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neo1un | Why is it so easy for you to use a screw driver to loosen/tighten screws, but nearly impossible/very hard to do it with just your hand? | Physics | explainlikeimfive | {
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"To tighten a screw by hand, you're limited to gripping just the head. This would require you to pinch it between two finger tips, which has a maximum grip strength of maybe 20 pounds. Friction between skin and metal is iffy, so we'll say that you only get 10 pounds of grip. That is applied at a distance of, at best, a quarter inch from the center. This gives you a torque (rotating force) on the screw of 2.5 inch-pounds. With a screwdriver, you could instead grip with 60 pounds at least since you can use your whole hand. On top of that, you're twisting farther from the center - maybe 3/4 of an inch instead of 1/4. That allows for 22.5 inch-pounds, assuming the same friction from earlier. With a good rubber handle, friction may also be noticeably higher.",
"Your fingers cannot squeeze the screw tight enough to turn it without slipping. If you were wearing special non-slip gloves then maybe it would work, but then the thickness of the gloves would make it hard to squeeze the screw at all",
"The handle of the screwdriver is what makes it easier. If the handle was the same diameter as the screw, it wouldn't be any easier (except that it might be easier to grip it so you could apply more force). Since the diameter of the handle is larger than the screw, you can apply more torque and then turning the screw becomes easier.",
"Levers convert a small force applied over a long distance to a large force applied over a small distance. A long lever lets you lift a heavy weight with less apparent effort. The rotational equivalent of linear force is torque. The handle on a screwdriver has a larger diameter than the screw head. The wider the handle, the less apparent effort has to be used. It's also easier to grip the screwdriver. You use different, stronger muscles to make a fist (around the handle) than you do to pinch (the screw) with your fingertips."
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neo2t2 | why do turtles have long life? | Biology | explainlikeimfive | {
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"Because their organs go through the ageing process much more slowly than those of most other organisms. And it will be really great when we figure out why that happens. Unfortunately, we currently have no idea."
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neogjg | What is it about glass's molecular structure that makes it to where a timy scratch allows it to cleanly break in 2? | Chemistry | explainlikeimfive | {
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"Basically glass breaks fast because it has zero plasticity. It has zero plasticity because it's a giant blob of disordered interconnected atoms that cannot move relative to eachother. If you break an atomic bond with enough force, the load just gets transferred onto the next atomic bond which breaks and so on and so forth. This doesn't happen with plastics and metals. Plastics are a tangle of carbon chains which can slide past each other, metals are a soup of atoms sharing electrons. When you heavily load the material, some of the most highly loaded molecules move about instead of bonds breaking and the material bends permanently (plastic deformation). When you crack something (a scratch is a type of shallow crack), the geometry of the crack concentrates load at it's tip. In ductile materials, you get a small amont of plastic deformation at the tip of the crack and this shares the load out over a large amount of material and the crack stops. In brittle materials, when you load the material, the stress at the crack tip can be high enough to break the material adjacent to the crack tip. A longer crack concentrates the stress more, so the crack breaks more material and this cycle continues with a crack that shoots through the material incredibly fast. The crack will take the shortest path through the material's thickness since all the load acts on the smallest area in that plane. This gives a straight break through the glass.",
"There are two main things at play here. One is the ability of a material to stop a crack from growing. The second is how long a crack needs to get before it's self-propagating. Most glass you're familiar with ranks poorly in both of these, where a deep surface scratch is enough to act like a large enough crack to make the material fail easily. In comparison, the aluminum alloys for airplane wings can support cracks multiple inches long, and are actually measured with rulers during the airplane's lifetime."
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neoui7 | The ads I see in fremium gaming that claim you can "earn real money just by playing!" aren't these just scams or are they real? | I play this interior design game on my phone and I constantly get ads for other games that claim you can "win real money just by playing!" or "win real amazon giftcards by playing games!". I always just assume these are scams, but I'm curious: does anyone have any experiences with these "realmoney" games? Are they real or is it just another way for hackers to steal your info? | Technology | explainlikeimfive | {
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"bit of both. this is generally these companies having deals with ad companies ot get your data/clicks in hopes you'll buy into them. honestly wouldn't recommend as this generally is how you end up with a crapload of spam mail and potentially leaked info.",
"Depends on the game. Most of the ones you see on a regular basis are probably legit in terms of \"can you make ANY money?\", otherwise they'd get complaints and get pulled from the marketplaces. Now, how much money, that is usually the grey area. Typically you have to sink a ton of time into those games to make any significant return cause they gotta make more money on ad revenue than their paying you to play the game. So you might end up with a couple bucks a month or maybe a week if your hardcore playing but it'll never be enough to really make a difference unless you are finding some way to cheese the system 24/7.",
"I'm sure a fair number of these are scams. But it's possible for this kind of incentive to be legitimate, considering the following two facts: - Most players don't win much - It's hard to withdraw your money If you win $1.37 playing the game for 10 hours, you're probably not going to bother going through the hassle of figuring out how to actually get paid. You're also not necessarily going to spend 1000 hours to win a somewhat meaningful amount of money (more than $100). So they may actually pay out non-trivial amounts to a few very dedicated souls who love the game (or get obsessively fixated on the idea of free money) and put in hundreds or thousands of hours. But there are thousands of much less dedicated customers with tiny balances that they never claim. Gift cards are a variation on the theme. Unless you have a coder and an artist who work for free, even the cheapest games generally have $thousands in development costs. So buying say ten $100 gift cards isn't large relative to the game's total budget, and then you can honestly say people *can* win a $100 gift card by playing. Of course if 10,000 people play the game and there are 10 gift cards to go around, that means 999 players out of 1000 will get $0. This kind of thing's not exactly a *scam* in that the \"winning real money\" part is *technically* true. But if you're having fantasies of becoming a millionaire or quitting your job to play games full time, keep in mind that you'll probably be \"earning\" much less than $1 an hour.",
"Yeah they're *essentially* scams, but not in a hackers stealing your info sense. They're basically glorified ad platforms. Companies pay these platforms to tell you that they'll pay you to play their game. As far as the game company is concerned, it's paying money to acquire players, just instead of an paying it to an ad agency that tries to make the game look like it's worth playing, it pays it to an ad agency that says it'll pay you if you play it. So if our ad platform is Company A and our boring game is company B, and you are Consumer C, then B gives money to A, and A tells C that they'll give C money if C plays B's game. As far as B is concerned, it has gained a player, a player who might just like the game enough or be enough of a gambling addict to spend money on it. Meanwhile, C believes that they are being paid to play this game, when in reality company A has a bunch of obscuring factors that prevent C ever taking their earned money - things like \"you actually get entered into a lottery system where you can win the money\" or \"You can only take your money out once you've racked up £10 from playing 20 hours of stupid games\". So in essence, C has given money to B and B has given money to A, all based on the lie that A will give money to C (although imagine that C and B are the average consumer and company, not the individual - most Cs won't spend anything, but the occasional one will and that's enough). These methods can also be used by companies to get what is essentially a beta test audience for a game that otherwise wouldn't be good enough to get beta testers. In short, it's a platform for advertising specifically to people stupid enough (or desperate enough) to think that 10p for essentially doing 30 minutes of work is a good deal."
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nep8rw | Why does the pitch of an audio clip go higher or lower when slowed or sped up? | Technology | explainlikeimfive | {
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"The pitch is directly related to the frequency of the sound wave measured by the number of wiggles over time. If you speed up or slow down a song, you're affecting the \"time\" part of the pitch. Because frequency is \"over time\", slowing down or lengthening the time lowers the frequency/pitch. Likewise, speeding up or shortening time raises the frequency/pitch.",
"Typically, this would be done by speeding up a tape. Pitch is defined by frequency of notes. Higher frequency = higher pitch, lower freq = lower pitch. Imagine a length of paper tape with marks on it at regular intervals, say 1 inch between each. Move the tape at 1 inch per second, and you have frequency of 1 mark per sec. Double the speed, and the frequency will be 2 marks per second. Double it again, and the frequency is 4 marks per second. That's how you increase frequency. Frequency goes up, pitch goes up."
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nepf2w | Why is 20/20 vision considered normal? | Why do optometrists only correct vision to 20/20? Do we have the technology to have even better vision, and we just don't do it? | Biology | explainlikeimfive | {
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"It's literally the baseline of average. Just in case you don't understand what it means it literally means I see at 20 ft what you see at 20 ft. So by that definition it is the normal average standard of visual acuity. Quite often with corrective eyewear people do experience better than average vision, using myself as an example I have 25/20 vision with my glasses on. I see you at 25 ft what you can only see at 20. But as far as I know there's no definable methodology they can use to be able to say I will improve your vision x amount. All medicine can do is make the best corrections they're capable of often that results in average sometimes below average and sometimes above average.",
"20/20 vision is normal because that's what normal human eyesight is. You could say that superhuman eyesight is \"normal,\" but that's just arbitrarily changing the definition of normal. There is the possibility to enhance eyesight, but it's not something that can be regularly planned for. Some people who undergo laser eye surgery report having better-than-normal vision after the procedure, but many people also report worse-than-normal (but still improved compared to pre-surgery) vision. So there's no process by which people get better vision; it's pretty variable based on the person.",
"20/20 vision is based on the measurements of average vision by Herman Snellen in 1862. It's supposed to be average by definition, although quite a few children actually have better eyesight than that. We have the technology for better eyesight and we use it. Magnifying glasses, binoculars and telescopes the all examples. I've been offered glasses that would give me 20/15 eyesight, although since my current eyesight is 20/25 I've never bothered to get them."
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neq9rj | what is Gnosticism? | Other | explainlikeimfive | {
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"Gnosticism says that we are spiritual beings trapped in a material world. Gnostics believe that we need special knowledge (“gnosis” in Greek) in order to escape this material world. Many Gnostics believed that Jesus was sent to earth to bring this special knowledge, but most early Christians didn’t think Gnostics were true Christians.",
"Gnosticism is a religious movement from the first couple centuries AD/CE. It is a more spiritual and mystical belief rather than one of rules and authority—Judaism and Christianity are more rule orientated. Gnostics recognize Jesus as an important figure, but did not agree if Jesus was part of god or a man. Also, they have a Zoroastrian influence in that they have two gods, one good and one evil. The early Christian Church declared this belief a heresy. Gnosticism eventually evolved in Manicheism, another Christian heresy. EDIT: As an additional historical tidbit, the Cathars/Albigensians in southern France were a Gnostic movement. Early in the 13th Century, Pope Innocent III started a twenty-year long Crusade against them killing between 200,000 to a million. It was the single largest of the Crusades, and it took place France. It was during this crusade where the famous expression \"kill them all, and let God sort them out,\" came from. (The exact quote is *Caedite eos. Novit enim Dominus qui sunt eius.*—Kill them. For the Lord knows those that are His own.)",
"Gnosticism was this weird fusion between christian/jewish mysticism and neoplatonic philosophy, and it's roots lie in the religious question \"If God is good, why is there evil in the universe?\" And the gnostic answer was that the universe isn't Gods creation. In gnosticism the physical universe is a prison/illusion, a creation by the demiurge (the maker) a lower divine or semi-divine being who created an imperfect physical universe. In gnosticism salvation was not due to sin or repentance, but knowledge (gnosis). By knowing God your soul could escape the imperfect universe and reach paradise. Most gnostic sects believed that Jesus was a messenger of the true god, and through his esoteric (secret/hidden) teachings you could gain knowledge of God and achieve salvation. Other sects believed that John the Baptist was the true messenger and Jesus the false one, one created by the demiurge.",
"Gnosticism was a Christian mystical or wisdom tradition where the goal of your worship was direct experience of God or the Godhead. It's practice of contemplation is similar to the practice of meditation in Eastern wisdom traditions. Meister Eckhart could be considered a Gnostic when he declares, \"The eye with which I see God is the same with which God sees me. My eye and God's eye is one eye, and one sight, and one knowledge, and one love.\" This unity with God is something common to all wisdom traditions and it reminds me in particular with the Buddhist concepts of the One. I've heard the opinion that the Gnostics disintegrated where the Buddhists succeeded because the Gnostics emphasized individual experience over collective structure where the Buddhists managed to balance the two.",
"Gnosticism is a flavor of Judaism/Christianity that believes that the God of the Old Testament(Yaweh) wasn't the real God but was a soulless physical abomination called the Demiurge accidentally created by an aspect of the Real God. This Demiurge, lacking divinity was unaware of Real God, and so thought that it WAS God. He created the physical universe as well as Adam and Eve in his image, and demanded to be worshipped under threat of punishment. Real God took pity on them and gave them souls, and then sent the Serpent into the garden to give them knowledge of their own spiritual nature so that they could escape the Demiurge's rule as well as transcend the physical world into the spiritual. In this interpretation original sin doesn't exist, and Eve eating the fruit and gaining knowledge wasn't something that damned humanity, but rather saved it. Depending on the version of Gnosticism, Jesus is still divine, and is of the Real God, not the Demiurge. Through this, it provides an explanation as to why Old Testament God is kind of a tyrant/psycho who smites people and makes rather horrid demands under threats while Jesus was all \"peace and love.\"",
"Gnosticism is one of the earliest interpretations of Christianity. There are various schools of it like how Protestant and Catholic are schools of Christianity. The main tenants of Gnosticiem are that there are various godlike beings that were birthed by the godhead, one of these created our universe and and another corrupted it (think Satan). Life was instilled into our world via Sofia, an essence of the being that created our world. And gnostics believe that they can return to the soul of the creator god by a form of enlightenment. How does this relate to Christianity? Well the soul is the Sofia and Christ is an emenation of the godhead, projecting into this world without taking form in it. And thus is uncorruptable by the sin, so to speak. The Christ came to alert the creator god (through his Sofia offspring that is us) of what has occurred as he is essentially \"dreaming\" our reality while another god corrupts it for power. If you've ever played Elder Scrolls, this is the religious that their mythology was based on.",
"Tron: Legacy Dark City The Truman Show The Matrix Could all be Gnosticism the Movie. Xenogears. Gnosticism the Game.",
"In a slightly related note, there's a hugely influential sci fi novel from the 1920s, \"A Voyage to Arcturus\" by David Lindsay, that is very gnostic-leaning and well worth a read.",
"a prominent heretical movement of the 2nd-century Christian Church, partly of pre-Christian origin. Gnostic doctrine taught that the world was created and ruled by a lesser divinity, the demiurge, and that Christ was an emissary of the remote supreme divine being, esoteric knowledge (gnosis) of whom enabled the redemption of the human spirit.",
"You are trapped in a illusory reality as big as the entire universe created by a crazy evil god. Your quest is to find the knowledge to free yourself and get to the spirit realm. The rest of the world is made of people like you, but some are predestined to get free, others will be slaves forever. Basically the Matrix plotline or your average survival horror game.",
"Daughter of a Gnostic father here: In short, the name “gnosis” means knowledge of spiritual mysteries. The name originates from late 16th century Greece and translates to “knowledge” It’s a possession of a higher, divine knowledge. My dad has been teaching me his learnings for nearly a decade now. Those with a true understanding are lead to the salvation of the soul. He’s incredibly wise, and it’s comforting to speak to him about Gnosticism, but it’s still difficult for me to grasp.",
"Gnostic means \"with knowledge\". Inversely Agnostic means \"without knowledge\". You'll often hear the term Agnostic when talking about religions and personal beliefs in a higher power. Theism is the belief in a god. Atheism is the belief in no god(s). And Deism the belief in many gods. You can combine these three words with Gnostic or Agnostic to create new meanings. For example: An Agnostic Atheist is someone who doesn't believe in god but isn't really sure if there is or isn't a god. While a Gnostic Theist is someone who believes in god and knows that there is a god. An Agnostic Deist is someone who believes in many gods but isn't positive that they are correct.",
"I think a new Gnosis is in order that recognizes in the image/idea of the Spirit and the Bride, a participatory eschatology via a commingling of the Spirit of God and man, in a consummation and a new creation, whereby the outer world is reflected from the inner as a first cause and arrow of authentic leadership & Civility. At the heart of Jesus' death and resurrection is an evolutionary and \"involutionary\" principal that goes the very heart of life & the inward felt experience of a transcendent joy and triumph, and one that doesn't need to cleave the physical from the spiritual. We are bought up by Christ and drawn to His bosom; in the world, but no longer *of* the world. Gnosis as self-knowledge and God-knowledge, not an article of \"faith\" as a mere belief but more of a leaning on and an abiding trust in, framed by that fundamental relationship between beloved and beloved other. I-thou. Abba. Father! Here's an interesting read that echoes some of these ideas. [ URL_0 ]( URL_1 ) Quote: \"God has no wish for any other means of perfecting his creation than by our help. He will not reveal his Kingdom until we have laid its foundations\" \"The Kingdom of heaven is spread out upon the Earth but men do not see it.\" \\~ Jesus, the Gnostic Gospel of John, The Nag Hammadi Library.",
"To add on to this question.... How is it pronounced?",
"So....are Mormons Gnostics? They believe they have special spiritual knowledge that is required to get back to our spirit father in heaven. But they are pretty literal things like secret handshakes and some ceremonies.",
"The main tenant of gnosticism is knowledge, or that one can attain knowledge of God. (Think opposite of the agnostic.) Throughout history there are many groups that claim to be gnostic and still some today. If you want to know what gnosticism means to a “gnostic” person, or group, you will have to ask them.",
"Gnosticism was a version of Christianity shortly after Jesus lived. They believed Jesus brought them secret knowledge (gnosis, from which their name comes) that would allow them to escape this world and our bodies to go to a better, spiritual world when they died."
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neqk5j | when you pick something up that is lighter than you expected, why do you feel like someone pushed you back? | I think maybe it has to do with you giving too much force or something, but why do you end up being thrown back instead of if sort of balancing out when you realize it’s lighter than you thought? | Physics | explainlikeimfive | {
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"Your brain is pretty good at judging your weight balance and positioning itself right to counter lifting an object. Just one of those skills you develop over time. But if the guess is off and you have too much weight back it all gets thrown off: you're doing it to yourself but it's off the expectation and startles us",
"What you don't realize is that there is a lot of motion that goes into lifting something. It isn't just hands or arms. It's an entire shift of your body. Your brain makes a judgement call and shifts such that the new weight you have picked up will balance you out. If this new weight is lighter than expected, the shift is too much. Really, you threw yourself backward, so when the object isn't heavy enough to balance you, it feels like someone pushed you back. But you did it to yourself.",
"You can use your legs to pick something up or your can use your back. Most often, people will use both. You are expecting more work than necessary so you position yourself in anticipation. As you put extra effort into the lift, it takes you further than expected - and now your back is in a position where you have less balance. It is in that moment of realize that you have lost balance, that your mind pays very particular attention, maybe even startled when you consider you were expecting to be balanced!"
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neqrra | If we store more fat after fasting, then is that why we eat vegetables? | I heard that if you don't eat for a week, and then if you start to eat, your body will store more fat because it thinks that food is getting scarce, therefore fasting is not a reliable way of losing weight. But if we eat Dietary Fiber vegetables (food that we cannot fully process) instead of literally starving ourselves, then does the body say "oh look, the stomach is full, therefore no need for storing fat" ? Does this mean that if i make my diet 70% vegetables and 30% soup, will i start to lose weight? | Biology | explainlikeimfive | {
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"The human diet is still poorly understood and even nutrition is a very complex topic. We store calories in excess of those we need to function as fat. We can then convert the day back into sugar when our calorie intake is less than needed for our daily activities. When we run a significant calorie deficit for an extended period of time out body will consume our fat, and muscle to keep calories for our brain. The variety of foods you eat is important to avoid malnutrition but it doesn't matter if it was meat or vegetables, if you are at starvation level intake your body response will be the same. The mixture of vegetables and meat is not what is critical is the calorie content. There high calorie vegtables avocado is high in fat and thus high in calories.",
"Your body isn't going to magically store more fat. That's a myth. Your body stores as much as it can when it can. That's the point of putting on fat.",
"Your body can't store more fat unless you eat more calories than you burn. This is the concept that people have trouble with because generally speaking, people suck at counting calories. Also even if you do put on more fat after the fast is over, unless you go back to eating as much as you did pre-fast, you will still have less total fat than before",
"> I heard that if you don't eat for a week, and then if you start to eat, your body will store more fat because it thinks that food is getting scarce, therefore fasting is not a reliable way of losing weight. That is 100% bullshit. Your body is not capable of thought, only your brain. It doesn't 'know' you just fasted. What people who resume eating after fasting experience is rapid weight gain in the form of water, as resumption of carb intake will require water(500g of carb will bind with 2kg of water). If you eat more kcal than you need per day, the excess is stored as fat. Track your kcal intake and look up a TDEE calc to help you set a goal weight. If you don't count kcal, your body still will."
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nervye | How were websites created before web hosting services? | I know that you can create websites using services like WordPress, but before those existed how did people code websites and put them on the internet? | Technology | explainlikeimfive | {
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"< HEADER > HTMLv4 static web pages. < \\HEADER > < BODY > Geocities was a very popular tool with templates to make static HTML pages, or write your own code. You could host there, and setup a CNAME in DNS to get your custom domain to point to it. There were also services you could rent space on other people’s servers for a monthly fee, just like today, but again: static HTML. You could also setup a web server in your home. Today it sounds scary AF to open a port in your firewall to a web server on your home network, but frankly back in 1990 almost nobody even had a firewall to speak of. < \\BODY >",
"A web hosting service is someone else running a web server on a computer. Before they existed you had to runt it on a computer you owned. But they have existed for a long time. GeoCities is likely the first well known and it was launched in 1994",
"All things like Wordpress do is help automate the creation of the code for your website. A webpage is still an html document at the end of the day - if you want to see it, most browsers have the ability to \"view source\" in the developer tools. That source is the actual html code of the page. Back in the day, we just coded the html by hand. We'd type it in a program like notepad, save it as an .html file, and upload it to the correct directory of a webserver.",
"Your computer is on the internet, if you know what to do you can relatively easily set up your own computer as a basic web server that you can connect to and browse a small website All a hosting service is is just someone else’s computer, they also have other services to help you and make it easier to use, but at their heart, there is just a computer connected to the internet, nothing you can’t do yourself with your own hardware at home",
"> before those existed how did people code websites HTML, CSS, Javascript: Much like most of them still do. Wordpress, squarespace, Wix, and the likes are neat for people with little time, resources, or coding experience, but most websites made by bigger companies won't use them because they can be quite limiting if you want to do anything other than make a blog, a snazzy landing page, or a standard webshop. While the technologies of course have changed and have gotten a lot more convenient and advanced you can still open up notepad, write some HTML in there, CSS to style it, and Javascript to make it do more complicated functionality, and any browser will just run that out of the gate no questions asked. You can then set up a basic webserver that can serve that file straight from your own computer. While writing websites in straight HTML without any other supporting frameworks is pretty slow it's perfectly doable and was more or less how it was done for decades. At the end of the day that's still what all websites run on: A combination of HTML, CSS, and Javascript. If you right click on any website and select \"inspect element\" you'll see it: the html that's describing the website you're on.",
"You're conflating two separate things: how did people *create* websites and how did people *host* them. \"WordPress\" does a bit of both so I guess that's why you're confused. WordPress is the PHP-based software (Content Management System) which generates the website, URL_0 is the web hosting service that will host a WordPress website for you. Creating websites is easy. HTML, CSS and JavaScript scripting/markup languages are the basic requirements to build a site on the World Wide Web. They have been for about 25 years and haven't fundamentally changed that much since then. These are all just plain text files that any web browser can render. You can use Notepad to make them if you want. Sure these days people have fancy source code editors and frameworks that do most of the groundwork of creating a new website, or content management systems which have all the code and the user just adds the content, or website builders that use templates or drag-and-drop interfaces to add features. But you're still getting the same code in the end. Databases and programming languages (like PHP, Java, C) have existed for just as long or much longer, and were easily integrated into the web development stack to create more dynamic websites. As for hosting, well a web hosting service is just a third-party company that will run the servers that your website is hosted from. They've existed basically as long as the public World Wide Web has. So there wasn't really a time without them. But if you're not paying somebody else to host your website, you would need to host the site yourself. That means running a computer as a server, with the required software to host your site. That's still a viable option today if you just want to host a small personal website for yourself from an old desktop PC, or if you're a big company with the resources to manage your own infrastructure."
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nes4es | Why do photorealistic paintings don't give us (most of the time) an uncanny feeling compared to 3D renders? | Other | explainlikeimfive | {
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"1. Because they aren't moving so we aren't trying to interpret them as alive 2. Because it's an imitation a *photograph*, not the actual person or animal in a film or in front of you 3. Because of exceptional quality, and what a lower quality version looks like Look at the graph from the wikipedia article: [ URL_1 ]( URL_2 ) The effect is much less pronounced for still objects, and that's still referring to actual objects, not static images. CGI movies and robots are the main two examples of uncanny valley, which are about observing or interacting with human-like or animal-like creations actually performing actions. [ URL_5 ]( URL_5 ) When you have something photorealistic, it's imitating, well, a photo. A robot or a CGI movie are imitating a live person. One theory is that if it looks very real but not alive inside, we get freaked out and think \"dead body but it's moving!\" The quality is also a factor. When you're doing a 3D *movie,* you can't generate the kind of quality needed for every frame. When you have a robot, either they are unnaturally still (uncanny), or you have to simulation natural motion, which is very very challenging (so again, we get uncanny) Look at this image: [ URL_3 ]( URL_0 ) Source: [ URL_4 ]( URL_4 ) For high quality, static images that were computer-generated, it usually *doesn't* freak people out. It either actually fools someone \"yup that looks like a photo of a person\" or our brain treats it similar to photorealistic paintings: wow this artist *almost* made a portrait look like a photo! When painting are off the mark, they look like, well, less-good attempts at a photo-realistic painting. We're able to identity it as \"art that is attempting to look like a photo\", not \"I thought that was a person but they started speaking and now something's off and I'm freaked out\"."
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"https://en.wikipedia.org/wiki/Uncanny_valley",
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nesad2 | How do we blink? | I was just thinking, how do we blink? Normally we move a muscle by pulling it but there nothing pulling it down right? The best I could come up with is that in the sides are the muscles. But if that were the case if you closed your eyes very tightly it would pull to the side. So how do we physically blink | Biology | explainlikeimfive | {
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"The muscles that control the eyelids are vertical, with their relaxed state being closed. They're contracted when the eyes are open.",
"by not pulling the lids up anymore, the lids close. that's why it's getting harder to keep your eyes open after a long day: your eyelid muscles are tired and need rest."
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netzc1 | What is insider trading and why is it illegal? | Economics | explainlikeimfive | {
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"Trading in a stock using information unavailable to the other party in the stock transaction. If you know your company is going bankrupt, and sell yours to people who couldn't kno that, you are cheating them. Cheating is bad.",
"This specifically applies to publically traded stocks, where anybody in the public is free to trade (buy or sell) a piece of ownership or shares of the company. When you buy stock in a publically traded company you are essentially now an owner, and in theory have the same rights as huge investors who may own thousands or even millions of times as much stock as you. However the big investors include founders and board members and decision makers who are much better placed to be tuned into and capitalize on changes in the companies fortunes than you are.. To lessen the unfairness, the company is supposed to publish regular reports on its finances and operations, and since anybody might own stock, this information is made available to the whole public. As well, if there is unexpected good news or bad news, these insiders are not supposed to buy or sell stocks until the news is announced to the world. If instead, they act on secret information, they are not treating you fairly as one their fellow owners.",
"The theory behind stock trading is that everyone has access to the same information; basically, everyone is playing on a level field. All the information that the \"super-investors\" have is, generally, publicly available; you just have to spend the time looking for it, understanding it, and interpreting it. That's the theory. Insider trading is making a stock trade based on information that isn't publicly available; ie, an insider told you what was going on. This gives you an unfair advantage, since no one else knows that piece of information. This is considered illegal because it's taking advantage of the rest of the market. So if your friend tells you that his company is about to sign a big contract with another company, that's insider information. Any trade you make with that information is considered insider trading. If your friend tells you that their company is about to go bankrupt because they had a contract get cancelled, that's also insider information. In general, you're not allowed to trade with any information except that which is publicly released, like earnings reports, quarterly/annual reports, press releases, etc. made by the company.",
"If you work in an important position at a company you are allowed to own and buy and sell stocks of that company. But there is a certain list of things where if you know about it you absolutely positively have to announce it happened before buying and selling anything. It's illegal because it's super easy to come up with scams. Where you know for sure what is about to happen but you pretend you don't know anything.",
"In short, it’s the same reason cheating in a casino is illegal. If you know the direction of the stock due to proprietary information that only execs/insiders have access to, you can make your bets accordingly. It’s like if you installed magnets on a roulette wheel and could control if it hit red or black. Insider information works the same. If I know the CEO is about to be charged with embezzlement and it isn’t public yet, I could short the stock knowing it’s going to plummet.",
"It's kind of what it says--it's trading by an insider. Let's suppose, for example, that Apple developed an amazing new technology--one that would allow cell phone batteries to hold enough charge to last three months, without recharging. That technology would be worth a *lot* of money, to Apple--many billions of dollars. As soon as they publicly announce that technology, Apple's stock is guaranteed to go way up. So, if someone who works for Apple and knows about the technology decides to buy a whole lot of Apple stock, before any public announcement is made, he can make a lot of money, using his unfair advantage as an insider at Apple. But a lot of people would consider that kind of advantage to be unfair, so the government made that kind of \"insider trading\" illegal.",
"Let's say I have a super rare Pokemon card. If I sell the card to you for a lot of money, and the next day Nintendo says \"Hey we're going to print a lot more of those cards\", and the value of the card sinks. I got lucky and made more money than if I had waited, and you got unlucky because you could have bought it the next day for a lot less. That's my good luck and your bad luck, and totally legal. But, if it turns out my friend at Nintendo tipped me off the day before, so I rushed to sell my card, then I took advantage of you because I had secret information from the inside that helped me win and you lose. That's unfair and usually illegal. On the other hand, if I ***guessed correctly,*** or I found an unpublished Nintendo press release a day early, or did some other research to figure this out, then I am clever and profited from my cleverness and that's still too bad for you, but not illegal (in general). So you're allowed to work hard to get a market advantage. You're not allowed to use certain kinds of company secrets to get an advantage. It's complicated, because law and lawyers."
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nevcjl | what is happening to your skin when a callus forms? | Biology | explainlikeimfive | {
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"Ok, a lot of people are anthropomorphizing the body a little bit with these answers. The body doesn’t “recognize increased pressure/wear.” Actually the pressure itself damages the lipid shells of skin cells causing them to interlock and mesh together more strongly. Then when they die they are more tightly bound to neighboring cells and do not slough off. This process repeated over and over creates a crust of dead skin bound tightly to itself and the living skin underneath. It’s sort of a passive process rather than the active one most people are describing. Edit: Wow first gold, silver, etc. thanks guys, and also “slough”",
"I am by no means a medical expert and am answering from about 15 minutes of Google research. A callus is pretty much the body protecting itself when it notices that an area of itself gets more friction or pressure than usual. Basically the body saying \"hey I'm gonna grow some more layers of skin here to protect myself from the outer layer of skin getting rubbed completely off or from blisters forming.\" They're like nature's work gloves. Your body notices that section of skin gets used a lot more so it forms additional layers of skin to protect it.",
"So actual ELI5 would be that some of the tiny building blocks that make up your skin get smooshed together sometimes, and then more get smooshed on and stay that way until there's a big chunky bit, and that's your callus.",
"Your body recognizes the stress and wear on that spot and produces more skin .... along with more keratin. The keratin causes the skin to toughen and stick together instead of sloughing off like usual. The answer you’re looking for is the increased keratin (same as in your fingernails); it turns your dead skin into armor instead of it just falling off.",
"ELY 5 - skin grows and sheds at the same rate under normal circumstances. In instances where more pressure is applied to the skin, that balance is altered and a layer of dead (no blood supply) skin forms on the surface.",
"Your skin is basically an ablative coating for your whole body. Your dermal layer is constantly making copies of itself. When you have irritation in an area, your body signals those cells nearby to divide more rapidly. This is the long term solution to heal the damage, and hopefully prevent more irritation. Because the skin is building up much faster than it is being worn off, you get a thicker layer of skin that hardens because the oil produced in your oil glands can't get all the way out there."
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newu4q | WHY are the commercials always louder than the show?? | Other | explainlikeimfive | {
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"text": [
"So that they grab your attention so that you will hopefully watch them. If they were the same volume of the show you might not even notice it's now a commercial. You might be chatting away or playing on your phone. By making it loud, you will look up and see the commercial. You might not like it, but it will get your attention, which is what they are after.",
"So you can't escape the brainwashing. They overwhelm your senses until you surrender control of your bank account. No lie."
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newzr2 | What’s the importance of protecting old growth trees? | Earth Science | explainlikeimfive | {
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"They take a very long time to grow and establish that balanced ecosystem under them. If you cut them down, the ecosystem is disrupted and it will take 100 years for it to recover.",
"Old growth forests have a lot of benefits that younger trees or areas that humans have cleared and replanted don't have. One of the main ones is that older trees are bigger, so they can make more oxygen and clean up more air. Old trees are also taller so they can provide homes to more animals and birds who like to be high up. Depending on the type of tree they can also block a lot of sun, which controls the temperature of the surrounding area by keeping it cooler. This can be important as some animals and plants that live beneath the canopy layer of the tree can't handle a lot of heat. Another very important part is that older trees have bigger, deeper roots. This means they are better at draining and aerating soil so it doesn't get taken away by rain and so it isn't too wet. It also means the roots can bring up more nutrients. Older forests can also have some dead trees or plants, which would have been cleared away by humans if we didn't leave these forests alone. Those dying plants give back nutrients to other plants and organisms like mushrooms, worms and other bugs that break down the dead trees. Overall, Old growth forests are really important because they support more animals and plants than forests which humans clear out and replant. They support plants, bugs and fungi which humans might not realize are part of the original ecosystem as well. They help draw up moisture from the soil which is crucial to the water cycle and they clean more air and release more oxygen than younger trees.",
"To add to existing comments: Old growth trees provide habitat in ways that younger trees can't----some species of birds, for instance, only nest within the hollow cavities of old trees.",
"In 2019, I drove from Toronto to Tofino, BC (the western end of the Trans-Canada Highway on Vancouver Island) with my girlfriend. On the road crossing the island, there is a place called \"Cathedral Grove\". It's a section of the Macmillan Provincial Park, featuring some amazing old growth cedars. Even with the usual crush of tourists around, you still feel a sense of awe and tranquility in the hush, and see the beauty of the sun's rays bursting through the leaves, as the shafts of light reveal the splendour of the centuries-old cedars. It is both humbling and exhilarating, and unlikely to be duplicated in VR. That is why we need old growth trees.",
"It's not just the really old trees, it's the intact mature ecosystems. If you bulldoze an old-growth forest and replant the trees, don't expect to see the same diversity a hundred years later -- some species will recolonize, some won't, and some invasive (or just opportunistic) species will get a foothold that would not have otherwise. It doesn't grow back the same after the loggers and road-buildets and miners have been through."
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nex9c5 | Why does the stomach make noises when it is hungry and when it is digesting? Are there biological differences to the sounds? | Biology | explainlikeimfive | {
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"No food in the stomach and brain tells the stomach to get ready for food by contracting and produce juices. The noise is gases. Digestion noises are gasses and the contraction of those muscles to digest food.",
"The stomach is always doing its squishing job, and that inevitably involves creating bubbles. The sound you hear, and the difference between them, is the bubbles popping within whatever is - or isn't - in your stomach. The size of your stomach also affects it, but not as much as you might think."
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nexj3p | What’s the biological purpose for butt cheeks and their different sizes? | Biology | explainlikeimfive | {
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"text": [
"Our ability to walk upright. Quite literally the reason we have butts is because we evolved to walk upright, which requires a lot of balance and strength in the glutes to maintain as easily as we do. Different sizes is mostly just a combination of genetic diversity and strength training.",
"The [muscles in the butt]( URL_0 ) in general \"pull\" the legs backwards, so you can stand up, walk upright, run, operate a bicycle, and in general move your legs. Exercise can increase the size of these muscles, as they adapt to grow and provide \"sufficient\" pull power to move whatever body weight and/or additional effort you're making."
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nexrr0 | How should I interpret statistics like "The people of X country live on less then X U.S. dollars a day."? | I always get confused with statistics like that, probably because I have a shaky understanding of how exchange rates function in general. These stats usually come up for countries and peoples that are very poor, and I understand that it means in some way or another that they are struggling and in poverty, but I find it hard to really understand. For instance, I see an article by the World Bank which states nearly half the world lives on less than 5.50 USD a day. How do I make anything of that when I don't know how much 5.50 USD a day buys in their economy? Stats like that aren't really adjusted for cost of living, right? Isn't there some degree to which things in their local economies would also just be cheaper, and the cost of living lower? Why is the US dollar used as a comparison, when it isn't a country that uses the dollar locally? Note, I am not somehow disputing the severity of poverty in the world, just curious how this particular bit of economic data works. I suppose it ultimately ties into international trade, but nonetheless if anyone can explain what the implications of these kinds of statistics are, I would appreciate it. Thanks! | Economics | explainlikeimfive | {
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"sometimes, stats like that *are* adjusted for the cost of living. the key phrase you want to look for is “purchasing power parity.” economists can look at a “basket” of commonly purchased items across many countries and come up with, for example, “the average citizen of country x lives on $10/day, at purchasing power parity.” when you see phrasing like that, then you know that you are being shown a sum of money that would buy, in america, whatever the equivalent amount of that currency, in that country, would buy. edit: and often, those stats are not adjusted. for example, if the reporter is trying to make a point about poverty in a country, he is not likely to adjust income for purchasing power parity, of course.",
"They don't buy as much of the things in their life. They don't buy food, they grow food. They don't buy clothes, they mend their ol clothes. You're comparing a consumer society to a agrarian society, which is a very different sort of thing."
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nezkzq | Why is the upper lip always less dry than the lower lip? | Biology | explainlikeimfive | {
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"Anyone else just touch their lips to test this?"
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nezqgm | Does air get thinner linearly with elevation? | Does air get thinner linearly with elevation? Is it as simple as for every x feet, the oxygen “thins” a certain amount, or is it more complicated? Other factors that can impact this as well is welcomed! Thank you to anyone in advance! | Physics | explainlikeimfive | {
"a_id": [
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"text": [
"Atmospheric pressure is not linear. It is logarithmic/exponential. This is because the increase of pressure is proportional to the air above it. So, the air above a layer plus the weight of that layer contributes to the pressure below that layer. Since that layer is at higher pressure than the ones above it, it contributes more weight than the ones above it."
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nf0tgw | why do tiny, inconsequential memories or thoughts stick with us for a lifetime, but other (often important ones) are hard to remember and rarely enter our brains? | Especially embarrassing moments, or times we simply found something out of place, but otherwise harmless. Compared to things we should remember, like when a bill is due, or another more serious thing or event. These are only examples, but I’m sure others can think of better ones. | Other | explainlikeimfive | {
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"Humans think in stories. What you’re describing as inconsequential memory is a story. Even if it’s a simple story like, I saw something out of place and couldn’t fix it and have lived with regret ever since. It’s a story. We can tell it and retell it. The stories we focus on reflect our values. They resurface in order to help us see something about ourselves or the space we occupy that we’d otherwise try to forget. The other memories like where we parked or when a bill is due gets severed from the stories to which they belong."
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nf1dng | how does narcan keep you alive in case of OD? | Biology | explainlikeimfive | {
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"The general idea: narcan (naloxone) binds more tightly to the same receptors opiates do, but doesn't act on those receptors. This inhibits the action of the opiates since there are few free receptor sites available, and the metabolism of the opiates continues as it normally does. (Also worth noting that naloxone is sometimes eliminated faster than the overdosed opiate, requiring supervision and possibly subsequent administrations of naloxone)"
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nf1h86 | Why do we have to work out our taxes if the Government already knows how much we owe? | Economics | explainlikeimfive | {
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"text": [
"The government *doesn't* know how much you owe. They don't know all the individual tax circumstances that relate to you, and even the pieces they *do* know, they want you to confirm. There are a ton of possible deductions and credits a person can be eligible for that never get reported to the IRS, including certain business, medical and school expenses. If you don't tell them about it, they'll just charge what they *think* you owe. A lot of people actually get a lot more money taken out of their paychecks each year for taxes than they actually owe, which is what tax refunds are for."
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nf21x3 | How does math explain matter, electrons and other stuff | Ive watched a physics girl video where she talked about antimatter, she said that it was discovered because it popped out from an equation of electron behavior. So how does one describe electron properties from maths? | Physics | explainlikeimfive | {
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"There's this thing called the Standard Model, which is pretty much the best description we have for the internal machinery of the universe. [This here]( URL_0 ) is a video explaining it very well by the fantastic Domain Of Science. You can kind of think of it as a big formula that you throw some numbers in and you can try and solve whatever comes out. Say that the magic numbers for an electron are (1, 3, -2). These numbers don't necessarily represent anything in the real world, but they're the \"magic numbers\" which describe electrons. If you were to then input the exact opposite numbers, you might still get a valid solution to the formula: a solution which describes positrons (the fancy particle physics word for an anti-electron).",
"It's not so much that math *explains* these things; it's used to *describe* them. Math is how you describe patterns and regularities in a quantitative way -- *any* sort of pattern. We notice patterns in nature, so we can construct mathematical rules to describe them. Based on those rules, you can derive other statements that should/could also be true. One of those things was that there should be particles with opposite properties of ones we already knew about.",
"Math has been the language of physics for a pretty long time - at least since Newton. This is not the only way to do physics, and plenty of other natural sciences have large portions of the theory that are not mathematical, but it seems particularly well suited for physics. Nobody really knows why. As for discovering things, what physicists are really doing is exploring all possible mathematical models for nature that are consistent with previous models and with new observations. Then they do the normal process of hypothesis testing of this new model to see if it's right. Many, many of them were wrong, but the successes are very neat. In the case of antimatter, we had equations that described the motions of slow electrons very well, but at high speeds it failed because special relativity was relevant. When we tried to incorporate that, we found that a natural extension to the existing equations looked like it had a new solution - an electron with the charge reversed. Sometimes these weird solutions are just accidents before the full theory is discovered, but in this case we tested it and found out these particles do exist. In some sense this isn't surprising. Somewhere out there the 'full' equations always existed. It's perfectly natural for us to get them slightly wrong at first, getting only an approximate solution for slow electrons that excluded positrons. But because they had some resemblance to the full equations, it wasn't long before we discovered those as well.",
"Math is the language of science. We use math to explain everything we observe and we use it to make predictions as well. In the simplest of terms. math is inputs and outputs.; 2 + 3 = 5. If we observe something and we see the inputs are 2 and 3, we know the result has to be 5. If we observe it and it's not 5, we know we're missing something on the other side of the equation. Perhaps one of the inputs was wrong or there's an input we don't know about yet. So we looked at electrons and modeled their behavior mathematically. We took all the inputs and the the output had something in it that we had never observed yet. Maybe the math was wrong, but maybe it was right and was it was describing something we just didn't know existed yet. We decided to look for it, and it turns out the math was right and correctly described something we had never discovered. We followed the math and looked for what was missing and discovered what the math said should exist."
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nf36y4 | Why do we only have a problem with sounds like people eating chips, when we're trying to concentrate? | I have a roommate and I swear to god everytime I try to sleep that's when he'll start chewing louder, I need to know why I get more conscious about it! | Other | explainlikeimfive | {
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"While our brains can do many different things at the same time, our attention tends to be more limited. Most people can only focus on one or two things at a time. While you are busy with something your attention will be with that task and your brain can filter out unimportant information like background noises. You can still hear it but it doesn't bother you as much. When you're trying to sleep, your brain is not generally as \"busy\" so if there is a noise it will take more of your attention and will sound louder/more annoying. Also when you sleep your house is probably quieter in general so any little noise will stand out more"
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nf3e08 | - why are hydrogen cars not more prominent? | Years ago I saw James May driving a hydrogen car in the USA. He was able to fill up and carry on driving on his way, so if the technology is there, why are there not more of them? | Chemistry | explainlikeimfive | {
"a_id": [
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"They're not particularly efficient or long-ranged, and they're a lot more prone to explosion than any other kind of car. So, there's not much interest in them. Electrics have them beat for efficiency and gas has them beat for convenience. Without interest, little to no infrastructure develops to support them, and so any small amount of interest that does form is squandered.",
"Hydrogen is a complete joke for a few reasons: - A fuel cell powertrain costs around $30k - Refilling a hydrogen car costs about $80 (to go 350 miles) - Refueling stations are only located in cities and special corridors. (Coast to coast drives STILL need a refueling truck) There's some stuff about fitting tanks in the car, storing hydrogen at fuel stations, and efficiency - but that's basically solved or no big deal. The big problems are all are economic - but for passenger cars EVs are superior and cheaper. (They have a hope at catching the heavy trucking industry, but it's not looking good - and asking CA and the USA for R & D grants or infrastructure - like they have been doing for the last 20 years - isn't gonna cut it.) People who claim it is a green fuel are swallowing oil company propaganda (most H is generated as a byproduct of petrochemical production) or banking on a miracle process from academia (people write papers about algae or some bs) that's never gonna scale. This largely hasn't changed in the last 10 years, too. Nobody is serious about hydrogen, it was all just \"pretend to be green but push gas cars\" hoping someone would gut the regulations before the industry has to retool for electric. Figures per googling - please correct me if I've overlooked something.",
"Hydrogen is inefficient. It can’t be captured naturally, it has to be extracted - and mostly as a byproduct of natural gas. It doesn’t have as clear a path to being truly green and electricity. It was a debate when battery technology want great. It’s improved a *ton*. Meanwhile we haven’t figured out how to get hydrogen more efficiently. So we have a winner."
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nf3ero | Why do we yawn/what is yawning. | Biology | explainlikeimfive | {
"a_id": [
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"text": [
"We don't know why we do it. Science hasn't come to a conclusion yet. There are three theories. 1) The deep inhaling is a way to cool your brain. The cool air when hits the roof of your nose and mouth acts to cool off the brain. This is the strongest theory we have so far. 2) The deep breath is to oxygenate your blood because your O2 is slightly low. Not enough to be a problem, but enough for your brain to respond. So it takes a deep breath. This is an older theory and it has weakening data. 3) It's an emotional signal to other humans that we're tired and vulnerable so we either need help or we are not able to work at the moment. This is partially to why yawning is contagious. Your social brain wants to be #relatable (sorry, not sorry) with others in your group."
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nf3uur | how do climbing plants “know” where to “reach” places where they can grab onto to grow up a surface? Ex: peas have those little green string “fingers” that they wrap around trellis in a garden. | Biology | explainlikeimfive | {
"a_id": [
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"They just slowly \"wiggle\" those arms until they hit something and then these twisting wiggling motions makes it wrap around. Will edit in a second if I find a timelapse Edit: [Here]( URL_0 ) It's basically like when it's dark and you're trying to reach for the lightswitch. Just try until you hit the target.",
"There are time lapse videos of vines growing where you can see that their tendrils wave around in a corkscrew-like pattern as they grow upward until they discover something to grab on to, kind of like how you feel around in the dark for walls and objects.",
"As the tendrils of these plans grow they rotate in progressively bigger circles until they make contact with something. After this point they will do their best to attack themselves to it and secure their grip. You should be able to find videos on YouTube of time lapses of plants doing this. I hope this helped!"
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nf47s2 | Why do we perceive infrared radiation as heat but not other wavelengths? | Physics | explainlikeimfive | {
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"We don't. We experience all wavelengths as heat. IR just happens to be the range that most of the heat is in, at the temperature range humans are exposed to. This is in part because IR is a huge range of frequencies, spanning all the way from radio-like far-IR to visible-like near-IR.",
"Infrared is a color, heat is detected based on intensity not color. Point the bulb of a remote control at your hand and change the channel. Your tv and your phone camera will see the infrared light, but you won’t feel a thing. If someone were to dangerously point a 2 watt visible blue laser at your skin you would feel the heat. As for why infrared is associated with heat, a hot thing always gives off light, the hotter something is the “bluer” the light is. Things that are merely warm are giving off light that is infrared. Make it hotter and the light is so blue it enters a visible spectrum, IE it becomes glowing red hot. If it was hotter it might become white hot. Welders deal with things so hot it might give them sunburns because it so hot it’s ultra violet.",
"It's not that we perceive only infrared radiation as heat, it's that most objects we encounter radiate most of their thermal energy in the infrared portion of the electromagnetic spectrum. All objects above absolute zero emit energy in the form of electromagnetic radiation. We call this blackbody radiation. The part of the spectrum that objects will emit most of their radiation in is based on their temperature. [Check out this nifty tool]( URL_0 ). That curve is called a blackbody spectrum. You can see the if you slide the temperature up, the peak of the curve, meaning the bulk of the energy, gets emitted as higher frequency radiation like ultraviolet, and if you slide it down, the bulk of the energy is emitted at lower frequency radiation like infrared. You emit infrared radiation because you're not hot enough to emit visible light. The sun is much hotter so it emits most if its energy as visible light.",
"That’s not the case, microwaves heat food up with well, microwaves, and visible light can produce quite a bit of heat, that’s how lasers can set stuff on fire, and those works on one specific wavelength Any wavelength is heat, just it so happens that hot stuff emits mostly infrared radiation which we feel as heat and nothing else because it’s invisible",
"Because the infrared (IR) wavelengths are easily absorbed by the human body --- specifically, it makes the molecules in our body vibrate. The absorption of the wavelength and corresponding **vibration** is what we feel as heat. The lower frequency waves, like radio waves, just pass through; they don't resonate with anything in our body. So does most visible light; IR is in a sweet-spot for absorption by most of the human body. We do absorb some visible light though, in blood and pigment, e.g., like melanin, the pigment in our skin that also absorbs UV light. The way light is absorbed by pigment and blood and reflected back is what determines our skin color and eye color ([source]( URL_1 )). However, even for things like lightbulbs that emit a lot of visible light, there is *way* more infrared light emitted, usually more than 50% infrared light compared to visible light ([source]( URL_0 )), so the IR radiation is why they feel hot. LEDs, however, are almost *entirely* visible light. This is why an incandescent bulb feels much hotter than an LED. UV light we *do* absorb, but it's so high energy it doesn't just vibrate our molecules; it damages and kills them, giving us sunburns and tans and sometimes skin cancer. But it's vibrating at too *high* of a frequency to make us feel heat. Think of a dog whistle: a dog's ears can hear it, but we can't because the sound is too high frequency. We don't feel UV as heat because it's too high frequency. X-rays, even higher energy than UV rays, pass through a lot of parts of the human body, with a little absorption by muscle and fat but a *lot* of absorption by bones, which is why we can use them for imaging things inside our bodies. **tl;dr:** IR light is the goldilocks medium of wavelengths: not too fast, not too slow, but juuust right to warm us up (by vibrating our molecules)."
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nf4tj4 | Can you travel to a particular coordinate in space? | I'm wondering how coordinates work in space and if it's possible to travel to a particular location in space. Is it possible to exchange coordinates and meet at an exact location in open space, similar to GPS on earth? | Other | explainlikeimfive | {
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"Theoretically, sure, but it's not quite the same. The surface of the Earth is 2-dimensional, but space is 3 dimensional, so you have to specify 3 coordinates, not just 2. On Earth, we use east/west and north/south, and that gives you a fixed location. In space, we project an imaginary sphere around the earth and use coordinates called declination which tells us the angle above or below the equator, and right ascension, which tells us the the angular distance measured eastward from the equator at the vernal equinox. Those 2 things only give you a direction, but space is 3 dimensional, so you need a 3rd coordinate as well: distance. If you give a right ascention, declination, and distance, you can give \"directions\" to any celestial object. It's also important to remember that everything in space is moving, and coordinates are only meaningful from a fixed point of reference, so depending on where you are and where you're going, you may need to choose different reference points. Also, space travel doesn't really work like that so it's not useful for that purpose. It's more more locating and tracking celestial objects, not as a means of navigation. We have other ways of navigating in space."
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11
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nf5fea | Why do Windows' diagnostic procedures never work? | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"These programs look for some of the most common types of problems and attempt the common solutions for them. Unfortunately most people don't have these problems, they have other less common problems. Also the known common problems tend to become less common as developers become aware of them so these programs are even less useful. Occasionally they do end up solving a problem though. I am honestly surprised when they do, but it happens.",
"Funnily enough I have found exactly one windows diagnosis that worked. At work people kept getting booted off of the wifi. I used windows diagnosis as a last resort because I was so frustrated, and it updated some settings and everything worked immediately."
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nf5s6d | How does a phone restart? What part makes it turn on by itself? | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"It's never fully off. It can almost completely turn off, but it doesn't go all the way. Take a look at the power button. It's not like your light switch on your wall that physically disconnects the wires. With this type of switch, the wires are always connected, and when the phone is \"off\", it's still on enough to monitor if the power button has been pressed. It's also why when your phone is \"on\", pressing the power button doesn't instantly cut power to your phone.",
"One of the computer chips in a phone is the power management IC (PMIC). The PMIC turns devices on and off, regulates voltages, keeps an eye on the battery, and usually handles reset. The main processor can tell the PMIC, \"restart me\" or \"power off\". The PMIC handles turning power off, monitoring standby devices, resetting and restarting. If the battery is too discharged, the PMIC stops too. When the battery is charged a little, the PMIC is the first chip to be energized and can delay power on until the battery has enough energy to boot the main processor."
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nf6hvh | What the main goal of stoicism. | Other | explainlikeimfive | {
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"As per the Enchiridion, the main goal of Stoicism is to not experience unnecessary emotions and to remain levelheaded, rational and focused on proper living. The idea is that humans were given the capacity for rationality and proper living by their creator, so it is inappropriate to act irrationally or to live improperly. The early Stoics also believed in predestination and the idea that you can't escape from suffering or hardship.",
"The goal of stoicism is to maintain control of your emotions despite being put in situations that are emotionally draining. The goal is to have a more peaceful life by accepting that most things that are bad around you can’t easily be changed. Also, I highly recommend that you watch this lecture: URL_0",
"So the normal condition of humans is cyclical - we are either happy or sad (different degrees of these emotions). This leads us to experience life as highs & lows. Many (***almost*** all) of the highs and lows are \"externally anchored\" - meaning something happens outside in the environment and we create an emotional response to it - by naming that event as good or bad (favourable or unfavourable). This leads to us to \"giving our internal remote control\" to others - where they consciously or unconsciously keep pressing buttons and we keep emotionally dancing - up or down. Stoicism is a way of life where you reclaim your remote control back. So now your emotional state is not at the mercy of others and circumstances. Now **you** choose, to what event you will respond to and to what intensity. Being in this balanced state will make us live purposefully (and not be tossed about by the inherent fluctuations of life). The Stoic Way of Life - also focuses on acceptance of whatever is happening around us / to us. Out of total \"non judgemental\" acceptance of all that is happening - emerges a way to adapt to or change it - without losing our balanced state of being. Stoicism is not being \"numb\" - as it is misunderstood often. It is about being aware and conscious - and choosing how you experience life."
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nf6iy8 | - How do companies make money when we waste our time on their apps/websites? | I recently watched a documentary on how social media sites try to keep you on the platform and try to lure you in when you are not on the platform. How exactly do they make money when we waste our time on these platforms? These days it might have something to do with ads (which I still don't entirely understand) but what about before the ad era? When these platforms first took off, how did they make money when we don't actually pay anything to use these platforms other than our time? | Technology | explainlikeimfive | {
"a_id": [
"gyjurut",
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"text": [
"Before the ad era there was no social media. Its realy only advertising or selling advertising spots on the website to others to be more precise. Facebook knows alot about you, like where you live, your relationship status and your education. This is why they offer the best quality to any company who wants to advertise. Only facebook is able to display the advertising for a fertility clinic to young woman who are in a relatonship since a minimum amount of time. Thats why advertising on facebook or other social media is so much more worth compared to a street sign. And facebook does do just that: selling space on your devices screen in real time based on what facebook knows about you.",
"Targeted advertising. Go back to the days of newspapers, and you would spend money to put out an ad. Let's say it cost $100, and you knew that 1,000 people bought the newspaper. You were paying $0.10 per impression. However, if you had a very narrow focused ad that only really mattered to 50 people, you're wasting 950 impressions. Your cost per effective impression is $2.00. But what if you could deliver your ad to only the 50 people that you want? Would you pay $50 for those 50 ads? It's less than your $100 otherwise, and you don't really care if you don't get those 950 worthless ad impressions. This is a win for you. but it's also a win for the newspaper. They still have 950 prints to sell a different advertisement on. If it's $1 per ad, they can make $1,000 from that ad slot instead of the $100 you originally paid. This is how these websites make so much money. They have collected so much information on you that they can sell focused advertisements. Focused advertisements cost so much more than regular advertisements. Rather than ads help reduce the cost of a website like they did in the '90s and early '00s, they're a considerable source of income these days.",
"Everything you do on social media is tracked. That data is sold to companies for targeted adds. Didn't click anything and just looked at a post? They tracked how long you looked. Even just talking around your phone can bring up suggested adds. We live in 1984 already. Get comfy."
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nf7frs | personality disorders | Other | explainlikeimfive | {
"a_id": [
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"text": [
"My best litmus test for personality disorders is: \"If you removed this disorder from someone, is it clear \\_who\\_ that person would be? \" For example someone with autism. If you could magically 'cure' the autisim from someone, who would they be? It's tempting to just imagine obvious symptoms not being there but when we think about it, it can be hard to see where the 'disorder' begins and when the 'true them' begins. They might like cars, this could be a hyper fixation and a symptom of autism. However, people without autism can like cars and get really involved in a hobby. So would this hypothetical autism free version of a person like cars or not? How much would they like them? Autistic people tend to like order. But not all people who like order are autistic, so if we could remove the autism from a person how orderly would they be? There's no real clear answer to these questions. Having a personality disorder means the disorder is deeply intertwined with your personality and identity. There is no 'true them' without the disorder, if they didn't have the disorder they'd likely have another personality and at that point couldn't really be called the same person. Compare this to something like epilepsy, still a disorder, but we have a much easier time drawing a line between what is a symptom and what is their personality.",
"Mainstream and popular science media love to pretend we know enough about the brain to answer such a question. We don't. Especially not for something so complex and multi-faceted as \"personality\". They are called \"personality\" disorders but in reality they are more focused on interpersonal relationships and dysfunctional ways of behaving inside those. Common for all of them is that there is some pattern of behavior that causes problems in their social lives.",
"You've got as much idea as most people. It's a very contentious issue. I did a module on the philosophy of psychology, and it really gets you to question what we know and what we don't know about what is \"normal\". A lot of psychological issues are comorbid as well, so if you have one issue there is a chance that you also have another issue. Underpinning all this is a whole philosophical argument of mind vs body. Is a personality disorder a disorder of the mind or body?, and then where does the mind start and the body end.",
"Personality disorder refers to a cluster of symptoms, primary characteristics are emotional dysregulation, fragile self-image and interpersonal difficulties. These symptoms are the result of significant trauma (usually during early life) and relate to traumas impact on neural development; the brains of people with personality disorder/who experience trauma in early life tend to have overactive amygdala, and often perceive threats where there are none."
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nf7kn5 | how wildlife documentary cameraguys does not get seen(or smelled) by the wildlife (e.g. tigers and lions ) when they hunt and probably they senses are at the highest level? I mean, they watch them probably for hours or days to get the right shot and the animals seem not to care at all. | Other | explainlikeimfive | {
"a_id": [
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"text": [
"Several reasons: Exposure to people. Not many places are still truly wild. A lot of wild life reserves can have a lot of people moving through. Zoom lenses. Just because the footage looks like they are 30 feet away doesn't mean they aren't closer to a thousand. Downwind placement. Distance + wind direction = less likely to be noticed. Long term exposure. A lot of wild life documentarians will spend a long time getting their target accustomed to their presence before they get the footage they seek. Basically weeks or months of the animals being skittish until they relax and trust the person isn't a threat. Remote filming. Motion sensors on the equipment to activate it. Person stays away for days at a time to prevent fresh scent being laid down.",
"Animals are likely very far away when being filmed, so much so that humans are barely a bother to them. This is achieved with the use of a very powerful telescopic camera lense, like the ones used to get extremely clear pictures of the moon but less powerful."
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nf7n53 | If you had a vocal cord transplant, would your voice sound like you or the donor? | Biology | explainlikeimfive | {
"a_id": [
"gyk0jp1"
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"text": [
"Your voice comes from a combination of the unique structure of your own vocal chords and your specific way of breathing, shaping your mouth, throat, etc. A vocal chord transplant would not automatically sound like the donor's voice but it might sound different from your normal voice depending on how pronounced the differences in structure of the donor's chords and yours are. Any damage or degradation to the chords from the transplant surgery or etc. would also have an effect. On the other hand you're likely to adjust your inflections to match closer to the sound of your original speech, whether consciously or subconsciously."
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nf7nt1 | How are wildlife video's shot that too in ultra high HD? How does a cameraman or a drone get close to animals without startling them. How do they film an exact moment of an event happening like a mating dance or a fight between animals | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"Firstly: It takes *months*. Secondly: Unless the camera man is following a particular pack, most documentaries with cut together footage of different animals and \"tell the story\" of one very interesting one.",
"> How are wildlife video's shot that too in ultra high HD? You bring ultra high HD equipment > How does a cameraman or a drone get close to animals without startling them. You don't get close. You use really powerful lenses, like 15 thousand dollar ones. Source: URL_0 lens: URL_1 picture of the lens: URL_2 You also don't get close to them. You pick a spot, get some camo, stay there for a while without shower (so your soap smell won't startle the animals), and then wait until the animals get close to you. That will take a long-long time. That's why you have to be smart about it, and pick up strategic locations where you suspect that animals might pass by. > How do they film an exact moment of an event happening like a mating dance or a fight between animals You film the entire time. For hours and hours. And once a while, you get lucky.",
"There's lots of little and big tricks that the Nature Doc guys use. If you watch the end of any of the more recent David Attenborough programs like Blue Planet II they show you some behind the scenes stuff. But your main answer is lots of patience and HUGE lenses on the cameras. You're talking between 400mm to 800mm and these lenses can weigh up to 10 lbs. You can get a lot of shots done if you stick to watering hole times at predawn / dusk. If you're a decent distance away with a large lens you have about half an hour of intense activity just before sunrise and the best light as well. They have started using drones but their use is limited because animals do react to the drones - so you're talking pretty heavy duty drones with again quite significant lenses on staying at a decent distance away."
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"https://i.ytimg.com/vi/iRUJwtVLrnc/maxresdefault.jpg"
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nf8h62 | Do plants have unique DNA like humans? For example, if there were two gardenia bushes and a flower fell to the ground, could it be determined which one it came from like genetic testing etc on humans? | Biology | explainlikeimfive | {
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"Sort of? Plants reproduce sexually like humans and animals, that is what seeds and pollen and stuff do and when they do that they they have different DNA. plants also have a thing that animals don't, where you can slice a part off a plant and if you plant it carefully it will keep living and growing into a new plant pretty easy. People that make fruit and flowers and stuff love this, you can get a nice plant growing then slice parts off it forever and ever to make exact identical copies. So a lot of stuff like flowers and fruit are just 'cuttings' of other identical plants. Like we don't ever plant banana seeds, there is just one banana plant that everyone has copied over and over for decades. So some sorts of flowers, yeah, you could find the bush, but some are grafts or cuttings and are basically endless natural clones.",
"[They do, and it was used to solve a murder case]( URL_0 ). A guy was suspected of having murdered a woman. There was a particular type of tree growing where her body was discovered, and seed pods from the same type of tree were found in the bed of his truck. Investigators got the DNA fingerprint of the seed pod and were able to match it to the tree growing at the crime scene, proving he had been there.",
"It depends on how the plant was pollinated. Some plants pollinate themselves in which case the two plants would have the same DNA. If the plant was pollinated by different plants then the offspring of that plant will have unique DNA",
"Yes. In fact, flowers are part of how plants have \"sex\". Pollen can be thought of as a plant's sperm and when it's moved from flower to flower it allows for genes from one plant to mix with another. Even fruits like oranges are from humans selectively breeding trees.",
"Plants like Gardenia can be and are cultivated from seeds or cuttings. Gardenias grown from cuttings from the same plant would have identical DNA to both their \"siblings\" and the \"parent\". Human DNA profiling is a science that has evolve over 70 years. It doesn't sequence, look and compare the whole of the DNA. Instead with the Short Tandem Repeats (STR) method it looks at the specific length of STRs at particular genetic loci - places in the DNA that we've worked out are good to use for identification. Plants and other animals on the other hand we haven't developed the ready to go CSI DNA profiling for yet - the techniques that we have for plants are designed to detect mutations or other undesirable genes and not for DNA matching. It's possible but don't expect a ready to go test that you can ship the samples off to for 48 hour return analysis.",
"Of course they go. All living things have unique DNA. Although in case of plants it’s somewhat harder because they often can have natural clones and are often cloned in gardens. It’s very easy - for many plants if you cut off a branch and stick it into ground it will take root and make a clone of the original plant. If something like that happened then they would have identical DNA and genetically indistinguishable. If both plants grew naturally from seed though, then yes, you could identify them by DNA.",
"Plants have DNA the same way that humans and other animals have DNA. And they do reproduce sexually using flowers, pollen and seeds. So you can analyze the plants DNA to figure out which plant a flower comes from. However plants can also reproduce asexually. This is done by taking one limb of a plant and then plant it in the ground. It is able to grow a completely new plant from this cut off limb. In this case the new plant will have the same DNA as the parent plant. So you can not determine which of the two plants a flower came from using the same techniques. Plants that are close together could have been planted like that by humans or it could be a result of natural asexual reproduction at some point.",
"All living things have DNA. Observation of generations of cross-bred plants are actually how the first scientific studies of inherited phenotypes (i.e. visible genetic traits like size, color, and so on) were conducted by Gregor Mendel, paving the way for the study of genetics.",
"You have a unique set of DNA from other humans and the same concept applies to plants even of the same subspecies. However, there are exceptions to this with plants. Consider this: If you had a skin graft taken to regrow your ear, your DNA would match a sample taken from that graft as you are its original source. Unless you had another graft taken, no other skin graft would contain your DNA, even if they appear very similar. The same applies to plant \"cuttings\", the original plants all have slightly different DNA but the cuttings themselves would have the same DNA as their \"host\" plants or parent plants. It's almost a form of cloning, the DNA (cutting X) is identical to that of the original source (plant X) but a cutting (cutting Y) from another plant (plant Y) of the same subspecies would have slightly different DNA than cutting X or plant X. So, yes and no, it depends (as seen above)",
"As long as the two gardenias were of separate species you could do so easily. If they were from the same species then it would be difficult. If they were propagated from cuttings or tissue culture using the same mother plant then no; those are genetically identical. Tissue culture has been all the rage for the last ten years or so. They are clones produced in a laboratory. Go to Home Depot or any garden center and notice how some plants are in fancy colored pots with Southern Living or something similar on them; they cost more than the generic black potted plants because they are patented and trademarked. My nursery paid big bucks for rights to grow them but we have to buy the liners from the patent holder and sell them in the fancy pots that cost three times what a normal pot does. Of course we wholesale them for three times what we sell our generic species for also. Plants propagated from cuttings will revert over generations so you can genetically identify them. Years ago Monrovia found a plumbago that bloomed deep blue, almost purple; they took cuttings from it and trademarked it as 'Royal Cape'. Of course all us other nurseries bought some, took cuttings and sold them as 'Imperial Blue' Monrovia could not patent their plant because it was genetically identical to the rest of the plumbagos, so they trademarked the name. If you take a cutting off of an original imperial blue and then take a cutting off that when it matures your third generation will have reverted back to a plain old plumbago. You have to take the cuttings off the original stock plant. Many sports or cultivars will revert back true to species. Sorry if long here, plants are kind of my thing."
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nf8rsk | - When you “see stars” what is actually happening? | Biology | explainlikeimfive | {
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"Blood flow is cut off momentarily from the brain as the momentum of standing up pulls slow-moving blood downwards. Your brain understandably freaks out, and the sensory areas go a bit haywire in the process which can lead to sensory hallucinations such as seeing the room spinning, bright miscolored splotches or 'stars', vertigo, and even fainting if the area of your brain that controls your motor functions loses blood flow long enough."
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nf8w46 | Why does a clean floor get sticky if it is not cleaned for a while? | Other | explainlikeimfive | {
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"A clean floor can be sticky if there is enough condensation formed on the surface from high humidity",
"What kind of surface is the floor? Because it depends",
"Some cleaners will leave behind a sticky residue when they dry, especially if over concentrated, which a lot of people tend to do."
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nf9ej4 | Why can't single-use plastics just be mixed together, melted down, and used to make any other plastic products? | Chemistry | explainlikeimfive | {
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"Polymer Chemist here. Plastics which are single use plastics are normally commodity polymers such as Polyethylene, Polypropylene, PET, Polystyrene, PVC etc. Problem is that these different types of plastics cannot be mixed together because they tend to melt at different temperatures and also if you try to melt them together they all degrade and you are left with nothing but mess that is useless. Therefore, unless these plastics must be segregated based on their recycling class (the small triangle at the bottom of all recycling bottles for examples) and then melted together only with plastics which match same class you get useful recycling out of them.",
"Firstly plastic is not all a single chemical. There are thousands of different chemicals which can all be described as plastic. They all have different properties and do not work well when mixed together. It is hard to sort plastic as well since while they have different properties these are not easy to distinguish. There are some expensive big robots which use a number of different techniques to sort plastics but these are not common as they can be quite expensive investments. Another huge problem with sorting plastic is that most single use plastic products are composed of multiple different types of plastic and even other materials. It is very hard to seperate these materials from each other to sort them individually. Just imagine a plastic bottle which have a different type of platic for its cap and then the label is made up of yet another type of plastic with a forth type of plastic used for the printing on the label. And then yet another material is used to glue the label onto the bottle. That makes it almost impossible to recycle the bottle. And it is not just different types of plastic but you see a lot of packages combining metal foil, plastic and paper to get the properties they want. And you do not want metal foil or paper in your plastic that you want to recycle. You might just bearly accept the color pigments that is in the plastic as it is. And then another issue is that some plastics can not actually be melted down and recycled. Their melting temperature is higher then their self-combustion temperature. So even if you put it in a vaccuum and heat it up you will just end up with charcoal instead of molten plastic. The way these plastic products are made in the first place is through chemical reactions for exapmple by mixing two compounts together which will harden into plastic or by heating up a compound, sumbiting it to UV radiation or just give it a nucleation point. Even those plastics that can be remelted will often degrade a bit every time you do this so recycled plastic have a worse quality then freshly made plastic.",
"Plastics are a material class, this contains many different kinds of plastics. The same way that metals contain iron, aluminium, copper, titanium, and others. You *could* mix them all together and make something out of it, but you would have no idea what it would be and you wouldn't know its properties (strength, colour, melting point) so cannot make anything specific or useful. There are many other reasons such as: * Making sure you have plastics and only plastics (no contamination). * Required properties for a product (such as meeting food safety standards, resistant to chemical attack, see through or not). * Cost - it would be expensive to do. It is not very useful or practical, basically.",
"It's like saying why can't we recycle random bits of aluminum, steel, and copper together into one big metal product. You will not get a good product with known properties in the end, just some strange slag of metal that may or may not be suitable for any one purpose. In practice it is easier to separate aluminum, steel, and copper due to widely varying melting points, but not so much with plastics.",
"Singe use is not about the plastic but abut the product that is designed for a single use and later disposal. Plastic is a type of material and the properties of all are not the same. So you need to sort them and that the impractical for small plastic products. Lost of single use plastic produce are recycled. Plastic soda bottle are single use plastic produce and they are the most recycled plastic product."
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nfa8hq | Why is it harder to breath when facing into the wind (I.e while driving and you stick your head out the window) | Biology | explainlikeimfive | {
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"Bernoulli's Principle. Basically, this says that the faster the air is moving, the lower its pressure. Since the fast-moving air you've stuck your head into is lower pressure, you need to breathe in deeper to get the same volume of air into your lungs.",
"Breathing relies on pressure differences. Gas molecules automatically move to create the same pressure across the container (as a very simple explanation). If you make your lungs lower pressure than the external air, then air rushes into your lungs until your lungs are the same pressure as the outside air. If you make your lungs higher pressure, then air rushes out of your lungs until they're the same pressure as the outside air. We've evolved to do this in air pressures that are around those found at sea level on a calm day, give or take. When we're in lower pressure air, breathing in doesn't create as much of a pressure difference, so less air enters the lungs and air enters the lungs more slowly. High altitudes are hard to breathe at because air pressure decreases as you get further away from Earth's centre of gravity (ie, by going up), and wind is hard to breathe in because wind is lower pressure than calm air.",
"it's called: a laryngospasm, where the vocal chords spasm and seal that pathway. something is being forced into your airways and your body doesn't know if it's water or air"
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nfbdd7 | why do people (in general) become less tolerant to noise (clubs, crowds, kids, etc) as we grow old? | Other | explainlikeimfive | {
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"I have a theory: 1. Hearing loss occurs in specific frequencies. 2. Brain compensates withneuroplasticity, rewires pathways by increasing linkages to expand or speed up anything related to audio pattern recognition to return to as close to a \"normal\" response speed as it can. 3. Loud noises and unwanted sounds stimulate these compensationaly-increased pathways, but since the brain is not rewarded with any recognizable pattern, the magnified stimulation is proportionately annoying. 4. This ultimately leads to a conditioned response of hypersensitivity to noise.",
"My very simple (and amateur) take is that when we're young we tend to prefer activity, excitement, new experiences, etc, and as we get older we prefer stability, peace, and quiet. Not sure if there's something more going on with physiology or not?"
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nfbkmu | How are several lower quality photos of the same object use to make a high resolution composite picture? | Technology | explainlikeimfive | {
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"With cameras it’s all about the amount of information you can give them to work with. Having several images allows the cameras processor to stack them and use data from all of them to make filling in “missing” data (areas with less detail) more accurate than with just a single image.",
"This uses the fact that your different low resolution images are slightly misaligned. Images are composed of pixel and each pixel will show basically the average colour of what was there. Now let say you are taking a picture of a black line on a white background, and the line is half a pixel width. You pixel will be grey. But if you have another image and you able to tell this picture is half a pixel upward. Now you have information on the same area but half a pixel shifted. And when looking at this new picture, you notice that the pixel that covers the upper half of the old grey pixel is white. Now you know that on the grey pixel, all the grey you have seen is actually due to the lower half. It is roughly the same principle you apply with a bit more complex mathematical formulas. There is nothing magic though: if you want to double your resolution, meaning multiply the number of pixels by 4, you will need at least 4 images. And because they won't be perfectly misaligned, you would need actually more. You also have other techniques of Super-Resolution that do not do mathematically correct operations, but rather guess the content. Much like when you seen a low resolution image of a face, you can imagine what the eyes will look like. It won't be perfectly accurate but in some applications will be good enough."
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nfbmxz | How would a society without work even function | Other | explainlikeimfive | {
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"Could you get more specific? Like it's a big difference if we all just stopped working now (because then it wouldn't take long until billions start starving) or if we replace (almost) all work by machines in the future.",
"Have you watched Wall-E? URL_0 But seriously our use of robotics increases every day and so our percentage work force shrinks and hopefully our working hours will start shrinking too at some point - leaving more time for exercise and studies and hopefully not just leisure. But I doubt we'll ever reach the point of having society without work at all - if computers/A.I.s/robots could get that sophisticated then why would they need humans anymore? They'd eventually overthrow us."
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nfbozu | How do we grow? Do the new cells just pop in between old cells or what? | Biology | explainlikeimfive | {
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"We don't know “exactly”, but generally speaking, we all have cells in our body that can divide, thus make more cells, in adults not leading to growth in height, but replacing the cells that have died off. In children adding more cells will result in growth in height, and body width, the cells or the organs respecting the borders of the organ (cancer growths don’t respect these borders), how they grow is precisely regulated by many substances, growth factors etc. The fine balance results in a healthy bigger child, and eventually a healthy adult. See [Physical Growth of Infants and Children - Children's Health Issues - Merck Manuals Consumer Version]( URL_0 )",
"The old cells grow in size until the split into two new cells which then continue to grow in size and split into even more cells."
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nfbq6b | Why do water temperatures feel different before, during, and after swimming? | You get in the pool and the water feels cold. Then you get used to it and it no longer feels cold. Then it’s time to get out of the pool and it feels warmer in the water than it does outside. I don’t understand. | Biology | explainlikeimfive | {
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"Your body can only sense the difference in temperature, not the actual temperature like a thermometer. You can try this out by having 3 bowls containing warm, room temperature, and cold water. Put one hand in the warm water and your other in the cold water for about a minute. Then move your hands into the room temperature water. The hand in warm water will feel cold while the hand cold water will feel warm despite the fact that your hands are in water of the same temperature. The same happens at the pool. Your skin temperature is normally higher than the water temperature. When you first dip in, your skin feels the huge temperature difference and it feels cold! But over time, the skin's temperature adjusts to the water's temperature and you don't feel any difference. You still have to move around and generate more heat from playing and swimming. Remaining stationary in cool water can lead to hypothermia as water can remove heat faster than air. Getting out of the water feels cold because of evaporative cooling, the same effect where sweat cools you down. The pool water on your skin starts to vaporize and carry heat with it, cooling the skin. If you get back in the water, it stops this effect, making you feel warmer. Drying yourself off also stops the evaporative cooling and can also make you feel warm despite no changes in air temperature.",
"Your sense of temperature is actually how quickly thermal energy is leaving (or entering) your body. Water wicks away heat much faster than air. Water that is the same temperature as the air will pull thermal energy away much faster. This is why it feels cold when you get in a pool. The next thing is evaporation. Evaporation takes a lot of energy. When the water that is on your skin after you leave the pool evaporates, it needs an extra bit of energy to do so. This basically increases the amount of heat it can pull from you, furthering that wicking effect. As the water evaporates off, it consumes a lot of heat from your body to do so."
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nfbsdm | Why is there a chip shortage? Can't they just make more chip factories? | Economics | explainlikeimfive | {
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"Demand increased too fast and unexpectedly. Building new chip production lines takes **at least** 2 years, so unless demand goes down again (unlikely) the shortage will last for a while until they can catch up. Chip production is a highly complex process with many substeps that all need very specialized equipment. You propably won't find that many companies that build silicon crystal crucibles so everyone trying to expand at once further slows it.",
"> Why is there a chip shortage? Covid significantly increased the demand for many electronics that used chip. In addition, supply chain problems and general covid restrictions have made making chips slightly more difficult to produce and distribute/ship, which is pretty much on par with many other goods during the pandemic, its been a bit harder to make things and get them where they need to go. > Can't they just make more chip factories? Yes, and they are, but it takes a long time to build them, multiple years at a minimum. Actually they are pretty much nonstop always making more and newer chip factories, before, during and after covid. Sometimes for making newer chips its even cheaper just to build a new plant than to upgrade old ones. Chip factories are nearly always going through new factories or major upgrades and chip manufacturing is a strongly growing business."
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nfcdqe | Why can we move our fingers freely yet our toes have limited movement? | Biology | explainlikeimfive | {
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"Over the millennia human feet have evolved to take all the pressure off our hands and make us incredible endurance athletes. They handle all the walking so you never have to “knuckle walk” like the other great apes - your hands are always free. They’re highly efficient at this and you spend very little energy walking or jogging. While we’re not the fastest animal out there, we can pursue another animal relentlessly and barely break a sweat. All this required massive specialization in the foot bones and musculature. All the fine motor muscle is gone, replaced with strong tendons to recoil on every step. Elongated metatarsal bones to amplify the leverage and short toe bones to drive off the ground without flexing. Imagine trying to actually run if you had hand-like feet. It wouldn’t work - the fingers are too spindly and weak to kick off with every step. Apes with more hand-like feet can’t run on two legs, they have to charge on all fours. They’re pretty fast like that, but they can’t carry a spear.",
"I don’t know about you, but I can move my toes pretty freely. Now since they are a lot smaller than the fingers they don’t have as wide of range of movement.",
"We no longer have an opposable toe! We have the same functionality but nothing for that functionality to work against. Instead we have improved mobility and efficiency."
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nfdaz6 | How is radioactive dust detected? | Physics | explainlikeimfive | {
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"It's radioactive, that's how. When it gets near a radiation detector, the particles coming from it hit the detector, increasing the number of detection events it has per second from the ambient value.",
"The most effective way is with a Geiger counter. This is a device that can detect ionizing radiation that interacts with it. It does not detect the radioactive dust directly but you can figure out where the radiation comes from through a few different techniques so that you can detect if it is from dust or other sources such as rocks or gasses. If the concentration is too low to be easily detectable you may need to leave the Geiger counter running for a longer time and measure the accumulated radiation. Or you can collect the dust with some sort of filter or collection plate and then measure the radiation of this."
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nfdiym | How does shoving fingers down your throat make you puke? | Biology | explainlikeimfive | {
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"It activates what's called your \"gag reflex\". Only three things are supposed to go down your throat...air, liquid, and chewed (i.e. soft) food. Anything else isn't supposed to be there and you have a reflex that causes you to gag, then throw up, if something solid-ish goes past the back of your throat. This prevents you from trying to swallow things that won't go down your throat and could block your throat (killing you). Your throat isn't smart enough to tell the difference between your fingers and some other solid, so you can \"trick\" your gag reflex with your fingers."
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nfecnt | What is happening in your stomach when you’re hungry that makes that grumbling noise? | Biology | explainlikeimfive | {
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"Gas and liquids are constantly moving around in your gut and is a normal byproduct of consuming food/liquid and the digestive process. When you are hungry your brain tells your digestive tract to prepare for an immanent meal and this signal releases hormones that cause parts of the digestive tract to contract, pushing the gas and liquid through your intestines. That is what you're hearing. You can actually hear this pretty much constantly with a stethoscope to your gut but it's not as audible/loud all the time as compared when you're hungry or have an upset stomach."
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nfewc6 | - Do flames / fire follow a predictable path when they move freely in the air? | Does a naked flame follow any logical movement? What I'm talking about is how you can watch a lit candle or bonfire and observe the flames moving freely in the air. The flames stay "attached" to whatever is burning (the wick, wood, etc) but they sway around in the air. I'm wondering if there's any way to predict a flame's movement or is it totally random how it flits around in the air? | Chemistry | explainlikeimfive | {
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"In theory if you have complete data of all the air currents, pressures and temperature in the room and whatever is burning you can calculate this perfectly. The problem is that there is no easy way of collecting all this data. And if your measurements are off by a bit you may end up with completely wrong results. Especially in the sharp air interfaces generated by the heat which is responsible to generate the turbulence. In these interfaces any tiny curve will get amplified into large swerves which is what causes the flame to move back and forth. So while it is possible in theory to calculate all this in practice it is impossible.",
"It’s not random, but it’s not predictable either. The flame is dancing around with the air currents around it. It’s also directly impacting the currents by consuming cool oxygen and generating superheated gases. In theory, you could model the gases in this system and predict how it will evolve. In practice, this is an impossible task. The turbulent air currents are an enormously complicated system, and this in turn changes the reaction rate and profile of the combustion. That change then feeds back into the turbulence, so even very tiny changes are quickly amplified through the feedback loop. It would take a supercomputer a very long time to model even a few seconds of this sort of system. Your model may be roughly accurate for a second or two, but small variance at the molecular scale will quickly build up errors."
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nffj16 | Why do public companies need to publish their figures and give accurate predictions for the next year? | It just seems like a lot of risk, so why can’t The company just stay private? 🙄 | Economics | explainlikeimfive | {
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"The company chose to go public. No company is forced to go public. The owners of the company make a conscious and complicated choice to opt-in to being a public company and all the good and bad associated with it However, once you are a public company, the government mandates some extremely specific financial reporting requirements to allow you to be a publicly traded company. A public company can also return to being private, and this is not uncommon, but it can be difficult and expensive to do so (more or less, someone has to buy out all the public shares of the company, the most common version of this is in mergers and acquisitions, say if a public company gets bought out by a private one, the old public company will become part of the private company, so the public company ceases to exist) On \"predictions\" those are called \"forward looking statements\" and while companies provide them, they are not meant to be viewed as real or truthful, just predictions. Companies try to predict their future, but they are not necessarily bound to those predictions or actions. Most financial predictions are not done by the companies themselves, but by outside analysts",
"That’s the entire concept of a publicly owned company. AT & T has to give quarterly financial reports because there isn’t a small group of secretive owners - there’s thousands of owners. I own shares. You can own one seven-billionth of AT & T right now for $28.59. You and I may want to know how our company is doing, even though we only own a hilariously tiny percentage of it. Companies can and do stay private, but selling shares of ownership to the public is one of the most common ways to raise a huge amount of money."
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nffpdn | If mass is correlated with potential energy, why do gasoline tanks weigh less than batteries of equivalent energy? Is it because of efficiency? | Physics | explainlikeimfive | {
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"I think when you heard that mass is correlated with potential energy, it was really that mass is correlated with gravitational potential energy, like the formula PE = mgh Vehicles don't use gravitational potential energy to power their engines. Gasoline and batteries both store chemical potential energy, which isn't directly related to mass.",
"The energy stored in something effectively adds to its mass. However, for most things (even nuclear power) the energy-originated mass is insignificant compared to the 'dry mass' of the thing. A charged battery weighs an immeasurably small amount more than a dead one. The same is true for gas and air. So sure, the energy adds the same amount of mass, but the material that is required to store that energy carries a comparatively huge amount of mass with it from the start."
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nffqu5 | Resampling (in audio) | Technology | explainlikeimfive | {
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"Digital audio is stored and reproduced as a list of numbers which tell the speaker how to move. Each one of these numbers is called a \"sample\", because a device is \"sampling\" the voltage from the audio signal wire periodically. In CD-quality recordings, a voltage is sampled and stored 44100 times per second. Some audio devices offer something called \"resampling\". This can mean a few different things depending on context. Often it means changing the sampling rate to something else. If I wanted to reduce my data storage requirements, or get a more gritty, degraded sound, I could resample that 44100-samples-per-second signal down to 22050-per-second, by simply throwing away every second sample. Or, if I wanted a slightly smoother result, Instead of simply discarding every other sample, I could *average* the samples in pairs. Either way, we end up with half as many samples as before. So this is one kind of resampling: Changing the sample rate of a piece of digitized audio. It's analogous to changing the resolution of an image file. Another kind of resampling, is a function in some digital musical instruments, commonly called samplers. In those instruments, you can record and play back little clips of digitally sampled audio, sometimes by triggering them with pads or a keyboard. In these devices, \"resampling\" means that the device can listen to its own output, and record *that* into a digitally-sampled clip. So you might sample some piano chords from one source, and some drum beats from another source, and mix them together in your sampler... and then when you're happy with the mix, you can resample it so that you now have a piece of recorded audio which is the drums *and* the piano together in one sound file. And then you can manipulate that recording just like you did with the other recordings. So in the context of a musical sampling instrument, \"resample\" means \"re-record your own output so it can be further manipulated.\" In the context of a simple recording, \"resample\" means \"change the quality/resolution\""
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nfg18p | How does the pressure regulation mechanism in our ears get "plugged up" when changing altitudes but not when it's windy? | My understanding about the "ears plugged up" phenomenon is that it is related to a failure to equilibrate pressure between the inner and outer ear, due to a rapid pressure change. If so, how do our ears avoid getting plugged up when it's windy (especially "gusty") out? That's also a rapid change of air pressure, as the wind changes direction and/or speed. | Biology | explainlikeimfive | {
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"I don't think wind creates any significant air pressure. Feeling force from the wind is not the same as air pressure. Imagine getting sprayed by a sprinkler vs getting dunked under water. Doing the math, normal air pressure is 14.6 PSI, air pressure say during a flight in the cabin is about 10 PSI. So a difference of 4 PSI. 50 MPH win exerts about 0.07 PSI. That might make high altitude air pressure sound insane, but our bodies can handle this kind of pressure change when it's exerted uniformly around our bodies",
"Because the pressure effects from wind are transient, short-duration. The pressure goes up/down from what you're used to, then quickly returns. Your ear doesn't feel plugged up because it went right back to \"normal\" pressure. If you went up in a plane, didn't pop your ears, then came back down to ground level, your ears would be fine. Most of the time, flights take a lot longer than would be comfortable to have the \"plugged-up\" feeling, so we try to fix it. Then, after we land, we have to fix it again."
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nfg4al | A whole orange will float on water but a peeled orange will sink. Why? | Physics | explainlikeimfive | {
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"The air pockets and oil content in the orange peel keep the entire orange afloat. When you remove the peel, you remove the buoyant part of the entire orange . The peeled orange will sink as a result."
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nfgkl9 | why does breaking the sound barrier create an incredibly loud noise and also why does it create a cone around the jet. also does it do that again if the jet hits mach2 or 3 and so on? | Physics | explainlikeimfive | {
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"As you approach the speed of sound, the pressure waves (sound) coming off the thing can't get out of the way of the incoming object. They pile up. Rather than the spread out \"roar\" we're used to of airplanes or cars, all that sound energy is piled up into a very thin region, called a shockwave. We hear that as a really loud \\*bang\\*. It's a cone around the jet because that's the shape of a bunch of circles lined up and moving. This image should help a lot: [ URL_1 ]( URL_0 ) The angle of the cone corresponds to the Mach number. There's nothing magical about integer Mach numbers, you can go Mach 2.1 or whatever. The cone just gets tighter. As you go faster the shockwave also gets stronger, so louder, but the general sound profile is the same."
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nfhn2x | How would we know if we’re seeing a color for the first time? How are new colors created? | Chemistry | explainlikeimfive | {
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"We actually have [colour databases]( URL_0 ), which colour scientists check to see if a colour they made already exists. If it doesn’t, boom, new colour. To most people, these don’t look like new colours, because they are all variations of colours we are all familiar with like red and blue. > How are colours made? New colours are made by mixing synthetic and naturally-occurring pigments together. There’s obviously more science to it, because colour is created when light bounces off atoms, but overall it’s just mixing stuff together. Hope this helped!",
"Part of this answer ties into the definition of \"Colors\", there is a very human component of this answer that is something like \"when did we start identifying orange as orange and not 'leaf-red' or 'dark yellow'. Very specifically Blue was the most recent color to be defined, as recently as ancient Greece blue *wasn't* a color. The sky was 'colorless' or 'clear', and water was \"wine-dark\". It wasn't until approximately the time of Christ that blue became identified as blue.",
"This isn't really a new 'colour', it's a new pigment. The range of colors that a person can perceive is effectively fixed, we can't discover any more. But materials which are coloured and useful as pigments can be developed."
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nfhvme | How Does Radio & Royalties Work? | I have no idea how radio works. Do they pay a royalty every time they play a song? How much is a typical royalty for a popular pop song? Who decided what the royalty will be? How do they (the artist or their managers) keep track of how much each radio station in the world owes them? | Technology | explainlikeimfive | {
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"You're confusing royalties and licensing fees. There are several companies that do broadcast licensing for music. A radio station pays one or more of those companies for the rights to broadcast some or all of the music by the artists that company represents. The licensing company then pays some agreed upon amount to the record company (or the artist directly, if they're independent). The record company then pays royalties to all of the musicians/producers/etc. that are entitled to them via their contracts."
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nfi3kw | - was there oil in the ground back in the days of the early dinosaurs? | Earth Science | explainlikeimfive | {
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"Most of the fossil fuel we extract today is indeed older then the dinosaurs but not that much older. We do of course have fossil fuel from various different ages. However most comes from the carboniferous era. This was when plants developed plastics like lignin which enabled them to develop strong stems like for example in trees. However bacteria and insects had not developed the ability to digest these plastics and so the forest floors became covered in layers upon layers of dead trees and plants that would never fully rot away. And this is what eventually became oil and gas. When bacteria finally were able to digest lignin this caused a collapse of the forests, desertification, development of various animals and plants better equipped to this new climate like for example reptiles and then after 50 million years of this we got the biggest recorded mass extinction event that lasted for about 30 million years and triggered the development of dinosaurs. For comparison the dinosaurs were around for about 200 million years and became extinct only 66 million years ago.",
"Most likely. Since the oil is from algae and zooplankton decomposing in oxygen free environments. And those have been around since long before the dinosaurs"
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nfkdfp | What are quasicrystals? And what's different about the Red Trinitite formed at a nuclear test site? | Chemistry | explainlikeimfive | {
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"Quasicrystals have a clear internal structure but do not conform to the symmetry and other structure rules of crystals. They have unusual symmetries and repetition. A quasicrystal is an \"almost-crystal\". Crystals are highly structured and have what's called \"periodicity\". They have a set of molecules called a 'cell' that is in a specific configuration, such as a cube with specific molecules at the same corners, and that cell is repeated over and over with consistent spacing, connections, and molecules. This high repeatability is part of the definition of a crystal. This periodicity leads to translational symmetry, which is to say if you picked up one part of it and moved it in a straight line, you would be able to find another part of the structure that it lined up with perfectly. Finally, crystals can have 2, 3, 4, and 6-fold rotational symmetries, but not 5-fold symmetries. *n*\\-fold rotational symmetries mean the number of times *n* during a full rotation where the structure looks identical. For example, an equilateral triangle (all sides and angles the same) has 3-fold symmetry and a square has 4-fold symmetry. I think the theorem behind why 5-fold symmetry is not a crystal but instead a quasi-crystal is beyond the scope of the original question. Essentially, you can't make a proper lattice that has 5-fold rotational symmetry. There's a very technical explanation here: [ URL_2 ]( URL_0 ) We have yet to find a naturally occurring quasicrystal formed on earth. Previously, we thought the first synthetically made quasicrystal was formed in 1981, by scientist deliberately trying to make one. Most quasicrystals are from man-made metallic alloys, often involving aluminum ([source]( URL_4 )) The only quasicrystal found in nature so far is [icosahedrite]( URL_3 ), which came from a meteorite (and thus was not formed on Earth). We didn't know it at the time but Red Trinitite, first created in 1945 in a nuclear test site, is a quasicrystal. We only *just* discovered that it's a quasicrystal, but since it was formed in 1945, it's the first known occurrence of a man-made quasicrystal. They went looking for it after the theory behind icosahedrite was formed: two meteorites crashing into each other at very high speeds during the early stages of the solar system ([ URL_1 ]( URL_1 )). Scientists have also formed synthetic quasicrystals using high speed collisions, so they theorized that nuclear detonations might *also* have formed quasicrystals --- and they were right. **tl;dr:** quasicrystals are rare and likely do not occur naturally on earth. Red Trinitite is special because it's the oldest known instance of humans making a quasicrystal, and it proved a theory that quasicrystals could be made from nuclear explosions. We made them before we knew they could even exist, and that's kinda cool."
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nfksvf | When you remove large part of the skin after weightlose, what happens to the feeling between, do you feel a jump? | Was kinda hard to explain just as a title, but the question is this: If you have a large patch of skin removed, for example after large weight loss, what happens to your perception of your skin/surface? So if you brush from one side of the scar to the other side, does the brain know/adjust so there is no jump between the feeling? Because the might have been 10 cm between that area before. Like if you close your eyes and touch on two areas of your arm, you kinda know how far it is between it, but what happen in this case if you remove skin? | Biology | explainlikeimfive | {
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"There is no jump, but some areas may go numb where the nerve endings were severed. Some recover with time, some never do."
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nfl3xc | How does a country know if a plane flying over it's airspace is civilian or military & more importantly how do they know if a military plane using the airspace is friendly or not? | Technology | explainlikeimfive | {
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"Civil aircraft file flight plans with air traffic control and have transponders to identify themselves. Military aircraft have an extra transponder called an IFF (Identification Friend or Foe) that civil aircraft don’t. So if it’s transmitting IFF it’s definitely military. The reverse isn’t true…a military aircraft can turn IFF off and “look like” a civil aircraft if they stick to the same flight path (altitude & speed). If it’s transmitting nothing it’s also obviously military (or a no-radio civilian, which is rare). The only way to know for sure is visual inspection…if a country is suspicious, they will dispatch fighters to go look and see what it really is. In an actual war, this is a fairly common thing. In peacetime, most countries play nice because if you try to sneak a military aircraft in as a civil aircraft, that country is quite likely to bar *all* your aircraft from their airspace. And spark a diplomatic incident. So, outside active conflict, it’s best for everyone to have all aircraft report what they really are.",
"Planes that enter a nation’s airspace must respond to radio contact from that nation’s air traffic control. If they’re unable or unwilling to provide identification and flight plans, they may be intercepted by the local air force. Developed nations have extensive radar networks that constantly track all air traffic. Any incoming aircraft that’s refusing to identify itself would be picked up on radar quickly and ordered to land. Refuse all radio commands and angry gestures from intercepting fighter pilots and you may be shot down."
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nflbhq | Why are nuts so filling and calorie dense? | Biology | explainlikeimfive | {
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"They’re the plant equivalent of egg yolks. They’re designed to feed the growing seed so they stuff as much nutrients into as small a package as possible.",
"The same reason egg yolks are energy dense. They contain the food necessary for the plant to start growing.",
"Nuts have fairly high amount of fat. Fat is more calorie dense than protein or carbs, and many people find it to be filling."
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nflhcz | Why do we stick our thumb up in the finger gun sign | Other | explainlikeimfive | {
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"It's supposed to be the hammer of a revolver. That's why you'll sometimes see someone bend the thumb too",
"Some guns have a hammer that sticks up, about 1 cm. Your hand isn't the right scale, but finger guns isn't a precision activity."
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nfo9e6 | How did ancient Polynesians first find all the remote Pacific islands? Did they just sail in random directions hoping to find land? | EDIT: Please stop giving this post awards. There's no reason to give money to reddit because you like my post. If you really feel compelled to spend money, donate the price of the award to charity or something. | Other | explainlikeimfive | {
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"So, as others have mentioned, waves bounce off of islands, so that's one method. Another is that clouds tend to accumulate over islands (different air patterns over land than water), and *birds* were a big help. They figured that if they spotted a bird at sea, it was either headed *from* or *toward* land, or food, since it had to have nests somewhere. They could easily use other methods to determine if the birds were leaving land, though time of day was a big factor. (If it was morning, they were leaving the nest to hunt. If it was evening, they were returning to the nest to sleep.) Combine this with eventual familiarity with local currents, and likely *generations* of experience passed down through oral tradition and recordkeeping (they didn't do it overnight, after all.), and there you have it. I am by no means an expert on this topic, so I likely missed some things, but I did look into it at some point in the past year or two. Edit: As some people pointed out, *yes*, at night, they could navigate using the stars and night sky. This could be as simple as following the correct stars for a direction, to as advanced as measuring how high a constellation has risen over the horizon relative to global position and time of night to track progress, using nothing more than your hand, the star and the horizon as a measuring stick and points of reference, and the positioning of the moon to track time of night.",
"There's a lot of good information here, but I haven't seen anyone directly answer the original question. The navigation methods people are discussing are all correct, but to answer, yes, they did pick a direction and just sail off. When they were heading to a familiar location, they would sail north or south to the precise latitude, then head east or west. There's no way to measure longitude without a precise chronometer, which wasn't developed until pretty late in history by the Europeans. However, they could estimate with a sufficient accuracy. Their latitude measurements were incredibly precise. Over the course of hundreds of miles, they could come within a few miles of the exact spot they wanted by the use of a type of [astrolabe]( URL_3 ) literally made from a coconut shell. If, instead, they were exploring in search of new lands, they would choose a compass heading and go off for 10 days. If they didn't find any evidence of land, using the methods others have already described as well as some additional ones, like types of fish encountered, they would reverse course. This brings up a very interesting historical mystery. Hawai'i is much farther away from the rest of Polynesia than the other island groups. It was settled from the Marquesas Islands, which are 20 days sail away. The voyagers would carry 24 days worth of supplies on exploration missions: 10 out, 10 back, 4 days reserve for storms and such. How did they discover an island chain twice as far away as they normally explored? The conventional explanation for decades was that they simply got lost, a ridiculous theory as soon as you learn anything about Polynesian wayfinding. [Thor Heyerdal]( URL_0 ) proposed that ancient people could have crossed the Pacific and even proved it with in a ship made from traditional materials. He got the direction wrong, going east to west, but he at least laid the groundwork for believability. Polynesians have insisted for all the time they have been in contact with others that their ancestors settled the Pacific deliberately. In 1973 the [Polynesian Voyaging Society]( URL_2 ) was founded to prove that the oral history was accurate. The [Hōkūleʻa]( URL_1 ) was built as a replica of traditional Polynesian ships for that purpose. In 1976, she completed a journey to Tahiti using only traditional Polynesian Voyaging techniques. She has completed several other journeys since then. A sister ship, the Hikianalia was built along the same design, but using only traditional materials. This ship is equally capable of voyaging, but isn't used as much because of the vastly increased maintenance needed. Both ships completed a three-year circumnavigation of the entire globe on a goodwill mission, visiting indigenous communities around the world. There's no evidence that the Polynesians ever left the Pacific, but we know know they could have if they wanted to. So, back to the mystery of Hawai'i's discovery. The oral history says that a legendary navigator named Hawai'i Loa was given a vision from God to sail on a certain heading in order to find paradise. He set out on a trip that would be one-way if he didn't find his destination. There are many ways to rationalize the discovery with reasonable explanations, but if you ask nearly any Hawaiian, they will insist the story is true. The one thing we know know for sure is that the Polynesians were fully capable of settling the Pacific using the technology they had at the time.",
"I was listening to some podcasts on the subject. In addition to what other people said, they sent out active explorers looking for new islands and even had a standard way of organizing a new colonial fleet. It was very purposeful. The explorers did in some cases set off in random directions, but they had ways of looking for land as other people had already explaining, and knew now to reliably return.",
"This will probably get buried (and maybe was already mentioned, but... It's not just the clouds, but the color on the underside of clouds. Lots of green reflects differently than blue or gray. Also, I have see the current maps made by the Polynesians, which matches the description of what the Marshallese use. The only difference on the one I saw included sewed on little cowrie shells indicating the position of known islands.",
"The ancestors of Polynesians came from what is now Taiwan, apparently. Indigenous Taiwanese, that is, not the Han latecomers who followed Chiang Kai Shek off mainland China. They went south and some populated SE Asia (becoming Indonesians, Malaysians and Filipinos), and others went on all over the Pacific as Polynesians. Southeast Asians learned ironworking, while Polynesians never found useable metal deposits on the islands and were stone-tech until European contact. Curiously the Polynesians also had no tradition of pottery. They had gourds but no clay pots.",
"what I was told on Tonga, was that in addition to things mentioned already like birds and waves bouncing off land. Such as, feeling turbulence, or a \"wake\" thrown off by islands as the ocean currents cut around them. you sail into that, feel it, and follow it to land. Then another thing was, apparently, there are relatively consistent swells that come from the same direction, we don't notice them because of all the surface waves, but the skilled navigators could pick them up and use them as a reference, I think also they might get disturbed or blocked by a land mass, not so sure about that last bit, or any of it, I went to Tonga once and it was badass",
"Surprised none of the top comments mentioned this, but they didnt just pay attention to birds migrating to orient themselves, they also actually caged and brought some sea birds with them. They were periodically released so they could get their bearing. Source: saw it on the new cosmos with ol' Niel Degrasse Tyson",
"No they, they used a wide variety of wayfinding techniques that others have mentioned - wave patterns, currents, maps, birds. Also you can tell if there are islands over the horizon based on cloud formations that gather over the land. They were incredibly skilled navigators - the sea was basically the core of their lifestyle.",
"Also, aside from these other reasons. Have you ever looked at the Hawaiian archipelago. Its massive, spanning like 1/3 of the whole Pacific Ocean. The waters change significantly once your in the archipelago too so even if you dont hit one of the islands you'll know they're nearby. Once the ancient Hawaiians hit the archipelago they just sailed south to bigger and bigger islands until they hit the main 7",
"As many have pointed out, various techniques involving the use of the sun/stars, wave patterns, wind patterns, etc. Polynesians were highly skilled navigators and they passed down these skills for generations. They did not find the islands accidentally as many would have you believe. If you are interested in further reading, I suggest researching people such as Nainoa Thompson, Mau Piailug, and Herb Kāne. If you are interested in the cultural significance of your question, I recommend the book Hawaiki Rising by Sam Low. Navigation was/is a critical aspect of Polynesian culture, and the identities of the Polynesian people is very closely tied with the ocean. With the successful voyages of the Hōkūle'a beginning in the mid-to-late-70s there was a Polynesian cultural revival (specifically Hawaiian) that provided a renewed perspective on how these people navigated and how remarkably brilliant they were.",
"I asked this same question in an anthropology class @ University of Hawaii. prof: well, how have humans usually found new places? me: by just... exploring? you can't blindly wander the ocean tho, it's too dangerous prof: and exploring the land isn't? i think the issue is you look at the ocean as an obstacle, whereas polynesians do not. in their eyes, the ocean is a highway",
"They didn't have magnetic compass so they used stars or bright planets such as Venus and Jupiter to navigate during the night. During day time they use the sun to navigate. When near an island there would be birds and cloud formation. The Māori name for New Zealand is Aotearoa with one literal translation as 'the land of the long white cloud' given by them when they discovered the North Island. The Māori voyagers also used whales to find land in this case it was the Humpback whale. They believed that by following whales they would be led to land as whales give birth in calmer water near atolls or islands. Whales travel slowly at around 3 to 5 knots thus making them easy to follow. This is the [source]( URL_1 ) about finding land. [Here]( URL_0 ) are the different stories about the Māori origins and arrival.",
"For Hawaii, which is one of the more remote groups of islands, two possibilities come to mind: Pumice. Hawaii is volcanic, and while most eruptions are the familiar rivers of lava [there are exceptions]( URL_0 ). The maps I see online show a current flowing westwards from Hawaii, so if the Polynesians encountered relatively fresh pumice coming from the east they would suspect there might be land there. Those same currents would carry rafts of terrestrial vegetation torn loose by heavy rains, which would be an even stronger indication of land to the east.",
"I believe in New Zealand's case, it was likely to be the birds. Migrating birds flew over a land mass yearly (forget which), and someone noticed them flying in our direction and figured out there had to be a more land down there.",
"Well, you ask this question in an interesting way. *\"First find.\"* First finding the islands was probably no different for Polynesians than it was for anyone else who has ever sailed the deep oceans. You mostly find islands -- as in, discover them for the first time -- by accident. Maybe you are on a voyage between two other points and get blown off course for a while. Or maybe you have set out with X amount of food and fresh water, and you are going to see how far you can go before you have to turn around, hoping to get lucky this time. In any case, it comes down to chance. The reason for this is that the ocean is overwhelmingly empty. On any given voyage, you are mostly not going to find anything out there, not even at some great distance. But, like anything with a low but nonzero chance of success, if you keep going out there over and over and don't die, you might eventually catch some trace of an atoll or a distant cloud just over the horizon, or birds or fish that you recognize as living close to land, and you combine that discovery with some intuition and maybe discover a new island that nobody knew was there. That is basically the same for everyone around the world at every time in history. (Up until aircraft and satellite maps.) But all that is totally separate from how you navigate. By definition, you don't navigate ***to*** an undiscovered island. So a lot of the answers here seem to slightly miss the point. But only slightly: for your discovery to matter at all, you do still have to navigate home! I think that is the missing piece... you as a hypothetical Polynesian master sailor had to track down this undiscovered island, all while keeping in your mind a mental map of how to get back home afterward, and then achieve that return trip using many of the methods described here."
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nfoo2y | How did we measure the distance between the sun and the earth? | Physics | explainlikeimfive | {
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"You have to start before that. The first distance to be measured with any accuracy was that of the Moon. In the middle of the 2nd century BCE, Greek astronomer Hipparchus pioneered the use of a method known as parallax. The idea of parallax is simple: when objects are observed from two different angles, closer objects appear to shift more than do farther ones. You can demonstrate this easily for yourself by holding a finger at arm's length and closing one eye and then the other. Notice how your finger moves more than things in the background? That's parallax! By observing the Moon from two cities a known distance apart, Hipparchus used a little geometry to compute its distance to within 7% of today's modern value. With the distance to the Moon known, the stage was set for another Greek astronomer, Aristarchus, to take the first stab at determining the Earth's distance from the Sun. Aristarchus realized that when the Moon was exactly half illuminated, it formed a right triangle with the Earth and the Sun. Now knowing the distance between the Earth and the Moon, all he needed was the angle between the Moon and Sun at this moment to compute the distance of the Sun itself. Aristarchus estimated this angle to be 87 degrees, not terribly far from the true value of 89.83 degrees. But when the distances involved are enormous, small errors can be quickly magnified. His result was off by a factor of more than a thousand. Over the next two thousand years, better observations applied to Aristarchus' method would bring us within 3 or 4 times the true value. There was still only one method of directly measuring distance and that was parallax. But, finding the parallax of the Sun was far more challenging than that of the Moon. After all, the Sun is essentially featureless and its incredible brightness obliterates any view we might have of the stars that lurk behind. Enter planetary relational distance and the key is the transit of Venus. Johannes Kepler and Isaac Newton had shown that the distances between the planets were all related; find one and you would know them all. During a transit, the planet crosses in front of the Sun as seen from Earth. From different locations, Venus will appear to cross larger or smaller parts of the Sun. Kind of like a planetary eclipse. By timing how long these crossings take, James Gregory and Edmond Halley (the comet guy) realized that the distance to Venus (and hence the Sun) could be determined. This presented a small problem though. Venus is only in transit once a generation (though often come in pairs). By the time Halley realized that this method would work, he knew that he was too old to have a chance to complete it himself. So, in hope that a future generation would undertake the task, he wrote out specific instructions on how the observations must be carried out. In order for the end result to have the desired accuracy, the timing of the transit needed to be measured down to the second. In order to have a large separation in distance, the observing sites would need to be located at the far reaches of the Earth. And, in order to ensure that cloudy weather didn't ruin the chance of success, observers would be needed at locations all over the globe. Despite these challenges, astronomers in France and England resolved that they would collect the necessary data during the 1761 transit. Although not all observers were successful (clouds blocked some, warships others), when combined with data collected during another transit eight years later, the undertaking had been a success. French astronomer Jerome Lalande collected all the data and computed the first fairly accurate distance to the Sun: 153 million kilometers, good to within three percent of the true value! By the way, the number we're talking about here is called the Earth's semi-major axis, meaning that it's the average distance between the Earth and the Sun. Because the Earth's orbit isn't perfectly round, we actually get about 3% closer and farther throughout the course of a year. Also, like many numbers in modern science, the formal definition of the astronomical unit has been altered a bit. As of 2012, 1 AU = 149,597,870,700 meters exactly, regardless of whether we find the Earth's semi-major axis is slightly different in the future. Tl;dr: Bunch of guys, over a period of two thousand years, armed with a bit of creative ingenuity and a celestial phenomenon, used high school level trigonometry to figure it out.",
"The ancient Greeks were the first to measure the distance, and the way they did it was very clever. First, Eratosthenes measured the size of the Earth, which you may have learned about in middle/high school. He knew that on a certain day, the sun would be directly overhead in Egypt... and in Greece he could measure the length of a shadow when the sun was at its highest point. He then used the length of the shadow along with the distance between Egypt and Greece to calculate the circumference of the Earth. Next, the Greek's figured out the size of the moon. They did this during a lunar eclipse, when the Earth cast its shadow on the moon. By measuring the size of Earth's shadow, they could determine the size of the moon. And if you know how big the moon is, and how big it appears, you can calculate how far away it is. The final step is to calculate the distance to the sun. On a perfect half-moon, the Earth, Moon, and Sun form a right triangle (with the 90 degree angle at the half-moon). Now, since you know the distance from the Earth to the moon, you can measure the angle between the sun and the moon, and use a little SOHCAHTOA to calculate the distance from the Earth to the sun. Sadly, this method is not super accurate, but it does give some sort of answer."
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nfovc5 | Why is it so common to have low back pain? | Pretty much the title. | Biology | explainlikeimfive | {
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"It's only relatively recently in our evolutionary history that we started walking upright. Our lumbar essentially hold half the weight of our body. It isn't an optimized set up. Nature basically took what was originally meant to function as a close line and tried to make a totem pole out of it. Evolution hasn't had time to work out all the bugs yet."
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nfq8p4 | How does a VHS/DVD that was once 480 or 720p become 1080p, and why aren't all old releases available in higher resolution or better quality? | Technology | explainlikeimfive | {
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"The classic case to look at is the remastered Star Trek The Next Generation. The principal photography (real life actors on sets) is fine for HD because it was recorded with a 35mm camera which looks great in 1080p and would even look great in 4k. The problem with TNG was all the special effects (ships, planets, consoles, phasers, etc.) were recorded at a resolution which was fine for TV at the time but looks like crap at higher resolutions. Nobody at the time realized how much resolution would improve in the next 20 years. So virtually every single special effects shot had to be redone which is time consuming and very expensive.",
"If something was filmed on a real camera, like what was used for movie production, it actually has an extremely high resolution, because film doesn't need processing power or special chips to record ultra high def images. So they used to take that super high resolution and scale it down to 480p or 720p to be stored on VHS or DVD. To re-release something in high def, they take the original camera film and work from that. If the owner doesn't want it re-released, it doesn't happen. If the special effects look like shit in higher resolutions, they might choose not to release it. If the original film is lost or damaged (fuck you George Lucas) then you can't do anything with it.",
"Actual physical film often produced very high-resolution images, higher resolution than the digital scanners of the time could reproduce. Now our digital scanners are better, so they can re-scan old film at a higher resolution than they did before. As for why they don't always go back and re-scan: sometimes there's just not the demand for it, and re-scanning and re-releasing the new version is an expensive process. Also, if there's digital effects, the film might not have them, or would be a low-resolution copy of the shot film with the effects added; either way you'd have to redo a lot of those effects from scratch to get them in the update.",
"If it's a straight VHS or DVD rip then it's a lot of attention to detail from fans of that movie/show to fill in the blanks detail wise and improve image quality. If it's something that was once released on VHS or DVD but was recorded in a studio environment then remasters may re-scan the source film, and since film is high resolution(in it's own way but that's a topic for a different comment) it can be 1080p or even 4K, but anything done in editing has to be recreated digitally."
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nfqhfm | What exactly happens to the skin when the sun hits it and tans it? | What exactly happens to the tissue/cells? Do they get damaged or is more melanin created to get the tan effect? What happens exactly? | Biology | explainlikeimfive | {
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"UVA rays penetrate your skin and activate cells in your lower epidermis called melanocytes. Those cells then produce the melanin pigment that leads to your skin tanning and turning darker/brown. This melanin naturally absorbs UV rays to protect your body from the harm that is caused by them. Essentially your body builds up a UV tolerance the more exposure you get."
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nfr4bu | Why didn't Latin survive in the British Isles after the Roman Empire fell, whereas in mainland Europe, Latin replaced the local languages and became the modern Romance languages? | Other | explainlikeimfive | {
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"When rome fell the lands were settled by Germanic tribes. However these varied heavily. The goths who settled most of it were already a form of Christianity. The franks who settled France were friendly-ish border tribes of rome for centuries. These assimilated the native regional Roman culture and religion of the lands into their own kingdoms. The tribes that settled britain originated from an area never touched by Rome and couldn’t care less about the culture and religion. Plus the Romano-Briton control and population was more sparse than on the continent so it was more easy to dominate the language and culture into the Anglo Saxon form.",
"Because of the invasion of the British isles by the Germanic tribes of the Angles, Saxons and Jutes. They took their language to what is now England (England itself means Land of the Angles) and their language evolved into what is now English. The Angles and the Saxons is why English people are known as Anglo-Saxons (apparently the Jutes could go jump).",
"I'm pretty sure the areas where the Romance languages were established were more foundational to Rome's Empire and their own dialects already formed. Latin might not have been quite as old further North. It didn't stick with Austria either, after all."
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nfrata | What makes the Swiss banking system a safe haven for criminals and multi-millionaires? | Economics | explainlikeimfive | {
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"The Swiss take privacy extremely seriously. You have to be involved in a very serious crime before the Swiss banks even acknowledge your account’s existence to any government. Add in the extra layer that the US government would have to go thru the Swiss government and its even more secure. Swiss accounts have fallen out of favor in the past few decades as more countries have even more strict privacy laws and less taxes. There are a bunch of small island countries that are better suited for hiding money.",
"It's an account number and password with no name attached to the account. Without having a name attached to the account court's have no definitive proof that the account is yours and cannot seize the assets."
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nfsdjf | How do car scratch remover compounds work? | Does it thin out the body paint? | Chemistry | explainlikeimfive | {
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"From a post on Quora: [ URL_0 ]( URL_0 ) They remove a small layer of the clear coat and debris that might have been left behind, which makes a smooth surface. If you read descriptions for the scratch removers, they talk about \"microabrasive technology\" --- their point is that it will end up smooth because it removes things in *very* small pieces, compared to an extreme of, say, taking a steel wool pad to it. Kind of like buffing a nail, actually.",
"Scratch removing compounds are very fine abrasives. When you apply them and rub continuously - they remove the surface (paint) in very thin layers. So if the paint thickness is say 100 units and the scratch is say 10 units deep - the compound will keep removing say 1 unit of paint after every application. So after about 10 applications - the paint is removed uniformly upto the scratch depth and then on the 11th application - the underneath fresh paint is visible at the scratch location (and also sorrounding areas) and voila - scratch be gone. These compounds work only for very superficial scratches (anything deeper than the paint thickness will not be removed using these compounds)."
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nfsuzq | How Can the Diameter of the Universe Exceed its Age? | Basically, how can the universe be 93 billion light-years across if it is only 13.8 billion years old and nothing can travel faster than light? | Physics | explainlikeimfive | {
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"The *expansion* of Spacetime can be faster than the speed of light. What actually *is* Spacetime? Nobody knows. Somehow time and space are the 'same', sort of. Does that make sense? No, it does not. Here's something else that doesn't make sense, but is true- The speed of light is different than any other speed, and light can basically do magic. Light can basically just ignore time and exists in it's \"own time\". The speed of light is constant, no matter the speed of the observer. Meaning, no matter how fast you are moving, the speed of light will always move away from you at the speed of light. Here's what I mean: Suppose you're standing still and a car passes you at 60 mph. That car will be moving away from you at....60 mph, right? Now say you're in a car driving 30 mph, and another car passes you at 60 mph...that other car is only moving away from you at a rate of 30 mph, because you're making up half the difference. Light doesn't do that. If you're standing still and turn on a flashlight, the beam will move away from you at...the speed of light, right? But....if you're in spaceship moving half the speed of light, and turn on a flashlight forward at the cockpit, that beam will still be moving away from you at the speed of light. Even though you're making up half the difference, it doesn't matter, from your perspective, the light will still be moving away from you at the full speed of light. And the light hasn't gotten any faster, it just...does that anyway. And someone watching you will see that the speed of light is only going the same speed of light. This happens because time actually *changes*, it's called [time dilation]( URL_0 ). Speed actually changes how time works, and for someone going half the speed of light, time is actually moving more slowly for them, giving light a chance to maintain it's constant speed. How is that possible? It's not, but it still is anyway. How? we don't know.",
"Nothing can travel through space faster than light. But space can do whatever it wants. As far as we can tell, the universe is expanding faster than the speed of light. We can see light from objects that was emitted 13.8 billion years ago. Those objects, if they still exist, are now much further away (45 billion light years) due to the expansion of space.",
"The fabric of space-time has no mass and therefore is not constrained by the speed of light. Also, it’s worth noting that we don’t really know how big the universe actually is. Most estimates are based on theoretical models, and the size of the universe (if it has one as we would understand it) is a contested topic.",
"My understanding of it is as follows: When people say \"space is expanding\" the common understanding is that we're all hurtling away from the 'ground zero' (i.e. the point in space where the universe started) However, as some others have mentioned, every point in space seems to be moving away from every other point. Wherever you stand *appears* to be 'ground zero'. What this means is there's no real \"centre\" or \"ground zero\" that is a *place in space* where the initial explosion started. Instead, \"spacetime\" is more like the skin of a balloon. It's *inflating* and *stretching.* At the \"beginning\", space was a deflated balloon, with all of the matter being points on its surface and being really close - we're pretty sure infinitely close, but that's a story for another time. Then the balloon begins inflating. The points on the surface of the balloon (the matter) aren't moving *through space* away from one another - rather, the space *between* the points is stretching. Now matter, energy, subatomic particles, you name it - the speed limit law is, to the best of our knowledge, universal. None of these things can **move through space** faster than the speed of light. But there's no \"movement\" happening as the universe expands. Rather, the balloon is expanding so that there is basically just *more* space between any two points. The 'universal speed limit' law is imposed upon things moving in space - e.g. a dot on the surface of our balloon actually, physically moving to a different point along the surface of the balloon. In our analogy, as the balloon inflates (the universe expands), the dot doesn't actually **change it's position.** Since there's no movement, nothing is breaking the universal speed limit law. The universe is simply growing and stretching. & #x200B; At least, that's the reasoning as it stands (and as I understand it).",
"The *observable* universe is around 93 billion light years, we have no idea how big the universe is. Because of many astronomical observations we've made, we have good reason to believe space is expanding. Because the universe is expanding, something at the edge of the observable universe (currently around ~46.5 billion light years from earth), was less than 13.8 billion light years from earth at the time it gave off the light that's currently hitting Earth, but now it's father away. We arrived at the 13.8 billion year number using the size of the observable universe, the rate of inflation, and other physical observations to make a best estimate according to currently physical models. Also, not sure if this applies to you, but a lot of people think all of the matter in the universe was compressed to a single point at the moment of the big bang. That's not true. The models suggest infinite density, not zero volume. Even then, physicists universally agree that's a failure of the model."
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nft8jf | if it’s true that human can survive for weeks or months without food then why is it so difficult for most people to go more than a day without eating? | Biology | explainlikeimfive | {
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"You \\*can\\* survive for weeks without food, but your body really does not want to do that. It's the emergency backup mode. Our cells use glucose as fuel, which we get from breaking down the food we eat. Our bodies can only store glucose for a few hours, which is why we generally get hungry roughly that often. If you continue to not eat, your cells run out their primary source of fuel and your body goes into emergency backup mode which is breaking down fats and proteins in your body for energy, but your body desparately wants to go back to its normal fuel source (you eating food regularly) as soon as possible. Think of it this way: Yea, you \\*can\\* drive your car around on a donut tire if you get a flat, but it's only meant as a backup to get you to a repair shop to get a new tire asap. It's not meant to be driven on like a regular tire, and it's dangerous if you do.",
"Going weeks/months without food whilst you can survive if you have sufficient fat on your body - its not without its drawbacks on your health and is there for not something the body wants you to do. So when you don't eat your body will send signals to tell you \"hey get some food now! you might need it !\", since you never know when the next lion might want to hunt you down for over 1km to eat you - you need to have food constantly ready as humans are long endurance animals. These signals can be quite strong - main one being stomach hunger pangs (not to be confused with a typical hungry tummy). People who do keto diets also some times experience tough symptoms at the start as well that they have to persevere through as the body is trying to motivate you to hunt for food. If you combine this with some people who associate mental wellbeing with eating food then this is even more difficult of a signal to ignore which is why a lot of people find food comforting and thus find it harder to ignore those signals of \"eat now!\". And also explains why depression and weight gain is commonly seen together. These horrible feelings of starvation can be avoided if you eat regularly - which nearly all humans are there for motivated to do so by making sure they have a secure supply of food at all times. It's also even debatable whether humans are supposed to be eating little and often vs 3 meals a day, i don't think science really knows for sure which is ultimately most beneficial to health yet."
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nftboi | How do the little name keychains work. there isn’t a battery i need to change and it always lights up. Flashes my name at me and i’ve always wondered how it works | Technology | explainlikeimfive | {
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"There's a battery. You just can't access it or see it. The lights take little enough energy to last a long time without changing the battery. Eventually it will die.",
"Looking for similar products online, I believe they are solar powered. Not sure where the panel is. URL_0"
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nfts8i | Why does the moon turn red? And why does it turn yellow?And why does it sometimes become supersized? | Physics | explainlikeimfive | {
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"It only becomes red during a lunar eclipse when the sunlight hitting the moon has passed through the atmosphere of the Earth on the way to the moon, essentially casting a \"sunset\" color all over the moon. And It can seem kind of yellowish when it's low on the horizon as the moonlight passes through the atmosphere. And it's never really \"supersized\". It can be very slightly larger during different parts of its orbit, but not really by any noticeable amount. It just looks bigger when it's a full moon for obvious reasons, and it can also seem larger when it's on the horizon compared to when it's sitting all alone straight up above you because you can compare the size to mountains and other objects on the horizon."
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nfu0mb | why are TVs not the same dimensions as movies? | Technology | explainlikeimfive | {
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"Filmmakers can choose the ratio they want their movie to be shot in. This means that you might sometimes have a movie that doesn't perfectly fit your TV screen. For example, Stanley Kubrick's _Full Metal Jacket_ is shot in 1.375 : 1, which Kubrick chose to do since that was a common aspect ratio for TV screens in the 60s and 70s. This would help immerse the viewer in the movie, giving them the feeling that they're watching the Vietnam War unfold before their eyes in a similar way to those who watched it on the news during the 60s and 70s. 1.375 : 1 is known as the \"Academy Ratio\". As you probably know, the shapes of TVs have changed quite a lot since the 70s, hence the particular ratio he chose will likely not fit many TVs nowadays. However, a more common film ratio is 2.4 : 1, known as \"ultra widescreen\". This more resembles what you see on your TV and in theaters with most movies. However, if you're watching an ordinary TV show or broadcast, it will likely be in 16 : 9, the most common ratio. To summarize, film ratio is all about the filmmaker's choice. It provides a massive stake in helping immerse the viewer in their film, based purely on what it feels like to watch that ratio.",
"Do you mean older 4:3 TVs? Because that was the standard for broadcast television for decades. Most if not all new TVs are 16:9 which is widescreen and what most shows and movies are shown in. Some movies, for example Blade Runner, are 2:39 : 1 which is super widescreen."
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nfufmk | How is non-dairy yogurt made? | Correct me if I’m wrong, but I have the basic understanding that yogurt is made by letting bacteria ferment in milk. During this fermentation process, the bacteria turn lactose (sugar found in milk) into lactic acid, and this is what creates yogurt. If lactose is sugar found specifically in milk, then there wouldn’t be any lactose found in soy, almond milk, etc? How can the bacteria make lactic acid with no lactose? | Chemistry | explainlikeimfive | {
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"text": [
"According to [the first Google . for \"[how is non-dairy yogurt made]( URL_0 ),\" it's pretty much the same as fermenting dairy except you may need a thickener to get it to set and could need to add a little extra sugar to jumpstart the fermentation."
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nfuv1z | -How does blood sugar not drop until it gets to zero | For example- I’ve never seen mine lower than a certain number. I don’t understand how it doesn’t just keep dropping for a non diabetic. | Biology | explainlikeimfive | {
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"For a non-diabetic, when your blood sugar gets low, your body (I think liver) releases more into your blood stream. Your body can naturally regulate your blood sugar unless you are diabetic or one of the pre-diabetic conditions.",
"Thank your pancreas. It controls your blood sugar by releasing/or not, insulin. Insulin enables your cells to absorb energy from your blood (this is simplistic). I’ve been diagnosed with Type 1 diabetes (which is way different from Type 2), in February this year and this is my basic understanding (still learning myself) the guys at r/diabetesT1 will be able to explain in depth how it works. I can say that going to zero is the most god awful thing to experience and so is going into DKA (high). Just thank your pancreas, the little dude doesn’t get the credit due to it.",
"Your body keeps blood sugar at a relatively balanced level to ensure cells always have an energy source but also to prevent issues with blood filtration. The body stores sugar in many ways and has paths to keep this number relatively consistent unless you are diabetic.",
"Your body regulates blood sugar levels because that's what your body needs to stay alive. It will break down glycogen (a storage molecule made of lots of glucose) in the liver and muscles into glucose and secrete that into the blood stream to keep the levels within a controlled range."
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nfvn1s | - What is the difference between interferometry and spectrometry? | Physics | explainlikeimfive | {
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"Interferometry uses light overlapping with itself, but with different offsets to measure distances. Light is a wave and so if peaks line up with peaks you see brighter light. If peaks match up with troughs then everything cancel out and you see no light. If you can create a physical setup, where one ray of light has to travel slightly longer or slower compared to the other, so that it is offset, then you will be able to see a change in brightness at the end. If, as you change your parameters, the light gets bright and then dark again x times, then you know that the offset between the waves now is x wavelengths long. Since you can pick light with very small wavelengths, this allows for incredibly accurate measurements of distance, wavelength, etc. Edit: anything wave-like can be used for interferometry. For example, since neutrons can act like a wave, you can have neutrons interfere with themselves as they travel through a crystal, which gives you information about the structure of the crystal. Spectrometry is about measuring spectra. Spectra, in the classical sense are about seeing how much light you get at different wavelengths/colors. This works by separating light of different wavelengths/colors out (think rainbow) and then looking at each color and seeing how bright it is. Plot color vs brightness and you get a spectrum! In truth spectrometry is much broader than this though. Brightness is really just telling you something about the proportions of photons with a given wavelength. And so in general anything where you’re measuring a distribution of something like wavelength or frequency or energy would be considered part of spectrometry."
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nfwsui | How can a country create jobs to improve its economy? | Economics | explainlikeimfive | {
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"The government can directly spend money (build highway, bridges, airports, etc), can inject money into the economy through direct payments (stimulus checks) or incentives (cash for clunkers during 2008 recession), loans and subsidies to businesses to hire or keep people employed which means they keep spending and generating demand for goods and services.",
"The number of jobs supplied in an economy is a function of the size of aggregate effective demand. That is, businesses will employ people based on how much stuff they expect to sell, and how many people they need to sell that stuff. So if you want more jobs, you need higher effective demand. Or, you need to reduce the number of hours one person could do a job. If everyone was limited to 20 working hours a week for example, there would be a lot more jobs."
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nfxis4 | Why do humans use a high pitched voice when they think something is cute? | Usually towards a baby or a pet but could be anything cute | Other | explainlikeimfive | {
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"Babies don't speak any language so they have no way of knowing when you're talking to them or not. Knowing whether or not an adult is talking to them is critical for a baby to learn language. Speaking in an artificially high voice is a way to tell the baby \"pay attention to me now, I'm saying words to you and using body language to help you figure out what I'm talking about.\" Conversely, babies know to ignore you when you speak in a normal voice. This way they don't learn incorrect word associations because you were talking about one thing but pointing at another. This is also why you feel compelled to repeat simple words while gesturing over and over again when using baby speak - IE, saying \"thats your hand\" \"that's my head\" \"that's the door\" ect... In other words, humans have an alternate language set that they use to program normal language into babies - \"baby speak.\" Babies, on the other hand, are hardwired to pay attention to baby speak and ignore normal language. Humans use baby speak when talking to cute animals because cute animals have many of the same physical identifiers as babies (IE, they have big eyes, make high pitched noises, act clumsy and stupid, ect...). Those physical identifiers trigger you to try to program language into cute animals and so you use baby speak when talking to them. In essence, humans use baby speak when talking to cute animals because a pattern recognition error in your brain causes you to identify them as babies, causing you to enter a state in which you feel compelled to teach them language.",
"It gets their attention. I believe (I would need a source check) that babies and pets are more sensitive to higher pitches, and thus react more to them. It also helps make an association of \"high pitch=friendly and happy\" without them needing to understand the particular words used.",
"One other point nobody's made: Babies are smol. Smol voices are, as a matter of physics, higher-pitched than bigfolk voices. And humans have some amount of \"mirror what the person I'm talking to is sounding like, and doing\" also evolved into their brains, as the mirror neurons that let us realize other people are people, and understand what their expressions and actions might mean, leak through into our own actions. So when you're talking to a baby, the high-pitched is coming, in part, because the baby itself is high-pitched compared to older folk. Happens with children too, though not to such an extent, especially with that syrupy sweet \"fake\" voice some adults condescend to them with. Ditto puppies and kittens vs cats & dogs. Etc. --Dave, and we're also a bit programmed to know that something with a big head, big eyes, big paws, and small body/tail, especially a wobbly one, is probably a baby of its kind. Thus why chibi are drawn the way they are."
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nfxyjv | Law of thermodynamics? | One of the laws of thermodynamics states matter cannot be created nor destroyed. But 1) what happens inside black holes where nothing escapes?? And 2) if the universe is expanding then that means more matter is being created to fill in the space?? Or am I missing something??? Are there exceptions to the rule?? | Physics | explainlikeimfive | {
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"When matter falls into a black hole you can't interact with it anymore, but it's still there--you can tell that because it increases the black hole's gravity. It most certainly is not \"destroyed\". As for space expanding, it's the empty spaces between the matter which is expanding, there's no additional matter being created.",
"Others have talked about the mass of black hole. But I just want to point out there isn't a law of thermodynamics that says that matter can't be created or destroyed. We create/destroy matter all the time. It's what happens in nuclear reactors. Also the sun. The First Law of Thermodynamics *does* say that in an isolated system total energy is conserved (where energy includes work, heat, matter).",
"The laws of thermodynamics do not state matter cannot be created or destroyed. It states energy can't be created or destroyed. In nucelar fission and fusion this effect is used. Its called mass defect. Basically if you fuse two light atoms the created atom has less mass than the two combined. The lost mass is transformed into energy. Likewise if you take a heavy atom and split it, the newly created atoms have less combined mass than the original one. Again the missing mass becomes energy.",
"The matter that goes inside a black hole is not destroyed but added to the mass of the black hole. The universe is expanding but that just means that the space between everything is getting larger, but the ammount of energy is still the same."
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nfyqvr | How do sail boats actually get to their destination and not just blown in some random direction? | Physics | explainlikeimfive | {
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"These all touch on parts of the correct answer, but they are missing the crucial component - the keel. The keel is a big weight that hangs off the bottom of the sailboat. The wind on the sail tries to knock the boat over, the keel opposes that force, which allows the sideways force of the wind to translate into forward motion. A boat with no keel will just be blown sideways across the water and cant go in any direction except the direction of the wind. A boat with a keel can travel upwind to about 30 degrees either side of the wind direction. The opposing forces of the wind and the keel make this possible. Sailing upwind is more uncomfortable and less efficient than sailing downwind and the most efficient point of sail is actually moving about 90 degrees to the wind direction. It allows the fastest speed over ground and most comfortable seas conditions.",
"The sail is turned directly to the wind, to capture as much of its kinetic energy as possible. In relation to the boat, that wind will have a sideways component and a forwards component. The hull of the boat is streamlined to move forward, so the forwards energy is more easily translated to forwards movement while there is a large resistance to push the boat sideways. If the direction of the wind is coming from some direction from the direction you want to head you have to turn to the side so that it is coming more from behind you (tacking), so you are zigzagging across the wind in the direction you want to go",
"Some really cool physics that humanity has been using for thousands of years. Sailing downwind is fairly straight forward. Wind pushes you. Use rudder to steer. & #x200B; Now sailing upwind is where it gets really neat. It is impossible to sail **directly** into the wind. Say that where the wind is coming from is 12 oclock. If you sail at 2 oclock, you can go upwind, albeit not in a straight line. You can then switch to 10oclock, to make correct some of your horizontal distance you covered. Your net distance traveled will still be upwind. Repeat this enough and you can sail in any direction!"
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nfzvx9 | why does cigarette smoke odor linger much longer in a house than weed smoke? | Other | explainlikeimfive | {
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"Here’s a Reddit post with answers for you. URL_0 Tldr; most people are saying it’s the amount of each being smoked. People that smoke cigarettes might smoke 1 pack a day (~20g). People that smoke weed might smoke an eighth a day (3.5g).",
"Not an expert, but likely it's due to the tar content and the way nicotine bonds to it, and in turn, bonds to surfaces. As a former smoker from a family of smokers, it only takes a few cigs to turn a new home or car into a stankfest for a long time.",
"It's the fixative effect. In brewing we talk about it in terms like light notes, what you smell when you first open it, or spirits, what you smell at the end. The light notes are more volatile chemicals, escape more quickly, the heavy notes are chemicals that take longer to release. Now with this analogy, I'm referring to stuff entrained in a liquid, the whole thing will evaporate eventually, but with smoke it's not quite the same. It's similar enough to paint a picture though. You smell the cig longer because the chemicals in it become fixated on everything the smoke touches and release from that bond more slowly over time. That sweet cigar smell? The light note. The crap you smell the next day? That's the heavy note. Some comments here saying it's the paper, it's not. Burn some paper, it won't linger long, aside from your burn bucket. It's the tobacco. Also, people smoke weed in joints, kinda requires paper. It's important to note that predicting a chemicals fixative property is not intuitive. In gin production, the fixative nature is usually controlled by the alcohol content, and little changes in just ABV can swing the smells. It's more of a thing where the smells are the product of circumstances where you have a lot of unique variables, temp, time, other chemicals etc. Simply put, some of the aromatic chemicals in cigarette smoke become fixated to surfaces longer than those found in other plants. They are different chemicals, and more importantly, exist in different ratios. Also, One little thing I've noticed as someone who's raised tobacco and hemp. Tobacco has nowhere near the oil content as cannabis. Tobacco has a fraction of a percent on dry weight of the oil, where cannabis can have like 15% of it's total weight be oil. That's partly why I smoke a pack a day of pall malls, but just one joint. Now, some basic chemistry to answer the next question here: Why do things stick together at all? ...it's magnets. Don't laugh, this is eli5 and it's my best answer. Magnets have a positive end, and a negative end. Like ends repel, and positive and negative attract. Chemicals also have charges, and the bigger it is, all of the little pieces can have different charges. Some chemicals become just like little magnets, with a pos and neg ends. These will stick together n line up like magnets. Water is one of these. Everything that dissolves or mixes with water does so because of this little magnetic effect, lining up n sticking together. If any two chemicals stick together, at all, it's because of this. What about chemicals that don't make little magnets? Depends, but we break most things into two groups: aqueous, which means it dissolves in water, and organic, which does not dissolve in water. Organic material is mostly stuff like oil and fat. Mix oil n water n they will separate. They are not alike. Like dissolves like. So all organic stuff dissolves well with all organic stuff, and all aqueous stuff dissolves well with all aqueous stuff. Ok back to cigarettes and weed and fixating aroma. The smells in most plants, the pleasant ones, are organic terpenes. They dissolve into oils, and oils dissolve into them. I have no clue what becomes of the whole thing when it gets burned, whats in the smoke it produces, products created, etc. I just think it's interesting the one with more organic oils leaves less heavy notes than the cigarette does.",
"I know for a fact that if I smoke a cigarette inside, the smell will stay much longer, but if I smoke weed mixed with cigarette the smell will stay for a much shorter duration"
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ng0ai8 | How do you know if an alcoholic beverage is better than a different one in taste? | Other | explainlikeimfive | {
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"Better taste is subjective, it's better if you enjoy the taste more. For example I find a pint of Doombar much better tasting than a glass of white wine, it doesn't mean other people would agree and there's nothing wrong with someone completely disagreeing with me."
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ng13zz | how do you solve the liars paradox? | Other | explainlikeimfive | {
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"Are you referring to somthing like Pinocchio's \"my nose will grow now? Or are you asking about the two guards and two doors puzzle. One only tells lies and the other only tells truths.",
"There are different ways to see the liars paradox. Some say: \"I am lying\" is equivalent to \"it is true that I am lying\" which means \"this statement is true and this statement is this false\", which is not a paradox, but simply a false statement. Others simply say some sentences can be neither true nor false. Others maintain that true or false is not a binary concept, and that this particular sentence is 50% true and 50% false. And so on.",
"There are several competing resolutions, but I favour Arthur Prior's solution. He argues that statements include an implied clause \"this statement is true\". Thus the statement becomes \"this statement is true and this statement is false\" which is self contradictory."
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ng19ax | what is different in the brains of people with autism to that of those without autism? | I have PDD-NOS, diagnosed at four, but what exactly is different from those without autism? And what are the differences between the different sorts? Also, since it differenciates between people with the same type too, how does that work? And how is it diagnosed?( i cant remember) | Biology | explainlikeimfive | {
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"From what I have read, the brain functions “differently”. Certain parts of the brain are more active than others. There may even be certain chemicals that are more or less activated when compared to a brain without autism. That could explain why some people have very strong intellectual skills but lack social skills. The part of the brain that handles math problems, remember details, etc... could have a faster frequency speed & lower amplitude measurements. And the opposite for the part of the brain that processes social skills. These are questions that researchers are still trying to explain. But since autism is a spectrum, the “levels of difference” can vary. I have read that some people are using LENS neurofeedback to measure frequency & amplitude and help improve brain functionality since it provides information via EEGs.",
"Autism isn't a single disease. It's a spectrum of conditions with impaired communication and behavior. So there's no specific thing wrong in the brain in regards to the condition as a whole. It's like cancer - leukemia, liver cancer and brain cancer are all very different individual diseases. PDD-NOS seems to be a catch all for any observed Autism that can't otherwise be specifically diagnosed. This is like having a car that is driving slowly but you can't determine why it's driving slowly. You know that it is driving slower compared other cars of the same model and you've checked the obvious things like tire punctures, correct gas in the tank, air filter, ECU, spark plugs, coils but you can't yet determine what's wrong. Unfortunately unlike cars it's not that easy to bring you into the shop turn your engine off, take your engine head off and rumble around inside or swap out coil packs."
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ng231m | Why do casinos allow pofessional gamblers play in their tables? | Wouldn't it be in the casinos' best interests to *not* let them play? And more than that, they usually seem to offer comp suites, upgrades, and all kinds of other perks. *Why?* | Other | explainlikeimfive | {
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"Gambling is rigged in favor of the house. Anyone is guaranteed to lose money in the long run. Professional gambling is really more of a tax designation than a profession. Exception here is really poker games played against other players, not played against the house. Poker games have enough of an element of skill that very skilled players can come out on top in the long run. Casino makes their money on poker by taking a percentage out of every pot (known as a rake), or an hourly (sometimes every half-hour) fee for the privilege of playing. The skilled players can overcome the costs. So in any case the casino maximizes profits by having people play as long as possible and the higher the bets on most table games the better. If you're really good at counting cards in blackjack, there's some potential, but casinos are really good at countering this and the best card counters will actually be asked to leave. Edit to clarify: Gambling's not really \"rigged,\" they're fair games but they're rigged mathematically so your payouts are under the true odds and you can't win in the long run.",
"There is a distinction between wealthy people who bet large amounts on casino games (roulette, craps, blackjack), people who are trying to make money on blackjack, and professionals who typically play poker. Having high rollers (the first group) is good for the casino because those people lose a lot of money. Also having wealthy people swanning around makes the casino seem somewhat glamorous. The second group can actually be good for the casino. The perception that blackjack can be beaten encourages punters to try, and lose their money. That said, casinos work hard to prevent people making money from blackjack, including banning people who manage it consistently. The third group are not gambling against the casino. Casinos will host them as a form of advertising (e.g. televised tournaments), or simply take a cut to host games.",
"Because Casinos are generally not skill based. Any game where the casino actually bets it's own money is either entirely or to a very large degree luck based, and always has a house edge (meaning in the long run the house always wins), so it doesn't really matter if the person playing is the worlds best gambler or johnny nobody. The casino wins either way. And the games that do actually involve a decent amount of skill, like poker, are player v player games so the casino loses no money to the winner, and makes a profit of the drink and food they buy."
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ng2kgc | How does an intoxicated person’s mind suddenly become sober when something very serious happens? | Biology | explainlikeimfive | {
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"When a serious event happens, your adrenaline rush kicks in. It doesn't sober you up but acts as a strong stimulant which can overpower the depressant effects of alcohol for a duration of time.",
"It doesn’t. A person may feel a bit less intoxicated if in a serious and/or life threatening situation because of adrenaline or similar hormones, but they are still intoxicated. They will still be suffering from the effects of intoxication. The only way to actually “become sober” after consuming a large amount of alcohol is to allow enough time to pass for your body to process it, which is a few hours at the minimum.",
"Adrenaline. You don't become \"sober\" you just stop having fun because something bad happened. People colloquially say \"it was sobering\" but that just means the fun ended - not that the influence of drugs has suddenly worn off.",
"Just because I haven't seen this pointed out very well: You don't \"Become Sober\" when something serious occurs. You are still drunk/impaired by any and all metrics. While adrenaline will narrow your mental focus to the problem at hand, remove the sense of fun/euphoria, and decrease your response time, it is still relative to the level of chemical impairment you are experiencing.",
"Adrenaline, that's your body's \"something serious happened\" signal. It gets more blood moving and mainly makes your awareness and senses better. So they're still drunk the brain is just a little too drunk to know how drunk it is, and the increased awareness makes the brain suddenly feel more sober.",
"It doesn't. Adrenaline makes you *feel* awake and alert. This gives the illusion that you have \"sobered up\" because your body is using these things as a gauge of drunkenness. However, the effects of alcohol are still fully present. This is actually one of the dangers of mixing stimulants and alcohol - rather than directly counteracting each other, they actually both affect you simultaneously. So you end up both stimulated and drunk, which is not a good combination.",
"For the most part, you don't. Suddenly *sobering* up in a movie cliche. But it isn't baseless. When something serious happens, your mood will rapidly and drastically change, as it would when you are sober. As such, your intoxicated behavior and the manifestation of your drunkenness will change with it, and alcohol tends to amplify your moods. Let's say you're having fun with your friends, when suddenly you witness a car crash. Sober, you might go from smiling to flinching. Drunk, you'll go from sloppy dancing to screaming. Same mood change, different manifestations of that mood.",
"ELI5: When something serious happens, your body unlocks it’s hidden Red Bull fridge and force feeds you the equivalent of a dozen of them, to expected results.",
"I once had E at home and as i was peaking, my mum called me for dinner. At first i pretended to be sober, sat down at dinner table zoning the fuck out. Mum then calls me to the kitchen to cut up a pineapple. I couldn't think and that request was random! but in efforts to look sober i got up and went to the kitchen.thinking back..i must have been crosseyed. As my mum handed me the knife, for some reason i had a sudden wake up call that i could hurt myself or worse someone else. My vision focused and my hands steadied and my mind went clear. Following that whilst buzzing different, i managed to prep the pineapple and sit down and eat a meal...Whilst not having an appetite?? After dinner and back to my bedroom. I had a deep breath, relaxed and my E high returned with a vengeance. Was that adrenalin? I always thought i had super self control powers then.",
"I have one very visceral memory of this happening. I was so close to pass out drunk (but I didn't care, because I was just camping with friends and family) But then a buddy got into a big fight with his girlfriend, and was about to drunkenly drive his dirtbike all the way back home through the dark uneven Forest road. (And if he got through that it would've been highway) I immediately felt myself sober up and another friend and I stayed up for hours after everyone went to sleep talking to him and keeping him from leaving. (He was very persistent, but we got him to go to bed eventually.)",
"Your environment becomes more stimulating than the drugs and every part of your brain becomes focused on the task at hand. The rush of neurotransmitters and activity in that moment suppresses the effect of the drugs.",
"A lot of intoxication is distraction. Get somebody's attention, and they're gonna seem less distracted. An emergency will get your attention.",
"As someone who is sober at bars and drinking events, when other people around you are drunk and having a great time, it’s very infectious. I feel like I get a bit of a contact high just from being around them and feel a little, not drunk exactly, but giddy and energetic. You don’t have to actually be drinking to enjoy the fun, drunk vibes.",
"Over a year ago I had been drinking and driving. (I know shame on me) I had been drinking for over 24 hours so lord knows I should have never got behind the wheel. As I was pulling out of a parking lot I stalled my car on accident. That warrented a police officer to pull me over. I knew for a fact I'd be going to jail so my heart start racing. My anxiety sky rockets. Now I have a speech impediment and a accent. Any time I speak to cops its a issue in the first place. The cop takes my info and asks if I've been smoking. Wait what. The cop was convinced I was high on weed. I dont smoke. They pulled me out to do the sobriety tests. I passed each one which frustrated the cop. He then took me in based on my speech issue. I was drunk so I mean fair. I felt and acted sober during this whole 30 min process but as soon as I was put in the back of that cop car I felt drunk and began acting like a drunk. My alcohol level was .17. He actually didn't hold me for the night. He gave me a dui and let me go home. Im now 11 months sober. Glad I quit. I dont know how it works but its insanely weird that you can feel and act sober for a bit if something serious happens.",
"Adrenaline takes over your subconscious \"willingness\" to succumb to the effects of alcohol.",
"Many people saying adrenaline, but it’s more likely a similar chemical, norepinephrine (a.k.a. noradrenaline) being released in the brain.",
"It doesn’t. But... your sympathetic nervous system kicks in to overdrive during crisis. This involves a big wave of drugs that the body gives itself. It counterbalances things.... sometimes...",
"I remember in college we had a Halo 3 tournament where everybody had to get drunk before it started. We drank more than we ever had that night and I don’t remember feeling a thing. The stress and intensity made everybody laser focused even though a few of us should’ve had alcohol poisoning. The hangover was real the next day.",
"Everything I read in the thread is complete bullshit. Intoxicated people do not suddenly become sober. The alcohol continues to affect the brain and body until it's out of the system. Focusing your attention briefly does not make one sober. Neither does coffee or a shower. People might feel like they are more sober in a crisis or when given an adrenaline rush, but it's short lived and does not represent being sober.",
"I had a hit and run collision with 3 different cars while blacked out. With each collision I instantaneously came to for a brief amount of time before what felt like drifting back into a dream. When the car stopped from mechanical failure, I came too and cried that it all was truly a dream as I heard sirens approaching, pinching myself to wake up. Then I drifted off again. Terrifying doesn’t begin to assess the damage of that night. Thank god I gave up alcohol.",
"The hippocampus is the portion of your brain that is responsible for writing and accessing memories like a computer hard drive. When you intoxicate yourself to an unsafe level your brain turns this off in order to preserve it from incurring long term damage. When your flight or fight response kicks in and your brain initiates an adrenal dump to get your ready to act it also basically yanks off all the safety mechanisms in case you need to remember how to hot wire a car or what part of the animal to stab with pointy stick"
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ng3211 | if skin constantly sheds and produces new cells, why does it deteriorate in appearance with lines/age spots etc over time? | Biology | explainlikeimfive | {
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"Skin consists of multiple layers. Think about tattoos. The ink is in your skin, but it doesn't slowly get pushed out. It fades over time due to the ink breaking down. The outer layer performs the shedding function, but the middle/lower layers do not. They are what wear down over time and cause spots and lines."
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ng3gjx | How are mountains (or mountain ranges) formed far away from plate boundaries - is it a sort of crumpling effect? | Earth Science | explainlikeimfive | {
"a_id": [
"gyop8pa",
"gyonnck"
],
"text": [
"There are a number of ways mountains can form but the biggest mountain ranges are formed near plate boundries. However a geologists definition of what is near might differ from what you consider near. For example while it is obvious that the Sierra Nevada is forming due to the Pacific Ocean plates colliding with the North American plate due to its proximity the plates interacted differently tens of millions of years ago and the same process took place much further inland creating the Rocky Mountains. Other mountain ranges such as the Appalachians are currently far from active plate boundries but were formed during previous collisions, in this case between North America and Africa. But of course there are exceptions such as Hawaii which is not near any plate boundries but still have a cute little mountain range going.",
"Yes. Take two sheets of heavy paper ans push the edges together on a flat surface; they’ll start buckling somewhere towards the middle if you hold the edges down."
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ng3m17 | How did authorities enforce speed limits before the invention of radar? | Technology | explainlikeimfive | {
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"text": [
"Distance over time. If it takes 10 seconds to travel from point A to point B while traveling the speed limit, and a vehicle goes that distance in less time, they're speeding. If the distance is known, the speed can be calculated based on the time, or you can pre calculate a few common overages, like 5 over would take 7.3s etc.",
"Typically it was eyeball whoa he’s going way too fast or painted lines and a stop watch. There is a B & W Andy Griffith show where Andy & Barney pull over a woman. “Andy and the Woman Speeder”",
"A very common technique is to use a stop watch and measure how long a vehicle takes to travel a measured distance. This is still very common as it allows measurements to be taken from far away and from the side. So the police might hide on the other side of the valley from the road or in an airplane and still take accurate speed measurements. Even speed cameras can do this either by measuring the time the vehicle takes to trigger two sensors on the road or even how long the car takes to pass between two speed cameras along the same road. This is also a technique which is safe from radar detectors and radar jammers.",
"There is also the pacing method. By matching the your car from a consistent distance and observe the reading from the police car’s own speedometer.",
"Pacing - Just follow at the same speed and read your speedometer. VASCAR - Invented in 1966, it used time, distance, and speed inputs to compute the target's speed. There are several modes. If there are markers of known distance, you just input that and use the stopwatch function. Can be done from car or aircraft. Or, say you spot an oncoming car speeding. As they pass a landmark (sign, tree, etc) you hit one toggle. As they come directly opposite you, you hit another toggle. And as you reach the landmark, you hit it again. It reads the distance you just drove, and knows the time the car took to traverse said distance. Then computes the speed."
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ng4gw4 | Why do meat near the bone and meat bone-in have more flavor? | Does it depend on the type of protein or cut of meat? | Biology | explainlikeimfive | {
"a_id": [
"gyov1xp",
"gyprz42"
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"text": [
"Bone marrow makes red and white blood cells as well as leaches minerals and fats into the muscle surrounding it, so the meat closest to the bone is the meat that’s getting “fed” the best by the body",
"I like r/ronohosie's response, but also, meat close to bones doesn't get as much rigorous use as the 'big' muscle meats, like shoulders, loins, and rumps. That causes these meats to be more tender and have more fat. When animal meat is cooked fats, proteins, and sugars react and combine as part of a type of chemistry called \"Maillard Reactions\". Human senses are highly tuned to consider Maillard reactions *absolutely freaking delicious*. For example, Maillard Reactions are responsible for - caramel, bread toasting, steak browning, bacon sizzling, French Fries/Chips getting that deep brown color, etc. In a nutshell, if food turns brown while cooking, that's a Maillard Reaction. (This is different from food turning brown for other causes, like apple slices, that's other stuff)"
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ng4meq | Why aren’t our hands, arms etc perfectly still or accurate? | Biology | explainlikeimfive | {
"a_id": [
"gyoyewo",
"gyotlv1"
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"text": [
"Your muscles aren't single, cohesive units. They're organized structures of millions and millions of individual muscle cells acting in a coordinated fashion to exert force as a unit. This means there's considerable variability at the cellular level in terms of what those cells are doing and how they respond to nervous signals. One errant nerve impulse can fire off a small group of muscle cells that produces a twitch or movement that you can feel. It's even more variable when it comes to using your muscles. Suppose you're threading a needle, something that requires very fine motor control. Your brain is sending nervous signals to contract and relax the muscles of your hands and arms in order to complete this task, but at the cellular level there are millions of muscle cells all working in different rhythms as they cyclically activate, fatigue, deactivate, and repeat. The finer the motor control required, the more apparent this variability is.",
"Most of the time it's nerve reactions. Sometimes when your nerves get triggered by s touch or sensation they have s slight reflective tremor or flinch."
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