Datasets:

eli5_category

like 10

{ "a_id": [ "h2na67x" ], "text": [ "It used to described the smallest size of the structures etched into the silicon chip. However, these days it's rather arbitrary, many structures on modern chips are smaller than the given number while others are a lot bigger. 5 nm is smaller than 14 nm and thus the production process is more advanced. How much smaller? No idea. Probably not by 9 nm. Modern chips are slowly reaching the limit of what's possible because some structures only consist of a few thousand atoms and quantum physics make them behave weirdly." ], "score": [ 7 ], "text_urls": [ [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2nf6vh", "h2p98z6", "h2oc8sj", "h2ok42n", "h2onj8a", "h2p1sxl", "h2oqd2h", "h2ohj96", "h2on6p0", "h2oo94d", "h2p949w", "h2p5qtc", "h2q1q4h", "h2pqez8", "h2oksoa", "h2ozcz6", "h2oypxf", "h2ok7n5" ], "text": [ "What happens is the rough inside later of the igloo melts a little bit at first but the super cold ice behind it which is being kept cold by the outside temperatures freezes it again in to a smooth crust. Because there's now less surface area the warm inside air is less effective at melting the surrounding ice. So basically it's a constant battle between the fire inside warming up the air and the ice and cold air keeping the structure frozen, and the achieve a balance at some point.", "I'm an Inuk from Nunavut and I have experience with this! In the colder seasons of winter often between November to April are the peak freezing temperatures, the snow packs harder from winds and cold making snow easier to pack and build into shape, forming a stronger integrity of an igloo (proper name is ᐃᒡᓗᕕᒐᖅ \"Igluvigaq\" ) with the cold atmosphere keeps the exterior of the Igluvigaq frozen, the interior warms by the flames of stone lamp called ᖁᓪᓕᖅ \"qulliq\" melts a thin wall making film of ice. The ice is kept frozen by the outside, making the Igluvigaq insulated and keeping the Igluvigaq nice and toasty! Igluvigaq are often used in temporary shelter when going out to hunt and harvest away from family camps.", "Snow with an ice layer over it is very insulative. That keeps the heat inside and the cold out. It also keeps the heat out of the actual snow and the ice sort of keeps itself cool. It is the same reason that snow that has a crust of ice takes so long to melt even if it is way above freezing.", "I learned how hard it is to melt snow/ice with fire in an interesting way. My boss told me to we had a “parade” of higher ups coming through. There was a bunch of dirty snow in the parking lot. I went to Home Depot and rented the biggest kerosene heater I could. Had guys pack it up high and pointed it right at the base. Maybe an hour later very little progress. One of the guys who reported up through me walked by, called me a dumb fuck and said that’s going to take forever. It was 60 degrees out and he grabbed 2 guys and they broke it up and threw it in a thin layer over the parking lot. Took like 2 hours to melt on its own after that. It would have taken us a day to melt it all. Anyway, getting schooled by a technician was fun. Little did he know I just wanted to play with a kerosene heater. But, he did get to call me dumb which was a positive for him and taught me a lesson on how many BTU’s it takes to phase change ice to water.", "URL_0 . To avoid melting the ice, people must keep the ice below its melting temperature. That means that they can’t add heat to ice indefinitely. But while a central fire will always deliver some heat to the ice of the igloo, the ice of the igloo will also tend to lose heat to colder air outside. As long as the ice loses heat at least as fast as the fire delivers heat to it, the ice won’t become any warmer and it won’t melt. Water has a lot of latent heat. This means that it requires a lot of energy to transform water from ice to liquid, even though the temperature stays at 0°C. Furthermore, water has a high specific heat capacity, which means it takes a lot of energy to change the temperature at all. And finally, even though the air inside is maybe ~10°C, the outside might be waaay below 0°C, and might might be windy, causing the equilibrium temperature of the ice to be well below 0.", "An important note is that the goal of warming the inside of the igloo is NOT to keep the inside a temperature that you would be comfortable in your home. It is to make it more comfortable in clothes and blankets. The structure does melt if the internal temperatures get too high. As others have said, you want to find an equilibrium so that the melting is not happening faster than refreezing. If you want the structure to last more than a few days, the internal temperature needs to be fairly low, say 40s or perhaps up to 50s. This is a welcomed respite from negative temperatures in the arctic. Snow melt, humidity from your body, and breath will freeze into the cracks, helping to seal the structure and block wind and the elements from infiltrating. However, ice is a much worse insulator than the packed snow initially used to create the igloo, so you don't want the walls to too thick with ice. The ice also helps trap moisture inside, thus increasing the relative humidity inside of the igloo. Super cold air is very dry, and can make it painful to even breathe. Humid air also holds heat better than dry, so a small heat source can provide a better warming effect when the humidity is slightly higher.", "Not an igloo expert, but am firefighter trainee. Fire science is... wild. The stuff you learn in high school chemistry doesn’t hold a candle(eyyy) to the real thing. Heat wants to rise and so does fire. You know how they always say close doors and windows to contain a structure fire, and how modern buildings have actual fire doors? Basically what this does is contain a fire until help arrives. It’s not going to put it out. What firefighters do in a fully involved fire is the exact opposite. They vent the roof directly above the hottest part of the blaze. This causes both smoke and heat to escape vertically so that a fire attack team can enter from the side and extinguish the fire without being melted. Turnout gear and water vapor alone have their limits. In addition, water doesn’t magically extinguish fire, as you can see from oil fires burning on water. Water only cools the fire’s fuel below its ignition point and thus puts it out. So I’d imagine with the igloo scenario, enough heat escapes vertically that the interior is warmed without melting the ice, and the cooling effect of the outside air on the ice keeps it in a solid state. I’m sure many igloos have melted from too much fire and too small a chimney.", "Igloos often have a small hole in the side and one on top. The side hole allows fresh air while the top hole allows CO and smoke to leave. Much of the heat also leaves through that hole.", "Same reason you can sit a few feet from a fire and not burn. The heat just doesn’t get too intense too far from the flame itself. Plus it’s very very cold outside the igloo", "They say if you ever get stuck in a car in the middle of winter, a tealight candle on the dashboard can provide enough heat to get you through the night.", "It is a lot harder to melt ice than most people realize. It's not just heating ice from 0C to 1C; you have to add enough heat to cause a state change, which doesn't even change the temperature. You are basically melting 0C ice into 0C water. Which also means that the melted ice doesn't help you melt more ice. [Here is a documentary that explains it better than I could.]( URL_0 )", "What about the smoke from the fire? Thats the thing i always wonder about...", "Conduction vs convection. The convective heat put off by the fire just isn’t enough to overcome the amount of heat that the thick walls of an igloo can absorb through conduction. It would take an immense amount of BTUs to melt the walls of an igloo. Ever seen the video of the guy trying to melt the snow on his driveway with a flamethrower? It didn’t work very well…. It takes only a small amount of convective heat and few BTUs to warm the air inside the igloo. Think about breathing on the palm of your hand. The surface of your hand gets warm for about 3 seconds. But you could never breathe on the palm of your hand enough to make the back of your hand warm. Now imaging the back of your hand is -10 degrees. Your hand is going to be frozen regardless of a little warm air hitting one side of it.", "I have a follow up question about this: How come mountaineers never seem to build igloos (ᐃᒡᓗᕕᒐᖅ as /u/IpodAndMp3 stated) when they get in trouble on a mountain? For instance, in the 1996 Everest disaster, where 12 people died, not one had tried to shelter in the snow (as far as I know). In addition to that, I have never hear of *any* mountaineer trying to shelter in an igloo to combat exposure - which seems obvious for a number of reasons: snow is abundant and a professional camp stove is very light, compact, and can be used to make water from ice - I would assume that would be an essential thing on the way to the summit. Now, I realize the Everest disaster has many, many, other factors: HACE, massive storm / wind, well above the death zone, lack of O2, fatigue (especially), etc. I am not trying to suggest I know shit about anything in this regard - it's the one example I can think of. I am legit curious and as, like I said, I haven't heard of this type of shelter in any / many exposure incidents. My best guess is that snow on the tips of mountains are not \"sticky\" enough for this sort of endeavor? Anyways, enlighten me.", "Not all ice is created equal. Some ice is only 31 degrees Fahrenheit and easier to melt. Other ice can be 10 below 0 Fahrenheit. So an igloo which can sustain a fire inside will be closer to the latter example. The inner most layer may melt a bit but will refreeze immediately since the ice behind it is so cold.", "It looks like your question was mostly answered. I would add that another good example is that ice fisherman who are out on the ice for the day (not in a fishing shanty) sometimes start a fire on the ice for warming up and cooking. The ice melts a little and then a layer of cold water battles with the fire on one side and the ice on the other (very similar to the layer inside the igloo). Even after a full day of fire, it will only melt a few inches into the ice.", "I also always wondered how they are ventilated?", "Because blankets are hung up inside the igloo. They help to insulate people, and they also help to insulate the ice from warmth. Any ice that does melt goes down into a channel that goes over by the door where it's colder where it freezes. Basically, there's a blanket fort inside the igloo and that's what people really live in." ], "score": [ 8928, 2808, 307, 156, 103, 52, 33, 26, 12, 11, 11, 6, 5, 5, 4, 4, 3, 3 ], "text_urls": [ [], [], [], [], [ "https://howeverythingworks.org/1997/01/10/question-730/#:~:text=But%20while%20a%20central%20fire,and%20it%20won't%20melt" ], [], [], [], [], [], [ "https://www.youtube.com/watch?v=uKBtFUufqL0" ], [], [], [], [], [], [], [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2nhcul" ], "text": [ "With respect to stocks, options contracts are essentially bets that the underlying stock price will (or will not, if writing them) move at least a certain amount in a single direction by a certain expiration date." ], "score": [ 3 ], "text_urls": [ [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2njeom" ], "text": [ "Generally speaking, good journalists have lots of ways to get criminals to speak with them. Many people want to share their stories. They may think they can use the publicity to their advantage. They may have egos that can be exploited. The key is that journalists aren't going to arrest these people, so they can sometimes get access that law enforcement can't." ], "score": [ 5 ], "text_urls": [ [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2nk9o2", "h2nnnp1", "h2npq3f", "h2nk7cp", "h2nmxn1", "h2nyta0" ], "text": [ "\"Significance\" in this context doesn't mean \"this is true\", it means \"The chance this is true is pretty damn high\". Generally speaking, the stronger the correlation, the more true it's likely to be. The P value is essentially a value of how likely it is that the results you got were just a fluke - that there's no pattern at all and the data just happened to come out looking like there was. The tests that determine P value just look at the data in the abstract and the amount it deviates. The lower the deviation, the lower the P value, because it's very unusual for random chance to produce results with very low deviation. It could still happen, which is why the P value isn't 0, all you're doing is saying \"The chance random chance produced *these* results is sufficiently low that we can decide the correlation is significant and therefore reproducible\". Also, there are cases where a P value of 0.05 is still too high to be confident the correlation is actually there. In some cases, the results won't be considered significant until the P value is 0.01, or even lower.", "statistical test cannot \"prove\" significance. In fact, you cannot prove statistical significance at all, you can only measure it. There are many techniques to measure it, but then you usually get a couple of numbers. Usually, most important number is the p-value, (other numbers include size effects). p-value stands for probability. It measures the probability that nothing happened, but you got good results anyway due to luck. For example. Let's say I claim to be a psychic who could control chaos magic like Wanda and determine the result of a coin toss. How many heads in a row is enough to convince you that I am a psychic? If I throw 2 heads in a row, you might just call me lucky. If I throw 5 heads in a row, you might think that I might be up to something. If I throw like 20 heads in a row, I will definitely get your interest. Either I got an excellent throwing techniques, or there are tricks in the coin, or I'm a real psychic, but you would be pretty sure it is not up to chance. So maybe for you the limit is somewhere between 5 and 20 coin tosses. If you do the statistical test, the P-value of 5-head is 0.03125, while for 20-head is 9.5e-7. Now, the same with biology, let's say testing if a medicine is working. How do we know if a medicine is working, or is just up to luck? ************************************* Well, you wanna find out the p-value. to do that, you use one of the many statistical tests. These are tools that people can misuse and abuse. In fact, it is kinda hard to get it right. And then you get a p-value. Different fields have different standard. It seems that you are familiar with p < 0.05, which is 1 in 20 chance that it is luck. Other fields use p < 5sigmas, which translates to 1 in a million chance. URL_0", "Short eli5 answer: P Value is \"Assuming our hypothesis is wrong, what are the odds that we got this result by chance?\" It's not proving or disproving anything, including a relationship between two variables. All it's doing is saying that assuming our hypothesis is wrong (aka null hypothesis/status quo is 'true'), you are (P Value*100) percent likely to see the result we got.", "The basic idea is that when doing an experiment, you get a certain value with a certain probability, which can be described by a probability function. Most often, it's assumed that your probability function is the normal probability distribution, aka the bell curve. Then you fit 2 such curves to each of your observation sequences (e.g. patients that received a drug, and those who received a placebo), and look at how much these bell curves overlap. The less the overlap, the lower the probability that it's just different by random chance.", "When we find a relation with a small p-value we are essentially saying there is a small chance that the relation is due to random chance. This then allows us to accept a hypothesis as a certain level of confidence. When using p-values and other statistical methods you are looking to either accept or reject a hypothesis that you have created. Frequently, we use the null and alternative hypothesizes for simplicity. When creating a testable hypothesis it needs to pass the sniff test. Historically, the butter production in various countries has had a an significant relation to the returns of the S & P 500. This doesn't mean that the relation is neccesarily true though. With the ridiculous number of possible relations in our data rich world there will be significant relations between variables that make no sense. The probability of getting 10 heads in a row is incredible small but in a set of 100,000 flips its actually fairly likely. The way to get around this is either using common sense in data and relation selection or to find significant relations in comparable data. The correlation between worldwide non-commercial space launches and Sociology doctorates per year is high but does it really mean anything? Maybe if space launches correlate with science funding and total doctorates also increase with global science funding? Maybe the US has the majority of space launches and so it makes more sense. A high probability does not imply truth. URL_0", "What you're getting at is that \"significance\" doesn't really mean \"significance.\" A better term for \"statistical significance\" is \"statistical discernibility.\" You measure some X and Y 100 times and find a correlation of 0.42 with some standard error. Then you ask, \"Okay, if the true correlation between X and Y were zero, how hard would it be to draw a sample of 100 with a sample correlation of 0.42 or more extreme?\" The answer to that is your p-value. If the p-value is low, you're saying \"We can't ever know the exact true correlation, but we can be very confident that it isn't zero.\" You're saying your result can be discerned or distinguished from zero. But, statistical significance doesn't mean that it substantively matters. That's a matter for effect size and the confidence interval around it. Suppose you're researching the effects of eating blueberries on human longevity, and find a statistically discernible effect. If that effect is \"You would have to eat the entire mass of the earth in blueberries every year to extend your life by one month,\" it doesn't really matter even if the p-value is 0.0000000001. Statistical significance also doesn't mean causality; the usual examples here are Tyler Vigen's spurious correlations. X and Y can go together because: * X causes Y * Y causes X * They both cause each other simultaneously * There's some Z that causes X and Y * Other stuff I'm forgetting * For literally no reason at all Figuring out causality is, mostly, a research design question and not a statistics question. There are circumstances where causality is relatively straightforward statistically, but you have to be able to perform true experiments or have to luck into the right kind of data being available. When you can't do a true experiment and you don't have that lucky kind of data, what you mostly do is ask \"What would the world look like if I were right? What would it look like if I were wrong?\" If you're right, more X goes with more Y, and more A goes with less B, and so on. What you'd like to do here is have a whole set of things to look at, some of which are weird or surprising. You can see a lot of this with early covid or other epidemiological study -- if it's spread by air, then we should see these relationships between variables, but if it's spread by droplets, we should see other relationships that we wouldn't see if it were by air, and if it's spread by contaminated water we should see yet other relationships." ], "score": [ 52, 35, 7, 3, 3, 3 ], "text_urls": [ [], [ "https://news.mit.edu/2012/explained-sigma-0209" ], [], [], [ "https://blog.psyquation.com/es/correlation-with-a-twist/" ], [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2nlb4b", "h2nm1zp", "h2nlc9x" ], "text": [ "The application is designed for it. It is able to save its work and resume from that save. There's not really any trick to this, just good software design.", "If you have anything that runs for at least days, you want to design your program to have \"saves\" or checkpoints, etc. For an eli5 example, let's say you are searching for really big prime via brute force, and sequentially. You could simply memorize the last number you check. And then continue the search from there.", "For a program that takes years to complete you write the program in such a way that it's constantly writing output and you can pause and save the state of it at any time." ], "score": [ 22, 16, 5 ], "text_urls": [ [], [], [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2nl9a5", "h2nnikm" ], "text": [ "Cavemen desperately needed to know what beige mushrooms were tasty and which slightly beigeier ones were deadly poison. Those that failed this test wouldn’t pass on their genes. The ability to tune a guitar by ear is a lot less useful when all music is rock-smacking that’s unlikely to help you reproduce, and so such high hearing granularity was never an evolutionary priority.", "Kids are not born with the ability to recognize colors. This is something which we learn as we grow older. You might have had color charts in kindergarden where you had to name all the colors of the rainbow and such. But you probably did not have to name all the notes on the scale just by listening to them. As a matter of fact you do not have to go that far back in time when people did not learn about so many colors as we do today. In the same way that someone might only be able to say if a pitch is deep or high people witohut any training in recognizing colors might only be able to say if a color is dark or light." ], "score": [ 6, 5 ], "text_urls": [ [], [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2nvkrq", "h2o7j1y", "h2nvu5f", "h2nuqzy", "h2ohvo1" ], "text": [ "Ice cores. Where you drill a big hole in the ice and pull out samples. When Ice freezes, it traps tons of little air bubbles in it. These little air bubbles have the same composition of the overall atmosphere when that sections of ice froze. So, if you were to go somewhere like Antarctica, and drill down hundreds of feet, you would get to ice that formed a long long time ago, thousands and even hundreds of thousands of years for the deepest cores. You now have ice that froze a long time ago, and trapped a sample of the atmosphere from that time in it. You have a sample literally frozen in time. You can then take that to a lab and do an analysis of how much CO2, Methane, O2, and other gasses are present and compare that to levels we see today and from other younger or older ice cores. Edit: as for exactly how accurate they are I cannot say what the margin of error is. Each scientific study should report their own margin of error. But when you take an overall view over hundreds of studies and thousands of samples taken, this data is accurate enough and the best option we have to make the models and predictions we need.", "Omg It happened My area of specialty!!! I see lots of ice cores mentioned here. Definitely a method deemed reliable. There are other methods, such as tree cores! Uses very similar measurements and all that. It has to do with molecular processes and enzymatic favoring of different isotopes (C, O, others). Those isotopic signatures remain in the molecular structure and can be quantified, along with other environmental factors, to build a fairly accurate representation of a “moment (grow season) in time”", "What I want you to do is imagine you're a giraffe. Now that you've done that completely irrelevant thing, think about snow. Specifically, think about what happens when you walk on snow - you sink. This is because snow is a bunch of tiny ice crystals layered gently on top of each other with lots of air between them. When you stand on it, the air gets pushed out and the ice crystals get compacted. The reason this happens is simply because you are heavy - any other heavy thing put on the snow will also cause this to happen, including more snow. When you put a bunch of snow on top of snow, the snow at the bottom gets compressed. Some of the air gets forced out of it, and the ice fuses into one big sheet of ice. Some air gets trapped inside the sheet when this happens. In some places, like Antarctica, it snows pretty often, so you keep getting new layers of snow deposited on top of older layers, resulting in the snow at the bottom becoming compressed. This process happens regularly over hundreds of years, creating a thick layer of ice called a glacier or ice sheet. The ice at the bottom of this sheet is older than the ice at the top because of the way snow always falls down from the sky, and not up from under the ground. You could take a segment out of this ice sheet, a long thin one from top to bottom, and if you did the ice at the top would be very recent and the ice at the bottom very old. All of this ice has air trapped in it, which was trapped when the ice turned from snow to ice, so it's essentially a time capsule of what the atmosphere was like when that ice was formed. If you open up one of those air bubbles, you can measure the CO2 in it, and you can estimate the age of the ice based on various things like how much snow gets deposited in a given length of time.", "One method is to analyze ice. They drill deep holes in very thick glaciers. So the ice from down below is very old, even thousand of years and hast small bubbles of gas included. This gas is very old air which can then be analyzed. Almost a million years ago, the ratio of heavy and light isotopes of oxygen (O 16/ O 18, H / D or hydrogen to deuterium) provides us with information about temperature. It is crucial that in the process of evaporation of the ocean water, i.e. the phase transition from liquid to gaseous, the isotopes of the constituents of the molecule water (H2O), i.e. O 18 or D compared to the \"normal\" atoms O 16 or H, depending on the the temperature of the ocean water changes into the gaseous phase at different speeds. Isotope physicists speak of temperature-dependent defraction", "It depends on the age of the time frame under discussion. Ice cores preserve bubbles of air that existed at the time of capture, so are good witnesses of air composition, but ice has a limited age (rare to get ice more than a couple hundred thousand years old although there are a few locations where older ice has been recovered). Precision is relatively high as far as such things go. The measurements can be pretty precise, but is the air bubble actually the same now as it was at the time the bubble formed? uncertainty enters from that. Source material itself (the air) is not homogeneous so you need a good number of analyses to define a statistical population or you cannot really say anything about how well a single measurement is a representation of the real world (works for all analyses not just bubbles). The more data you have, the more confidence you can have. Other methods vary from stable isotopes (carbon, oxygen, hydrogen, sulfur isotopic variations all provide clues about the nature of ocean-atmosphere chemistry), global carbonate sediment production, weathering rates of rock (CO2 is a weak acid and main source of rock weathering), and lots of other chemical or physical methods of questionable certainty but still decently useful for more ballpark understanding. Obviously, when you get into larger scale processes covering wider time frames, precision is lost. I even knew one line of thought that relied on examination of paleosoils going back well into the Proterozoic. How much should we accept the conclusions? Hard to say. Generally speaking, the changes with/over time are clear and repeatable, but how they translate into actual numbers is a harder thing to declare. High CO2 periods over low CO2 periods can be identified. Is a \"high\" period at 1000 ppm, 2000 ppm? or what? That is part of the interpretation and it is open to discussion, if one is honest. Trends are fairly easy to identify, but putting hard numbers to the different points in trends is a lot more challenging. The BIG HEADS like Robert Berner and Dick Holland (both long departed from this world) were the ones who got into this sort of thing in a big way back when I was a student in the 80s. Don't keep up so don't know who is doing all the hot work now. Mandatory reading back then though." ], "score": [ 214, 44, 37, 16, 3 ], "text_urls": [ [], [], [], [], [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2nzrle", "h2o3trm" ], "text": [ "Earthworms are eating the tiny, tiny bits of organic matter in the soil the ingest. Think tiny scraps of leaves, wood bits, animal and insect poop, etc. They aren't carnivores because they don't *need* to eat flesh. I'm sure there is bits of flesh in the soil but it's mostly tiny bits of grass, roots, and other decomposing plant matter.", "Soil is a mixture of water, clay minerals (grains of rock even smaller than sand that become sticky because of static electricity), tiny rocks, and most importantly organic matter - bacteria, fungi, plants, even tiny animals. Most of this stuff is dead. The worms swallow up mouthfuls of soil and digest the organic matter. Worms are closer to omnivorous than carnivorous, but something that fills this ecological role of \"eats mostly dead organisms\" is typically called a detritivore because this role plays an important part in keeping soil healthy, something other omnivores don't do." ], "score": [ 7, 5 ], "text_urls": [ [], [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2o4cvd", "h2o1qro", "h2o5je5" ], "text": [ "Disclaimer: I'm not a scientist, but everything I'm stating here, I learned through a blog called Lab Muffin Beauty Science, aka Michelle Wong. She has a PhD in chemistry, and her posts and videos are well explained, backed up by research papers and a \"no BS/fearmongering\" stance. Firstly, sunscreen wears off over time, i.e. \"breaks down\" due to chemistry doing its thing and you being a living person who moves around and does stuff. Depending on the UV index in your area and how much sun exposure you're getting (including sitting next to a window, but excluding blue lights from the screens because those aren't a concern despite some headlines), you should to reapply your SPF every couple of hours. In terms of how much - with SPF, more is more. Your skin is bumpy, you may miss a spot, etc. There is a recommendation to use a certain amount (using a measuring spoon lol) but honestly, you can apply however much you want and you'd still need to reapply throughout the day. Your skin will sweat, you'll inevitably touch your face in one way or another, and so on. And lastly, SPF testing is expensive, and hard to do. A lot of SPFs offer actual protection lower than the one indicated on the packaging, this includes both smaller/indie brands as well as the big ones (look up the Purito sunscreen scandal on Michelle's blog). The primary goal of SPF is to protect you from getting cancer, so feeling sticky is something I personally go along with for the benefit of my health. You can look into wearing UV-protective clothing and avoiding going out when the UV index is very high to protect yourself, but SPF is generally something you should be using daily. The benefits of SPF far outweigh the cons. If you're using additional skincare products that increase photosensitivity of your skin (retinoids, acids), please either cease to use them during all of summer, or make SPF your religion.", "You can. The higher the SPF the stronger the formula. I had a dermatologist tell me to use a super high SPF sunscreen. When I asked if the lower ones worked she said yes but nobody puts on enough, so go with the higher one.", "SPF numbers tell you how concentrated they are. You can work out what percentage of UV gets through a (per the label) application by dividing 100% by the factor, so SPF 50 allows 2% of UV through, and SPF 30 allows ~3%. If you could get SPF80, that would be 1.25%. As you see, the higher numbers get progressively less effective (rather the difference between SPF 30 and SPF 50 is 1.3% or so, SPF50 to SPF 80 would be 0.75% difference). In other terms, SPF30 blocks 97%, SPF50 blocks 98% and an SPF80 would block 99% or so. All of them block almost all UV (with a rounding error) compared with no protection. SPF50 is about as effective as is useful whilst still not being a complete sun block (like the zinc creams which just sit white on the skin surface). Use it twice (once plus a top-up) and you're ahead of the game whilst not looking like a snowman. Different brands absorb differently - you'll find some which are less sloppy and greasy than others (generally cost a bit more, though)." ], "score": [ 30, 12, 8 ], "text_urls": [ [], [], [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2o7rrz", "h2o7kq8" ], "text": [ "In investmenting (and, in fact, generally), 'hedging' is when you when make sure that any \"exposure\" you have to a given company, commodity or industry - that is to say, money invested that you could lose if it all goes tits-up - is offset by investment in some other company, commodity or industry that is likely to move in the other direction. For example, you might invest heavily in natural gas, and if there's a cold winter the value of natural gas will go up. However particularly cold winters might also mean lower yields from certain crops like Floridian oranges. As such, if you invest in gas, you may wish to also invest in Floridian orange groves so that any particularly harsh tilts one way or the other are somewhat cancelled out. & #x200B; Hedge Funds are large pools of money (mostly coming from pensions, where long-term stability is prized over short-term gains) that seek to 'hedge' as much as possible so that the only time there's a real big loss to the total value is if there's a total stock market collapse. This hedging process means you're a lot less likely to suddenly make a load of money (because when one thing goes up, the thing you hedged it with goes down) but, as long as the total value of the market goes up, so should your fund. If your fund is large and diverse enough then you don't really need to worry about the tit-for-tat gas vs orange juice thing - simply having a large variety of investments will typically spread the risk wide enough that you benefit from these relationships without needing to meticulously predict them all (that is to say, if you buy enough different investments you'll probably end up invested in gas and orange juice anyway). & #x200B; It has uses in gambling, too, for the same reason (hur dur dur, investing is gambling!) If you bet on Team A to beat Team B, it might also be worth sticking a small bet on a player from Team B scoring a goal; It's not guaranteed to come in, but losing your \"main\" bet makes your little side bet more likely to come in. You're probably familiar with the term \"hedging your bets\", which means to sort of keep your options open without coming down heavily on one side or the other.", "They are investment funds run by firms for wealthy investors, with broad ability to invest where they see opportunities. They typically only take money from wealthy investors due to the high risk/high reward investing style. They might buy stocks, options, buy companies outright, invest in real estate, currency hedges, commodities/futures, or all sorts of other derivative investments out there." ], "score": [ 11, 4 ], "text_urls": [ [], [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2o6whq" ], "text": [ "A dividend is money that is paid to you (a shareholder or account holder) based on how much stock/money you have in the account. So every month, most likely, you’ll get that percentage of your account balance added to your account by the bank, as payment for letting them use your money." ], "score": [ 5 ], "text_urls": [ [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2obp7g", "h2ofggq", "h2oapcw" ], "text": [ "Cos god likes shiny things. Metals have things called delocalised electrons, which cause them to perform metallic bonding, in which those delocalised electrons kinda flow around the entire metal pretty loosely. This is contrasted with ionic and covalent bonding, where electrons are donated to create complete electron orbitals or shared to give both the benefit of full orbitals. Electrons are organised loosely into orbitals btw - each atom has a number of electrons equal to its number of protons, and these electrons orbit the nucleus at certain distances. Each distance can only contain a specific number of electrons (for example, the first orbital can only contain two) and once it's filled up, the next electrons must start filling a new orbital further from the nucleus. Delocalised electrons occur when the attractive force between electron and nucleus is quite low, which can be a mixture of an orbital that's incomplete in the wrong way and an orbital that's too far from the nucleus. This weak attractive force makes it easy for electrons to become dislodged and swap to the orbital of a neighbouring atom. The fact this can happen is what makes metals conduct electricity - delocalised electrons are free to move through the metal. If you look at a periodic table, you'll notice the atomic number, which indicates the number of protons in the nucleus and therefore also the number of electrons it comes with. This number starts at 1 for Hydrogen and increases one by one going left to right and top to bottom. The heavier atoms get, the more of them are metallic, because of this delocalised electron thing. The non-metallic elements at the right of the table are non-metallic despite being heavier than their neighbours because their orbitals are sufficiently complete that they prefer to bond ionically and covalently, instead of making a delocalised electron soup.", "Each atom has an electronic configuration on its last layer. Most of those configurations means you are a metal, due to being the \"midway\" point between \"wanting\" to \"grab\" a few electrons or to \"give\" a few electrons.", "The elements we've labeled as \"metals\" have thermal and electrical conductive properties, as a result of the fact that they have a lot of unpaired electrons that can easily move about and they tend to form crystalline structures in which the electrons can freely flow along the outside of." ], "score": [ 15, 4, 3 ], "text_urls": [ [], [], [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2obfxv" ], "text": [ "The sky is just as transparent during the daytime as it is at night (which is why we can see things like the Sun & Moon through the atmosphere). The difference is that the sunlight scattered in the atmosphere during the day is much, much brighter than any stars in the night sky, so their light gets drowned out like a whisper at a death metal concert." ], "score": [ 15 ], "text_urls": [ [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2oiwfk", "h2op343" ], "text": [ "It's a combination of things, caused by your immune system working way harder than normal for a bit. So, dehydration, nutrients getting sucked up by systems that aren't usually so desperate for them. Your immune system is running a marathon instead of just keeping you alive like normal.", "Your body prioritizes resources and energy use. Our muscles are constantly damaged from use, cells are being replaced, but when your body gets to fight the disease mode it reacts to everything harder. This causes inflammation everywhere where there is damage. Inflammation causes pain. Add to that to your body fixing itself slower. This leads to aches in the muscles. Our immune systems isn't as targeted as we like to think it is. When it ramps up, it ramps up everywhere." ], "score": [ 9, 5 ], "text_urls": [ [], [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2og2i1", "h2oh2c7" ], "text": [ "Typically not. You don't sign some sort of contract when you become a godparent. It is more of a social contract than a legal one. By designating a godparent the parents publicly indicate their wishes and the godparents publicly accept the responsibility. Either party could back out at any time and not experience anything more than social shame.", "The concept of godparents are purely religious and not legally binding in any way. The only similar concept in the laws is legal guardian but these gets appointed by the courts when needed instead of at birth. That being said if someone have been appointed a godparent by the parents it is likely that they may be appointed legal guardian by the courts if they want since they can prove that this was the parents wish. However this is not a fixed rule." ], "score": [ 28, 8 ], "text_urls": [ [], [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2ogl6o", "h2ohtkg", "h2okmuo", "h2onidg" ], "text": [ "Connection to the tower is good but the overall usage at the tower is high making everyone's connection suck.", "There is no actual standard for what the bars showing the connection actually mean. It is up to each phone manufacturer to select the conditions required for each bar. It could for example be that they are showing how good the strength of the signal from the cell tower is. If you are close to a cell tower you would expect a strong signal and therefore many bars. However this does not say anything about how much resources the cell towers have to spare your phone. It could be that there are hundreds of phones connected to the same cell tower, all with good connection to the tower, but they still need to share the same frequency space and the same outgoing connections.", "There are a number of reasons, but one common one that is not obvious is multipath. Multipath is where a signal is reflected off of nearby buildings/mountains/ground/etc, and results in the receiver seeing multiple competing signals. Imagine you were in a cave, and someone is trying to talk to you across a distance. If you were in an open field, you could easily understand them at that distance. In the cave though, the echoes of their voice reach your ears at slightly different times. Even though you are getting plenty of volume, it is hard to discriminate the message. With radio signals, it can be easier in some ways and harder in others. If one \"echo\" is significantly weaker strength, modern receivers can determine that the echo can be ignored, AND they can cancel out some of that echo to make it easier to hear the main signal. As more echoes are added, as long as one is significantly stronger than the others, it just takes more processing power and all the others can be filtered out. (This is one reason why newer phones seem to have fewer problems connecting to cell service. Newer CPUs and signal processors are smarter at filtering/discriminating, faster at detecting and correcting, able to handle more signals at the same time, and overall better at dealing with multipath.) The problem comes when there are two paths that are very similar, resulting in two paths that are about equal. Two paths that are about equal can result in about the same signal strength, and small changes (like the wind blowing tree limbs along one of the paths) can make one better than the other for just a moment. Plus, the same signal (same frequency) that takes different paths can actually cancel itself out in some places. (This is a bit complicated, but if you think about a lake, and there are two waves that meet, in some places the waves cancel out and the water does not go up or down.) The signal will essentially never completely cancel out, but it can cause enough of a problem to keep modern devices from having a good connection (again, even though it is getting plenty of \"volume\", ie., overall signal strength). In theory, cell phones could do periodic check-ins to determine how good their connections are, and display that instead of the signal \"strength\" bars. In practice though, that would mean a great deal more traffic for a small bit of extra information. One thing to try if you are having this issue is to turn on airplane mode for \\~15-30 seconds, then turn it back off. This will force your phone to check back in, and may allow it to connect to a \"better\" tower. (\"Better\", not necessarily closer. Due to multipath, one tower might be closer but go through/past obstructions that cause problems.) One hope for 5G is that there will be more \"towers\"/micro-cells, and less distance means less multipath. In practice, that may or may not help.", "You can see the carrier signal from the tower. Pretty well too, it seems. Unfortunately, the tower doesn't see you so well. Either because of obstructions, a weak LTE transmitter, or both. The problem with downlink is that your phone has to send constant acknowledgement of receipt back to the tower (Basically, \"Got that, send more\"). When the tower can't see the, \"Okay, send more\", it times out and begins pinging your phone. In that moment, the behavior of your phone is dependent on whoever manufactured or distributed it." ], "score": [ 49, 10, 6, 3 ], "text_urls": [ [], [], [], [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2oj4ym", "h2oivek", "h2or6av", "h2om0m5" ], "text": [ "Lumber industry was shut down temporarily, slowed by COVID--in part due to expected reduced demand in the early days and also due to COVID safety protocols, etc. And then instead of a reduction in demand, there was a surge as people wanted to buy bigger homes, wanted to remodel, wanted to build decks and swingsets, etc. So less supply, much higher demand led to a surge in prices.", "It's complicated. It started before the c-thing, with a shipping strike in Asia - there wasn't much shipping happening, then the c-thing happened and everything shut down, then as things got back going in Asia all the empty shipping container were in North America and not getting sent back because they were empty, then everyone was stuck at home and decided to improve their homes and used all the stock but they weren't making any more lumber, then the Suez canal thing happened....so many things!", "1) COVID hit and tree cutting/processing mills were slower due to isolation protocols while others were closed from outbreaks, therefore supply was significantly decreased, 2) people stayed home, worked from home and didn't go on vacations, therefore they renovated with their vacation cash, created necessary home offices and built their own backyard spaces, significantly increasing demand. 3) the combination of the two created the \"perfect storm\" that increased lumber prices 250-300% in some cases", "Long story short: the mills (the places that turn timber (logs) into boards) were shut down for a period of time in the pandemic which hurt the lumber supply. Since then the lumber mills have been operating at full capacity but it takes tens of millions of dollars and years to build a new mill and so nobody was interested in doing that in the short term to respond to a temporary bubble. That leads to a restriction in supply and prices go up because of that. The lumber futures (the commodity price people are betting on in the future) are starting to come down as supply begins to catch up with demand." ], "score": [ 15, 5, 3, 3 ], "text_urls": [ [], [], [], [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2oklnf" ], "text": [ "Heat causes things to jiggle. Bouncing electrons off of something to make a picture is harder if lots of electrons are bouncing away from your microscopes detector instead of into it. Making things really cold removes most of the jiggling. Less jiggle means more electrons bounce back to where you want them to in your detector. Imagine that hitting baseballs into the outfield would create a picture of the bat made out of baseballs. Now imaging your bat is wiggling and shaking like a pool noodle. More balls are going to go everywhere but the outfield. Eventually enough will make it there to create a picture, but it's not going to make a very good picture." ], "score": [ 5 ], "text_urls": [ [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2oljb8", "h2olczz" ], "text": [ "Its actually psychology, not biology. Basically the sound of running water is a conditioned stimulus and having the urge worsen is the response. We are conditioned to expect “release” when we hear that noise. Therefore, part of your brain is having the urge to let go but your body now has to fight harder to stop the urge.", "I'm not sure but my guess is a sympathetic nervous response kinda how yawning is contagious. In our monkey brain we hear water and our brain says \"this is a safe place because there's one of the things we need to survive nearby\" or \"there may be another person marking and I need to mark too\"" ], "score": [ 6, 3 ], "text_urls": [ [], [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2ospje" ], "text": [ "If the ice is much colder than freezing, it can also freeze the water in/on your skin and fuse to it. This only works if the ice is very cold and you’re kinda moist." ], "score": [ 5 ], "text_urls": [ [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2p6315" ], "text": [ "This has to do with the gyroscopic effect. In simple words, when a wheel spins (the same can be applied to whatever other objects in rotation motion), the rotation leads to forces that keep the wheels \"straight\" and balanced. Another \"funny\" thing caused by the gyroscopic effect on a two-wheeled vehicle happens during turning. If you are speeding and you need to go through e.g. a left corner, you don't have to steer left but you need to slightly steer in the other direction (so right). As a result, the two-wheeled vehicle will actually bend on the left and you can do the corner (see motoGP). But as I said, this can happen if you are speeding, so don't do that at 10 kph on your bike." ], "score": [ 3 ], "text_urls": [ [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2p610f" ], "text": [ "Cats for example are able to feel small tremors before the tsumani arrives. I'm assuming many other animals can as well. An asteroid doesn't have a similar warning sign. It's faster than sound so good ears won't help." ], "score": [ 3 ], "text_urls": [ [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2ozzu4" ], "text": [ "It gives additional stimulus to the nerves in the area, which distracts from the pain feeling." ], "score": [ 7 ], "text_urls": [ [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2pdfda" ], "text": [ "Artificial sweeteners in diet sodas are much sweeter than regular sugar so you need to add less of it to get the same sweetness. Diet sodas are usually > 99% carbonated water with < 0.2 grams of artificial sweetener. In contrast, regular sodas have a great deal of added sugar. A regular 12 oz (355 mL) can holds about 10 teaspoons or ~40 grams of sugar. This is about 10 sugar packets per can! Because there is so much sugar, the volume of carbonated water is lower in regular sodas so it can't hold as much fizz." ], "score": [ 11 ], "text_urls": [ [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2piaga" ], "text": [ "Bruises are just small bleeds under the skin. The dark patch you see is just some blood that's gathered in one spot under your skin. Bruises just heal by these blood cells dispersing or breaking down." ], "score": [ 3 ], "text_urls": [ [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2p8l5u" ], "text": [ "You're confusing a few different things. Lactic acid occurs during high intensity exercise when your body needs to metabolize glucose without oxygen. The burn is the sensation of that acid building up. Delayed onset muscle soreness (DOMS) is what occurs 24 or sometimes 48 hours later. That's when heavy lifting or muscle exertion causes micro-tears in your muscles, which your body responds to with inflammation to bring blood and nutrients to the muscles to aid in repair. You feel that inflammation as pain." ], "score": [ 8 ], "text_urls": [ [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2puifv" ], "text": [ "When a muscle cramps, it contracts forcefully and stays that way without releasing. A spasm is when the muscle contracts and releases repeatedly. I think a twitch is largely the same as a spasm, but there may be differences that someone else can clarify." ], "score": [ 4 ], "text_urls": [ [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2paqcb", "h2pb0nh" ], "text": [ "Older cars used pressure pads behind the bumpers. Newer cars use g-force sensor chips mounted in the cab to detect force, angle, and extreme changes in speed and direction.", "There are accelerometer sensors in the frame/body of the vehicle. These accelerometers triggers the airbags when they detect an acceleration due to impact that is above a certain threshold." ], "score": [ 16, 3 ], "text_urls": [ [], [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2pc6rl" ], "text": [ "For XP, Windows 95 and other older versions the key wasn't actually all that unique, it just had to fit into a specific pattern. For example [111-1111111]( URL_0 ) was a valid Windows 95 key because the last 7 digits add up to a multiple of 7" ], "score": [ 9 ], "text_urls": [ [ "https://www.youtube.com/watch?v=cwyH59nACzQ" ] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2pseii", "h2qoh89", "h2prxsi" ], "text": [ "The top number is referred to as the systolic blood pressure, and the number is a measure of the pressure of blood against the walls of your arteries as your ventricles (lower two chambers of the heart) push blood throughout the body. The bottom number is referred to as the diastolic blood pressure, and the number is a measure of the pressure of blood against the walls of your arteries as your heart relaxes and the ventricles fill with blood. This is also the period where the heart relaxes in between heart beats. Generally speaking, a systolic pressure higher than 120 is a problem, whereas a diastolic pressure higher than 80 is a problem. So there isn't really an issue if you are below those values except if they get too low (such as 90/60 or below).", "ELI5: top number is when the heart is squeezing. The bottom number is when the heart is relaxing. ELI 15: top number is heart squeezing blood out of the heart. Your arteries resist this (because equal/opposite reaction). Bottom number is heart relaxing… your arteries still push back. As for health of the numbers, that’s a little more than ELI5… but the basics are you want all of the numbers to be lower, including your pulse rate. A heart that only has to beat 60x per minute to perfuse the body is healthier than a heart that has to beat 100x per minute. The normal range of heart rate for an adult is 60-100, with 60 being on the much healthier side. For blood pressure, it’s the same thing. You want the lowest blood pressure you can have. With that, you need something called an “mean arterial pressure”, because you heart pumps blood to all your organs. One of those organs is your kidney, and that needs a mean arterial pressure of 70, otherwise there isn’t enough pressure to filter your blood properly. A BP of 90/50 would be adequate (depending on the person), but a BP of 90/60 would be more safe(as we want the MAP to stay above 70 at all times, and 50 has the potential for your map to be lower than 70)…. 120/80 is considered average. 90-139/50-89 is considered “healthy”. Below those numbers and your kidneys and brain don’t function (or won’t for long). Above those numbers you start looking at stroke range. Then you get into complicated things like a widened or narrowed BP. 100/90, for instance, is a very dangerous BP, as is 180/60 (but for different reasons).", "Top number is how much push when heart is beating. Bottom number is how much pressure between heartbeats. 80 on the bottom counts as \"elevated\" so it's just barely too much but not quite considered \"high\" Too low is not great (mine is usually in the 50s), but it's less harmful than too high." ], "score": [ 138, 64, 7 ], "text_urls": [ [], [], [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2puxwk", "h2pya3u", "h2pzgcw", "h2puphw" ], "text": [ "Things bounce around in the dish washer, your blade is knocking off other things which can over time lead to tiny chips, bends etc. And leaving them in water causes oxidization and degrades the edge over time. A knife is sharp because the edge is very thin and straight. When things happen to make it less straight or less thin it becomes less sharp.", "In addition to the metal comments, most \"good\" knives have wooden handles. The water and heat combo will destroy the wood in short order.", "Dishwashers clean using very high heat, force, and abrasives. All of those things will blunt a knife's edge. This isn't an issue for things like butter knives because they're essentially blunt already, but they'll ruin a good knife.", "Knives (good ones at least) are made from a different type of metal (non plated) they are much more susceptible to rust. Any rust/oxidation on the edge of the blade will make it dull" ], "score": [ 11, 7, 6, 4 ], "text_urls": [ [], [], [], [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2qg3k5" ], "text": [ "You could technically consider the cerebellum as the trigger. It's more like they send impulses to other parts of the body and let your emotions be physically rendered as crying, laughing, etc. In this case, the cerebellum triggers the lacrimal glands (tear glands). I don't know exactly why we cry with tears, but I've always imagined it has a lot to do with the way humans have evolved. Since we tend to be a very social species aside from the rare Reddit breed, tears can be seen as a way to show and share our emotions with others -- basically a biological \"I feel pretty terrible right now. Pls help.\"" ], "score": [ 5 ], "text_urls": [ [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2q7v9x", "h2qs9p1", "h2q6qd9", "h2qeuwg", "h2qqftm" ], "text": [ "Bounces don't give you concussions, your brain has some cushioning and can move around a bit in the head. what does cause concussions is rapid movements (like whiplash getting hit, or in a car accident) or sudden stops (like falling on the ground and hitting your head hard) that cause your brain to move TOO MUCH and hit/squish up against the skull. imagine it like a cup of jello. You can toss it around and catch it and the jello has enough give and take to handle it fine. It is when you drop the cup of jello on the ground or it hits a wall that problems happen.", "If you put tofu in a jar mostly full of liquid and are asked to damage the tofu as much as possible without breaking the jar or opening the jar, how would you do it? The trick is to get the tofu and the jar moving in opposite directions so the tofu is moving one way and the jar is moving the opposite way and the two collide. I can think of two ways to do this: shake the jar left then right, then left then right. The tofu will move left and because of interia will keep moving left when I suddenly move the jar back right. The tofu won't be moving very fast nor will the jar, but you can manage to smash the tofu into the jar many times repeatedly. The other way is to get the tofu and jar to go really fast (say, in a car.) Then suddenly slam on the brakes while bracing the jar. The tofu will continue to go at high speed because of inertia but the jar will be stopped. Tofu will slam into inside of jar at high speed. Now, compare this to tossing jar and tofu into the air and catching jar and tofu gently. As jar and tofu hit the highest point, gravity is slowing the jar and tofu... Until both jar and tofu are at zero speed, then jar and tofu slowly accelerate again as they fall. Now, if you stop the jar as it called really suddenly (say, it hits a stiff net) the tofu will continue going and slam the jar. But of cradle catch the jar and slow it slowly, tofu will not slam the jar. That's what happens when you land jumping: your ankles, knees, hips, spine all compress as you land, cradling your skull and brain so they slow down slowly together. The jar and tofu are never going in opposite directions, the jar is just slowing a tad faster than the tofu. Plus you don't jump very high so you don't actually fall very fast. Good ways to get concussions: shake back and forth in opposite directions like a football player getting hit in the opposite direction they are running. Or go really fast and stop suddenly like a car accident (when the seatbelt stops you, it will sling you back the way you came and you will bounce back and forth like the football player.) Basically, brain and skull need to be going in opposite directions.", "There is a layer of cerebrospinal fluid surrounding your brain that cushions minor impacts.", "The same reason landing correctly does not hurt your joints. Basically the whole point of a safe landing is to decelerate gently, by distributing the landing force over time and space. These more gentle forces are then within the range that your body can handle without injury.", "If you have a tomato in the jar, and bump the jar against the wall, the tomato will be fine. If you take the jar and slam it into the wall, it will not be." ], "score": [ 45, 15, 12, 5, 3 ], "text_urls": [ [], [], [], [], [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2q8wmo" ], "text": [ "Most devices generate all of those different voltages with their own circuitry because they can control how noise free it is, the efficiencies, the maximum current capability, all while only requiring a single external voltage to do it. This makes it simpler for other people to integrate their device into other systems. Especially since 12V is so common, but some more obscure required voltages like 1.2V, 0.9V, to name a few are not but may be required by the internal circuits." ], "score": [ 7 ], "text_urls": [ [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2qocfh", "h2qj8vt" ], "text": [ "Different species have different tactics. Dolphins will only sleep with half their brain for 2 hours a piece, remaining still enough that it is called logging. The awake half literally keeps one eye watching for predators and will surface for breath. URL_0", "If I recollect properly I think they do like fish and just sleep half their brain at a time. Or I’m totally wrong" ], "score": [ 6, 5 ], "text_urls": [ [ "https://www.scientificamerican.com/article/how-do-whales-and-dolphin/" ], [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2qlh5u" ], "text": [ "Absolute time will only go forward and thus positive. Relative time can be negative: \"I arrived three minutes before the rest of my party\", \"Launch in T minus 15 seconds\". The current understanding is that time in this universe started at the moment of the Big Bang, there was no time before that as there was no universe before that." ], "score": [ 3 ], "text_urls": [ [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2qo8zh", "h2qmrll", "h2qonu9", "h2qn7tn" ], "text": [ "By using different measures. Some use coverage in terms of ground covered. Some use coverage in terms of number of people covered. Then they could be counting number of dropped data connections or average data speed. Despite what others are saying, there are laws in advertising and the measures they have used will be available somewhere - either in the small print in the ad or on their website", "Local law does not prevent them from making such claims not supported by consumer consultation or specific testing. When legislation requires that such sayings be proven, companies do not say those things.", "\"Covers most area\" \"Covers most people\" \"Fastest 5G\" \"Most reliable 5G\" All of these mean different things.", "They also don’t usually define which “area” so it’s a pretty broad statement that can be interpreted in various ways. Best bet is to check out their coverage maps." ], "score": [ 19, 10, 5, 5 ], "text_urls": [ [], [], [], [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2qnet4", "h2qt28i" ], "text": [ "moisture is a breeding ground for bacteria, in general any food product that has moisture in it will expire faster then something dry. Its why people dehydrate things like beef jerky to make meat last longer", "The microorganisms that spoil food need some level of water or moisture to live. When it’s a powder it’s pretty resistant to anything living in it but once you add water it becomes a nutritious feast for bacteria and molds. In general, dehydrated or dry foods have quite a long shelf life for this reason. However, microbial spoilage isn’t the only way food can go bad. Other processes, like oxidation of fats take place on their own over time, as long as there’s exposure to air. This is why even some fully dry foods have limited shelf life (like brown rice being good for about six months in the pantry)." ], "score": [ 10, 5 ], "text_urls": [ [], [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2qpolz" ], "text": [ "Allergies are an false alarm of your immune system. An overreaction to a harmless substance. The immune system is highly complicated, and not reacting to something dangerous might kill you, so it rather reacts too much than not enough." ], "score": [ 4 ], "text_urls": [ [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2qtkof", "h2qq75h", "h2qqxi0", "h2ri74x" ], "text": [ "ELI5: Your body picks up a heavy thing repeatedly and muscles tear under the stress. Your body recognizes that you now pick up that heavy thing repeatedly to stay alive, it dedicates resources to regrowing those muscles that were torn and build enough new ones to handle picking up that weight so you don't die. Repeat.", "To put it simply, when you exhaust your muscles by doing anaerobic exercise (i.e lifting heavy objects at the gym), you cause damage to the muscle tissue and cause tears. If you provide the body with good quality protein and enough calories, the body repairs this damage and applies some more proteins to the structure for good measure, which makes the muscle bigger. This process is called Hypertrophy.", "There are a few processes that make your strenght, one is the thickness of you motor units (your muscles) which respond to mechanical stress by growing thicker (classic hypertrophy training with 8-12 reps tries to maximise this). The next is intermuscular coordination. That is essentially how well your body is able to coordinate your muscles during the exercise. That is something your brain just learns when lifting heavy things. Your brain is quite good at this, that also happens for running (experienced runners run more efficiently). The last is intramuscular coordination. That is the ability of your muscle too recruit his muscle fibers in the most effective way to do the task. It is something your nervous system has to learn. That best works in lower rep ranges as you are forced to adapt to the high stress.", "There are three major parts: 1. When you lift heavy stuff, you have to work hard. Your body doesn't like working hard. So over time it grows muscle so you don't have to work as hard when lifting things. Once you stop lifting things your body will get rid of the muscle since it's just dead weight. (train this part by lifting heavy) 2. Same thing basically happens when lactic acid builds up in your muscles, it hurts. Your body doesn't like pain so it makes bigger muscles to have more lactic acid capacity and less effort. Again, once you stop using those muscles it's just dead weight and your body will get rid of them. (train this part by exercising for metabolic stress. So lighter weight but repetitions untill you really feel that burn) 3. As said by other, your muscles tear when lifting or exercising. When those muscles are repaired, the repairs make the muscle (fibers) slightly bigger every time. (train this part by stretching the muscles under load and doing good controlled 'negative' parts of the exercise.)" ], "score": [ 52, 16, 4, 3 ], "text_urls": [ [], [], [], [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2rcbup", "h2r4vpu", "h2rhkjh", "h2rdei4", "h2rjpnw", "h2rd5i7", "h2rbi45", "h2stvq7", "h2t8bhq", "h2rcq4k", "h2rjuw2", "h2rlwcb", "h2sm42x" ], "text": [ "It's instinctual. Birds reared in plastic containers build their own nests just fine. They need not ever see a nest to build one. Further, the nests they build don't necessarily model the nests their parents built. If a researcher provides a bird with only pink building materials, the chicks reared in that pink nest will choose brown materials over pink for their own nests, if they have a choice. There is an instinctual template, thank god. Imagine being compelled to build something but having no idea of what or how. Torture! That's not to say that birds are slaves to their instinctual templates. They gain experience over successive builds and make minor changes to the design and location.", "Birds can learn from their own nest-building experience, while other studies suggest birds may learn by example from their parents or other familiar birds. So they either use trial and error for the materials to use or they watch their parents and or similar birds’ nesting habits and mimic their nests. It’s actually pretty cool to think about how smart some animals really are!", "It varies by species. I can bring an example of a species that is genetic (I can't remember the exact name of the species unfortunately). This is a spider that weaves a spider web container to protect its eggs. The motions to complete this are quite complex, and they never see an other spider do this (they always do this hiding in their nest), so it can't be learned. Furthermore, if you interrupt it, and take away the half complete container, it just continues to make it. It can't detect errors, it's all \"pre-programmed\".", "I'd like to bring up the topic of Sperm Whales here because AFAIK their complex behaviours (mainly their social coda communication) is entirely behavioural. Sperm whale mothers and calves have codas, which are a series of clicks that they use to communicate with one another, as well as other individuals. Studies have shown that coda dialects exist, and that individuals that use the same dialect preferentially choose to be with one another to form social units, much like how humans may find it easier to make social groups with people who speak the same language. What's interesting with Sperm Whales is that there is evidence that these coda dialects are entirely learned, as there is a period of time in which Sperm Whale calves have trouble mimicing, or using other coda dialects know as \"babbling\". Calves can learn from their mothers, or learn a different coda via horizontal learning. Whats more is that these dialects have even shaped the genetics of the Sperm Whale dialect groups, as opposed to the genetics affecting the coda dialects. Sorry for the long reply, but its a neat example and just wanted to throw my hat into the ring", "I saw a documentary that the birds have an instinct to do it and each year their nest building gets better. I also read some researchers cut a hole in the bottom of a nest to see what would happen and the bird just kept laying eggs and they would fall through, it didn't comprehend.", "There is ongoing debate in the biology community about how much of instinct as we currently understand it is imprinted in DNA. Obviously there has to be some and maybe all of it, or some other thing we haven't found yet. For example, human babies know immediately how to cry, how to laugh, and how to smile. No one taught them that... or did we? Mothers immediately smile when they see their newborn baby. Is the child mimicking or not or a little of both? Mothers also cry in joy when they first see their babies. They also laugh. So it is unclear what is really going on. The same holds for all animals. It's been a question thrown around for a very long time. The issue is that it's just extremely hard to design an experiment that tweaks out that precise question all the while being both morally and ethically consistent with our beliefs as people. We can do all sorts of experiments if we throw those guardrails out the window, but we won't. Edit: If we did take the guardrails off for experiments, it's still unclear if good science would result. The Nazi's are a textbook example. They performed all sorts of horrific experiments, but with genuinely clear goals in mind like hypothermia, pain tolerance, longevity of fetuses, and to the point of this discussion the permanence of instinct (I'll let you imagine the horror of how they went about that). I hate to say it but some very good data did come out of those experiments, and American scientists stole it and in return spared many German scientists lives who should have hanged. All graduate students at my University were required to take an ethics class and we went through all of this. It's sad and tragic, but it indeed happened. Edit2: It is entirely within our current framework of science to do all of what you suggest. But we can't because we as scientists are bound by moral and ethical responsibilities, legal matters, and the bounds of how grants are funded. That's our current framework and I believe it's the right thing to do. /biochemist and functional genomicist", "Even if there are birds that do suck at building their first nests and learn from helping other more mature birds. That doesn't explain spiders which do not cooperatively build their webs or have any social interaction with their parents or others of their siblings. And yet each species of spider can build the complex architecture of it's web in a manner identical to the form used by others of it's species. I've never understood how architecture can be inherited and imprinted in a brain no bigger than the period at the end of this sentence. Same goes for all \"builder\" animals. I just don't think we have ever understood and explained the mechanism. And we likely never will.", "I'm not sure if this is relevant but I'm from the Chicago area. There is a place called Calumet City that has a population of green parrots (or parakeets, I'm not sure of the exact type) that had gotten loose from either a private owner or a pet store. Since the birds were from a warm, tropical area they were not expected to survive the harsh Chicago winter. But they did. It turns out that they had figured out how to build nests that were fully enclosed and kept them warm and dry enough to survive until spring and summer. I believe there is a documentary about them. The point I'm trying to make is that the birds were able to change how they built their nests in a single season.", "It's genetic. Dawkins explains it all in The Extended Phenotype: [ URL_0 ]( URL_1 ). It's an excellent read.", "Birds have nest building instinct but also improve via repetition. Some birds may learn from observation of other birds but many do not seem to rely on such.", "> Nest-buildingis not just instinctive but is a skill that birds learn fromexperience, research suggests. University scientists filmed maleSouthern Masked Weaver birds, in Botswana, building multiple nests out of grass during a breeding season. [ URL_0 ]( URL_0 )", "Awesome question! I have no idea and even though I'm a huge animal lover I didn't get how incredible their specificity and ability to learn is. Check out Life in Color on Netflix if you have it. There is a bird of paradise scene where a male is cleaning and prepping and area. He starts calling for a mate and the first like 9 birds to get there are others male..... looking to learn! Incredible program. The camera work is ludicrous and they overlay the \"colors\" the animals would see with specialized camera tech. Obviously I'm sure we can't really know what they're seeing but I bet it's pretty accurate. So strange does it look you'll find yourself being like \"is this completely computer animated?\" Multiple times throughout the program because the volume of incredible footage plus the strange coloration. Must watch if you love life.", "Culture is really only found in animals which are at top of food chain AND have leisure time in which to express the culture. It's seen as \"sexy\" to have loads of downtime to do cultural stuff because it suggests to mates you have the basics like food and shelter squared away with ease. Humans, crows, dolphins are a few examples of animals with culture. Pretty much everything you see animals do as a solo activity is instinctual." ], "score": [ 4102, 1139, 228, 102, 87, 35, 12, 6, 5, 5, 4, 4, 3 ], "text_urls": [ [], [], [], [], [], [], [], [], [ "https://en.wikipedia.org/wiki/The\\_Extended\\_Phenotype", "https://en.wikipedia.org/wiki/The_Extended_Phenotype" ], [], [ "https://www.ed.ac.uk/news/all-news/birds-260911" ], [], [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2r70zs" ], "text": [ "Couple things before getting in to the nitty gritty. First, the cardiopulmonary system is just a fancy plumbing station. There is nothing mystical about the heart, it’s just pressure gradients and tubes. The blood will always move from an area of high pressure to an area of low pressure. Second, there are many ways to cannulate but I’ll be speaking broadly. The process of rerouting the blood to the bypass circuit is known as cannulation due to the fact that it needs two main cannulas, which are just huge catheters. One goes into the main venous system (usually through the Right Atrial Appendage) and sits in the IVC (inferior vena cava) which is the main vein coming from your lower body. The other goes into your ascending aorta, just beyond your aortic valve. Blood is removed by either gravity, suction, or both from the venous side, put through an oxygenator that removes CO2 and loads O2, and pumped back into the aorta. The aorta between the aortic cannula and heart is then cross-clamped and the heart is chemically arrested. This provides a bloodless, immobile, surgical field. The first image [here]( URL_0 ) gives a good visual. Can answer questions if you need" ], "score": [ 3 ], "text_urls": [ [ "https://thoracickey.com/blood-pumps-circuitry-and-cannulation-techniques-in-cardiopulmonary-bypass/" ] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2r39ne", "h2r3ovi" ], "text": [ "Buoyancy and water displacement. They float because they weigh less than the water they displace. The boats may be very heavy, but the inside of the boat is mostly just air, so the water they displace is even heavier. The heavier water is pushing back up against the bottom of the boats keeping them afloat. A ship stops floating and sinks when it weighs more than the water it displaces (like when there's a hull breech - like the Titanic).", "Buoyancy. When you put something in water, it displaces water equal to its volume - so the water that would have filled up the space it takes up gets shoved out of the way. Something will float when the mass of water it displaces is more than the mass of the object. So if you have a rock, rock is heavier than water is, so the mass of the rock is greater than the mass of an equivalent volume of water and it sinks. If you have something light like a piece of styrofoam, the mass of the styrofoam is very small, and much smaller than the mass of that volume of water, so the styrofoam floats. Giant boats work because overall they don't actually weigh very much in comparison to their volume. While you have things like the hull, engines and cargo that are very heavy, the mass of these is offset by all of the air inside the hull - all of the volume in the corridors, rooms and space between the heavy bits effectively weighs nothing, so when you add them together and average the whole weight against the volume of the ship, it is less than the mass of that volume of water - the empty spaces counteract the heavy bits." ], "score": [ 23, 7 ], "text_urls": [ [], [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2r5wd6" ], "text": [ "Trees use the leaves to photosynthesis and produce sugar that they can use to make more complex chemicals. The plants do need sugar to grow leaves. But it does not need to be produced at the same time. Trees produce sugar in the leaves and transport it to the rest of the tree where it is used and stored. When they grow leaves they use stored sugar to make them. Maple syrup is made by tapping the sap from maple trees. The sugar in it was produced last year and the tree uses the sap to transport it to grow leaves. If you look at trees they use carbon diode and water to make sugar and oxygen during the day. But they still grow during the night and then they use sugar and oxygen and produce water and carbon dioxide as we do." ], "score": [ 4 ], "text_urls": [ [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2r7pmp", "h2r6gk1", "h2r6kf9", "h2r6ulo" ], "text": [ "It's in the bloodstream. However, it's important to understand that most of your bloodstream by mileage is made up of capillaries. Capillaries are microscopic. You don't realize they're there because you factually can't see them. They are, however, still separated from the cells around them. Your bloodstream is a river, the rest of your cells are the shore. Capillaries are nearly everywhere in your body. You just can't see them.", "Think of your body as being an entire country and each cell in your body as being an individual house. Each house is on a small road that is connected to bigger and bigger roads that allow cars to get around just like how each cell is connected to a small blood vessel that is connected to bigger and bigger veins and arteries. Our cells aren't full of blood, but they all have contact with our bloodstream as that's how they get supplies to work and dispose of waste.", "Blood is only in the vessels normally. It flows in arteries, veins and capillaries, which are like a network of very small vessels on the surface of your skin and throughout your entire body. Blood itself is made up of different things - most importantly are the red blood cells but there's also fluid that has proteins and other stuff in it called 'plasma'. Normally, the cells are in suspension (kind of like a silty pond). Because of the way your body is designed, some of the plasma can leak out through capillaries into the space around it. There are also special cells (cells are filled with fluid) that can take up some water from the blood and change the stuff in it, and then secrete it back out. That's what mucus (and serous fluid) are. Both of these keep your body wet. The body also absorbs that fluid through your lymphatics, which are a different piping system and filters it through lymph nodes and eventually dumps it back into your blood vessels.", "Blood is in veins only, however veins are literally everywhere, even if you don't see them. That's why with most injuries also veins are broken. When looking at your arm you probably get the impression that blood flows only in the veins that are visible there, but those are only the big branches. Actually there are many many thousand, probably millions of branches that get smaller and smaller and go everywhere, to basically every millimeter of your body, including your skin. When including all the tiniest veins, an average human has around 100,000km of veins combined." ], "score": [ 11, 11, 6, 3 ], "text_urls": [ [], [], [], [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2rc91w" ], "text": [ "Our bodies are constantly producing heat and so as not to overheat we need to constantly shed that heat in to our surrounding environment. The hotter our surroundings get the less efficiently we can do that, so we start to feel hotter and hotter. What we consider to be \"room temperature\" is the temperature that is ideal for us to be able to shed heat at the same rate that we create it internally." ], "score": [ 14 ], "text_urls": [ [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2rfllr" ], "text": [ "They have different muscle mass (which produces heat), different metabolisms and resting heart rates (which also produce heat), and different amounts of fat (which keeps the heat in). People also wear different clothes, which change their body temperature." ], "score": [ 5 ], "text_urls": [ [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2rfizx", "h2rfnld", "h2rjewj" ], "text": [ "Because we now have newer technology meaning that the quality of photos/videos are better. We are used to seeing better quality images so anything from the 90's now looks old because it is lower quality.", "Analog photos normally had quite good quality, videotapes on the other hand, had quite bad quality. You can see this difference disappear when digital storage appears in the 2000's and we get equally bad photos and videos", "Being used to. Eat hotdog soup for years, it will taste OK. Get used to great food, and the hotdog soup will suck. Just to clarify, I'm not saying hotdog soup tasted bad, at all." ], "score": [ 8, 6, 3 ], "text_urls": [ [], [], [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2rgxm7", "h2ricqp" ], "text": [ "There is some air in the can, normally just sitting in one piece/bubble at the top. When you shake the can, you break that bubble and mix it with the liquid, creating thousands of small air bubbles. Now when you open the can, the pressure is released and the CO2 dissolved in the (carbonated) liquid vaporizes out of the solution and becomes gas. It’s a lot easier for CO2 to do that when there are already many bubbles of gas (air) which it can join. So a freshly shaken can will fizz out because of all the CO2 suddenly becoming gaseous. In a short while after shaking the air recollects in one bubble at the top, and it’s no longer so easy for CO2 to come out of solution, making the drink “settle down”.", "It's often said that shaking a bottle or can of a carbonated beverage causes the pressure to build up, so that when you open it, the beverage explodes. This is a myth. Assuming the container wasn't recently re-sealed after being depressurized, the pressure will not change inside. A carbonated beverage is filled with dissolved gas. Carbon dioxide, to be specific. They can force more of it in there at higher pressures, so the can or bottle will be pressurized when you first open it. After releasing pressure for the first time (that first *fssst!* sound when you crack open the seal) all the trapped carbon will want to come out. But the gas is mixed in all over the liquid, and it can only escape at the surface, which is a very small area, so the drink \"goes flat\" relatively slowly. What's really going on when you shake the beverage is you're causing very tiny little bubbles of trapped gas to get stuck all over the inner walls of the container. By doing this you're basically increasing the surface area of the liquid contacting air and spreading it all throughout the container. Release pressure when the container is like this, and suddenly trapped carbon dioxide all over the drink has a short path to escape all at the same time. This causes all the tiny bubbles to grow quickly and explosively at the same time. The opening on the container funnels all of this foam through a single opening, causing it to spray out with considerable force. By waiting a while, all the tiny bubbles stuck to the walls of the container eventually unstick and rise to the top. If you get rid of these bubbles, you get rid of the foam explosion. Life hack: flick the sides of a shaken carbonated beverage container with your fingers. This will knock the tiny bubbles off of the walls and make it safe to open right away." ], "score": [ 6, 6 ], "text_urls": [ [], [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2rfphl", "h2rm9q4", "h2riztm", "h2rg3t6" ], "text": [ "They have to be rapidly preserved in some way - buried in a landslide or volcanic eruption, deluged by a massive flood, fall into a tar pit… Typically petrified trees aren’t trees that randomly fell over in some primordial forest, the entire forest was destroyed in a major disaster and buried before decomposition could occur.", "Because the parts that did rot didn't last to get petrified. You don't typically find a whole petrified tree, just part of a trunk buried in ash or mud from volcano or local flood. The rest of the tree would have rotted away.", "Petrified wood forms when woody stems of plants are buried in wet sediments saturated with dissolved minerals. The lack of oxygen slows decay of the wood, allowing minerals to replace cell walls and to fill void spaces in the wood. The lignin is hydrophobic (water-repelling) and much slower to decay.", "\"Rotting\" isn't just a thing that happens but is rather a series of biochemical processes. Chemical reactions due to exposure to the elements and biological reactions as a result of other organisms literally feasting on the thing that is \"rotting.\" If you prevent the object from being expose to the elements and prevent access to it by scavengers, then the rotting process is significantly curtailed. Burying something very quickly after it dies is one way to do that." ], "score": [ 10, 3, 3, 3 ], "text_urls": [ [], [], [], [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2rj3g3", "h2rjoyi" ], "text": [ "Substances that burn instead of melt have combustion temperatures that are lower than their melting points. Before they have a chance to be heated to a temperature high enough to melt, they react with oxygen in the atmosphere and combust or burn.", "Any *matter* can melt (or vaporize directly in some cases) Burning only happens when a chemical reaction can happen. Paper+Oxygen for example makes CO² and water (like all other organic substances) Some other molecules aren't stable at higher temperatures, so it kind of reacts with itself. Fire IS a hot gas. It stops being fire if it's not hot. Thats like saying ice can't melt, because when it melts it stops being ice. Light is basically just EM radiation, and not matter at all. Also a bunch of elements need quite extreme conditons to reach certain states. Helium for example needs extremely low temperatures to condense to a liquid, and high pressure on top to freeze it (-272°C at 25 times the athmospheric pressure)" ], "score": [ 6, 6 ], "text_urls": [ [], [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2rjoob" ], "text": [ "Wait I think I can answer this! Apparently it’s because of the drop in pressure, which is why some people claim to be able to feel when it’s about to rain." ], "score": [ 9 ], "text_urls": [ [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2rrkmh" ], "text": [ "So this depends on a lot of things. Not every single variety of chrysanthemum will even last the same amount of time. Agriculture is just selecting the next generation of plants based on a series of desired traits. Many plants have lots of varieties of the same species that were grown by farmers. So like there are thousands of types of apple. There are many different varieties of corn. And there are many different varieties of roses. Some of those varieties were selected for having the best smell. Some are the brightest color. Some of them were selected for lasting the longest after they have been cut. It's not always possible to select for every single desirable trade at once. It's possibly you have to choose between planting seeds of flowers that had the best color versus planting the seeds that had the best smell. Depending on the market, and what they think they can sell, those desired traits will change. So the reason that some flowers last longer than other ones, at least in terms of commercial agriculture, is that we designed them that way." ], "score": [ 3 ], "text_urls": [ [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2s6ovb", "h2s577l", "h2s2098", "h2s916v", "h2s6pyy", "h2u2lia" ], "text": [ "Speaking only for Spanish, they don't. Gender is inseparable from the structure of the language, and it permeates everything. The verb conjugations depend on the gender of the subject. Most gender-neutral proposals for Spanish involve grammar and syntax gymnastics to structure your sentences to avoid using the undesired pronoun. It creates cumbersome sentence structure and reduces communication efficiency. They've tried some silly things that combine -o and -a word endings by using the \"@\" symbol. So instead of saying \"las manzanas\" you would use \"l@s manzan@s\" which is only apparent in writing, because the pronunciation doesn't change. English is a very fluid language, evolves rapidly, and has a high tolerance for new words. Many world languages are not similar in that regard.", "That's a pretty interesting question. I'd like to know the answer as well. I'm not sure how it's handled in Chinese, but in spoken language, the word for \"he/him, she/her and it\" are all the same (ta). The written characters are a bit different, though, but it would be almost impossible to misgender someone in conversation. It would be also be very weird to use \"them\" the ambiguous way we do in English because it's the same as he/she but with another word on the end which indicates a plural.", "I mean when it comes to pronouns English is pretty basic. some languages follow the same style of just using another (plural) pronoun, some have pronouns that dont indicate/carry gender and use those and in some others people apparently invented new ones (though I dont know any examples for that)", "Some languages don't have gendered pronouns. Like Turkish. Here the pronoun for the third person is \"o\". One single pronoun for everyone. It's a gender neutral term, because Turkish in general is a gender neutral language (we don't have grammatical gender)", "Those that have gender-neutral pronouns already often use those (English fits this category, and yes \"they\" has been a gender-neutral singular pronoun for ages and is grammatically correct. The reason it feels off is because it's impersonal, not because it's also plural). Some languages have also invented new gender-neutral pronouns and terms, such as \"hen\" in Swedish or xe/xer in English, but these don't always catch on. Some languages already lack pronouns entirely, often using gendered nouns instead like \"that man\", which can be replaced with gender-neutral nouns in a similar way. Then you've got languages in which all nouns are gendered, often through suffix modification, which are apparently a nightmare for non-binary people. For example, German has no gender neutral word for \"student\", only \"male student\" and \"female student\".", "My main language is french. What I do and seen others do to is just invent it, comming up with new words and evolving the language with the people that speaks it. There is \"iel\" for a gender neutral pronoun. It is true that a lot of words are gendered like adjective and stuff. So far i always a way of saying the same thing in a different way as to not misgender someone, but still conjugate the words within the sentence. an example would be instead of saying \"tu est aventureuse\" wich is \"youre adventurous\" (feminine). you can say \"tu est une personne aventureuse\" (you are an adventurous person). the \"adventurous\" is still feminine but you conjugate it with \"person\", wich is feminine, and not because of the person youre referring to. Hope this makes sense!" ], "score": [ 19, 14, 4, 3, 3, 3 ], "text_urls": [ [], [], [], [], [], [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2s568j", "h2sfpc0" ], "text": [ "Duck reproductive systems do have a benefit if it is to prevent unwanted mating. Making it harder to mate with females, makes it so females that have with that trait only mate with the best males. The females that mated with the best males have the strongest children, and their traits get passed on over females that were mated with weaker males.", "Evolution doesn’t pick the best traits, it just picks the traits of the members that managed to survive long enough to procreate." ], "score": [ 6, 3 ], "text_urls": [ [], [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2swnf3" ], "text": [ "Because moving those assets to Asia would not be advantageous. There's no reason their assets need to be geographically proximate to where their profits come from, and western countries tend to have highly developed and stable legal systems and regulatory frameworks which are what a bank like HSBC relies on. There may also be additional factors such as time-zone (Europe is the optimum location because it's near the economic centre of gravity of the world) and talent (HSBC may have found that Europe/America have the best talent pools from which to recruit their employees)." ], "score": [ 3 ], "text_urls": [ [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2s7ih6", "h2s83oi" ], "text": [ "There are two main things at play, 1. The density of the material at that heat is very low 2. You don't let it touch the container Most fusion experiments involve somehow confining the plasma so it can't touch the container walls, while this plasma is very hot the heat transfer to the container is relatively slow as there is effectively a vacuum between them. There are a few ways to confine the plasma, for example you can use a magnetic field because the plasma is made up of charged particles. Also this plasma isn't very dense, the pressure inside of these reactors is typically even less than atmospheric pressure. While it may be very hot there just isn't that much material to heat up the container.", "You have asked the key question as to why it have taken us that long to make a fusion reactor. There are currently a few different experiments going on trying to solve this problem in a few different ways. Firstly they all use a vacuum chamber. This is the best insulator and you can not really melt things if there is nothing there. To hold the lithium and hydrogen in place they can use magnets. Secondly they use highly reflective walls in the chamber so that any light produced by the fusion reaction will be reflected back instead of melting the walls. The walls are also cooled and this might be the way the energy is being harvested from the reaction. But all this is still not enough. They have to do the fusion in very tiny amounts at cool off between attempts. We have been able to do controlled fusion in reactors for quite some time. The problem is that you need a lot of energy to start a fusion so if you make the fusion very small you are unable to extract enough energy from it to recover the energy you needed to start the process. We have just been able to do this in some limited fashion. But we do not yet know how to make a proper fusion reactor from this where we get enough power in return to be worth the investment. But we are getting closer and closer." ], "score": [ 14, 3 ], "text_urls": [ [], [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2s8cui", "h2sahed", "h2sa5di" ], "text": [ "It doesn’t need to be super massive. It needs to impart a lot of energy to subatomic particles so when they crash into each other we can study the results that otherwise are not observable in nature. One way to impart a lot of energy to a particle is to accelerate it; it does so by using strong EM fields; and because our current level of technology allows us to make such strong fields only with very large equipment…we end up with a lot of massive equipment.", "The point of the LHC was to make particles go stupid fast because fast particles make energetic collisions which can spawn heavy particles If you take a fast particle and make it turn it'll bleed off some energy, the harder you make it turn the more energy it gives off. By making the LHC a giant ring, all the curves are very gentle meaning less energy is lost as waste making it easier to get stupidly fast particles (0.000001% off the speed of light) One weird quirk of subatomic particles is that short lived interesting ones are heavy. A proton comes in at 938 MeV/c^2 (it's a unit of mass, just really small) while the difficult to find Higgs Boson weighs in around 125,000 MeV/c^2 so we had to get the protons moving fast enough to have the energy to make that extra mass on impact", "The particles they are studying does not actually exist in nature in large quentities. They have extremely short lifespans so you will not find many of them by just putting your detector out in the open (they are able to test the detectors like this before turning on the collider but do not get enough data). So they actually need to make the particles they are studying. It takes a lot of energy to make matter. Not only do they need to create particles but they make particles that is then used to make even smaller particles so they need enough energy to make these as well. So the particle accelerators used for these types of experiments needs to get a huge amount of energy into tiny areas by accelerating particles to enormous speeds. And this requires huge magnets to make sure the particles stay in place and does not collide with anything. The hadron super collider is called so because they are intentionally colliding hadrons (electron, protons, etc.) into each other. And it is larger then the large hadron collider so they call it super." ], "score": [ 13, 8, 3 ], "text_urls": [ [], [], [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2sei8u", "h2sv822" ], "text": [ "When you only have a very thin layer of water, your finger ridges break through the layer of the water and directly touch the thing on the other side of it. When you have a thick layer of water, You are just moving it around.", "Water wets skin and, say marble, that means water likes to stick to your skin and the floor, which is another way of saying that water is attracted to your skin and marble. Now, when there is little moisture, water gets into your finger fringes (which gives a very high surface area) and when you put your feet down on the floor, that super thin layer of water that is now spread on that valley and hills of your feet gets in contact with the marble surface, which it also like to stick to. So the water acts as an anchor that holds your feet in place and restricts movement, and hence stickiness. \"Imagine\" thousands of billions of water molecules holding your feet in position like Captain America holding Bucky's helicopter. Now when there is more water, to the point it becomes slippery, what apparently happens is that that super thin layer of water in the previous case is no longer in contact with the marble because there is another layer of water in between so the water can't anchor to a fixed surface, the only thing it latches on to is a layer of water (whose molecules are not fixed or locked in a position like in a solid (eg- marble) because of relatively weak attractive forces). And consequently there is less friction between the layers of water than between your feet and the Cpt. America-layer, and the layer kinda slides over another layer which slides over another and so on, and hence slipperiness. Edit- Sorry for the English." ], "score": [ 12, 8 ], "text_urls": [ [], [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2seees" ], "text": [ "Every skill we have are just some connections in our brain. A neuron network that happens to solve that specific task. And when animals (including humans) are born the brain isn't blank. It already has some connections prewired so you don't have to learn those things. Comparable to a computers firmware. Humans are kind of an extreme case of how few things are prewired and how much parts of our brain are \"blank slate\". But we're still born with many things. And for the brain there isn't much difference between having the urge to breathe, having the tendency to sleep at a specific cycle, or having the urge to migrate in winter." ], "score": [ 5 ], "text_urls": [ [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2sim5h", "h2shsx7", "h2sn36r" ], "text": [ "Understeer- the car doesn’t turn enough Oversteer - the car turns too much That’s the basic way to remember it. In practice it looks like the car plowing straight forward when it understeers, and spinning out when it oversteers. You can also remember which is which by the fact that drifting is just “controlled oversteer” while looking cool. The reason for which is going to occur is down to the amount of grip the front and rear wheel have. If the front wheels lose grip before the rears do, you get understeer. If the rear wheels slide while the fronts grip, you get oversteer.", "Understeer is when your front bumper hits the guardrail. Oversteer is when your rear bumper hits the guardrail.", "You’re driving straight. You approach a turn. You turn the steering wheel the appropriate amount, but you’re going too fast. What does “too fast” mean? Either: 1. The front wheels can’t maintain traction. They’re pointed in the right direction but the car’s momentum is pushing too hard in a straight line for the front wheels to make the turn. You plow straight ahead beyond the turn. This is UNDERSTEER 2. The front wheels DO maintain traction, and begin to enter the turn. The front of the car moves in the correct direction, but the rear wheels lose traction. Momentum keeps pushing the rear of the car straight beyond the turn. Momentarily the car is pointing in the right direction. You did it! …but no. The rear of the car continues beyond where it needs to be to complete the turn. This is OVERSTEER" ], "score": [ 74, 35, 28 ], "text_urls": [ [], [], [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2skspm" ], "text": [ "It's probably how our brains are hard wired (through millions of years of evolution) do on top of what we learn (or rather on a lower level, so below) they are wired so that you see teeth bigger than yours, it automatically triggers fear response. You are hungry and smell a specyfic sent - you want to eat. and on the other wayb tou smell decaying meat for example and your body automatically triggers self cleaning program - you most likely will vomit. Because in millions of years those who did not have this automatic response and ate the decaying meat simply got food poisoning and died. [tldr] there are some patterns our brains recognise on a subconscious level and triggers semi automatic body response." ], "score": [ 5 ], "text_urls": [ [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2skmst", "h2sur4n" ], "text": [ "Muscle cramps are usually caused by dehydration and a deficiency in electrolytes... Pickle juice replaces those electrolytes quite effectively It's the same reason that expensive \"isotonic\" drinks work... And you can make your own by making normal sweet dilutable (like ribena) and adding about 1/2 TSP of salt table salt per litre", "Muscles use charged particles to help them contract and stretch. These particular particles are called “electrolytes”, and generally consist of sodium, potassium, and maybe some calcium or others. To keep your muscles healthy and well fed (especially during and after exercise), you need to have some of these, as well as some sugar (energy) and water (needed for pretty much any chemic or biological process) in your system. Pickle juice, being salty, has sodium in it. So in addition to the water you always need, the salt helps restore these electrolytes and make your muscles happier. In fact, it is technically possible to drink too much water if you aren’t also keeping your electrolyte levels high (and you’re exercising and sweating in ways that use up your existing electrolytes). Think of it like adding more water to your lemonade as you drink it, but not adding anymore lemon juice or sugar. It’s not maintaining the same ratios and therefore your whole body can start to feel dehydrated. In essence, those old Gatorade ads are right, your body needs more than just water to replenish. Gatorade itself, however, has far more sugar and far fewer electrolytes than the optimal mix. Pedialyte is a much more balanced combination of electrolytes, water, and sugar, which is what makes it so useful to recover (from parenthood, or hangovers, or muscle cramps). It’s a bit on the pricey side though. You can look for electrolyte drink powders that are more expensive than Gatorade but cheaper than Pedialyte. TL;DR “Electrolytes” are basically a bunch of fancy salts that your body/muscles need in addition to water to fully replenish." ], "score": [ 10, 3 ], "text_urls": [ [], [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2ssa7r", "h2srj3y" ], "text": [ "You know how the ocean appears blue? That's because water absorbs other colors in the spectrum. Every substance absorbs light differently. How it absorbs the light is like a signature. When light passes through the atmosphere of an exo-planet, we can compare it to the direct light of the parent star, and see how the colors have changed. That tells us what's in the planet's atmosphere .", "We can tell that water of some form is present in an exoplanet's atmosphere by analyzing the star light that passes through the atmosphere. We can tell that the water is liquid if the planet is within the goldilocks zone around its star. (Too close and the water boils off. Too far and the water freezes)" ], "score": [ 13, 5 ], "text_urls": [ [], [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2svxzt" ], "text": [ "> Can someone explain how drug tests actually detect substances. After you ingest a drug, it enters your bloodstream and circulates through your body, exerting its effects. Eventually, it ends up in the liver, which you can think of as your body's waste treatment plant. In the liver, various enzymes break down the chemical structure of whatever you took, stopping it from working and changing its form into something the body can eliminate through the urine. These changed forms are called *metabolites,* and they're what drug tests look for -- if you have a metabolite in your urine, that means that at some point you had something in you that breaks down to that metabolite, and it was probably™ the drug. > Bonus point for explaining why benzene which is a core element in benzos wouldnt appear on the test Benzene is a part of benzos, this is true. However, \"Benzo\" is short for *benzodiazepine*, and it's that other part that's important. A benzo(diazepine) has at its core a benzene ring *fused to a diazepine ring.* This fusion radically changes both how the chemical functions, and more importantly, how your liver breaks it down. It won't break it down the same way, and so it won't produce the same *metabolites*, and so the drug test won't pick it up." ], "score": [ 10 ], "text_urls": [ [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2sziuf" ], "text": [ "Most hospitals do have supply closets full of stuff. It’s not generic, because there aren’t really generics of things that aren’t drugs, but it’s usually brands that exist to supply institutions at low price. Hospitals have shampoo, razors, nail files, toothbrushes and toothpaste, tampons, and so on. Usually you don’t pay for them, they’re included in your bill—some of the few things the hospital can’t bill you for!" ], "score": [ 5 ], "text_urls": [ [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2swwg2", "h2sxle3" ], "text": [ "If you take a big cloud of stuff out in space gravity will tend to pull all of it towards the gravitational center of the mass, which will become spherical as everything pulls on everything. All this stuff tends to be moving in different directions, but as gravity pulls everything together these movements in different directions are cancelled out by each other. Now this cancelling out won't be perfect, because the initial movements won't be perfectly equal in all directions, so what's left over is some level of residual spin to the sphere. The spin causes a bulge to appear along the \"equator\" of the spinning sphere, creating a general plane with a bunch of stuff in it, and it will start the process over on a smaller scale. So a galaxy tends to have a spherical bulge at the galactic core, followed by a galactic plane full of stars. Stars tend to be a sphere with a bulge along a solar plane which are full of planets or asteroids. Planets tend to be a sphere with a bulge along it's planetary plane that tends to create moons or rings.", "Essentially the objects in orbit (particles in the ring/stars in the galaxies) are gravitationally attracted to the planet/black hole. This is a type of centripetal force. You can think of gravity as something that keeps the particles from flying off into space or that holds them together (like a string attaching a basketball (at what would be its equator) to a golf ball). If you start spinning the basketball very quickly, the golf ball will be pulled along with the rotating basketball and will follow along in a plane which would be along the equator of the basketball as it spins. Think about it, if you were spinning the basketball around it’s axis with the golf ball attached to its equator, the golf ball wouldn’t go from North Pole to South Pole to North Pole, it would follow where it was attached and move in the same direction as the point it was attached to." ], "score": [ 11, 3 ], "text_urls": [ [], [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2t1iku" ], "text": [ "I think the exact question is \"how do displays work?\" The most common type of display, LCD, are made of multiple layer. A backlight, a color filter, and the LC. The backlight is what controls the brightness of the display. The color filter, filters the backlight's light into the three primary colors, red green and blue. The LC then filters the RGB colors to turn them into different colors. The LC is short of Liquid Crystals. It's bascially a gell with tiny plates inside. The plates can rotate freely in the gell and can be moved using electricity. When you align all the plates, they work like a window blind. They can block or allow light through them. Using this, the LC would block or allow RGB light passing through to make different colors. Have millions of these multicolored pixel on panel and you've got a display. Repeat these steps 60 times a second and you've got a video." ], "score": [ 5 ], "text_urls": [ [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2t17t6" ], "text": [ "A lot of clinical depression tends to be linked to chemical problems in the brains regulation of dopamine. Dopamine is the chemical that assists in the part of the brain that deals with goal making and the feeling of accomplishment from completing goals. This tends to cause a general malaise where nothing feels worth doing. This in turn tends to cause feelings of worthlessness and a general lack of fulfillment in life. Simple sadness isn't the best description of the affliction, although the lack of fulfillment does give a lower baseline happiness level." ], "score": [ 9 ], "text_urls": [ [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2sz99p" ], "text": [ "Brood parasites like cuckoos and cowbirds don’t think they’re the species that raised them - they instinctively harass their nestmates and even their “parent” until it’s time to leave. Once they mature, they do the same mating song and dance that all songbirds do. Nobody ever teaches a cardinal what a cardinal’s mating song sounds like or what a nest looks like, it’s built in behavior. The same is true for lazy brood parasite birds." ], "score": [ 12 ], "text_urls": [ [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2t6xo9" ], "text": [ "I wish clothiers would pre shrink the materials but alas not all do. The reason is the weave of the material, if you look close you will see lines of threads all running vertically these then start to shrink which is why in my case my belly is sometimes exposed in what was a new and fitting t-shirt before it went in the wash." ], "score": [ 6 ], "text_urls": [ [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2tnopg", "h2u0p9m", "h2to2z9", "h2tqi9r" ], "text": [ "Usually they’ll have radiators, which are not like the radiators in your house. On Earth it’s a lot more straightforward to get rid of heat. You just push it somewhere else. There’s stuff everywhere, so you can give that heat to other stuff. That’s conduction. In space there isn’t a lot of stuff, so you usually have to get rid of it through radiation instead of conduction. Anything with any temperature (so everything) gives off some light. Most of this is infrared, so we can’t actually see it, but everything is constantly shooting out little bits of light. Some materials are better at giving off infrared than others and so usually you’ll just make a big surface covered in one of those materials. You’ll basically just transfer heat over to the radiator using normal conduction, and then let the radiator shoot it off into space as infrared.", "By having very low power levels and a large amount of radiators \"Fission reactors\" used in space aren't close to the ones on Earth. Radioisotope Thermal Generators (RTGs) have a big block of Pu-238 that just sits there being hot. There isn't an ongoing chain reaction like in a nuclear reactor, its just relying on the spontaneous decay of Pu-238 atoms. If you look at [the RTG from the Cassini mission]( URL_0 ) you'll see that its a big cylinder with a bunch of fins around it. These fins serve to radiate the heat and produce the cold side needed for the thermoelectric generators to get 300 Watts of electricity out of the 4000 Watts of heat. Some of them are equipped with cooling tubes as well which can be pumped to external radiators like the ones on the recent mars rovers The casing of the RTG is meant to run hot to deal with the literally red hot plutonium hunk in its core, but we're pretty good at insulating heat and more heat doesn't result in faster decay here so the core won't run away, it'll just get up to a high temperature and sit there for decades", "There are three methods of heat transferring. Conduction, where the heat is conducted through a solid material, like when the handle of a metal spoon in a hit dish starts to heat up. Convection, where molecules physically move carrying the heat energy with them, this is like the wind and air currents in the atmosphere (or cycling of hot and cold water). And radiation, where the extra energy is emitted from the item as radiation. This is what happens when you see a piece of metal start to glow red-hot. It is so hot that the heat turns into light radiating off of the item. But, this can also happen at cooler temperatures, where the item doesn’t start to glow, but is still putting off invisible radiation (like infrared radiation) that we can’t see with our eyes. That is how things are cooled in space, there are large, flat panels that the heat is brought to that then dump the heat back out into space through this kind of radiation.", "Option 1: use it to boost the temperature of your propellant. The propellant absorbs the heat and you eject it out the back. Option 2: smaller power reactor with huge radiators." ], "score": [ 27, 7, 5, 4 ], "text_urls": [ [], [ "https://upload.wikimedia.org/wikipedia/commons/thumb/b/bd/Cassini%27s_RTG.jpg/517px-Cassini%27s_RTG.jpg" ], [], [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2tq3in", "h2tr60e" ], "text": [ "Alcohol also has calories. 7 calories per gram of alcohol when it's metabolized. It's basically alcohol, carbs, fat, and protein that you get calories from.", "Ethanol specifically is a two carbon alcohol. Long story short, it breaks down into energy the same way fat does, it goes into the Krebs cycle. It's not a clean process though and the process is kinda sorta toxic." ], "score": [ 3, 3 ], "text_urls": [ [], [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2ttt94" ], "text": [ "Fluorescent lights, because of how they work, require something called a *ballast* to function. A ballast is an electronic component that acts to limit the amount of current flowing through a circuit. Without this, a fluorescent light would draw more and more current in an exponential process, quickly destroying itself. The older type of ballast, a *magnetic ballast*, is more likely to buzz, and buzz louder, as the flow of current through the device changes." ], "score": [ 12 ], "text_urls": [ [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2tvxtm" ], "text": [ "Direct download would be a link that points exactly to the item you're trying to download. It could be the same as the item that a download button on another website gives or leads to, but it isn't necessarily the same as the download button itself (which could be a redirect *to* a direct download). Generally speaking, a direct download link won't send your browser away to another website, it'll just initiate the download of the item it links to. So if a link goes to another website (that, in your example, has a download button) it is *not* a direct download link. The whole purpose of the \"direct\" portion is that when you click that link, your download begins." ], "score": [ 5 ], "text_urls": [ [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2tx5s6", "h2tx2nx", "h2ty66o", "h2u88od" ], "text": [ "As someone that lives in the Eastern U.S., what are you talking about? The Appalachian Mountains run through half of the Eastern U.S. There are wetlands in about 1/3 of the Eastern U.S. as well. The Great Lakes are in the Eastern U.S also.", "The North American Continent is very slowly moving westward because of continental drift. That caused the Rocky mountains to form, and it's those mountains that charge the weather from sunny and warm at the coast, to rain forests, to tall frozen mountains, to plateaus and deserts, and then eventually to the open plains. The east has the Appalachian Mountains which were formed in roughly the same way but they have been eroded away by millions of years of erosion.", "It's not. I'm guessing you just haven't traveled much, because there are some incredibly diverse ecosystems from Maine to Florida and out to the Mississippi. Just gotta get out there and see it. Unless you're just talking about the Rocky Mountains, in which case it looks different than anything \"back east\" because the Rocky Mountains are not \"back east\"", "Most of what you are talking about exists because of more active plate tectonics and vulcanism. - Rocky mountains have formed recently enough to be tall and perpetually snowy. - The cascades are still volcanic. Earlier vulcanism has by now slowly cooled to form the Sierra batholith (aka Yosemite national park), while active vulcanism exists in Oregon and Washington. - The Colorado plateau has been uplifted in the last few tens of million years, but enough time hasn't passed for it to erode away fully. The plateau does not expose volcanic granite, but red, yellow and brown sandstone because it was an ancient submerged land. - Finally, there is the father of all volcanoes-Yellowstone. It is a giant hotspot that has been flattening land like a flame under a bed of frozen wax as the North American continent drift over it. The path followed by the hotspot is now the Snake river valley. The east coast is more, er, stabilized. New York City is on very stable bedrock---the subway is as big as it is partially because of that. The Appalachian mountains are much older than the Rockies. The Canadian Shield has been stripped bare with erosion so that only the hardest rock remains. The West coast is what the East coast once was." ], "score": [ 10, 8, 7, 6 ], "text_urls": [ [], [], [], [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2tzwx0" ], "text": [ "I'm sure you've heard it said that the mitochondria is the powerhouse of the cell. As it turns out, the mitochondria is also the *furnace* of the cell: the same process that gives us the chemical energy to function also releases *thermal* energy -- our body heat. Reptiles and other cold-blooded critters simply don't burn fuel as quickly as humans do, so they can't keep their bodies at the optimal temperature without basking in the sun." ], "score": [ 4 ], "text_urls": [ [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2uaiau", "h2u07qo", "h2tytno", "h2u34vj", "h2ue8ta" ], "text": [ "It is in theory possible for something to remain in motion forever. In fact, this is a natural consequence of Newton's first law: objects in motion will stay in motion unless acted on by an outside force. When people say that perpetual motion machines aren't possible, what they *really* mean is that you can't create a perpetual motion machine *that can do anything useful*; because anything useful you try to do with it requires you to extract energy from the system, which will eventually slow it down until it stops. If it were possible to create a perfect vacuum, place an object in that vacuum that wasn't subjected to any other forces, and set it spinning; then that object would remain spinning forever. It should be noted though that a perfect vacuum is impossible for any *practical* application. Space itself isn't a perfect vacuum: at its most empty it still has a density of something like one atom per cubic centimeter. And there isn't a location you can find anywhere that doesn't have *some* kind of force acting on it, however weakly. So although it is theoretically possible it is by any *practical* definition impossible (and, as others have noted, the Earth is in fact slowing down... just very slowly).", "To be like perpetual motion the earth would need to spin at a constant rate since it first formed, however we know this not to be true. We have geological evidence the earth spin has slowed based on the length of prehistoric days. We can also still detect fluctuations in the earth's spin, sometimes human activity will slow it down but unnoticeable except by scientific instruments. Will the earth ever stop spinning? Theoretically yeah, without something to increase its speed. Will it happen on a time scale that matters? Probably not. Humans will likely either be extinct or have abandoned the planet before then, earth may even be engulfed by the expansion of the sun into a Red Giant before then.", "Innertia. As the earth spins, theres nothing its rubbing against to cause friction which would steal its innertia. In a machine, parts will touch and create friction which steals the motion.", "The earth is slowing down and will eventually become tidally locked to the moon just as the moon is currently tidally locked to the earth. Tidally locked is why the same side of the moon is always facing the earth. Very few humans have ever actually seen the back side of the moon.", "Perpetual motion is possible. It's actually a pretty fundamental law of physics that an object in motion will stay in motion until some force changes that. On Earth that's usually friction, but in space there might effectively be nothing nearby to stop an object drifting endlessly. The Earth's spin on its axis and orbit around the Sun are in fact changing, due to friction, tidal forces, and the Sun losing mass. But they are massive enough and it happens over long enough timescales to not be important. When people talk about a perpetual motion machine, they usually mean a machine that both exhibits perpetual motion *and* is able to extract some useful energy from that system (usually to power some other device). As you can imagine, once you start taking energy out of the system, the motion is longer perpetual. You can't just magically get energy from nowhere. And that's assuming you can even build a perfectly efficient machine in the first place which doesn't lose waste energy anywhere. The reality of engineering is you will always lose some energy to heat, sound, light etc." ], "score": [ 42, 21, 10, 10, 6 ], "text_urls": [ [], [], [], [], [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2ul8v3" ], "text": [ "Here's a paper about how much eye size varies. URL_0 Answer is: very little in the direction that matters to focal length. As heads get bigger, eyes get wider, but not deeper." ], "score": [ 5 ], "text_urls": [ [ "https://pubmed.ncbi.nlm.nih.gov/25431659/" ] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2u773f", "h2u61qw" ], "text": [ "Rim brakes are cheap, simple, easy to install, easy to maintain and provide effective braking under most conditions provided you’re not doing a lot of heavy braking under wet and dirty conditions. Disc brakes can provide more effective braking, particularly in wet conditions or if mud/whatever is getting kicked up. You won’t fuck up your rims because some grit got lodged in the pad or from having to brake too hard down hills. OTOH they’re more expensive, put much larger forces on your forks so you need a bike that’s designed to accept them, maintenance is more expensive and difficult, and they can be very sensitive to correct alignment. Disc brakes are probably better under many metrics, but for a lot of people the other trade offs aren’t worth it, but for others they are.", "They don't. Not many people into road cycling do anymore at least. If they recommend them it's because they are lighter and less fussy than disc brakes, which can rub and squeal." ], "score": [ 7, 4 ], "text_urls": [ [], [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2u6hhh", "h2u6jp1", "h2vp889", "h2u7tij" ], "text": [ "Put simply, the wash sale rule prohibits an investor from claiming a capital loss for tax purposes if they repurchase the stock or security within 30 days.1 Specifically, the IRS deems a transaction a wash sale if the investor does the following 30 days before or after a sale: 1. Purchases the same investment 2. Purchases a substantially similar investment 3. Enters into a contract to buy a similar investment 4. Acquires a similar stock for an IRA or Roth IRA An Example Imagine an investor unfortunate enough to purchase Lucent Technology stock when it was trading upwards of $70 per share. Over subsequent years before the firm disappeared through mergers and acquisitions, that investor watched accounting scandals, financial trouble, and sales meltdowns wipe the share price down to $1.3 Ever the enterprising baron, our investor realizes that if they sell their shares, they can report a capital loss and lower their tax burden. The problem? They believe that Lucent, or the firm that ultimately owns it, will rise from the ashes and return some of the market value which it has lost. Suddenly, our investor gets a brilliant idea. During the last week of December, they call their broker with instructions to sell their shares in the telecom equipment supplier, locking in the capital loss. Three weeks later, during the first half of January, they ask their broker to repurchase those shares of Lucent. All is well in the world; they locked in the capital loss while holding onto the shares. Seems ingenious, right? The wash sale rule, as you remember, does not allow an investor to claim a capital loss if they repurchase the investment within 30 days. In other words, unless the investor waits until the 30-day period has elapsed, they will not be able to write the off the loss. There are ways around this, but let us assume the guy in the article didn't do that. He sells his shares down at $1 in December, buys them back in the next year at nearly the same price, and the stock goes back up. His 2019 taxes say he lost $5,000,000 and he got an $800,000 tax break, but in 2020, they went up to a total of $5,045,000 ($45,000 profit), but he gets penalized for the wash sale, and has to pay back the $800,000", "Basically people try to game the system by selling stock at a loss and then buying the same stock back the next day. You have to wait 31 days or be penalized. You could potentially invalidate the tax loss from your original sale by buying the new stock see? Like you don’t lose anything tax wise after fucking up on an investment. It does not apply to day traders, as they do not have souls and pay taxes directly to satan.", "I found the article. So he was day trading stocks, traded $45 million worth over the year. Probably GME stock most likely. Lots of new traders this year that don't know the rules.", "When calculating how much you need to pay in taxes, you use your *net* earnings. This means you subtract your losses from your gains and owe taxes on what's left. So let's say I buy stock A, the price goes up and I sell it and end up making $1000. And I also buy stock B, but the price goes down before I sell it, and I end up losing $400. I've made $1000 and lost $400, so my net earnings are $600, and I pay taxes based on that $600 figure. However, the value of stock doesn't count for taxes until you actually sell it. If the price of stock B went down, but I didn't sell it yet, then it wouldn't affect my taxes, and I would pay based just on my stock A earnings, $1000. Normally, this is fine. Maybe the price of stock B will go up before I sell it, or if I sell it at a loss next year I can use that loss to reduce next year's taxes. The wash rule prevents people from gaming the system. So, take the situation where I buy stock A, sell it after the price goes up, make $1000. I buy stock B, the price goes down, I don't sell. At this point, I posses $1000 and stock B. So I get taxed on the $1000 and stock B doesn't affect anything. But what if I were to sell stock B, but then I buy it right back? I end up possessing the $1000 and stock B, just like before. Your situation hasn't really changed. But on paper, I lost $400 from selling stock B, so I get to claim that I only earned $600 net when I pay my taxes. The IRS doesn't like this, so the IRS made a rule. If you sell stock at a loss, but buy it back at basically the same price, the IRS will pretend that sale didn't happen. Because basically, it didn't. You'll still get to reduce your taxes when you eventually sell the stock at a loss, but only once you sell it for real. So, what probably happened to the person in the article, was that they made some trades where they made a lot of money, but also some trades where they lost a lot of money, so they only made $45k in net profit. However, some of those trades where they lost a lot of money, they quickly undid them. So, they didn't really lose the money. So, really they earned a lot of money this year, and are paying taxes on that large net profit. They also have some bad stock, that when they do sell for real, will reduce their taxes by a lot. So basically, they're being kinda misleading in the article. They claim they didn't make much money, but only if they count stock they haven't sold, as if they had sold it." ], "score": [ 13, 7, 3, 3 ], "text_urls": [ [], [], [], [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2ucvkp", "h2ufy1i" ], "text": [ "Heat overloads the nerve network so effectively that the urge to scratch is abolished for hours. Usually you stimulate the nerves through scratching, although that isn't as intense and is more localized than hot water all over your skin. The reason scratching is bad for you is because the friction tears your skin and can damage it more. Hot water has the same effect but no tear damage.", "Most nerves can only communicate one type of sensation at a time. That's why applying pressure to a wound dulls pain, or, in this case, intense heat dulls itching. That said, it's not a great idea, as the heat will open the pores in your skin and get the oils that cause the itch deeper in/spread it around." ], "score": [ 10, 4 ], "text_urls": [ [], [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2u8eyz" ], "text": [ "Because there's suction due to a pressure difference. When you open the door, room air mixes with the cold air in the fridge. After closing the door, the sealed air in the fridge is warmer than the intended fridge temperature. The fridge then cools the air. Colder air takes up less volume than warmer air. The air trapped in the fridge gets chilled and tries to lose volume. What volume it can't shrink lowers the air pressure instead. With lower pressure inside and higher pressure outside the door trying to get in, there's now a suction force pushing the door closed! That's what you're pulling against the next time you open the door." ], "score": [ 19 ], "text_urls": [ [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2ufjdf" ], "text": [ "The caramel color is actually made by heating carbohydrates, and that is exactly how most syrups are made. Eli3, because they have some syrup in them." ], "score": [ 8 ], "text_urls": [ [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2u9niq" ], "text": [ "99% of the time it's just another person, or a fund manager trying to acquire more of the stock for the fund, or an investment branch of a bank trying to acquire more of the stock for its investments, or a company trying to increase its ownership of another company. Sometimes it's the issuing company itself. A stock = a portion of ownership in the company, so if they are able to take back some of that it helps them maintain control over ... themselves. Or sell it at a later point when the value goes up and they can get good money on it again." ], "score": [ 4 ], "text_urls": [ [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2uqc89", "h2ubq8l", "h2uvs2o", "h2uktoa", "h2v88c8", "h2vrvin", "h2vixci", "h2unsei", "h2vmf9n", "h2vhc8m" ], "text": [ "Swelling results from capillary leakage, which itself results from the release of inflammatory compounds at the site of injury. The fluid can become what's called organized, in which proteins in the fluid, like fibrin, accumulate, and this can make the swelling permanent to some degree. Does the swelling serve any purpose? The capillary leakage also lets white blood cells into the damaged area, and these control infection and gobble up debris (by Pac Man-type cells called macrophages) from the injury, so I think the answer is yes. But getting rid of the swelling within a week is a good idea, as the infection control and gobbling up of debris is done by that time as well.", "The swelling, inflammation, is what hurts. It's what hurts with a headache, or a sprain. Ice slows down and reverses the inflammation, hopefully to where you can tolerate it, so they can have a good look at what's wrong without you screaming. You also can't set a leg/arm while it's swollen.", "Swelling is the bodies reaction to increase bloodflow to the affected area to help with healing. Evolution is not perfect and usually the swelling can be too much and cause additional damage or interfere with applying modern medicine. We reduce the swelling to avoid additional damage and inspect // apply proper healing techniques.", "Swelling is to prevent further injury. But the body/nature/evolution didn't plan for modern medicine, so the swelling gets in the way of treatment.", "When the body gets injured, it wants to do two things: minimise the risk of infection, and make healing happen as fast as possible. Both of those things benefit from increased local blood flow. Increased local blood flow also produces swelling as a side effect. If the injury is small, this is no problem, and the process works well enough for, say, a small cut or bruise. The problem is if the injury is large, the swelling that results from the increased blood flow can have bad effects on the surrounding uninjured parts of the body, by stretching tissue, putting pressure on nerves and other blood vessels and things like that. The body's internal mechanisms are not smart enough to be able to determine when a good response (more blood flow) can have harmful side effects (too much swelling).", "Short and stupid. Swelling is a good idea if you are a dumb creature out in the wild with no access to modern medicine. It allows increased blood flow and white blood cells to help with the injury, it makes the area hurt so you are less likely to continue to damage it, and it makes it somewhat immobile to - again - prevent you from doing something stupid to exacerbate. There is a theme here. That theme is its advantageous to assume the operator of the body is dumb and unless it hurts it will continue to do dumb things. Considering people have caused injuries by trying to do backflips off beer kegs, it may have a point. Swelling is also a bad idea as, well, it's what causes a lot of the pain and it has a chance to cause a more lasting impact if left unchecked for too long. Joints can freeze if not moved and swelling can become a permanent state. We.now have medicine. We have casts and splints that can immobilize better than making the joint too large. We have surgeries that can repair slow healing injuries. We crutches and wheelchairs and all sorts of props to keep us off an injury and we have a lot of professionals who have come up with exercises and practices to speed up recovery. So now that we have largely removed the need for the body to limit your stupidity, there is less need for this swelling to be there making your life miserable and potentially leaving a permanent reminder of why trying to impress that blonde in the halter top by shouting \"look what I can do!\" Before drunkenly climbing Mt. Budweiser is a bad idea.", "Swelling is there so you can keep hunting right after the injury. We don’t hunt anymore so it’s overkill, so we try to reduce the damage that inflammation does.", "Apparently it's is, it won't help. But definitely check this out: New studies show that it's the *inflammation that kickstarts the healing process*; the old RICE is now said to be 180 degrees wrong. You should be able to find multiple links to stories about this. More of the human \"if it sounds good it must be right stuff\" maybe.", "Also if they want to operate, they need the swelling to go down otherwise when they want to bring the skin back together they won’t be able to. Worst case scenario they’ll have to put metal rods (ex fix) to help", "I think this is a really good question. It always stuck me odd how many measures we take to suppress our body’s natural evolutionary reactions. Like, we have swelling and fevers for a reason. We evolved these traits because they helped us survive. I know there are good reasons we fight against them, but it still seems weird to me." ], "score": [ 796, 262, 50, 23, 14, 7, 5, 4, 3, 3 ], "text_urls": [ [], [], [], [], [], [], [], [], [], [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2ugm60", "h2vqwss" ], "text": [ "You know how you can make a picture brighter after you take it? It's basically that, but with sound. You're just changing the data so that it represents a louder version of the same sound (*/brighter version of the same picture*) The picture doesn't actually have inherent brightness until you display it on a screen. The sound doesn't actually have inherent volume until you play it with speakers.", "* You can't hear digital music. * It has to be converted back to analog first. * Your computer has something called a DAC in it that converts from digital to analog. * This circuit reads the digital data and based on the numbers creates a voltage signal. * So when you turn the gain up on the computer, it's changing the data to have a higher value so when that data is fed to the DAC, the result is a higher voltage signal than you would have gotten before. > Is it really adding \"gain,\" or is it actually just increasing volume? * In this case it's doing both since increasing the gain of the digital audio signal results in a higher volume when converted to analog and pushed through speakers. * A note about gain: * The concept of gain has to do with signals, any signals. * Gain just means some relative change in the level of a signal. * Volume in the context of sound more or less means the intensity of the sound level. * It's not a technical term by any means and is not every really used in the professional audio world. * However most consumer devices use it as sort of a nickname for the gain of a sound system especially one inside your TV." ], "score": [ 4, 3 ], "text_urls": [ [], [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2unfrb", "h2un7j1" ], "text": [ "The odds are actually really high, basically 100% if you give it enough time. Lots of moons are tidally locked. It’s not a random thing where the moon just happens to rotate as fast as it orbits, it was something that happened over millions of years and tends to happen to basically any objects in orbits. Gravity tends to drop off really quickly with distance though, so it happens very quickly (in astronomical terms) with moons, which are fairly close, compared to planets and suns that are much further apart. Though Mercury does have a synced orbit to the sun.", "Tidal locking is a natural state that all orbiting bodies will eventually fall into, given enough time. What happens is that the gravity of one body pulls harder on the near side of its partner than the far side--this causes an uneven force which stretches the material of the partner body along the axis between them. This is what causes sea tides here on Earth, the Moon and Sun's gravity both have this tidal effect. So how does this inevitably lead to tidal locking? If the partner body is rotating at a different rate than its orbital period, the bulge caused by the tide gets pulled away from the direct axis between the two bodies. That bulge then gets pulled on by gravity in such a way it tends to move the partner's rotation speed to match its orbital period. This process takes a very long time, but once it's finished the system is stable and the tidally locked body will stay that way forever. So, does this mean the Earth will eventually become tidally locked to the moon? In theory, yes. In practice, the Earth is so much more massive than the Moon that the time taken for it to get tidally locked to it will comfortably exceed the remaining lifetime of the Sun." ], "score": [ 10, 7 ], "text_urls": [ [], [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2vem5w" ], "text": [ "When you say 'dirt' =, what youre referring to is a mix of lots of different types of soils. If the soil has a lot of clay, it turns into mud. The reason is that clay is 'waterproof' so the water doesnt go inside the dirt, it just sticks to it, making it very slippery and easy to move aka mud. If the dirt is made of say peat, or chalk, or other minerals, it actually absorbs the water like a sponge, meaning it doesnt get as slippery or easy to move. The other thing is drainage - if the dirt is loose and deep, the water drains to the bottom very quickly, meaning there is less at the top to make it slippery and muddy. If drainage is poor, the water just sits there and creates mud." ], "score": [ 40 ], "text_urls": [ [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2vjgm0", "h2vjjaa", "h2vifq0", "h2vibm8" ], "text": [ "You have eyes. Two of them! When you look at stuff, we call you the subject, and we call the stuff the object. Now imagine yourself looking into a mirror. If you do it right, congrats! You are seeing yourself. You are both the person looking (subject) and the stuff being looked at (object). Reflexive verbs are reflective in the same way as the mirror. It reflects the action (looking, or whatever the verb is) back onto the subject. Just like you can look at yourself, you can wash yourself, get yourself out of bed, sit yourself down, and so on. Remember that old prayer: Now I lay me down to sleep? That's the same thing!", "I can only speak for German but i'll try: In the German language, there are certain verbs that can only be used to describe doing something AND doing that thing to oneself *at the same time.* These are called **true reflexive** verbs. An example: \"Ich *konzentriere mich* auf meine Arbeit.\" (I am concentrating/focusing on my work). A subject can't 'concentrate' someone/something else, only itself. (Even though the word 'concentrate' in german as in many other languages can have the second meaning of 'pool together' / 'mass', then it isn't a reflexive verb). There are other verbs that can be reflexive by adding a reflexive pronoun. These are **reflexive verbs**. Example: \\- \"Sich waschen\": Ich wasche mich. Du wäschst dich. Sie waschen sich. (To clean oneself, i clean myself, you clean yourself, they clean themselves). It is only reflexive if the reflexive pronoun is added. This means that you can use the verb 'waschen' (to wash/clean) reflexively, but you can also use it non-reflexingly, for example if you say that you are washing a shirt (\"Ich wasche das T-Shirt\"). Then there are verbs that can't be used reflexively. Examples be 'Rennen' (to run), or \"Schlafen\" (to sleep). ELI5: a verb is a reflexive verb if you can use it to describe ***doing something while at the same time doing it to yourself***. You can wash yourself, you can dress yourself, you can picture yourself but you can't, for example walk yourself or sleep yourself.", "With most verbs, you have a subject (the thing doing the verb) and an object (the thing the verb is being done to). A verb is reflexive when the subject and object are the same thing, when the subject does the verb to itself.", "A reflexive verb is an action the subject took. For example in French (should be similar in Spanish) if you want to say “I wash myself” you would say je (I) me (myself) lave (wash) “je me lave.” For reflexive verbs you put the reflexive pronoun immediately behind the subject." ], "score": [ 41, 16, 12, 4 ], "text_urls": [ [], [], [], [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2vk60s" ], "text": [ "The basic one, until we started polluting it. Long story short, unless it has any reason not to be, water is clean. Stagnant water (lakes, pond, etc...) accumulate a lot of unclean wildlife and thus disease. But pretty much all moving water (rivers) are usually very clean naturally. The only things you really need to be careful about are small insects and other impurities like leaves etc... which can easily be removed with basic filtration. purification became a necessity when we started to dump chemicals in water. Otherwise, filtration was mostly enough." ], "score": [ 15 ], "text_urls": [ [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2vki2m", "h2vkqxk", "h2vssvj", "h2w5wf2", "h2vkgil" ], "text": [ "It can rain more in other areas, or the weather may be so hot that water doesn't condense into rain as easily, so more water gets \"stuck\" as clouds.", "Most of the water cycle is evaporation from large bodies of water like ocean, transport of the water vapor by the wind, rain, flow into the ground and back to the ocean. In drought conditions you don't get the rain for various reasons so the water keeps running towards the oceans but there's nothing to replenish it. So, the rain that would have happened is either occurring before it gets to the drought location or is being carried past the drought locations.", "When there are no plants to hold the water from sinking into the dirt below like in a desert, it is difficult to extract it for storage and use during the dry time. This is part of the water cycle called \"transpiration\" like the plant holding the moisture and slowly sweating it out. Also during the precipitation part of the water cycle, no plants to help decrease the barometric pressure to cause the clouds to rain in certain areas.", "Lack of rain can be caused by several things. First let’s talk about temperature. The hotter it is the more moisture the atmosphere can support. We call the maximum amount the atmosphere can support at a given temperature it’s saturation vapor pressure. When you look at relative humidity you are looking at the ratio of actual vapor pressure (think how much water there currently is in the atmosphere) to saturation vapor pressure. Basically if you see 50% relative humidity the atmosphere is at half of the maximum amount it can support. Why is this important. Well once the relative humidity is 100% any additional water vapor turns into liquid water. That’s a cloud. So what does this have to do with temperature? As temperature goes up the maximum amount of water vapor the atmosphere can support goes up meaning that it takes more actual water in the atmosphere to form a cloud, or rain. Hot sunny days also increase evaporation from the soil so all of the surface moisture plants use evaporates away. If there is not enough water in the soil to allow the atmosphere to form clouds and then rain then that water just sits there until there is enough which means it could be carried off by the wind to another location. But that’s not all. The whole temperature humidity cloud thing is typically fairly small scale. Droughts often affect large areas. On a larger scale we have to look at pressure systems so we have to look at where high and low pressure are. We can also associate these systems with rain. High pressure systems have bright sunny days. Low pressure systems rain. If you’re teetering on the edge of a drought being stuck under a high pressure system is a bad thing. Well typically these systems are fairly transient, but there can be these events called blocking highs. Basically it’s a weather pattern caused by the position of jet stream that allows a high to just sit in place for an extended period of time. Again not a good thing with a drought. Finally let’s talk about the rain. A drought just means some threshold of below normal rain over an extended period of time. That means one rainstorm typically doesn’t get you out of a drought. The ground can only hold so much depending on soil type if it rains too much for the ground to handle the water will just run to the nearest stream and then be of no use to the plants. A drought buster isn’t a single big storm, but days or weeks of fairly constant rain. There’s even more to this honestly, but it would take a few school style lectures to go into all of the nuances.", "In a dry area, evaporation can be close to non-existing. And if the winds do their part in moving large masses of air, any potential for building a rain cloud may be transported away. If we add high temperatures and/or high absorbtion in the ground, the conditions for a draught will be good." ], "score": [ 44, 11, 4, 4, 3 ], "text_urls": [ [], [], [], [], [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2vls85", "h2vmg9c", "h2vpbzm", "h2vqcx1", "h2vtuk8", "h2w2dib" ], "text": [ "Free will and consciousness and two of the unsolved problems in Biology. Unfortunately, there's no answer. Not yet, anyway.", "Depends on your definition of \"Free Will\" we might not even have it. Like a complex robot we react to internal and external stimuli to quench a need (mostly by internal stimuli activated) You get thirsty (because of low water content in your blood), therefore your brain figures out what you like to drink (chemical receptors in your tongue figured that out) and where to get it the most energy efficient route it remembers (also it tries to remember stuff energy efficiently). That's all there is to free will, just too many variables to make it feel like it's \"free\"", "Free will isn't a brain thing, it's a mind thing. Software, not hardware. As a result, it's not caused by some hardware feature of the brain we evolved. It's an idea we thought up.", "We don't have free will, if having free will means we aren't just very complicated robots. There's no evidence that we are anything more than that. Some philosophers (most famously, Hume, Dan Dennett, and Harry Frankfurt) argue that a proper conception of free will isn't incompatible with us being robots. They think having free will is a matter of being free of external constraints (the obvious ones, like a gun pointed to your head; not laws of physics), or being capable of rational decision making, or something along those lines. If you agree with those philosophers, then your first question either has an obvious answer having nothing to do with biology (\"no gun pointed to my head, I'm not handcuffed, ...\") or is not answerable yet (\"what makes us capable of rational decision making?\" Well we have brains, but nobody knows how exactly brains do it. Not yet). Which is to say, nobody knows the answer to your second question. And, I think it's worth clarifying, it's not just because we don't know why the brain is conscious. It's that we don't know how the simple things each neuron does add up to complex behavior. Consider AlphaGo. I don't think anyone suggested it's conscious. All the same, we don't know how its low level properties (what the neutral nets do after massive training) are related to its high level ability of playing Go. If we knew, it would be possible to build a powerful Go playing AI directly, without training. But we don't.", "I am not going to talk about free will as far as it goes to humans as robots and running a program. This is philosophy, and overall while a fun, a very pointless path of thinking when trying to understand consciousness. The question I think you are asking is why do we experience consciousness, and decision making. Let me try to answer that. First, we are a lot less in the driver seat of our bodies and minds than we think. We can't control most of our body functions. From our digestion to our heartrate the part of our minds that we often think as ourselves has very little say. We might be able to do things to then influence our heartrate, but we can't directly tell our heart what to do. We also don't have control of our thoughts. We need psychologists to teach us how to trick our thinking into doing what we want. It's like heartrate, most of our thinking is done out of our control by the subconscious . Even more it's done without us knowing about it. In many experiments on people with specific brain damage it has been shown that when facing a decision, we will make up our minds before we ever know that we do. After our subconscious has made a decision, we will then rationalize the decision. I often like to tell people we are like Maggie driving the fake steering wheel in the opening of the Simpsons. So the real question becomes why do we think we have free will when really the part that we call our conscious self does so little decision making? Here we don't have answers but I am going to give some of our guesses. It makes us better social animals. It lets us interact with others, by creating this idea of self that feels like it's in charge. It also may be a good way to solve some specific problems like math that face us. Interesting enough the subconscious is also way better than us at solving other problems, this is why we always get those answers on the toilet or in the shower, when it's done doing it's work, and finally tells us what the answer is. So TLDR, even past the whole human robot thing, we don't really have free will, just an illusion of self created by a much larger mind than what we consider conscious self.", "Biologically, there is no evidence of free will. It cannot be pin-pointed or located. Thinking and making decisions, yes, we understand where that occurs, but there is not evidence that free will plays a role in this or exists at all." ], "score": [ 52, 27, 7, 4, 4, 3 ], "text_urls": [ [], [], [], [], [], [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2vozct" ], "text": [ "Speed has little to do with power. More winding wires inside the motor give more torque at a given speed and current, but take higher voltage to drive that current. Special winding arrangements, like the motors you excluded, have more complex effects." ], "score": [ 3 ], "text_urls": [ [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2vpae6", "h2vqnmk" ], "text": [ "Adrenaline is released mainly through the activation of nerves connected to the adrenal glands, which trigger the secretion of adrenaline and thus increase the levels of adrenaline in the blood. This process happens relatively quickly, within 2 to 3 minutes of the stressful event being encountered. Sometimes the body will release the hormone when it is under stress but not facing real danger.", "Part of the process is connected to emotions. Feeling strong fear or anger? Release some adrenaline. Now how does the body/mind know when to feel anger or fear? That is a much harder question." ], "score": [ 9, 6 ], "text_urls": [ [], [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2vpntc", "h2vpqby", "h2vs232", "h2vprkk" ], "text": [ "Email business models, like telephone ones before them, built on the idea of interconnection. App based messaging is a different business model,based on seclusion in an ad ecosystem. They could technically interconnect, bwt that's bad for the companies selling ads.", "Email is an open specification that is set up to handle sending from one server to another. Instant messaging apps are not designed for this. They're designed where one central server controls everything. In theory, you could create a protocol that was similar and allowed for the servers to send messages to one another to forward to the right user, but there isn't a business case for it.", "It's like school. Email is the first week of school where everyone is told to make friends with everyone else. The standard protocol is just to walk up to someone and talk to them. Open communication. That's how emailing works. Anyone can talk to anyone else they want. Messaging apps is what happens a few weeks later. Cliques start to form. People are now only talking to their friends. You want to talk to someone in a clique? Be cool enough to get into the clique (i.e., download the app) and they'll let you talk to them. Messaging apps don't talk to each other because they literally don't want to. They can set up a common protocol that allows communication, but it wouldn't benefit them, so they don't.", "Email is a standardized format that has been around for decades. It was created as a means of communication. Modern day messaging apps have proprietary formats so that you have to use their apps. Email was created to communicate, these means of messaging were created to keep you using their app." ], "score": [ 21, 11, 5, 4 ], "text_urls": [ [], [], [], [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2vulah", "h2vtffh", "h2w6269", "h2vuscn", "h2w0nel", "h2vzeun" ], "text": [ "Most plastic bottles have a bit of a softer, more flexible material in the cap that forms the seal.", "The plastic bottle and the cap, despite feeling pretty rigid, are still in the materials world, quite deformable. Thus, to a certain extent the lid and bottle where they meet will deform slightly under the pressure of the lid screw to form a seal together. The metal halves of a hose or pipe fitting are stiffer and the seal between the two parts will depend a lot on machining/manufacturing tolerances and fit. Meanwhile, put a highly crushable and deformable rubber 0-ring in between and it will fill in all the uneven gaps in the seal between the two metal fittings.", "Why, in my day, there was a removable plastic seal, like a coin in the cap of plastic bottles. Companies would run giveaways and other contests through instant win and collect-and-win cap seals. I'll be over here reminiscing...", "**Bit simpler** Plastics are solid materials, but quite soft compared to others like metals. To create a tight seal you want to fill every bit of space, something that can be squished into these spaces is good - such as softer O-rings around your metal tap. When you have something that is already a little bit squishy (plastics) being used with another slightly squishy (another plastic) thing, no O-ring is necessary. **Bit more complicated** An O-ring is a deformable polymer, typically a rubber material but other plastics can be used too. They are used as metals and ceramics cannot deform in the same way that plastics do. Plastics are rigid, but much softer than, metals and ceramics - hence O-rings are used to compress into all available spaces within a seal of some kind (such as around your water tap). With a plastic bottle it is two plastics, usually PET/HDPE/PP, these are able to compress to some extent into one another creating a tight enough seal to stop leakage.", "Have you never looked at a cap? They have a soft plastic seal built in. Remove this, and the bottle will likely leak.", "It’s hard for 2 cylinders to make a watertight seal, but easier for a cone to push into a cylinder to make a seal. That’s why most plastic caps have a tapered ring (the start of that cone) inside the cap. The threads are just there to make it easier to push that ring against the cylindrical hole of the bottle. To prove this for yourself, cut out the inner ring and screw the cap on tight. It’ll leak like crazy." ], "score": [ 530, 198, 32, 19, 18, 4 ], "text_urls": [ [], [], [], [], [], [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2vue9x", "h2vycpg" ], "text": [ "Cardio*vascular* The “vascular” part is important - when your muscles move they push blood through the system and take load off the heart. The heart is the primary pump in the system, but many of your muscles function as local booster pumps when they’re working. Exercise strengthens the heart and muscles and makes this system more efficient. A high resting heart rate just makes the heart overwork to try and pump up system pressure all by itself, damaging it.", "No, it does not make sense. Increased heart rate is only a small part of the benefits of exercise. Exercise produces appropriate levels of cortisol response, lowers triglycerides, increases capillary production and repair, strengthens muscles. The only thing stress can do is raise the heart rate and produce unhealthy levels of damaging chemicals." ], "score": [ 17, 7 ], "text_urls": [ [], [] ] }

[ "url" ]

[ "url" ]

{ "a_id": [ "h2vv5c0", "h2w1wr7", "h2vy4o1" ], "text": [ "What people used to call \"shell shock\" was likely a combination of PTSD, traumatic brain injury, and other neurological and psychological issues arising from war and being regularly exposed to bombardment and gas attack.", "Same thing, really. Context is what's different. Before the 20th century when industrialization really changed things battles were actually fairly quick things (relatively speaking). Lots of marching and preparation to get to a battlefield and then, hours later, a bunch of dead bodies. Horrifying? Sure. Stressful? Absolutely. But it wasn't just constant and unrelenting stress. I'm not saying it didn't cause psychological damage. It did. But the damage it did we pretty much got used to over the centuries. Then we roll around to World War I where people were in trenches. Crawling on their bellies in the mud while dodging almost constant bombardment at times. This went on for months and months and people couldn't get away from it and it just wouldn't stop. So suddenly we start having a bunch of soldiers who are becoming really inefficient. They are bad at following orders. You tell them to do something dangerous and they won't. They break down and start crying. What do you do? Well, in the old days you'd shoot them for cowardice. Unfortunately, that is more than likely what still happened at first. But when it isn't just one or two men but hundreds they start to get concerned. Shell shock was coined as a way of describing what they thought was happening. The explsions were shaking their heads and the brain trauma was the culprit. I did say we didn't really have a concept of the damage long term stress has on a person. Psychology was still in its early days and people still looked for physical causes at first. Someone else mentioned brain trauma and, yes, that was almost certainly a factor in many of these cases. But not all of them. \"She'll shock\" is basically PTSD. The biggest difference is how we treated them. Soldiers were forced to keep enduring as the stress crippled them and they were called cowards or useless. They were forced to stay right where they were because at that time we just assumed that as long as they were physically healthy that was all that mattered. So calling those soldiers shell shocked is not only accurate for the period it also reflects that the treatments at the time often made things worse.", "George Carlin [ELI5]( URL_0 ) the \"differences\" best. TLDW: there is no difference other than the weight of the words. Edit: fixed formatting." ], "score": [ 48, 4, 3 ], "text_urls": [ [], [], [ "https://youtu.be/hSp8IyaKCs0" ] ] }

[ "url" ]

[ "url" ]