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m1aszq | why do you gain weight when you are suffering from depression? | Biology | explainlikeimfive | {
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"When you're depressed, you're less likely to want to go out and do things. Additionally, you either eat the same amount or you eat more, because eating is pleasurable and when you're depressed, you want all the pleasure you can get. Less activity and more eating means weight gain."
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m1ayk6 | What does Francis Bacon mean by his 4 idols (tribe, cave, marketplace, theater)? | Other | explainlikeimfive | {
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"The idols of the Tribe is the tendency to treat human perception too highly- humans perceive a distorted view of the world. The idols of the Cave is the specifically individual tendency to treat our own truths as objective truths, forgetting that we're manipulated by our own experiences and biases, just like everything else. The Idol of the Marketplace is the misuse or twisting of words. Specifically, saying things which are technically correct but misrepresentative of reality. Bacon considered this the most dangerous and would have absolutely hated Reddit. The Idols of the Theatre is believing in systems of religion or philosophy that obscure or twist reality. Basically that people tended to look for evidence that supported their worldview, rather than altering their worldview based on new evidence."
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m1bb67 | Critical Thinking; what is it and why is it important. | Other | explainlikeimfive | {
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"Critical thinking is a very broad term that to me, in a nutshell, means learning to doubt your own beliefs. For example, being able to play *devil's advocate* for something that contradicts your worldview - trying to find good counter-arguments against your own arguments - is an important aspect of critical thinking. Another aspect of critical thinking is learning about [cognitive biases]( URL_0 ) and trying to come up with examples of situations in which they're clouding your judgement. The more you practice being able to identify biases, the more you'll automate your awareness of when your own thinking is being affected by one. Edit: I also think it's a common fallacy to equate critical thinking with \"being able to doubt *others*\", which I think is a much less useful skill, and perhaps not coincidentally one that's much easier to seemingly master, especially whenever you read something you don't want to agree with. Don't fall into the trap of patting yourself on the back for being skeptical of something you were already prejudiced against.",
"Say an article says that French people have lower life expectancy than Germans. Without critical thinking, you may just accept that at face value; French people dies sooner. If you were to think critically about it, you would ask questions: is this true? where was this data sourced from? is it possible that the data is incorrect? what is the cause? is the cause misattributed? was the data cherry-picked to give this impression? what other data may be out there to refute, correct, or explain this article?",
"Since many others have already answered the what critical thinking is I'll skip that part. If you do want to learn more, I recommend looking up logic and logical fallacies. These are a great place to start and they really help you to break down an argument into its component parts and then look at each of those parts individually. I'd recommend paying really thinking about anything relating to correlation and causation, as this is one thing people who don't think critically often screw up (at least in my experience). Another common one is Post hoc ergo propter hoc (B followed A, therefore A caused B), I see people use this all the time to justify a home treatment or therapy, especially for young kids. Ex: A parent starts doing a home speech exercise they ready about online and after a while their child's speech improves, therefore the speech exercise worked. Except, we don't know if the child's speech would have improved without the home speech exercise. This is the reason that science uses double blind placebo-controlled studies to conduct research. I took a class in college called Knowledge, Rationality and Understanding that taught me a ton of critical thinking. You may be able to find a similar class if you're in school.",
"It means asking questions to make sure you understand the *\"why?\"* behind a statement, instead of just accepting the statement without any doubts. If someone tells you that it's not safe to go swimming within 30 minutes of eating, ask them what exactly isn't safe about it. Oh! It turns out that it's just something their parents told them, and they don't actually have any idea at all whether or not it's true - they're just repeating what they were told without thinking about it. You look it up and find multiple sources saying that it's actually a myth, and those sources cite the specific evidence behind their claim. The other person wasn't thinking critically; you were."
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m1bbcz | Colour perception is typical described as a material absorbing light wavelengths and reflecting others, with those reflected wavelengths being interpreted as colour. EII5 how are light waves absorbed by a material? Is there a limit to absorption? | Biology | explainlikeimfive | {
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"Materials absorb light by quantum interaction between the photons (light) and the electrons in the material. If the wavelength of light matches up to an electron properly, the electron can absorb the photon and jump up to a higher energy level. Materials have many electrons in many different configurations with many different energy levels so they can absorb a wide range of possible wavelengths. It's not just the interaction of the electron with it's atom, it's also the electron bonds between atoms...that's why different chemical compounds can have different colours even if they involve the same atoms. There's a limit to light absorption in the sense that the energy has to go somewhere, and it's typically going to show up as heat in the material. Eventually you get hot enough to cause the molecules to break down or change state (solid to liquid to gas to plasma)...either will change the electron configuration and energy and the absorption will change.",
"In a very crude sense: Imagine material, as a room of well behaved five years old kids, with kids being the electron, and each of these kids likes a different chocolate. Now suppose that you, a beam of light, carrying a basket full of different chocolates i.e. different wavelengths, enters the room. Now, the kids will take whichever chocolate they like (wavelengths absorbed) and you will come out of the room with fewer chocolates (wavelengths reflected). Now, those kids are having a sugar rush and have gone from well behaved to jumping up and down in the room i.e. material has absorbed energy.",
"Basically, if there are electrons in a material that are at a certain energy level, and a photon of light comes by that is at the right frequency and energy level, it can hit the electron, be absorbed by it, and make the electron go up to a higher energy level. That electron wants to go back to its lower energy level, so it emits a photon of the right frequency and energy equal to what the electron needs to get rid of to go back down. That light is what you see as the color of an object.",
"Hey /u/Lambert_Lambert did you know the Lambert is a unit of brightness?",
"Think of an atom like a solar system. The protons and neutrons are bunched together in to a ball the middle and the electrons are like planets orbiting it. A planet can get tossed into a farther orbit. We call this a higher orbit because it's like tossing a ball up. It has to fall back down eventually. Lets say an asteroid hits the planet and knockes it into a higher orbit. When this happens, the planet has absorbed some of the asteroid's kinetic energy. Eventually it losses that energy due to other forces acting on it and in the process, it falls back down. Now a photon is like an asteroid. It comes in and hits the electron in to a highet orbit called an energy state. When the electron falls back down, it loses that energy. But it loses that energy by emiting it as a photon with a wave length determined by how far it falls back down. That is the color we see. However some asteroids hit the planet and don't cause it to move enough to see. The planet absorbs the energy and can still release it but it releases it in non visible wavelengths. A lot of absorbed energy gets converted to heat. Heat is the vibrations of molecules and the light emitted is in the infrared spectrum."
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m1bduy | Why is kelp not classified to be a plant but moss is? Kelp seemingly have more plant parts but it is classified as a algae, but moss is a plant? | Biology | explainlikeimfive | {
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"Down at the cellular level, algae and plants are different. There's a ton of confusing overlap so it's not really clear cut but, basically, although kelp has parts that \"look plant-ish\" like \"stems\" or \"leaves\" or \"roots\", if you look at the individual cells that make up those parts kelp and plants look really different. Meanwhile, although moss might not look much like a palm tree, they both have stems and leaves and roots and if you get down at the cellular level they're basically the same types of cells. Basically, plants are using one set of building blocks and algae are using another. Imagine plants are Lego...you can build all kinds of sizes and looks of Lego models but the individual building blocks are all basically the same. Algae are some other building set that's not Lego-compatible, let's call that Algo...you can also build all kinds of sizes and looks of models out of Algo, but you can't connect Algo to Lego."
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m1bo6j | How can someone invent BitCoin and will more keep being "made" if it can all be mined? Doesn't this lead to a dilemma that one day anyone could just print their own money? | For reference, I kind of understand a background that it was "made" and that now a single bit coin is worth a lot of "real" money, but if they originated from a person(s), what is stopping other people from deciding to just "make" their own currency? I also don't understand why people with a great computer background cannot just "make" some bitcoin for themselves by copying it? I really don't understand how a new form of money can just be invented and used to pay for things. > \_ < | Economics | explainlikeimfive | {
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"Bitcoin was designed so that there is a maximum of 21 million bitcoins. After all the bitcoins have been mined, miners will make money off of transaction fees instead of the prize of finding a winning block. You can't \"make\" bitcoin, there is only one way to make bitcoin and that is to find a winning block, which takes a ton of computing power. A new block is \"mined\" every 10 minutes approximately, so every 10 minutes somewhere in the world somebody gets the block reward and everyone knows about it.",
"There were several rival cryptocurrencies a few years ago. BitCoin seems to have “won out” and gathered the most popularity. It’s possible that could change, but not in the short term. BitCoin became popular because people bought into the idea and investors bid up the price. Anyone can invent an investment. The hard part is getting a large number of people to buy it.",
"Bitcoin is only valuable because people want it. Anybody can make a crypto, which spawned a bunch of shitposts like dogecoin, but nobody wanted them so they never racked up any value (the few that became memes notwithstanding).",
"The protocol itself limits the issuance of new Bitcoin, thus ensuring that it's impossible to just arbitrarily print a lot of it rapidly unless you convince all users to switch to a different software (probably creating a fork of the currency) that doesn't have such strictly limits",
"> what is stopping other people from deciding to just \"make\" their own currency Nothing, you would just have to convince other people its valuable so that they would pay you or anyone else for it. But you can create your currency, it won't be Bitcoin of course but you can.",
"Anyone can make a currency indeed. The difficulty is making people use yours and trust yours. Bitcoin does this by having a cryptographic way that prevents \"printing\" any amount of coins, so like gold there is always a limited supply, and then it just became popular through hype. It doesn't even have to be crypto. You can take some nice looking stones, and they become valuable if you convince enough people to accept them as a currency. Bitcoin had it easier though. They were the first of a technology that allows anonymous but still save payment, and they are harder to fake that real money. The only issue is that they have a hard supply limit and that they cost tons of electric power to sustain the system.",
"People printing money is only an issue when that money already has value to begin with. Are you concerned about the people manufacturing monopoly sets printing virtual monopoly money for their games? My guess is 'probably not'. Why not? Because monopoly money is worthless. Yes, it's a new currency, but even if you printed billions of monopoly bills, it wouldn't affect the *existing* economy the way printing new US dollars would. Creating new cryptocurrencies is sort of the same thing. I can spawn a new currency, \"KerslakeKoin\", tomorrow - but it would only have as much value as monopoly money. Now, you could argue that you could run a secret plot wherein KerslakeKoin starts out being worth $10 per Koin, wait for people to have invested $1b USD into it, and then suddenly flip a switch to start printing Koins like crazy, thus inflating it to the point where the $1b invested into it is basically destroyed. But doing this you have a number of concerns: 1. If your cryptocurrency is designed in a way that lets you do this, people will be naturally skeptical to invest in it, so your plan might fail at the stage of even getting to $1b USD. 2. In a decentralized system like a cryptocurrency, the people trading your Koins can just agree to ban you from the system and continue using it as if your massive influx of new Koins didn't exist. (\"hard fork\") 3. You having done this still wouldn't significantly affect the stability of the economy because you haven't created or removed any wealth, you just *redistributed* it to whoever was holding it at the time you crashed the Koin market. While this does technically weaken people's faith in the economy in general, in this case it almost surely disproportionately weakens their faith in the *cryptocurrency* economy, rather than the rest of the USD economy. So your impact on the USD will still be negligible."
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m1cn3r | Why exactly are bitcoins solving problems when mining? | What are the use of the solution to these problems. It's just to verify other transactions? So bitcoins are earned from just maintaining itself? | Technology | explainlikeimfive | {
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"There are two uses...one is to secure the blockchain, the \"ledger\" of all bitcoin transactions that ensures that you can't duplicate them. The solution of the bitcoin mining problem is basically a \"key\" that takes a lot of work to find that semi-uniquely identifies a block of transactions and connects it to the prior block (and, through chaining, \\*all\\* prior blocks). \"Semi-uniquely\" because there may be other solutions that also secure the block, whoever finds one of them first gets it and, once the next block is added to the chain, that's the only solution that will work. To corrupt the ledger would require recomputing \\*all\\* the solutions to all the blocks \"downstream\" of where you want to alter it...that's computationally infeasible, which is why the blockchain is considered secure. As long as the majority of the computers mining aren't corrupt you also can't corrupt the current block because they'll vote out corrupt transactions. The other use is to distribute bitcoins...the only way to create/earn new bitcoins from scratch is to solve the problem. This incentivizes people to mine...so yes, bitcoins are earned from maintaining the bitcoin currency.",
"Simple answer: they do seemingly unimportant but heavy work. This makes sure there is a steady and slow supply of blockchain blocks and new coins. This is important because in Bitcoin, there is no central company that controls your transactions and money (aka a bank). Instead the money and transactions are managed by everyone. Because you can't trust anyone and Bitcoin would not be worth anything if everyone could simply create new Bitcoins, Bitcoin needs a system to ensure that it is really hard to do so. This system is called Proof Of Work. With Proof Of Work, the Bitcoin network tells the miners to make a special calculation/puzzle of which the answer is not known, but when solved, the answer can be easily verified. The miners then start calculating like a maniac. Then at some point, some miner finds an answer. Because the answer can be easily verified the network can then validate the effort and reward the miner with coins. Because Bitcoin tries to keep a steady pace of new blocks/coins the network is self adapting, meaning that it can make the puzzles harder or easier, depending on how often a Bitcoin is mined. Right now Bitcoin is super popular and there are many competing miners, so the network makes it is incredibly difficult to solve the puzzles. This is why miners \"waste\" a tremendous amount of energy.",
"Pretty much, it's just an arbitrary calculation to make sure that everyone agrees on which transactions to include in the blockchain and limit the new supply of coins."
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m1esou | Why does rocking back and forth calm us? Like when a person having a panic attack might rock in place or you would rock a back to calm it when it’s crying or why rocking chairs are relaxing | Other | explainlikeimfive | {
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"When you are anxious, or having a panic attack your body is going into \"fight or flight\" mode. This is an evolutionary adaptation to help us survive a dangerous situation. If you are under threat in the wild your either going to have to run really fast or fight really hard to get out of your situation. Your body get's pumped full of chemicals (i.e. adrenaline and cortisol) to help it move fast, repair itself, and physically take on the threat. Now, this doesn't translate well to when your boss is on your case about a tps report deadline. You are stressed and your body starts pumping out chemicals to take on the threat, but physical activity is not going to help get the tps reports done. You know you need to sit in a chair and get it done, but with those high arousal chemicals circulating through your body, your muscles can't relax. All of that is fact. The rest is my assumption: Rocking is a way to get your body moving and start using those chemicals up. Also the rhythmic motion tells your body there is a repetitive task to do and it can concentrate it's energy on that task rather than telling random muscles to get moving. With the extra energy in your body going to rocking, it allows your mind to focus on the task at hand. Again that last paragraph is assumption based on the previous stated facts.",
"Reminiscent of gently moving/rocking in the warm, safe, cushioned space of the womb while our mothers moved and breathed.",
"Any type of movement will have a calming effect. Often times stress is relieved by an output of energy, which is why exercise is so important to someone’s health. Small, repetitive movements allow for movement and a feeling of control since you are choosing to move in a limited capacity. In terms of rocking chairs or rocking a baby, I’ve heard that the motion is calming because it mimics floating in water. Floating on water can be calming in and of itself. Also babies are floating in water in the mothers womb."
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m1fhrf | How is a computer animated movie transferred to film? I'm thinking of Toy Story specifically. 1995 was before digital projection, so how did PIXAR get the final movie onto celluloid? | Technology | explainlikeimfive | {
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"Pixar developed a laser scanning and printing device called PixarVision. With it they can scan film into a computer and also print images from the computer to film. So the entire film was printed onto master negatives one frame at a time",
"If you printed out the individual frames onto cells such as used with traditional, hand-drawn animation, you could then use the same transcribing process as was used for those animations. Takes a lot of time compared to going directly to digital, but so did traditional animation.",
"Digital projection is much older than 1995, it was based on lasers and much too expensive for people. That's just not how it was done. Toy Story was \"printed\" on film, one frame at a time, by a special machine called a \"film printer\" (not super original name). It wrote each pixel in order, allowing the film to record the light in it's natural grain structure. The file was developed, and processed just like any other movie (they were all made using film then)."
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m1fnfq | How does cryptocurrency like Bitcoin contribute to climate change? | I've been seeing lots of articles about how Bitcoin and other cryptocurrencies are leaving massive carbon footprints that negatively affect the climate. But after doing a little research, I'm still not entirely sure how that connection is made? How is crypto more harmful to the climate than actual paper money, or even traditional digital banking? To me right now, it seems like all these Bitcoin = climate change news stories are being pushed by people or organizations that have a vested interest in ensuring decentralized currency doesn't take off. | Technology | explainlikeimfive | {
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"Mining crypto takes a lot of power. As their value increases, and mining success rates decrease, the power investment required to find each new coin increases. The entire currency is based on burning through electricity to do maths problems. It's environmentally awful, whatever else you might think about crypto currencies.",
"> How is crypto more harmful to the climate than actual paper money Because in order to spend a tenner nobody needs to spend multiple kilowatt-hours verifying it. I just hand over a tenner to the cashier and we're done. In order to create a bitcoin block and be awarded with the mining reward you need to guess a very large random number. This requires spending electricity to have (most often) your GPU cycle trough numbers until you find the correct one. That spends a bit of energy but nothing to write home about. The issue is that a *lot* of people want to be the one to find those numbers, so collectively over the network there are millions of GPU's, entire warehouses worth of GPU's, constantly running 24/7 playing at a giant lottery, constantly guessing numbers day in and day out. That wastes a *tonne* of electricity. The issue with electricity is that quite a lot of it so far is generated with fossil fuels and therefore has a carbon footprint. Bitcoin has a lot of benefits, but in it's current form with the current amount of demand it generates it's really wasteful.",
"The \"mining\" of bitcoins and other similar currencies requires high-powered computers running for large amounts of time all using up electricity and generating heat."
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m1ghgq | how does a powerful earthquake shift the earth on its axis? | Physics | explainlikeimfive | {
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"Earthquakes are caused by the Earths crust moving. Even though the earthquake might be centralized at one location half the contenent might move during such an event. And when a huge section of the Earth is moving around the least thing you would expect is for the axis to shift a bit.",
"The earth spins around it's centre of mass. For the axis to be shifted, the earth's mass would have to be distributed differently. Think of 1 of those cat toys that is a ball with a motor inside of it connected to a small mass...something like this... URL_0 Now if you were to try and rotate that ball in your hand like the earth rotates, when that mass moves inside you feel the ball want to change how it rotates. This is essentially what I mean when I said the earth's rotation can change when it's mass is redistributed. Now while the earth doesn't shift it's mass anywhere proportional to that cat toy, a large enough earthquake can redistribute a fraction of the earth's mass and change the rotation by just centimeters which is only a tiny amount and unnoticeable to us"
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m1hhyv | What is done to crude oil to turn it into gasoline? | Chemistry | explainlikeimfive | {
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"Crude oil is a mixture of a load of different hydrocarbon molecules, for gasoline we want relatively short chains of carbon atoms. All of these molecules have different boiling points so they can be separated by fractional distillation, you heat the crude oil in a fractionating column and boil the components, then you separate these based on the temperature where they become liquid again.",
"There are many processes that takes place at the refinary in order to make sure the gasoline that comes out holds the right specifications. There are a lot of pollutants that needs to be removed, for example sulfur, and some addatives have to be added to get the right properties. But one of the most important thing at a refinary is the destillation column. Crude oil is put in the bottomn of a tall collumn and is heated up to boiling. As the gas moves up the column it is slowly cooled down and condenses. When it condenses it can flow out of the column. Crude oil is a mixture of dfifferent types of oil with various different condensation tempeartures. But when you send it through the destillation column the oil with the highest condensation temperature will condensate in the bottom of the column and the oil with the lowest condensation temperature makes it all the way to the top. So in the bottom you get the thick tar that is used to make asphalt and other stuff. Then you get thick lubricants. Further up the column there is diesel, then kerosine and finally gasoline. At the very top you get natural gasses."
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m1hq4c | How do 3d glasses work and what do the red and blue lines have to do with it? | I remember that when I took off the glasses, the movie appeared to be a red version overlapping a blue version, searched on the internet but it was too technical for me. | Technology | explainlikeimfive | {
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"You're able to see the world in 3D because your eyes see things from two different angles which your brain turns into a 3D image. Color filters absorb everything but a particular color. If you look through a blue filter, you'll see nothing but the shade of blue that the filter is colored with. Movies and videos are 2D since the colors/pixels appear in the same place as viewed by both of your eyes. When you cover one eye with a red filter and another eye with a blue filter, you can display a red and blue pixel in two different places which will confuse your mind into thinking it's looking at a single pixel from two different perspectives. When you see the red version overlapping a blue version without the glasses, you're seeing the intended perspective for both eyes, by both eyes at the same time.",
"The \"left\" view is projected in one colour and the \"right\" view is projected in the other. As you discovered, looking at this without glasses looks like a weird, blurry mess. The glasses, though, filter out the other colour - the red lens only lets red light through and the blue lens only lets blue light through. This means your left eye can only see the left view, the right eye can only see the right view and thus you're able to perceive depth. If you put them on upside down it looks all backwards and wrong and will make you sick."
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m1i394 | How does gene editing function in a living human? I have no idea. Something is inserted into blood? Or into cell? And than this modified cell multiplies? Or what? I don’t know anything about genetics. And possibilites? | Biology | explainlikeimfive | {
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"There's more than one way, but [CRISPR]( URL_0 ) is one of the major ones. Long ago, bacteria got infected by various viruses. The bacteria evolved a defense mechanism a lot like our immune system. It basically checks the bacteria's DNA for virus infections, and cuts them out if it finds any. We copied this natural defense mechanism in the lab, and now we can use it for our own purposes other than bacteria -- it works on insects, plants, and animals. However, instead of looking for a viral infection, we can look for about any DNA sequence we want. For example, if someone has a genetic condition, we can use CRISPR to look for the \"bad\" genes and cut them out. CRISPR works basically like an infection -- you'll get a series of injections, and it will circulate around your entire body looking for the cells it needs to fix. And when fixed cells split and reproduce, the new cells will include the fix.",
"Bacteriophage is a type of virus that attacks bacteria. They shoot into the bacteria cell, just like a hypodermic needle, a strand of RNA (RNA is like half a DNA). This RNA will replicate itself many times and then bust out, killing the bacteria. The bacteria hated this! So what they did is figure out they could make \"special enzymes\" to \"cut\" the RNA, making the RNA not work. Hooray! (these are called *restriction enzymes)* Then us humans (all the way back in the 50's) figured out some of these bacteria were really good at not getting killed by viruses so they figured these bacteria had a special defense. Fast-forward to 1978 (Arber, Smith, and Nathans were jointly awarded the Nobel Prize in Physiology or Medicine) we found out these bacteria used these restriction enzymes to cut the bacteria at the **same place!** This is super important because if this Virus RNA is cut at the same place then we could use these enzymes to cut DNA at the same place. A little DNA background: That DNA helix you saw in school actually has 4 (sometimes 5) base pairs that are always together A-T, G-C. So when you have an A on one side of the helix you got > !a T on the other side. G on one side, C on the other.! < When you line them up they will be AT-GC, GC, AT, AT, CG, etc. So these restriction enzymes \"cut\" at the same AT-GC areas on a RNA which can be used to cut DNA at the **same place!** We essentially use the defense mechanism of a bacteria as a microscopic scalpel to cut up DNA. It's like nano-surgery! But wait, there's more! If we can cut up DNA at certain places then we could \"paste\" in different DNA...but only if we know the special AT-GC code. This is where sequencing comes in. If we have the correct sequence (AT-GC) then we know where the restriction enzyme will cut and what we could put in its place to make different cells! (the DNA paste is called ligase). Now that we got a new cell, lets go back to DNA real quick. DNA is a long helix (like you saw in class) that was thought to be mostly \"junk\" DNA (this isn't correct but it's not important for this). The other areas however, send out Messanger RNA (mRNA) to tell the cell to make a specific protein. These proteins make all the cool stuff in your body. For example, a hormone. So now, let's say you aren't making a hormone very well. What if we took a bacteriophage (like an adenovirus or retrovirus) put our new chopped up-pasted back together-protein making mRNA into it, and let it use it's hypodermic needle to shoot it into our cells. We just load up our syringe and inject it in the blood steam. Sounds great! However, getting it to the right cell is still a little troublesome. There are some real hurdles we still need to overcome before large scale gene therapy is a thing. Hope this helps!",
"There is a great explanation here, on Wired, of the CRISPR gene editing process and how it helps make cells replicate newly modified genetic images. I think they give a better explanation in fewer words that I can!! :-) [ URL_0 ]( URL_0 )"
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m1in04 | Why are stuffed bears more common than other animals? And is this unique to certain parts of the world ? | Other | explainlikeimfive | {
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"Stuffed Bears - or \"Teddy Bears\" are named after US president Theodore \"Teddy\" Roosevelt. The latter was an enthusiastic hunter, but when one particular bear hunt failed to produce any bears for Roosevelt to shoot, his attendants tied a bear to a tree so he could have some form of trophy to take home. Roosevelt staunchly refused to kill the animal as he deemed it an act of poor sportsmanship. While said bear was \"put of its misery\" on his orders anyway, the event sparked a political cartoon, and the cartoon in turn lead to the invention of stuffed bears."
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m1j3yd | How do we know Uranus is spinning on its side? | Wouldnt it, to someone who is just now seeing a planet other than Earth, just look like it’s right side up? Is it visible that it’s different from the rest? | Physics | explainlikeimfive | {
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"Uranus does a full rotation about every 17.25 hours, so any changes are easily detectable. While the visible surface of Uranus is mostly featureless, it's not entirely uniform, so any features can be observed to move as the planet rotates.",
"There is no up or down in space. We usually measure a planet's tilt relative to the plane of the solar system - the plane in which all of the planets mostly orbit. So, most planets orbit and spin in the same direction. Uranus orbits one way and spins another. Hence, it spins 'on its side'.",
"From Earth, no it doesn't look tilted. But then we sent a spaceship/probe, Voyager 2, out and measured and [looked at it]( URL_0 ) close up in 1986.",
"Another clue is that Uranus's major and inner moons all orbit in the same plane as the planet's equator. So we can be pretty sure where the planet's axis of rotation points. (R.A: 257.31 & deg;; Dec: & minus;15.18 & deg;) It's on its side in the sense that all the planets in the solar system, including Uranus, orbit in roughly the same plane. This is what gives the solar system a definition of up or north. In the same way, we consider the earth's axis to be tilted by 23.4 & deg;."
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m1l61c | Why do we never start getting bald from the sides and back of our head? | Biology | explainlikeimfive | {
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"The usual way of going bald is called male pattern baldness, and the traditional crown or front-first loss is the pattern. There are many other ways to lose hair / go bald, and they are usually equal opportunity villains. Alopecia areata is often detected when patches of hair at the back and sides start to thin or fall out, as per your question.",
"A hairdresser once told me that the side of your head is part of your body hair, and only the top was part of your ehh. \"head hair\", thus men only getting bald on top. Not sure if he was full of it or not."
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m1m381 | What are blue balls really and biologically? | Biology | explainlikeimfive | {
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"Blue balls is slang for testicular pain caused by temporary fluid congestion in your testicles. This congestion is often caused prolonged sexual arousal without ejaculation. To put it to analogy, it'd be like if a pipe got clogged because a fluid kept going back and forth in it.",
"There's a huge drop in dopamine levels, akin to losing an important game or project, that occurs when you get horny and then the opportunity for sex passes. That's very real. Dopamine sky rockets when you think you are going to fuck then plummets when it doesn't come to fruition. If you refrain from masturbating or having sex for like , 2 months, your balls can and will swell, but usually you have a nocturnal emission or something before your testicles start to actually hurt or suffer damage. Tl;dr it's real, but not as bad as your boyfriend says it is when he's drunk."
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m1n1t0 | How do government treasury bonds work and how are they profitable to investors? | I am trying to better understand treasury bills/bonds/notes (honestly not really sure the difference between them) And upon googling what the current interest rate on the 10 year treasury rate (Canada) is 1.56% I can’t help but think that you would end up losing money due to 2% inflation every year. I’m obviously missing something here. Can someone explain how treasury bills/notes/bonds work and how they are profitable to investors and how they affect the market ? Thanks | Economics | explainlikeimfive | {
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"The basic idea is that government bonds represent a theoretical “riskless” investment as the assumption is that a government that has control of its currency can’t default - in the worst case scenario, they’d just print more money to repay the debts. As a result, the yields on government bonds represent a pricing benchmark for other kinds of bonds - if the government bonds yield 1.56%, then other bonds presumably have to carry a higher interest rate, as the borrower isn’t the government and can actually default. People invest in government bonds, even if the yield isn’t great, for the reason above - it’s effectively a riskless investment. You obviously don’t put everything there, but it can be helpful for overall portfolio allocation.",
"They are all just loans to the government. Whether they are called \"T-bills,\" \"T-notes,\" or \"T-bonds\" just has to do with the maturity. Bills are short term, maturing in a year or less. Notes have maturities between 2 and 10 years, and bonds have maturities greater than 10 years. Your point about inflation assumes a constant 2% rate, which is not the case. In any event, what is the alternative? If you stuff the money under the mattress, you earn nothing, so you are \"losing\" even more money due to inflation. If you invest in equities (i.e., stocks) you may earn more, but there's also a much greater risk that you lose your money if and when the stock(s) tank - as others have noted, treasuries are the safest investments you can find and are generally considered \"risk-free.\" So it's a trade off: you can either do nothing (and lose most to inflation) or invest. If you invest, you can put money in the safe, yet not very lucrative option or you can choose the riskier, but potentially much more lucrative option."
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m1nlxp | - why is a short piece of thread harder to break than a longer one? | Physics | explainlikeimfive | {
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"Leverage. With a longer piece of thread you can wrap it around your fingers to apply more force leading to it breaking. If it's a small piece of thread you might be able to wrap it around 1 finger at best, reducing the force you can apply."
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m1nxp5 | What about using screens is bad for sleep? | I often hear that you shouldn't look at screens 30 minutes before bed to rest your eyes, which makes some inherent sense, but often paired with that is that you should read before bed. Is scanning ~450 wpm really all that different from watching TV? If so why? | Technology | explainlikeimfive | {
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"Screens give off a lot of blue light, just like the sun. Your body uses the light around you to determine when it's time to go to sleep. Too much blue light confuses your brain into thinking the sun is still out and prevents you from being sleepy.",
"It depends on what you're looking at on the screens. Obviously, if you're looking at a screen showing a picture of the sky during high noon is different than looking at white text on a black background. The problem is, blue light which is present in white light, tricks your brain into thinking it's daytime.",
"Blue light suppresses the production of the hormone melatonin, which is needed for sleep and the regulation of circadian rhythm. Blue light in the morning, like from the sky, causes your circadian rhythm to shift earlier and makes you tired earlier in the evening. Blue light late in the evening pushes your circadian rhythm later. Phones emit a lot of blue light. Also, if your system already has a high amount of melatonin in it, it makes your eyes more susceptible to damage from blue light."
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m1o899 | If atoms are mostly empty space, how can things be solid? | Physics | explainlikeimfive | {
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"Think of a propellers blades spinning around but only way way way way way way way faster, a fan spinning looks like a solid and kind of acts like barrier nothing can pass though, small enough, tight enough together, enough of them, spinning fast enough, and in all directions, solid surface.",
"Take 2 really strong magnets with opposite polarity and try to push them together. It’s pretty much impossible. Atoms are sort of like that, but the forces involved are actually much stronger. In fact, the closer atoms get together the stronger those repelling forces become. Some atoms, like some magnets, are going to attract each other. This is, very basically, why some atoms form materials, such as molecules, with other compatible atoms. Interestingly your question touches on another curiosity of the atomic world that we don’t experience from our perspective. You’ve never really touched another object. There’s always a gap between atoms. But that’s a story for another time.",
"Think of a chain link fence. It’s mostly air, but if you press 2 fences together, they’re solid. At the atomic level, everything is a mesh like that. So when you press your hand up against a wall, the atomic chain mesh of your hand interacts with the atomic chain mesh of the wall, and everything feels solid."
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m1ofk7 | Why does it take so long to change a channel on modern TVs? | Technology | explainlikeimfive | {
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"Old TVs were analog. The signal was encoded in a simple way than needed just basic electronics to decode and display. This was fast, so old TVs changed channels quickly. However, such a method of transmission was inefficient: just one TV channel per frequency. It also did not allow for a high quality of image. The only edge of analog signal is that it is robust: it can be displayed no matter what the interference, it will get blurry, snowy or lose color, but it still will be decipherable. Modern TV is digital, it uses complex computerized encoding that allows to pack ten or twenty channels in one frequency with much more quality. However, deciphering this signal is harder and needs a mini-computer that is built in every modern TV set. That's why the slow down: it's the wait while the minicomputer processes things.",
"Television, both broadcast and cable, is a digital signal. When you switch from one channel to the next, perhaps half a second of data from the new channel needs to be processed before the television can begin displaying video and audio.",
"Most digital TV providers use something called multicast to distribute their programming down to customers. This saves them a massive amount of bandwidth, because only one of each packet (think like a frame of your show) is needed on each circuit. Multicast is built in \"tree\" through the provider network where the source (your channel) is the base of the tree and the customers are all spread out like the branches. When you change the channel, you change to a new tree because you are listening to a new source. This takes about ten seconds to fully establish the new tree from the source to your receiver. In the meantime, your receiver sends a request to the source to get a unicast flow of the channel while the multicast tree builds. A unicast flow means the provider creates a copy of that channel's data and sends it only to you. The advantage to this is that this flow can be set up much faster because no tree needs to be built, so you can start streaming your channel in only half a second or so. The disadvantage is this uses much more data in the ISP network, so the ISP wants you on multicast. After the multicast flow is built, your set top box will seamlessly swap over to the multicast tree, and now you will be part of the exact same data stream that your neighbors who are on the same channel have. ELI5: it takes time to set up the ip data flow for your new channel. First, your set top box performs a direct download of the channel for about ten seconds. This means you get a whole new copy of the data from the channel provider that is built just for you. After those ten seconds, you join a \"room\" with your neighbors so that all of you who are on the same channel receieve the data together.",
"Old school analog channels literally conveyed the signal that was being projected onto the phosphor of the tv screen, line by line. There was no buffering or interframe compression, it arrived at the antenna and immediately displayed, pixel by pixel, line by line. At worst the screen had to wait 1 vertical blanking pulse, \\~1/24th of a second to recognize that the newest data referred to the top info on the screen to start drawing the new picture. Then came digital. The data is still streamed in, but it's not just line by line. It's video format encoded, compressed, and often encrypted, then broken into packets of data for transmission. First, the tv has to acquire enough packet data to know what it has received - reassemble the packets to see how tall and wide the picture should be, the framerate, encoding information, decrypt it (if you have bought the channel or not in your package), and then decompressed\\* to an actual picture that can be drawn on the screen. In the case of a cable box + tv, the cable box then has to take the picture it's formed and RE-ENCRYPT it to go over the HDMI cable for copy protection. Only then can the licensed TV with proper HDCP keys decrypt that signal again to have the picture to put on screen. Basically...a LOT of steps have to happen, and each takes time. \\*decrompression - For a very simple example, for a video of a black screen with a white dot moving in a circle, it's more efficient to transmit 'most of the screen didn't change, just this bit with the moving dot needs to be updated/moved/distorted'. The old school method of sending every pixel of every image one after another just won't cut it. Multiply that technique times a bajillion and you have the modern compression algorithms used for video transmission. Uncompressed there would be no way to fit all the HD video and audio streams down the pipe simultaneously.",
"It's because of how the compression works. Analogue TV sends a stream of analogue information. The channel changes as soon as the TV receives a signal saying it's the start of the image. This will tak 1/60 seconds in countries where they use 60Hz refresh (e.g. North America), and 1/50 seconds everywhere else. Digital TV doesn't send every frame in full detail. It sends a key frame, and the next few frames just show the differences. So it has to wait for a key frame. That will happen a decent fraction of a second later."
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m1ofuo | Why do audio mixers have plugins labeled as multiple channels and how are they utilized? | I look at a 12 channel audio board and I see that there's only 2 inputs; one for channels 9/10 and another for 11/12. What is this and how is it utilized. Its also almost always a 6.5mm input so what does that mean? Thanks. | Technology | explainlikeimfive | {
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"The 9/10 and 11/12 inputs are TRS stereo 1/4\" inputs. TRS stands for tip-ring-sleeve and carries a stereo signal. A 6.5mm connector is a standard 1/4\" cable. Oldschool headphones used 1/4\" connectors, while new headphones use 1/8\" TRS connection. Does that answer your question?"
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m1oia9 | What kind of environmental impact comes about from the tons upon tons of salt that gets added to roadways during the winter, and does it differ based on location (such as proximity to water)? | Chemistry | explainlikeimfive | {
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"I wrote a whole report on this last semester. The short answer: yes. A lot. Salt is really bad for vegetation on the roadside, and any animals in water nearby. And some cities don't really care about how much salt they spread. But other places are looking into alternative deicers.",
"Salt is substantially worse for the environment than sand. Sand was originally replaced with salt because you can *see* sediment being added to rivers and other water bodies as runoff. However, it turns out that sand is easy to remove from runoff, since you just need to slow down the water enough to settle it out. Salt, on the other hand, is extremely difficult to remove (think ion exchange or reverse osmosis). Marine animals (and plants) thrive in different levels of salt in the water. That's one reason ocean species are different from freshwater ones. One impact is that species that cannot tolerate a large change in salt concentration in the water die. I'm interested to learn about other environmental impacts as well, that's just what I know.",
"In Germany it is illegal for private home-owners to use salt on the streets (in *most* communes, I should add) and the cities only use it for specific locations (like, main roads) or even on highways only - exactly because it is extremely bad for the environment and in particular to roadside plants and trees, etc.",
"It's horrible for the environment. If you study sustainability, there are multiple examples of societies being ruined by the irrigation of fields with slightly salty water. Over time the salt builds up until eventually nothing will grow. While a small amount of salt isn't toxic or poisonous, it's the fact that it builds up that's bad. In the city, where many people here put salt on the sidewalk, it builds up in the culverts and drainage ditches and changes what can grow and live (some species can tolerate more salt). Over decades it can make it impossible for some land to grow anything. It can also be washed downstream and build up on farmlands and fields, affecting how crops grow.",
"Depends on the type of salt If it’s those magnesium salts, can erode decade old water pipes and leak lead into the water like what happened in flint",
"& #x200B; I used to live in upstate NY, they started salting the roads right before the 1984 Olympics and have every winter since. They ecological damage to the sides of the roads have been immense. [ URL_1 ]( URL_2 ) [ URL_0 ]( URL_0 )"
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m1oxze | Why do drunk people snore more loud? | Biology | explainlikeimfive | {
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"There muscles are more relaxed which causes the airway to loosen/close up causing louder snoring"
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m1pvz3 | Why do big things move slowly? (Ex: Giant robots or dinosaurs in movies) | I always see movies where big animals or creatures are moving slowly and my first thought is always: why aren't they moving as quickly as anything my size would? Does being big automatically make it slow??? Or is this just a common misconception/trope that we've perpetuated? | Physics | explainlikeimfive | {
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"The amount of force it takes to accelerate something scales with the mass...if it's big, it's heavy, and if it's heavy you need more force to move it at the same speed. You \\*can\\* overcome this by just using a lot more force, but then something called the square-cube law kicks in...the amount of force your muscles can apply scales with the cross-section of the muscles (which is roughly the width squared) but the mass of the thing scales with the volume (which is roughly the width cubed). So the larger you get, the harder it is to maintain big enough muscles to keep the acceleration constant. In practice, you don't maintain acceleration, you see something in the middle...moving somewhat slower, but also gettting much more muscle-y. This is why elephants have way fatter (relatively) legs than horses or humans.",
"This is about reference. Huge mountains in the distance move slowly as you pass them by but the road and trees race past you. Same speed, different size. Watching something that huge move from a distance would be like watching them move in slo-mo. If you’re right next to it though, it will look quick.",
"Basically, big things take longer to speed up than small things, but once they've hit max speed they can outpace most smaller things. That's the general rule, at least. It changes for aquatic creatures and some land animals like elephants who see falling over as an existential threat and so have evolved or of being able to run too fast.",
"Its the same reason a tiny dog looks like its moving very fast when it walks. But unless it breaks into a run you can outpace it simply by walking, although your legs appear to be moving more slowly than the dogs you still are faster. Now just scale that up to a dinosaur. Hes looking at you with your tiny legs moving all rapidly but he can still outpace you with one huge step. It may look slow but its just perspective.",
"small things like insects move very fast (for their size).. elephants move slowly, so do whales. i don't think it's by choice.",
"it's not just in movies, at the zoo i saw a few of those tall yellow long necked horses running, and they looked like they were running in slow motion, it was kinda cool."
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m1q8fc | Why don't flat mirrors also swap up and down? | Also how come when I tilt my head 90° it's still left and right that's swapped in the reflection? | Physics | explainlikeimfive | {
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"My favorite explanation of this phenomenon is that mirrors don't reverse left/right or up/down; they actually reverse front/back. If you face a mirror and raise your right hand, the image raises what looks like a left hand, because the front/back reflection changes the right hand (which is on your right side) into a left hand (still on your right side). The hand looks like it's on the left side of mirror-you, because mirror-you also got flipped front-back, which turned a right into a left. You can see this flipping happening by standing a right-handed glove on a mirror (wrist hole against the glass), and see that the effect the mirror has is the same as if you turned the glove inside-out. Try turning the glove inside out, and watch as it changes from a right-handed glove to a left-handed glove (or vice versa). If you look in the mirror and move your hand up or down, you'll see that the image moves it in the same direction (and that holds true for left/right as well) because the mirror isn't swapping those. But if you move your hand forward toward the mirror, the hand in the image comes toward you (in what you might call the backward direction). A fun experiment is to put two mirrors at a 90º angle to each other and look at your reflection in the seam between them. You'll notice that this pair actually swaps right and left if the two mirrors are side-by-side.",
"Nothing is swapped in any direction on a flat mirror. It is simply reflecting the light rays hitting it back to whichever side they are already on. The concept of left and right is simply what you were raised to understand and when you see what looks like a person in front of you, you mentally swap what you consider to be left and right. In other words, in your reflection, the left side of your body is showing on the left side of the mirror and vice versa. You just mentally think of that as being the right side of the 'person' you are seeing in front of you.",
"Because when you turned around to face the mirror, you turned left or right (like flipping a paper on the long edge). If you turned to face the mirror by turning up/down and standing on your head, the reflection would be swapped up down ( like flipping a paper on its short edge)",
"Ah, this used to confuse the heck out of me. It is *your rotation* from the mirror's position to your own that reverses two dimensions; the mirror only reverses one. A reflection is *not* a rotation - it reverses the Z coordinates, but doesn't touch the X or Y. It's like *half* a rotation - like punching someone's face out the back of their head. Now, how do you have to rotate through space in order to face the way you are, from where the mirror is - do you pitch or do you yaw? If you're a normal human, you will yaw around in a circle on the floor - reversing your X and Z coordinates, leaving Y unchanged. So your X and Z are reversed, the reflection's Z is reversed, so when the two cancel out, you're left with reversed X. If you act like a weirdo and *pitch* from the mirror's position to your own, you'll be standing on your head in front of the mirror - and if you try it, you'll see that up-down is reversed while left-right stays the same."
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m1qfkx | how can scientists tell that a piece of rock is older then the earth | Just saw the post about a piece of proto-something being found in the Sahara desert that is older then the earth. Im just wondering HOW do they know this? Like... Do they have to compare it to other bits of rock that originate from earth or do they have to compare it to rock that came from space, and does it have to be compared to the same type of rock? Im assuming that since its older the earth it came from space right, if not then how is it older then earth? How does the whole process work? Sorry if im not explaining correctly im just genuinely curious. | Earth Science | explainlikeimfive | {
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"[Radiometric dating]( URL_0 ). Things happen to rocks as the planet formed. It sets them in a certain state. Their atoms slowly decay down to another state. For things older than the earth I think they use uranium and lead. When zircon is formed, it can have amounts of uranium embedded within it. That uranium then starts to decay into lead at a very slow, but very predictable rate. We can scan it and find out what percentage is lead and we then know when the rock was formed. > I'm assuming that since its older the earth it came from space right, Yeah, that sounds right. A meteorite for example.",
"If I’m not mistaken, the process to aging inorganic material is sort of similar to carbon dating for organic material, it’s just measuring something different, and by using a slightly different comparison. These processes are called radiometric dating, if I’m not mistaken they measure known quantities of some kind of radioactive material in comparison to its decaying product to estimate how old it is. Carbon dating is similar in that is compared the ratio of two different isotopes of carbon, one which decays, and one which really doesn’t, but are both present in relatively equal quantities so long as an organism is still alive. I don’t know too much of the specifics on radiometric dating though, and I could even be wrong about if that’s the process used for the particular stuff you’re talking about."
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m1qo13 | How do Primate’s understand not to eat a species that is considered Poisonous? | Currently Enrolled in Biological Anthropology & I had this thought while learning about Tarsiers in South East Asia. | Biology | explainlikeimfive | {
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"It might have something to do with members of their tribe eating the said species and then falling sick or dying immediately afterwards. Now primates don't have the necessary cognitive abilities to figure out the causation of the death but if enough members of their tribe die while doing the same thing, a pattern emerges that gradually finds its way into their cognition. Hence, after some years, primates learn to stay away from that particular species. This happened to animals when humans first started becoming cognitively enhanced and animals like goats and sheep didn't know how these puny ape-like animals were killing then by the herd. Gradually, they formed patterns and understood that those particular monkey-like creatures were to be feared. To this day, a stray sheep or goat or cow runs away when they see a human charging them instead of fighting",
"There is some learning and teaching amongst primates about how to survive, including what to and what not to eat. Some of the poisonous plants have recognisable colours. Most poisonous plants will have a bitter taste, so much so, that some smaller animals will try to get the taste of poisonous plants on them to avoid being eaten by predators, or disguise themselves as similar colours to protect themselves. Primates use their sense of taste and recognition of colours to learn to avoid certain poisons in their environment."
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m1rmvt | Why do we consistently find baby animals cuter than adults? | Biology | explainlikeimfive | {
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"Its about evolution. Baby humans as well as baby animals evolved to be what us or adult animals consider cute so that they are driven to want to take care of them. The babies that look cute have a greater chance of survival because its more likely someone will take care of them.",
"Cuteness is a subjective term describing a type of attractiveness commonly associated with youth and appearance, as well as a scientific concept and analytical model in ethology, first introduced by Konrad Lorenz. Lorenz proposed the concept of baby schema (Kindchenschema), a set of facial and body features, that make a creature appear \"cute\" and activate (\"release\") in others the motivation to care for it. URL_0"
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m1s1iz | How does the eye clean itself when lashes, tiny cotton strands, makeup, etc. go on the eye? | One day a small eyelash was on my eye ball and I couldn’t get it out. I blinked and it rolled up inside and was gone. Where does it go? Does the eye do something to ensure it comes back out later through the front? I also wear eye makeup such as eyeliner, mascara, eyelash glue, eyeshadow, etc. and at the end of the day after removal I see black clumps in the inside corner of my eye. I’ll remove those, but I’m pretty sure I’m not getting all of it and a small amount goes into the eye. Where does all this small debris, loose lashes, makeup, go? Does it build up and get stuck in the back of the eye? (I saw some headlines where people have had tons of contact lenses getting removed but my question is focused on small debris like lashes and makeup). Or does something occur where it breaks down this debris? Or does it eventually come out through the front of your eye as eye crust? | Biology | explainlikeimfive | {
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"It all gets washed out. If you pay attention when you feel you have something in your eye, you will notice that your eye tends to water a lot more - this is your body reacting to the debris and trying to help wash it away. Things like an eyelash stuck under your eyelid are a bit more awkward because of the larger shape, but the same still happens - as you blink it will be slowly moved down into the corner of your eye, and it will eventually work its way out of your eye and either fall away naturally, or be brushed away by you without realising. This is why you may also find a small clump of eye makeup appear in the corner of your eye, or the gunk left behind after sleeping - your eye has slowly been washing out any debris that has gotten into it over the day, which will collect at the corner of your eye. As the moisture dries out you are left with the makeup/gunk.",
"There is a clear “skin” over the white part of your eyes called the conjunctiva, and it goes all the way to the back surface of your eyelids. There is no natural connection between the surface of your eye and the back (there’s a lot of muscles and a big nerve back there that would be a big problem if gunk from the front of your eye could travel back and mess with them). I honestly have no idea how that woman had like 10 contact lens stuck in her eye for years, my guess is she had unusually deep eyelids where they could fold up and get stuck. As the other commenters explained, things in the eye slowly travel out towards the nose as your eye water and you blink repeatedly.",
"I don’t have an extensive knowledge of ophthalmology, but I can assure you that there’s a limit to how far above/behind your eye something can travel (it’s a dead end, essentially). Anything seen with the naked eye like lashes, contact lenses, or makeup will eventually stop and will likely be flushed out the front by regular tear production."
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m1sxwp | How does coffee and energy drinks work (in keeping people awake or making them energetic)? | I just labelled it biology, please correct me if that's the wrong flair. Personally speaking, I haven't experienced the delayed sleepiness from caffeine. Even when I drink a mug of coffee, I can just go to sleep directly after 1 or 2 hours. Is this normal or does it take drinking lots to keep you awake? | Biology | explainlikeimfive | {
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"Caffeine (the chemical in coffee, energy drinks, even soda) doesn't make you energized, it makes your brain stop realizing that it's tired, what gives you energy is the sugar. Each person has different \"tolerance\" when it comes to caffeine, but generally the more you drink the less effective it is",
"When we consume caffeinated drinks and foods, our stomachs and small intestines quickly absorb the caffeine. The [maximum effects of caffeine2]( URL_1 ) usually occur between 30-60 minutes within consumption, although this timing can vary widely among individuals. After being absorbed, caffeine is efficiently distributed throughout the whole body, and it crosses the blood-brain barrier. Inside the brain, caffeine blocks adenosine receptors. Adenosine is a [sleep-promoting chemical3]( URL_0 ) that is produced in the brain during our waking hours. Normally, adenosine builds up in the brain the longer we’re awake. The more it builds up, the sleepier we become. When caffeine blocks this process, we remain alert and vigilant. taken from [ URL_2 ]( URL_2 )",
"Caffeine blocks the adenosine receptors. These receptors are one of the way which the body measures time and is responsible for making you drowsy and slow at the end of a long day. It usually starts to take effect about an hour after you have taken caffeine as the drug needs some time to go through your intestines and get around the body to all your cells. So until that happens you will still continue to become more tired. And even when the caffeine takes full effect the adenosine receptors that were already triggers is unaffected and you do not suddenly wake up. This is why coffee is mostly drunk in the morning as it does not help much in the evening. In addition to this people do have slightly different adenosine receptors so caffeine can have different effects on different people. The metabolism rates and the adenosine production can also change over time, often in response to little sleep caused by caffeine. So coffee can have very different effects on different people."
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m1tmkw | fan pulling from heat source instead of pushing through it | Physics | explainlikeimfive | {
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"The heat transfer is being done by convection to the air so it’s the air flow rate that will matter here. So in terms of getting heat into the air being in front or behind doesn’t really make a difference, the air is still being drawn over the element. In terms of the air leaving the fan, it’s able to spread further if there isn’t an element straight in front of it that it immediately runs into.",
"People like to view plastic like it's a single thing. If we talk about metal, there's so many kinds. Aluminum foil, a gold necklace, a cast iron frying pan, and a stainless steel appliance have completely different properties. There are many different kinds of plastic, and they all have very different properties. Some plastics can endure high heat, some plastics will quickly deteriorate with it. With high end computers, we use radiators and computer fans. There hasn't been a huge difference between putting the fan on either side of the radiator and having it push or pull the air. The bigger difference here depends on the specific geometry of the fan blade. Having the fan on the front may allow for the heat source to be more isolated making it less of a hazard if it touches a bed sheet or curtain for example."
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m1tuvf | How come one fruit gets moldy in a bag, but the other fruits next to it can be unaffected by it? Isn’t it infectious (is it the right word, transmissible?) | for ex: an orange | Biology | explainlikeimfive | {
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"The mold is constantly in our air. Usually the mold will start by attacking a damaged part of the fruit, so that part of the fruit may have been damaged which made it easier for the mold to grow."
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m1txf4 | Why is it hard to breathe when you put your head out of a car window? | Other | explainlikeimfive | {
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"Basically, since you are moving trough a fluid (the air) this fluid will apply a resistive force against you, also known as “drag”. This drag creates areas of higher air pressure around the solid body and lower pressure behind (since air can’t pass straight trough your body and “ignore” your existence, it has to hit you and circle around). When you stick your head out of the window your face suffers from this drag and in your face air is denser (thus having more pressure) than the standard atmospheric pressure. Our lungs work by creating pressure differentials between our body and the outside air. When you inhale, you expland your lung’s volume thus creating negative pressure and the air enters your lungs. When you exhale the opposite happens, you compress your lungs, create positive pressure and the air exits. In conclusion, when you poke your head out the window the pressure outside your nose and mouth is higher than the one your body is used to work with, so its much harder for your lungs to create higher pressure than that to exhale."
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m1uffm | How did they make ice before modern refrigerators? | before modern refrigerators and air conditioners people used ice but how was the ice made? | Technology | explainlikeimfive | {
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"They waited for it to get cold and then harvested ice from bodies of water. They would then store the ice in insulated boxes so it would last for a longer time.",
"The classic method was not to make ice, but to get naturally occurring ice and store it and ship to where and when its warm. The scenes at the beginning of Disney's \"Frozen\" where the men cut out ice from a lake and transport it away? That is actually fairly accurate on how it was done until not too long ago. It turns out that you can actually store and transport ice quite a bit without it melting. Store the ice underground in huge chunks and insolate them with layers of saw dust and similar for transport and you could make it stay ice for quite a while. People would harvest ice from lakes in places like the US east coast in the winter and then store it in cellars and ice houses until summer or transport it to where it was needed in places as far away as India.",
"Depends how far back you go. A long time ago they used to collect ice in the winter and store it in underground rooms. The rooms when filled with the ice would stay cold for months and not melt the ice. and so you could keep going in and grabbing some ice for whatever you wanted to use it for.",
"Fun fact: in Farsi, the word for refrigerator is \"yakhchal\", yakh meaning ice and chal meaning pit. Since around two and a half thousand years ago, they would dig a whole and build a dome on top of it with some kind of weird water proof, non-heat-conductive dirt mixture. The holes could contain millions of litres of ice, and the domes could be 10s of metres tall (to keep the hot outside air away from the stored goods/ice). These structures have actually survived to this day. I've been inside one of them. It was full of trash. But the point is there is pictures of them so you can actually see. I imagine this was an idea a lot of cultures would have come up with.",
"Not really that long ago, while my grandparents where alive, they had ice delivered to their house. They were farmers and kept the ice in chests in the cellars. It’s naturally colder underground so they ice lasted a good while if kept properly.",
"Either by storing ice when it was cold enough underground or somewhere insulted, or in some cases even shipping ice from cold parts of the world",
"As u/Larry2Thumbs had said, Ice was taken in huge chunks from different cold parts of the world. These huge chunks would last for months without completely melting. It didn't have to be taken from an arctic region however, it could be taken from a snowy place in the wintertime. They were stored in dedicated buildings called ice houses where it would last through the summer: [ URL_1 ]( URL_0 )"
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m1wonh | How do celebrities keep an income between projects? | Economics | explainlikeimfive | {
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"They might have savings from previous projects, or they do small roles like advertisements, endorsements, guest appearances etc.",
"Not every actress/actor lives in a mega mansion. Many times they are sleeping on a couch or sharing an apartment while doing a lifetime role. Yes they take many crappy commercials or very minor background roles to stay ahead.",
"You need to be more specific beyond just “celebrities.” Actors work differently than musicians or artists, for example."
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m1wq7o | Why cant atoms like hydrogen and chlorine have full shells and not make a molecule of 2?? | What I mean is, why cant chlorine gain an electron to get a full shell without making Cl2 molecules?? Why cant it exist as a single atom?? The same with hydrogen, why does it have to form H2 molecules?? If the element has a full sub shell and is stable, isnt that enough? | Chemistry | explainlikeimfive | {
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"There is nothing that says they can't. But that would only likely happen in a vacuum. The electron they have had to come from somewhere. In your examples, the two Cl and H atoms are basically sharing electrons in a covalent bond. Even if you had a free electron to give them, they would become ions, meaning they would have an electric charge, so would be attracted to positively charged ions elsewhere, forming ionic bonds.",
"Atoms can’t just gain an electron as doing so would make them a charged (negative) species . In order to remain neutral, they also would have to gain a proton, and that makes the noble gas of that shell."
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m1wvo2 | Why does music tempo seem to change when exercising? | Today I was listening to some music. I paused the music, went out for a quick run, and continued listening when I got back. After running, and while I was still out of breath, the music appeared to be playing much more slowly. Why does this happen? | Biology | explainlikeimfive | {
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"A lot of music is based around 120bpm,which is similar to your heartbeat. So if your heartbeat increases it is \"out of sync\" with the music. As a side note: club music is often a bit faster to give you \"energy\" while dancing.",
"It’s just a change in perception. In the same way that adrenaline causes that “life flashed before my eyes” “everything seemed to slow down” affect going out for a run releases some adrenaline so when you came back to the music it seemed like it was slowed down. Everything regarding our consciousness is chemical reactions and electrical/chemical impulses in our nervous system. Since adrenaline causes faster reaction times it seems like everything else is moving slower."
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m1xcf4 | What makes people go flying when they suffer a horrendous shock? | I saw another video where someone was shocked by a power line and flew about 20 feet. I could only imagine it's due to muscles contracting so hard, but I really don't understand it. | Physics | explainlikeimfive | {
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"Your muscles contract because of electrical signals from your brain (typically) down your nerves to your muscles. An external jolt of electricity can still trigger that in your muscles, and yes it can be a very strong reaction. You know how people can perform brief periods of super-human strength when it's a matter of life and death? Well your muscles are always able to do that, it's just too much strain to do all the time. But an external jolt of electricity doesn't care about that. 20 feet sounds a bit much. Person might have hit the ground and skidded or rolled afterwards, or 20 is an overestimate. How and where you get shocked matters a lot. One of the biggest risks of live wires is if one gets into your hand. The muscles contracting could force your fingers to grip onto the live wire, and now you can't let go of it and might instead end up stuck to the power source rather than flying away from it."
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m1y0f3 | Why aren't all sounds "music"? How is it that we perceive some as melodic but most are just noise? | Physics | explainlikeimfive | {
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"It's mostly because of how humans recognize patterns. There's tons of atonal music where there is no key that is followed, but there's still patterns there. Whenever you hear a fan making white noise, there's a pitch there, but you might not find a pattern. Some abstract music might not be considered music by this logic, but that goes deeper than your eli5.",
"Music has an underlying mathematical relationship. Sound is a wave moving through the air, and that wave has a specific oscillation frequency. Higher notes oscillate faster. Notes that pair well together to make chords or harmonies aren’t random, they’re exact fractions of eachother’s frequencies so that the sound waves produce a resonance instead of random interference. To make music, you play these resonant frequencies in a timed beat, or some exact fraction of that timed beat. The key here is that it’s all mathematically related, not random frequencies at random time intervals - that’s just ~~progressive jazz~~ static.",
"I assume because musical sounds (no matter how basic) have some sort of rythym/timing, where normal everyday/random sounds do not.",
"In a word: \"Context\". All sounds produce musical tones which can be tied to a dominant pitch, note, or frequency. With music, we become accustomed to hearing musical patterns and we learn to identify and expect those patterns. Musique concrête (a French term), is basically a style of music that uses noises to make the music. This type of music uses the sounds from machines, hammers banging, or just about anything you might encounter in the real world. **TL;DR** You are used to musical instruments, and traditional rhythms, melodies and harmonies. You \"hear\" that as music. Anything else is just noise.",
"Music is the art of arranging sounds using the elements of pitch, rhythm, dynamics, timbre and texture to create compositions. Using these elements you can create melodies, harmony and rhythmic patterns. This is what we consider to be music. As another commenter said, the human brain is wired to look for patterns and repetition, which is why when we combine ‘sounds’ in this way it creates ‘music’. That being said, I would imagine most musicians would agree that anything that makes noise can be considered ‘musical’. It’s just what you do with it or, what your perception of music is. As stated above, there is a lot of atonal music that doesn’t have such a tight grasp on our western musical norms and can be hard to listen to for some!",
"An oddly similar question was [posted less than a week ago]( URL_0 )."
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m1ymns | How does something qualify as a liquid? Is a sauce a liquid? What about hummus, or a smoothie? When does something become an official ‘solid’ or is there an inbetween state? | Chemistry | explainlikeimfive | {
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"I don't recall the exact point a liquid becomes \"officially a solid\", but I believe it has to do with whether the atoms can move freely among each other. Now as to whether your examples are liquids or not, that likely depends on the granularity you go to. If you pull a single grain of chickpea out of hummus, that's a solid. But hummus as a whole would likely be considered a liquid....or at a minimum \"solids suspended in a liquid\". Interestingly, the TSA rules that hummus *is* a liquid and therefore must abide by the 3-1-1 rule for liquids. Smoothies definitely would be considered something similar, as would any sauces, or gels, or any other similar items. [Here's a fun experiment]( URL_0 ) of very viscous liquids. Pitch...which at room temperature is about 100 billion times more viscous than water, but is still a fluid. It has taken about 87 years for 9 drops to fall from this liquid being held in a funnel."
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m1yn2x | When you get a shot in the arm, how can you be sure the contents are being released into a blood vessel? | When you donate blood the needle goes into a large, visible vein in your arm or hand but when getting a shot the needle just goes somewhere in your arm. | Biology | explainlikeimfive | {
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"Many injections don't have to be directly into a blood vein/artery. Just injecting into muscular tissue alone provides fairly rapid absorption into the bloodstream without the risks of using a vien.",
"There are three ways medication is injected. Most things that are a “shot in the arm” are injected into a large muscle. When they pinch your arm they are locating that muscle to make sure they inject in the right part of your arm. These are called intramuscular injections. Some injections are under the skin which are called subcutaneous injections. Then there are IV or intravenous injections/infusions, these would be the ones that look more like when you give blood. For the intravenous injections there is a needle inserted into a large vein and medication is “pushed” into the blood stream for absorption.",
"OH YOU'RE TALKING ABOUT **INJECTIONS.** ~~Well when you get shot in the arm, the bullet can fragment into little tiny pieces but since your blood vessels will be damaged, it's highly unlikely the fragments can travel through them.~~",
"I'm seeing a frightening amount of misinformation and half-truths that seem specifically written to scare people away from getting injections. Take everything including my post with a grain of salt and listen to doctors for medical advice. The aim of any drug administration is to get the drug into your bloodstream so it can be delivered to wherever in your body it needs to go. How does it know where to go? The drug is designed to bind specifically in that place and will travel around your body via the bloodstream and bind to its target as it passes through. Does that mean that not all drug gets there? Yes, but that's fine, the dosing takes that into consideration. All drug administration eventually leads to getting into your bloodstream and then gets filtered out by your kidneys or metabolized by your liver. The different routes (oral, IV, intramuscular(what OP is asking about) need differing amounts of time to make it into your bloodstream. IV is instantaneous, oral takes one of the longest, and intramuscular is in the middle. If you need a drug that needs to work immediately, like adrenaline, then IV. If you want something that spends a longer time in your body before leaving (which is not a bad thing) then pick a slower route. Blood vessels and capillaries in your muscles absorb the drug absorbed there at a slower rate meaning the full dose doesn't enter circulation all at once. If it did it might not work at all since it would be processed through your body too quickly. Source: Pharmaceutical Engineer",
"Those that are given into a muscle are not supposed to go in a vein. Quite the opposite actually - if it gets into a vein, it can cause a huge amount of damage. The way you can know whether the needle is or isn't in a vein is simple - you just aspire (pull the piston of the syringe). If some blood appears inside the syringe, then the needle is inside a vein.",
"They aren't trying to get it into your bloodstream, they intentionally inject it into your muscle. Injecting a vaccine into your bloodstream could be dangerous as the vaccine components would immediately be carried to all the vital organs, possibly causing damage that could make you very sick or kill you without allowing the immune system to develop immunity to the disease. Injecting into the muscle greatly reduces the spread of the vaccine, keeping it localized to a non-fatal area so the immune system can respond to it and develop immunity to the disease it represents, while also cleaning up and neutralizing the components of the vaccine so they are safer to dispose of via the bloodstream, liver and kidneys. In animal medicine vaccines are commonly just injected under the skin of the animal, as many animals have much looser skin than people and plenty of subcutaneous space. Human skin hugs our muscles and fat a bit too tight so there's not really enough space for subcutaneous injection in most cases, so it is much more effective to just inject it into the muscle. For other types of injections, like medications, intramuscular injections are used to slow the diffusion of the medication into the bloodstream as the effects of the meds can be pretty sudden and severe if injected into a vein. Other types of meds have to be given into a vein because they are too caustic for muscle tissue and could cause severe damage, but vein linings are much tougher and more resilient than muscle tissue.",
"Routes of drug administration: INJECTION Subcutaneous route: The drug is injected in the adipose (fat) tissues right beneath the skin. The drug enters the bloodstream through small blood vessels (capillaries) or the lymphatic vessels. Protein drugs (ex. Insulin) are administered subcutaneously because oral administration results in destruction of the protein in the digestive tract. Intramuscular route: The drug is injected into the muscles (upper arm, thigh or buttock) which lie below the skin and adipose (fat) tissues. It is usually used when larger volumes of drug products are needed. The absorption of the drug into blood depends on the blood supply to the muscle: higher the blood supply, quicker the absorption. Intravenous route: The drug is directly administered into a vein. It is absorbed completely, and is best way to deliver a precise dose quickly and in a well-controlled manner. It is also used for administering irritating solutions that could damage the tissue if administered subcutaneously or intramuscularly. The drug effects last for a shorter period of time and may require frequent or continuous administration. Intrathecal route: The drug is administered between two vertebrae in the lower spine and into the space around the spinal cord. The injection site is numbed using an anesthetic prior to drug administration. This route is used to produce rapid/local effects in the brain, spinal cord or meninges (layers of tissue that surrounds brain and spinal cord).",
"True ELI5 to your question. Imagine your body as a giant, highly populated country. There are roads leading almost every where. Big Veins are like the Interstate or large highway, they carry lots of stuff \"cars\" in and out of the major City's \"muscle, tissue\".There are micro veins \"roads\" running all through the city. If you inject a bunch of cars \"medicine\" in the downtown area they will all eventually make there way to the major highways. Tissue like muscle have lots of roads. Tissue like fat has much less roads but still a decent amount. Tissue like cartilage and other connective tissue have very little or no roads. So some connective tissue that done have roads need off road vehicles \"osmosis, cell wall transport\" to get to the destination. Edit/add more info: others have mentioned that some medicine needs to absorb slowly like Epinephrine for example. If you are having allergic reaction we give a small amount 0.3 mg into the muscle. Your heart will start beating faster slowly as the epi reaches your heart. If your heart stops and we are doing CPR, we will give epinephrine in your large vein, it ~instantly reach your heart. I have seen someone get IV epi while awake, patient said their \"head felt like it was going to explode\" because the meds did absorb slowly. They were fine by the way. If they were older or had heart problem could have gone a different direction.",
"There are four ways medication enters the body through injection. Intravenously (IV). This is in a vein, usually through a temporarily place access point like and peripheral line or PICC line. Its benefits are rapid absorption because the medications don't pass the liver from the stomach. This also limits what medications can be given because some need to pass the liver to not be toxic. You can give continuous infusions or just one push slownor fast. Intramuscular (IM). This is a rapid injection of a small amount of medication into a large muscle like the deltoid, or ventralglutral (butt) muscle. The benefits are similar to IV, the medication does not pass the liver first so it is quicker onset. The limit here is volume of medication, generally less than 3 ml and some medications are toxic to the muscle tissue and can't be used. Subcutaneous (SubQ). This is in the fat with a much smaller needle. This is a bit slower than IV or IM but is good for medications that need a more steady absorption, like insulin. Also needs to be a small amount, usually less than 1 ml. Subdermal. This is below the skin between skin and muscle or fat. Think the TB test or lidocaine. Takes a while to absorbs nd usually reserved for things that stay local and don't get used by the whole body.",
"What would happen if the flu shot was mistakedly injected into a vein?",
"Nurse here, normally when you get a shot in the arm, you don't want the contents to be released directly into the blood vessel. Normally we inject into your arm muscle tissue and retract the plunger, looking for blood return. There shouldn't be any blood return since muscle tissue isn't saturated with free flowing blood. Otherwise, if you do want contents to be released into the blood stream directly then you go for the veins.",
"Man sometimes I forget how American heavy the lingo on Reddit is I was like shot in the arm? Like with a bullet? Then I realised he’s talking about injections",
"Most shots you get don't need to be into a blood vessel (intravenous), but rather intramuscular, into the muscle.",
"I aspirate (drawback) on the syringe prior to administering the medication. Most veins are not deep enough for IM injections. Also, due to the amount of medication being given (in cc) you’re only able to give certain amounts in certain places. 0-3cc Arm and Quad and 3-5cc in Glutes. Also, most medications aren’t able to be given IM or IV respectively. Source- I am a Paramedic",
"You actually don't want a shot to be injected into a blood vessel. A shot requires a slower absorption. There are dosages of medications made specifically for going into a muscle vs going into a vein. If you put a dosage of a medication made for a shot directly into a vein, you could permanently damage the vein or worse (throw your heart into a deadly rhythm for example). You have tiny capillaries that are like baby veins that feed your muscles and the rest of your tissues and organs. They will be the way the medication from a shot gets absorbed. Because they are so tiny it will take longer and you will not get the damaging side effects mentioned above. Source: am an ER nurse",
"to add to what others have said, people know they've successfully hit a vein by pulling the plunger back on the syringe. if blood flows into the syringe, it means they hit a vein, and it's safe to inject. if they arent trying to do intravenous, they'll stick it in muscle or under the skin and pull back to make sure blood DOESNT come in. if a dentist injected novocaine into a vein, it would go through your bloodstream and into your heart and cause a big problem. they want it to be local, so the dentist is supposed to pull back on the plunger before inejcting to make sure they didnt accidentally hit a vein. you'll see the plunger pull-back depicted from time to time in shows like breaking bad. an addict does intravenous injection, and they're usually amateurs, so that's how they know they hit the vein",
"There are a lot of drugs that can go multiple routes to get in your body (into a vein, into a muscle, into fat, oral, sublingual, etc). There are also a lot of drugs that have to go a specific route because of how the body breaks them down or the effect they can have if they are particularly harsh. Like you give insulin into fatty tissue because of how the body can use it. You can also give insulin straight into a vein during emergency situations because it works faster that way. You can give certain nausea medicine (phenergan) into a big vein and into the muscle, but you can't give in fat because it is too harsh and will tear up your fatty tissue. Vaccines are designed to go into muscle. But typically the muscles we use for vaccines aren't particularly vein-y. If you were to accidentally give a vaccine in a vein, it would likely be okay, it just might mess with the effectiveness of the vaccine.",
"There are different administration routes for different medications: Intramuscular (Inside the muscle) Subcutaneous (below the skin, more exactly, in the dermis, wich is the layer below the epidermis, the outermost layer) Intradermic (just below the epidermis, in this the liquid accumulates and forms a papule, the liquid raises the skin) Endovenous (this one goes directly into the vein, and has to be applied on a visible vein, it can be straight from through a needle or an IV line) The way in wich you apply a certain medication depends on the composition of the medication, and the effect you want it to have. For example, one type of penicillin is applied intramuscular because it forms a complex once applied wich releases the penicillin molecule over time, wich can last up to 21 days. Another type of penicillin is applied endovenous, and has to be applied several times a day because the effect of penicillin doesn't last as long. Both are penicillin, and the effect of the molecule is the same and lasts the same in the bloodstream, but in the first case the molecule is slowly released into the bloodstream and in the latter it gets directly to the bloodstream. In the case of vaccines, what you want is to get the cells of the immune system to \"catch\" the antigen (the part of the vaccine that you want to generate immunity against) and recognize it so that the immune system can start producing antibodies against it. The effect wouldn't be the same if applied directly into the vein, and in the case of some vaccines that are attenuated virus, you really don't want the virus directly into your bloodstream, wich is why when the needle is inserted in the muscle, the person applying the vaccine first pulls the plunger to make sure the needle isn't in a blood vessel. Edit: typo",
"Nurse here. There are several different types of injections. and not all are supposed to go into the blood. Some need to be under skin or in muscle tissue. The most common are Subcutaneous, Intramuscular and intravenous. The choice on which to use if often dictated by the medicine type you are using. IV meds, for example, bypass the liver until they have been circulating for a while where the oral version would go to the liver first. Some meds do not work against an organ, but against a system. Think of a vaccine. you want your immune system to respond to it before your body metabolizes it out. So for the types of shots, you have Subcutaneous. This is a shot into the layer just underneath the skin, between the muscle and the skin. This is for things like insulin, heparin. This is usually done in the belly or behind the arms maybe even the thigh. It uses very short needles. Next is IM, or Intramuscular. this is into a large muscle mass and is usually what people think of when they are going to get a shot. Vaccines are placed in the deltoid muscle near your shoulder. Antibiotics, steroids and hormones, in general, are placed in your gluteus medius muscle or your ventro gluteal muscle near your hip. If you are self injecting, or giving big shots (more than 1ml volume) to a child, often this goes into the vastus lateralis muscle in the thigh. This is for when you want the medicine to enter the system a bit slower Next you have IV injections. This is directly into a vein. This is typically how you will receive injections if you are in the hospital. We insert an IV catheter, which is a soft plastic tube, into the vein using a needle then remove the needle. This has what is called a saline lock attached to it which we fill with a saline solution to help keep it from clotting and a valve in it to keep it all in. A syringe can screwed to the saline lock and we can give you medications directly into the veins. We used to aspirate when giving an IM shot...that is, pull back on the plunger to see if we get blood. this would mean we are in a vein or artery. this isn't taught any more as the focus is more on placement in areas where there are no larger vessels to puncture."
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m1zirr | Why is it that some injections (IV, heroin) require a vein while others (epinephrine, shots) can just go in a muscle? | Biology | explainlikeimfive | {
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"It's mostly a function of where the injection is supposed to act. Heroin is taken to goof with your brain, so it needs to get to your brain. Doing so via your blood is its best bet. A vaccine on the other hand wants to interact with your tissue or lymphatic system in order to trigger an immune response. This is a lot easier to achieve if it gets injected into a muscle. Epinephrine is a bit of a weird one. You can give it into a vein, and it works really well if you do it right but there are other considerations. The standard form a lot of people are familiar with is an \"EpiPen\" which is designed to be used by someone who is in the middle of a serious medical emergency, so \"jam it into your thigh\" is chosen as a balance between effectiveness in getting the epinephrine into your blood system and ease of use. The other thing about epinephrine is that it doens't last that long once it hits your blood stream, so if you want to give it in a vein its usually as an infusion, again not something that Mrs Sally the kindergarten teacher is going to handle when Timmy accidently has peanuts. Sticking a large dose into your muscle and then allowing it to 'leak' into your blood over time achieves roughly the same effect that the infusion would.",
"If you need the drug to work *right now,* like your airway is closing and you have a trained person who has put the needle in the vein properly - then you shoot it into a vein. If you can wait a minute or two, it is easier and pretty safe to put it into a ~~fatty~~ muscle tissue like your butt or leg. In fact, in the military you are trained to stick yourself in the front of your leg if you are exposed to nerve gas and you would think that would need to go into a vein but the effects go pretty quickly. I was reading a story of an ER doc that accidentally stuck herself with an epi auto-injector and she was hyped up for a few hours. That went into soft tissue and she felt the effects almost right away. Morphine doesn't have to go to into a vein, when I had a kidney stone and I was waiting for treatment the nurse came in and basically said \"let me see your butt-cheek\" and she stuck me. You know what, I got relief pretty fast."
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m20c3u | What is Survivorship bias? | Other | explainlikeimfive | {
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"Survivorship bias is only looking at data points that have already passed a certain qualifier, without considering why they \"survived\" to that point in the first place. A classic example: * In a war, planes that return from missions are often full of bullet holes all over the wings, with almost no bullet holes along the body. Where should you add armor? * Many people will immediately say \"all over the wings\", since those are the parts that returned all shot up...but survivorship bias means that the planes that made it back with lots of damage were the ones able to take that damage *and still make it back*. * The real answer is to add more armor over all the parts that *weren't* shot up when the planes returned - because planes that took damage in those areas *didn't survive to return in the first place*.",
"“Kids today are so soft! Everyone making a big deal about helmets, but when I was a kid, nobody wore them and we all turned out fine!” Well, no. That’s not true, but the ones who didn’t turn out fine aren’t in a position to speak up for themselves. Survivors sometimes get more attention because they can speak for themselves, when casualties may have had something more valuable to say.",
"Survivorship bias is when you’re collecting data only from a “surviving” set of the original group, and so your results are skewed. A rather infamous example comes from WWII - British bombers returning from flights over Nazi controlled Europe were often peppered with damage from German flak and interceptors. Some areas were often heavily damaged, others only rarely. So you add armor to the most frequently damaged areas, right? British engineers did the opposite: armor up the locations that were never damaged. Why? Planes that were damaged there never made it back, and the returning planes were merely a survival-biased sample that got damaged in less critical areas. You’ll often see this type of bias in advice articles about what pro-athletes or millionaires do - the advice doesn’t necessarily work, you’re just ignoring the thousands who failed.",
"It is the idea that you have to be careful when looking at groups of people or things at a certain point to make observations about that group. You are only observing the examples that made it that far and those can be quite different from the group as it started out. This does not has to be literal survival, but can be all sorts of things that filter out the examples you observe. For example, when looking at old centuries old buildings in Europe, one might easily come to the conclusion that they must have build them really sturdy back in the day if those buildings are still there. However you only look at the buildings that survived to the present day and not any of the many that didn't survive. It is like hearing the founders of various start-up companies that became successful talk about what they did and trying to base your own strategy on that without ever considering all the failed startups. It is asking all the students at the end of a semester wether they found the course too hard without considering the students who dropped out along the way. It is asking a bunch of people who lived to 100 about their habits and trying to get from that which habits make you live longer. It is looking at reports from veterinarians about cats who fell from different heights to make observations about what sort of falls are surviavable for cats, without ever considering that people don't take dead pets to the the doctor. You always have to keep in mind that when you look at a group of things or people or whatever, you only look at the part of the original group that made it to where you look at them. This always involves a bit of a bias. Marathon finishers are on average healthier than marathon starters and if you exclusively interview lottery winners about how long they played before they won, you will get the wrong idea about your chances of winning the lottery.",
"Funny, everyone used the same example. The person who recommended the armor placement on WW2 planes was a mathematician named Abraham Wald."
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m20jmz | i thought serotonin made you happy, but antidepressants block it? | Biology | explainlikeimfive | {
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"SSRIs don't really block serotonin from where its used, they block the reuptake (hence the R in SSRI) so that the serotonin stays available to your system. Basically your body will stash the serotonin for later if it feels like you're done with it, even if you're not done using it. Instead of stashing it away, SSRIs will just leave it out until we use it all. The stashing is what we block. We do not block our body from using it.",
"Zofran is only blocking seratonin in a specific type of receptor. It does not block any receptor. This type of receptor is primarily found in the vargas nerve which can trigger vomiting. Blocking this receptor prevents certain types of vomiting from happening. We do not know exactly how all the nerves is connected and how they use different hormones like seratonin and dopamine. But the receptor you are blocking with zofran have nothing to do with the feeling of happieness."
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m20o3r | Can our brains keep track of time while being asleep ? | If you set up an alarm for 10 days to wake up at 8 a.m. and then don't to do it one day, your brain will wake you up at 8 a.m. This happens to me, at least, every weekend and I'm wondering if our brains are capable to keep track of time while being asleep. | Biology | explainlikeimfive | {
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"It has more to do with routine than \"keeping track of time\" to my knowledge. Your brain isn't thinking \"okay it's 8am, time to wake up\", it's thinking \"okay I've been asleep for about as long as I normally sleep, time to wake up\". If you were to wake up every day at 8am, then travel to another timezone and go to sleep with you normally do, you would most likely sleep about as long as you normally do even if that means you wake up at 6am local time or something."
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m20u62 | Why do certain medications of the same dosages vary drastically in size? 25mg of one medication may be very small while another 25mg pill might be very large? | I’ve asked my doctor who said— “I don’t know! Good question.” And then a pharmacist who gave me an answer that made no sense. Some medication can be 2mg and a large pill while a 50mg tablet of something else can be *super* small. I’m guessing this has to do with fillers? Why would you need different amounts of inert fillers and what purpose do they serve if that’s the answer? Are different compounds a different size? Lots of questions. I’m confused. | Chemistry | explainlikeimfive | {
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"The number is just the amount of active ingredient. The tablet size will include the active ingredient as well as other stuff. These could be \"filler\" but are likely there for some purpose. URL_0 The excipients can include diluents, binders or granulating agents, glidants (flow aids) and lubricants to ensure efficient tabletting; disintegrants to promote tablet break-up in the digestive tract; sweeteners or flavours to enhance taste; and pigments to make the tablets visually attractive or aid in visual identification of an unknown tablet.",
"The majority of a pill isn't the active medication, but binders/inactive ingredients. They allow the pill to keep shape and remain shelf stable, as well as meter out the release of the medication over time as the pill dissolves... some medications may want to get it all into you as quickly as possible, while others want a slow and steady absorption. And some pills get taken on shorter cycles than others."
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m20vd2 | why is it easier to look at the sun at dawn even if you can see its full shape? | Earth Science | explainlikeimfive | {
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"Compared to when the sun is directly overhead, when it's close to the horizon, the rays of light go through much more atmosphere before reaching your eyes. More atmosphere means more deflected light (thus the pretty colors!), less intensity, and easier on your eyes."
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m21z0r | Why do we stop being hungry after not eating for a long time? | Biology | explainlikeimfive | {
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"You are still feeling hungry but your brain suppresses it cause you should focus on some more important things like finding foods. Being hungry for a while is enough to remind you that you need foods and there is no good to be suffering and focusing on the stomach. What if there came the smell of fried KFC chicken legs when you thought you have passed the ''hungry period'', your mouth would also get watering and your stomach would start telling you how hungry you really are by roaring and twisting."
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m222qn | What is entropy and why does it happen? | Physics | explainlikeimfive | {
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"Entropy is just a quantity that a system has, like energy, it’s just a number which we can use to describe a system. There’s a few different ways to define entropy but the most friendly is as a measure of disorder, a system with low entropy is ordered and regular (think a new pack of cards) a system with high entropy is random and disordered (a shuffled pack of cards). Like I said entropy is just a quality of a system, it doesn’t really make sense to ask why it happens, what you’re probably asking about is why entropy increases. The second law of thermodynamics is that in a closed system entropy always increases and you can justify it from a statistical perspective; if you have a new pack of cards and start shuffling it then you’ll go from a state of low entropy to a high state, theoretically you could shuffle it back to being in order but that is incredibly unlikely. Similarly a system high in entropy could spontaneously return to low entropy but it’s incredibly unlikely, over time it will always increase.",
"Put a bunch of white marbles in a container up to the halfway mark. Now put a single layer of red marbles all the way across, then fill the rest up with more white marbles. Now, shake that container around. The perfectly flat layer of red marbles pretty quickly breaks up and the reds start getting mixed in with the whites. Entropy is: is there anything you can do to make the reds go back into that single layer in the exact middle again? Nope. Anything you do will only make it more and more *disordered* \\- that *highly ordered state* that it started in ain't ever coming back.",
"Entropy is often described as the amount of disorder. I say often. I'm going to link to Steve Mould's video of [A Better Description of Entropy]( URL_0 ), but I'll continue with the regular one. Suppose you have a box with a lot of coins in it. They're all lying flat on the base, all showing heads. This is a very ordered state. There are only two states where the coins are as ordered as this, the other being that they're all tails. If you threw the coins in to the box, the chances of them all landing the same way (either all heads or all tails) is tiny. Most likely, some would land heads and some tails. The reason this is the most likely outcome is because there are lots of different ways of having them mixed, but only two states that are \"ordered\". So, any action that can shuffle the coils, like you bumping the side of the box, will likely cause some of the coins to flip and end up in a less ordered state. Say you've got 100 coins and one is tails, the others heads. Suppose you bump the box with just enough force that one coin flips. What would you expect to happen? The one coin turns to heads and everything is the same? Or that one of the other 99 coins flips, and you now have 2 coins showing tails? Obviously the second is more likely. Each time something happens to the box, it's more likely to head to a \"disordered\" state where it's roughly 50/50. The disorder is just the natural consequence of random flips. Now let's move to 3d. Suppose you've got a box full of table tennis balls. Half are painted red and the other half blue, and the red balls are all at one side of the box. Every time the box gets jostled, the balls will become more mixed. Eventually, you won't be able to tell which side is which. This is like hot and cold things mixing. The temperature spreads out until everywhere is the same temperature. You *can* sort the box out again (which is what a fridge does), but it takes effort to do this, which uses up more energy from somewhere else (you)."
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m224wj | Do atoms last forever? | Chemistry | explainlikeimfive | {
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"Maybe. Some atoms are highly unstable and last for mere fractions of a second before shearing apart into smaller atoms. Some are highly stable and will last for many times the current age of the universe. The hydrogen atom is just a single proton, and the proton is so stable that we’re not sure if it decays. Some models suggest it does, but with a half-life orders of magnitude longer than the age of the universe. If that’s true, then at some point in the *far* distant future many quadrillions of years after every star has burned out, the protons themselves will decay."
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m22tti | What exactly is an allele? | Biology | explainlikeimfive | {
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"I think, if you imagine an allele is like a particular ticket, or group of tickets, in a line of unrolled mostly pink tickets. The allele’s specific ticket(s) would in this case, be colored green instead of their surrounding pink, and that represents the allele for example, Green Eyes. Then, there is the other alleles for the same “type” of trait, Eye Color, which will also be an unrolled line of mostly pink tickets. But this time, the allele is a group of blue tickets, in the same spots the green ones were in for the other roll. This blue allele, codes for Blue Eyes. In more scientific terms, the allele is the variation of the type of gene. So blue or green or brown or gray eyes, but they all have to do with the same trait, eye color. And the allele is an “area” on the DNA that controls the eye color. Now, eye color isn’t actually that simple but i think it’s useful for seeing it, at least for me. I hope that helped!",
"Alleles are different forms genes for the same characteristics Example Brown eyes = B — Blues eyes = b Both allleles code for a eye colour, and the “flavour of gene” is the actual colour you get. You then have dominant alleles and recessive/passive alleles. Brown is dominant B — Blue is recessive b If mums egg has the blue eyes gene - b And dads sperm has the brown eyes gene - B That baby WILL have brown eyes as the brown is dominate. Has the brown allele and the blue allele (genotypes Bb) and the phenotype of Brown",
"Let's make an analogy with cookbooks. Imagine you have a cookbook. This is a chromosome. In this cookbook you have different recipes. These are genes on the chromosome. Imagine one of these recipes is for apple pie. Now consider that there are many different recipes for \"apple pie\"...slightly different ingredients, different cook times, different spices. You could even imagine a recipe for apple pie with a typo that means the recipe totally fails to make a pie, like \"leave in the oven for 30 hours\" instead of \"30 minutes\". These different variations on apple pie recipes are different alleles. You only have one apple pie recipe in your cookbook, just like you only have one allele for a particular gene on your chromosome. But you have two copies of each chromosome. You can think about this like getting the family cookbooks from your mom's side and your dad's side of the family. And each family might have a different apple pie recipe. So you might have two apple pie recipes, or two copies of the same recipe. This is like having two different alleles or two copies of the same allele. Ok, now what about dominant and recessive alleles. There are different ways to get this, but the simplest works like this. Imagine you are going to make apple pies. You need 10 apple pies. There are two possible recipes, one good apple pie recipe and one with a typo so it fails to make apple pies at all. When making apple pies you don't want to show favoritism so you always alternate between recipes. If you have two copies of the \"good\" recipe, you make 10 pies no problem. If you have one copy of the \"good\" recipe and one of the \"typo\", it takes a bit longer because half your apple pies fail and get thrown in the trash, but you still eventually get to 10. If you have two copies of the \"typo\" recipe, you never make 10 pies and don't have apple pie. In this case, \"good\" is dominant over \"typo\"... as long as you have at least one copy of \"good\", you still get 10 pies."
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m23eui | Why are some simple games (sudoku, bubble shooter, card games) perceived as soothing or relaxing? | Edit: title should have said can in stead of are, sorry! I have a feeling it has to do with our brain but would like to know what exactly happens while playing these games? | Other | explainlikeimfive | {
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"Your brain is hardwired to find problems and solve them - issues in our brain cause some stress, and solving them, taking them off of our plate, causes a feeling of relief or catharsis. This is caused by a dopamine release in our brain - it's your brain rewarding you for solving a problem. Puzzles and games are built to trigger this response. They might be tricky or take some time, creating a small stress response in our brain, but once the solution is found, we can take that dopamine hit in our brain and feel satisfied that we solved a problem. Especially in the modern world, where so many people are dealing with problems that don't have an obvious or a simple solution, it can be really rewarding to sit down for a few minutes and deal with something that *does* have an answer."
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m23wf4 | How does a car radio know the name of the station, and the song playing ? | Technology | explainlikeimfive | {
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"text": [
"There is a standard for this called the Radio Data System. It is a low bandwidth data signal that is sent on the audio but at three times the frequency of human hearing. So people can not hear it but a chip in the radio will be able to decode it. There is not much bandwidth but it is enough to transmit some simple text messages for the front display, the time of day, other radio transmitter nearby in case the signal fades, traffic information to the satnav, etc. A very similar system is also used on DAB radio to transmit the same information. However on DAB there is a bit more bandwidth and you can actually transmit small images as well so a DAB radio might show you some album art or the logo of the show as well."
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m23z7u | Just discovered I brought bedbugs back from an Airbnb so I figured I'd ask a light question about it. How do really small creatures travel those high distances within the fabric (bedsheets, carpets etc) which to them would look/feel like a gigantic Ninja Warrior course ? | Biology | explainlikeimfive | {
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"Did you get your money back? I think this could be a yelp review rather than a reddit post. Maybe even a sternly worded letter to a congressperson tbh."
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m24aiv | In movies like Pulp Fiction they show EpiPens being jabbed in the centre of the chest, but through the breastbone? How is it possible for the needle to actually withstand the force of John Travolta overhead swinging it against solid bone? Is it just fiction? | Biology | explainlikeimfive | {
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"What you see in the movie is not an EpiPen but a regular syringe with epinephrine. At the time of the movies release EpiPens had just been on the market for a few years which is why when they wrote the script they had them use the old style syringe instead. Secondly this is not how you would administer epinephrine normally. The only reason to inject the drug into the heart instead of a muscle is to make it act faster which can help if it is a matter of seconds. And if that is the case the needle may have to go through some cartilage but not through the main bones in the rib cage. The needle may therefore be thick enough to handle this. But I have not heard of any emergency responders doing this for any reason. There is one emergency procedure where you put an IV into the bone marrow which is the best place to put an IV if you want to give the patient a lot of fluids to keep their blood pressure up. However they drill a hole in the bone first before they inject the needle. Another thing that the movie gets wrong in this scene is that the patient is miraculously cured by the epinephrine injection. Epinephrine may delay the effects of the drugs but will quickly wear off. In addition epinephrine can have other nasty side effects. So an EpiPen is only used to buy time before the ambulance arrives and will not actually cure the patient.",
"Mostly fiction [intracardiac injections]( URL_0 ) were a real thing where an injection is sent into someone’s heart. But they didn’t go in through the chestbone. They went through the “intercostal space” which is just below the collarbone and slightly off center on the chest. In real life field administration of Epipens is to the meaty bit in the leg below ones butt. ANYYYYWAYYY this would not be the approach for an Overdose like the one Mia is experiencing, Narcan would be the course of action which is administered via nose spray for most untrained rescuers like Mr. Vega"
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m2575f | What's so bad about Florida that it bears the brunt of all "state" jokes? When was this legacy / reputation immortalized? | Other | explainlikeimfive | {
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"Florida has \"sunshine laws\" which make many official records open to the public (in other words, they're doing their government business \"out in the sunshine\" where everyone can see). This also means that the public has easy access to court records. Stupid shit that people do all over the place, is *publicly-documented* stupid shit in Florida - it's not that people there are dumber, but more that everyone can *see* the dumb people there.",
"To elaborate on the \"sunshine\" laws. If a cop goes out for a domestic disturbance call, another state may have public records that say there was an incident and the results. Florida would give details like: \"Man stabs roommate with squirrel for taking last beer.\" Or an \"altercation in a drive through\" would be the much more exciting \"Man throws live alligator through window at Wendy's\" I'm not saying we're NOT crazy down here in America's wang. But other states are way better at hiding their crazy."
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m25ejp | Why do we have two nostrils? | Having two eyes gives us the ability to interpret depth, two ears help us locate where a sound comes from. What about our nostrils? | Biology | explainlikeimfive | {
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"To improve our sense of smell. Obviously we need to breathe in air to live, but in doing so we also breathe in lots of particles that contribute to what we smell. Not all particles/chemicals are absorbed by the nose at the same rate, some absorb fast, some absorb slow. The fast absorption works fine for the \"active\" nostril (the one that most of the air flows through at the moment), but it isn't very good at absorbing the slow ones. So one of our nostrils is pretty much always restricted so air flows more slowly through it and kinda lingers (when compared to the other nostril). This gives more time for it to absorb those slower absorption particles, which allows us to more easily detect and identify them. tl;dr - Not all smells are equal, if we only had 1 nostril we wouldn't be able to smell as well because of how we naturally breathe."
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m25of0 | I've been looking at buying a house lately and general consensus is that a South facing garden is best.. As the sun rises in the east and sets in the west, why would a South facing garden be any better than a North facing garden? | Other | explainlikeimfive | {
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"The advice for a south facing garden is if you live in the Northern hemisphere - in the warmer summer months, when the sun is further to the south (not directly over head), a south garden will have many hours more sun than a gardon on the north side of your house which will be shaded for several hours a day by the house itself. If you lived in the southern hemisphere, the advice would be opposite - you want a garden on the north side of your house. In the warmer winter months, the north side of your house will have longer sunlight hours. The effect of a south/north facing garden becomes exaggerated the further from the equator you live. If you were to live in say Scotland, a north facing garden would be in shadow (from the house) for a significant portion of the day, only getting direct sunlight for an hour or three around noon.",
"A south facing garden is better because the sun moves from the east to the west...sort-of-above the equator. So...the part of the property that points in the general direction of the equator gets more sunlight than the side of the house that is constantly somewhat shadowed by the house.",
"Because in the northern hemisphere, the sun is in the southern sky. During the summer, if you look up at the sun at it peak, It may look pretty close to directly above you. but, for most of the year the sun isnt at that peak, the path it takes across the sky is actually lower. And if you're in the northern hemisphere, then the sun is in the southern sky, which means your house is going to cast a shadow to the north, obviously the shadow will change throughout the day as the sun moves from east to west, but it will generally be cast to the northern side of the house. therefore, any garden up against the north side of your house is going to get less sun than any garden up against the south side of your house. edit: this also gets more extreme the further north you get, though it gets very strange if youre actually far enough north that the sun never sets, but thats a whole other thing.",
"South facing gardens are for places in the Northern Hemisphere. In the Northern Hemisphere, the arc of the sun means that it generally takes a path such that it curves more south than the user's relative ground position, so the south side of a house would experience more daylight, whereas on the north side, there's likely going to be more shade.",
"This assumes you are living in the northern hemisphere. The sun is always to the south. A south facing garden gets sunlight all day. A North facing garden would be in the shadow /shade of the house.",
"The sun *doesn't* rise in the east, *doesn't* set in the west, and doesn't travel directly overhead between them - at least, not in most places and on most days. The only place and time the sun does all of these things is at the equator on the equinoxes. The solar track in the sky begins somewhere near east (north of east in northern hemisphere summer, south of east in northern hemisphere winter), arcs southward (if you're in the northern hemisphere), peaks in the southern sky (if you're in the northern hemisphere), then sets somewhere near west (north of west in northern hemisphere summer, south of west in northern hemisphere winter). Unless you're in the tropics, the sun is never directly overhead and spends most of its time in the hemisphere in the direction of the equator (south in the northern hemisphere, north in the southern hemisphere)."
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m26dcd | What is a partition coefficient (pharmacology)? | Chemistry | explainlikeimfive | {
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"In chemistry, a partition coefficient is the factor by which an element or molecule moves from one phase to another. So you could have two separate phases in equilibrium with each other and a certain element might prefer to stay in the phase it started in (bound to some molecule or other), or it might prefer to enter the other phase. In pharmacology, this is routinely applied to how readily a drug will cross the relevant cell membrane or how easily some drug moves between different phases in the body. An example would be an anaesthetic drug, for which the blood:gas partition coefficient for the drug is what will dictate whether it stays in the blood (high partition coefficient) or easily moves into the gas phase (low partition coefficient). Partition coefficients in pharmacology are an essential part of understanding how drugs move around the body and how persistent or easily removed they are from the body."
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m26qkq | How can objects like laundry machine buttons ‘beep’ when they don’t have a speaker to emit the sound? | Technology | explainlikeimfive | {
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"A lot of consumer electronic devices do have a [piezo-electric speaker]( URL_0 ). It can't reproduce complex sound like human speech, but it can make beeps. The speaker may be hidden behind a plastic control panel and still be audible. There is a [microcontroller]( URL_1 ) (tiny cheap computer) that detects the button presses, and in addition to turning things on and off in response to the buttons (and perhaps activating lights or a small display), can send a [square wave]( URL_2 ) to the piezo-electric speaker to make a beep. The frequency of the wave can also sometimes be varied to make beeps of different notes.",
"They have a sound maker, it just happens to be inside the cabinet. Mostly this is to keep it dry and protect it from soap, lint, finger-poken, etc."
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m27h5m | How Bond yields affect the mortgage industry and interest rates. | Economics | explainlikeimfive | {
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"Bond yields are how much interest the government is willing to pay for investors to buy its debt. If interest rates are too low, the government may not attract enough investors to continue buying its debt and thus need to increase it to make it more attractive. This interest rate is tied to the interest rate banks pay when borrowing from the government to secure mortgages. So if the government raises interest rates, it makes bonds more attractive to investors but also makes borrowing more expensive for those looking to secure loans from lenders."
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m299wo | How do seemingly stationary/well balanced objects suddenly fall over? | Physics | explainlikeimfive | {
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"It wasn't well balanced. Small earthquakes you probably don't even feel happen all over the world all the time. Houses also settle pretty much infinitly. sinking into the ground albeit, very slowly and almost definitely not fast enough to make a difference in level large enough to throw a balanced item off balance. Temperature/ humidity fluctuations cause objects to shrink or expand, but probably not enough to cause something to become off balance in a practical sense. Moral of the story, everything is always moving, even stationary objects to some degree. So it wasn't well balanced or it wouldn't have fallen over.",
"They ARE constantly falling, it's newton's law of action/reaction. At some point, whatever the ratio \"pushing back\" on the something to make it not fall had changed"
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m29s6c | Why did we ran out of IPv4 addresses but not out of phone numbers? | Technology | explainlikeimfive | {
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"Let’s do some maths, there are 4 numbers in an ipv4 address and each one can be 0-255, so 256^4 is about 4 billion A phone number has between 9 and 11 digits, downing on where you are that might change, so let’s pick 10. Each one can be 0-10 so 10^10 is 10 billion, already more than double, but there are country codes as well, so you basically have 10 billion numbers per country But even if we ran out of phone numbers, because of how the telephone system is made, you can just add a new digit in the front and it’ll still work, and this has been done in the past. However that doesn’t really work ipv4, as it’s only expecting those 4 bytes",
"We effectively *have* run out of phone numbers several times since they came out and we have changed the phone number system greatly to compensate. After there were too many phone lines for the operator to just connect you by knowing all the lines of the customers, they developed phone numbers. But they were strange things (to modern eyes) like CHelsea 4527. And if you wanted to call long distance, say from NYC to Chicago, you were first connected to the Chicago trunk, or main switchboard, who then connected you to RIver 2956 or whatever. Then later even that became too saturated (after WW2, it got so that many people could afford their own phone line as opposed to being on a party line, so numbers kind of exploded) so they introduced area codes, city prefixes, and 4-digit identifiers. Within the city, you didn’t have to use the area code but when dialing long distance, you did. In those days, long distance was not terribly far, FYI. I remember as a child it was long distance to call an address that was over the state line but since we lived right next to the state line (like I could walk to it without even becoming tired), that seemed ridiculous. Then once cell phones became popular, it became necessary to use the area code all the time, even from your land line. There are still some rural places, like my husband’s home town, that still don’t use the area code and locals there were perplexed with me for giving out my full phone number when they are used to only 7 digits. But eventually, they will have to use the full number. So, what’s next? I remember in the 90s, people saying that giving fax machines phone numbers would eat up all the available numbers and we’d be out of them but, of course, that never happened. I’m almost convinced that scammers who burn through phone numbers are the ones that are going to make us run out of our current 10-digit number system. You *can* reuse numbers somewhat but I believe there has to be a significant delay before they give the number back out. I suspect that within my lifetime, I’ll see at least one more major change with the phone number system. (This was about phone numbers in the U.S. I have no idea how phone numbers in the rest of the world were handed out and how they manage to increase the available field over time)",
"Well, for one there are only about 4.3 billion IPv4 addresses, and a lot of people have more than one device that needs an address. For phone numbers there a few things going on. 1. Phone numbers are a lot more complicated than that, their are international standards but in reality, each country can do their own thing. For example, the UK just...added other numbers to their phone numbers back in 1994. 2. There are more phone numbers, using the normal 11 digit codes you now get over 9 billion numbers (which again not everyone uses) 3. There are a lot fewer instances of a single person using a large number of addresses. Lots of people might have multiple devices but very few people have 6 different phone numbers. And if people do have multiple phone numbers oftentimes one of them is a work number. Which tends to use a single phone number and then an extension on top of that. For example, a company might have 900 employees each with their own extension used to call them. But they still only use a single phone number.",
"Phone numbers were handed out based on geographical area. And we know very accurately how many houses need phones in a given area for a long time. So we have been able to make sure that we use every possible phone number. IP addresses on the other hand was handed out based on network topology which followed organizational structures. But it is very hard to predict how many computers are going to be in each organization. So some organizations were given lots of addresses which they distributed among their departments and systems as they found best. But other organizations got very few addresses and had problems expanding into them. I have worked in organizations where even the guest wifi were set up with public addresses enough for huge conferences and I have worked at organizations that have had to cram hundreds of well paying customers into each address. The problem was made worse by the lack of foresight by the early adopters of IPv4. It was not supposed to be a worldwide network that everyone had access to. It was supposed to be a research network to test out various technology that could not be tested out on the old ARPANET in order to help design the up and coming OSI network that was supposed to be the next big thing. So the first organizations got ridiculously huge allocations so that they could easily segment it in a logical fashion."
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m29t9m | How is throat candy different to any other candy? | Chemistry | explainlikeimfive | {
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"It usually has an active ingredient in it to help with a sore throat. For example, Halls has menthol in it that will numb your throat and make you feel less pain for a while."
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m2c5e3 | Why do shots hurt afterwards? | When you get a shot, why do your muscles ache? Also how does rubbing and moving the muscle around help ease the pain? | Biology | explainlikeimfive | {
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"Fluid is being injected into the muscle fibers. This can cause a bit of damage to the muscle which your body interprets as pain. Rubbing the area moves the fluid around and helps the muscle fibers relax, alleviating the pain. Additionally, if you're getting a vaccine, the point of a vaccine is to stimulate the immune system. This will cause the area to flood with germ-fighting cells and fluid which can cause even more pain."
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m2c5rw | why do things get stuck up people’s bums, and why can’t they just push the object out? | Hurry. | Biology | explainlikeimfive | {
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"Nope nope nope. Getting stuff out of peoples rectums is part of my job. I’ve seen it all. The reason it gets stuck is it goes up above the anal sphincter muscle. What we use to control our bowel movements. Once it’s above, the sphincter clamps down. There’s an involuntary smooth muscle component that spasms. You can’t control it. Now it’s strapped. Usually trying to poop it out doesn’t work. Bc of the foreign object trauma the body won’t effectively relax the sphincter, which is what happens when we have a normal bowel movement. Also there is a vacuum effect in the rectum. There’s not a lot of air in there usually (believe it or not), and so the object can tend to migrate proximally (further up inside). So unless you act quickly and get a finger up in there and get it out, it’s stuck. Hence the ER visit and the call to one such as me. So if your putting stuff up inside, please please please make sure it has a handle or at least a string. Something which which you can pull it out. Stop with the cucumbers and the chorizo sausages. Something nicely lubricated with a handle. So I can actually get a full nights sleep. Thank you.",
"Imagine you're a driver of a pickup truck and you decide to drive up a narrow one-way street in the wrong direction to traffic flow. You go head-to-head against a car going the right way, and he's got a pile of cars behind him. You try to back out but since you're a terrible driver you don't reverse straight and get your pickup stuck slightly crooked. To straighten up you need to pull forward a little but the guy in front has his car right up against your bonnet. Now everyone is stuck. The one way street is your poop-tube. The cars are poop. You are a toy car truck you drove up your butthole.",
"In general, I wouldn't say that I poop on command. I go when my body gives me cues that it is ready. Contractions in the intestines naturally do the rest of the work. I can feel muscles in my buttox and can squeeze them tight, and release. If an object were past these muscles I can control on command, then I imagine I'd be SOL and hope the object passed with my next bowel movement. If there's an obstruction, I would seek medical advice. Choose anal toys with a small handle so you can pull it out in case of emergency. XD Good luck."
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m2dyu5 | the difference between Associative and Commutative Properties | I am back trying to math as an adult and feeling like a damn Five year old. Can anyone break this down simple for me to notice it looking at a math problem? & #x200B; Thanks ahead of time. | Mathematics | explainlikeimfive | {
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"Associative property is about how you group your terms. (2 + 6) + 8 = 2 + (6 + 8) Commutative property is about moving terms around. 2 + 6 + 8 = 8 + 2 + 6 Think associative is about who the numbers associate with (group with). Commutative is like commuting (moving around).",
"Suppose you want to make a cake. You want three layers: the crust on the bottom, the cheesecake in the middle, and the cherries on top. You have these three items separately. You have three operations you can do: (a) add crust to thing, (b) add cheesecake to thing, and (c) add cherries to thing. You can also combine them into operations like (bc) add cherries and then cheesecake to the thing (yes, in that order - I'm using the conventional order where the first action applied is on the right) or (ac) add cherries and then crust to thing. If you prefer, you can think of these composite operations as \"put the two things together, then add them to the cake as a single step\". Consider the operations c(ba) and (cb)a. The first operation is (add the crust and cheesecake in that order) and then (add the cherries). The second is (add the crust) and then (add the cheesecake and cherries in that order). Both of these make the same cake, and we say that c(ba) = (cb)a. This is the **associative** property: how you group the operations doesn't matter. On the other hand, the operation c(ba) (crust + cheesecake, then cherries) is very different from the operation (ba)c (cherries, then crust+cheesecake). These do *not* get you the same cake, and c(ba) does not equal (ba)c. How you order the operations does matter, so this operation is **not** commutative. -------- Addition is both commutative and associative. That is, (a+b)+c = a+(b+c) (you can group however you like when adding) and a+b = b+a (order doesn't matter). Subtraction is neither, if you consider it as an operation in its own right. For example, (8-3)-1 = 4, but 8-(3-1) = 6 (so it isn't associative - if it were, these would be equal) and 6-4 = 2 but 4-6 = -2 (so it isn't commutative).",
"Associative is for grouping, commutative is for moving. Associative: if I group numbers in addition or multiplication, it doesn't change the result. 1 + 2 + 3 is equal to (1 + 2) + 3 is equal to 1 + (2 + 3) 2 x 3 x 4 is equal to (2 x 3) x 4 is equal to 2 x (3 x 4) Commutative: If I move the numbers around, it doesn't change the result. 1 + 2 + 3 is equal to 3 + 2 + 1 2 x 3 x 4 is equal to 4 x 3 x 2"
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m2eega | I've seen "redo," "bootleg," and "remix" to describe a song being altered. Is there a technical difference between these terms? If so, what's the difference? | Other | explainlikeimfive | {
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"bootleg is an illegal recording, typically made in a live venue, of a song not formally pressed to a label. AFAIK, a remix is another established artist taking a song and putting their own slant on things. my only experience with this is EDM, and quite a few NIN songs. redo ... i suppose is the original recording artist deciding they hate their first press of the release and wants to do it differently.",
"Bootleg = somebody recorded a band play live, and this is the recording. Redo = artist who did the original does it again (Eric Clapton did a redo of Layla acoustic). Remix = Some takes the original work and modifies it enough to make the original song sound cemetery different by adding effects and other music.",
"I've never heard of \"redo\" but I can explain the other terms. A bootleg is usually when a song is recorded at a concert by one of the fans and then sold. The term comes from smuggling alcohol in the leg of a tall boot. A remix is when someone takes all of the musical elements of a song such as each separate instrument and the vocal track, and mixes them differently. This could mean changing the relative volumes of each track, altering the order of the elements in the song or even adding new elements."
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m2f0qu | What's the difference between rye whiskey and rye vodka? | My understanding with most liquors is they're distinguished by the main ingredient (molasses for rum, agave for tequila, etc). How does one take rye and end up with whiskey or vodka? | Other | explainlikeimfive | {
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"It isn’t just the main ingredient. It’s the process of making the liquor that determines it too. Vodka is made with pretty much any food/grain with sugar in it. They let that sugar ferment, turning into alcohol. And then they take the water and alcohol, and repeatedly distill it to leave some of the water behind leaving a high concentration of alcohol. Whiskey is made with a slightly different process. There’s still fermenting and distillation, but The starting grain goes through a malting process, which ferments it in a bit of a different way. The resulting liquor is then aged in an oak barrel, another thing that doesn’t happen to vodka, which influences the flavor/color of the whiskey.",
"Okay some of the other answers here are mostly correct, but not quite. Here's the deal: The primary differences are in the way each one is distilled, and then what happens to it after it has been distilled. In other words, it would be possible to take a fermented rye wash, and turn it in into either whiskey or vodka depending on what you did with it. Whiskey is nearly always distilled in what is called a pot still. A pot still can output alcohol concentrations high as around 80% ABV. Distilling through a pot still to 80% or lower enables some of the grain flavors to carry through to the final product. In contrast, Vodka is supposed to be a neutral spirit, so they try to eliminate as many of the grain flavors as possible. One way to do this is by distilling it to a very high ABV (around 95%), often multiple times. Most Vodka distillers use a reflux still instead of a pot still, which enables them to achieve this higher ABV. (Some brands however, like Titos, actually use a pot still, but distill it a bunch of times.) Another way to eliminate flavor is by filtering the spirit multiple times. Another huge difference between the two spirits is that Whiskey is aged in oak barrels, usually for multiple years. This gives it its characteristic brown color, as well as the oak-y flavor, the vanilla, and other more complex flavors. Theoretically, you could put vodka into an oak barrel, age it, and you might get something that tastes sort of like whiskey. You would still be missing those grain flavors that you get in real whiskies though, and it would probably have a \"flat\" taste, or one that lacks complexity."
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m2f3nd | How do we track Mars rovers if there is no global positioning system (GPS) on Mars? | Technology | explainlikeimfive | {
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"We compare the images from satelites surrounding Mars using things like HiRISE if you are interested here is a [link]( URL_0 )"
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m2ficz | Is there a point in space from which no stars are visible? | If you were hurdling through space, is it possible that you’d eventually come across a point from which you couldn’t see any stars? Are there too many stars in the (known) universe or does starlight travel too far for that to be possible? If that point does exist and you made it there, would it just be pitch darkness (as if your eyes were closed)? So many questions about space tonight!! | Other | explainlikeimfive | {
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"Probably. Few people realize this, but the overwhelming majority of the stars you see are with the naked eye are just our closest neighbors in the Milky Way Galaxy. With the naked eye, you can see a few of our neighboring galaxies, Andromeda probably, the Magellanic Clouds if you have good eyes. But other than that? Probably not. And there are places in the unviverse with very few galaxies about. Astronomers call them [Voids]( URL_0 ) They may be places inside them too far from another galaxy to see anything.",
"No. Beyond a certain scale - about a billion light years, give or take - the Universe appears basically the same from every vantage point, so the Universe to other observers would look much the same as it does to us. We can verify this directly out to a decent distance, and it's an assumption of cosmology that it's true even further out than that. Now, there are regions where there are very few stars or galaxies, so there are places that there aren't stars close enough to be visible to the human naked eye. But they're still there, just far away and dim.",
"Yes but it is more a point in time rather than a point in space. If you head out to intergalactic space and just wait where you are long enough eventually all the stars in the universe will be to far away to see due to expansion. This would take a very long time. But there is no point in space(in the observable universe anyway) that is currently far enough away to not see stars."
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m2frqt | When your joints crack, what exactly is the pop sound you hear? Why do the pops sound different sometimes? | Biology | explainlikeimfive | {
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"All joints have a capsule. The capsule contains the lubricant: synovial fluid. When the joint moves into end ranges, this allows bubbles to form within the capsule. The forceful pressure of the joint releases those gases resulting in a popping sound."
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m2g0c1 | How did our measurements of temperature(Celcius, Fahrenheit, and Kelvin) come about? | Earth Science | explainlikeimfive | {
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"Fahrenheit's just weird, so we'll get to him later. Celcius makes sense. People saw that shit could get hotter or colder, and that this was seemingly limitless, so they just picked a point to call zero. For convenience, they chose the temperature that water freezes to be zero and the temperature that water boils at to be 100. That's easy enough, eh? Only later, we found out that there actually *is* a 'coldest temperature' - this temperature turns out to be -273C. *Absolute zero*. It turns out that this temperature is actually pretty important for some physics/chemistry, and so a new scale was invented. Kelvin. They used the same degrees as celcius for convenience, but shifted everything over so that 0 kelvin is absolute zero, so you will never see something at negative degrees kelvin. Fahrenheit is like celcius, but the temperatures chosen were a lot more random. A kelvin-analogue for fahrenheit was made, but because fahrenheit sucks for scientific stuff anyways it was never used much. I forget its name. ------------ Gonna add more in an edit in a bit When measuring things at room temperature, kelvin is overkill, since all of your temperatures will be in the hundreds. As such, celcius and fahrenheit are still regularly used for normal activities. As for other measuring systems, that's its own question."
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m2g4o5 | Why is chickenpox more harmful when older? | Iirc chickenpox becomes even more dangerous after 11 or so, and can have life-altering effects. Is there a change around this time that causes this? | Biology | explainlikeimfive | {
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"The correct answer is that we are not really sure. Immune systems are different in children and adults, children rely more on large phagocytes cells and adults use more antibodies. So different responses might be responsible for the varying rate and severity of complications. Another theory is that the virus itself is not hitting its most opportune window anymore and thus increased symptoms are a sign that things aren't going right for the virus. Viruses don't benefit from killing their hosts in most cases. A virus that is specialized to propagate through young children might not be calibrated to work correctly through an adult body. Polio is a good example here. Polio was a much less severe illness in very young children but was also a common affliction. Increases in water filtration standards caused a drop in polio cases that also created a time delay in when children were exposed to it. Thus a tragic rash of cases where polio affected older children with much more severe symptoms and life long complications. I haven't seen any conclusive studies on this myself though. So, as far as I know it's still speculation.",
"I had chicken pox in my early 30s. My kids got it and went through it pretty easily. They ended up giving it to me. Total misery for 3 weeks, plus some permanent scarring. I still remember once trying to drink orange juice not realizing I had pox down my throat too. Funny now but painful then."
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m2g6u0 | Why do stock markets have breakers to halt the stock price in its tracks? | Why not just let it rise and fall at the public's desire? | Economics | explainlikeimfive | {
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"There used to be no circuit breakers. Crashes were much more severe. Breaks allow time to cool off and absorb what is going on.",
"People trade emotionally (“panic selling”). Previous crashes taught us that if you temporarily halt something going off the rails you can blunt the impact of panic selling.",
"One people trade on emotion and stopping for 10-15 minutes let's people stop, think and not panic or make a plan. Also a bigger reason is most trading us done by computers and algorithms. Sometimes these run away and create a feedback loop when they all start selling and don't stop. Stopping trading also will give people time to adjust these algo traders."
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m2gf5w | what causes a charlie horse and what makes it hurt so bad | was just laying in bed and got an insanely bad cramp in my calf. made me wonder this | Biology | explainlikeimfive | {
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"Charlie horses, sometimes called a frog in your leg, are usually caused by the muscle seizing up due to mixed signals their getting. Dehydration will cause your nerves to have a harder time stopping their \"fire\", this is due to them working with salts to send electrical signals throughout your body. Water dilutes the salts to make them move around easily (it's more complex, but that's the basic gist). When you're dehydrated they have a harder time moving and can get \"stuck\" in either state, on or off. (Not literally the whole nerve, but the parts that interface with muscles) So, when you get Charlie horse-d because someone hit you or you stood up too quickly, it's because your brain is telling your muscle to fire, but they never receive the signal to stop. The reason it hurts so damn much is because human muscles are not really designed to be clenched at all times and they dont have an easy way to get rid of their lactic acid (along with other byproducts), which causes the burning sensation. Making sure you get enough water and have salts in you is a good way to prevent them, but the only way to really get rid of them faster is to massage them into submission or stretch them out, as stretching can help move the nerves around and subsequently stop the firing."
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m2gmpz | Whats the difference between a psychiatrist, psychologist, and a therapist? | Other | explainlikeimfive | {
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"Psychiatrist: a doctor, who went through med school, who prescribes psychiatric meds. Occasionally also provides therapy. Psychologist: person with doctorate level education (PhD) but not medical doctor. Can do a range of jobs: be a therapist, do psych testing, consult for many fields, etc. In USA- school psychologists just need Masters degree, but any other psychologist is PhD. Therapist: person who delivers therapy, usually referring to talk therapy. Can have a range of qualifications, like: usually a masters degree (at minimum) may be LCSW/LICSW, LMHC, LMFT, psychologist, etc. Generally does not prescribe meds unless they are also a nurse practitioner or psychiatrist. Note: there are other therapists, like occupational/speech/behavior but you usually hear the word in front of therapist in that case.",
"A psychiatrist is a medical doctor (M.D. or D.O.) who has attended medical school and completed a residency in psychiatry. They take a medical approach to therapy and are able to prescribe medication. Their focus is usually on the biological processes involved in mental disorders. Psychiatrists may or may not provide talk therapy in addition to treating mental illness through medication. A psychologist has earned a doctorate in the field of psychology (Ph.D., Psy.D., or Ed.D.). There are many branches of psychology, including clinical, developmental, experimental, quantitative, industrial/organizational, school, forensic, and so on. Not all of these branches involve therapy at all. For the branches that do involve therapy (such as counseling psychology), their focus is usually on the thoughts, emotions, and and behaviors of the client that can be treated through some form of talk therapy. Most psychologists are not able to prescribe medication without additional licensure. \"Therapist\" is a more generic term that can apply to a large number of fields. Psychiatrists and psychologists can both be therapists, as can social workers. There are also various certifications that a person can get without a doctorate to allow them to provide specific types of therapy, such as LPC, LPA, LMFT, or LCSW. Generally, if a person calls themselves a therapist as opposed to a psychiatrist or psychologist, it is because they have one of these licenses rather than a medical degree or doctorate. The type of therapy they provide will depend on their licensure. EDIT: I want to point out that although most psychologists and licensed therapists cannot prescribe medication, many of them do have knowledge and experience on how medication can be used with their treatments. They can suggest medications to you that can then be prescribed by your doctor. Because of this, psychiatrists are not the only option if your mental illness requires medication, but they usually are the most direct option."
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m2h8c2 | Why do people hear music differently? | Other | explainlikeimfive | {
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"Listening to music is influenced both internally and externally. Some people hear certain frequency bands more easily than others, meaning certain sounds might be more/less salient to an individual. However, there is a large social component in how you model listening music from others - learning how to pick out details in composition and writing (much like how artists have influenced in identifying and creating poems or paintings). Both factors intertwine from a very young age, and can look different in a variety of people 10-20-30 years down the road Edit: I also find out easier to identify elements of music that I practice if I make my own, because I know what to look for since I know how it sounds"
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m2h9t3 | How do batteries release and store energy? | Chemistry | explainlikeimfive | {
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"If you have two different metals, one of which wants electrons more than the other, you can get one of them to donate its electrons to the other. Then add in a \"salt bridge\" that keeps negative charge from simply piling up on one of the metals and stopping the flow of electricity by repelling the incoming electrons. And that's basically all a \"galvanic cell\" is. By connecting the two metals with a wire, you provide a path for the electrons to flow between them, i.e., create a current. The trick is to put something in the middle of that wire, like a motor or a light, so they can do some work for you while they plod along to the other metal. Batteries then consist of multiple galvanic cells stacked on top of each other to collectively output more current."
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m2hpy4 | Why invest in a gold company instead of simply gold? Why invest in a (passive) asset manager instead of simply the overall market? | Why invest in the producer instead of commodity? Is the answer just operating leverage? | Economics | explainlikeimfive | {
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"Because the producer has a greater scope for fluctuation, meaning that an investment has the opportunity to pay off faster should the markets favour you, since the stock of companies tends to fluctuate more rapidly and gold in particular is famed for being a very stable investment",
"They're very different really. When you invest in a mining company, the stock price isn't simply tied to the price of gold. The demand for gold could be high while the mines of the company you invested in are depleted. Or their equipment is outdated. Or their workers are on strike. Or gold demand could be low but your company is very cost effective in their operations.",
"Why invest in a passive manager... scale and transaction costs... trying to invest a small amount of money to replicate an index would require many small transactions each coming at a cost. Across an index with hundreds of these transactions costs would add up and make buying smaller components cost prohibitive. Or you just pay someone 0.10% and they do all of this for you. If you have millions to invest and want to spend the time to do it then sure it may be cheaper to do it yourself."
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m2id5a | Three 1/3 is equal to 1, but three 0.33 is 0.99. What exactly happens to 0.01? | Mathematics | explainlikeimfive | {
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"An infinite string of 0.9999's is exactly equal to 1. You have just proven it in one of the ways that are shown to students learning about this stuff. Keep thinking that way - it's awesome!",
"1/3 third is not equal to 0.33. It’s equal to 0.3333333... an infinitely long number of threes. Now if you multiply by three you get 0.999999999999... an infinitely long number of nines. So now the question is not what happens to the 0.01, but what happens to the . That’s not even a real way of writing a number because you can’t have an infinite number of zeros and then a one at the end. The zeros go on forever; there is no place after that for the one. But if it was a way to write that number, it would be the indistinguishable from zero: it would behave exactly the same as zero in all math operations, so we can say that it actually is equal to zero. Another way of saying this is that 0.99999.... and 1 are two different ways of writing the same number, just like 0.3333333... and 1/3 are two different ways of writing the same number.",
"An infinite string of .9999999999999 is equal to 1 .99 flat is not. The infinite part made it cross the line. One exercise to see how an infinite subdivision leads to a whole number is to imagine if it didn’t. Say you wanted to walk from point a to point b. However in order to get to point b, you’ll have to walk a 10th of the way to point B, but before that, you’ll have to walk 100th of the way to point B, and before that 1000th of the way, 10,000ths, 100,000th. As we agreed for the sake of argument, that infinite subdivision doesn’t add up to a whole number, you must conclude that you cannot walk anywhere, since you need to cross an infinite subdivision of the whole journey. A Greek guy name Zeno came up with this example, but never figured out that the solution was that infinite subdivision can equal a whole number. Now just think of the subdivisions as the percentage of the journey you have left. Each subdivision is like slapping down another 9 at the end. when you slap down an infinite number of 9s you have the whole.",
"What you have discovered is the fact that the decimal system (numbers in the form 0.333 for example) is unable to show all numbers. 1/3 is actually equal to 0.33 \"and a bit more\". To make it easier to read and calculate with, we leave out the extra bit since even without it we are close enough. When you add together multiple numbers where a little bit has been omitted however, the many small bits become large enough together to matter. This is why when calculating fractions (1/3 form of numbers), you should only ever round and convert to decimal at the end of the calculation, not in the middle of it. This minimizes the error created by missing (or extra) small bits. As some extra info, the property you describe is actually a very big problem within programming, since a computer tends to want to store the results of division as a decimal number. Thus, if you set up multiple divisions after each other, you will end up with significant rounding errors."
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m2j1dx | Why are some grapes in the supermarket rock-hard and crisp, and others are more spongy and soft? Is it simply because the spongy ones are over-ripe? Or is it something related to how/where they were grown and stored along the way? | Other | explainlikeimfive | {
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"Not an expert on these things, but I think it has to do with water content. I have a container made for storing grapes in the fridge. You're supposed to add a little water in the bottom of it to keep the air moist, and the grapes stay firm longer. But if I don't add water, the grapes dry out faster and they get spongy. I bet if you chop off the end of the vine and stick it in water, it would soak up the water and the grapes would get more firm. I've done this with an aging head of lettuce and it got more crisp in about 30 minutes."
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m2jnyy | . Why does 70 degree (Fahrenheit) air feel warm but a 70 degree shower feel cool? | Why does 70-80 degree feel warm, but 70-80 degree water feel cool? | Other | explainlikeimfive | {
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"Water is way better at transferring heat away than air. We don’t really sense temperature, we sense differences, and rate of transfer. Picture two objects for instance, one metal and the other wooden. The metal object will feel colder, even if both have been sitting out at the same temperature, because it transfers heat away from your body faster.",
"Air is a very poor thermal conductor. Heat doesn't easily move from the air into your body or vice versa. Water on the other hand is very good at conducting heat. So water that is substantially colder than your body temperature will pull heat from your body. This transfer of body warmth to an object is the sensation we feel as \"cold\". As a side note, sweat takes advantage of this because air is so poor at conducting heat but water will pull excess heat from your body and evaporate more easily to cool you down after exertion. Without sweat or other means of cooling humans would overheat from moderate exertion.",
"Water is a better conductor than air. Basically if air can absorb one heat unit in one time unit, then water can absorb two heat units. That’s not the actual numbers, but you get the idea. “Cold” is just the absence of heat, so the water, conducting away heat faster, feels colder."
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m2jpoa | Why were IPV4 addresses so limited, when MAC addresses were made so much larger? | Technology | explainlikeimfive | {
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"Because MAC addresses have 48 bits while IPv4 addresses have only 32 bits. This means that for every IPv4 address there are potentially 2^16 MAC addresses. Why? Because they were defined by two different organizations. The people who came up with IP thought that 32 bits were enough (and to be fair, at the time they were) and the people who came up with MAC addresses thought they needed 48 bits."
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m2kvr8 | What is a human’s natural sleep position supposed to be? | Biology | explainlikeimfive | {
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"It seems like the most common is the fetal position. It's good for heat retention and it allows you to use your arm as a pillow. Your hip is the real problem there, but considering the oldest known human matresses(piles of leaves resembling nests more than a proper mattress) are some 70,000 year old. This may not have been an issue. In a pinch you can scrape a small hollow in the ground for your hip to sit in and be much more comfortable. But \"supposed to\" rarely fit the natural world. People probably slept in whatever was most comfortable. For example you might be a fetal sleeper most nights but on a super hot and humid night you might find yourself on your back splayed out to be as cool as you can.",
"I always have ultra vivid dreams/nightmares if I sleep on my back. Sleeping on my side doesn't have this effect. Is there any science behind this?",
"Contrary to popular myth, the natural sleep position for a human depends on each human. Specifically, which ever position that comfortably lets him/her fall asleep is natural. While sleeping on some positions are disadvantages it might be better to check with a doctor if you think something is wrong.",
"Follow up: Is there any reason that laying ony back to sleep causes me to feel sad? (More sad than normal for me anyway) I generally sleep in a sort of recovery position but would like to sleep on my back occasionally so I'm not 'hunching' my shoulders at night.",
"We don't have one. Our spines are still halfway between bipedalism and nesting in tree canopies Thanks to our fantastically large complex brains we've had 20,000 years of being able to jury rig a decent nest/bed to help conform and support our jank-ass skeleton and get a decent nights sleep in. But that also means that there isn't much selection pressure to produce a genetically well sleeping person. The result is a population of 7 billion shaved apes that all have unique best practices for sleeping."
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m2lt4x | If the exoplanet HD 100-546 is larger than some stars, how come it hasn’t collapsed into a low-mass star? | Physics | explainlikeimfive | {
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"We have just started to research the HD 100546 star system. It is a fairly young system and still have its acreation disk which planets form from. So it is very hard to see things in it. Adding to this there are not may star systems of this type so we do not know these very well. Whe do have some indications of one planet or maybe even two planets in the star system. And one of these is large enough that it could be a brown dwarf but it could also be a regular planet. There is some overlap in masses between brown dwarfs and gas giants because they can have different densities, composition, temperature, core material, etc. which does affect its ability to burn deuterium or not. We do not know if HD 100546 b does burn deuterium which would make it into a brown dwarf but from what we can tell now it does not look like this process have started making it a gas giant.",
"HD 100-548 is far from being large enough in terms of mass to turn into a star. It is not even big enough to be counted as a 'Brown Dwarf' which are basically larger versions of HD 100-546b. HD 100-546b maybe larger in terms of volume than say a red dwarf (which is a star) but it has no way close to enough mass to turn the fusion on.",
"On Earth, if an object gains more material, it gets bigger. But with GAS planets and stars, if the planet gets more gas material, gravity gets stronger, so it pulls the gas more, so the planet or star gets slightly smaller. Basically, mass shrinks the planet, and creates more pressures and heat in the core, until the pressure and temperature are sufficient for nuclear reactions. At which point the heat from the nuclear may create extra pressures and inflate the star again. Anyway, big (volume) does not necessarily mean heavy (mass), so you CAN have a visually big planet that is lightweight, by gas giant standards, and not have enough mass to have nuclear reactions and be a star.",
"These small stars like white dwarfs are extremely dense (like thousands and millions of times more dense than “normal matter” with which we are familiar through our senses and which makes up planets). They have already burned up their thermonuclear fuel and collapsed in on their own insides catastrophically, having no energy to support their outside layers. Gas giants as planets don’t have enough mass for a thermonuclear reaction to start in the first place.",
"This is a gross oversimplification, but I'm only patching this together after a couple minutes of research. That's because it *isn't* more massive than some stars. It's much less. I saw an estimate somewhere that this planet has, give or take, around the mass of 20 Jupiters. This is, and I'm being very optimistic here, barely enough to form an extremely \"cold\" (still pretty hot compared to a summer day) brown dwarf. It takes hundreds, if not thousands, of Jupiter masses to form even the smallest Red Dwarf star. Further, depending on who you ask, brown dwarves aren't stars at all: they're just huge gas giants with **some** stellar properties. Again, this is a MASSIVE oversimplification, but hope that clears something up."
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m2moio | Why do you see cigarette filter packets, still containing usuable filters on the floor of streets and paths outside but never any unused tobacco? | I didn't think you could even buy them alone, do people just get too many filters in their roll-your-own ones or something? Edit: Forgot to mention lack of rolling papers on the ground too | Other | explainlikeimfive | {
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"You buy filters separately, they usually come in a pack of 100+, super cheap as well so people are wasteful with them",
"As someone who smoked rollies, I assure you that it's easy to loose a filter or two when you roll or when you take them out. The packaging of many brands is really bad and can often open in your pocket aswell. Like, I joke a lot about smokers finding lighters on a regular basis in their pockets, but I think I found more lost filters than lighters in my whole smoker's life."
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m2n6i7 | What is the most simple device that can be considered to have "software"? Does it have to be digital? | Does a mechanical timer have software? What about a wooden marble adding machine? An analog watch? A musical box? A digital watch? A hand-held calculator? Where does software begin? | Technology | explainlikeimfive | {
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"Here is an analog [programmable device]( URL_0 ) that ha been around for a long time. The software was similar to the punchcards we used to use with mainframe computers. I wouldn't say that the device is \"simple,\" except in comparison to digital devices that are far more complex.",
"In general, software is a list of instructions for a processor to execute. So yes, it has to be a digital sistem and something that isn't \"hard-wired\" to do a certian thing (for example a simple logic gate). Software runs on systems that don't do anything by themselves and need to be additionally \"told\" what to do. This doesn't have to be in the form of code, it can be as simple as physically flipping a series of logic switches. Handheld calculators are generally hardwired for a specific task (except the fancier ones) so those don't have any software. But, \"software\" is a made up term and it doesn't really have any real physical counterpart to define it, so the definition can get a bit fuzzy. Edit: You could argue that by putting an equation into the calculator you're \"programming\" it or putting in software that it runs. That's where the definition really gets blurred.",
"You could say that the piano roll on the old player pianos or the cards on a jacquard loom are stored instructions, which would make them something like software. But neither is a simple device, and the software can't change the fundamental behavior of these devices like software in a modern computer can.",
"Software is a way to give \"instructions\" to a device to make it do what you want it to do. It is \"soft\" in the sense that it can be changed to make it do things in a different way. When I was a pre-teen, we had a \"digital\" clock, but it was digital only in that it moved black slats over the lights to change the numbers. (I was fascinated by this device, BTW.) In this case, it was the cams that pushed or pulled the slats back and forth that made the numbers. It was a mechanical device (some small electrically-powered timer) that would shift the numbers forward by moving a shaft each minute. I would consider this crude software; if the cams were shaped differently, you'd get different number, or arrangements that didn't make any sense. When most people talk about software, they mean instructions that run on a digital device that can store and retrieve data, can do math, and can make decisions based on various inputs (including existing data). But this is not the only type of programmability. For example, early automation for weaving cloth would use punched cards with holes that would tell it when to insert or relax a given thread, allowing patterns to be built up by weaving. This is certainly software, and someone had to encode (program) the patterns, but it was not really a digital device except for the push/relax of a given thread. So I would conclude that \"software\" is a fuzzy term that only relates to programmability that can be changed. These \"programs\" can be used in mechanical devices... in fact, all devices become mechanical at some point because the program has to reside in a physical device. The conversion from mechanical to digital is usually done with electricity (e.g., your mechanical keyboard converts the physical push into a signal), and it gets back to physical at some other point (the electrical signal lights up a display, or it actuates a robotic arm in a automobile factory). Whether there is digital processing in between is not always required."
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m2ne5d | How does tennis racket theorem (dzhanibekov effect) work? | Physics | explainlikeimfive | {
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"There are two important conservation laws which describe the movement of a rigid free-falling, spinning object. One is the conservation of angular momentum, and one is the conservation of kinetic energy. The key to all this is to understand that for every axis an object can spin around with (for instance) 1J of energy, there is a certain ratio of kinetic energy to angular momentum associated with that spin. In order for a spinning object to tilt, and both conservation laws to be obeyed, its new axis of spin will have to allow the same angular momentum *and* the same kinetic energy as it had before. When an object is spinning around its minor axis - like a spinning plate or a frisbee - then the object's kinetic energy is maximized, relative to its angular momentum. This is because quite a lot of the object's mass is located far away from its axis of rotation. As far, in fact, as it can be. This is why industrial flywheels are designed as they are, with a big heavy rim, because this means they can store a lot of kinetic energy for a given RPM. When an object is spinning around its major axis - like a twirling figure skater - then its kinetic energy is minimized relative to its angular momentum. This is the opposite of the flywheel situation. By making themselves tall and narrow, figure skaters maximize the RPM they can spin for a given amount of kinetic energy. In both these extreme cases, the spinning is stable because in order for the axis to tilt, the spinning object would either have to gain angular momentum from nowhere or lose kinetic energy to nowhere, or else vice versa. And if the object is under no external forces, then neither one can happen. These are the only two spins with that special property. Every other axis of spin, has some neighbouring axes which will also yield the same ratio. But the major and minor axes don't, because their ratios are the highest and lowest possible for that object."
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m2ojfb | Why is a 3 x 3 Picture Rubiks cube more difficult than a standard 3 x 3 Rubiks cube? | Surely Rubiks cubes can only have one solution? Or have I missed something. Is the algorithm for a picture cube much more complicated than a standard 3 x 3? Further context: I've had the same picture cube for about 10 years and never solved it. | Mathematics | explainlikeimfive | {
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"Two things: 1. The center square has to be oriented correctly in a picture cube and if you've only ever learned on a normal cube, figuring out how to change the orientation of the center square is an added challenge. 2. Depending on the pictures it may not be immediately clear in a mixed-up cube where each square belongs.",
"I have not solved a picture cube so I am not able to say much about the complexity. But I think it is possible to rotate the center of the face of a cube which does not make any difference for a normal cube but does so for a picture cube. However the biggest issue I can think of is that with a normal cube it is very easy to see where each piece goes and which sides are opposite of each other. This makes it much easier to solve a cube as you can just instantly look at a piec and figure out how to put in the correct place without having to look at any of the other pieces. However depending on the picture printed on the cube it might be very hard to know where each piece goes. It would be like solving a jigsaw puzzle and a rubics cube at once.",
"In a classic rubiks cube, you don't care about the orientation of individual square faces because they're colors. With a picture cube, now suddenly the orientation of each square face matters. You introduce more algorithms into the solve",
"it is only marginally difficult than a normal 3x3,this is because in a normal 3x3, the orientation of the center piece on each face does not matter you can visualize this by drawing a letter or arrow on each center piece, in the finished solution of a normal 3x3, it doesnt matter which direction the arrow points in, but in a picture cube, the orientation of that center piece is necessary for the picture on each side to make sense. & #x200B; orienting the center pieces is a little extra work, but not a lot different from the normal method of solving a 3x3, although it will probably take your mind a little more time to match the correct pieces together because they are partial pictures on each piece instead of a fixed colour"
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m2oo74 | why when I’m standing on a moving train and I jump, the train doesn’t move around me? | Physics | explainlikeimfive | {
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"The train gives you its forward motion after you climb aboard and it starts moving. Everything in the train, you, other people, the luggage, the air, everything is moving forward at the same speed as the train. Things in motion tend to stay in motion unless there's some force acting upon them. Friction, or actually being pushed, etc. So if you were to jump straight up, and at that moment the train slammed the brakes for some reason, the train would slow down abruptly, but you would still have the same motion as before, because while you're airborne (from the jump) only the force of gravity affects you, and gravity pulls straight down, not sideways. So you would see the train suddenly stop, and a camera bolted to the train would record you suddenly moving forward. This is why they have seatbelts in cars. You're going at the same speed as the car, but if the car hits something, IT would suddenly stop, but you'd be still [going forward at the same speed]( URL_0 ), and basically hit the front of the cabin and/or with possibly enough force to be thrown through the window.",
"You push upwards when jumping, so you do not change your horizontal speed when you jump. It remains the same as the speed of train. If, however, the train accelerated or slowed down exactly at the moment you jump, then it will move around you, forwards or backwards.",
"Velocity isn't an absolute thing, you're always moving relative to something else. Right now you assume you're standing still, but in reality you're only standing still relative to the earth. You're actually moving at thousands of kilometers per hour relative to our solar system. When you're in a train it's the same story. You're standing still relative to the train, but you're moving relative to the ground. A jump won't affect your movement in the horizontal direction, according to the train you're still standing still (albeit 20cm off the ground) and according to the ground you're still moving. In order to start moving (relative to the train) you need to add some force in that direction, for example by walking or running. Some confusion might come into play because of air resistance. If you're watching a movie where some guy is standing on top of the train, jumps and flies off like the train is \"moving away\" below him, he's actually being pushed off by the force of air slamming into him. If you're inside a train this doesn't apply.",
"Answer. Because you are moving as fast as the train. If you were standing on the top of the train and jumped your forward motion would stop because you'd be hitting a wall of air that isn't moving. When you're inside the train, the air, you and the train are all moving at the same speed.",
"Essentially because objects will always move in a straight line at a constant speed. Unless you do something to change it: In you scenario, you are moving at the same speed as the train. So unless you do something about it, you will keep moving at the same speed as the train."
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m2osgd | Why does oil in a frying pan, sometimes pop while it heats up ? | I am curious as to what causes this issue where sometimes my oil seems to explode upwards and splash all over my kitchen. It never seems to happen when the Oil is fresh. It stops happening once the Oil gets hot enough. But why ?! | Chemistry | explainlikeimfive | {
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"It’s bubbles of boiling water forcing its way out of the oil. The oil in the bottle/can accumulates some moisture from the air after it has been opened. Also the pan might have had some water on it when you started cooking. It stops happening once all the water has boiled away.",
"Pro tip from someone who went to culinary school: Pre-heat the pan to evaporate any unseen moisture on the surface before adding oil.",
"You need to dry your pan better before adding oil. What you're seeing is small bits of water flash-boiling beneath the oil (remember, oil floats on water), causing small explosions that are spattering oil around your kitchen. This is a great way to make your kitchen an oily mess and to end up with some real unpleasant burns. Wipe your pan with a towel, then leave it over the heat for a bit to let any remaining dampness boil off before adding oil.",
"All these responses is why you do NOT use water to put out a grease fire. Imagine the popping you are seeing with a little surface water, and multiply that by a cup of water. Hot flaming oil goes everywhere.",
"It’s water. There’s a test for the presence of water in lubricating oil called the crackle test “The crackle test is a standard laboratory test to detect the presence of water in lubricating oil. A drop of oil is placed on a hotplate that has been heated to approximately 400° F. The sample then bubbles, spits, crackles or pops when moisture is present.”"
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m2ou22 | Why does Rendering a Movie takes so long but a video game can render within milliseconds? | Technology | explainlikeimfive | {
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"Video game scenes are much, much less complicated than animated film scenes, in terms of detail, depth, resolution, lighting etc."
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m2qjw1 | how can radiation penetrate eveything but still leaves no visible holes | Physics | explainlikeimfive | {
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"Imagine a volleyball net. There are three main types of radiation: alpha, which would be a volleyball. Then beta, which would be a tennis ball. And gamma, which would be a grain of salt (but not really since it is an electromagnetic wave). Scaling only for an example. Now throw these at the net and see what happens. The net is the matter around us. It can block some radiation, but not all. Edit: can't believe I am getting this recognition for such a simple explanation, thank you!",
"The holes are already there, they're just too small for you normally Objects are uniform solid things, most of the volume is just empty space between the atoms, but because its electrons and your electrons push back at each other from a distance it seems solid to you Objects are more like a dense forest. If you try to drive a big car through it you'll just get stuck because there isn't enough space between the trees, but you can walk through it and if you were the size of a mouse then there'd be tons of room between the trees to sneak through Radiation is little high energy particles like electrons or photons like gamma rays that are soooo tiny that they can easily squeeze through the space between the cores of atoms and get out the other side. If you want to stop them then you need to put enough big atoms packed closely together in its path (like in a dense element like lead) so that the particle will almost certainly hit something before it can pop out the other side. Even when it does hit something it generally just gets absorbed and turned into a bit of heat in the material rather than blowing a hole through it like a bullet might",
"It's important to note that *not all* radiation can penetrate everything. Alpha radiation can only travel a few feet and is stopped by paper. Radio waves are oftentimes blocked/scrambled by metallic frames. Otherwise, it's similar to how a pebble can get dropped in a pool of water and sink to the bottom without leaving any holes. It has enough mass and energy to push through the water. In the case of radioactive particles traveling \"through matter\", it's really traveling through the gaps and space in the individual atoms and molecules that make up the objects you see.",
"The short answer is that everything around us is already full of holes. The holes are frequently just too small to see or for most things to pass through, so we treat things like they are fully “solid” barriers even though they are not. Many forms of radiation operate on a level where they are small enough to pass through these holes that most things can’t.",
"Radiation is just light (for simplicity's sake). Take visible light, for example. That's a kind of light that passes through air pretty well, walls no so much. The wifi in your router is another kind of light, and it can pass through walls pretty easily. Infrared light doesn't leave holes, but it DOES interact by making a lot of things hot. Radiation interacts with things in a similar way. (well, not exactly, but this is ELI5)",
"You know how light goes through glass, water and other transparent things? Light is a type of radiation. And if you could see radiation, things that it passed through would look transparent.",
"Imagine the atoms that make up the stuff around us as trees seen from above, with the trunk being the nucleus and the interconnected leaves and branches being the electron clouds and bonds that hold the atoms together much like trees growing together in a forest. Now if you tried to carry a whole bunch of already interlocked trees through this forest, you can appreciate that you're going to have to cut down some of the trees in your way or else the branches are going to snag together. This is the same as a bullet or other big solid object blasting through a wall; their electron clouds really don't like to overlap and like to resist this, so passing through the wall involves pushing all the intervening atoms out of the way, which creates a hole. Very penetrating radiation particles are like small birds that can just fly between the branches; to them the branches might as well not be there, and so they can pass through the forest with relative ease without moving any atoms out of the way. I'd like to note that not all radiation particles are like this, some are large enough to act like individual trees, and these do often interact with the \"forest\" of atoms much more. That being said, they still have much less mass than say a bullet, so they're not going to be moving many atoms aside. However, they CAN move aside single atoms very efficiently, which can be a very bad thing when those atoms are parts of your DNA. That's why radiation can be so good at screwing up your DNA and giving you cancer.",
"Do you mean radiation as in the form of the whole spectrum, i.e. microwaves, ultraviolet, infrared, x-rays, radio waves, etc?",
"The same way that light passes through glass. Some radiation is good at getting through different things, and/or some things are transparent to different kinds of radiation. For example, the normal frequency for Wifi (2.4ghz), is pretty good at getting through most things. It gets blocked by metal and water, mostly. If you imagine a strong light bulb sitting where your router is, and that everything in your home that isn't water and metal were glass, you would have a pretty good idea of where your wifi works well. Wherever a shadow is cast, it will not have the strongest signal. To very powerful radiation, everything is glass.",
"The same way light goes through windows. The space between atoms is sufficiently wide to allow light particles to go trough. Photons are stopped when they are absorbed or reflected. To do so, what they hit needs to either have room to absorb the energy or it can't be absorbed and the gap between atoms is smaller than the frequency (wavelength) at which the light is. Radiation has a very small wavelength, while normal surface have larger wavelength between their atoms. Which means radiation goes trough. It it gets absorbed, it causes a lot of damage because its a lot more energy than what the atom can absorb and remain stable.",
"I'll talk about Alpha, Beta and Gamma radiation. Alpha and Beta radiation can be stopped, alpha by a sheet of paper and Beta by a layer of aluminum. Because it's basically particles travelling at high-speed, so it can be stopped with matter. But Gamma is different, like x-ray it's light. And just like visible light can travel throught glass, so does gamma/X-ray can travel throught a wall as if there's nothing. Unless it's a material with properties capable of absorbing Gamma/X-ray, it won't stop. This is why lead is used. Even so, gamma can go throught lead. My analogy for that is that lead is like a really opaque glass, with enough lead you can stop the radiation, but use too little and it won't be able to stop all of it.",
"I see several good answers all of which actual do not answer the last part of your question, namely that of holes. So as others have pointed out \"penetrate\" can mean different things. If I throw a tennis ball at a volley ball net, it \"penetrated\" the net by simply avoiding the net all together. so you would not expect to see a new visible hole in the net. Now if I shot a tennis ball at thin layer of clay, it might penetrate in a different way, by shoving aside the clay and leaving a visible hole. This is unfortunately what happens when people are hit by bullets. So, back to radiation. There are types of radiation that do leave holes. But you asked about visible holes. I'm not 100% sure what you meant by this as I assume you understand that radiation is made of very small things, much too small to leave a hole visible to the naked eye. however, with powerful microscopes, we can sometimes see the tracks left behind by certain types of radiation that was big enough and powerful enough to leave a \"trail\". For a macroscopic example see [ URL_0 ]( URL_1 )",
"Think of everything around as pants and radiation as farts. Although you don’t see any holes in the pants there are tiny holes that the farts can get through and allow people to experience the fart in all it’s glory. The pants are everything around us and Radiation is the fart 💨.",
"It's not the matter that's being transferred, it's the fields. Imagine it like blowing of winds. Some things stay undisturbed like stones, some thing shake like trees and somethings fly up like paper and dust. Everything is made of material and has a structure. Some of these structures are disturbed or break from radiation and some don't.",
"Just like water can soak through your clothes without leaving holes, but it can also slowly leak through paper, or a towel. Everything has holes, some are just bigger than others. With radiation you are talking about very small atomic particles, and those go through a lot. Different radiation has different size particles and go through different things; some radiation is more like light - it’s not even matter. Some gasses are so small that they go through stuff as well: Hydrogen is really hard to store because just like radiation, it’s so small it leaks through everything!",
"we are the scale or giants. as we zoom down smaller and smaller, you start to see the sub atomic structure of multi cellar organisms, when high speed radiation shoots through your body, it smacks electrons off their bonds, all over the place, messing with your living cells and DNA within your cellular structures, there may be zero evidence of holes beyond irreparable damage to the point your skin starts dying, you start to bleed from every orifice. Fun stuff. The big takeaway for knocking off electrons is they cause the breaking if chemical bonds, destroys vital proteins, etc. URL_0",
"Here's one super abstract when you think about it. Particles are super duper tiny, and they don't really touch anything in a physical way. What they do have are super strong force field surrounding them (think like the magnetic field around a magnet), and these force fields are how they actually interact with stuff. So now imagine one of those videos online where a person gets inside of a giant clear plastic ball (sort of like a hamster ball) and rolls down a hill. They never really \"touch\" anything, but the ball does, and the ball travels with them, so they can effectively \"interact\" with stuff. And you could also \"interact\" with them using the ball. So imagine now that you are waiting for them at the bottom of the hill, and let's also imagine that you're 50 ft tall. And when the human hamster ball with a person inside comes up to you, you run up to it and give it a field goal style soccer kick, and the ball and the little person inside sail off into the sunset never to return. But you never really touched the person, you just kicked the plastic ball and the little person sailed along for the ride. Now let's imagine that we replace the person in the hamster ball with a super powerful magnet. Let's now also imagine that we now make the sloping track out of metal, and we replace your foot with metal as well. With his new arrangement, the exact same thing would happen. The super powerful magnet wood float above the ground without ever touching it, and sail down the hill towards your foot And if you did a slow motion video capture when you went in for the kick, you would see that your foot approached to the magnet, but the magnet began flying away from your foot without the two of them ever actually touching. But magnets can repel as well as attack. And particles are like \"complex\" magnets because they can have multiple different \"kinds\" of force fields up at the same time. So they literally can be attracting another particle with one of their force fields, and pushing it away with another force at the same. Think, \"Oh God I need you near me!!! No wait... not that close...\" So the particles form like a net, or a lattice (think like those old school 1970s bead curtains, but without the string). So each particle clings on to all of its neighbors super duper hard, BUT pushes them away even harder if they get too close. So what you see as a physical wall, is really a cloud of particles made up almost completely of empty space, with the super tiny particles clinging on for dear life to their extremely distant next door neighbors, but always maintaining a tremendous distance from anyone else at the same time. So NOW when you swing your metal booted foot (from way back up top when you kicked that magnet) at the wall, usually one of two things happens. 1. The \"attractive\" forces between the next door neighbors particles in the wall holds up, and your boot bounced off (think ping pong ball vs a wall). 2. OR you kick hard enough and your boot physically breaks those bonds of attraction and soves it ways past the particles (think NFL linebacker) and leaves a hole. AND radiation is the same way. Remember that radiation is just the name that we give for the electromagnetic field as it moves through space. EM radiation is made up of photons and includes visible light, UV, infrared, X-Rays, cosmic rays, gamma rays, radio waves, etc. So when radiation hits a wall, it might. 1. Bounce off like a ping pong ball. This is actually how you \"see\" things. Visible light has a pretty low energy, and it can't really penetrate through most things So the reason why any object at all looks solid to you, instead of looking like what it really is (which is an almost completely empty cloud of particles), it's because that visible light when trying to move through that wall, tries to violate the personal space and get too close to those particles, and their repulsory force field kicks the light right back out at you towards your eyeballs, and that's what you see. SO what happens when EM radiation penetrates the wall? Why doesn't it leave holes like when you kick a hole in the wall? The answer is because light is made up of photons which are extremely extremely tiny. So when they don't have enough energy to push through the repulsor field of the particles that make up the wall, they just bounce back towards you. But when they DO have enough energy to pass through the repulsor fields on those particles, there's so much empty space for the photons to move around in, they can pass clean from one side of the wall to the other without ever actually touching anything or having to move anything out of the way (unlike your boot, which actually had to move particles out of the way in order to get through) That isn't to say the radiation doesn't have any effect at all on the things that passes through. Quite the opposite. High energy radiation positively shred the things that passes through. But because each individual photon is so tiny, all that damage is only going to be on that super tiny particle level. So if you get hit in the chest with a lethal blast of radiation, it's not going to put a hole in you. In fact you probably wouldn't even be able to feel it. Because all those photons were doing on the way through your body was just moving one particle a little bit this way, another particle a little bit that way, nothing you'd even be able to feel. But on your most fragile bits (like the DNA inside your cells) this can cause irreversible damage. Please let me know if this helps and if you have any additional questions at all!"
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m2qpfh | Is every single sperm cell the same? Does it matters which one fertilizes the egg or every single one from the same batch would generate the same person in the end? | Biology | explainlikeimfive | {
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"No, every sperm cell contains a random recombination of the father’s genome. The same is true for egg cells. That’s why siblings are generally genetically different, only having 50% of common genes on average.",
"No, they aren't. Each has a random half of the man who produced them's genes (along with any errors produced in the process, any potential damage done by environmental factors, and so on). That's why nonidentical twins exist. Two different sperm fertilize two different eggs, producing two different genetic sets (and thus twins that share the same amount of genetics as any other siblings). Identical twins happen when a single egg is fertilized by a single sperm, then splits in a way it's not normally supposed to to produce two copies of the fertilized egg. (More generally, it's also why identical twins differ from normal siblings.)"
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m2r4sd | What is NFT Art Theft? | i'm reading a lot of complaints from other artists that art theft is now easier than ever thanks to crypto NFT tokens - as far as i understand, now art thieves can attach an NFT token to an artwork and claim it as their own? i don't really understand that, because just claiming it as you own doesn't automatically take away the copyright of the creator of the artwork? | Technology | explainlikeimfive | {
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"If I claim a NFT on a piece of art and then I sell that token, I am still profiting from the artists work. If the person I sold the token to then sells it to someone else, who can say that exchange wasn't legitimate? If the original artist tries to sell their original art, they might not be able to sell, or will have to sell for less if they do not control the token. The danger to the artists depends on how seriously people take NFTs. Artists are naturally very worried about NFTs because of the possibility of theft, so they will want to emphasize the flaws in the NFT model. They also probably should want to be very proactive about it, because 'blockchain' tends to make people believe something has legitimacy. It's worth noting that NFTs are not even the first instance of this behavior. It is a common complaint that there are bots that search for unmonetized music on youtube to claim, resulting in people getting copyright strikes on their original content plus adds on their videos that they don't get paid for."
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m2rbtz | Why do we grow out of wetting the bed? Is it psychological or physiological? | Biology | explainlikeimfive | {
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"text": [
"Physiologically, the bladder becomes larger and needs to be emptied less often. Children also become more responsive to the nerve signals, waking them up to go to the toilet."
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