the oxygen loss can make you sick, cause brain damage, or kill you before you realize what's happening."
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n7ve69 | Why does oil not evaporate like water does? | My face gets really oily and when I touch my glasses in the morning (8 hours since warring them) the oil hasn't evaporated like water would have. Does it just take really really long to evaporate? | Chemistry | explainlikeimfive | {
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"Yes, it takes a long time to evaporate. Oils are usually comprised of very big, rather heavy molecules, which is most of the reason that oil is liquid to begin with. So oils have high boiling points/low vapor pressure compared to water, but oils don't have *no* vapor pressure. Other organic molecules miscible with oils but closer in size to water molecules, like acetone or ethanol, have much much higher vapor pressures and evaporate even more quickly than water.",
"1. Something boiling/evaporating means its individual particles flying out of the liquid into gas phase. Different things have different boiling points - it's determined by what forces are present within that liquid. If the particles like sticking to each other, it takes higher heat to make them fly apart (aka evaporate). 2. Liquids evaporate when the temperature is above *or close to* their boiling point. Some evaporation happens *below* the boiling point because \"temperature\" is just the *average* speed of particles. Water boils at 100C, but water at 90C has quite a few individual particles moving at 100C-speed, and those are the ones that fly off and evaporate. That's the steam you see! Room temp water evaporates because even at \\~20C, there are a few particles that reach 100C-speed and fly off. **TLDR**: Every liquid has an \"escape speed\" needed for particles to fly off and evaporate. The further below the boiling temp it is, the less likely its particles are to reach escape speed. The result of 1 & 2: * Some things have lower boiling points than water, like acetone (nail polish remover, boils at 56C). They evaporate faster than water does, maybe you've experienced this? It's because acetone molecules (particles) don't like sticking together as much as water does. * Some things have higher boiling points than water. Their particles really like sticking together. Eg olive oil boils at 180C. * Net result: The oils on your face are much farther below their boiling point than water is, so they \"don't\" evaporate. (actually they do but very very slowly, everything does). Bonus: Solids are just things whose molecules like sticking together even more than liquids do. Every material has a melting point escape temp/speed too, and all the logic I said for boiling/evap above applies. **TLDR 2**: Oil doesn't evaporate for the same reason a pile of coins doesn't melt. The temp isn't hot enough to get the material in question to stick to itself less."
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n7vod4 | why do costumes cost more money than regular clothes despite using seemingly cheaper fabrics? | Economics | explainlikeimfive | {
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"Because costumes are specialized equipment that is produced in significantly lower numbers than regular clothing and the demand for specific costumes has a *very* high variance. The materials used in a product have almost no bearing on the eventual price. That's mainly determined by demand and supply.",
"Because people will pay more for costumes regardless of the materials used. That is all there is to it. Production costs, delivery costs, etc don’t figure into the final price of this product at all.",
"Smaller market so smaller runs means higher expense per item, so to keep the same margins, higher prices.",
"It is easy to make 10,000 copies of the same item of clothing therefore it is far cheaper, smaller runs or individual runs are far more expensive.",
"I'd also like to add that some of the sewing techniques for costumes can be challenging and have to be done by hand thus up-ing the price."
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n7wt1o | Old cities have been excavated that are covered in soil from years of neglect/abandonment. Sometimes from quite deep underground. Where does the soil come from? | Earth Science | explainlikeimfive | {
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"There are a few different things, all of which may or may not be present in any given site: 1) Rivers naturally deposit silt along their riverbed, slowly becoming shallower until they spill over into a new area and change course. When humans are living next to a river they will actively manage that river's course by building dams and levies, as well as periodically dredging it to prevent silt from building up. If humans abandon a site, or the humans living in a site experience a period of economic hardship such that they aren't able to repair levies or dredge the river for a period of time, then the river will eventually change course, potentially flooding and/or burying the city in the process. 2) Buildings will slowly sink in dirt and continue sinking until they hit bedrock. The speed with which this happens depends a lot on the local ground conditions and the quality of the building's foundation. Premodern buildings tended to not have very good foundations and there are lots of regions in the world with muddy soil that buildings can sink into over the course of a human lifetime. Historically, humans that were maintaining buildings in high subsidence areas would periodically knock them down. They would then use the rubble from the old building as a foundation and build a new building on top of it. However, if humans abandon the building then it will just continue sinking. Over very long periods of time this can result in the building sinking completely underground. 3) Huge quantities of dust gets blown off the Sahara and Gobi deserts every year. This dust gets deposited in nearby areas and can build up quickly. This is a particular issue in areas like Egypt, Greece, Turkey, and parts of China. (Note that those are also all areas with large numbers of well preserved, buried buildings). As with everything else, if humans are actively maintaining the area then they will clear that dust away or rebuild the buildings in the area on top of it. Once humans abandon the site, however, they stop doing that and buildings can very easily be buried. This is especially true as buildings act as a windtrap and so a lot more dust gets deposited on them than gets deposited on the surrounding area.",
"dry dust blown in from the wind mixed with water from rain and nutrients from decaying life creates a layer of soil over long periods of time"
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n7xbdg | The “Impossible Colors”, we can’t we see them? E.g Redgreen, or Blueyellow? | Other | explainlikeimfive | {
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"humans have two main types of light sensing nerves rods and cones. rods are most sensitive to a wavelength between blue and green (495nm) but are percieved as grey. rods are most sensitive to low light and are smallest so can provide higher resolution than cones. there are three types of cones that are each focused on a different range of wavelengths: red (560nm), green (530nm), and blue (430nm). the problem that leads to impossible colors stems from the fact that these colors overlap... particularly red and green are very close. this means that in normal life it is not possible to trigger red cones without at least partially triggering the green cones. so impossible colors include things like the color you would see if it were possible to trigger your red cones without triggering any green cones... it would be \"redder\" than any physical object can be. :)"
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n7xojf | why does Pepsi in a can taste different from Pepsi in a glass or plastic. | Chemistry | explainlikeimfive | {
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"The aluminum cans have a polymer lining that can absorb some of the soda’s flavors, potentially making the taste milder. If you are slugging your soda from a plastic bottle, the soda’s flavor may be altered by some of the acetaldehyde in the plastic transferring into the drink. Since glass bottles are basically inert, they’ll deliver a product very close to the original intent. The metal taste some people note from soda in cans may have more to do with their sensitivity to metal—they’re tasting the can as they put it to their lips, not a metallic taste that’s actually present in the cola. Edit: since this has taken off I want to make sure the source is given credit, I shamelessly copied from [this Reader's Digest article]( URL_0 ) Also if anyone wants to learn more, [Nilered made a video]( URL_1 ) where he isolated the chemical responsible for the \"old penny smell\", which is a deep dive into how we perceive metal.",
"I’ve learned (from a local brewery) that cans are the best way to package drinks because they allow no light to effect the product. And the metallic taste comes from the smell of the can - if the liquids were poured into a glass to drink they would taste the same ( or the can would possibly taste better if the plastic/glass bottle was exposed to too much light) Think about it like a tiny keg of beer.",
"Is it same for beer/alcohol? I'm not a drinker but my friend who is claims it tastes better",
"i work as a quality analyst in a worldwide beverage company so i think i could give you some insights on why the beverage tastes different in different packagings. to some of you who think it's placebo, it's actually not. the flavor is basically affected by the amount of CO2 present. One of our quality release criteria is the gas volume- the amount of CO2 present in the bev and we set a certain range, rejecting those products that fails or exceeds the set limit. Glass and aluminum cans have lower porosity. This makes the 2 as good packaging materials since it helps retain gas volumes in soda. in other words, glass and metal prevents the CO2 from \"escaping\", maintaining the fresh biting taste. On the other hand, plastic/PET bottles have higher porosity than the 2, which means CO2 can easily escape making the soda bland. To compensate this difference, we deliberately increase gas volumes in PET products. fresh bottled PET sodas have very strong \" bite\" due to high volumes of CO2. Also, you can confirm this by their expiry. If you notice, glass and metal packed beverage have longer expiry dates that PET ones. In bev industry, expiry is not determined by flavor going bad but by CO2 retention. Since glass or metal can retain gas better they can last up to1 yr whereas PET only can last 3 to 6 mos. Other factors affecting taste are trace iron in crowns/caps, trace acetaldehyde in PET and oxidation (prolonged direct sunlight exposure).",
"The material can play a part, but if your pour canned soft drink into a glass it can sometimes taste different. This has to do with the aperture of the vessel. The shape and size can opening, straw, bottle or glass can direct the drink in a different way to your palate, which is why you have different glass shapes for various wines and whiskies and other spirits, etc.",
"You have some good answers, but another factor is that fizzy drinks may have slightly different recipes between plants, if nothing else they'll use different local water which will have different minerals and hardness etc.",
"I think before ansering the *Why?* one should answert the *Does it?* question. How sure are you, that the three really do taste different and not that either some other parameter plays a role here and you just attribute the difference, or - equally likely - that you *think* or even are *convinced* you taste a difference, but it's your brain playing tricks with you. To be sure, one would have to do a double-blind test. Have someone buy 5 cans, 5 glas bottles and 5 plastic bottles from the same store with the same best-before-date, essentially ensuring that storage conditions and duration isn't the blame. Then have them - without you seeing it - pour a glass of each in identical glasses and have them randomly arranged on a table. Remove all containers and let whoever did the pouring leave the room as well, after they created a 'map' of what was in which glass, which they of course take with them as well. Only then enter the the room and taste 11 of the 15 samples and sort them into category groups. Then check (using the mapping) how well your \"groups\" actually match the three containers. I would actually be a surprised if the match would be very good.",
"Fun fact, I used to work where the coating inside soda and soup cans is made. The main ingredient is tetramethylbisphenol F, we had to wear full face respirator and tyvek suits when we handled it. It can cause infertility",
"Growing up in the north east I remember pepsi products coming in glass 16oz bottles, they were in 8 packs . We would stick them out in the snow behind the house. Almost frozen mountain dew out of a glass bottle after sled riding... better than crack.",
"Pepsi only sells their syrup. Whoever bottles it, cans it, or dispenses it mixes the syrup with their choice of syrup/carbonated water ratio. Also, the material you drunk something from changes the overall taste too. For example, drinking Moscow Mules out of copper, etc.",
"So I know styrofoam is terrible for the environment but there's something mighty fine about a fountain Dr pepper in a styrofoam cup with ice. It just hits different.",
"Afaik this has been researched and it's all placebo. If they pour glass, plastic, and can into a cup and hand it to you people can't tell the difference. So it's the feeling of the material on your lips and the smell of the material that actually does it. The drink itself doesn't taste any different.",
"The answer to this is simply because of the different bottling/canning material.. goes for fountain drinks as well."
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n7xpj4 | How does orbital dynamics work? | Mathematics | explainlikeimfive | {
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"Things in space have an attractive force called gravity. In contrast to celebrities, things with more mass have a more attractive force. Between two bodies, based on their relative mass, there’s a center of gravity. Those two bodies orbit around that one point. When considering things with divergent mass, it appears as though one thing is orbiting around the other thing (Sun/Earth, Earth/Moon). Here’s the issue, that’s for a two body problem. There is no closed mathematical solution for a three body problem (ie Sun, Earth, & Moon). Everything is pulling on everything (just like celebrities). The orbit of the moon around Earth is affected by both the sun and Jupiter. Just to varying degrees depending on the time of year."
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n7y6jo | How do humans recall numbers like their SSN # or an old phone number after not thinking about them for months or years? | I just had to insert my SSN for a form, and it came back to me instantly. How is that possible when I forget so many other facts and numbers from both before and after learning that one? It's not just that the SSN is so important that I know I can't forget it; I, for whatever reason, also remember the phone number of a girl from my hometown in 3rd grade. Can't for the life of me recall my own license plate after years of having it. | Other | explainlikeimfive | {
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"The way we remmember things is with connections between the neurons. The more we do something the stronger the connections become and the easier the task gets. That's why you can be 50 and still be able to ride a bike. If you had to put in a phone number a lot then you still will be able to remmember it after big amounts of time.",
"So, coming from a special education point of view, numbers like that are \"chunked\", like your phone number. There is no reason to have dashes or break up the numbers, but they are broken up like that for memorization purposes. It's easier to remember small groups of numbers, rather than one whole large number. You can put put groups together later to create the whole number you need.",
"I think that things we memorized when we were younger stuck with us, especially something as vital as an SSN. I can't remember things now, but SSN and driver's license are automatic.",
"Iv noticed that a lot of younger people can’t. I think it’s because we had to remember numbers for different reasons when growing up. What was your childhood home phone number? Why was your friends phone number? We remembered those from constant repetition, nowadays we save the contact in our cell phones and that’s that. We used to fill our information, now smart phones remember it and do it automatically. I dunno, those are just my thoughts",
"I can't. I think it has to do with muscle memory for me; when I've punched in the same number on the same keypad every day for a long time, it becomes thoughtless. If I have to stop and think about it (I've had it happen after taking a week's vacation) then I'm totally screwed. Couldn't remember the number for the life of me. Had to look up my SSN after just 1 year of not using it."
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n7y785 | Why is it so important for people to wash their hands after using the toilet, but animals lick/clean their genitals and butt all the time with apparently no consequences? | Biology | explainlikeimfive | {
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"As with all questions about why animals \"don't\" get sick and die, the answer is: they *do* get sick and die, all the time. They get all sorts of parasites, bacteria, and viruses. Animals in captivity *generally* live longer than their wild cousins because, among other things, we give them antibiotics, and we keep them in a much cleaner environment. Humans are more concerned about avoiding death from pathogens because we have the capacity to understand Germ Theory *and* the tools to prevent it from happening. A deer with a rash on its taint may instinctually avoid licking that area *normally* but it doesn't understand *why* it shouldn't and that general \"don't tongue punch your own fart box\" instinct frequently gets overpowered by things like an insatiable itching. And then that deer gets a disease and dies. Or gets a disease that makes it too weak to run from a wolf and gets eaten. Either way, you aren't likely to notice the goings-on of random deer with a rash in the forest. The other concern is one of scale. An animal might lick its own hind-quarters and otherwise won't lick much else that it isn't either trying to eat or trying to prevent from eating itself - neither of which the animal cares about keeping healthy and alive. Humans touch *everything*. We touch doorknobs and steering wheels and keyboards and phone screens and our clothes and each other. We touch our hands and our genitals and our faces and our eyeballs and our mouths. Diseases end up with a lot more opportunities to get into our bodies from a lot of different places. We *very* often touch food that we are preparing for others. One exposure to diseases from our own b-holes doesn't stay with just us, it potentially exposes *many* others. The odds of any single person getting sick from wiping a dirty hiney are fairly low. But one person accidentally ripping through wet TP on their bottom who then goes on to prepare a salad for an entire restaurant spreads that one exposure to hundreds of exposures. Animals don't normally prepare food for others so *if* one gets sick like that if it dies, that's the end of it. It spreads a lot more slowly than it would among humans. Edit: also worth noting that since we understand Germ Theory and #weliveinasociety it's *polite* to wash. Even *knowing* that a person has no communicable disease we are disinclined to have their bodily fluids on our stuff. It's icky. Edit2: speaking of phones...if you're a redditpooper or just a general phonepooper, it's a good idea to disinfect your phone periodically with a Clorox wipe or something that won't damage your phone. [Phones are gross.]( URL_0 )",
"And to add to the started above… most of us can’t reach out bits with our mouth. Wouldn’t be able to clean yourself that way. 🤷🏻♀️ (i wouldn’t want to even if i could lol)"
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n7yv5h | How does ADHD contribute to low self-esteem? | Biology | explainlikeimfive | {
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"URL_0 There are various reasons. With ADHD having a profound effect on multiple domains, and this question is going to affect you differently at different stages of development. But if we look at youngin's, we see that their education is affected and so they aren't seen as (or perceive themselves) to be as smart. They may have fewer friends. And they are also often known as 'the naughty child'. The impact on self-esteem that has is obvious. (As an average and generalization, there will always be outliers and exceptions) That's before getting into other effects like having a diagnosis, having something 'wrong' about your brain and the way you think and behave, the core of who you are."
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n7z2j5 | if H2O(water) can be turned into O2(oxygen) and H (hydrogen) why can’t we just turn CO2(carbon dioxide) into O2(oxygen) And C(carbon) and slow down the greenhouse effect | Wouldn’t this just solve a lot of problems | Earth Science | explainlikeimfive | {
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"It's possible but we would need massive facilities all over the planet doing it in order to have any noteworthy effect, and it would consume massive amounts of energy, which in many places is still generated by burning fossil fuels and would cost a lot of money to operate, and most governments don't seem to feel the environment is a big priority.",
"if you burn coal you combine carbon snd oxygen and get energy out of the reaction. if you take co2 and you split them up you need to invest energy. best case, its a zero sum game and it would have bern better to not burn the carbon at all. in reality you would need to invest more energy into splitting up co2 than to fet by combining them. in essence, you would emitt 2kg co2 to split up 1kg of co2 ( only examplary numbers). to answer your question: it is possible but only makes sense if you use energy sources other than fossile. and even then it's better to not burn fossiles at all. if you had eccess energy (eg from solar) you could run carbon recapture machines and it could make sense.",
"The problem is that the concentration of CO2 in the atmosphere is so low. This isn't to say that greenhouse gases aren't not a problem; the levels of CO2 necessary to induce significant, severe climate change are also very low. But the low concentration of atmospheric CO2 means that you need to have either a lot of these facilities all over the place to sequester carbon everywhere (which would be very expensive to build and maintain them everywhere) or you need a lot of time for a few of these facilities to sequester the carbon (which we don't have, as climate change is already underway)."
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n7zdk9 | - What’s different between the same pasta shapes but one cooks in 5 minutes, the other in 10? | Chemistry | explainlikeimfive | {
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"The varying amounts of thickness and shaping affect the surface area and thus the cooking time - even size and shape with lots of surface area will cook faster. Compare spaghetti vs rotini for example.",
"Look at the actual ingredients. Two pastas that at first glance seem identical can be quite different. One is made with wheat and egg and the one with the longer time is usually the cheaper one made from Semolina (coarse, purified wheat middlings)"
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n7zk0a | Why does the body sweat when we eat spicy food? | I was wondering why the body responds by sweating and/or we get a runny nose when eating spicy foods? I know this isn't the same for everyone, please explain! Thanks | Biology | explainlikeimfive | {
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"Spicy food (more specifically the chemical capsacin) works by actually hijacking the heat sensors in your mouth to trick your body into thinking \"Wow, this is very hot\". As result our bodies start sweating (to cool us off) and we get a runny nose (to protect our nasal tract from damage).",
"Capsaicinoids bind to the TRPV1 receptor in mammals to simulate the body's response to overheating, resulting in sweating and other cooling attempts. However because birds don't have the TRPV1 protein they are generally immune from the effects of capsaicin. URL_0"
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n7zu3p | How come that professional cameras rarely have above 40 Megapixels but some phones have 50 or even 100 Megapixels? | Technology | explainlikeimfive | {
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"Megapixels say little about camera quality. The value of a full size professional camera is in the huge sensor and the large, very complex interchangeable optics. A phone camera physically can't be as good because the laws of physics regarding optics require set sizes and lengths in the optical path to produce a good image. In fact, the higher the megapixels, the worse the camera is - increasing pixel density makes each pixel noisier and worsens low light performance. Those 40-100 megapixel cameras are there because of the marketing departments dickwaving with large numbers. The iPhone and other fancy phones use machine learning and other software tricks to automatically fix up the image afterwards.",
"Megapixels was a major thing in the 2000's and worked as a selling buzz word and nowadays a lot of the buzz is around sensor size and mirror less operation but like the other poster said, it's not all about the pixels. Lens quality and the range and ability from interchangeable SLR and other modular systems combined with quality pieces of glass and the general know how of photography like exposure and composition is what makes the difference. Not many cellphone cameras let you operate in full manual or use high end lenses. Edit: sorry, grammar on a phone keyboard can be horrible.",
"Because they trade off pixel count for pixel (each individual, physical sensor) size. Phone camera sensors are about 25 mm^2, while (the \"standard\") camera sensor is 36mm by 24mm. Pixel size matters when it comes to capturing more light (which full sized cameras take full advantage of), meaning you can get away with using settings which would make a phone's camera unable to take usable pictures. Aside from that, \"professional\" cameras work with raw format, which have very little compression for more flexibility while editing, if needed. Because they have little compression, they're huge in size (my 6D's 24MP raw images weight 24 Mb, while Sony's A7's 40MP raw images weight around 100 Mb).",
"Megapixels is a measure of 1 million pixels on the sensor, 40 megapixels is 40 million pixels. Now that's just how many pixels the camera sensor can see, how much you want to save is largely independent of that, for your average Joe, you don't really want to save more than ~8 million pixels (4K images are 8294400 pixels exactly), so the camera will just average the pixels out. For a studio environment they will use those 40 million pixels exactly as the sensor sees them."
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n80ogl | how could a laser pulse have as much energy as all of the sunlight that reaches earth? | Physics | explainlikeimfive | {
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"So the article is playing a bit of a numbers game, it's not equivalent to the sun's energy that hits the earth. Firstly the laser isn't continuously on. It only runs for an incredibly short pulse of time. The total energy delivered in the pulse is about 300 joules. For reference, a phone battery contains about 50000 joules of energy. So it's not actually a lot of energy. The clever bit is that energy is delivered as a pulse that's only 20 femtoseconds long. So that whole 300 joules is released in only 0.00000000000002 seconds. This gives a crazy power output, but it's only for an incredibly short period of time. After that the capacitors which store the energy for the laser to run need quite a long time to recharge again. The second thing is that it doesn't actually match the power of the sun for 20 femtoseconds, its about 100 times less. Its the same beam intensity as focusing the sun's solar power that hits the earth down to an area that's 10 microns across. The actual beam from the laser is only 1 micron across - so 100 times smaller area, so to reach the same intensity requires only 1/100th of the power. So what it's really saying is if you took 1/100th of the power from the sun that hits the earth; the laser could match that amount of power for 0.00000000000002 seconds. Edit: This is still a phenomenal feat!",
"So, first things first. Let's talk about the difference between *energy* and *power.* Think of a bucket of water. The size of a bucket would be the energy, and how quickly you fill up or empty that bucket. For if I take a five-gallon bucket but flip it over you could say \"that's using water faster than 10 average American homes!\" I mean...yeah for that half-second the water is falling out of that bucket sure. But in the end, I only poured out five gallons of water. & #x200B; Now on to these lasers, what's happening is that we are filling a very very small bucket very very very quickly. From what I have found that laser is on for one femtosecond and covers an area of 1 square micron? So how much *energy* is that? Well, here's some quick napkin math, thats 10^(23) watts per cm over 20 femtoseconds. In an area that's only 1 square micron. so We multiple 10^(23) \\*10^(-8) \\*10^(-15 \\*)20 20 joules of energy in that laser. How much is 20 joules of energy? About what your average LED light bulb uses in 2 seconds. That sounds a lot less impressive though. That said this feat is still pretty amazing, moving energy around that quickly is crazy. But it's not as physics-breaking as the media wants to make it sound."
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n81xx8 | Why is it bad for normal people to take ADHD medication like Adderall to focus better? | As I get older I find my ability to focus is worse than when I was young. I don't have ADHD, but... it seems like I could take the same medications. Why is that bad? | Biology | explainlikeimfive | {
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"Its highly addictive, it has bad side effects if you abuse it and if you don't need it, it really messes up your brain chemistry.",
"Making this a top line comment: My understanding is this: People with ADHD don’t have enough dopamine. People without ADHD do have enough dopamine. Adderall increases dopamine. Therefore, people with ADHD who use Adderall get their dopamine level increased so that they finally have enough. People without ADHD who use Adderall get their dopamine level increased so that they have too much. Too much of anything in your brain or body is usually bad, but according to some googling I did, too much dopamine can lead to anxiety, mania, and delusions."
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n81z64 | How does “the house” have the edge in blackjack? | Ya know how they say with all casino games the house is the favourite? How does this apply to blackjack? | Other | explainlikeimfive | {
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"By forcing you to expose your cards 1st, and run the risk of going over 21 before the dealer does, gives the house the advantage.",
"You have to play your hand first. You can bust and lose before the dealer or house does a single thing. This is compounded if you make mistakes from poor strategy or being unable to see one of his cards. The house can further favor itself with rule changes like paying out five-card charlie or non-3:2 blackjack payouts.",
"If both players bust out (go over 21), the house wins because you go first and they took your money before they went over as well. The blackjack \"insurance\" offer (dealer is showing an Ace) is, mathematically speaking, a bad investment. That said, blackjack is a game where card counting can give you the upper hand against the casino, which is why you can get kicked out for doing it.",
"In blackjack when you play the house and the player draw a card. So there are four situations that can happen here: 1. Player busts, house busts, 2. Player busts, house does not 3. Player does not bust, house busts 4. player does not bust, house does not. The way blackjack works, the player loses money in the first two scenarios and only gets money on the third. That's because the players reveal their cards first, and if they bust the house just wins regardless of if their card would have made them lose. There is obviously more to blackjack, but that's the biggest reason it's in the houses favor"
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n82bb9 | What causes De Ja Vu? | EDIT: thanks for the replies, the theory makes sense to me. But it also reminds me of how little we know about the brain! | Biology | explainlikeimfive | {
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"Okay so I don't remember specifics here, but I know the gist I think. Deja-vu is a phenomenon where somehow the sensory processing in your brain is delayed by like a nanosecond. When you see or hear something, it goes to multiple parts of your brain to be processed. Deja vu happens when that processing is a bit out of sync. Imagine you're a news presenter, and you read some breaking news from the autocue. Then someone in your earpiece tells you there's been some breaking news and you need to read it from the autocue. And you think... I know, I've already read it. That's basically what is happening in your brain - part of it temporarily lags. It causes you to feel that you've already seen something that you're seeing now for the first time. Some parts of your brain processed it faster than your sensory input could.",
"I’m confused, because I was still under the impression it was caused by a glitch in the Matrix.",
"Nurse here. Every input your brain takes in is processed by your hippocampus in the brain. Everything goes into short term memory first and then long term if necessary. Like what did you have for breakfast 9 days ago? Unless you eat the same thing everyday or had something special, you probably can’t remember since your brain decided not to put it in long term memory. When your hippocampus takes something straight into long term memory, your brain recognizes it as something you have seen or already know, causing deja vu. Long story short, it is a malfunction of your hippocampus."
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n82x2s | what makes us itchy? | And also, why is it difficult to ignore? | Biology | explainlikeimfive | {
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"Itchiness is your pain receptors firing but just a *^(tiiiiiny)* bit. Often this is from a chemical called histamine which your immune cells release in response to what they see as an invasion. Histamine triggers pain receptors (again a ^(tiny) bit), causes vessels to dilate, and if there are wet/mucusy things nearby influences them to make them wetter/more mucusy (like your nose/eyes). Its purpose is to signal to you that something irritating is on your skin and you should get it off. The body is amazing, but can be pretty dumb sometimes, too. Even after the irritant is gone, the histamine sticks around. And if you have seasonal allergies, or are specifically allergic to something like peanuts, crawfish, meds, or whatever then your immune system is like a doomsday prepper just waiting to break out the big guns like it's the apocalypse at the slightest insult."
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n83l3w | How does the Monte Carlo method work, and apart from Pi, what can it be used to approximate? | Mathematics | explainlikeimfive | {
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"Monte Carlo method basically just means: \"simulate something a lot of times.\" For example, let's say you want to know the odds of getting exactly three heads out of 10 coin flips (in any order). Yes, you can calculate this mathematically but let's say you don't want to. Instead, you write a computer program that does 10 coin flips. But also it does this set of 10 coin flips ten million times. Each time a set of 10 flips results in exactly three heads, you note it and count, out of those ten million times, that event happened. This also gives you the odds. The Monte Carlo method can be used to empirically come up with a mathematical result by doing something so many times that variations and flukes due to randomness cancel each other out.",
"So I am actually running a monte carlo simulation for a research project right now, here is the reason I would argue its the right tool for certain jobs. (hopefully in layman's terms) In research, we like to have testable hypothesis, so that we can give some estimate of whether our results are simply due to random chance, or whether we truly have a real result. The simplest way to do this is by running a linear regression. Without getting into what that actually entails, it is sinple enough to say that linear regression relies on a few assumptions. One of those assumptions is that we know what the distribution of our outcome is. For example, we know that a truely random coin should have a 50% chance of heads and a 50% chance of tails. Because we know this information, we can exactly determine how likely it was that we saw \"H H H H\" on 4 flips. We can then use that information to make the statement, The chance of getting 4 Hs in a row was ~6.25%. However, when we do not exactly know the distribution, we have to make assumptions about it, and those assumptions can have large impacts on our estimates of how likely an event was. For example, what if we though the chance to get a heads on a fair coin was 60%? Then we would assume that we would get 4 Hs in a row almost 13% of the time, which as you can see greatly changes our estimate of how likely the event we observed was How does a monte carlo simulation help? By using a monte carlo, we dont make any assumptions about the distribution, instead we let the data tell us what the distribution is and make our inferences on the liklihood based on the simulation."
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n83z3a | how did plate tectonics first start? | Earth Science | explainlikeimfive | {
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"As the surface of the Earth cooled, a thin crust solidified. Underneath, there were currents in the liquidish rock which pulled the crust with them, like rafts of ice on a pond as it's just freezing.",
"not sure if this answers your question. the magma inside the earth moves around causing the tectonic plates above move around."
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n843qu | How do underwater volcanoes work... | Like wouldn’t the lava cool off or something? I understand they happen but I can’t make my brain GET IT. My 7 year old is asking ALL the volcano questions and I feel dumb. Thanks! | Earth Science | explainlikeimfive | {
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"You have to remember that lava isn't fire. It isn't extinguished by water. It's literally molten rock at thousands of degrees. Yes, water will cool it down, but so does air. Water just does it a little faster. [Take a look at this video of a small underwater lava flow]( URL_0 ). You can see that the lava cools and solidifies pretty quickly but then the hot lava behind it breaks through and flows until it cools and solidifies, and then then more lava behind \\*that\\* breaks through and it keeps going like that. The lava has to go somewhere and the thin shell cooled down by the water is no match for the lava behind it.",
"From what I know, cause I wanna give you a fast answer, they do cool off and form into rocks but the magma that is still produced underneath will break through those rocks as they are very very hot. The result is fissures or water vapor clouds."
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n84k5t | why does time slow down the farther you get from the sun? | Other | explainlikeimfive | {
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"Time is affected by gravity and acceleration, not proximity to the sun. This is the basis of time dialation. But what i assume you mean is why are years longers the farther from the sun you are, and thats because the planets farther out have to travel a much longer distance to finish one full rotation.",
"Wouldn’t it speed up? As time slows as gravity increases? Or am i very wrong"
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n84o18 | With all the rather drastic effects to a woman's body during pregnancy, how do some women give birth not knowing they were pregnant? | This question occurred to me after seeing [this]( URL_0 ) article. | Biology | explainlikeimfive | {
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"Not everyone menstruates regularly. Not everyone gains a lot of weight during pregnancy. Also, with obesity being common, some women don't look \"stereotypically pregnant\". Sometimes, fetal movement feels like gas bubbles. Contractions can feel like cramping, if you don't realize what they are.",
"Usually, as a foetus grows, it becomes very visible. Sometimes - very occasionally - that is not the case. Either a woman is overweight and the pregnancy is not visible because of that, or the baby simply does protrude. It seems impossible, but it does happen. These women can look entirely not-pregnant the week before giving birth. It’s a bizarre and very rare condition. The women that this happens to also tend to have sporadic periods, or else their periods continue through their pregnancy - something that can happen during any pregnancy. It’s not a real period, it’s something called spotting. But if you don’t know you’re pregnant, and are used to light periods, how would you know the difference?"
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n858lz | How does fruit get to grow to full size without being eaten by animals right away? | Edit: For clarity, this isn't a question about why plants grow fruits and why animals eat them. It's about what allows the fruit to grow big enough to develop seeds before being eaten as soon as they bud anything nutritious. | Biology | explainlikeimfive | {
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"It happens all the time man. Thats part of why plants have so many buds. Plus, thats why a lot of plants have fruits in the first place, to be eaten. Animal eats the fruit, animal poops out the fruit seeds with some nice fertilizer. We just took those fruits and bred them to be enormous for our consumption.",
"A bank is opening at 8 a.m. When it opens it's going to give away $1,000 to the first 1,000 people that walk through the door. Specializing to eat unripe fruits is like robbing that bank at 7 a.m and immediately running as soon as you get a single $20 bill from the teller. It is a way to get money, but it requires you to overcome a lot of defenses for a very minor gain. Fruiting trees have an additional layer I couldn't figure out how to torture into my metaphor, because the unripe fruits are just about as transitory as the ripe ones. They only occur at specific times. It would require specializations to help a creature eat low-value, well defended *and* scarce food. That's gonna be rare. Much easier traits to luck into would be things that could help you out compete your neighbors and get yourself through the door on free money day. Which is what we see out of successful wild fruiting trees."
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n85t6m | This math riddle | Mathematics | explainlikeimfive | {
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"The 27 dollars includes the money they paid ($25) and the $2 the waitress takes. The remaining three dollars are the $1 given to each customer. (for a total of 30, 27 + 3) The riddle phrases things in an illogical manner to sound confusing.",
"The error is in the very last step. Instead of adding $2 to $27 to get $29, you should be *subtracting* $2 to get the true cost of the meal paid to the restaurant, $25.",
"The problem is in the fact that you're trying to add up the remaining value of each step of the original process, which is related to but does not directly affect what the actual original amounts were. Like, if I had $1,000 and you took out $250 three times, you'd have a remainder of $750, $500, and then $250. If you add $250 to $500 you have $750, plus the other $750 gives you $1500, which is $500 more than the original $1,000! In this case, they *did* pay $10, which equals $30. The waitress gave back $3 and pocketed $2, which equals $5 (the difference between $30 and $25). The other explanation about 9 x 3 is just a distraction, because they ... paid more than 9 at the end of the day.",
"The mistake is in adding the 2 dollars from the waitress. Look at it the other way around, 3 friends have to pay 25 dollars in total, so they each give 9 dollars, the 2 extra ones are a tip for the waitress. If you want to get back to the original 30 dollars in your version, you have to keep in mind that the 2 dollars that the waitress has came from the money they paid so it can't be added on top, and the 3 missing dollars from the 27 stack are the ones the waitress gave them back"
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n86lcc | How did the scientists track the falling orbit of Long March 5B in real time, and make predicition about the possible landing spots? | Technology | explainlikeimfive | {
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"Radar. Radar tracking can tell us the position, altitude, and velocity of any object. Over the last few days, various governments were tracking it with radar and noting how its orbit was degrading. We can do a reasonably good job of modeling orbital decay so we could say \"its altitude is dropping by X amount each orbit, by this orbit it'll be so low that it'll just burn up\". Of course there are always variables so we couldn't pinpoint the exact spot until after it happened."
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n86o0b | Why is it such a big deal if the source code for a program/website is leaked? What's the worst someone could do with it? | Technology | explainlikeimfive | {
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"The source code is like the recipe for that software. It literally is what the program does and how it works. There are two reasons source code leaks are bad: 1. A competitor can get it, figure out how the key bits work, and add them to their own software. This negates whatever competitive advantage the original company has. 2. A malicious actor can find bugs and write exploits for them. Potentially opening up whoever uses the software to cyber attacks.",
"Someone could work out if there is a potential flaw in it and use it hack the system. What could they get? Well depends what's stored? CC numbers? People's passwords? People emails, addresses? Maybe other stuff. Or they could just sell the flaw to criminals who could do it. Identify theft is a thing. And next what about the trust the company has lost? Who would trust them with info? This is the kind of thing that could destroy a business and potentially the lives of many people."
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n86phm | why does water taste better or worse depending on its temperature | Chemistry | explainlikeimfive | {
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"Personal preference, really. Some people like ice cold water, some like cool water without ice. I prefer room temperature water. I also like hot water with lemon. If you are experiencing heat exhaustion, dont drink ice cold water because you could shock your system. Ambient temperature is good.",
"Warm water has a higher threshold for dissolving non-water molecules, so warm tap water usually contains more ionic metals from the pipes and general dirt and grime which alters the taste. It is also likely an adaptive response, since water closer to our body temperature (37.5 C) is more likely to contain a germ that can make us sick.",
"My guess is it is somewhat evolutionary. Cold crisp river water is less likely to have things in it that would make you sick than a still pool of air temp water. Also, I don’t think we taste cold things as much so even if it was the exact same water we would prefer it colder because water that has a flavor to it means it’s contaminated with something."
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n86xhk | why the housing market is so crazy right now. Why is it such an insane seller's market? | Other | explainlikeimfive | {
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"Interest rates on home loans hit an all-time low in January/February, making it cheap to borrow. But COVID has also caused a shift from urban markets to suburban/rural ones, as employers started allowing more work-from-home (making it easier for people to move to areas with a lower cost of living/lower taxes). People also realized there's a health risk living in high density cities. In NYC, for example, the housing market crashed as housing inventory increased and fewer buyers were interested in moving there; in the surrounding areas, the housing market surged, for the opposite reasons."
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n86xl8 | Why are bananas and potatoes still stable around water, despite being full of potassium? | I mean really! Potassium explodes when it gets wet, so why don’t these foods? I assume the answer is something simple like, “Because there isn’t enough of it.” But even that still confuses me, because if it’s simply a chemical reaction, why would there be some sort of criteria on how much potassium it takes? | Chemistry | explainlikeimfive | {
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"Because there is no metallic potassium in them. Metallic potassium is highly reactive when it comes in contact with water. But it's all bound up in different molecules that it's already reacted with so it doesn't react with water, or doesn't react nearly as enthusiastically.",
"Only pure potassium metal is explosive with water. The potassium you're finding in foods are potassium ions K+ e.g. potassium chloride K+Cl-, potassium iodide, potassium carbonate, etc etc. You don't find pure potassium metal in nature, it's too reactive."
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n876ba | Why can’t people just code in more digital money whenever they want to? | Whether it be something fully digital like Bitcoin, or just the digitized money contained in a credit card or similar, why can’t someone just go in and code more money whenever they feel like it, seeing as how it’s just a string of 1’s and 0’s like everything else? And if it’s a security thing, why couldn’t the owner of the bank’s data, or the digital money system just code it in and give everyone or themselves free money? | Economics | explainlikeimfive | {
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"Bitcoin and those styles of decentralized currency don't have a central database to hack. Every transaction/mining operation is verified by the entire network (everyone who is mining), so you'd need a majority of those people to be in on the scam in order to pull it off. If you report a different transaction than everyone else, your transaction gets discarded as \"incorrect\". Centralized systems like banks use double-entry bookkeeping. That means that, for every addition to an account, there must either be a subtraction from another account (transferring funds) or a physical input (cashing a check or depositing cash). So the system admin would have to either fake transactions from real accounts (in which the owners would quickly find out) or try to fake a physical interaction (counterfeit money or a fraudulent check) in order to gain money for themselves. It should be self-evident that, if you're making counterfeit money that can pass bank inspections, you're in a far different tier than hacking bank accounts. And the banks' digital security is generally very good. Most fraud cases are from the physical or human elements (stealing cards, tricking people into handing over bank information, etc.) rather than hacking the system."
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n88u1i | How does a CPU do math? | Let’s say I run a JavaScript file that executes some basic math, how does the processor actually determine the result of the arithmetic? | Other | explainlikeimfive | {
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"If you're REALLY interested, [ URL_0 ]( URL_0 ) takes you through the process of building a working computer (including math operations) from individual logic gates (specifically, only using NAND gates, which are universal)"
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n890sr | Why can we use math to shoot a rocket and pinpoint another planet, but we can't figure out where that space junk will land tomorrow? | I get that it might break up, which makes the physics trickier... but can't they calculate something like "it will land on San Diego if it stays in 1 piece but if it breaks up it will land in Canada"? | Mathematics | explainlikeimfive | {
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"When we intentionally land a probe on another planet it's guided. We know exactly where it is, its orientation, and it can steer itself to its intended target. A piece of space junk isn't guided and is subject to variables that we can't control and don't know such as its orientation as it tumbles and the exact atmospheric conditions as it reenters.",
"It is easy to calculate things we know everything about. What we can't calculate is things we don't know. \"It breaks up\" isn't a single thing. Which pieces fall off, how large are they, when precisely do they break, what angles do they form, at what point in the atmosphere do they do this, etc.? All those can have huge impacts on the outcome, and there is really no way for people trying to do calculations to know them. Which of the bolts or welds in the craft will fail first? Imagine trying to throw a handful of confetti into the air off a 20 story building and calculate where each piece will hit the ground before it happens, can you do that?",
"It's not controlled, and it's moving so fast that one tiny variable could throw it off by like 18,000 miles. And there are a lot of variables.",
"My personal research subject gets involved: To steer a rocket you need feedback control. You need to constantly measure the exact state (velocity, angle, air density, mass, ...) to send the correct commands to stabilize it. For junk we don't have sensors to measure it, and no ways to influence it's path. So it will get instable wich basically means the butterfly effect happens and tiny differences in the startpoint have huge consequences in the outcome",
"Chaos. (Short) interplanetary travel is very un-chaotic. If you go a little faster, you'll arrive a little bit to the left, if you go a little slower, you'll arrive at a location a little bit more to the right. A change in the input (your speed) has a very predictable and proportional consequence for the output (the landing point). Everything involving atmosphere however is extremely chaotic, meaning a small change in the input causes a completely different outcome. For example, being a little bit slower could mean arriving a bit later at a location, when there is high-pressure weather, therefore slowing you down more. If you were just a little faster, you could have avoided that and end up with a completely different speed afterwards. And yes, there's weather in the upper atmosphere. It fluctuates wildly in density."
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n89396 | Why does fire (specifically a candle flame) make noise when you blow on it? | Chemistry | explainlikeimfive | {
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"Fire consumes oxygen. A candle is normally fairly stable. Blowing on it disrupts that. It causes the air to vibrate slightly. Sound is created when something vibrates and sends waves of energy (vibration) into our ears. The vibrations travel through the air to the ear"
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n89jzb | What is alcohol actually doing when it makes you do things you wouldn't normally do sober? | In store I work in after pubs shut. 20 something climbed inside shopping trolley and was pushed along carpark. The trolley tipped and the passenger became unconscious after banging head. If the passenger was sober they most likely would have decided against this so what is alcohol actually doing when drunk that gives false courage? | Biology | explainlikeimfive | {
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"Alcohol is mainly an inhibitor, so it stops things from working. The first ones you notice are your motor skills, pain receptors and balance going bad. The false courage thing comes from the alcohol stopping your decision center. That one basically takes everything you would like to do and then decides if you actually should do it or not. When it is disabled you get random ideas and don't evaluate if you should actually do them, you just do. Together with your impaired motor skills and higher pain threshold, this is a recipe for disaster. and that is why people hurt themselves when drunk.",
"Your prefrontal cortex has an important role for your brain's executive functioning, including the capacity to make judgements and adhere to normal inhibitions. When you drink alcohol the blood flow in this region is abnormal, and certain receptors seem to not work as well. So your brain won't tell you not to do what you normally wouldn't do. This is why it's super important not to trust your future self's judgement on, say, not driving home drunk. It's better to not give yourself any risky options."
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n89u4z | When we eat too much, why do we get tired? Shouldn't we instead get a lot of energy from the food? | Biology | explainlikeimfive | {
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"Digestion takes a lot of energy. Your body likes to digest things as soon as possible to make more fuel for further shenanigans. You digest things much more efficiently when your body doesn't have to do anything else. Therefore...Sleep is a viable option after eating a large meal that needs time to digest.",
"It's because your body is sending all it's blood/energy to breaking down the food. The calories aren't instantaneous.",
"The blood goes to your stomach to aid digestion, making you tired for a bit, but then after 20 or so minutes your bloody returns to circulate properly and you benefit from the new energy received from the food. In Spanish they call this period a sobre mesa, where they wait 20 minutes after a meal for the energy to kick in before leaving the table",
"it depends on the food you eat. You can eat a ton of veggies and not get tired. Someone said meat and potatoes and that was correct (carbs and protein). But the real culprit is over eating. Eat enough to live and you will see a difference versus living to eat. why do people feel tired after eating]( URL_0 )"
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n8a5u2 | what can you do with an IP address? | Hi, so what can someone do with your IP address? So if someone managed to get ahold of my IP, can they find out where I live, and essentially my identity? Just wondering because I’m wondering how streamers get swatted. I’m not going to swat anyone obviously but I thought IP address only show a geographical location, can hackers really find out where you live and your identity? Or is an IP address useless? What can an ordinary person or hacker do if they got ahold of your IP? | Technology | explainlikeimfive | {
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"> So if someone managed to get ahold of my IP, can they find out where I live, and essentially my identity? At first they can find out roughly where you live. So like your next bigger city, nothing else. If they want more they need the information your ISP has, and they will only give it out to the police when they have a warrant. So if you're not doing anything illegal you shouldn't worry about people seeing your IP. In fact every website you visit has it.",
"As others have said, it really depends. IP addresses identify your ISP; your ISP is likely able to map an IP address (and the time it was used) to a given customer. So law enforcement, or someone who works at your ISP, can probably determine your real-world identity from your IP address. A random person on the internet is far less likely to be able to do that; what they are likely to be able to do is identify your rough geographic area, through a variety of techniques. (The network layout of many ISPs--the IP address, but also the route to get to that IP address--often gives away some rough geographic data, at the city level; a number of services also exist that aim to do better (more accurate, finer grained) IP geolocation from other data sources.) However, again, it depends on what kind of access someone has. I'm dating myself here, but an oldie but goodie is Samy Kamkar's talk from Defcon 18 (which apparently was back in 2010, so apparently I'm old now?): [ URL_0 ]( URL_0 ). Some of this is no longer current, but it gives you a sense of what might be possible."
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n8aazd | How can Digital data be stored on Magnetic tape? | Technology | explainlikeimfive | {
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"to simplify: magnetic tape is a piece of plastic with some iron on the surface. Iron can be magnetized if exposed to a strong enough magnetic field. A magnet has two poles, north and south. The easiest way to save digital data on a tape is to expose each section of the tape to either the south pole of a magnet or the north pole and magnetize it. The write head has a strong electromagnet that is used to generate the required magnetic field. Since digital data is a series of 0 e 1, each bit can be encoded as the orientation (north or south) of the magnetization of the tape. The read head has a sensor that detects the magnetization without altering it. Modern devices are more complex than that but the principle is the same.",
"Just as one can encode analog data (sound, images) on digital signals, the opposite is also possible: encoding digital data on analog signals. Magnetic tape just stores the digital information in the patterns of magnetism on a magnetic tape. This is exactly like how data is stored on a hard disk drive, but instead of a spinning metal platter, the magnetic pattern is stored on a plastic tape."
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n8atb3 | why do plants w/o fruit blossom/ get pollinated? | It doesn‘t make sense to me, why do plants like roses and tulips for example have blossoms when they don‘t bare any fruit from it to reproduce? | Biology | explainlikeimfive | {
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"Roses and tulips *do* produce fruit. Rose hips are the seed pods of roses. If the tulip flowers aren't harvested the flower ripens into a pod (similar to a poppy pod) & seeds form. It's just easier to grow annual flowers from bulbs.",
"Most fruiting trees use the fruit that you and I eat as nutrients for the seeds inside. The fruit that we enjoy is designed to be eaten/dropped and then used to fertilize a new plant. Flowers are no different other than they rely on bees and other pollinators who rely on them for food to spread their seed. Pollen is basically plant sperm. Flowering plants that don't produce fruit rely on pollinators such as Bees to spread their \"seeds\". Symbiotic relationships exist throughout the animal kingdom."
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n8baeb | why "no excercise = tiredness" but "excercising = energy" | Biology | explainlikeimfive | {
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"Simply put, the more active you are the more mitochondria your body produces. It's like a domino effect. The more you exercise, the body makes more mitochondria to make more energy. Just reply if you need a more in-depth answer.",
"This has to do the with arousal systems in your brain. Exercise releases cortisol and adrenaline and activates the sympathetic nervous system (increased heart rate, increased alertness and arousal) and activates the reticular activating system. That makes you feel more awake . Also release growth hormone and other endocrine things. Among other things which have nothing to do with load or mitochondria. Or stacking. Or supercompensation (all of these ar bro science and not actual science). Think of it this way. Humans (not all animals but humans in particular) have a really use it or lose it policy. If you dont need to pay attention, because ain’t nothing happening, then conserve the energy and be quiet and don’t move. Another way to think about it is that up until the last couple hundred years you would have been having to move around at least a little bit to do anything at all -even the easiest of cooking would have required poking a fire, stirring while separating your warring children , and peeling off inedible parts from edible parts of plants. So not weightlifting but you would have been walking and moving almost conststantly. Untill it was time to go to sleep. When the long time of inactivity signals the depression of the reticular activating system so that you can do that. It is only with the advent of very modern living that you would have ever really been able to be totally still except your thumbs while scrolling for any really long time.",
"Your body adapts to the demand you put on it. If you do exercise then you \"level up\" and basic tasks like walking around or just staying active/awake become easier too."
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n8bid0 | how do we measure the height of mountains? | Earth Science | explainlikeimfive | {
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"One way is geometry. Stand in a spot and measure the angle to the top. Now you know two angles and a side of a right triangle (the angle to the top from where you're standing, the default 90 degree angle of a right triangle, and the length of the side that is the distance from you to the mountain). Then you can calculate the height of the triangle which is the height of the mountain. Keep in mind this only gives you the height to the top relative to where you're standing, so if you want the height of the mountain relative to sea level you have to know how high above sea level you're measuring from.",
"The modern way? Attach a GPS device to the top of the mountain. It tells you exactly how high above sea level it and you can check it remotely. You can also use strong lasers to measure some angles and use geometry to create triangles with known distances. This is slightly less accurate than GPS, but still very accurate. The original survey of Everest was done with standard surveying tools of the time, namely a sextant. It's more-or-less the same idea as using lasers to measure angles and then building triangles with geometry to figure out the math. Slightly less accurate than lasers, but still pretty good. They nailed the height of Everest down to the foot that way.",
"The first guy (George Everest) to measure everest spent years sighting and using trig to work out the height, and came up with exactly 29000 feet. Thinking that people would just think that he guessed he added a bit so make it sound more accurate - and reported that the height was exactly 29002 feet. He was the first person to put 2 feet on everest... (thank you QI)",
"The way you are describing of manually measure the distance using measuring sticks and plumb lines and such is possible for smaller elevations near the coast but does indeed have its limits when it comes to huge inland mountains. However what we can do is to use a telescope and measure angles between different points. So if you stand on two points and you know their exact coordinates and elevation and measure the angles from these points to say mount Everest then you are able to do some basic trigonometry to calculate its exact elevation. And the problem of knowing the elevations of the points you measure from can be solved in a very similar way using other points. Eventually the elevations you are measuring becomes so small that you can do it using simpler methods.",
"By measuring air pressure on ground and on the mountain. Let's say you're on the sea level. You have around 11km of air above you and all that air is putting a pressure on everything around you. We can measure the pressure. Then we can measure the pressure on the mountain, where there's 11km-H amount of air above you where H is the height of the mountain. Here the pressure is lower because there is less air above you pushing down on you. The difference of the pressure the air makes is proportional to the difference in height of the air above you in these 2 locations. If you have any additional questions, feel free to ask here or in DMs. This is how aeroplanes measure their altitude and I believe it's also used for other applications."
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n8cclq | Why do you get chills when you have a temperature? | Biology | explainlikeimfive | {
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"Because you are experiencing the difference in internal body temp vs skin temp vs Air temp. As your internal temp rises, you become hyper aware of the cooler skin and air temp, tricking your brain into panicking that your in a cold environment and must do something to prevent becoming hypothermic."
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n8dq5y | how does soap make bubbles? | Doing the dishes, I added soap to the water, swish my hand around and magically bubbles just form. How? | Chemistry | explainlikeimfive | {
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"Soap molecules have a side that wants to be in contact in water (hydrophilic), and a side that does not (hydrophobic). If you put a bunch of them in water, they'll naturally clump together with the hydrophilic sides facing out and the hydrophobic sides facing in. They can also organize into a longer, straight membrane (a double layer of soap molecules with hydrophobic sides together and hydrophilic sides pointing out), and that's when you get bubbles. On a side note, the lipid bilayer membranes of living cells are made in a very similar way."
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n8e740 | what is the concept of comfort zone? | Biology | explainlikeimfive | {
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"There are things you are comfortable with and things you are not. When you are in your comfort zone you are generally not being challenged and can just kind of “exist”. When you push out of your comfort zone by doing something uncomfortable you are (hopefully) developing new skills to broaden you comfort zone. It’s a very fluid concept that has to do with motivation and desensitization"
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n8e82q | Why does cranberry juice make your mouth feel tight after drinking it? | Biology | explainlikeimfive | {
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"What I understand from a quick Google session: Cranberry juice contains lots of tannins. When tannins interact with the proteins in your saliva, these proteins clump together. This clumping makes your mouth feel very dry. This is the sensation you experience (also known as astringency. URL_0 ."
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n8eefy | what is the biological reason for sexual arousal in women before their menstruation? | Biology | explainlikeimfive | {
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"text": [
"Before a woman has her period she’s going through something called ovulation which is several days of heightened arousal where she is most likely to get pregnant. The menstrual cycle is, briefly, a repeating pattern in a woman’s ovaries and uterus preparing for pregnancy. For a couple weeks she has an egg in her ovaries that is selected to mature and develop while her uterus begins growing an inner lining that is the ideal home for a fertilized egg to implant in and grow. When conditions begin to become ideal for pregnancy, she ovulates: the egg is released from the ovary and into the tubes which carry it to the uterus. Hormones fluctuate throughout the entirety of the cycle, but this is where the arousal will be highest. If the egg is fertilized with sperm and implanted into the uterus, she is now pregnant. Otherwise vessels which supply that lining that was created cinch themselves off and the lining breaks away. This is menstruation, and the lining/egg slough off. It takes 3-7 days generally for this process to complete and reset. I understand this goes into further detail than you were asking, but a basic understanding of the cycle helps with understanding of things related to it. Edit: For clarification, [the rough timeline]( URL_0 ) is Day 0 - beginning of menses, Day 14 - ovulation and increased arousal, roughly Day 23-27 arousal tapers off, Day 27-30 risk for pre-menstrual mood swings/pain/cramps, then Day 0 again with menses. Everyone's a little bit different, though, and this is the average. Your experience may vary.",
"I don't think that's what the OP means. I could be totally off base, but I saw the question as why do (some) women get very aroused or \"horny\" JUST before their period week. I've had some past partners who would get very horny a couple of days before, and during their periods, but all were on the pill for birth control. From what I've gathered over time, and by no means am an 'expert', but the pill for contraception messes with a woman's natural hormones to work, and that sometimes stymies their sex drive. When they stop taking the pill for the period week, the sex drive comes back in a rush. If that's OP was talking about anyways. I always thought ovulation occurred roughly 1.5-2 weeks before the \"menstrual reset\" week",
"Why does it sound like all the people answering this are men/people who have never menstruated? OP is asking why many people have an increase in libido in the days leading up to menstruation. It has no biological benefit (you’re very likely not going to fertilize an egg on days 25-29), so why the increased sex drive? As a women who menstruates I can attest that this happens to me."
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n8egxv | Why do people get a bad taste in their mouth after a short nap but rarely after sleeping the entire night? | Chemistry | explainlikeimfive | {
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"Do people not wake up with gross morning breath? I thought that was a pretty common well known thing. You don't brush your teeth before a nap generally, so that's likely what would do it of for you.",
"I want to know why my wife and I can take a nap fully clothed and wrapped in each other's arms, but when it's \"bedtime\" that would be way too warm and uncomfortable.",
"Because most people don't brush their teeth before taking a nap; as opposed to doingso before going to bed. The taste comes from the bacteria in your mouth having a feast while you're napping. Hence, your mouth tastes and feels like the bottom of a cockie cage after a nap.",
"Maybe because people brush their teeth before going to bed at night but not before a nap? Still, I do this and wake up in the morning with stank breath anyway."
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n8eqag | How do drugs get to work? | Biology | explainlikeimfive | {
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"text": [
"Well like you said they all act differently so this is going to be a very broad answer. But essentially you can inject a drug directly into your bloodstream, some can be absorbed through skin, some are injested, and some are inhaled. All of these serve the purpose of delivering the drug into the bloodstream. Sometimes there are extra steps to get there, but thats the end goal. Once it's in the bloodstream the compounds are distributed throughout throughout body and reacts with whatever its meant to react with. Maybe that's some chemicals passing the blood/brain barrier to alter a process in the brain. Maybe it's meant to interact with a specific enzyme or trigger a reaction from another organ or system. Super vague, but thats the gist. A delivery mechanism to get it into the bloodstream so it can be distributed throughout the body and produce the desired reaction."
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n8f0gb | Why does drying laundry on a line leave it wrinkly and feeling crispy? | Physics | explainlikeimfive | {
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"text": [
"The crinkle is from both left over soap and minerals drying and hardening. When you use tumble dryer, the same hardening happens, but in lots of small spots. On a Line the entire item can harden as one.",
"Wrinkly, sure but it shouldn't be 'crispy'. You sure you're not using too much soap and it's not all rinsing out? Anyway, in order to remove wrinkles from fabric you use a combination of heat, moisture and pressure to cause the fabric to soften, flatten, and then stay in that shape. Ironing clothes uses two or three of these. Hanging shirts up as soon as they come warm out of the dryer applies heat and moisture, so that works too unless you let them sit in a pile too long and they just get wrinkly again because the heat and residual moisture move away. On a clothesline you don't have any of those things, but you do have a wind's constant manipulation of the fabric to make it kind of bend the wrinkles out by flexing the fabric. This works a little, but not as well as ironing, and fails worse with small objects like a child's thick socks, or when there's no wind involved (like when you're using an indoor drying rack). As it dries in those cases, the fabric isn't really getting manipulated so it relaxes, and so all the folds and creases remain in place."
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n8f8ix | How does your body 'know' to make itself more efficient for carrying out repeated exercises? | For example: after continued weight lifting, how do my muscles know to grow stronger than before, rather than just restoring themselves back to the same size as before? Similarly, how does my body know to increase my VO2 Max after repeated cardio sessions? What tells my body "hey this is going to keep happening, let's make things more efficient 'round here."? Is there some sort of signal or chemical released by the brain, and could we not synthesize this so we'd have a load of buff people walking around? Maybe that's what steroids are, I'm not too sure if I'm honest... Not saying that's necessarily a good idea either, just curious. Thanks in advance! | Biology | explainlikeimfive | {
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"I don't know about Vo2 max, but the gain from weight lifting is kind of incidental; they occur because lifting creates micro-tears, and when these heal up by being stitched together with muscle material, then more muscle mass is overall being created. Of course it's always troublesome to be thinking of autonomic processes as 'conscious' anyway; they are essentially incidental occurrences (like muscle healing) which have proved to be useful and therefore been perpetuated by virtue of evolution, rather than a 'conscious' element of the body *implementing* something deliberate."
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n8fdhj | blackhead or whitehead, how does my nose decide? | Biology | explainlikeimfive | {
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"text": [
"They’re the same basically. A blackhead is just what happens when the pore is open and all the gross oil and skin cells oxidize.",
"There are light and dark whiteheads and then blackheads, which form plugs over the pore and will usually have a reservoir of pus. Whiteheads are unavoidable, but you can reduce the formation of blackheads by washing your face with a gentle cleanser and warm water, and making sure to moisturize if your skin feels \"tight\". Salicylic acid can help reduce the oiliness of your pores, which will address both whiteheads and blackheads. You don't need anything fancy, any drugstore brand (e.g. Clean and Clear) will have a cream or gel that works. If you have sensitive skin, talk to a dermatologist first."
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n8fkxp | Why are emotions like anger, sadness, excitement or boredom so immediately apparent while happiness is not? | If you're angry, sad, or even bored, it's something you can recognize fairly easily. Why isn't happiness as apparent? Rather, why is it so similar to a feeling of "not bad" as opposed to its own unique thing? Is a happy emotion closer to our 'resting state' than most others? | Other | explainlikeimfive | {
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"text": [
"Depends on how you define happiness. If you define happiness as \"not bad\" or just \"relaxed and content\" then it is just a nice comfortable state of being to aim for, it is sustainable and comforting. But that is a state, rather than the emotion itself. The emotion characteristic of happiness is joy, and joy is very noticeable. You'll smile, laugh, maybe even move about when excited with joy. It is very noticeable, it just isnt sustainable.",
"Schopenhauer thought happiness doesn't exist, except as the absence of suffering. We know physical pain has a physical basis with neurochemical response aspect. And it appears to be the case that purely emotional pain is experienced using components similar or identical to those involved in response to physically induced pain. Those are therefore easy to recognize. Yes, it is easy to recognize the euphoric state accompanying the moment of orgasmic sexual release when we experience it, or the tender, cozy satisfaction that accompanies the release of oxytocin while cuddling. But happiness does seem to be the sort of thing we recognize only when looking back with a sense of nostalgia for better times. I think it's because being happy is a experienced as a point at which the boundary that separates inner and outer vanishes, and time experienced as separation of past and future goes poof, and all seems one and now. The objectivity required to observe one's inner state is nowhere to be found; there is a certainty -- possibly illusory -- that all is right with the world, and the small I is one with the great I, and you are happy and productive and free. It's a flow state that passes in the blink of an eye, possibly with a heightened sense of awareness of what is happening at each moment, but without the separation of actor and observer required for judging. The judge is absent.",
"Your question has a general flaw in that your cataloging is a bit off, or perhaps a bit personal. Boredom is a state, not an emotion, and happy people are easy to recognize by their smiles and pitch of voice. But looking at its essence, ***we are hard-wired to want to understand risks, and this is what makes emotions like anger or frustration stand out more than others***. \"That person is angry\" = \"That person could be a threat to me or what I'm trying to do\", and that's important, so we notice it. It's a survival instinct. On the other hand, \"That person is happy\" =/= \"That person could be a threat to me\" (at least not usually). So unless we are actively desiring that person to be happy because we want to make them feel that way, we don't automatically pay as much attention to it."
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n8frhz | Do birds fly for days while over the ocean? How do they sleep? | Biology | explainlikeimfive | {
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"I can actually answer this because of a podcast my 3yo son loves. Two methods: Some birds will fly for weeks at a time non-stop, and they sleep in burst of only a couple seconds, and usually glide while doing so. They do this a few times a minute, so it builds up. Others essentially sleep half their brain at a time, like some whales do. Like, they literally keep flying on autopilot while the left half or right half of the brain sleeps, then they switch sleeping to the other side. Science-wise, we have NFI how animals do either of these things, but that's because we have NFI about the sleep mechanism in general. Edit: NFI = \"No fucking idea\". I wrote this on my phone when I woke up at 2:30am, so got lazy towards the end. Apologies for any confusion. Where I live, I think it's a normal acronym/phrase. My bad. Edit 2: The podcast is \"Imagine This\" which is done by ABC Kids here in Australia. The ABC Kids Listen app has a few really good ones for young kids, from educational to fun to go-the-fuck-to-sleep. The ABC Kids Listen live streaming is geoblocked outside Australai, bit you can still download the app and listen to most podcasts anywhere in the world (according to their FAQ's). Also they have transcripts of almost all their podcasts for the deaf and hard of hearing.",
"Frigates stay aloft for like 60 days without landing. There's other migratory birds that spent like 1 day out of 4 months on land, and the rest of the time they are aloft.",
"A bar-tailed godwit (Limosa lapponica) just flew for 11 days straight from Alaska to New Zealand, traversing a distance of 7,500 miles (12,000 kilometers) without stopping, breaking the longest nonstop flight among birds known to scientists,",
"Some birds have the ability to sleep uni-hemispherically. Meaning one half of their brain goes to sleep while the other half takes the wheel, and vice versa. This is how a lot of fish sleep too so they can keep swimming. In birds that don’t have that ability, I’m fairly sure I saw a David Attenborough documentary where some butterflies did an endurance flight across an ocean. Those who weren’t strong enough drowned, and those who were made it to land. I’m guessing this applies to the birds too? Edit - for those asking for links etc, the book: Why We Sleep by Dr Matthew Walker is one of the most fascinating things I’ve ever read, and my source. Thanks for all the upvotes guys.",
"Swifts can stay in the air for [nearly a] year~~s~~ at a time. To sleep, they find updrafts and fly to great heights, then nap as they slowly fall back to earth. Edited for accuracy.",
"It really depends on the particular bird species and their migration route. But many have the same ability dolphins do, to “partially” sleep allowing them to rest and continue navigating. If the migration route is not over the ocean for several day the species may flip its sleep cycle to take naps during the day. TLDR: species specific Edit: Additional info",
"Scientists have found that migrating birds can fly for 200 days straight, eating and sleeping while soaring through the sky. The species the researchers studied is the Alpine swift, a swallow-like bird found in Europe, Africa, and Asia. Some of the swifts breed in Switzerland, then wing their way across the Sahara to Western Africa for the winters. Based on radar data, scientists “have claimed that some swifts may stay on the wing for almost their whole lifetime except for breeding,” the study authors write in Nature Communications. But, they add, “no data are available at the individual level confirming such long-lasting flights so far.” Long flights aren’t unheard of among birds: Sea birds, for example, may fly for days at a time while searching for food. To find out the swifts’ endurance limits, the team caught six Alpine swifts in Switzerland and tagged them with data loggers. The devices recorded information about light levels (which helped the researchers determine the birds’ locations) and acceleration (which provided information on activity levels). After the birds migrated to Africa and back, the researchers caught three of them and tried to reconstruct the birds’ flight patterns. The team found that the birds tended to flap their wings more at dawn and dusk during the winters. But the most impressive finding was that the swifts appeared to fly nonstop when they weren’t breeding. According to the study, this is the first time that scientists have shown such sustained activity in a non-marine animal. The swifts eat bugs in mid-air, so that explains why they don’t starve. But the results “raise the question of how or whether these birds sleep,” the authors write. The swifts’ activity appeared to rise and fall during flight, and the researchers speculate that the birds might still be able to control their flying while sleeping. The team concludes that “swifts do at least to some extent sleep while airborne.” — Roberta Kwok | 11 October 2013",
"Hope I'm not too late for this one. Sailor here, we've had birds try and land on our ship for rest. But we don't carry food for them, so eventually we'll just have a few bird carcasses we have to push/wash overboard. Or if they try to rest near a radar or communication system to stay away from humans, they just get cooked due to the radiation. Nothing we can really do about it.",
"Great Frigatebirds can stay in the air for up to two months. The Alpine Swift for more than six months. The current-known record belongs to the Common Swift at just over ten months. Studies have shown they sleep in ten to twenty second bursts of sleep while gliding, and in calm weather may even sleep longer, as these swifts have been known to ascend to nearly 10,000 feet and take a lazy circular glide down lasting for quite a while. As for how they sleep, well, studies indicate that a great many bird species are excellent at simply ***not*** sleeping for very long periods of time. For these record-holders, as well as some other long-distance migrants like Arctic Terns, Wandering Albatross, Sooty Shearwater, and even the Barn Swallow, seem to utilize alternating unihemispheric sleep episodes, but just as often take the gliding power-naps I mentioned above.",
"Your question seems to have been answered, but I just wanted to provide my favourite example of trans-oceanic flight: the Blackpoll Warbler! URL_0",
"some birds turn off half their brain while keeping on the other so that they can fly AND sleep!",
"Turkey vultures on the west coast of North America migrate up and down the coast but are terrible fliers (but great gliders). On their way south, they park over southern Vancouver island (city of Victoria) and circle, riding “thermals” higher and higher. Once they are high enough, they glide southwards toward Seattle. Only about 80% make it.",
"I heard they don't! (bird research expert told me) The Bar-tailed godwit migrates from New-Zealand to Korea. It stuffs itself completely and, after barely being able to take of from its huge weight, flies for about 9 days non-stop. Really non-stop. First thing it does when it arrives isn't eating but sleeping because it hasn't slept for 9 days!",
"The thing about the ocean is realizing just how amazingly big it is. I did 6 days on a carrier from Honolulu to San Diego and the only thing we saw was OCEAN. That's at carrier speed, which is a bit higher than most vessels. The fact anything at all can manage to end up somewhere with land is amazing."
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n8ggcs | Why do both coffee (stimulant) and alcohol (depressentt) both make the human body sweat more than usual? | Biology | explainlikeimfive | {
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"Coffee increases heart rate and blood pressure by stimulating the central nervous system, which in turn stimulates sweat glands. Alcohol dilates (widens) blood vessels which makes the extremities/crevices of your body much warmer, which stimulates sweating to cool you off."
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