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77zbnv | Why do drugs that cause serotonin and dopamine rushes mess up the brain and can cause depression after withdrawal but having sex does not? | Crystal Meth has been described to giving an euphoric sensation "similar to an orgasm", but natural sex does not cause withdrawal effects, depression even though these chemicals are also released. URL_0 | Biology | explainlikeimfive | {
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"Because you can do a lot more Crystal Meth than you can have sex, and there is a lot of other toxic crap in Crystal Meth that will mess you up.",
"ELI5 version Drugs make your brain push these chemicals much harder than normal. To the point that your brain has trouble balancing everything out again. The tiny bit you get from sex is easily balanced out again versus the massive dose released during drug use. When you're brain chemistry has been altered to that degree, you get things like depression and withdrawal. Also, people do sometimes get addicted to that rush from sex.",
"Most people who get fucked up on meth for instance, just take too much, push their bodies beyond the limit and then pay the price. if you use a drug responsibly you will (most likely) not suffer depression and mess up the brain, in fact many \"euphoric\" drugs and \"hallucinogens \" can be used to have the exact opposite effect to \"messing up and creating depression\". Also when taking a drug for recreation, it is invariably a massive dose compared to the miniscule amount produced by the body or brain for a natural effect."
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77zd5k | What exactly is a sneeze and why do we all have a different sound? | Biology | explainlikeimfive | {
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"Sneezing is your body trying to clear your upper airways of debris and other stuff that shouldn't be in there. As for different sounds, I would assume that it has to do with air rushing over our vocal cords. And since we have different vocal cords and voices, our sneezes would sound different too. (This is just an educated guess) Also, some people I know like to be dramatic when they sneeze, whereas I try to cover my sneezes so I'm sure that has something to do with it too."
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77zvhd | Why are research papers written and published in a two-column format? | Other | explainlikeimfive | {
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"One of the reasons I have seen it that way is because of the frequent inclusion of small tables and pictures. If you had traditional page width text, you would wind up with wasted space because of these things, or you would have to cram more tables/pictures in one row, even if one of them isn't referenced for another page. One could argue that, since most papers aren't actually printed, space isn't an issue like it is for print versions of journals. But that would be extra guidelines for editors and overall extra work.",
"i have no idea but as a graphic designer i can tell you that smaller columns of text with a shorter amount of words per line (like a newspaper) is easier to read and format. i know you and many people prefer to read one solid block of text, and i don't know why this is, but i've always been told that having more than 50 words per line is a big no no. The only time i would do it is if i was writing a paper for a class in school or something and was formatting in Word but if i created a book of research papers or something I might be formatting in a more powerful program like InDesign and choose to make it look fancier. I could be completely wrong and it could just be a \"it's two columns because that's the way it is\" but i can't help but feel like it has something to do with it actually being formatted to look more respectable -or published in some sort of larger format maybe?",
"Part science, part tradition. The science part, as others have mentioned, is line length. Research shows lines that are too short or too long reduce comprehension. While there isn't one exact size, less than 50 characters per line seems bad, while more than about 80 also seems bad. If you look at professionally typeset material you'll find 99% of it with lines around 60-70 characters long. The other half is tradition. Scientific papers are typically typeset \"densely\". That is relatively small fonts and figures. The idea is to fit a lot of information on the page. The smaller font size would make one column's lines way too long, so the two-column format makes sense. Newspapers, with large pages and a desire to be information dense use small fonts with many columns. Books, which are designed to be easy to read use single column with larger fonts. A good introduction (although far from gospel) online is URL_0",
"Graphic designer here. There is a certain width of s line that works best for reading. Having the text be the width of the page causes your brain to work harder to complete and comprehend the line. Breaking it into two columns makes it easier for comprehension Imagine the two extremes, like if the whole paper were written on in line. Eventually it’s going to really bother you. The same is true if it was one word per line and caused you to read downward. Both are just not natural for our own brains to be comfortable with. I can’t speak for any particular journal, but typically two or three columns on a page are in the sweet spot for reading comprehension. As for your comment on white space, just know that often times white space is a good thing. Good design doesn’t mean filling in everything. Often times it’s just the opposite; letting things stay empty so that what IS there is understood or followed more easily.",
"A quick correction: Scientific papers are often published in a two column format, but are almost never written that way. We write papers in a normal Word document, send them to the editors in Word, the editors send them to the reviewers in Word, we make needed changes in Word, and then finally someone at the journal reformats everything into two columns.",
"It depends on the journal. Some like Nature and Science use the multi column format, while some others do not for example the journal Sensors. I often see a mix of the multi column style and single column style. I agree that I prefer single column style as I mostly read them on screen and find it a pain in the butt to have to zoom in to read the tiny text in multi column papers.",
"I publish in Economics journals and have seen editors discussing the possibility of switching the format. There are a few things that matter: 1-Design. As some designers have mentioned, good design avoids lines getting too long. One reason for that is that when reading a short line you can kind of see the beginning of the next line with the corner of your eye, so it makes it easier to skip to the next line. Ever started reading the next line, only to realize you have already read that one before? A lot of good design, such as choice of fonts, size of margin etc., is about making it natural and effortless to keep your sight at the right place. 2-Cost of printing. In the old days, journals were all printed, and printing wasn't as cheap. Being efficient with the use of space was a good way to bring costs down. One way to be more efficient is to use a smaller font. But if you use a smaller font and keep a single line, the line gets too long, or the margin gets too large. Hence they used the double column, which is now regarded as a more classic/vintage look. 3-Things that are not text. In economics, the main issue with the short space of the double column format was having to break longer mathematical formulas, making them sometimes hard to read. Because of that, there's recently been more of a move toward single column. This is also relevant for pictures or tables. All of these things have become increasingly prevalent or easy to make with our recent technology, so they are more relevant than they used to be. Things that are not text usually have a \"natural size\" and ideally the size of the text column would be the same as the pictures size (with a single column) or about half of it (for double column). In Nature and Science big pictures are often a thing, so that gives an argument for having larger columns (not a particularly strong argument, in my opinion, but still). In my opinion, for text-only the double column format is superior and much easier to read. But as soon as you're breaking the text often with tables, formulas, or pictures, the single column gets better.",
"It strikes me as arising from a journals already having their LaTex macros and formatting templates already set up and there’s no incentive to change them.",
"Narrow columns are easier to read as requires less effort to track which line you’re on. For the same reason when using a large monitor I use a less-than-full-screen browser window to make text columns narrower. I agree that panning around a PDF of a two column journal is a pain but I prefer that to wider columns.",
"Manuscripts are in fact sent to the publisher in the traditional block text double-spaced format and converted downstream by the journal(s) into their respective single-spaced two-column formats. 1. Because if you insert a figure that takes only half the horizontal space and try to fill the rest with text it's ambiguous if the first line on the page begins under the figure or next to the figure. 2. It was very common before electronic print to squeeze memos and advisories into journals like a mass email. But these 'articles' were only 1/6th a page. If you try formatting an article that small into un-columned page with other articles and figures you'll see that it looks absolutely terrible. Give it a try. Newspapers do it too."
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77zw1e | Why are details of deadly chemical compound easily available on the internet? | Chemistry | explainlikeimfive | {
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"While the method is easily available the skills, raw material and equipment are not readily available. E.g. hydrogen suphide needs pure hydrogen (so you need a source of that) and molten elemental sulphur at 450 degrees C or collection and concentration of a low level gas products from bacteria. Neither of which are easy to do.",
"Why is any information available? Think about how shit the human race would be if we all had to start from scratch instead of learning from those who came before us. Even when studying chemicals, knowing the process that leads to deadly compounds could save you from discovering those compounds were deadly the hard way."
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7803go | Why is human's average reaction time slower than other animals? | Biology | explainlikeimfive | {
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"The difference comes from how our nerves are structured. Most of your neurons have a coating around them called a myelin sheath. This sheath is divided into segments, and it's purpose is to increase the speed of any signal traveling through the nerve. It's like a speed booster that lets the signal jump really quickly between the segments. Animals like cats have more efficient coverings on their neurons, allowing signals to travel faster than ours. Their bodies use substantially more resources to create and maintain a highly-effective conductive layer over the neurons. Their nerves also have more machinery dedicated to moving those signals as fast as possible. When we say \"cat-like reflexes,\" it's literally because signals from their bodies reach the brain (and vice versa) way faster than ours. If the signal was carried by a person, ours would be a dude on a bicycle while cats have the Jimmy Johns delivery guy. As humans evolved, we didn't need to prioritize reaction time, and it wasn't selected for. Other animals rely heavily on quick reactions both to hunt and survive. That's not as much of an issue for humans."
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7804f8 | What defines the shape of some drinking glasses to correspond to a specific beverage? For example, wine or scotch glasses have slightly different sizes of the leg and the part that holds the drink. Is it a historical matter? | Other | explainlikeimfive | {
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"This is a fun question that we’ve spent a lot of time studying. I’m a sommelier with a specialty in whiskey. The thickness of the glass, the shape of the bell, and the stem all play rolls in how the smell gets to your nose and at what temperature. The Ol’ Factory being a major part of how we “taste” things. There’s a couple of things to consider , however, and the most important thing is that “individual tastes can not be disputed” so one person prefers a glancairn whiskey glass while the other prefers more of an open bell top cognac style whiskey glass. The open bell allows for more of the alcohol to escape letting you not get face fucked with high proof booze but also some of the aromas escape with it. I teach people how to smell “around” the alcohol of whiskey all the time and generally prefer a closed bell copita style glass for whiskey. Wine is a whole other animal and I can assure you that even the most trained noses only need about 2-3 different style glasses and all the rest are just for marketing. Go on Riedel’s website and they’ve got a different glass style for just about every varietal or French wine region. I’ve narrowed my preferred drinking glass to generally be in the burgundy style for most whites and softer reds and I tend to lean towards the Syrah/Rhone style glasses for reds.",
"For the most part surface area and if its surpose to be smelled or not. Glasses on stalks, such as wine glasses. You are surpose to grab the stalk so you dont leave fingerprints on the glass. While cognac glasses are surpose to rest in your hand so you heat it up and evaporate the alcohol (and the released smells that comes with that) when smelling it.",
"Depends on the drink, some are just aesthetic, but whiskey glasses for example are a tulip shape to help funnel vapours a certain way to affect how you smell it, which effects the taste. I believe same with wine glasses but I'm not a huge wine person so i may be wrong. Sometimes it's aesthetic, and sometimes it's to change the experience. You wouldn't really wanna drink a draught beer out of a dainty little cup, as much as you'd want to drink a nice glass of tea out of a really beefy thick mug."
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780x48 | Why do towels that feel so rough on the skin dry you so much better, but towels that feel soft don t dry well at all? | Chemistry | explainlikeimfive | {
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"Fabric softeners that make towels nice and fluffy also make them slightly more water proof so they tend to absorb less efficiently.",
"Part of roughness means there's more highs & lows in the towel fibers. That increased surface area allows more area for absorption and therefore allows for better drying. You could try to make a towel soft by increasing the density of fibers/yarns but then if you increase it too much you just approach a solid surface meaning there's less surface area for absorption again. I'd say in reality there's a balance in the type of fibers/cloth a towel has which determines its softness/absorption capabilities and your actual fiber/yarn count. There are very soft towels (supima cotton) which can be [extremely good at drying]( URL_0 ). You don't necessarily need to sand your skin to get a good towel. I personally use the Pottery Barn towels that Sweet Home recommended a few years ago, and they've spoiled me. I end up hating most towels at hotels unless I stay at a nice place. Even the JW I stayed at a few months ago had towels that felt like sandpaper.",
"Fabric softeners coat the towel fibres with a film that isn't very water absorbent, which makes the towel feel softer, but it won't absorb (dry you) as well. Generally, towels should be washed with just detergent at a relatively high temperature (60 degrees celsius+), and tumble dried to fluff up the fibres/threads to ensure maximum surface area. The drying in a machine is important, as towels which are air dried will tend to have the threads clump together which creates that rough feeling too. Lots of hotel towels that feel rough are just using dense cotton designed to last longer, or they are overly worn and the threads are short. Like with bed sheets, towels are one item where it's worth investing a few extra bucks to ensure good quality and they will last way longer than a cheaper product using poor materials. Egyptian cotton is considered one of the best.",
"In most cases, it probably has to do with fabric content. 100% cotton towels are very \"thirsty\" and dry well, but towels that are part polyester (or another synthetic material) and woven with thinner fibers will feel softer to the touch, but not soak up water the way cotton does. The quality and length of the particular cotton, as well as the way it's woven, also factor in.",
"Also while we are at it, can someone please tell me which of the two are better for your skin?",
"It partly depends on how the towel is made. Terry cloth towels have loops that will wick away moisture on contact. Sheared towels or microfiber type towels are cut and it's harder for the strands to absorb moisture when you rub it on your skin."
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781m2w | Why does "trickle-down" economic philosophy not work? | Economics | explainlikeimfive | {
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"In simple terms - because there is an upper limit on how much the rich will invest/spend. The core concept of \"trickle-down\" economics is that the rich invest and spend money and that drives the economy forward benefiting everyone. In practice however, at some point the rich have invested in everything they wish to invest into, bought everything they want to buy, and are left with nothing to do but save. Contrast that with the lower and middle class consumers who for the most part spend every dollar they have. Give a $1,000 to a rich man and he might spend and invest $800 of it. Give $1,000 to a lower class person and they'll spend every single penny."
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781y2l | BigMacs have two bottom buns and a top bun. What happens to the leftover top bun? | Other | explainlikeimfive | {
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"They have a single large bun that's been cut into 3 pieces. They are made this way & there is no wasted bun involved. If look at one, this is immediately obvious since the middle bun does not have a crust on either the top or bottom."
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781z5n | If you "shut off" the gravity like in movies would you spontaneously start floating? Wouldn't you need to push off something to do that? | Physics | explainlikeimfive | {
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"Honestly I have no idea, but could it just be the slight bending of their legs giving them the \"lift\"? Sudden weightlessness may make them push off in an attempt to regain balance?",
"Both. You wouldn't automatically float, but the slightest twitch will either send you away from the floor, or towards it, causing you to bounce off and away from the floor. It would be almost impossible to maintain equilibrium without some constant force pushing you towards the floor."
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782ji1 | How do Radio Waves for cell phone signals penetrate into buildings if light can't travel around corners or visible light can't shine through opaque objects? Wouldn't you need a direct line of sight to the tower? | Technology | explainlikeimfive | {
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"Light and radio waves are all part of the electromagnetic spectrum. They don't all behave or interact with stuff the same. Xrays, infrared and microwaves are also part of that spectrum. They, like radio waves can be reflected like visible light but can penetrate certain materials."
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782r95 | Why do clarinets overblow at the 12th, but saxophones overblow at the octave? | I know the clarinet has a cylindrical bore and the sax has a conical bore, but how does the bore shape affect how an instrument overblows? | Physics | explainlikeimfive | {
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"The bore shape is part of the issue, but the other part is that the clarinet is *closed at one end*. Any tube is going to produce harmonics: the fundamental is the first harmonic, the octave at the second harmonic, the 12th at the third harmonic, and so on. An ideal closed cylindrical bore doesn't produce even-numbered harmonics, so it can't overblow at the octave. In practice, a clarinet produces very weak even-numbered harmonics in the first (chalumeau) register, so it overblows at the third harmonic, which jumps up a twelfth. For comparison, a conical bore that's closed at one end (a saxophone) or a cylindrical bore that's open at both ends (a flute; your mouth doesn't block the hole in the mouthpiece) produce stronger even-numbered harmonics, so they can overblow at the octave."
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782rgj | Why so many videogames have the "glitching through surface and shaking furiously" bug and why does it happen? | Technology | explainlikeimfive | {
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"It's a result of a game's physics engine trying to approximate things \"bouncing off\" each other when they're trapped. So first what happens is the objects clip through each other, due to one of ten billion possible bugs or reasons. Exactly what gets 'em going through each other depends on the game. But what then happens is the game detects that these objects are touching & moving, and therefore attempts to bounce one the other way. If they weren't clipping together, this behavior would look like realistic physics. It's simplified from real physics but looks believable, so lots of games implement this. The problem? The new \"bounced away\" position is *still* clipping through the other object, so it qualifies as \"moving and touching\" again, and the game then moves it *back*, leaving it stuck in a loop."
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782rx3 | How are "scratch n' sniff" stickers made? | Chemistry | explainlikeimfive | {
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"There are tiny (microscopic) capsules filled with scented chemicals on the surface of any sort of \"scratch n' sniff\" surface. When you scratch them with your finger, you rupture some of them and release the smell."
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7830od | Why is it so hard to duplicate the taste or resteraunt food? | Chemistry | explainlikeimfive | {
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"You're probably not using the same ingredients. Restaurants generally use a lot more butter/fat and salt than you'd use at home. After that, restaurants can generally crank out more heat than home kitchens so food browns better which is responsible for creating a bunch of flavor.",
"Not sure, but I know 2 things that might actually impact the dishes: 1 - restaurants often use *way* more fats/sugars than you'd use at home. 2 - the ingredients aren't necessarily the same/the same quality Restaurant suppliers tend to have better quality ingredients for some dairy (e.g., thicker cream), meats, and produce than what we get in the grocery stores. (Although, yes, a lot of the packaged products are the same brands - just a lot cheaper and in bigger volumes). But even if the ingredients **are** exactly the same, the food you cook at home may not taste as good simply because of your perception. When you cook at home, you have to do all the work, and you're serving the food yourself on your own everyday dishes... doesn't have quite the same experience to it as eating in a restaurant, and that can mess with your perception."
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783e2v | Why do NASCAR drivers swerve back and forth during warm-up laps? | Physics | explainlikeimfive | {
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"Warm rubber grips the track better. When they're going really fast (like race speed) the friction of the tires on the track around turns is enough to keep them nice and toasty. When they're going slower, like behind the pace car, the friction level around turns isn't enough to keep them at a good temperature on its own. So they swerve back and forth to make more friction to keep the heat in them. A good analogy might be rubbing your hands together quickly to keep them warm.",
"Two reasons... To clean the debris from the tires, and to keep some heat in the tires. It's common to see them do that at the smaller tracks"
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783k04 | Why does reducing the resolution of a video consequently affect the sound quality? | Technology | explainlikeimfive | {
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"No, that isn't the case at all. Sure, if you shrink a video by running it through some program on its default settings, without understanding what it's doing, then that might be what you get out. It doesn't have to be that way. If you learn how to use a command line processor such as [FFmpeg] ( URL_0 ), you can get exactly what you want. It can recode video while \"passing through\" the audio, for example.",
"They're two different settings, **but** most video services (like YouTube) assume that you're switching to lower quality because your internet was struggling with the higher bitrate version. So they scale the sound quality back too to make sure absolutely everything fits in the pipe, per se. If you're getting fancy with video encoding tools (like the other guys described) you can crank sound quality as high or low as you want."
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783xe1 | why does sugar turn brown when melted? | Chemistry | explainlikeimfive | {
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"Sugar is a molecule made of a particular arrangement of carbon, oxygen, and hydrogen atoms. When you heat up the sugar, this adds energy to the system that can be used to fuel chemical reactions that rearrange the bonds between these atoms. Some of these compounds are dark brown in color and add caramel flavors to the sugar. Similar reactions occur in meat when you cook it and get a tasty brown crust.",
"It turns brown because of [caramelization]( URL_0 ). Now, caramelization in itself is a poorly understood process, but we know a few things about it. It is, simply put, the degradation of sugars under heat. Now, these sugars break up into simpler sugars, dehydrate, fragment into aldehydes and ketones, polymerise and undergo several other reactions. Don't concern yourself with the details of the reactions unless you want to - just understand that there are many reactions simultaneously occuring at that temperature. For the compounds we are interested in, we can broadly separate them into two categories - volatile compounds and polymers. (It's a lot more complex than this but these are the two important classes). * Volatile compounds like [diacetyl]( URL_2 ), [Hydroxymethylfurfural]( URL_1 ) etc. are released which gives caramel its characteristic smell/flavour. * The polymers (30+ carbon atoms/molecule) formed are grouped into three classes: Caramelans, Caramelens and Caramelins. They contribute to the brown colour of caramel. Clearing out some misconceptions 1. Caramelization is not the same as the Maillard reaction (browning of bread, meat etc). *The Maillard reaction requires amino acids to react with sugars, whereas caramelization does not* (it is simply the degradation of sugars with heat). They both involve browning and can occur simultaneously, on the same food base, and with similar results on the taste buds, so they are quite easily confused. 2. It is not brown because of carbon. That sort of burning requires a much higher temperature than the caramelization reaction. If you try to caramelize on too high a flame, you will see it turning black and tasting charred. That is carbon (see pyrolysis/carbonization for such reactions).",
"It's worth mentioning that it is possible to melt sugar with it remaining clear, but it is difficult because it so readily burns.",
"I had a lab report due on the Maillard reaction at 11:59. It’s because of what everyone else said. Monosaccharide sugars respond quicker than di/poly- saccharides and the reaction increases speed with increased temperature and or increased pH to make it more a more aqueous or basic environment. It’s a non enzymatic browning reaction that occurs between a reducing sugar and an amino acid with heating/ etc. ketones work better than aldoses because they are more inclined to release positive aromatic compounds while aldoses such as Xylose release compounds that smell like dirty socks.",
"A lot of whack answers in here and misinformation. First off, it has nothing to do with the Maillard reaction so ignore all those. ELI5: Think of sugar like a pyramid of Lego bricks, you start heating them up in a frying pan and start by breaking them into single bricks, this is your melted sugar. As you keep heating, your going to start melting some of your bricks that are touching the frying pan. Clearly these melted Lego bricks aren't going fit back together, maybe you can get a few together but you can't stack them like you could before and some of them might start melting together, these are your browning products and flavors in your sugar (caramelisation). If you keep heating your eventually going to burn your Lego, turning it black (pyrolysis).",
"Don't all things go brown/golden when heated.. Then black when they burn..?",
"Sugar is part of a type of molecules known as carbohydrates. At a very simplistic level carbohydrates are carbon atoms with waters around them with the generic formula (CH2O)x. For sugar x is 12 but that is not important. What is important is that if you heat sugar enough, you eliminate water molecules (think of it as boiling) and you are left with just carbon atoms (basically coal). Between coal and sugar, there are various levels of dehydration, so you go from colorless/white to black. In between you have yellow and brown, depending on how much dehydration you did.",
"As others have said there are some reactions that occur to make it brown, however there are many compounds that I work with which are nice white crystals when solids but are yellow or brown oils when liquids so a change in color doesn't necessarily mean a chemical reaction."
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784a4d | Why isn't a dimensionless number negligible in a calculation if it theoretically has no physical properties | Physics | explainlikeimfive | {
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"The numbers don't have to have a physical correspondence to nevertheless reflect physical reality. Pi is not negligible, it's a derived ratio. It's required to make the math work. It represents a relationship between certain quantities. That's the whole point of these constants - they were determined based on relationships we understand, and using them is fundamental to making the numbers some out correctly.",
"Suppose I have two loaves of bread, each of which weighs one pound. The \"one pound\" has a dimension, but the \"two\" is dimensionless. Nevertheless, it is highly important in calculations. The total weight of two loaves of bread is different from the total weight of one loaf of bread. Or, (dimensionless two) times (one pound) is different from (dimensionless one) times (one pound).",
"\"Dimensionless\" does not mean the quantity has no physical significance, it means that the value does not depend on the choice of units (dimensions) used. Suppose you have a spring, and it's 10cm long. That quantity is not dimensionless - you have to specify the unit, and it's not meaningful to say the spring is 10 long. If you measure the spring in inches instead, you get a different number. If you now compress the spring so that it's now 5cm long, then it's 50% of it's original size. Percentages are a *dimensionless quantity* - it doesn't matter what units you use to measure the length - the new length is still 50% of the original length."
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784bkl | Ninth Amendment | Canadian here. What is the meaning of the Ninth Amendment, and what are examples of laws that would violate the Ninth Amendment. | Other | explainlikeimfive | {
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"It basically allows for the possibility that the founding fathers didn't account for 100% of the rights a person has and will always have and allows for \"common sense\" interpretations of those rights so that they don't need to be explicitly stated in the bill of rights for them to exist and be real. It's basically meant to ensure the government doesn't try to restrict peoples rights to the limit of a literal interpretation of the bill of rights. So even if a law was crafted that was meant to restrict all free speech except what is explicitly stated in the first amendment, the law would fail because the 9th amendment says there may be more rights that are covered but not writen in the bill of rights. This helps keep the door open for future amendments that are meant to specify rights that weren't writen down previously.",
"It has one main purpose. To protect rights not listed. It says that just because something isn't listed in the Constitution doesn't mean it's not a right. An example of this is the right to privacy. The idea is that without it, it could be argued that only those listed are rights people have.",
"The drafting and ratification of the US Constitution was a hotly controversial subject resulting in lots of compromise. For fear of the US (or any government, really) devolving into Tyranny, certain representatives wanted assurances, explicit limitations on government power. Many people proposed many such limitations, which James Madison patiently codified into 12 amendments, 10 of which were accepted with the Constitution and became what was known as the Bill of Rights. This was not without debate either. Critics of the Bill of Rights argued that it wasn't necessary to explicitly limit the government because the government could only do the things it was explicitly permitted to do in the main body of the Constitution. That is, if the main body of the Constitution doesn't say the government can establish a religion, then we don't need an amendment saying it *can't* establish a religion. Furthermore, if you jot down explicit things the government can't do, people might infer that, if it wasn't included as a limitation, then the Government is allowed to do it. That is, by including these limitations you might have the opposite affect and empower the government to do things it was never intended to do! In comes the 9th Amendment. It is a bulwark against that implication. Basically it is a reiteration of the basic principle of the Constitution: the government is only allowed to do the things the Constitution says it can. And that just because *some* limitations are noted here, and some *rights* are offered protection doesn't mean other rights not mentioned aren't also protected. There really isn't any specific law that would violate it. Instead, it prevents the government from restricting rights not enumerated merely because they weren't mentioned as being protected."
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784m9n | Why do lights look like they flicker off in the distance even though they aren’t? | Biology | explainlikeimfive | {
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"You know how air looks wavy near the ground during a hot day? That's refraction of light, caused by a difference in air temperature. You are seeing the same thing but at night. The difference in temperature means a difference in optical density. Light bends when travelling between different optical densities, which is pretty much the definition of refraction.",
"Atmosphere. Same reason stars appear to \"twinkle\". That's partly why we started putting telescopes into space."
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784tpp | Why are Benzos the go-to for a lot of mental issues? | I've heard (forgive me if I'm wrong) that for many mental conditions a paramedic, ambulance, or hospital may be called for, benzodiazepines (and benzothiazepine?) are one of the main methods of treatment. Why is this the case? I'd assume given how complex the human brain is that anything which can shut down so many processes at once would be unhealthy. What makes these particular receptors unique to their role in medicating individuals? Thank you for any help and information! | Biology | explainlikeimfive | {
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"They're a tranquilizer. So in any case where there's too much brain activity, or a patient is too agitated, you give them benzo. Quick fix for seizures, panic attacks, anxiety, etc. It's like turning down the volume on the brain.",
"They work quickly and like you said basically shut down the brain for a while. I'm not sure how they do with long term treatment but when you have someone who is agitated and violent, it's safer to go ahead and basically turn them off for a few hours before they hurt themselves or someone else. From there you can formulate a more reasonable treatment plan but the immediate goal is to keep everyone safe. That's why they are used by EMS/hospital staff quite often from what I can tell. Basically a dose of \"calm the hell down for a minute\""
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7854id | how can the same DNA build three completely different forms of a butterfly (larva, pupa, adult)? | they seem like completely different creatures -- different number of legs, wings, organs, diet etc. does their DNA have multiple time-activated blueprints or something? | Biology | explainlikeimfive | {
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"When certain hormones (chemicals) are released, it triggers the production of certain proteins. These proteins float along and literally turn on/off certain genes. These genes are then expressed as a different type of tissue. Tissue becomes organs. Organs become body systems. Body systems create a new creature. So, you are pretty much right in your original thinking. BUT, to explain it to you like you are five...The DNA has all the right parts to let the butterfly grow up and live a happy butterfly life.",
"Short answer: epigenetics Now with that said its basiclly because genes are switched on or off due to their purpose and the enviornment. Its the same reason why our ear has the same DNA as our leg although theyre pretty didferent.",
"About the same way you can describe them with words. First they are a larva, then a pupa, then an adult. DNA is more complicated than language, no reason it can't describe something as intricate as that. And for your second bit yes, that's what puberty is, and menopause, and all the processes you go through as you age. Its not as drastic but its the same idea."
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7856rp | Why does fear increase heart rate? | Biology | explainlikeimfive | {
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"Im sure everyone should know about the flight or fight response. when we see something scary our amygdala releases norepinephrine (adrenaline) or some variation which increases heart rate, and activity in the brain, generally every area of the brain that might save you, say, in the presence of a bear, like the frontal lobe (planning area, motor cortex)"
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7858pb | Why do many juices only need to be refrigerated after opening, but milk needs to be refrigerated at all times? | Biology | explainlikeimfive | {
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"Fruit juices tend to be more heavily pasteurized than milk, which makes them shelf stable. Heavily pasteurizing milk changes the taste and a lot of people prefer the less pasteurized form. Although UHT (Ultra-high temperature pasteurized) milk is commonly available and has a long shelf life.",
"There are some juices that need to be refrigerated at all times, and some milk that needs to be refrigerated only after opening. It depends on how natural or processed it is. UHT milk can be kept at room temperature for months until opened, while fresh squeezed OJ should be refrigerated and may have only a week or two shelf life.",
"It all come down to the pasteurization process. Not all juice needs to be refrigerated and neither do all milks. If the juice is made sterile (all the germs killed) then it won't need to be refrigerated. It is the same with milk. Tldr There are different ways to \"clean\" the juice. If it is super clean you don't need to.",
"It's all down to how it was preserved and what's containing it. Almost all juice and milk is pasteurized. That is, it is heated to kill bacteria and then sealed. However milk usually isn't heated that high and store in a container that wasn't sterilized. If you pasteurized milk at a hot enough temperature and sealed it in a good enough container, you would not need to store it in a refrigerator until you opened it. [You can buy some of that milk.]( URL_0 ) People notice less when fruit juice is heated really high, and all the sugars and no fat make it harder for bacteria to live there anyway. So fruit juice is more often pasturized at the higher temperature. This is not counting stuff like juice from concentrate, which has so much processing everything in it is pretty much already dead."
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785fel | Why insects don't splat in accelerating vehicles | So you're in your car/on a bus/train. A flying insect enters and is flying around when the vehicle goes from stop to accelerating. It doesn't splatter on the back of the vehicle. Can someone explain the physics of this? | Physics | explainlikeimfive | {
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"The same reason you don't go splat if you jump while flying in an airplane, or why helicopters don't go splat because of the earth's rotation - relative momentum. The air in the car is moving the same speed as the car, the bug won't just remain stationary while the car moves around it.",
"> A flying insect enters and is flying around when the vehicle goes from stop to accelerating. It doesn't splatter on the back of the vehicle. The air within the vehicle is carried along with it as it accelerates so that tends to cushion any movement. But also keep in mind that the acceleration forward is significantly less than one gravity so even if the insect was sitting on the back window and subject to the entire force it wouldn't have trouble. *You* would splat before an insect would! The issue is the rapidity of the change in speed. A bug being hit by a 60 mph car changes speed to that of the vehicle in an instant while the accelerating vehicle takes a while."
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785gfc | Why does a glass of wine (or any alcohol) help me write better? | Other | explainlikeimfive | {
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"It's that simple. The only writing advice anyone should subscribe to is \"just write.\" Editing is where most of the real writing happens anyway. For whatever reason, just writing is the most difficult thing for most writers, but it's the quickest path to success in most cases. Alcohol stops you from thinking too hard, relaxes you, and you just write."
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785he4 | Why people who have $70K Plus in savings would get a secured loan for a $35K car. | Economics | explainlikeimfive | {
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"Liquid assets are a good way to reduce risk. A car loan can be had at 3%, it may be worthwhile to take the 3% hit in order to have more liquid cash The next though, and generally better reason is that the $75k is primarily in investments, not sitting in a bank account doing nothing. Its fairly normal to assume you can make an 8% gain in a low risk mutual fund investment, which means that you actually make more money by financing at 3% instead of taking away your money that is making 8%. To take it further, this is how a lot of businesses operate! You take out a loan at say 10%, but if you can make 80% return on it by investing in your business, then of course you're gonna take out a loan right?!"
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785jfy | Are birds technically reptiles? | Biology | explainlikeimfive | {
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"**Birds are most closely related to crocodiles. ... So birds aren't just closely related to dinosaurs, they really are dinosaurs! This is what most people mean when they say that birds are reptiles, although technically according to the phylogenetic system mammals are also reptiles.**",
"Some experts consider birds to be part of reptiles, yes. Sometimes the phrase *non-avian reptiles* is used to include what we laypersons would call reptiles while excluding birds. classes are not the be-all end-all; As we learn more about how closely an animal is related to a different animal we often find things that don't fit an earlier interpretation of their relationship. We have now determined that what was usually considered to be the class *Reptilia* is not a monophyletic group and the real relationship is much more complex.. until we learn more and have to change the groups again!"
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785m24 | The Genetics of Haemophilia A. | Why do people get Haemophilia A? What happens at the genetic level that makes suffers bleed so much? | Biology | explainlikeimfive | {
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"When you get a cut, it blood can leave at the site of the injury. If this kept happening, it would be bad, because you'd lose a lot of blood. The body has ways to stop this from happening, and we call this clotting. It's the body's way to sort of make the blood less like a liquid and more like a gel, stopping it from running out. One way the body does this is through the coagulation (or clotting) cascade. When there's a cut, the cells around the cut release a messenger that basically says \"Ahhh there's a cut!\" This messenger starts the cascade, which is kind of like a pyramid scheme recruiter. It tells 10 of its friends, who each tell 10 friends, who each tell 10 friends, etc. So in a little bit, you have 1,000,000 friends all helping to plug up the injury. Hemophilia A is a problem with one of the \"friends\" that helps to make the stuff to plug up the injury. This friend, (called Factor VIII) is important, because remember this factor recruits other factors to help too, so if it's not there, we miss out on a lot of help to form the clot. Our genes have DNA, which is the blueprint that tells cells what to build and make - proteins. One of those proteins is Factor VIII. In people with hemophilia A, they have a problem making Factor VIII. Some people have a Factor VIII that doesn't work right, and others just don't make enough of it. Either way, someone with hemophilia A is going to take a lot longer to clot appropriately. The gene that tells the body to make Factor VIII is located on the X chromosome. Genetic males typically have one X and one Y chromosome, and genetic females typically have two X chromosomes. For genetic females, if they have one X that is normal and one X that carries the hemophilia A gene, their good X chromosome can make enough Factor VIII that they're fine. But for genetic males, the Y chromosome doesn't have anything for Factor VIII, so their single X chromosome makes a faulty Factor VIII (or not enough Factor VIII), leading to hemophilia A. This is why hemophilia A is much more common in males than females - genetic females would need both X chromosomes to have the affected gene. A treatment for people with hemophilia A is to inject them with the clotting factor that they lack, in this case, Factor VIII. Other types of hemophilia are missing other factors - type B is missing Factor IX and type C is missing Factor XI. Let me know if you have any questions! Happy to explain anything at a more advanced or more basic level :o)"
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785olk | How do fingernails grow? | What are they made of? And why do they grow basically indefinitely? How do they stay firmly in place in fingers/toes? Are they attached to bone or something? | Biology | explainlikeimfive | {
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"Nails are made of a protein called *keratin*. They're relatively strong and what's most important, have properties that allows them to stack and accumulate to give them hardness - much like we'd weave spider silk together. Keratin is found in in hooves and horns of animals, as well the skin and hair. They do have a specialized location from which they grow, underneath the skin and near the bone. It's not so much that they're \"firmly attached\" to a specific location, but rather embedded in the skin itself: much like hair - nails are capable of being seperated through force, but due to their shear size and location a lot harder. Just like hair, hooves and horns, they grow because keratin is essentially a \"dead\" material. Nails do not contain blood vessels and have no connection to the inner workings of our body. The body can't repair them, we can simply only add more of it. They're made of this dead material and repair itself by growing because they wouldn't be able to function otherwise: it's rigidity is very useful for clawing or pinching things."
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785viq | What is the basal ganglia? Location? Function? | Biology | explainlikeimfive | {
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"Basal ganglia are a bunch of smaller brain structures beneath the cerebral cortex, and above the midbrain structures like the thalamus. They are involved with choosing actions to perform, and work partly by suppressing actions you shouldn't perform."
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786021 | If private investigators can't break the law, what abilities does a PI License get you that a normal person wouldn't have? | Other | explainlikeimfive | {
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"To a degree, it gives you a presumption by the police that you are not intending to commit a crime. It's not a \"get out of jail free\" card, or even a \"we're not going to harass you\" card. But it gives you a somewhat valid reason to be loitering or following someone or taking pictures, activities which although generally not illegal per se can be viewed with suspicion by the police.",
"It depends on the jurisdiction. Most commonly, it gains you the ability to accept money for performing investigations, and to advertise that ability, which would otherwise be illegal. In some places, it may also allow you to carry a firearm or do other related activities that wouldn't be allowed by members of the general public."
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78659t | How do defense attorneys deal with clients that they know are guilty of the crimes the client is charged with? | Other | explainlikeimfive | {
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"They defend them at the best of their ability. That's what they do, they try to give the best outcome in their own professional opinion to the one their representing. That can be that they advice the client to confess or it can be to advise them to keep their mouths shut.",
"> What are the lawyers options? They can follow their oath and defend their client to the best of their ability, or they can refuse to represent them and forfeit payment. The latter may also put their license to practice law in jeopardy depending on the circumstances. Even people who commit crimes deserve their right to a legal defense. Respect for this basic right is expected of lawyers.",
"The ethics issue others have already pointed out is there in no small part because nobody wants the local lawyer community deciding who is guilty. If situations came up where all the local lawyers could readily just say \"nah, not representing this guy cos I think he's guilty\" a lot of possibly innocent people would have an even harder time getting a fair trial. Guilt is for the Jury to decide (or Judge in a bench trial). Additionally, even if someone is guilty, and maybe *EVERYONE* knows it, and the fact they did it isn't really in question - the defendant may want a trial to try plead their side of the case, either to provide mitigating circumstances to try for a reduced sentence, or because they believe they have been over-charged by the prosecutor. And also, most countries dont have a \"Justice System\" they have a \"Legal System\", with heavy emphasis on the \"System\" part. In any dealings with the courts the processes are vitally important, where everything has to be followed to the letter and deadlines must be met. Failure to file a document, or messing up navagating this system, even when planning to plead guilty with no contest to the charges can result in serious long term implications that can be difficult, if not impossible, to remedy later on. At the absolute barest minimum everyone deserves representation to advise them and guide them through this so they don't accidently screw themselves over 10x harder than they needed to.",
"The state has an obligation to prove guilt. By making it hard to convict a guilty person, a lawyer helps protect all of us by helping ensure it's even harder to convict an innocent person.",
"They look for sloppy police work and holes in the evidence and use that to demonstrate that the proof is incomplete. They don't have to prove innocence, just make it harder to prove guilt. This is why we should blame cops for doing sloppy work and not anyone else. They are protecting all of our rights by holding cops to higher standards.",
"Even a guilty client has the right to a fair trial and a fair judgement of the crime to make sure the punishment is proportional to the crime. And, morals aside, unless convincing enough evidence is presented, you can still try to get your client off the hook.",
"I worked on the computers of a local lawyer that represented a truly horrific couple that starved their two children that they locked up in a closet for weeks at a time. There was no presumed innocence, they fully admitted to it. I asked him why in the world he'd represent such disgusting horrible people instead of attacking them on the taint with a rusty saw blade and watch them bleed to death.. Basically he said that (1) he had been appointed to represent them by the presiding judge so he couldn't exact pass (he said he could use his law license) and (2) his only real job was to ensure that they were treated \"fairly\" in the eyes of the law (they couldn't get executed when the max was, say, life in prison). Hey said that, in the beginning of his career, he hated representing people like that but soon came to realize that *someone* had to for us to remain a land of laws. He certainly didn't represent people like that for the money since they had none so he had to take their old run down cars as payment. (Someone else got the house)."
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786aus | Why does every bottled ranch taste the same and none of them taste like restaurant ranch? | Other | explainlikeimfive | {
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"Ph changes because of storage requirements and FDA approved nonsense. In small terms the restaurant ranch is fresh and the store kinda has lost its freshness due to the preservatives added. I was the cook who made all the ranch at 3am. It sucked but it was Soo good with French fries and sea salt."
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786d7a | Why do you sometimes hear very faint music when taking a shower? | Other | explainlikeimfive | {
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"text": [
"The water and pipes make all kinds of random sounds. Your brain struggles to find patterns in the complex noise, eventually making up patterns that aren't even there.",
"There is a piano playing behind a few walls. Or you are simply imagining it. Or it's simply a rhythm caused by the flow of water in your pipes. Or it's a different sound from further away that you're able to hear when you stay quiet."
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7871y5 | How do modern military generals use ancient military tactics/strategy's? | I hear this every so often when I watch historical documentaries, for example they go on about a certain tactic or strategy that Alexander the Great used in a battle and then they say that a modern general used the same tactic in a modern battle, but how can that be possible with all the changes to military hardware, the use of tanks and other things? Just wanting to know how it can be transferable aside from just taking basic movement tactics or something else from basic. | Other | explainlikeimfive | {
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"On the level of military *hardware*, you're right. A lot has changed in the last few thousand years. But the *goals* of military conflict are basically unchanged: do enough damage to the other guy that he can no longer prevent you from carrying out your operational objectives while keeping one's own casualties to an acceptable minimum. With that in mind, certain patterns emerge, patterns that can be applied *across* history, even if the specific way they are *implemented* has changed rather drastically over time. Examples, many of which overlap: * If at all possible, fight at a place of your choosing, not a place of your enemy's choosing. * Don't attack a fortified position if there's any way of avoiding it. * The mobile force has the operational advantage over the force that is fixed in place. * Attack when your enemy least expects it, not when he would prefer it. * Attack from the direction your enemy least expects it (one of the things mobility lets you do), not from the direction he has anticipated. * Attack where your enemy is weakest, not where he is strongest. * Attack in ways your enemy is least prepared to defend against, not in ways he has anticipated. * It doesn't matter how many more troops one side has if he can't bring them all to bear at the same place and same time. So yes, *particular* tactics, e.g., the massed heavy cavalry charge, the spear-armed phalanx, the massed infantry charge, broadside-style naval tactics, have certainly gone by the board as military hardware has evolved. And even where *categories* of tactic/formation have survived, the *specifics* will change with hardware (e.g., there's a reason tank units are called \"armored cavalry\"; many of the principles are the same, even if range is measured in tank fuel instead of horse feed, etc.). But a commander focused on pulling off specific tactics obviously suggested by his hardware has, in the long run, already lost. The successful commander will remain focused on *accomplishing his objectives*, and will seek to use whatever hardware is at his disposal in bringing that off as efficiently as possible, guided by principles like those listed above.",
"You are right, it is very hard/impossible to win a modern battle using *solely* ancient tactics. Often what narrators and commentators mean is that a particular basic maneuver was first demonstrated successfully or was famously executed by a particular military leader. Due to this, it was widely studied and promulgated in war colleges and the like. As a result, it is now a classic maneuver or building block used as part of a larger military strategy or operational plan."
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787g51 | Why do deer antlers all look different? How do they grow? What purpose do they have? | Biology | explainlikeimfive | {
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"They grow like normal bone, and are covered by \"velvet\" until they rub it off to expose the bone. They grow and fall off every year in male deer. There's a lot of genetics and environmental factors behind how they look. Healthy adult deer will have bigger and stronger antlers. And they are used for clashes between males competing to mate with females. They can also be used as a method of protection against predators."
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787o2w | Why does the moon turn reddish/orange sometimes during a full moon? | Physics | explainlikeimfive | {
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"Same reason the sun turns reddish/orange at sunset and sunrise: because the Earth's atmosphere scatters blue light in all directions, letting the red and orange come through. To answer the question behind your question, why does the full moon look reddish when the crescent moon doesn't? It's just a matter of when you choose to look. The moon will always look reddish when it's near the horizon, but the full moon is near the horizon right after sunset, when people are most likely to look at the sky. The waxing and waning crescent moons rise and set either during the daytime (when they're hard to notice) or late at night when you're asleep."
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787sh5 | Why do we get dark circles/bags under our eyes when sleep deprived? | Biology | explainlikeimfive | {
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"The skin beneath your eyes is thinner than skin elsewhere on your body. Underneath that skin is blood vessels. When you get tired your body releases cortisol to help keep you awake. Cortisol makes your vessels larger and more apparent hence the darker circles. If you lay down for a long period of time you'll have more blood rushing to your face. This is why when you wake up you have a similar bags."
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787smb | What is Cinematic Urbanism? | Other | explainlikeimfive | {
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"Particular cities show up repeatedly in movies: New York, Paris, London; even when filmed in other cities like Toronto. The result is a sense of familiarity when watching a movie, as though one has been to a place, even though only through a movie screen. While some natural locations have been used over and over, they don't have quite the same emotional tug as Central Park in the fall, or the Eiffel tower at night, sunset over St. Paul's, or the neon lights of the Ginza or Las Vegas... To the point where we get a cultural understanding of \"City\", or the urban landscape, that is defined by our cinematic experience, and not reality."
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787vid | What is the difference between all those different types of toothpaste? | Other | explainlikeimfive | {
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"There's not a lot of difference. Some manufacturers will add materials that have certain properties, but in real-life use, those properties will be minimal. Examples: Whitening toothpaste contains a higher level of ~~surfactants~~ abrasives, essentially \"scrubbing\" the surface of the tooth clean. This can damage enamel over time. They may also contain bleaching agents. \"Enamel repair\" toothpaste contains calcium-based substances that are reputed to replace the surface layer of enamel. They are essentially a stopgap, and the material that's deposited will be removed pretty swiftly. We cannot replace enamel manually, and the body doesn't produce any more over time. Cavity protection will be through addition of sodium fluoride, which is proven to help with strengthening of the enamel. So that actually does work, but the vast majority of toothpastes have sodium fluoride in them anyway, so claiming \"cavity protection\" is redundant. Put simply, just buy a cheap, fluoride-containing toothpaste, and use it. The physical action of brushing is far, far more important than the type of paste you use. . *edit* **Holy crap**, inbox asplode. Thank you for gold, kind mystery redditor. All of the above still applies, but I thought it might be useful to add in some information that others have stated below, or that I left out. So, first off, things that *do* affect dental hygiene and effectiveness. First and foremost, since it's the single most important thing - brushing technique. The vast majority of people don't have great brushing technique with manual toothbrushes, so it's commonly recommended that everyone uses electric toothbrushes, which do the \"hard bit\" for you and provide the most comprehensive brushing possible. This technology is gradually evolving over time, but the rule of thumb is to go for one that has three key movements - rotation, in-out vibration, and oscillation. These three things have been proven to effectively clean the tooth surface, and stimulate the gum line, resulting in improved overall oral health. /u/tcmaresh and /u/unsanitary_napkin made an excellent point - toothpastes that say \"9 out of 10 dentists recommend\" only say that because dentists recommend that people use toothpaste. That's it. They're not recommending a brand, they're recommending toothpaste in general. Additionally, in order to be approved by the dental association, they have to work, and not do any harm. Those are the only two requirements. Next - flossing, and interdental brushes. The general consensus is that brushing *and* flossing is better than either one or the other, but there is a growing body of research that suggests flossing is not as effective as interdental brushes (again, when used in combination with normal brushing). Do some reading up on ID brushes, and give them a try if you want to. But if you're flossing regularly (or not) and your dentist has told you your teeth are in good shape, just stick with what you know. Now, on to other toothpaste ingredients. As some have stated, brushing *without* toothpaste actually removes just as much bacteria, food particles and tartar from the surface of the tooth as brushing *with* toothpaste. However there are some ingredients that prolong the effectiveness of brushing, give fresher breath, assist with gum health, etc etc. So, some examples below. \"Sensitive\" toothpastes. This includes Sensodyne. There are some ingredients, particularly Novamin, which do appear to significantly help with tooth sensitivity. These do not aid with overall oral health, but they *do* help with your teeth not feeling like they're being ripped in twain on a daily basis. Worth using if you suffer from this affliction. Fluorides. Whilst sodium fluoride is the \"standard\" substance for fluoride delivery to the enamel, as various people have stated, there are others. These include stannous fluoride, one that's still used in certain brands. All of them have the same mode of action, which is to deliver fluoride to the surface of the tooth. Some make it more \"available\" than others, but the difference appears to be fairly minimal. Stannous fluoride can give some people problems, including tissue sloughing (bits of skin coming off the inside of your mouth), gum whitening, and tooth staining. Ultimately though it doesn't really matter what type you use, as long as you use it. Note that all OTC main brand toothpastes will typically contain the same amount of fluoride. Prescription toothpastes are different, and contain more. Antiseptic agents - this includes Chlorhexidine and Triclosan. These remove bacteria from the mouth, and can assist with gum health and cavity prevention; they also hang around in the area, preventing bacteria from returning. Antiseptic agents can be beneficial, but some studies have suggested that we need to maintain the \"good\" bacteria in our mouths, which assist with prevention of halitosis and tartar buildup. So approach with caution, but they are generally good to use (this includes mouthwash). Enamel repair. This has come up a lot. There are some substances which appear to promote remineralisation of enamel. However, having done some reading up of my own, this effect is minimal, and occurs over a long, long period of time. It may still be beneficial for some, but consuming acidic foods or drink will quickly reverse the process, so diet control is needed alongside use of these substances. As per my original response, just brush your teeth. If you want to include enamel repair toothpaste (at a significant price), feel free. But it's not essential. Xylitol. This is a sugar substitute that is included in a lot of chewing gum, and some toothpastes. Its key benefit is that it cannot be digested by bacteria, so it offers an excellent sweetening alternative. Some studies have shown that xylitol can remineralise enamel; but these studies have been done using 20% xylitol solutions at 37^o C, over two weeks (with constant application), which isn't really relative to the real world. But yes, it has its benefits. It's in a decent number of toothpastes already, so feel free to use if you want. Foaming agents. The most common foaming agent in toothpaste is Sodium Laureth/Lauryl Sulphate, the same stuff that is used to make liquid soap foam up. It's an irritant, and can cause problems in people with sensitivity to it, including ulcers (canker sores), lesions and general irritation. If you are susceptible, find a toothpaste that doesn't contain it. The amount of foam a toothpaste produces does not relate to its cleaning ability. Baking soda! This stuff is present in Arm and Hammer and some off-brand products - it's basically an abrasive, and aids with whitening of teeth. The same caution applies as with all other whitening agents - it damages enamel. So approach with caution. Baking soda also neutralises acid in the mouth, but that effect will be negated as soon as you consume anything acidic. So very much a temporary solution. /u/FranDankly very kindly [provided a link]( URL_0 ) which covers the abrasiveness of various well known brands - it may prove useful for some. Note that abrasion is still beneficial in most cases, but excessive abrasion ain't good. Worth noting that most whitening toothpastes are on the higher end of the scale! I think that's about it for now... but regardless of all the added info above, the action of brushing is *still* far more important than anything else (whether or not you combine with flossing). Brush dem teefs!",
"My daughter JUST did a report on toothpaste for school so this info is fresh in my head. :-) **TL;DR:** Generally speaking there are no differences that make any one toothpaste better than any other toothpaste *at the job of being toothpaste*. All of them (or, funnily enough, none of them) will get your teeth equally clean, and any ancillary benefits that a toothpaste may claim have no effect on their ability to be toothpaste. Full explanation: Toothpaste is considered a **parity product**. A parity product is any product that's functionally equivalent to any other competing product that may be offered by a competitor. Products like nails, peanut butter, gasoline, and soap are parity products because they are all functionally identical to products offered by competing companies. Any differences in parity products are largely superficial, perceived, or add no *measurable* or *functional* benefit to the product. For example, some oil companies will tout how their pumps are equipped with special filters to make sure the gasoline coming out is more pure, or how they've got special additives to help engines run cleaner and more efficiently. The veracity of these claims are supported by the use of wiggle words like \"more\" or \"help\", but fundamentally the gasoline from any given oil company is 100% identical to gasoline from any other oil company. Any difference in price between two competing gas stations has to do mainly with the effectiveness of their advertising. Lots of people would consider paying a bit more for gasoline from Dinoco than they would from MomsNPopsGas if they *thought* that Dinoco gas was better. In specific regards to toothpaste, there are generally four ingredients in virtually all toothpastes: water, abrasives, sulfactants, and fluoride. Individual products are differentiated by colors, flavors, task-specific additives that aren't strictly necessary for the task of *toothpaste* (e.g., hydrogen peroxide as a whitening agent, or potassium nitrate as a desensitizer), and of course packaging (striped toothpastes are popular). It's these non-purposed variations that give rise to the ten thousand different tubes of toothpaste in your supermarket. Fun Fact: In the world of parity products, any competing product can legally call itself \"the best\" in its genre for the purposed task. Toothpaste's job is to help keep teeth clean (Another Fun Fact: brushing with or without toothpaste has no bearing on the amount of plaque removed from teeth) so if they all have the same *functional* ingredients then there can't be any one product that's better than any other; ergo, all products are \"the best\" at being toothpaste.",
"I guess it's not very popular outside of scandinavia but here in Finland many toothpastes also contain xylitol on top of fluoride and these both have similar effect. Asian tourists seems to be stocking up on this stuff since you can't get it in most places. Most chewing gums here also contain xylitol.",
"Dad is a dentist... Toothpaste basically all the same ( unless you have sensitive teeth, then yes sensodine makes a difference). He said buy the flavor you like, he always got AIM or close up, which ever was cheaper. For him the type of toothbrush you use is more important. He is a big electric toothbrush advocate. He has used both oral B and so I are, he was usually trying out the newest model. Flossing is also huge!",
"So all the top level answers are awesome and perfect but I do want to add an explanation about monofluorophosphate, sodium fluoride, and stannous fluoride. The three substances listed are all fluoride ions but they are different. Stannous fluoride in particular is famous for its odd BUT benign side effect of staining the gums white temporarily. In some clinical studies, stannous fluoride was show to be slightly more effective than monofluorophosphate or sodium fluoride. However, the difference is largely negligible. Basically as others have pointed out, as long as fluoride is present, toothpastes are more or less the same. Sulfate ingredients will make toothpaste extra foamy and baking soda or hydrogen peroxide will aid in removing surface stains. And of course sensodyne is perfect for those with sensitivity issues. Tl;dr there are slight negligible differences between stannous fluoride, monofluorophosphate, and sodium fluoride.",
"My dentist told me bog standard Colgate is the best, and definitely not to use whitening toothpaste. In that vein she said that OralB ProExpert is way too abrasive and had caused a number of ‘wear’ fillings in her patients. Forget the technical term...",
"Life Pro Tip when it comes to toothpaste. The ADA seal is only applied if the ADA determines a toothpaste is \"Safe and Effective\". That means the have tested it and it (a) won't harm you when used as directed, and (b) it does what it says it does. That's it. No other requirements. Most of the toothpastes on the shelf have NOT earned that seal. Not because they are safe, but usually they because they don't live up to the claims (e.g. whiten teeth). Don't buy a toothpaste without that seal of approval. Because, without it, how do you know it's safe? It probably is, and the toothpaste probably failed to earn it because of the other claims, but do you want to reward the company for lying?",
"My dental tech told me to buy the cheapest tube that said anti-tartar on it. I have extra special hard buildup and need the cheap sand (diatomaceous earth) to get it off. Everything else is just marketing, though the toothpastes like Sensodine do help some people, depending on the reason your teeth are sensitive.",
"One of the biggest differences in toothpaste is the presence of Sodium Lauryl Sulfate (SLS). SLS is used to make toothpaste super foamy, but it can dry out your mouth, make the insides of your mouth hurt, and possibly even make your allergies worse! I used to get really bad canker sores on my gums but I switched to a toothpaste without SLS and it totally worked! I prefer the Sensodyne Pronamel toothpaste myself. a source: [Most toothpastes contain Sodium Lauryl Sulfate which is a chemical used in toothpaste to create the foaming action. SLS can cause or irritate existing allergies, canker sores and bad breath, which is why an SLS Free alternative is worth considering.]( URL_0 ) a second source: [The ingredients in your toothpaste are as important as the ingredients in your food, but -- like many cosmetic products -- toothpastes contain chemicals that would never appear on your dinner table. One example is sodium laurel sulfate, present in over 100 dental care products rated by the Environmental Working Group, a consumer health organization. Finding a toothpaste without SLS can be accomplished by learning a few brand names or by making your own toothpaste at home.] ( URL_1 ) More on SLS itself: URL_2",
"I was taught 30 years ago to only go with toothpastes that carry the [American Dental Association seal of acceptance]( URL_0 ). There are fewer and fewer toothpastes these days that have earned it. You'll notice that almost none of the \"whitening\" toothpastes carry it. Ironically, Aim, one of the cheapest brands, does. So that's what I buy. (I'll wait now for someone to tell me why this doesn't matter at all.)",
"I'm no expert but i took exceptional care of my teeth and was still managing to get cavities. Doc gave me a perscription level toothpaste with 150x the fluoride and now i have no problems",
"So reading through the comments there appears to be no significant difference in toothpastes, so I was wondering if there's also no differences between mouth washes?",
"The differences in major brands are mostly flavoring or cosmetic. However specialty toothpastes like sensodyne have an extra ingredient that helps reduce sensitivity. There are also different mixes of whitening ingredients as well.",
"This is a very minor, not-very-relevant difference, but I know that most \"sensitive\" toothpastes lack the chemical sodium laural sulfate. I don't know *why* they don't have it, but I do know that it's a foaming agent and that causes super annoying acne in some individuals. So, useful to know that difference if you're in the small group of people with stupidly sensitive skin.",
"Toothpaste industry is an oligopoly market. The main characteristics of such a market is that there are limited number of players and they do not go in a price war - otherwise all of them would be dead in a days time. What they instead do is to bring out new and innovative ways to sell their toothpaste - this includes that, ours is better, try this, etc etc.. Most of 5his innovation is artificial.. does not help anyone using it.",
"The chemical makeup differences are minimal. The advertisement, packaging and implied or stated effects (that exist in other pastes) are what is used to say X is better than A,B,C,D just ask out 9 out of 10 dentists. Colgate blasted radio and TV in the 20's up till today. Colgate, through sales and adverts, put Gleem, Stripe, Ultra Bright, and Pearl Drops in the ground. the differences between Colgate and other brands, as with theirs to Colgate, is usually an increase or decrease of specific chemicals. Some taste better, others scour the mouth free of germs. The worst idea, though, has to be antibacterial toothpaste...",
"One answer covered the practical aspect of it. I'll deal with the Economics of it. The reason why there are so many toothpaste is that people like different things! Some like blue boxes, other are concerned about how white their teeth are and other like their toothpaste to be striped like the one they saw used by that beautiful man on TV! So now imagine you are a toothpaste company making one white toothpaste. If you started making two toothpaste, a white and a striped one, you'll be attracting (a little) more customers and make more money! But of course you could do this again, you could offer a simple box version of each and foiled version. So basically, a company will expand his variety as long as it can profit from it! All markets where the basic content of the product is fairly cheap to make will see a lot of \"varieties\" being sold (think breakfast cereals, toothpaste, detergents). There is also one more important reason why expanding varieties is good for companies : if you are selling many different types of the same item you are effectively creating a market for each one (one for all the consumers who like stripey ones, one for those who like foil boxes etc..). Each market might be tiny, but they add up to a lot. This in turn makes it harder to compete against your company. If you are a new company you will have to come on the market with many varieties matching the older firms. If you just competed for stripey toothpaste you'd get very few customers, because you'd be splitting customers who like stripey tooth paste who are just a small subset. To understand why this is the case think of the fact that if instead the older company was selling only one variety most customer would be buying that(since they don't have an alternative) . In turn, a new firm entering by making one product could potentially get half your business! Industrial economics, over and out!"
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788bda | How did "cheater boxes" (cable descramblers) allow you to watch premium TV channels for free? | I had a few friends who had one back in the 90's that allowed you to get HBO and pay-per-view without actually paying for it. I always wondered how they work. | Technology | explainlikeimfive | {
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"Way back when, television was an analog signal. More accurately, it was a *series* of analog signals that your 100%-analog color television could use to produce a picture. You have three signals for color (your TV only looked at one if it was black-and-white) and a \"timing\" signal that indicated when it should start drawing a new line. The \"vertical hold\" was a sometimes-manual synchronization to that signal. \"Scrambling\" was really just that. Some of the signals were inverted, some of them were switched. But, fundamentally, you couldn't *add* in junk or actually do significant *math* to obscure the signal, because televisions simply didn't have the ability to un-do that and produce a working picture for your paying consumer. Likewise, before relatively powerful integrated electronics became available, it wasn't economically feasible to give a customer a powerful computerized set-top box just to watch some television. So your \"encryption\" was a scheme with only a few variables. Throw off the synchronization here, swap a color field here, and it would make the picture \"off\" enough to be unwatchable. But, likewise, once someone figured out your mechanism, they just had to create a relatively simply \"decoder\" to bring that signal back. TLDR: Analog encryption wasn't terribly complicated, but it was analog, so it required *hardware* as opposed to something digital, which might be more complex, but also could be done with a wider variety of hardware. Nowadays, everything is digital (because computing power, even for high-definition video, is so cheap) so analog encryption/decryption isn't a thing.",
"I built a couple of those for friends and family. The vertical sync signal was missing, so this box would create its own. You then had to fine-tune it manually to get a stable picture on your TV. Later, with the DirecTV systems, people hacked the plug-in cards that came with the box. The programming hardware was technically illegal in the US, but was about $80USD from a Canadian company. A friend was part of a \"dark web\" hacker group, and every time DirecTV changed the codes, they would be hacked within hours. Reprogram your card and you had everything. One thing you had to remember was that your box couldn't be connected to the telephone line, else DirecTV could \"call\" your box to see what it was doing. That's how they did remote fixes and upgrades back then. DirecTV finally came out with a new box and card system that couldn't be reprogrammed with the previous gear, so that was the end of that.",
"Everyone is talking about \"way back when\" and \"did\" but I have a cheater box rn? I have all of bell broadcasting for free...",
"For the digital age, things work somewhat differently. The encryption itself usually isn't broken but some other part of the hardware might have a flaw that lets you access the key data, be it a season interface, an firmware dump or just insecure key distribution. Once you get ahold of a valid key, you can rather easily emulate most common cryptography systems (in the end it's just some protocol plus AES) either in hardware or nowadays more commonly in software. Nagravision2 had such a major flaw that any key change would lock out pirate decryption for a few hours tops. Most paytv networks will weigh the suspected amount of pirate decryption against the tremendous costs of implementing a newer encryption system (usually that requires at least a smartcard change, tough luck if they went cardless and now have to exchange all the boxes). As long as the illegal decryption process is complex enough to deterr the average teenager, requires expensive hardware or at least some sort of fancy setup, they'll let people get away with it. More recently, cardsharing has been the typical way to go. Essentially, there's one valid and paid subscription in a cardreader connected to some sort of server (cable boxes, RasPis, full blown x86 servers, even internet routers like ddWRT boxes have been successfully used) and they handle the requests from the clients that connect via internet. Depending on the card in question, a dozen individual viewers is fairly easy to handle, using two or three cards can even result in as many viewers as your internet connection can handle (and that's a lot since only a few kbytes are sent and received every couple seconds). Recently though, providers have been switching to systems that pair the card with a particular box or have gone cardless alltogether - really annoying for people who simply want to use better hardware than the usually crappy provider boxes and do nothing illegal otherwise.",
"On the scrabmblers in the town I used to live in. Pin 4 of the chip would be 0 Volts on unsxrambled channel and 5 Volts on scrambled channels. So pulling the chip from the socket and bending pin 4 straight would let you watch anything you wanted.",
"Rockwell Collins in Cedar Rapids Iowa had a big controversy wenden management discovered a clandestine line in the plant where cheater boxes were being made. An actual line, with people assigned to it, making professional cheater boxes by the 10s of thousands. Selling them in the 80s fit like 30-40 dollars.",
"Boxes had EPROM chips. Cable companies sent EVERY SUBSCRIBER every channel that was available. Open box, dremel cut the epoxy chip that came with the box. Install $0.89 chip that you could buy hundreds of....",
"The best were the K band satellite hacks. Modded boxes for the 8’ dishes that enabled thousands of channels on dozens of satellites. It was like the selection available on the internet in the 1990s. Hundreds of channels of anything. The most fun we’re the news feeds - the remote camera feeds from the news stations. Watching the “Off broadcast” shenanigans of the feild reporter were fantastic."
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788ngr | How do simple electric motors work? | In my physics class we made a simple electric motor using a battery, coil of copper wire, and a magnet. My teacher then went on to explain how the current (I), the magnetic field (B), and the force (F?) cause that little loop of wire to spin continuously. I learned abour it all in highschool, and I remember it made perfect sense, but when I'm relearning it now it is so confusing. No matter how much I ask the professor or GSI, I simply can not understand what force is, how it gets a direction, and how it interacts with current and magnetic field to create movement. | Physics | explainlikeimfive | {
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"You have a rotor (rotating magnet) and a stator (static magnet; for example fixed to the case) in an electric motor. One of them is a permanent magnet, the other an electric one. If you switch on the electric one, it makes north and south poles, which leads to the permanent magnet(s) aligning itself. So the south pole of the electromagnet goes to the north pole of the permanent one. Now, it would be a relatively boring thing if that was that, as you'd only get a short movement once and that would be it. So the polarity of the electric current is reversed, meaning that its north and south poles switch and now you suddenly have north to north and south to south. The magnets repel each other while the opposite poles attract, that means you get another bit of turn. This game repeates, the electromagnet constantly switches polarity, which leads to a constant attraction and repulsion of the static poles. There's more complex setups, especially with more than one pair of electric and permanent magnet, but fundamentally that was that."
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788sbc | How did Switzerland maintain its neutrality during both world wars? | Other | explainlikeimfive | {
"a_id": [
"dorwc30"
],
"text": [
"The Treaty of Paris in 1815 established that Switzerland was to remain a neutral country, and all of the major European powers agreed to it: > On 20 March 1815, at the Congress of Vienna, the European powers (Austria, France, Great Britain, Portugal, Prussia, Russia, Spain and Sweden) agreed to recognise permanently an independent, neutral Switzerland, and on 27 May Switzerland acceded to this declaration. More generally it is believed that because of its position and mountainous topography, Switzerland would be more trouble to invade and occupy than it is worth, and it does not control any mountain passes that can't be circumvented elsewhere. So it is kind of like a porcupine, easiest to just go around it."
],
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19
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|
78949z | How does a Thermoelectric Generator work? | Technology | explainlikeimfive | {
"a_id": [
"dosd73s"
],
"text": [
"What is really being asked is how the thermoelectric effect works, so I'll try and explain that. Imagine you had a metal wire that has either end held at a different temperature. The electrons in the metal act similar to a gas, where the electrons at the hotter end are moving faster and spreading out more. This causes a higher concentration of electrons at the cold end, which causes a voltage difference between the two ends of the wire. Note that different materials will generate different voltages, even under identical thermal conditions. A thermocouple or thermoelectric generator uses two dissimilar materials, with the hot ends attached together. This guarantees that there is a voltage difference between the two cold ends, which can either be used in power production or as a measurement signal."
],
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3
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|
789fsx | Is the stopping power of a firearm purely determined by the amount of energy it outputs? | Physics | explainlikeimfive | {
"a_id": [
"dos3s18",
"dos31yj"
],
"text": [
"Not at all. The stopping power of an ammunition is not really quantifiable, because there is just too many variables. - The trajectory of the bullet. Does it hit a vital organ, sever an important artery, etc. - How the energy of the bullet is transferred to the body. Does it stop quickly and cause localise damage, does it go through the target and only transfer a portion of it's energy, does it fragment or transfer energy over a large volume to cause large damage, etc. - The mental state of the target. Someone could go down in pain from a bullet in the arm, while another could continue to fight you with 6 bullets in the chest. Adrenaline or drugs can completely change the situation.",
"The projectile (bullet) also plays into the factor of \"stopping power\". Depending on the shape and jacket material of the bullet, it can be designed to cleanly go through a target, tumble upon impact, or mushroom (flatten). Given the same amount of powder, projectile weight and caliber, the one that mushrooms will have the quickest transfer of energy into the target. The one that tumbles is likely to do the most damage to the target over a larger area, while the one that cleanly passes through the target will have the least stopping power. Most ammunition used by militaries are designed not for the most destruction, but to disable a soldier from continuing to fight, which means the bullets are not designed to mushroom and have a stronger casing. Transfer of energy into the target is the determining factor of \"stopping power\"."
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789jse | How does a toxicology test work? | When a person's blood is tested for drugs, how does the lab determine which drugs are present? | Chemistry | explainlikeimfive | {
"a_id": [
"dos2y52"
],
"text": [
"Using analytic equipment. There are machines called Mass Spectrometers that take a sample, and can display the mass, and rough percentage of how much of the sample is comprised of the given compound. So if I run a blood sample through a typical gas chromatography mass Spectrometer (or GCMS for short) for a drug test or something, all I have to do is look through the printout to find stuff with the same mass as common drugs (or their metabolites) to determine whether or not you ingested drugs. Mass spec doesn't give names or anything on an analysis, you need to know the mass of what you're looking for to pick it out of the list, and even then, there's lots of funny reasons you will see head scratching data."
],
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3
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789m81 | George Soros | Other | explainlikeimfive | {
"a_id": [
"dos3b3m",
"dos86b6"
],
"text": [
"He a billionaire who donates money to causes he supports, but because he’s liberal and Jewish, the right wing tap into the old tropes of anti-Semitism, especially the lies surrounding Jewish bankers/financiers.",
"He's the liberal version of the Kochs. Literally: They both founded Washington think tanks, they both support politicians that share their views, they both fund academic organizations, etc. So, they both attract the conspiracy theorists from the opposite side of the political spectrum."
],
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24,
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789nqw | Why do we say "dehydrated" instead of "Malhydrated". And "malnourished" instead of "denourished"? | Other | explainlikeimfive | {
"a_id": [
"dos3ca2"
],
"text": [
"Dehydration is the lack of hydration, whereas malnourishment doesn't mean you're not getting nourishment, just bad nourishment. One is the absence, the other is just low quality."
],
"score": [
15
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789udg | Why do cell phone batteries die faster the longer you own them? | Technology | explainlikeimfive | {
"a_id": [
"dos7dhl",
"dos5an0",
"dos5frc"
],
"text": [
"imagine your phone's battery has 100 cells in it brand new. when those 100 cells are fully charged, your phone's charge is at 100%. 3 cells lose their charge as you use it to browse eli5, 97%. now, those cells have a lifespan. after 3 months, 2 cells completely die and no longer can hold a charge at all. so now you have 98 cells in your battery. when those 98 cells are fully charged, your phone is at 100% because all available cells are fully charged. but that 100% won't last nearly as long because there are 2 less cells holding that full charge. so it'll get to 0% a bit quicker than it did with the full cells. so when 10 cells die off, you now have 90 cells holding a charge instead of 100. i made up all these numbers to paint the picture for you.",
"You store energy due to some electrochemical process. You put current in, the process happens, you take the current away and you can over time get some out due to the process now being reversed and happening on its own. Imagine you store energy in a spring made from metal. You draw it out, then put it in some mechanism that takes the energy out of the spring again to power something. You can put energy back into the mechanism by pulling the spring again. Repeat this a few thousand times and you'll notice that the spring isn't working as well anymore, the material has gone tired, wear has stretched it out a bit so it can store less energy than when it was new. Just imagine the same happens with your batteries. You load and discharge it so often that whatever is used in the elecrochemical process (the electrodes, the electrolyte in it etc) gets tired and stops working as well and can store less and less energy. If your battery could store energy to last your phone for 8 hours at the beginning it might be it's down to six or five after some years. Here's an [image]( URL_0 ), the details are not really important here, just to see what could simply not \"work so well\" anymore.",
"Think of rechargeable batteries like balloons. You inflate them then you let them go and they whizz delightfully around the room or in the case of batteries allow you to flit around Reddit. Anyway, balloons, like anything elastic, eventually lose their stretchiness and you cant use them anymore. Batteries are very similar. The exact cause of the decrease in storage capacity from repeated use varies between different battery chemistries but the end result is the same, less Reddit per charge."
],
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"https://www.researchgate.net/profile/Mohammed_Farag3/publication/306240899/figure/fig7/AS:396045998673928@1471436132318/Figure-27-Schematic-representation-of-a-Li-ion-battery-during-discharging-7.jpg"
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789zcj | What happens above the clouds during a tornado? | Other | explainlikeimfive | {
"a_id": [
"dosm74i"
],
"text": [
"Mostly turbulent winds that calm down the higher you are above it. Tornados are caused by thunderstorms often characterised with the forming of Cumulonimbus clouds (Referred to in their short code as \"Cb\" or nicknamed \"Charlie Bangers\" by pilots) which can rise extremely high in the atmosphere. They can get as high as 48'000ft! They are extremely dangerous to go anywhere near in an aircraft and we avoid them like the plague. Generally speaking it's quite hard to be above a cumulonimbus cloud as they rise so high, but if your above the clouds then generally your above the weather, so it's a lot calmer. I've not had the opportunity to fly over a cumulonimbus cloud as yet. I am not sure I want to either. But looking down it would likely be hard to tell there was a tornado happening at ground level."
],
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789zy7 | How does milk stay fresh and not go bad before being put on a store shelf? | Other | explainlikeimfive | {
"a_id": [
"dos7cn1"
],
"text": [
"After milking the cows they process it and then chill it. it's shipped in refrigerated trucks. Milk is actually heated first as pasteurization is part of processing. pasteurization kills bacteria and microbes in the milk. It may be skimmed (removing fats for butter, cream, etc and to make the types of milk 2%,skim, etc), homogenized and fortified as well before bottling and shipping. while milk left out warm will eventually spoil it's not like it will instantaneously go bad if it's not chilled."
],
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|
78a0bj | Why do people twitch, or jump, while they are falling asleep? | Biology | explainlikeimfive | {
"a_id": [
"dosaj08"
],
"text": [
"Ah I hate these! It's a called a hypnagogic jerk and they occur during the transition between being awake and asleep. There are a couple of theories for them, such as accidental neuron misfiring, but I like the evolutionary approach to the phenomena. The theory goes that the jerk originates from our origins - when we may have been resting up in trees and hiding from predators. Accidentally falling asleep in these conditions would definitely benefit from this sudden hypnagogic jerk so we could quickly grab a branch to stop us falling out."
],
"score": [
10
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|
78ac72 | What is the purpose of yawning? | Why do we yawn? I've never understood the reason for it. If it's to refresh our breath, why isn't this covered through normal routine breathing? | Biology | explainlikeimfive | {
"a_id": [
"dosopkv",
"dos99ct"
],
"text": [
"URL_0 We don't really know. It may have a variety of functions as have been proposed, or simply be a left over feature which has no function now.",
"The brain occasionally needs more oxygen than usual (especially when we are exhausted). Yawning helps as it allows your body to get more oxygen than it usually gets when you breath normally."
],
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[
"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3678674/"
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78ao8b | What happens in our brains when we try to remember something but dont and then randomly remember it some time later? | Biology | explainlikeimfive | {
"a_id": [
"dosg2sm"
],
"text": [
"When your conscious thoughts move on to a different subject, your subconscious is still looking for different connections to that memory. So you’ll be thinking of something different and then suddenly remember what you were trying to."
],
"score": [
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78b6mr | Stephen Hawking’s Properties of Expanding Universes | Physics | explainlikeimfive | {
"a_id": [
"dost7fz"
],
"text": [
"His thesis was just released and it is basically what he has been studying to prove since 1966. It considers the implications and consequences of the expansion of the universe, and its conclusions include things you may have seen as news on Reddit before, e.g. that galaxies cannot be formed through the growth of perturbations that were initially small. Krauss, another physicist who works closely with Hawking, has done work based on Hawking's thesis and found that there is not enough visible matter to hold galaxies together. This led to the theory of dark matter, an invisible *something* that accounts for the missing matter causing the gravitational pull. It has had many developments over the years, and it is essentially Hawking's original proposal which started all these new theories going. Using math and all kinds of complex analysis, there is credence to the theories which are simply thought up by these physicists to help us understand the universe better. It leads to more questions but we get many interesting (and often bizarre) answers thanks to the work they've put in to making new breakthroughs in scientific understanding."
],
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78b6us | Why do pain killers like tylenol or paracetamol make flu shots less effective? | Biology | explainlikeimfive | {
"a_id": [
"dosja5b"
],
"text": [
"Paracetamol works by stopping your body from making chemicals that naturally increase blood flow by dilating blood vessels. When you get a big bruise that's swollen, these drugs reduce the blood flow in that area, which helps reduce swelling. If you've gotten a flu shot after taking a bunch of drugs like this, there's less blood flow at the site of the injection. The contents of the shot can't as easily get into your blood stream. We do the same thing if you need to get an injection of a numbing drug -- except we use another blood vessel constrictor, epinephrine, which stops the numbing drug from spreading farther than we want."
],
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5
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78bfiz | If Uranium has a half life of 4.5 billion years, why do Uranium fuel rods used in nuclear reactors need to be replaced every six years? | Physics | explainlikeimfive | {
"a_id": [
"dosia1p",
"dosjhpa"
],
"text": [
"Because half life is from natural decay, not fission. Inside a nuclear reactor, we're actively causing the fuel atoms to split at a much higher rate than decay would happen in nature. Plus there's also a significant difference between natural decay and atomic fission.",
"Uranium-238 has a half-life of ~4.5 billion years. However, Uranium-238 is not what drives a nuclear fuel cycle. Uranium-235, which has a half-life of about 700 million years, along with some other isotopes are the primary fuels in most nuclear reactors. Some nuclear reactors are designed to operate on refined Uranium with its natural isotope balance, while others require the fuel to be enriched by increasing the proportion of Uranium-235 in the fuel. Yet more reactors permit new fuel to be mixed together with old fuel, burning it again. What makes U-235 so different from U-238 is that U-235 is a fissile material whereas U-238 is not a fissile material. In the right concentration, and under the right conditions, fissile materials are capable of sustaining a fissile chain reaction. Fissiling is different than simple radioactive decay. Over time, Uranium-235 will naturally undergo alpha decay into Thorium-231 absent any external intervention. However, if a Uranium-235 atom collides with a thermal (slow) neutron, the atom can literally be blown into pieces. A single Uranium-235 atom may be broken into Barium-141 and Krypton-92 along with three free neutrons. If these neutrons are then slowed down, they can further interact with more Uranium-235 atoms. On the other hand, Uranium-238 naturally decays into Thorium-234 over billions of years. However, unlike Uranium-235 Uranium-238 does not fissile with thermal (slow) neutrons. Instead, it captures them and becomes Uranium-239. Uranium-239 Undergoes beta decay into Neptunium-239 which in turn undergoes beta decay into Plutonium-239, a useful isotope in nuclear weapons. However, Plutonium-239 can capture slow neutrons and become Plutonium-240, a temperamental waste product. Just for the sake of completion, the radioactive particles emitted by alpha decay (two protons, two neutrons, or a helium-4 nucleus) and beta decay (electron) are not sufficient to start or sustain most fissile chain reactions. Spontaneous fission in Uranium isotopes is rare but does occur so care must be taken to keep concentrations of fissile material below a certain threshold. In summary, nuclear reactors aren't powered by the natural radioactive decay of their fuel, but rather by a chain reaction caused by neutrons flying around colliding with fissile material causing said fissile material to break into pieces which in turn causes more neutrons to fly around. The rate of this reaction must be carefully controlled."
],
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78bppr | If the melting point for both fat and wax is around 40°C, why does rendering fat take hours, and candle making takes minutes? | Chemistry | explainlikeimfive | {
"a_id": [
"dosna31",
"dosqvux"
],
"text": [
"There is something called Specific Heat, which is the amount of heat per unit mass required to raise the temperature by one degree Celsius. It is a property of the material, so wax and fat have different specific heat capacities. For the same mass and temperature change, a material with a higher specific heat would require more heating to reach the temperature differential. There is also the heat of fusion, which is the energy required to change a gram of a substance from the solid to the liquid state without changing its temperature (assuming you heat both to 40º and keep it there). If fat has a higher heat of fusion, it would take more energy to melt it completely if you keep it at the same temperature, which means it would need to sit longer over a burner or in an oven.",
"It takes more energy to get fat to 40 C then it does to get a candle to the same temperature. For a more intuitive example, think about cooking, say, a large chicken in a metal pan in an over. It might only take minutes to get the metal in the oven up to 350 degrees, but it will take hours before the whole chicken is at that temperature."
],
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78c429 | Is it theoretically possible for earth to be STD free in a generation if everyone stopped having unprotected sex? | Biology | explainlikeimfive | {
"a_id": [
"dosnogo"
],
"text": [
"If everyone stopped having unprotected sex, the human race would end in a generation. So, from that perspective, yes, no more STDs."
],
"score": [
5
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|
78c9qs | Why do European forests seem to have less underbrush than forests in the Eastern U.S.? | Biology | explainlikeimfive | {
"a_id": [
"dosppr9"
],
"text": [
"Im no expert but I believe its because they've been left alone to grow longer, when trees get bigger it cuts off sunlight to the floor, over time you get a lot less smaller plants in the underbrush due to that and maybe the bigger trees using up more nutrients. I recall reading that in USA it used to be possible to ride a horse through the forests easily because there was much less underbrush to deal with. Then practically all the forests were cleared at some point and in most places once they get big enough loggers come through and do it again. Also most forests in USA arent entirely natural, certain varities of trees are planted for certain purposes and it's never with the goal of recreating a naturally occuring forest environment. Could be wrong or lacking info but that's my understanding of it."
],
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|
78ca8n | Why does steel wool burn with a match or when touched by a battery, shouldn’t it melt or not burn at all? | Chemistry | explainlikeimfive | {
"a_id": [
"dosph5g"
],
"text": [
"Iron only melts at very high temperature so a match can't melt it. Iron reacts easily with oxygen: rust is just iron oxide. Reactions work better and faster at higher temperatures. If iron is made into a form where it has a very large surface area, as with steel wool, then a little surface rust is affects all the iron. Heating it up speeds up the rusting which then releases enough energy to maintain the heat and this chain reaction is what fire is. Normal rusting of steel releases heat too but it's so slow and spread out over a large area that it's not noticeable."
],
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|
78cdl6 | What is spiciness? It must be more than just a flavor because you can "taste" it with any/all of your orifices. | Chemistry | explainlikeimfive | {
"a_id": [
"dospzoi"
],
"text": [
"What it is is capsaicin (8-methyl-N-vanillyl-6-nonenamide). It's the chemical that makes chilies hot and it's an irritant for mammals as well as a good fungicide. Chilies produce capsaicin to discourage mammals from eating their fruit, because a mammal's gut will destroy their seeds. Chilies depend on birds to spread their seeds, and birds are not effected by capsaicin. Humans eat chili fruits because we are deeply weird mammals who enjoy the spiciness. Capsaicin is also the active ingredient in pepper spray."
],
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9
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|
78cox6 | How do your veins stay in place? | everyone has veins in their hands but how do those veins stay in your hands as you grow olde? and what happens if a vein gets moved away from it's designated location? | Biology | explainlikeimfive | {
"a_id": [
"dosuanc",
"dosu7qn"
],
"text": [
"> everyone has veins in their hands but how do those veins stay in your hands as you grow olde? Blood vessels are embedded in tissue which keeps them in place. Each vessel has an outer layer called the \"tunica externa\" which anchors it to the surrounding tissue and organs",
"The outermost layer of your blood vessels is called the tunica externa (literally \"outer coat\") and is made primarily of collagen it, along with supporting lamina, anchors your blood vessels to the surrounding organs and tissues, holding them in place. Big blood vessels are fairly elastic and can move and stretch, as well as grow and shrink over time depending on the bloodflow needs of surrounding tissues. It takes a pretty strong shock to dislodge a sizeable blood vessel from its position. If they do break loose it can result in hemorrhaging (broken blood vessels) which can be very dangerous. And it may require intervention by a surgeon to repair and re-secure the vessel in the proper place."
],
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78crcb | Why are some people's hands naturally cold? | Biology | explainlikeimfive | {
"a_id": [
"dostst9",
"dostzbk"
],
"text": [
"Bad blood flow... normally their toes will be cold too. Anemia also causes this.. which is low iron. Although I think there are two types of anemia. My hands are alllwaays cold.",
"[Raynaud's Disease]( URL_0 ). I have it! When I get stressed my fingers (and sometimes toes) go numb."
],
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[],
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"https://www.mayoclinic.org/diseases-conditions/raynauds-disease/symptoms-causes/syc-20363571"
]
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|
78ctnz | What benefit does a game being a console exclusive have? Wouldn't reaching a wider audience on all platforms make more money? | Economics | explainlikeimfive | {
"a_id": [
"dosu65i",
"dosylw0",
"dosui60",
"dosu5ht"
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"text": [
"Third party exclusives are almost always contracted by the console manufacturer. While this limits the developer's audience it guarantees income granted by the contract plus sales. So the benefit is guaranteed income, a known quantity, versus gambling on a bigger pay off with a riskier unknown quantity.",
"1) development-wise - it's easier to program for one platform (think trying to translate with 100% accuracy across 5 languages...it's harder than you think) - after a game is a success you might put time and effort into trying another platform. Just look how many games are made for the Windows OS elusively. Now...how many games are ported to Mac or Linux (or other OS's?) 2) As mentioned by others - sometimes part of the deal for being ALLOWED to publish for a proprietary system the game system manufacturer will demand an exclusive release. Recall HALO? It was originally designed to be a Mac game (and then Windows). Not exactly the same - as Microsoft BOUGHT the gaming company (Bungie). Why?...so that the game would be exclusive on the X-box system (at least @ start) 3) Why would the manufacturer was this? - being the only game system in town to offer the coolest games means more people playing on YOUR game system platform.",
"console exclusive means you only have to make the game run on 1 device, so your testing is vastly easier. you don't have to test the game runs the same on multiple different hardware configurations. making money is a secondary consideration after making sure the product works. If you target everything available, you have to spend a fortune testing on all those different things, which means you have to make even more money to break even. source: im a pc dev. testing is is most of the work",
"I don't claim to understand how the industry works but logically speaking. It would make sense for console makers i.e. Sony or Microsoft to reach out to developers to get exclusivity. The deals they broker obviously would help the game developers in some way. Perhaps a cash incentive."
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78cvjf | If one of the world's top medical journals classifies fluoride as a neurotoxin, why is it safe to consume in our water? | URL_0 | Chemistry | explainlikeimfive | {
"a_id": [
"dosv8ww",
"dosv3bs",
"dosy0b4"
],
"text": [
"Everything is toxic in a high enough dose. Both salt and water will kill the shit out of you in high enough doses, but are also necessary to life. Any publication that talks about toxicity without providing dosage information is spouting nonsense. Lets demonstrate why dosage is important: Sodium chloride - LD50 3000mg/kg - Death by extreme hypertension, heart attack. Dimethylmercury - LD50 0.05mg/kg - Potent neurotoxin. Goes right through most protective garments. Will hurt the whole time you're dying. Both of those things will kill you, but I have 2kg of one of them in my pantry, and I wouldn't want to be on the same continent as 2kg of the other.",
"It's all about the levels. Flouride in water is at levels of under 1mg per liter, it doesn't become toxic until you're consuming grams at a time.",
"Your source referance a harvard meta study from 2003. That meta study found that high dosages of floride in rural chinas well water cause a .53 decrease in IQ of children. The dosage in question is much higher than American tap water. It is safe to consume because of dosage. The upside are stronger teeth and fewer cavities. Thats the only study inside an very bias article, and it doesnt directly link to the paper it links to a huffinton post about the paper. I wouldnt trust this web site."
],
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78cvtj | Why is emergency lighting dim red? Wouldn't you want it to be well lit in a disaster situation so people can see where they're going? | Biology | explainlikeimfive | {
"a_id": [
"dosuo6i",
"dosuwb3"
],
"text": [
"many backup lights are bright white. but one intent of dim red would be to preserve night vision since your likely to encounter unlit areas, so just provide enough light to help without ruining you in the dark spots.",
"Emergency lighting is often running on backup generators or batteries. That means that power consumption is a serious issue. Dim lights provide enough illumination to navigate the space, while consuming the minimum amount of power. Red light doesn't interfere with night vision. This is why you often see red lights in aircraft cockpits and on the bridges of ships. It provides light to read charts and instruments by, without blinding the crew to the outside environment."
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78cz79 | If fluoride is good for your teeth, why don’t we use it to strengthen our bones? | Chemistry | explainlikeimfive | {
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"For one, your bones aren't covered in enamel. And if they were, you'd have to apply it to the surface of your bones. If you're not Wolverine, then that's not gonna work out.",
"Because Teeth aren't technically bones. They are almost entirely calcium, as opposed to bones more carbon based structure. Fluoride in water specifically targets your enamel, and helps strengthen it, which is great. It is in low enough quantities to not come near any of the health effects listed in that other guys study in municipal water anywhere. Bones don't really have enamel, so it wouldn't strengthen them, and as the other guy did correctly point out, its pretty bad for you in large quantities (like what you would need for bones if it did work)."
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78d9bz | Do multivitamins and Omega-3 pills actually do anything? or is it more of a placebo-type thing? | Biology | explainlikeimfive | {
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"**TL;DR**: *Depends on whether you have a terrible diet or a good (or even average) diet. They only really help if you have a complete absence of some nutrients; you'll get enough to get by if you eat a variety of non-junk foods like most of us do.* With a terrible diet, such as if you're a senior citizen that can't cook and eats very small portions or you live off of low-end ramen noodles or something, you're simply missing out on a ton of nutrients, particularly vitamins but also protein and fibre. Since you're not eating any greens or organ meats at all and stick to inexpensive pre-prepared foods with soft drinks on the side only, you're not going to get any Vitamin A, C or K, for example. The first is important for a lot of stuff like vision and immune system, the second helps keep your blood systems healthy, and the last is critical to avoid a condition known as scurvy (but doesn't actually do much else despite what the marketers tell you). (Omega-3's are needed in there too, but it's kind of overstated as to how much they help unless you have cardiovascular issues. Bad if you don't eat any fish at all ever, usually okay otherwise if you get a trace of 'em from that Tuna Helper casserole or have anchovies on that pizza.) And there's lots of similar vitamins that can be missed if you go the other route and stay completely uniformly vegan too. So if you have a really shitty diet, that once-per-day vitamin pill gives you SOME of those vitamins when otherwise you don't get any at all. That's good and helpful... ...but most people don't need them if they have a mixed salad once in a while or eat \"fortified\" foods which have them added. In that case, they get arguably limited value out of multivitamins.",
"It's very difficult to get scientific evidence on this. A person who takes the vitamin pill every day is quite likely looking after themselves in other ways too. For a comparison group, you'd need a variety of people living off things found in trash cans and lighter fluid, but who still remember to take the vitamin pill every day. I've heard the phrase \"If you can afford vitamin pills, you don't need them\", meaning your diet is likely enough to provide you with vitamins. It's also debatable how well the vitamins get absorbed in pill form.",
"Vitamin D is typically included in multi-vitamins as well, although the dosage is inadequate for anyone who may need it in a dietary supplement. We get vitamin D naturally from exposure to daylight, so some people in northern latitudes (or anyone who spends way to much time indoors - talking to you Reddit) can avoid a variety of conditions related to vitamin D deficiency. Buying just vitamin D is a small fraction of the cost of multi-vitamins.",
"Yes they help, but it’s obviously way better to eat a balanced, nutritious diet. It can’t hurt (if you take the recommended amount). Don’t waste your money and buy some cheap Kirkland ones on Amazon.",
"Science Vs. just did their weekly podcast about this very question. You should give it a listen. The conclusion on multivitamins was that they don't do much, but they also do no harm, so why not.",
"[Science vs.]( URL_0 ) podcast just did a show on this. Scurvy and Rickets are diseases that were very real in the not too-distant past. These were due to a lack of Vitamins C & D. Today these conditions are very rare because we understand them and have vitamins added to common foods. The science on long term benefits of vitamins is a mixed bag without any clear answers. The best they could come up with is that there is good scientific evidence that taking a multivitamin a day isn't going to have any negative consequence."
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78db69 | Are the waves that we see and the waves that we hear the same wave at different frequencies? | Physics | explainlikeimfive | {
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"No. We see electromagnetic waves, which are pairs of transverse (up and down) waves at right angles to each other and are transmitted by photons. They vary in wavelength from thousands of kilometres (10^(6) metres) down to picometres (10^(-11) metres; smaller than atoms) with visible light being in the nanometre range. We hear mechanical waves, which are compression (back and forth) waves and are transmitted by atoms or molecules bumping into each other. They vary in wavelength from a few metres to a few millimetres. Wholly coincidentally, the range of light with a wavelength of a few metres down to a few millimetres is mostly used for radio communications."
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78de54 | Are sensors mechanical or programmed responses? | My SO and I are at a standstill and I need some help. We recently watch "Ex Machina" and started a discussion regarding the AI's skin and how it would work. I believe that the AI's skin would be like our own, as I understand, and built on a redundant system of tiny sensors that would be stimulated to send an electric signal to the brain by design. My SO is arguing that the sensors must be "programmed" so that the signal is transmitted upon stimulation. The point I'm making is that "programming" is not needed if the skin is built/designed to respond to stimulus and the process is mechanical. I would like to know how if using "programming" as a way to describe the process of skin sending signals to the brain is either incorrect or correct. | Technology | explainlikeimfive | {
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"If it's an electromechanical device that can only do one thing, it's *designed*, not programmed. I mean, it's a completely fictitious device, so we can only speculate as to how it'd actually be built. There could be some programmable device in there that collects input from all the individual sensors & then relays that as a signal to the central processor.",
"It'd be more apt to describe the brain as programmed to interpret certain sets of electrical signals as pressure, pain, heat, etc. Our own skin reacts in such a fashion. Nerves aren't \"programmed\" to do anything. They simply react to stimulus and produce electrical signals the brain later interprets. Mechanical sensors can be built the same way. Thermocouples, for example, do not require any programming. They get hot, they produce an electrical charge. It's a purely physical process. Piezoelectrics are similar. That isn't to say you can't program a wide variety of sensors to react to different stimulus. Really I suppose it would come down to the unique requirements of your synthetic skin."
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78dkkf | Why does sugar never spoil? | I know it has something to do with its moisture content, but what about sugar makes it so good at not absorbing moisture? | Chemistry | explainlikeimfive | {
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"URL_0 The reason is the opposite. Sugar IS really good at absorbing moisture. In fact, it absorbs moisture so well that any bacteria present on the sugar will literally have their water sucked out of them and into the sugar, causing them to die.",
"sugar itself doesn't have any hydrophobic qualities. however, it does have some antimicrobial properties especially when processed by \"harmless\" microbes. URL_0 URL_1 also, sugar doesn't have a natural decay rate detectable by humans like lipid rancidification"
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78dquw | Why wouldn't prop planes require counter torque when helicopters do? Does it have to do with the plane's mass? | Physics | explainlikeimfive | {
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"Look into trim tabs and what they do. Prop planes will typically have a little tab that sticks out of an aileron and one side of the rudder. These are there to make fine adjustments to trimmed flight. These also offset the torque created by the motion of the prop. Also, when a single engine prop plate increases power, there is a corresponding rudder input (typically to the right) to offset the torque on the fuselage. The wings, fuselage, horizontal and vertical stabilizers also counter these forces. These are control surfaces that helicopters don't typically have.",
"Propwash and wings. The air spirals backward toward the tail of the plane. This provides stabilization as it passes over/under the wings. The pilot will the trim the aircraft out by adjusting the aileron's trim-tabs(not flaps like suggested). The Propwash actually helps provide lift too. A plane can actually fly slower than the minimum controlled speed or Vmc when the aircraft is close to the ground, while the plane is in \"ground effect\". The Propwash spirals the craft and hits the ground causing a simulated lift on the wings. Very useful to know if you need to make a steep climb-out or if you are executing a short - field takeoff. Helicopters do not have wings, therefore the torque must be mitigated with the tail rotor.",
"All propeller driven aircraft display left turning tendencies due to three forces from the prop. One is torque, think Newton, for every action there's an equal opposite force. So the prop turn to the right, the plane tries to twist left. The propeller isn't contacting the air in the same way on the upswing as it is on the down swing. It has to do with how airfoils create lift in relation to the air's angle of attack, and each blade on the prop producing a different amount of lift depending on which side it's on. This causes the right side to produce more power than the left side, so the plane tries to turn left. The third cause is the wind the prop is producing itself. This wind twists around the aircraft and winds up hitting the vertical stabilizer and rudder. This again causes one side to produce more lift than the other. Except that this time it's not different blades on a propeller, it's different sides of the vertical stabilizer and rudder. This too causes the plane to want to turn left. All of this is taken into account during the initial design phase of the aircraft. Pilots know this is happening too and know to adjust rudder trim, if the plane has it, or to step on the rudder a little during high power, low speed flight. Source: SEL pilot.",
"All the people in here talking about \"flaps\" are going to give me aneurysm. Here's a very brief Into to Flight Dynamics: Ailerons: A control surface mounted on the trailing edge of the outboard section of the aircraft wings. These control surfaces move up and down opposite to each other and allow roll along the longitudinal axis. This movement is called \"roll\" and is the primary method for changing the aircraft's direction Elevators: A control surface mounted on the trailing edge of the horizontal stabilizer on the tail of the airplane. This control surface moves up and down, usually together (some fighter aircraft have independent stabilizers for advanced maneuvers). The allows the the aircraft to rotate along the lateral axis, which moves the nose up or down. This movement is called \"pitch\" and is the primary method for changing the aircraft's altitude. Rudder: A control surface mounted on the trailing edge of the vertical stabilizer on the aircraft's tail. This surface moves left and right and causes the nose of the aircraft to swing about the vertical axis. This movement is called \"yaw\". Yaw is a somewhat complicated movement and basically has to do with prevented the aircraft for slipping or skidding, which is when the direction of movement does not match the direction the nose is pointing. Flaps: A secondary control surface that extends aft and down from the trailing edge of the wing surface. This changes the shape of the wing and drastically increases drag and lift, and causes the nose of the aircraft to rise. This allows the aircraft to land and take off at much, much slower speeds than would otherwise be possible. Yaw is the movement we are worried about here. All propeller driving aircraft will tend to yaw on takeoff and climbout due to a torque effect from the propeller(s). This yaw is offset by applying a slight rudder trim to produce a counter force equal and opposite to the torque steer. Watch a video of an old C-130E or C-130H take off and sometimes you can see that the aircraft is trying to pull to one side. It is most evident in max power short airfield take offs."
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78du7d | what, biologically speaking, are shivers/the chills that run through your body? | Biology | explainlikeimfive | {
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"From what I've gathered over the years. (Wondered this myself many times. And I am in no way a prof in this area) We get the sudden feeling of chills when our muscles expand and contract suddenly, stimulating our nerves, more often than not around the sensitive spine. That's just for basic random chills that happen for any number of reasons. Could be a fever, could be a tight muscle and your body is trying to subtly fix it, and more. Now \"emotinal chills\" as they've been coined are much different. Emotional Chills are caused by a number of factors as well. The most common one nowadays thanks to phones and the internet, is music emotional chills. More than 50% Of the US Population has reported these. Musical Chills are typically caused by dopamine build up. When you hear an amazing song and the pitch and lyrics are just....right. There's always that little edge of \"this could be better in some way\". Then it hits. Whether it's a music score or a certain lyric or pitch, your body had been anticipating it and caused a dopamine build up which we'll, Charlie Sheened inside your head. This sends pleasure, chills from the happy ecstasy stimulation. Putting it bluntly, your mind orgasmed and it dribbled through the spine and your body. That's usually the case for music, art and beauty have other factors depending on what it is. TL;DR Normal chills are caused by muscles rapidly expanding and contracting caused by many factors. Emotional Chills are usually caused by brain chemical stimulation from all sorts of emotions"
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78durg | How did the crash of the mortgage markets result in people unrelated to the housing industry losing their jobs? | I get how the housing crisis resulted in a banking crisis but how did that result in massive unemployment? | Economics | explainlikeimfive | {
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"When you put money in the bank, the bank loans some of that money out. Most of it, in fact - it's common to keep less than 10% of deposits in cash, since most people bank electronically most of the time. So, when you put $100 into the bank, the bank lends out $90. Now, what's interesting is that that $90 also winds up in a bank. The person who borrowed it probably used it to buy a car or a house, and the person selling that car or house deposited the money. So, the bank can lend out $81 more. This carries on until the actual amount of cash the bank possesses matches what percentage of accounts they keep in cash. So, in this case, for a bank that keeps a 10% reserve, your $100 in cash is now shared between $1000 in accounts. This phenomenon is referred to as 'imaginary money'. We treat imaginary money just like real money, and 90-95% of the money in your bank account and that you spent today was imaginary money. When the mortgage crisis hit and defaults came in, the bank wasn't refunded for the houses it helped to buy. Before, it had $100 in cash, $900 in accounts receivable, and $1000 in obligations. But post crash, it only might have had $100 in cash, $400 in accounts receivable, and $1000 in obligations. In order to get back to it's reserve rate, the bank had to stop issuing loans for a while, until accounts rose. So, when one of the people who owed the bank money made a payment, say $100, the bank still only had $100 in cash, but $300 receivable and $900 in obligations. Effectively, the imaginary money that people were using to pay their mortgages was leaving the economy - the money supply shrank. The total amount of money in bank accounts went down. With fewer dollars around, people start to feel the crunch. At first, this was noticed near the outflows where money would normally leave the bank - people getting loans. But those same people were buying fewer things, and hiring fewer people, and that meant that the money shortage spread outwards, to all other sectors. One of the typical solutions debated during recessions is called 'quantitative easing'. Basically, the government prints new real dollars to replace the missing imaginary money. The government basically prints money and uses that money to buy back debt it owes, transforming treasury bonds into real money. During the Wall Street Bailout, the US government bought back bonds owned by the major banks and stock trading companies. This helped a little, but you'll find a lot of arguments that it could have been done better. I won't get into those here. TL;DR: Economics is complicated like rocket science but basically mortgages create imaginary money, and when you default the bank needs to fix it's numbers and that reduces the amount of imaginary money, which makes money harder to get while the banks soak it all up to replace their losses.",
"Banking crises can have flow on effects because of how integral banking is to modern business. For example, lots of businesses borrow money on relatively short timescales to have the cashflow to pay employees. When the banks get hit by a crisis and don't have enough money available, they can't lend out money. Borrowers can't find the money they need to pay employees, and have to make them redundanr instead.",
"Most business owners are consistently running in the red. No they are not in debt. That are in a perpetual deficit. Where they technically are $1,000 in the red. But realistically if they cut a little of this and a little of that they are perfectly fine. Business owners do this because its a really great way to expand and grow. Yes you went a thousand into a red this week, but next week you'll be making three thousand because you added more staff or made improvements to the company. In order to do this owners were always in a state of Borrowing money for those investments. Hiring on an employee, buying a new machine. Yes they were always borrowing but their company was booming and successful. and both them and the bank would see positive results. And then the banks lost money... ALOT of money. When a mortgage fails banks do take a hit but since they have hundreds of other people making payments. They are more then fine. When suddenly hundreds of thousands of people fail their mortgage... shit gets real bad. Then add in the fact that all of those failed mortgages are going to cause everyone elses mortgage to essentially fail. Well, that's a global crisis. And can result in annihilating the entire economy. Which it almost did. Because remember most businesses were in a perpetual deficit to grow. Suddenly not only could they not borrow, but now that had to pay in full for that deficit. Which depending on company could be a few thousand dollars to millions. Some companies had to liquidate alot. Some had to lay off a few people, some companies had to lay off everyone and sell everything. And because almost every business was in the red. nobody wanted to hire anyone... which meant people didn't have money to spend... Which caused a very vicious cycle until the big boys stepped in. And this is why crashes are a terrifying thing. Because until big boys come in to save the day... the entire economy is on a steady spiral to death."
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78e2cx | Why does the first cup of coffee in the morning makes you need to go the toilet | Biology | explainlikeimfive | {
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"There's the gastrocolic reflex, which stimulates bowel movement after food enters the digestive tract. Swallowing initiates smooth muscle contractions that push its contents on down and eventually out. Warm fluids are particularly good at stimulating this reflex, and it has a double-whammy effect if the fluids contain caffeine. Also, your digestive system doesn't stop working while you're asleep, so your poop pump is primed for action after a night's rest.",
"Caffeine acts as a smooth muscle relaxant through it's effects on cellular cAMP levels. Your intestines are surrounded with smooth muscle, and when relaxed will prompt you to go to the bathroom."
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78e5tk | How come glass breaks when it hits the ground, but marbles bounce and hardly take damage? | Physics | explainlikeimfive | {
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"Spheres. Spheres distribute the shock of hitting the ground very evenly. A marble can still break, but it's less likely to than a cube, prism, or sheet.",
"The shape of the marble helps, but it is less significant than the material properties. The manufacturing process of glass marbles creates beneficial compressive residual stresses on the outside of the sphere- this effectively \"prestresses\" the outside. Thus when you drop a marble on the ground, the forces are not enough to overcome the residual stresses, thus never allowing for tensile forces to initiate cracking. This is similar to what you see in tempered glass (the stuff the side windows of a car might be made of, which are harder to break than you might think). There is a youtube video floating around where a marble is crushed in a hydraulic press - it literally explodes, with all of the internal residual stresses being released instaneuously."
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78e6yi | How are artificial flavours made? How is a flavour replicated/created? | Chemistry | explainlikeimfive | {
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"A natural flavor from for example a plant is a combination of 100s of different chemicals. But it may be mainly just one of those 100s that give a distinct flavor. So you would analyze the plant, figure out the chemical structures of what make up that plant. This is done using different methods and is like solving a puzzle without a final picture. You have a bunch of pieces of Information and you try to see what they can make. Once you know what the structures that make up a taste are you can try to make a few. This is done using experience from the past on how to put chemicals together to get a certain result. For example we know if we have an alcohol, and we add oxygen, we often get an aldehyde or keytone, ( a double bonded oxygen instead of a single bonded oxygen). also alot of guess work. Maybe one of the structures you produce sort of tastes like what you want to flavour. Then you can produce that taste.",
"In addition to other answers, you have to realize that as far as the law is concerned, artificial just means created in a lab. Remember, everything is chemicals. You could for instance analyse all the compounds in bananas and find the one that causes its flavour and then replicate it in a lab. Even though it is 100% the same stuff, it'd still be classified as artificial.",
"Well, it turns out that beavers actually have really delicious anuses. Google it, go ahead.",
"Has there been a big improvement in cherry flavoring? The recent cherry coke / cherry Dr. Pepper / cherry 7-UP tastes like actual cherries now instead of Robitussin medicine.",
"URL_0 I can't explain it really but... it has something to do with known compounds that produce certain smells/tastes. Esters is what I was thinking of, but it looks like there are also Terpenes that do the same thing. If you go to the Wiki page you can see which compounds produce which smell.. it says they're also used in food to produce taste. There's probably a separate page for tastes somewhere.",
"My dad was a Master Flavorist (retired) for McCormick for 40 years. He definitely had an incredibly interesting job. More than happy to ask him some questions if anyone wants me to"
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78erng | How do defibrillators work? | And is it possible to repeatedly stop or start a person's heart using them? | Technology | explainlikeimfive | {
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"Haha at last something relevant to my work. I work for a company that makes defibs. So a bit of background about hearts. Hearts are basically a bag of blood surrounded by muscle. Muscles are activated by electrical signals. In normal muscles, they are activated by nerves usually coming from the brain, but in the heart the nerves come from a separate controller on the heart itself. So this central controller controls the heartbeats. _Fibrillation_ is when this central controller goes astray and uselessly quivers the heart. How to fix it? You can send a huge jolt of electricity through the heart, shocking it to reset back to normal. This is of course called **De**fibrillation. _Common misconception #1: you cannot use defibrillation to restart a heart in **ALL** heart attacks or cardiac arrests!_ Only in ventricular fibrillation (VF) and pulseless ventricular tachycardia. If the heart is completely stopped, using a defib won't help. _Common misconception #2: Automatic External Defibrillators (AEDs) that you see in malls or public places work like the movies; when you press the button, it will immediately jolt the patient._ Modern AEDs are much smarter nowadays, they actually analyse the heartbeat of the patient, and will advise if a jolt is warranted. So if you ever have to use one, don't panic even more because it didn't deliver the jolt like you expected. Last point: make sure that the skin of the patient is dry before pasting the electrodes on the skin. And of course don't touch the patient when the jolt is delivered. And to answer your question about repeatedly starting and stopping the heart, possibly not, although I'm not a doctor. Reason is that electrical shocks might completely stop the heart, which a defib will not be able to start again. Basically comes back to the specificity of conditions where defibs are useful. Disclaimer: I am not a doctor or expert. Always consult a professional or read the instructions for use.",
"Defibrillators actually don't start a heart. What they do is force the heart to return to a normal rhythm, in the case of dysrhythmia, such as tachycardia. This can prevent a heart attack from occurring, but it cannot restart a heart that has stopped beating."
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78g1vi | since Light can move from one location to another, does that mean it's movement carries a Force from the momentum? | ELI5: since Light can move from one location to another, does that mean it's movement carries a Force from the momentum? I was looking into Solar Sails, and how they use light to push off the sail, but if light carries a Force from momentum, shouldn't a flashlight be able to propel itself without any solar Sails? | Physics | explainlikeimfive | {
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"Light has momentum. However, the momentum of the light is very small in comparison to the mass of the flashlight. Sure, a flashlight would propel itself across outer space, it's just a lot slower than other things of that mass. Solar Sails have to be very, very large and very, very light. Such things can be built in space. Then you can make them go with a massive laser on the ground, or a star. Both of those power sources are much too massive to take with you.",
"Light (more specifically photons) has momentum it's just tiny, like really really tiny. In order to effectively harness that momentum the object needs to be extremely light-weight and the stream of light propelling it needs to be extremely strong. (think megawatt lasers or light from a star) A good historical example of radiation pressure (the formal name what you're proposing with a flashlight) is the [Pioneer anomaly]( URL_0 ) where the spacecraft was slowly pushed off course due to uneven radiation of heat.",
"This is basically like asking, \"If ships can sail from the force of wind, shouldn't I be able to propel myself from the force of my farts?\" Your mass is far too high for the proportionally tiny force of your farts. Probably. I don't really know you. The light coming from a flashlight is far too small (orders of magnitude too small) to propel a flashlight forward.",
"Yes. Photons have energy, or are energy depending on how you think of light. They have momentum, and that is transferred to objects like solar sails. A quick search for \"radiation pressure\" can give more details on the topic. A flashlight would have some force in space and would accelerate due to the beam. The force of the flashlight from emitting the beam would be small, but it is greater than zero.",
"Yes, but the momentum is so small that for light to move an object with serious mass even in space, solar sails are needed.",
"Everybody at some point has heard the term energy E = mc^2. If you use this formula for the massless photon you get E = 0 which is not true. That formula is actually the Energy mass relationship. As in mass is energy and vice versa. There is however a second relationship, energy and momentum where E = (PC)^2 + (mc^2 )^2 explaining anything further is out of scope for this forum but it's the relativistic equation relating restmass, and momentum. The term p is momentum. For the special case of massless particles E = pc. Everyone also knows that for force F = ma (a is acceleration). F can also be written as F = dp/dt (a small change in momentum over time). Wait but this means that if a photon has momentum then it can apply a force? Yes a great toy to show this is Crookes radiometer. URL_0 Also this means the idea of a solar flare is 100% possible but it's impractical. It would be good though for deep space exploration over thousands of years. I can explain photon pressure like you're 10 if anyone wants.",
"The flashlight can't accelerate to a measurable speed from its own light because its batteries won't last that long.",
"Other people have some good explanations of your main question. I'd like to just make a little note about the wording of your question. Forces exist only as the interaction between two objects. An object cannot therefore \"have\" or \"carry\" force. Inertia and momentum are things we can consider an object to \"have\" that are sometimes meant when people say \"the force of\" an object. I like to keep this straight by always referring to a force as \"The force object A exerts on Object B\", so it's really clear which two objects I am saying are pushing or pulling on one another. For example, my weight is a result of the force Earth exerts on my body. A car skidding to a stop is a result of the force the road exerts on the car's tires. Thinking of it this way can help us not get tricked into thinking a force exists when it does not or confuse force for another thing that might be involved.",
"To the best of my knowledge, photons do not have mass. There are some specific situations in which they may have mass, but we will ignore those here, focusing on how they behave most of the time. The reason they don't have mass (as touched on by another poster) is that the concept of mass is really the interaction between sub-atomic particles. The Higgs-Boson particle is our current hypothesis for the source of mass. As an analogy, think about how different molecules are made because or the interaction of different atoms. Carbon dioxide is very different from carbon monoxide because of the number of oxygen atoms each has, and how they interact with each other. Now we can think about extending this example to look at hydroxide (one hydrogen, one oxygen) and carbon monoxide (one carbon, one oxygen). In both cases, the oxygen is identical, it's just the atom it's paired with that changes. Therefore, we can conclude that the changes we see in how these pairs behave is due to the components that make up the pairs! In the same way, the Higgs-Boson (I'm gonna call it the \"mass particle\" from here on out) interacts differently with things like photons and protons. For some reason (we're not quite sure yet, there's lots of theories) the mass particle interacts with protons in a way that makes them \"heavy\" and they resist moving. That's the basic effect of mass: massive stuff doesn't like to move. The mass particle interacts either not at all, or very lightly with photons, so they don't usually have a mass we can measure. Now, this doesn't mean that photons shoot around the universe and never hit anything: they'd be useless and we wouldn't see them! Instead, photons interact with the electromagnetic fields around them, instead of the gravitational fields. So, when you move a mass particle (like a proton) it creates a change in the gravitational field nearby. When you move a photon, it creates a change in the electromagnetic field. Now, this is why electrons and protons are really cool: they affect BOTH the gravitational field AND the electromagnetic field (and are affected by it as well, Newton pointed out that all forces in the universe are equal and opposite). With things like solar sails, the energy of a photon (massless) is absorbed; energy is just the basic raw building block of the universe. This gets into the limits of my knowledge, but there's an incredible book that covers the topic I'm reading, \"the incredible lightness of being\" that delves into the theory of quantum chromodynamics. They theorize that there's particles called \"color gluons\" that bridge this divide between massful particles and massless particles, and allow them to interact over distance. It's pretty fascinating :) If you have any follow-up questions, I'd be happy to try to answer them, or at least point to a resource on the topic! And I'm certain the comments will point out where I've gone off the rails ^_^",
"Photons are the carrier particle for electromagnetism. Not only do they have force, in a sense they ARE force.",
"p = m*v is an approximation of momentum that is true for macroscopic objects (like baseballs, planets, etc.). & nbsp; The more general way to find the momentum of something is to take the planck constant, 6.626 * 10^-34 J*s, and divide it by the objects wavelength (macroscopic objects also have wavelengths, it's called particle wave duality). & nbsp; So a photon with a wavelength of 1 picometer (10^-12 of a meter, smaller than the diameter of an atom), which is a very short wavelength for light, would still only have a momentum of 6.626 * 10^-22 kg*m/s. If you were an average size person walking at an average speed you'd have about 100 Septillion times (10^23 ) more momentum than that photon.",
"Yes. But i'm afraid you vastly overestimate the momentum of a single photon. I've done a quick calculation, the \"recoil\" force of a flashlight with an output light power of 5W is about 1.66*10^-8 Newton. If this flashlight had a mass of 1 Kg and was floating in space, it would take almost two years to accelerate to a velocity of 1 meter per second. Edit: Mixed up angular frequency with ordinary frequency and was a factor of 2 Pi of. Fixed."
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78g9h0 | Why do we want to sleep the whole day, and then in the evening... boom! No sleep at all? | Biology | explainlikeimfive | {
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"We have hormones that control this Usually these hormones are influenced by daylight to build up the need to sleep. An offset to this cycle makes us unbalanced, sleepy during the day and awake at night Lots of things can create this offset.",
"For me, it’s the fact that I am not ready for the current day to end, nor for the next day to start. This happens a lot when you hate your job",
"Side question. How much of a toll does rotating shift work (days one week, nights the next) take on the body?",
"A lot of it is habit, but also light from tvs, tablets, phones, and especially video games, fool your brain into thinking it's daytime. So if you stay up a lot playing Skyrim until 3 AM often, your brain is going to consider that daytime, especially if it is on a regular basis (habit). You are getting jetlagged. Try reading before going to bed. If you are reading a tablet, just turn the brightness to as dim as you can. Works for me. I also heard on NPR News recently that some people are just natural night owls. Everything I described above has been my experience. :) And to the contrary, many people are just natural \"larks\" and get up early (freaks!). But it turns out that your sleeping patterns generally change depending on your age. You may have been hearing lately about them considering turning the arrival time of high schools a little later in the day to 9 or even 10, to adjust to teenage sleep patterns.",
"[here is an article]( URL_0 ) referencing a study about sleep deprivation and young people. So, as someone mentioned above, you have hormones that help regulate your sleep cycle. These hormones can be offset by things like: * too much artificial light in the evening * caffeine * dehydration A person going through what you described could also suffer from things like depression (lethargy, general tiredness) and anxiety (increased heart rate and anxious thoughts keep you up at night) but that would be for a professional to diagnose. Edit: for me, it's always my phone that screws me up. I don't look at screens after 11pm and almost always pass out within an hour afterward."
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78gpvk | Why does freshly brewed coffee taste so differently after it cools down and you heat it back up? | Chemistry | explainlikeimfive | {
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"Some compounds in the coffee oxidize when they come in contact with air, which makes them bitter. That's also why you should keep ground coffee in an airtight container."
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78gus7 | Why do our mouths get dry after eating salty food like pretzels? | Chemistry | explainlikeimfive | {
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"Salt causes water to \"leave\" a substance trough a process called osmosis. When you eat salty food, osmosis happens in your mouth, gathering saliva from your mucous membrane. Edit: spelling",
"Salt causes dehydration.its just a property of the substance. This is why you can use it to preserve foods (microorganisms have trouble surviving in environments that are heavily salted, because salt literlaly forces water out of living cells) and why you arent supposed to drink sea water."
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78h33w | What is bounded rationality as it relates to behavioral economics? | Mathematics | explainlikeimfive | {
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"Let's say that I'm trying to get to a bar downtown to meet my friends. I can get in my car and drive down there, call a cab, ping an uber, or just hop on my bike. I'm a rational person, so I weigh my options. I know that parking isn't great, so I rule out driving my own car. Cabs aren't common in my neighborhood, so I rule that out. I think about getting an uber, but it's rush hour so I have a feeling that traffic will be slow. I decide to ride my bike. If we pause here, we can say that I made a decision rationally. But let's say that I get on my bike and an unexpected rainstorm gets me wet. To make matters worse, the roads are clear so my expectations of traffic weren't in keeping with the reality of the situation. I finally arrive at the bar, cold, wet, and late, only to see that there were spots open in the parking lot. Clearly my decision wasn't the optimal decision, but it was a rational decision. Bounded rationality is the idea that human beings make a lot of economic decisions rationally, but they are constrained (or bounded) by incomplete information, time limitations, or other realities that may not allow them to make the ideal decision.",
"\"Rationality\" in economics is a set of [axioms about rational actors:]( URL_0 ) * Preferences are *complete:* For *any possible* set of options, a rational actor can sort them in order of preference. That is, they *know* that they prefer Pepsi to Coke, but they also know that they prefer Ramune to Jaffa and they are indifferent between Sprite and Sierra Mist (Sprite and Sierra Mist are equal.) * Preferences are *transitive:* If A is preferred to B, and B is preferred to C, then A is preferred to C. That is, a rational actor who prefers Pepsi to Coke, and prefers Coke to Mountain Dew, they will prefer Pepsi to Mountain Dew. * Preferences are a *continuous function:* If A is preferred or equal to B, and B is preferred or equal to C, there is a combination of the probability of receiving either A or C that is equal to receiving B. That is, if you prefer (or are indifferent between) Coke to Pepsi, and prefer (or are indifferent between) Pepsi and Mountain Dew, then if someone offers you a mystery pop that's, say, a 75% chance of being Coke and a 25% chance of being Mountain Dew, you are indifferent between that Schroedinger's pop and Pepsi. * Preferences are *independant:* If you prefer A to B, then you will prefer A + C to B + C regardless of how you feel about C. That is, if you prefer dogs to cats, you will prefer a dog while living in an apartment to a cat while living in an apartment. Now, on to bounded rationalty: We know the axioms of rationality don't accurately describe people, they *cannot* describe people for several reasons: Completeness is impossible. The simple fact is that completeness would require us to compute our preference for *every possible combination of everything* before making any decision, and that would take more computing power than is even theoretically available, much less what we actually have in our heads. So, we model economic actors under certain limiting cases: What happens when actors have incomplete information? That is, what if they don't know how much utility they will gain from a certain thing, such as when buying a used car where they don't know if it is a good car or a lemon? Also, what happens if agents use a heuristic instead of actually calculating the exact expected utility of something? That is, instead of asking \"how much utility will I expect to get from action A compared to actions B, C, D, and E\" they instead ask \"Was A worth it in a similar situation?\" As for behavioral economics, honestly I haven't read up on the formal theories of behavioral econ, pretty much all I know is from popular literature like *Nudge.* Most of the places I've seen bounded rationality used are in neoclassical models, to improve them and get them to better reflect real world behavior. Most of what I see in behavioral econ is a focus on how people actually make decisions, that is, looking for things like biases and consistent misperceptions, and then trying to build models up based on that."
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78h49w | How is Autism treated? | Biology | explainlikeimfive | {
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"You don't treat autism. You learn to live and function around it. It's not something that can be corrected. Less severe forms on the spectrum are easier to deal with than the forms that are more severe.",
"1. Autism is not a single disease. It is a name for a \"spectrum\" of disorders that present with a diverse but recognizably similar set of symptoms. But it's not what causes most of them, let alone if they have similar causes. 2. Most disorders located on the \"autism spectrum\" aren't \"treated\" nearly so much as \"managed\". There isn't any real \"treatment\" for neurodevelopmental disorders the way there is for, say, bacterial infections, or even cancer. When the body doesn't develop the way it's supposed to, there's often not a lot that can be done about it beyond trying to mitigate the symptoms. 3. Autism spectrum disorders are mostly managed with a combination of special education and behavioral/occupational therapy. The goal is less making the symptoms go away, and more helping the person live with and take charge of those symptoms. 4. In this context, \"ABA\" probably refers to \"applied behavior analysis\". There's a detailed [Wikipedia article]( URL_0 ) on the subject. TL;DR: it's a clinical way of trying to understand *what* a person is doing (it's not always as obvious as it sounds!), *why* they're doing it, and *how* to get them to replace a specific undesirable behavior with a desirable one."
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78harq | Why are voices so distinct and recognizable? | Biology | explainlikeimfive | {
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"Human's voices depend on a lot of things, but what most people don't know is that a lot of it has to do with how the face is shaped. Air flows differently through different shaped mouths and tongues. Case in point, Freddy Mercury never wanted to get his teeth fixed because he was afraid it could affect his singing voice. Also that is why people who are siblings or more specifically twins tend to sound alike, because they have similar facial features. As to why voices are so recognizable, its a survival trait. We are hardwired to remember the sounds our mother and father make so we can find them and discern them if we can't see or are separated. I am sure there are other reasons, that's just what I learned."
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78hc0u | Why do our eyes jolt around when looking around, instead of smooth transitions? | Biology | explainlikeimfive | {
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"Your brain actually conveniently \"forgets\" the inbetween. You saw what was there, but your mind didn't \"play\" the transition. This is because when your eye darts around, there is a fast blur. Because seeing blurs all the time is annoying junk information to the brain, you end up seeing and remembering only the clear views from before and after your eye started moving. However the stuff you \"didn't see\" wasn't lost. You can remember \"seeing\" objects your eye passed over, even though your mind didn't show you exactly what it was in that instant blur. You can notice things you never explicitly looked at."
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78hl1u | How do cryptocurrencies become regulated? | I've recently read news about China blocking ICOs from happening. I've also read about Gab and how they are the world's first Reg A+ ICO. Is this a good thing or a bad thing? Does this defeat the purpose of being decentralized? | Technology | explainlikeimfive | {
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"China is a special case. There is no Internet there, only a China-subset Internet. When they block ICOs, they are saying companies inside their Great Firewall can't participate in them. If there are regulated and non-regulated ICOs, then users can vote which they prefer, by which they buy. It's still decentralized, even if some players in some coin offerings are working under central regulators.",
"You can't regulate a cryptocurrency. You can regulate an exchange however, requiring everyone to show ID and provide documentation to prove income. You can regulate or block an official investment fund into a cryptocurrency too. They can regulate the fiat currency being used to buy crypto. Compare to gold. You can regulate the shops that buy and sell gold, or regulate people on wall street that invest huge amounts of money into gold. However you can't regulate gold in the fact of going door to door and making sure only a set number of gold exists in the world. And in the case of bitcoin, since bitcoin is protected by a private number, you couldn't force it away from someone's hands without going through the person first. Even in a crazy situation where the bitcoin rules changed and the government was in charge, people would easily move to a separate fork of bitcoin, or even move to litecoin, peercoin, or a brand new coin.",
"Crypt-currencies are very hard to regulate, by design, because there isn't any single entity to point guns at. You have to point guns at everyone. Anything that can't be controlled by pointing a gun at someone can't be regulated.",
"The gov says what any business can and cannot do. The risk of doing something that gov says you can't is at best a fine. You can go to jail or worse. If China says you can't trade cryptos, then you risk fine, jail or worse for doing it. Business owners won't risk it. Private people might...until someone gets caught and it ends up in papers....or don't end up in papers and you never hear from them again. China gov much less affected by local population vote pressure. If gov says marijuana possession with intent to sell is death sentence, no amount of public outcry changes it."
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78huh6 | Why shouldn't you put hot water from a tap into your kettle to boil? | Other | explainlikeimfive | {
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"Hot water heaters hold water for long periods of time, and as such they often have buildup of various sediments and other contaminants that you really don't want to be ingesting on a regular basis. Also, it fouls the flavor of the water. Especially if you have scale issues. Take two cups. Fill one with hot water, fill another with cold. Put them both in the fridge. Once the hot water is cold, taste both cups. You'll see that the taste of the hot water is not nearly as good as the cold.",
"Unless you've got a fancy newer home, your hot water probably comes from a tank-style water heater. Those tanks aren't the cleanest things in the world (it's not like simple piping that has water flowing through it more constantly), hot water dissolves contaminants more readily than cold water, and in general it tastes funny. In some cases it could be unsafe, but by and large it just tastes worse.",
"I do it all the time. Never bothered me. I have a new water heater. I will agree fresh cold water is theoretically cleaner. But I can state that my city has very good tap water which comes from lake water which is thus rainwater, not from wells, or from polluted streams which cannot possibly be cleaned as clean as when it started as rainwater from a forest."
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78hwr4 | How do certain celebrities grow old and still function and look (reasonably) good after so many years of extreme drug abuse? I.e Mick Jagger, Bowie, Ozzy. | Biology | explainlikeimfive | {
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"A lot of makeup, professionally applied and/or cosmetic surgery. In some cases, genes help. But for the most part, they're not naturally as good looking as they appear in public."
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78i3a3 | Why does someone get nauseous in the car as a passenger, but not as a driver? | Biology | explainlikeimfive | {
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"My understanding is nausea is caused by the disconnect between eyes and inner ear. Your ear feels the movement, but if your eyes are, for example, reading then they are not reporting the movement. This causes nausea in more sensitive people. Looking out the window, like the driver is, keeps the two senses in synch.",
"Nausea basically is the body believing it has been poisoned. It wants to make you vomit, to get rid of as much of the poison as possible. A typical symptom of poison is your moovement (as your eyes see it) not correlating enough with what your brain anticipates. As a driver you anticipate correctly, as you are in direct control. As a passenger you get some \"blurred\" vision compared to what you would expect to happen (because the driver is steering). This leads your body to the (false) believe of being poisoned and thus making you nauseous."
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78i75p | Why do our eyes adjust to bright light quickly but take a while to adjust to the dark? | Biology | explainlikeimfive | {
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"Your cones (the vision receptors designed for bright light and color sensitivity) can fully adjust in only a few minutes. Your rods (the dark-adapted receptors) take much longer, 30+ minutes for just 80% adaptation. Your cones play some part in looking in the dark, so it doesn't take 30 minutes to start adjusting to the dark, but full dark adaptation can take hours.",
"In addition to the biological/cellular reasons, your eyes can be damaged by too much light but not by too much dark. So in terms of evolution, that's probably why human eyes adjust more quickly to the light."
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78iaj3 | Why can you aim with scopes? | I don´t get why you can shoot where you aim, I mean the scope is 2-3 cm over the barrel and if you see something in the crosshairs of the scope, the bullet should hit 2-3 cm under the aimed target, shouldn´t it? | Physics | explainlikeimfive | {
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"It's worse than that. While the bullet is flying, which lasts for maybe two tenths of a second, it's also falling. The longer it has to travel, the more it falls. That's why scopes are adjusted for a particular distance. Relative to the barrel, the scope actually points a little bit downward, so that the line-of-sight through the scope matches the bullet's path at the chosen distance. Most scopes can be fine-tuned in the field to match different distances.",
"[Here's an exaggerated diagram of how rifles actually work]( URL_0 ): note that in most cases, you shoot up, and then let gravity take your bullet in an arc. The scope (or other optic) will then typically be accurate at 2 distances, the intersection of the line of the scope's visual range, and the ballistic arc of the bullet both ascending and descending.",
"> I don´t get why you can shoot where you aim, I mean the scope is 2-3 cm over the barrel and if you see something in the crosshairs of the scope, Because your scope is not parallel with your gun. Assuming you were shooting from a very close range, you would adjust your scope to point down slightly to compensate for those few cm. However, gravity exists. Due to this, your scope also takes that into account so it likely is not pointed slightly down, but up. tldr ; scopes are \"zeroed in\" to compensate for this (and distance)",
"Bullets don't travel in straight lines. Think about throwing a ball. If you're throwing a ball to a friend 30 yards away, you don't throw the ball in a straight line directly at them, you throw upwards at an angle so the ball will arc towards them. It's the same with bullets. They don't ignore gravity just because they're moving really fast. If you hold a rifle barrel perfectly level, and fire a shot...that bullet will drop towards the floor at the same speed as a bullet you just drop from your hand... they just *seem* to go straight because a bullet travelling at 700mph plus will make it a long way before it hits the ground So, with a rifle scope, you have to 'zero' it for the distance you're shooting. In very simple terms, you shoot a group at a target, see where the shots land, then adjust your scope to match. If my shots land 2\" low, I adjust my scope to to 'point' 2 inches lower."
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78ibuq | If food makes it into your lungs accidentally, how does the body deal with it if your lungs can’t digest it? | Biology | explainlikeimfive | {
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"Usually not good things. First off, you'll start coughing. That's your reflexes trying to get whatever it is out of your lungs. If that doesn't work, your lungs will have an inflammatory response and start producing more mucus. Just to be clear, your lungs can't digest things at all. If a large bit of food gets in there and you can't cough it out, it's going to stay there. Since your lungs are dark and warm, it's a great place for bacteria to grow. You can get a nasty infection and might even get pneumonia. Do you know how much rice you inhaled? You might want to see a doctor. URL_0",
"Pneumonia. My grandmother aspirated her food like that, that's what happens if you can't get it out."
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78ieln | What makes the molecules of certain objects passive to other molecules of other objects? | Chemistry | explainlikeimfive | {
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"text": [
"Collision theory. In order for molecules to react: 1. They must be collide. Basically they must bang into each other 2. They must collide with the correct geometry. Think of it like if you had to pieces of a jigsaw puzzle, and basically they can't join if they don't have the correct direction or orientation. 3. They must have energy greater or equal to the activation energy. Basically there's an energy barrier and if they collide, and with the correct geometry, nothing will happen if they don't have enough energy to 'react' Also in your case, many molecules don't react with each other because they are already stable. Basically they don't need to react because they are happy how they are. One of the fundamental ideas behind reactions between molecules is they try to react and do all kinds of crazy shit to be more stable than they were before. Another reason is the phase of your molecules. A good example is an acid and a metal. If you have acid in the form of a solution and place a piece of metal in it, most likely it will start corroding the metal. However, if the acid was dry, and there was a vaccuum such that no water vapour was present, there will be no reaction. It's one of the cool things about acid/base reactions is that water is needed."
],
"score": [
7
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
78iisw | Why do baseballs go further in the heat than in the cold? | Physics | explainlikeimfive | {
"a_id": [
"dou2zj3"
],
"text": [
"When a gas is heated, it expands which lowers it's density. Since the density is lower, there are less particles for the baseball to collide with, so it goes further when the air is warm. Also, something funny and slightly related is that baseballs also travel further in humid weather because the water particles in the air are lighter than some of the molecules they displace, so for a constant temperature and volume the humid air is lighter and collisions don't slow the baseball as much."
],
"score": [
13
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
78ij55 | Are animals, or I guess anything that isn’t human, aware of the concept of time? Obviously they are aware of things like seasons and things like that, but I’m talking physical time. | Other | explainlikeimfive | {
"a_id": [
"dou436o"
],
"text": [
"It depends on what you understand by time. Time is a human concept, and it refers to localizing yourself inside this causal chain that makes up our liniar existence. You can \"tell time\" because humans have defined it based on certain things, and you can use this common definition to express ideas or locate yourself in that flow. However, this definition is arbitrary. We have defined the units of measurement, their names, the relationships between them, and so on. Of course, animals cannot sense or perceive these notions in any way since they don't exist unless someone teaches them to you. However, time is based on the fact that we as humans have observed certain cyclic behaviour in our planet. From the day-night cycle to the seasons, we notice that time repeats itself at a certain interval. Animals can sort of pick up on that, but they perceive it in two major ways: 1. As a natural instinct, that is either in their genetic memory or taught by their parents. This teaches animals how to survive when winter comes or when to sleep. 2. As a reaction to changes in the world around them. This is based on their needs, and of course, when they notice it gets dark, they go to somewhere where their impaired senses don't matter as much, or when it gets cold, they go somewhere that it's less cold. I guess it all depends on what you're talking about, more precisely."
],
"score": [
12
],
"text_urls": [
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} | [
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|
78iouj | Is there a benefit to humans growing so slowly compared to other animals? | Biology | explainlikeimfive | {
"a_id": [
"dou57ub",
"douf86s"
],
"text": [
"There is no benefit to us growing so slowly. Rather us growing so slowly is a side-effect of other traits (mainly walking upright and our big smart brains) that are a benefit and we selected for during our evolution.",
"Unlike most animals, human brains end up consuming up to 40% of the body's energy during childhood. So the brain is growing much faster, at the expense of the rest of the body. However, it is important to note that when compared to life expectancy, most mammals tend to reach sexual maturity and adulthood at very similar rates."
],
"score": [
7,
3
],
"text_urls": [
[],
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} | [
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"url"
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