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<\|im_start\|>user Why is it that a vaccine like J&J can reduce severity of Covid-19 even in cases where it doesn’t provide full immunity? The trials indicated that full immunity varied by country, probably due to the different strains. But it was effective at reducing severity across the board at similar rates, regardless of strain. Why does that happen?<\|im_end\|> <\|im_start\|>assistant Vaccines elicit more than just antibodies. They can also stimulate the differentiation of T cells that recognize the antigens (the proteins of the virus) and these help coordinate the immune response as well as destroy infected cells. For the virus SARS-CoV-2, how quickly the T cell reaction can respond is critical to how severe the disease can get. A rapid response often results in no or few symptoms, while a delayed T cell response can result in an uncoordinated immune scramble that results in severe illness and/or 'long COVID'. Vaccines that attenuate disease but don't prevent infection are common. The vaccine for shingles is given to people who have a latent varicella virus infection (after childhood chicken pox); it prevents the disease from flaring up.<\|im_end\|>
<\|im_start\|>user CMV: "Transracial" is as valid as "transgender". I made an account to post this because I deleted my old account. I know it may seem like I'm a troll but I'm not, I'm genuinely interested in this issue. I know there are some other topics up about the same thing, and I'm actively reading those, but my view still isn't changed. All of this stuff about Rachel Dolezal is really bothering me. I read a couple articles about how identifying as a different race then the one you grew up as is NOT the same as identifying as a different gender. One article in particular really bothered me because of how inflammatory it seemed: http://www.huffingtonpost.com/2015/06/12/rachel-dolezal-caitlyn-jenner_n_7569160.html (It's probably not necessary to read it to understand my viewpoint) If one can identify as a "different" gender, and even be called a hero for it, why can't one identify as a "different" race? I understand in this particular instance Rachel Dolezal lied for a very long time about her history, but even then, would a transgender person be demonized for lying about their history pre-transtition? (perhaps that's a debate for another time.) I'm desperately trying to at least understand these arguments. CMV? _____ > Hello, users of CMV! This is a footnote from your moderators. We'd just like to remind you of a couple of things. Firstly, please remember to *[read through our rules](http://www.reddit.com/r/changemyview/wiki/rules). If you see a comment that has broken one, it is more effective to report it than downvote it. Speaking of which,* *[downvotes don't change views](http://www.reddit.com/r/changemyview/wiki/guidelines#wiki_upvoting.2Fdownvoting)*! If you are thinking about submitting a CMV yourself, please have a look through our *[popular topics wiki](http://www.reddit.com/r/changemyview/wiki/populartopics)* first. Any questions or concerns? Feel free to *[message us](http://www.reddit.com/message/compose?to=/r/changemyview). Happy CMVing!<\|im_end\|> <\|im_start\|>assistant What is similar about race and gender? Not much. Gender is an identity that is tied to sex, a biological difference that in animals and, to some degree humans, completely dictates your role in society. It involves hormones and other definable physical differences that can be altered and changed. There is a biological basis to the differences between sexes, and to transgenderism. There is also a medical "cure:" hormone replacement therapy. Race is nothing more than a social division created by physical appearance. It doesn't actually exist. Black people are not the way they are because* they are black, but because of the historical circumstances that made them that way. You can't identify as having had different historical circumstances.<\|im_end\|>
<\|im_start\|>user [E.T.] Why did the extraterrestrials seem really worried about being discovered by humans during their initial landing, but didn't seem to care at all when they came back for E.T.? In the beginning of the film, the extraterrestrials are really on edge as they perform their research excursion, reacting to the slightest noise. When the humans show up, they collectively panic and high-tail it off planet, leaving E.T. behind. When they return, there's a bunch of humans milling around the landing site (including the ones who were chasing them initially!), but they don't seem to care at all. What changed? I got the impression that they didn't want to be discovered during their research mission, but when they return they don't mind at all that humans know about their existence. Were they afraid of humans' potential violent capacity at first, but then realized they weren't a threat?<\|im_end\|> <\|im_start\|>assistant Imagine a team of human scientists travel to a nature preserve to study the local wildlife. They will be careful not to disrupt the natural balance. Then one of the humans is injured and becomes separated from the group. They broke their sat phone and take refuge in a cave near a clan of chimpanzees. A baby chimp brings them some food and some random sticks and rocks it thinks are pretty. The human notices one of the "sticks" is actually an old antenna that fits in their sat-phone! The human scientist repairs the phone and calls for help. Then a rescue party is formed and sent to bring the scientist home. The rescue party doesn't have any scientists in it though, that would be dangerous and could risk another getting injured. So they send appropriately trained individuals like military, police, or emergency medical services to go pick up the hapless scientist. The rescue team cares little about disrupting the local wildlife, as long as they bring everyone home safely.<\|im_end\|>
<\|im_start\|>user What’s the difference between transcendental idealism and materialism? New to philosophy so apologies if this makes no sense. I’m struggling to see the difference between these schools of thought. To me transcendental idealism seems almost materialist. Kant says we live in a world of experience, experience of representations of ontologically real things in their self. Isn’t this world of the “Noumenon” materialist? Things happen, ultimately based on these real objects. I live my life according to representations of them, but what happens depends on that deeper reality beyond the representation. Struggling to understand! Thanks for any info<\|im_end\|> <\|im_start\|>assistant On Kant’s view, space, time, and causation, at least as we understand them, are conditions of our experience, and not something out there, independent of us. Standard materialism accepts the reality — out there — of some or all of these things.<\|im_end\|>
<\|im_start\|>user CMV: Diversity is not about race A diverse society is a society which has people from different backgrounds and cultures. How does race come into play? Take this example; a white child who immigrated from Chechnya to escape persecution and a black, American child, live next door to each other. They grow up together and, ultimately, have to postulate for colleges. The African American child, who has had an otherwise normal childhood, is accepted for the sake of diversity, while the child from Chechnya is rejected. Wouldn't the child from Chechnya bring more diversity to the school, despite his being white? Doesn't he contribute to a multicultural environment? Isn't it racist to assume that there is a "white culture" and a "black culture" ? Aren't people's backgrounds independent of the color of their skin? Diversity should be about diversity of experience and background, not skin. Diversity should be about bringing people from different socioeconomic statuses together, whether rich or poor, religious or non religious, American or not American, etc.<\|im_end\|> <\|im_start\|>assistant Most universities do have an essay portion where students can write about their background, elite schools especially have a pretty extensive essay section. Writing about immigrating from Chechnya to escape persecution would probably make for a very strong essay. Grades and test scores are only a part of admissions. Based on this, it's hard to say which kid would have a better shot at getting into the same competitive school. A generic black student has better odds compared to a generic white student but there are clearly lots of factors that could make either student stand out. It seems like a more accurate statement of you view should be "Diversity is about many things: country of birth, race, socioeconomic status, personal experiences" not "Diversity is not about race". It can be about race and other things as well.<\|im_end\|>
<\|im_start\|>user [Judge Dredd] Are the Mega-Cities independent of each other? So I am asking about how the Mega-Cities deal with each other. I understand that there are like a dozen mega-cities scattered all over the planet. Are they independent? Do they conduct trade with each other? What about the areas outside the mega-cities in the wastelands? Are there 'nations', 'countries' or 'empires' that exist in their own global order?<\|im_end\|> <\|im_start\|>assistant To all extents and purposes, each Mega-City is an independent sovereign nation, and acts as such in terms of trade, war, treaties, etc. They're generally pretty insular, but all the interactions we've seen them have has played out in the style of nations interacting with each other. There's no higher authority. As for the wastelands, no, there's not really any major powers there. It's just scattered towns and cities. Occasional attempts have been made to form powers able to rival the Mega-Cities, but all have failed. There's simply not enough resources to sustain anything major and besides, the Mega Cities don't want the competition.<\|im_end\|>
<\|im_start\|>user What is ‘lightweight code’?<\|im_end\|> <\|im_start\|>assistant Typically it refers to code that uses few system resources or has few features. If you're talking about libraries, it typically means the library has few dependencies, is easy to add to existing software, or only solves a single problem.<\|im_end\|>
<\|im_start\|>user ELI5:If everyone has a different set of tastebuds and we all have different levels of satisfaction/dissatisfaction towards different foods, then how do food critics have a job? Wouldn't their opinion be worthless? I will admit that I have not read a lot of food critic articles. But why would I read someone's opinion on food when they do not have the same sensations as me towards said food. edit: The basic gist of the correct answer in my own wording is that a food critic is an expert of explaining food. They know about texture, tenderness, presentation (like u/need2unsubscribe pointed out). They are not necessarily saying whether they enjoyed the taste. It is the same reason you read a book review, the critic will tell you about wording, ease of read, plotflow, and similarities with other books. This gives you an idea of whether you might want to partake in such a book, just like whether or not you would partake in an expensive meal. Thanks reddit.<\|im_end\|> <\|im_start\|>assistant this question could be applied to all forms of critics.......music, movies, tv but trying to answer the question, I'd say think about like the Iron Chef judges, their critique is usually about tenderness, texture, freshness of ingredients, presentation, etc. Stuff that transcends just taste. They are food "experts" so they can take a step back and recognize a quality dish without it being their personal favorite. also have never read one of these articles<\|im_end\|>
<\|im_start\|>user [King Kong 2005] How did the ancient civilization build structures at the inner part of the island since it's filled with dangers at every turn?<\|im_end\|> <\|im_start\|>assistant Plenty of possibilities. Everything from a smaller monster population when the structures were built to more advanced and numerous human settlers better able to combat the dangers. Could even be there were multiple kongs on the island that aided humanity similar to their monsterverse counterparts. These other kongs could have died out from disease or famine or just simply lower birth rates than the V-rexes that are their main competition for survival.<\|im_end\|>
<\|im_start\|>user ELI5:What's the core differences between the CIA, the NSA, the ATF, The FBI, the Secret Service and Homeland Security? Why can't they be combined into one agency? All seem to do pretty much the same thing. I'm confused as to what each of them can and can't do and the jurisdiction of each agency. update Thank you everyone for kind, thoughtful answers. I had a general idea of what each agency was supposed to do and assume they all work together as needed, just not the fine points/jurisdictions.<\|im_end\|> <\|im_start\|>assistant They all have very different charters and are tasked with very different activities FBI: detect and prosecute crimes against the United States CIA: Counterterrorism, nonproliferation of WMD, counterintelegence, cyber intelegence and forgien intellegence gathering NSA: global monitoring, collection, decoding, translation and analysis of information and data for foreign intelligence SS: Prevention and investigation of counterfeiting of U.S. currency and the safety of current and former national leaders and their families Don't believe what you see in the movies - they each have a very specific charter and duties. They are also all very large organizations with complex managment structures to control the power that the agencies wield.<\|im_end\|>
<\|im_start\|>user ELI5: Why were some ancient cities needed to be excavated? How does a city get lost due to "something" covering it? For instance, consider the city of Pompeii, which was buried under the ash from a volcanic eruption. What does it exactly mean? Did the entire city get covered and formed a plateau-like structure? How could an eruption cover a big area and not cover other surrounding places? Also, I was reading about cities in the Indus valley civilization and even in the Babylonian civilization, they too needed some excavation after which the cities were revealed. Are a lot of current cities over some ancient city? I'm sorry for a lot of questions, but I'm just curious with a lot of questions on that topic.<\|im_end\|> <\|im_start\|>assistant In many cases it's buildup of leaves,plants and dust that settles over decades-centuries and slowly covers everything. There is also a sinking action the soil can play when conditions are right and some buildings may sink from the bottom and be covered with plants and dust from top. &#x200B; Eventually a hill forms and people forget there was a city at all.<\|im_end\|>
<\|im_start\|>user If I croak, my cells die pretty quickly. Are the cells in fruit on my counter alive? If so, how long does it take for them to die?<\|im_end\|> <\|im_start\|>assistant Plants can have different parts separated from each other continue to live independently. Leaves, stems, fruits, etc. can continue to live as long as they get enough light, retain enough water, or retain stockpiled nutrients. It just so happens that fruit are designed to retain nutrients so they can live for a while waiting for an animal to eat them and spread the seeds. So when your apple shrivels its just consolidating nutrients and water towards the center where the seeds are<\|im_end\|>
<\|im_start\|>user Is there a terminal velocity for a buoyant object rising through liquid water? If so, how would one calculate it?<\|im_end\|> <\|im_start\|>assistant The forces involved are weight (W), buoyancy (B), and drag (D). Applying Newton’s second law, we find that W + D = B, or D = B - W. The buoyant force is ρ_f_gV, where ρ_f_ is the density of the fluid. The weight is ρgV, where ρ is the density of the object. And the drag is some function of the velocity; we can assume linear drag for low Reynolds number flows, so D = bv. So the terminal velocity is calculated at steady state, when these forces are all balanced, and the result is v_t_ = (ρ_f_ - ρ)gV/b. So it increases with the density difference, and decreases with the linear drag coefficient of the object.<\|im_end\|>
<\|im_start\|>user Why is cancer much more relevant now than it was a century ago?<\|im_end\|> <\|im_start\|>assistant Don't quite understand the question, but cancer tends to be a disease of older people and people live much longer nowadays. So, if you die of an infection at 32, you don't live long enough to die of colon cancer at the age of 55. Also, diagnostics have improved, so people are now correctly diagnosed with a cancer where in the past they may not have been. Cancer has been around for a long, long time.<\|im_end\|>
<\|im_start\|>user ELI5: How is it that if you cut a small piece out of a hologram you can still see the entire image in it, instead of just a part of it like you'd get from cutting up a photograph?<\|im_end\|> <\|im_start\|>assistant With a photograph, a lens is used to focus the scene on the film. Each part of the film only gets the light from one part of the scene. With a hologram, there is no lens. Each part of the film gets the light from the entire scene. Whether you're cutting a photograph, or a hologram, you only get the information that fell on that part of the film. With a photograph, that means information from only that portion of the image scene went through the lens. With a hologram, that means information from the entire scene. However, a hologram is like looking through a window. You can see the whole scene, and if something in the foreground is in the way, you can move a little to the side so that the foreground object is no longer in the way. This is called parallax. When you cut up a hologram, it is like blocking out the window so you can only look through a small part of it. You lose the ability to move side to side (or up and down) to look around objects. You lose parallax.<\|im_end\|>
<\|im_start\|>user How do I know if Computer Science is right for me? I am starting University this September and thinking of changing my degree pathway to Computer Science but not sure if it's right for me. Apart from coding/programming what does a CS degree entail? I have been looking at the Uni modules but don't really understand them as there's a lot of new stuff. I just started learning to code with Python and enjoy it so far and I like Maths in general but how do I know whether or not I will enjoy a CS degree and the jobs that come after Edit: Thank you for all those who reply and give advice, much appreciated.<\|im_end\|> <\|im_start\|>assistant CS itself is a mathematical discipline, but tends to teach programming as a tool along with a bunch of theory that's useful for writing efficient software. Some degree programs lean toward the theory and math, but the exact focus is going to depend on the program itself.<\|im_end\|>
<\|im_start\|>user ELI5: What causes that sound you hear when you cup your ears?<\|im_end\|> <\|im_start\|>assistant Surfaces reflect sounds. Surfaces of certain sizes reflect sounds of particular frequencies. A cupped hand will reflect some high frequencies more than others. The diameter of the "cup" focuses those frequencies into your ear canal, emphasizing them. Since these sounds, which would normally pass your ears unnoticed, are now emphasized, they are perceived as a rushing sound. Also, your position is space is given a reference as your brain interprets sound for clues to your location in relation to all sound-reflecting objects around you. Cupping your hand behind your ear interferes with those clues. Wait until you're older and your hearing naturally becomes less sensitive to those high frequencies and you'll find the effect is diminished or non-existent.<\|im_end\|>
<\|im_start\|>user ELI5: How do US Businesses like Apple affect the trade balance when its products are produced abroad?<\|im_end\|> <\|im_start\|>assistant Trade deficits are about as useful to characterize a nation's economic well-being as it is trying to determine a person's identity from a shadow. It only provides the broad outline. A massive trade deficit can be the result of over-consumption and/or under-production rather than purely antagonistic practices. If the latter were true, why would we (the US) ever enter into such an agreement in the first place? Consider the following: 1. Over-consumption. The reality is, much of the trade imbalance comes from the fact that the US has the highest gross consumption of products anywhere in the world and has the 2nd highest per capita expense (after the UAE, IIRC). It should be no surprise that the world's largest (in terms of gross size) market has a trade imbalance. For comparison, the average American saves less than 3% of their total income, compared to a country like China where the average savings rate is over 30%. Other countries are financing American spending by providing low cost of goods to meet our demands. Example: The average American has more than two cars and at least one firearm (per capita basis). In order to be able to buy and own these products at these rates, products from other countries have to flow in to meet the demand. Not everyone drives a Mustang and a F-150 with a AR-15 on the bed. 2. Under-production. A mature, service-based economy such as the US greatly under-produces compared to a quickly developing one such as India or China. It is simply the nature of business in the service industry. Also, high tech sectors often have to use high cost of goods to manufacture high tech products with decent quality. The relative unprofitability of a manufacturing based industry is not as attractive to US companies when they can simply import those goods (having foreign firms compete for the contracts), assemble those goods, and sell the final products in various global markets within those markets themselves. That way they can minimize expenditures on the raw materials while maximizing profits. Example: Ford sources materials from around the world, taking bidders on all sorts of contracts. Forcing those contracts to come from domestic sources via tariffs hurts the company in terms of their choice of suppliers and the increase in cost of goods. 3. High cost of domestic goods sold in foreign markets. So what about the other side of the issue? What about the export of American goods? It works in reverse as well, something that few people pause to consider. Example: Trump's claim that India has a 100% tariff on the US. Not sure what this actually means, but in reality, the cost of goods that are produced in the US makes them extremely over-valued in developing markets where the cost of living is substantially lower. Imagine a bottle of water produced in the US, why would you pay its full value in Rupees when you can get a cheaper form of it in India as an Indian? Either the product just will not sell in India or the Indian government has to eat that cost by not levying a tariff. 4. The real answer is that companies, meaning the specific entities, simply do not care about trade balances. They do not owe allegiance to any flag, they only are beholden to their stakeholders. In reality, the trade imbalance can be explained in many ways. Arguing that a trade imbalance somehow hurts a nation is widely misleading. The small amount of domestic jobs a protectionist tariff could create often pales in comparison to the wider issue of over-consumption and under-production of marketable goods. In reality, it only serves as the outline of trade relations between two nations. TL;DR: Rich nations that like to buy a lot of things need other nations to make up for the demand, thereby often leading to trade imbalances. Companies do not care, they are just out to make profits.<\|im_end\|>
<\|im_start\|>user ELI5: How can we have heart-lung bypass and kidney dialysis but not liver dialysis? What makes creating liver dialysis so difficult? Is it the functional complexity of the organ?<\|im_end\|> <\|im_start\|>assistant ELI5 version: The kidney is a filter. The liver is a factory. We can build pretty good filters, and add stuff back in if we need to. Replicating every single synthetic and metabolic function of the liver would take a machine that can perform thousands of different reactions at controlled rates.<\|im_end\|>
<\|im_start\|>user Eli5, how do selective herbicides such as broadleaf weed killer work? Why do they only kill certain things?<\|im_end\|> <\|im_start\|>assistant By targeting something that only that species or group of species have. Because they are broadleaf, that means they are all related. Much like humans, chimps, gorilla's all share many characteristics because we all primates. So we find something that all broadleaf has in common, that other plants don't and target that. It could be a chemical that inhibits their growth, prevents cell division, something like that. Anti biotics work in the same way. You take a drug that only hurts bacteria and not you, because it targets things only bacteria have.<\|im_end\|>
<\|im_start\|>user ELI5: Why specifically does the Northern part of Africa have desert land? I’m assuming it’s on the same geographical level as other countries that have no desert at all?<\|im_end\|> <\|im_start\|>assistant Climate is much more than just latitude Things like altitude, geography, air currents, water currents, all of that factors in. England for example is at the same latitude as parts of Canada that are covered in snow much of the year, yet England has a much milder climate. This is because the north Atlantic ocean current drives warm water and subsequently warm air right to the British isles. As for the Sahara it is believed that northern Africa regularly went through periods of humidity where it rained a lot and there were lakes and rivers and forests full of life, and periods where the air was dry and all the water dried up and everything died. This was caused by small changes in the planets tilt on its axis. Then at some point some factor changed in this sensitive balance that threw the whole system out of whack. Current thinking is that this coincides with the spread of humans and agriculture across africa. As northern africa was transitioning from a humid period to a dry period humans transitioned from hunter-gatherer to domesticated animals and farming in order to survive which could have lead to over grazing, over farming and destruction of vegetation. This vegetation would have been needed to provide the moisture in the air to trigger a new humid phase when the time came. Without it the next humid phase was never triggered and the system spiralled out of control leading to the eventual creation of the Sahara desert.<\|im_end\|>
<\|im_start\|>user [DC] When and how did Batman have the time to learn all his skills? Like He somehow learned like 20 different languages while also training his body to above Olympic level athlete , to learning and mastering every martial art to learning alll these different sciences and detective skills all at some point while traveling in his early 20s for like 3 or 4 yrs if that because he wass still early mid twenties when he became batman. He also somehow built the batcave in under a year also. How is he not superhuman??? How did he have the time for this ? unless he started this right after his parents died there's no possible way<\|im_end\|> <\|im_start\|>assistant The languages thing is a matter of practice and getting used to learning. That one is a real skill people have in real life, we just usually can't focus on it because of work and other responsibilities. He's rich, so he gets to do it. The Olympic level athlete part is part good genes (the Kanes and Waynes have basically all been buff) and access to good dieting and top-of-the-line equipment, which he acquires due to being rich. Mastering martial arts is basically a matter of engaging with senseis on their own level, and applying yourself as much as you can. While being a martial artist is usually either something people do for enlightenment reasons or as a hobby, Bruce Wayne is rich, so he can afford to grab whatever's useful from a martial art and move on to the next one without worrying about whether or not this is a good investment. He's more of a MMA master than a real Shaolin monk, for instance -- he probably can't do every single kata, but he can do the good moves and the good counters. The sciences part is overblown -- he's a very good chemist and forensic scientist, but overall he's reliant on the Batcomputer and allies to fill in his gaps. He got the Batcomputer to be the perfect second-hand knowledge source due to being able to afford it. I think the assumption here is that he only trained for 3 years -- that's not true, it was usually almost a decade. Most universes have Batman train for 8 years and then come back to Gotham in his mid-twenties, not when he's 21 or something. He also usually starts very early -- as early as 16 in some, but usually at 18. So his Batman career goes into full-force around age 26. He's as superhuman as someone who applies himself and has infinite resources is. He had time for this because he doesn't need to work to survive, he can actually plan out his life in advance and stick by it without worrying about emergencies.<\|im_end\|>
<\|im_start\|>user Is a human brain transplant achievable? If not, why?<\|im_end\|> <\|im_start\|>assistant For any organ transplant, you need to connect the new organ to the host. For most organs, that means some rational number of blood vessels and physical attachment to the surrounding structure. For a brain transplant you'd have to reconnect all the individual nerves...it would be like trying to replace a computer processor with tens of thousands of super tiny pins with no connector. We don't have the surgical techniques to do it with enough speed or accuracy.<\|im_end\|>
<\|im_start\|>user ELI5: How on earth do wells work? I don't understand how do wells work. Like, I've seen a lot of wells made of stone, so, if you dig a huge hole in the ground, how does water come inside the well? Like, I've seen a lot of movies where someone gets stuck in a well or something, and there's always a rock bottom. So, how does water get inside the well?<\|im_end\|> <\|im_start\|>assistant In certain parts of the world, there is a layer of water saturating the ground under the surface. This is called the water table. Pretend the water table is 9 meters below the surface. If you then dig a hole 10 meters deep, it will penetrate the water table. Water will flow into the hole, filling it to a depth of 1 meter. Water then can be removed from the hole, which is now called a well.<\|im_end\|>
<\|im_start\|>user What does it mean for a philosopher to develop a "complete philosophical system"? Like I read recently, for example, that Hegel is considered one of the last great "systems philosophers", having developed his own complete philosophical system. What does that involve? Does the philosopher have to touch on every branch of philosophy and come up with theories for all of them? Or do they have a broad theory that ties multiple branches of philosophy together?<\|im_end\|> <\|im_start\|>assistant I'd say both of your conditions need to be met: > the philosopher have to touch on every branch of philosophy and come up with theories for all of them More specifically, we could say that the philosopher has addressed every/most major branch of philosophy and.. > or do they have a broad theory that ties multiple branches of philosophy together? ...explained how their commentary on each of these branches of philosophy ties back to their overall system. Some philosophers, for example, don't do this; they may comment on a variety of philosophical topics, but they don't link it back to a central system. Kant is perhaps the best known "systematizer", while Nietzsche comments on nearly every branch of philosophy but does so in a very distinct, non-systematic way (hence the ease of finding passages that contradict each other.)<\|im_end\|>
<\|im_start\|>user ELI5: is the way we walk genetic? So i have noticed my cousin walks similarly of not exactly the same as my uncle. I feel like I also kinda walk like my dad. Is this just another genetic thing?<\|im_end\|> <\|im_start\|>assistant The way you walk depends on things like genetics, such as leg bone length which impact stride length. Fitness, a fat person might have a waddle like walk, a fit person might not. Health, such as injuries might give a limp or other change in stride length, or how the foot lands. If you've worn shoes most of your life or walked barefoot/sandals most of your life. It's not really one factor.<\|im_end\|>
<\|im_start\|>user [Harry Potter] If a metamorphmagus became an animagus, would those abilities interact? I.e. Would they be able to change their animal form's appearance? Or transform in to multiple animals?<\|im_end\|> <\|im_start\|>assistant Being a metamorphagus is an inherent genetic trait. Being an animagus is a learned skill. Turning into an animal also magically temporarily alters the wizard's base structure. It is likely that upon turning into an animal via their animagus skill, they would lose the metamorphagus ability while in that form, because changing their appearance is a genetic trait (like a veela's enticement ability) and not a spell (which animagus animals also can't cast).<\|im_end\|>
<\|im_start\|>user ELI5: Why do liquor bottles sometimes have those thing that make it pour really slow?<\|im_end\|> <\|im_start\|>assistant They are to measure the fluid. Barkeepers need to measure a lot of fluid in as short of an amount of time as possible. I don't know the exact figure, but they pour at around 1cl per second, so if the drink asks for 2 cl you pour for 2s. That is much more accurate than having an open bottle and just guessing how much you pour.<\|im_end\|>
<\|im_start\|>user ELI5: Why do so many people have seafood/shellfish allergies, yet red meat/ poultry allergies are so unheard of?<\|im_end\|> <\|im_start\|>assistant Most seafood allergies are a reaction to proteins in the fish or other seafood. We have much more in common with poultry and beef than we do with fish. We share a lot of the same proteins so an allergic reaction to one of those would have killed you because you're made of it. So we are more likely to have a reaction to fish than other meat because we have less in common with it so there are more things you could potentially react to. Another factor is cooking. Heating breaks down protein that in its uncooked form could trigger a reaction. You wouldn't consider eating a raw burger or chicken breast but sushi is commonplace. This is also why you hear more red meat allergies than poultry. No one wants undercooked chicken but a rare steak is usually preferred.<\|im_end\|>
<\|im_start\|>user [Marvel Cinematic Universe] How did HYDRA maintain its infiltration of SHIELD for nearly 70 years? I'm not asking how they avoided being exposed in that time (Zola answered that), but rather where all these younger people, like Sitwell, who would have been too young to even remember WWII. was it a chain reaction of "I can trust this guy; I'll recruit him as another HYDRA plant" starting with Zola and continuing to the present? Or was it done some other way? It's not easy to sell a conspiracy that robs the world of its freedom.<\|im_end\|> <\|im_start\|>assistant You start by choosing people carefully. Based on their political and moral views. You gain their trust and get to know them and make you and other hydra members most of their social circle, re-enforcing their views by sharing them, pushing them further slowly. Then get them to agree to the fact that the current system is flawed and that they need to make a change if they are to actually achieve what SHIELD is meant to do. They agree, suggest that there needs to be some sort of SHIELD within SHIELD that is dedicated to protecting mankind even above their own survival, that they don't care about how the world sees them or if they ever get recognition. They are the true heroes, willing to be seen as criminals for the greater good, not like the Avengers who took the easy route of adoration and celebrity status. Once you have them on board with the idea you tell them whatever they need to know. You don't even have to tell them about HYDRA at this point. They are just a secret group within SHIELD that are willing to break the law and even the rules of SHIELD to see the goals and aims of SHIELD met. Eventually you can reveal that HYDRA weren't as bad as they were made out to be. That they wanted the same thing, but, went about it all the wrong way. They tried to enslave mankind and joined with the Nazis which was a wrong decision. It's not like HYDRA supported the death camps or the extermination of Jews. They just happened to form in the territories of an empire that was led by a man who was elected into power that did have those views. Just like how we work within SHIELD, not following their beliefs or rules entirely, so did HYDRA work within the borders of the Nazis in the same way. HYDRA do what needs to be done, regardless of our individual desires or concerns. We sacrifice our own ideals, or own souls, our own morality to see that the world survives. We are the heroes the world deserves, just not the ones it needs right now...<\|im_end\|>
<\|im_start\|>user ELI5: I often hear about new planets being discovered with water beneath the surface, but rarely about planets with large oceans. Is subterranean water easier to detect or more likely to occur, and why?<\|im_end\|> <\|im_start\|>assistant Water only exist in a liquid state at a narrow range if atmospheric conditions. Many planets have surface temps far too hot due to proximity to s star or lack of protective atmosphere. On these planets beneath a protective layer of crust is the only place liquid water can exist. Flip that logic and there are planets with icey surfaces due to extreme low surface temps and atmospheric pressure conditions. Those planets with an active core such as ours may allow liquid water deeper under the surface where the temperature is above freezing point.<\|im_end\|>
<\|im_start\|>user How do 'after-tastes' work? Why do we get a different taste only after the food has been swallowed?<\|im_end\|> <\|im_start\|>assistant When you put food in your mouth, the 'taste' you experience, besides its physical characteristics, is a combination of the basic flavors identified by your tongue, such as sweet, sour, etc. and the scent, which is actually picked up by your nose. Your sense of smell is such a major component of the smell of "taste" that if you block it, you'll have enormous trouble telling foods apart. The scents don't have to be inhaled either: your mouth hole and nostrils are actually internally connected roughly at the point where you swallow, so smells from the food you're eating will travel upwards from there. So having explained that, the reason why sometimes you will experience an aftertaste will be more understandable to you: because the food that has sat in or passed through your mouth is considerably different from the one that you first experienced when it went in. You chewed through it, exposing its inner parts, and then mixed it with your saliva which is packed with enzymes that we have specifically evolved for their ability to chemically break down the foods we stuff in our mouths. This breaking-down mush then stays on your tongue, in your teeth, and in spots on your mucous membrane, and the smell makes it up to your nose. And it's changed because you changed it.<\|im_end\|>
<\|im_start\|>user Say I move a large pile of rocks. Will I burn the same number of calories no matter how I do it? For instance of I move them all in one day or do it over several days, or if I use a ramp to move them or a pulley system, is the amount of energy used the same no matter? Would I see differences in muscle development depending on technique?<\|im_end\|> <\|im_start\|>assistant In terms of mechanical efficiency, it will take different amounts of energy to slide the rocks across the ground or pick them up. It also takes different amounts of energy depending on how high you lift them, and whether you place them down, or just let them fall using gravity. In terms of your body, it depends on a massive number of things. For example, some people would be better off taking all the rocks at once, some would be better taking a few at a time, and some would be better taking only one at a time. Taking many rocks at once would put a higher stress on your muscles, since more fibres need to activate at any one time in order to carry them. Taking one rock at a time wouldn't use many fibres, but would be more stressful to your cardiovascular system, if you are doing them one after the other. There is no real way to say how a person would use more energy, because it totally depends on the person, how fit they are, how strong they are, and what type of prior training they have done.<\|im_end\|>
<\|im_start\|>user ELI5: That euphoric half-asleep feeling where you're still semi-present but your mind is also solving tangential abstract problems that you can never remember upon fully waking.<\|im_end\|> <\|im_start\|>assistant One definition of a brain is that it is a "meaning making machine", it takes stimuli from your sensory organs (eyes, ears etc) and constructs a mental picture of the world. We still have a fairly rudimentary understanding of how brains achieve this, and whilst we know that sleep is essential for survival, we don't have a solid answer on exactly what's going on, but we do know that a huge amount of (seemingly random) brain activity occurs during REM sleep. I think the experience you describe is the product of your brain trying to make sense of the scrambled messages as bits of it wake up and other bits are still asleep.<\|im_end\|>
<\|im_start\|>user Are there proteins that do nothing? Neutral things that natural selection didn't "care about". Surely it must be the case, just like we have useless bones, right? Or would such proteins be necessarily bad for our body?<\|im_end\|> <\|im_start\|>assistant There are lots of proteins, the function or full range of function of which has not yet been elucidated. This doesn’t mean they aren’t important. As others have said, it’s likely that they are, else they’d have been purged from the genome because of the energy taken to make them. But how important they are may depend on other things like the other genes present in your body, or your environment. However, there do appear to be proteins that can be totally knocked out with no apparent adverse effects and some significant benefits. One famous example is PCSK9, which binds to LDL receptors, initiating their endocytosis and degradation. This decreases the amount of cholesterol your cells take up and so is important for homeostasis. The kicker is that people with two LOF copies of this gene are perfectly healthy and are actually protected against high cholesterol. So now PCSK9 is a target for treating hyperlipoproteinemia.<\|im_end\|>
<\|im_start\|>user Why didn't the leak in the ISS vent all the air immediately? I assumed that because there's no air in space, and lots in the ISS, it would shoot out incredibly fast. Is my assumption just plain wrong or is there more at play?<\|im_end\|> <\|im_start\|>assistant The mass flow rate is related to the differential pressure and the geometry of the opening. In this case the differential pressure is low (14.7 psi) and the opening was fairly small. Catastrophic failure can occur if the jet velocity has enough energy to make the opening larger by wearing away or deflecting the material. In that case you have a chain reaction.<\|im_end\|>
<\|im_start\|>user Tips for Reading Foucault So, I've just begun reading through Foucault's "The History of Sexuality" (about 50 pages so far). Up till now I have, for the most part, "ignored" some of the stranger meanings carried by his language and word choices, and just tried to focus on getting the "gist" of what I felt he was trying to say in a passage/chapter, however, I am becoming increasingly unsure whether I am reading "properly". I am wondering whether anyone might be able to give me an idea of how seriously I should be taking some of his stranger descriptions throughout the book? An example of such a passage: "...all this made the family, even when brought down to its smallest dimensions, a complicated network, saturated with multiple, fragmentary, and mobile sexualities." Looking at this passage, I can get a sense (I think...) of the point Foucault is trying to make. But how specific are words choices such as "fragmentary" and "mobile" here? Are they merely meant to illicit certain notions within the reader, or do they have a more precise purpose?<\|im_end\|> <\|im_start\|>assistant As a general practice, it never hurts to read philosophical texts once to get the gist, or at least an impression. But then it's good to read it again to try focus on details, structure, argumentation. Maybe just bank on reading it twice? As for peculiar words and phrases--it's good you're noting them. Often asking yourself what about these is unclear or attention-worthy can lead to insightful readings of the texts. The bottom line is to read more than once and to notice when you're noticing.<\|im_end\|>
<\|im_start\|>user ELI5: Why does a graphing calculator with a 4 inch gray scale screen cost more than a quad core tablet with 1080p screen?<\|im_end\|> <\|im_start\|>assistant Schools often mandate specific calculators for specific classes. This is for two reasons. One is that instructions can be very exact: hit this button then that button then enter these numbers and get a result. Also it's to prevent cheating that you could do on a general purpose computer. So since students have to buy these calculators, just like text books they have a smaller market than general computers (costs are spread over a smaller market), and since buyers are forced to buy them, they can set a higher price and margin.<\|im_end\|>
<\|im_start\|>user What conclusion can be drawn from statistically insignificant results? (Layman question and text provided) Hello guys, I just wanted to ask you if somebody could give me very basic (layman) explanation about one question. If for example you did an experiment on yourself where you tried a drug to see if it helps you with your condition, you took it 100.000 times but it only helped you 3 times. What conclusion can you draw from this? Is the result statistically not significant and therefore the hypothesis that a drug helps you can be rejected (so you can conclude that this drug doesn't help you). I know this is a very lame example, but try to give me an explanation for this particular scenario. It seems logical for me to conclude that a drug doesn't help, but I want to see it backed up by science. Thanks in advance!<\|im_end\|> <\|im_start\|>assistant The example you gave is not quite enough to explain the meaning of statistical significance. You took the drug 100 times and it helped you 3 times so it worked 3% of the time and there is not much else to say about it. To use statistical significance you have to compare the drug to something. So you would also have to take a placebo 100 times. Let's say the placebo "helped" (you got better) 1 time. Now you have 2 sets of figures: drug worked 3% of the time, placebo worked 1% of the time - and with this you can do some maths. Basically the question statistical significance attempts to answer is: is this 3% vs 1% difference due to chance, or to the drug actually having some effect? Now we have to back up a bit and explain what is meant by "chance". "Chance" arises because you cannot take the drug (or the placebo) every day forever. If you could, by some stretch of the imagination, take the drug every day forever and find that it worked (say) 6% of the time, and then (maybe in a parallel universe) take the placebo every day forever and find that it worked 4% of the time, there would be no need for statistical analysis: the drug works better, 6% vs 4%, no further calculation required. Unfortunately you can't do that - we have to analyze the 100 times you took the drug and the 100 times you took the placebo - and so, statistical analysis. The "by chance" refers to the fact that the 100 times you took the drug and the 100 times you took the placebo can be considered samples of the situation in which you took the drug or placebo everyday forever. Let's say that the "actual" response rate when taking the drug everyday forever is 6% (NB we have no way of knowing the "actual" figure, this is just for illustration) - a sample of 100 from this scenario could produce a response rate of 5% or 6% or 4 % or 3% or 2% or indeed any number. It is more likely to be close to the "actual" 6% than not, but it could be anything from 0 to 100%. In short, the response rate in your sample of 100 is affected by chance, because of the fact that you can only take samples, and never know the "actual" response rate. What statistical significance does is this: it assumes that the "actual" (everyday forever) response rate to drug and placebo are the same, then it asks what is the probability p that the figures we got (3% vs 1%) are purely because of the fact that we are restricted to taking samples of 100? The maths will then crank out a figure - say p=0.06. This means that the probability that you got the 3% and 1% figures despite the "actual" figures being equal is 0.06. Before turning the maths crank you should have already decided on what "p" you would consider statistically significant. Let's say it was p=0.05. That being the case, the figures show that there is no statistically significant difference between the drug and the placebo. In other words you have concluded that the figures your experiment has produced have come about by chance and the "actual" figures for drug and placebo could be identical. TL;DR: "Statistically not significant" means that the figures your experiment produced could have come about by the fact you that have to sample, rather than from an "actual" difference between the the two treatments.<\|im_end\|>
<\|im_start\|>user ELI5: The Earth's magnetic field periodically reverses polarity. How does this happen and what are the effects felt on Earth?<\|im_end\|> <\|im_start\|>assistant The effects are relatively unknown. We know a good number of species rely on magnetism to navigate, so there might be a critical moment that could lead to a kill off event where magnetically dependent species just get lost and die. Or they will just notice everything's been flipped. It's hard to test, I've seen experiments involving lobsters, it seemed to show that lobsters where totally loyal to direction of the magnetic North to find better grounds. Though unfortunately it had a serious observer effect that made it a bit unusable. There is no good way to say for sure. It happens because our magnetic field is generated by the spinning ball of metal in the earth's core that is totally surrounded by liquid metal. There isn't really anything there keeping it facing one direction or the other. It will almost always be facing geographic North or south due to its spin.<\|im_end\|>
<\|im_start\|>user [Fatherland]how is Hitler still alive in 1964, his drug addictions were already basically killing him when he shot himself in our timeline? Hitler was regularly taking opiates by 1941, which is a year before the novel deviated from our timeline in 1942. EDIT:https://www.npr.org/transcripts/518986612?t=1651359365895<\|im_end\|> <\|im_start\|>assistant 1. Being head of state gives you an impressive amount of medical care. The leading factor with disease is wealth, and the Reich would go to extreme lengths to avoid their Victorious Leader dying of an overdose in a back alleyway. Even in the 40s and 50s, we had enough medical tech to keep him alive. 2. The leading factor for drug addiction is extreme stress, and here hitler is no longer fighting a losing war against the entire planet. Basically, barring major incidents like a world war, world leaders live a long time. No-one can fight the reaper forever, but people with an entire state dedicated to keeping them alive can do pretty well.<\|im_end\|>
<\|im_start\|>user ELI5: Why are certain foods considered breakfast foods? Is there anything particular about eggs/pancakes/cereal/oatmeal that make them considered breakfast foods? Is it because they are simple to prepare and high in protein or calories to keep you fueled?<\|im_end\|> <\|im_start\|>assistant Every culture has foods that they start to eat for breakfast. After a while they become the traditional breakfast option for that culture. American breakfast evolved from our Agrarian lifestyle where farmers and ranchers needed high caloric intake but had little free time. They had large breakfasts, little to no lunch, and medium to large suppers.<\|im_end\|>
<\|im_start\|>user ELI5:Artificial food flavoring How do scientists figure out how to get some chemicals to taste like something else, specifically a certain flavor? Example: Propel watermelon flavored water. Has no mention of anything watermelon-y, yet tastes like watermelon.<\|im_end\|> <\|im_start\|>assistant Well, "watermelon" can be re-described in terms of chemically-sounding names. Everything is made of chemicals, so you can think of it like two languages: everything has its common name (watermelon), and it's technical, chemically name. Any naturally-ocurring chemical can and has been recreated in a lab. One day, a scientist decided, "I wonder what makes watermelon taste like watermelon". He got some watermelon and his analysis equipment and figured-out what chemicals are in watermelon. He identified which specific one is responsible for the taste, and "presto". Synthetic watermelon flavoring.<\|im_end\|>
<\|im_start\|>user Why is the derivative of e^x the same as e^x? It baffles me that the gradient function can be equal to the function itself. Anyone care to shed some light on this?<\|im_end\|> <\|im_start\|>assistant First, remember what a derivative is: The "rate of change" (or "slope") of the line/function. So, at a certain value of x, the function e^x is changing at a rate of e^x (the slope of e^2 at the point x=2 is e^2). Other functions have this property at a single point: f(x) = x^2 => f(2) = 4 f'(x) = 2x => f'(2) = 4 e is a special case because this quirk exists long its entire curve. Also, don't forget that the derivative of e^2x is 2e^2x - only e^x acts as a derivation identity.<\|im_end\|>
<\|im_start\|>user ELI5: Why are Asia and Europe considered different continents?<\|im_end\|> <\|im_start\|>assistant Both the idea of dividing Europe from Asia and Africa and the concept of a continent comes from Europe. So it is not surprising that European see Europe as a continent even if newer Earth science uses a different and more coherent scientific term for large landmasses. While several arguments can be made about the inconsistency of the references, Europeans will always see themselves on their own continent, and most of the world will always refer to Europe as a distinct continent. ‘Europe’ and ‘Asia’ was divided by ancient Greeks who were the first to referr to Europe as current Greece and Asia as current Turkey. They divided the world that they were able to travel on their ships into these two parts many centuries before the word 'continent' was invented. They divided what they knew as 'Europe' and 'Asia' and 'Africa'. According to the etymology of the word 'continent land' it was derived from the 16th century English term 'continuous land' meaning mainland or a continuous tract of land.<\|im_end\|>
<\|im_start\|>user ELI5: How does Eye color play into attraction? I've heard it mentioned many times that the eyes were often the first thing someone was enamored with and its often the thing someone remembers their SO over, men/women with Bright/striking Blue, Green, Hazel Etc. are notable examples.<\|im_end\|> <\|im_start\|>assistant Looking into someone's eyes can reveal a lot of information about how that person thinks of you. For example, if you look into your date's eyes and they dialate, you are much more likely to think they have pretty eyes. This is because eye dilation is a sign of arrousal in this context. Similarly, pupil dilation shows interest in other contexts as well.<\|im_end\|>
<\|im_start\|>user ELI5 how scientists know what compounds are in the atmosphere of a planet that's light-years away How do they figure out there's methane on titan for example? Edit: titan was just an example because I know they discovered methane there. Yes, I know it's not light-years away. It's not a planet either. Feel free to have an imagination of a five year old.<\|im_end\|> <\|im_start\|>assistant Spectroscopy. Different elements and substances absorb different, specific wavelengths of light. You can therefore analyse the light from objects, see what wavelengths are being absorbed, and work out what it's in the atmosphere.<\|im_end\|>
<\|im_start\|>user Are there any parasites that inhabit a valuable ecological niche? Do we need parasites? Are leeches and ticks necessary? If we eradicated botfly would another species suffer?<\|im_end\|> <\|im_start\|>assistant There is some speculation that the eosinophilic aspect of the human body which functions to target parasites (and is also responsible for the development of allergies, asthma, and other “histamine” related conditions) needs exposure to parasites and other infections to be properly trained. In the modern world, we have barely any exposure to parasites, so the theory is that the eosinophilic arm of the immune system doesn’t have anything to target, so it’s more prone at targeting the “self” which contributes to allergies and asthma and eczema, etc. This is corroborated by the finding that the developed world has significant rates of these conditions whereas parts of the world that are much less developed and do regularly encounter parasites have minimal rates of these conditions.<\|im_end\|>
<\|im_start\|>user How fast would one need to accelerate a container of air to make it bunch up to one side, creating a vacuum on the other? Back when railroads were new, alarmists feared that the speed of the carriages going as fast as 20mph would create a deathly situation for the passengers. This was obviously quite wrong. But how quick of an acceleration WOULD be needed to start heaving the air in a contained space over to one side of it?<\|im_end\|> <\|im_start\|>assistant For something like a planet with an atmosphere, you can define what's called a scale height which is the height at which the density is reduced to 36%. For planets, the simplest expression is h=kT/mg where m is the mass of the molecule, g is the gravitational field strength, k is Bolztmann's constant and T is the temperature. For Earth, this is roughly the height of Mt. Everest. For a train you can replace g with the acceleration, and if you want h to be 10 meters, the acceleration would to be about 1700 g's.<\|im_end\|>
<\|im_start\|>user ELI5: Why can't Godzilla-esque monsters exist in nature ? I understand that food and energy levels would be and issue, but is there anything else stopping gargantuan creatures evolving ? Same for giant flying creatures, bigger versions of real animals, insects and sea creatures. Thanks.<\|im_end\|> <\|im_start\|>assistant Gravity and oxygen are your limiting factors. Too big, and you can't form bones strong enough to support the weight, and you would need gigantic lungs to support the body mass required. You find larger animals in the ocean, such as blue whales, because gravity isn't a factor there. In the time of the dinosaurs, there was a much higher concentration of atmospheric oxygen, so it was easier to get the required oxygen.<\|im_end\|>
<\|im_start\|>user ELI5: If natural selection is based on survival of the fittest, why do most people instinctively and passionately protect the weak? Why is it almost universally considered unethical to kill (or let die) less "fit" people? Edit: I strongly believe the weak and "unfit" should be protected, I just don't understand why that is such a pervasive and powerful instinct when the basis for our evolution is essentially refining the gene pool by letting weaker members die off.<\|im_end\|> <\|im_start\|>assistant Fit also means being able to operate in groups. Humans who have group instincts will alway beat humans whose instinct is to be alone, no matter how fit they are individually. Part of the group instinct is fairness and to protect fellow members. So we don't always protect the weak (or else there wouldn't be a homeless problem), but we have urges to protect everyone that is part of our group.<\|im_end\|>
<\|im_start\|>user Overwhelmed by philosophy- I feel agnostic about all of my values, and it is sickening and preventing me from doing much. Every since I was introduced to philosophy there is this constant awful agnosticism of my personal values. I feel like love is real, but then I go out to dinner, and the people I am with all agree that polygamy is "the way of the future", and everyone there agrees, and there is this twisted feeling in my stomach bc I cannot explain love to them bc I am not in love now so I can't see forms right now, and then I start to doubt if Plato's forms even exist, or if it is just chemicals. I look online to clarify my views about philosophy of love or philosophy of sex (and these are just two example)- and there are hundreds of competing theories. I don't know what my values are regarding love, relationships, sexuality, anymore. I really do not know if god exists. Over the past two years- I began agnostic, went to atheist, and now I am pretty sure that there is some sort of god- whatever that word means. I don't know how I should live. I will return to college next year, but I just hate feeling agnostic and overwhelmed by all of this. I am seriously confused about the entire topic of metaphysics and epistemology. My philosopher professor was a materialist and a pessimistic one too- I do not know if he is right. I have not even touched political philosophy, philosophy of science, aesthetics and value theory- and I fear it.<\|im_end\|> <\|im_start\|>assistant If you want to feel better just follow Hume's advice: arguments may sound convincing, calling your pet theories into question, but at the end of the day just do what you think is right. Or, from the other end, if you are suffering from Kołakowski's law of infinite cornucopia (there are always arguments for competing positions), do the same thing: do what you think is right. If a lot of people around you start saying, 'what you're doing is wrong because X' then take a minute to reevaluate what you're doing in light of X. In the end, it doesn't matter that much if Plato's forms exist, reductive materialism is true or false, or whether you agree that polygamy is A-OK (don't worry: you don't have to marry two or more people if you don't want to. Love will also still exist even if it's between more than two people). And don't worry about your doubts over the existence of a god. Doubt is a good thing. So you haven't made up your mind yet. Many people never make up their minds--they're open to change.<\|im_end\|>
<\|im_start\|>user Does nuclear fusion produce radiation like nuclear fission?<\|im_end\|> <\|im_start\|>assistant There are two types of radioactivity that can come from fission/fusion. The first is prompt radiation - this is particles given off instantaneously during the fission or fusion reaction. For instance, fission of a U-235 nucleus leads to the emission of 2-3 neutrons, gamma rays, and two energetic fission products (which are just two smaller nuclei). Fusion of deuterium and tritium (H-2 and H-3) gives off a neutron. So both of these reactions lead to prompt radiation. Prompt radiation is mitigated by shielding the reactor core. The other component is due to the instability of the products of the reactions. Due to some characteristics of the stability of atoms, the products of fission are almost always radioactive. In other words, when the uranium nucleus splits into two pieces during fission, these pieces go on to decay later in other ways. This is what causes spent nuclear fuel to be radioactive. There are several different fusion reactions that could be theoretically used to produce power, but most of these don't lead to the creation of radioactive products. For instance, in D-T fusion, the product is helium-4 (which is quite stable). There are secondary ways in which the neutrons emitted by fusion can lead to the activation of materials within the reactor, but in general there is very little radioactivity in the products of nuclear fusion.<\|im_end\|>
<\|im_start\|>user ELI5 how does scientist exactly describe or know a very, very far away planet with interesting properties like lava ocean and raining rocks?<\|im_end\|> <\|im_start\|>assistant For the most part they don’t know. Here is how they determine properties: first they look at the parent star. From the light, brightness, relative movement of the star, they can figure out the size, mass and composition go the star. They detect the planets mostly by measuring the light of the star. Every time the planet passes in front, scientists measure the dip in intensity. From that they can determine the mass and distance of the planet to the star. From the stars composition and the distance to the star, along with the mass of the planet, using models for the formation of star systems, they can make predictions, or educated guesses about the chemical make up of the planet, as well as surface temperature. Finally, hopefully we are able to do this soon, we will be able to see light shining through the atmosphere of the planet with a powerful enough telescope. This will give info on how thick the atmo is and what exactly is in it.<\|im_end\|>
<\|im_start\|>user ELI5:Bullet sizes what are the demensions? when someone says 55.6 by 44, is that the tip or the casing?<\|im_end\|> <\|im_start\|>assistant Caliber is the width of the barrel of a firearm, which should also essentially be the diameter of the bullet. You'll see two different naming conventions, depending on where/when a round was invented. Rounds invented under the metric system will have the diameter in millimeters, followed by the length of the cartridge case. For example, 5.56x45 has a 5.56mm wide diameter and a 45mm long case. The length of the cartridge matters because a longer case holds more powder, which means the round will travel faster. Rounds invented under imperial (standard) units will name the diameter in hundreths of an inch. For example, .50 BMG is half an inch wide. Standard rounds do not list the length of the cartridge. However, most standard-unit rounds have some sort of extra name attached to them to help identify the specific round (.22 "long rifle," .38 "special," .223 "Remington," etc.)<\|im_end\|>
<\|im_start\|>user I understand why different atoms have different absorption spectrum, but why does a given atom have several "peaks" in its spectrum? I would assume it's because each electron will give off a different amount of energy. But hydrogen only has one electron, and it has 5 peaks (at least in the visible spectrum, don't know if it has some elsewhere) so I suppose that's busted. Anyone care to explain?<\|im_end\|> <\|im_start\|>assistant An atom is a bound quantum system with a discrete energy spectrum. This means that independently of how many electrons are involved, the whole thing can only take on a discrete set of energy levels. (And still be called an atom). An atom emits a photon or absorbs one by transitioning from one energy level to another. Since the energy of the photon must be the difference of these energies, the possible photon energies also form another discrete spectrum. Here's a specific example for the hydrogen atom in the simplest possible treatment: the energy levels are of the form: E = constant * 1/n^2 Where n = 1, 2, ... is an integer. Therefore the photons emitted or absorbed must have energies given by all the possible differences E_γ = const * (1/n_1^2 - 1/n_2^(2)) With n_1 and n_2 taking all possible positive integer values. So in the photon emission spectrum we will find a forest of peaks corresponding to these discrete photon energy levels (each corresponding to a transition between two atomic energy levels) and generally a handful will fall in the visible portion. A couple of corrections to this: first of all when atoms are in molecules, they don't retain their own electronic structure, part of the electrons will be shared between atoms in molecular orbitals. So you should talk about a molecule's energy levels and emission spectra, and all we said should really be said about molecules, not atoms. The spectrum of molecular hydrogen is not the same as that for atomic hydrogen. Typically, an atom will have a valence shell of electrons shared in molecular orbitals, while the inner shells will be mostly "his" and will display typical (generally high-energy) transitions of that specific element. Point number two is these peaks are not perfectly narrow. There is some "spread" to the photon energy. There's two reasons: one is quantum uncertainty. This makes the peak get a Lorentzian shape. Second reason is the Doppler effect due to thermal motion of the molecule with respect to you, the gentleman with the detector. This makes the peak get a gaussian shape.<\|im_end\|>
<\|im_start\|>user What determines absorbency? How come bread absorbs water, but not metal? My guess is it just has to do with surface tension, pockets of empty space in the material, maybe having to do with if the solid reacts to the substance to create a single mushy material. Bread and towels don't "absorb" the same way, I realize, because I can get towels dry again and they're the same as before. Can't just "dry out" bread.<\|im_end\|> <\|im_start\|>assistant Absorption is one part the amount of room available and one part the strength of the interaction between water and the object. Bread for instance has many small cavities for compounds to enter and bind to which gives it the ability to absorb fairly large amounts of water, but this is only part of the equation. Most metals actually do absorb water, but it just doesn't have the same amount of space to absorb large amounts of water. For instance water can form a weak chemical bond with platinum on the order of 45 kJ/mol. This is fairly close to the amount of energy two hydrogen bonds give. The thing is as soon as platinum forms a water mono-layer there isn't much room for extra water to bind to the surface and it instead beings forming a droplet, but this droplet will still be very "stretched" compared to other surfaces. You can actually see how much water likes to bind to an object by how much it beads up. For instance put a water drop on your hand (Try to pick the flattest area possible for best results) and observe the shape of the droplet. Try to keep your hand steady. You'll notice it spreads out a little, not much, but enough to notice. Now try taking a little Vaseline and spread it across your hand and repeat the experiment. You'll notice the droplet now beads up on top of the Vaseline. Lastly take a droplet and place it on to a flat metal surface. You'll notice the water spreads out even more so than on your hand. This is because for surfaces which water has a strong interaction water prefers to maximize the surface interaction while for surfaces that water doesn't like it prefers to minimize the interaction. In the case of absorption this plays a role. In fact did you know if you have a crystal of table salt there is often a layer of water on the surface of the salt?<\|im_end\|>
<\|im_start\|>user Why is Bismuth so non-lethal, compared to other heavy metals? Especially considering its neighbors are Thallium, Mercury, Lead, and Polonium. Specifically, why can we ingest it via pepto-bismol? Is it the element itself which is safe, or the way it's bonded in the compound? If it is the former, what makes Bismuth safer for us? If the latter, why is pepto safe, yet various lead compounds are not?<\|im_end\|> <\|im_start\|>assistant One property of bismuth that separates it from other heavy metals is that it does not accumulate in an organism. This process is called bioaccumulation, and is the reason why its neighboring elements are so much more toxic. With lead, for example, if an organism ingests it, the rate of absorption of lead in the body will be greater than the rate of removal from the body. With bismuth, the body removes it so quickly following ingestion that there is no time for absorption. The half life of bismuth when it is inside an organism is five days. This is not to say that bismuth is safe though, so dont go off and eat a tuna and bismuth sandwich just yet. Even though it may not stay in your body as long as other heavy metals, bismuth poisoning does exist and can harm the kidneys, liver, and bladder. Also, one of its main suppliers, Alfa Aesar, notes that it can cause skin, eye, and GI irritation.<\|im_end\|>
<\|im_start\|>user How does Hawking's area theorem reconcile with Hawking radiation? Hawking's area theorem says that the area of a black hole's event horizon can never decrease, only increase, similarly to entropy. Further, the radius (and hence, the area) of the event horizon is determined by the mass inside the horizon. At the same time, Hawking's theory that quantum effects near the event horizon can cause Hawking radiation implies the black hole can evaporate. I suspect I'm missing some simple nuance of one or both of the theories that reconciles the two, but if the event horizon can never shrink and the area of the horizon is determined by the hole's mass, then how can black holes evaporate through Hawking radiation?<\|im_end\|> <\|im_start\|>assistant Hawking's area theorem applies with a positive energy condition. Hawking radiation creates a negative energy condition. Without the black hole absorbing additional mass the energy condition is negative due to the Hawking radiation, Hawking's area theorem doesn't apply, and the black hole evaporates.<\|im_end\|>
<\|im_start\|>user How did Schrodinger come up with the wave equation, if he didn't derive it? I am from India and conservative people often boast about how Schrodinger got his wave equation from Hinduism. They say Schrodinger, because he used to study Hindu scriptures, got the equation inspired from Vedanta. Now, I know this is pseudoscience, so I tried to see how Schrodinger derived it. Google search says the equation can't be derived and is axiomatic. Then...how did he make this equation? Did his mind just produce this equation out of sheer intuition? I thought maybe its like how Newton got F=dp/dt, but again, this equation is far too complex to just come out of nothing. So...what's happening?<\|im_end\|> <\|im_start\|>assistant axoimatic basically means he looked at what was measured and built an equation from what was observed. he knows he was right because his equation correctly predicts measurements, not because it is derived from other equations. F=ma is kind of similar<\|im_end\|>
<\|im_start\|>user How is it that they can X ray paintings to see what is under the picture (previous pictures o changes that the painter did)? What's the x ray stopping at? Is it the same kind of x ray that they use at hospitals?<\|im_end\|> <\|im_start\|>assistant Adding info to other good comments. The x-rays themselves would be very similar and generated in the same way as medical x-rays. However, they would be much lower energy so that differences could be seen from such a thin subject (the painting surface). The higher the x-ray energy, the more penetration. If trying to see very subtle differences in thickness and material, a lower energy would be blocked differentially by such small details and provide useful contrast. The x-ray detectors that form the images would be more sensitive or (in the case of phase-contrast imaging) count/process the image data in a different way. Besides just thickness differences created by different layers of paint, some paint pigments are mineral-based and the effective atomic number of different pigment molecule types can generate appreciable contrast, especially at low x-ray energies.<\|im_end\|>
<\|im_start\|>user ELI5: How does a compass on your phone work?<\|im_end\|> <\|im_start\|>assistant A pretty common method is to use magnetoresistance. Some materials change their electrical resistance depending on the direction of the magnetic field they're exposed to. So they put little slivers of those materials on a chip, at specific angles, along with circuitry to put a specific amount of current or voltage through the materials, and measure the how well electricity flows through them. Once they know that, the chip does the math to determine the precise 3D angle the magnetic field is pointing. The phone's CPU asks the chip for the compass data several times a second and averages it out to give you a smooth reading.<\|im_end\|>
<\|im_start\|>user ELI5: Dreams. Why sometimes the dream is so vivid that we get that "Damn it was just a dream" feeling? Trying to make it more clear: I had this really nice dream last night. And was kinda sad for me waking up to realize that I was in fact just dreaming.<\|im_end\|> <\|im_start\|>assistant You're going to get lots of 'experts' giving self-assured reasons why. But any question about dreams is like a dream itself - we just don't have confident answers yet because we don't really understand dreams well, or even the brain itself for that matter.<\|im_end\|>
<\|im_start\|>user [ELI5] why do stoves use meaningless scales on their dials? 1-6 & Hi? Low-Hi and Hi+ on the power burner? Watts or rate of fuel flow would provide an easier basis of comparison between stoves and make cooking far more consistent.<\|im_end\|> <\|im_start\|>assistant The arbitrary scales are easy to implement and easy to understand. Using a "real" unit like watts or fuel flow would take extra instrumentation and careful calibration and, even then, would not give you consistent cooking because you care about how much energy gets transferred to the food, which is extremely strongly influenced by the shape of the burner, the shape of the flames, and the cooking vessel.<\|im_end\|>
<\|im_start\|>user Why don't metal detectors go off because of zippers and metal buttons?<\|im_end\|> <\|im_start\|>assistant The detectors have a threshold setting which is often adjustable. They're detecting metal all the time, but only objects that displace the field by a given amount sound the alarm. They keep the threshold high enough that it doesn't go off for things like small zippers .<\|im_end\|>
<\|im_start\|>user ELI5 why are mercury containing amalgam tooth fillings considered safe despite mercury being extremely toxic?<\|im_end\|> <\|im_start\|>assistant The properties of elements change wildly when those elements form chemical bonds with other elements. It's why hydrogen (a flammable gas) and oxygen (a flammable gas) are not flammable when they are bonded in water, and why sodium (a violently reactive metal) and chlorine (a poisonous gas) are not deadly to consume as table salt.<\|im_end\|>
<\|im_start\|>user How did we (living things in general) evolve 2 genders? Considering that single celled organisms reproduce asexually and life as it currently exists ultimately began as single celled organisms, at what point during that evolution did life decide that having two "genders" would be more advantageous?<\|im_end\|> <\|im_start\|>assistant Note: OP didn't ask why having genders is advantageous. OP asked how life made the switch from asexual to sexual reproduction. Which I, too, would like to know. Can somebody answer the actual question?<\|im_end\|>
<\|im_start\|>user ELI5 - Can usable guns be made from titanium? I noticed during recent traveling that a titanium implant does not register with metal detectors or any other scanner at the airport. What stops people from making guns from titanium or other similar metals?<\|im_end\|> <\|im_start\|>assistant Regulations that exist that require detectable metal in the firearms for that very purpose. Titanium doesn't make a very good barrel, it expands and flexes to much. Titanium alloys have been used in the frame on certain models, but those trigger the metal detectors, not only because of the alloy material, but because the barrels are still chrome molly alloy steel. Titanium alloys aren't used in barrels for the same reason, too much expansion and flexing under heat and pressure. The same qualities that make them a great frame for aircraft and other vehicles make it a poor material choice for a barrel.<\|im_end\|>
<\|im_start\|>user I once heard a Language teacher tell me that a reason colder countries tend to be more advanced is that they have to advance their civilization and technology to cope with the cold. Are there Sociological studies supporting it?<\|im_end\|> <\|im_start\|>assistant Recommended reading: Guns, Germs and Steel. Cold countries did not really advance because of the cold, but rather because Eurasia is a huge horizontally spread landmass with TEMPERATE climate. Cold would actually be a hindrance since people do nothing in the long winter months.<\|im_end\|>
<\|im_start\|>user Why doesn't the universal translator translate Klingon? [Star Trek]<\|im_end\|> <\|im_start\|>assistant It does for the most part, but it can detect when you don't want to be translated or intentionally want to say something in another language for example when you use proper nouns, or when you want to say ritualistic or religious speeches.<\|im_end\|>
<\|im_start\|>user Intelligence Quotient / IQ, what exactly is it and what are its criticisms? Why is it potentially wrong?<\|im_end\|> <\|im_start\|>assistant IQ is a measure of how 'intelligent' you are compared to the average person your age where you live. Having an IQ of 100 by definition means that you are exactly average for your age and area. A 20 year old and 12 year old writing the same test and marking the exact same answers would get different results. The 12 year old having answered everything the same as the 20 year old would get a higher IQ because older people are expected to get more answers right than children. Similarly the test is reclibrated based on region, but this is not a big difference in practice. The result however is that the average IQ in the US is exactly the same as the average IQ in for example Pakistan: 100 because that is how the whole thing is defined. Some criticisms are based on the age thing. Some children develop faster than other which might lead to having fantastically high IQs as children which later when they reach adulthood go down to only normal 'very smart'. Other somewhat controversial criticisms are for example about the fact that IQ test are supposedly culturally biased in some way or another. Even more controversial theories attack the concept of intelligence itself and demand that it be more inclusive. Some people believe that certain other skills and abilities such be seen as forms of intelligence, that for example someone who is not good with numbers or words or spatial reasoning or abstract ideas but is a really good dancer should be considered to be 'intelligent' in that area. While there might be some kernel of a rational and worthwhile argument at the core of this theory it has been pretty much co-opted by people who use it unintelligently like parents who refuse to admit that their child has below average intelligence and insists that he is merely differently intelligent as evident by the fact that he is good at sports.<\|im_end\|>
<\|im_start\|>user is floating in water at 1g equivalent to floating in more/less dense fluid at higher/lower g? In the pool yesterday and I was wondering, could I have much the same experience of floating in the water if I were on a low-g planet? Not water - at low-g I'd think that water would push me up too much, like, I wouldn't be able to swim down as easily. So, is there some lower-density fluid that, on the moon, I could swim in and have much the same experience as swimming in water on earth? And same for a high-g planet, could I swim in something heavier and have much the same experience (though I suppose the weight of my organs etc pushing on one another wouldn't change - I'd still feel the same inside)?<\|im_end\|> <\|im_start\|>assistant What determines if something floats in a liquid or not is the balance between the gravitational force pulling the object down, and the buoyant force pushing the object up. If the buoyant force equals the gravitational force, an object will float. If it's less than the gravitational force, the object will sink, and if its greater, the object will rise. The gravitational force is simply F=mg. The mass of the object is invariant, so going to a higher or lower gravity environment will scale the gravitational force by the same ratio. The buoyant force F_b=dgv, where d is the density of the liquid, g is the same as above, and v is the volume of liquid displaced. Like the mass of the object, the density is invariant with gravity, so the question becomes does an object displace a different amount of liquid under different gravity? Following the condition that the two forces be balanced for the object to float, we can see that the gravitational acceleration cancels out and gives us a hint that gravity doesn't play a part in this, but let's keep going. F = F_b mg = dgv m = dv The mass of the object can be expressed as m = DV, where D and V are the density and volume of the object. Which brings us to DV = dv D/d = v/V Since we know the densities are invariant with gravity, the quantity D/d is a constant. That means the displaced volume of the liquid, v, will only change if the volume of the object, V, changes. So ignoring small changes in the volume if a human body under different pressures, temperatures, etc, this means that floating in a liquid or not does not depend at all on what the acceleration of gravity is. You would float the same in water under 10 times or 0.1 times the surface gravity of Earth, and only another liquid with the same density as water would give you the same floating experience.<\|im_end\|>
<\|im_start\|>user ELI5: What is the scientific purpose of landing on the comet, and what are it's implications? Besides, you know, because we can.<\|im_end\|> <\|im_start\|>assistant The purpose is exploration and the testing our capabilities. If at some point in the far future we are going to harvest comets for resources (which would be more practical for building things in space as it takes far less energy to get resources off a comet as opposed to earth) this is the first step in a long process of making that happen. Also there is basic exploration. We have never been on a comet before, therefor there is a lot to learn about the makeup and development of comets.<\|im_end\|>
<\|im_start\|>user Do stars exist that only emit infrared light?<\|im_end\|> <\|im_start\|>assistant Bodies radiate electromagnetism at different wavelengths based on their temperature. Infrared, radio waves, light, x-rays, etc. are all em radiation at different wavelengths. In order for a star to be doing any nuclear fusion it has to be hot enough to emit visible light. There are brown dwarfs which are sort of quasi stars but in short, not really.<\|im_end\|>
<\|im_start\|>user After the big bang, the universe underwent hyperinflation. Currently, our universe is expanding at an increasing rate. Can someone explain how the expansion of the universe was fastest immediately after the big bang, slowed down (?), and is now increasing at an increasing rate?<\|im_end\|> <\|im_start\|>assistant There are different mechanisms at play. Inflation in the super early universe arises when the universe is in an initial state with the fields having some value, but the vacuum can reduce its energy by a field shifting to a different value. The process is somewhat like happens when a ball rolls down an inclined plane to get to a stable minimum. This produces the exponential expansion of inflation. After that, we have a competition between two mechanisms. The universe is expanding outward, but the gravitational attraction among things tends to slow that expansion down. However, there is an additional effect -- consistent with what's called a cosmological constant term, and generally just called dark energy -- that causes a negative pressure term, which promotes the expansion of the universe. As the universe expands, the matter is denser at the beginning and then gets more spread out, so the relative size of the attractive term compared to the cosmological constant/dark energy term decreases over time. As a result, there was a period when the gravitational attraction dominated and slowed down the expansion, followed by the epoch we are now in, in which the cosmological constant/dark energy term dominates.<\|im_end\|>
<\|im_start\|>user ELI5: If the medicine in Epi-Pens degrades when exposed to light, then why is the container clear and not opaque?<\|im_end\|> <\|im_start\|>assistant The medicine itself needs to be clearly visible to the user. If it gets cloudy, or has suspended particles, it should no longer be used and just discarded. The risk of using a bad medicine is larger as it may not be effective in a life threatening situation. Thus, clear containers instead of opaque.<\|im_end\|>
<\|im_start\|>user ELI5: Why can't long cables be stretched perfectly straight? I'm thinking about electricity cables for example.<\|im_end\|> <\|im_start\|>assistant Its 3 things combined. Weight, malleability, gravity. The wires themselves are heavy, and gravity is always trying to pull them down. In order to attempt to keep a wire stretched straight across you need to put on enough tension to over come gravitys attempts to pull it down, however all metals used for powerlines will stretch if enough tension is placed on them. The amount of tension required to over come gravity is more then what the wires will tolerate before they can't hold themselves together anymore and snap. Edit: as u/OVERHEAD1 points out below, there is also the issue of expansion and contraction due to temperature.<\|im_end\|>
<\|im_start\|>user Is there a limit to how many atoms there can be in a molecule?<\|im_end\|> <\|im_start\|>assistant Depending on your definition of molecule, it's pretty clear there's no limit in a practical sense. Crystals are essentially giant molecules, if by that we mean continuous blocks of atoms connected by sharing electrons. (Blocks of metal could also count.) There's no fundamental difference between that and what we typically think of as a molecule, but the term molecule is pragmatically reserved for items that aren't arbitrary in size. (Although we do talk about DNA molecules, which can be sized arbitrarily.)<\|im_end\|>
<\|im_start\|>user CMV: There is nothing inherently racist about not being attracted to certain ethnic or racial groups To be clear, not wanting to date a black person because of stereotypes about black people ("I think black people are XY") or opposition to interracial dating is racist, yes. However, not wanting to date a black person due to not being attracted to skin colour is not racist. Most people have preferences based on weight, height, face shape, etc. Most women would not want to date a shorter man. Gay men are not attracted to women and lesbians are not attracted to men. Attraction is no more a choice than taste in food or art. I did not choose to like vanilla ice cream and chocolate cake whilst disliking chocolate ice cream and watermelon. So if not being attracted to black people or Asian people is racist, are gay men sexist? For my view to be changed, one would have to explain * How not being attracted to a certain race is racist whilst being gay is not sexist * How attraction to skin colour or other features is any different than attraction (or lack thereof) to weight or height.<\|im_end\|> <\|im_start\|>assistant Would you say that having had and still somewhat having 'white' beauty standards may cause people to have underlying biases towards dating certain races? If say, black features, are portrayed less in the media as being attractive then people are less likely to find them attractive. I would argue that that was racism of a kind, although not as blatant as other forms.<\|im_end\|>
<\|im_start\|>user [Seinfeld] Seinfeld had a considerable number of enemies, How likely is it that he was shanked in prison after the final episode? Or that on appeal the insane law that required him to rescue a complete stranger from carjacking was overturned?<\|im_end\|> <\|im_start\|>assistant On appeal it's almost certain that the law will be found unconsitutional as the number of laws that require an affirmative action you could count on one hand. Also the fact the gang had reasonable belief that the car jacker had a gun would also be an easy defense even if the law wasn't unconsitutional. They could easily get a mistrial if Jackie CHilds did such a lousy job as a lawyer that he didnt' even mention something that basic.<\|im_end\|>
<\|im_start\|>user ELI5: Why are bigger sizes of the same item of clothing the same price? Seems like you should pay more for more material?<\|im_end\|> <\|im_start\|>assistant The materials cost (especially the difference in materials cost between two sizes) is an insignificantly small portion of the cost to design, manufacture, transport, distribute, advertise, store and ultimately sell you the product.<\|im_end\|>
<\|im_start\|>user ELI5: If light doesn't have mass, why can't it escape the gravitational pull of a black hole?<\|im_end\|> <\|im_start\|>assistant According to general relativity, gravity is not a force, but the curvature of spacetime itself. Photons follow straight lines through space, but in a curved spacetime those straight lines might look as though a force is acting on the photon to an outside observer.<\|im_end\|>
<\|im_start\|>user Why does rock salt help with thawing sidewalks, yet it's used in ice cream makers to make the ice cream even colder? This is something that has absolutely confused me since I was a fetus.<\|im_end\|> <\|im_start\|>assistant Here's why: the scientific principle is identical for both purposes. Adding salt to water allows it to remain at the liquid state at a colder temperature, usually the coldest possible temperature is -25 degrees Celcius. The use is obvious for thawing snow or ice in the winter, throw it on the ground and it melts. When it's used in an ice cream maker, they don't put it in the ice cream, but on the ice around the ice cream barrel. This allows more of the water to contact the barrel at a lower temperature, thus increasing the heat transfer rate from the ice cream to the ice when making the ice cream. Edit: the temperature listed (-25) is a rule of thumb that is used when salting your sidewalk up here in Canada. If it's colder than that, it's considered a waste of time and money to throw salt down.<\|im_end\|>
<\|im_start\|>user ELI5: Why are cops allowed to be fat?<\|im_end\|> <\|im_start\|>assistant Because height, weight, and physical ability testing is done at the time of qualification—there's no ongoing fitness or ability requirement in most places. As many commenters have already pointed out, very few cops actually sprint after perpetrators all day, or ever. They mostly sit in cars or behind desks, same as the rest of us.<\|im_end\|>
<\|im_start\|>user If I were able to stand next to Voyager I where it is now in interstellar space, would I be able to see it? I was wondering if there would be enough light (photons) out there to bounce off the spacecraft and hit our retina or if it would appear to be a silhouette against a starry sky? Or dimly lit. I got to thinking about this after watching Star Trek recently and wondering if there was enough light in deep space to make the ships look so shiny.<\|im_end\|> <\|im_start\|>assistant You can easily estimate how well is voyeger 1 illuminated. Direct sunlight is about 50,000 lux. Illuminance falls with distace squared. Voyeger is 125 AU far. So illuminance is roughly 50,000/125**2 = 3.2 lux. So Voyager is better lit than open terain in the light of the full moon, which is about 0.5 lux. Even in the deep interstellar space lets say 1 ly away Voyager would be still visible, thou just barely.<\|im_end\|>
<\|im_start\|>user What makes some materials oven-safe but not microwave-safe or vice versa?<\|im_end\|> <\|im_start\|>assistant The dielectric properties of the material. In oven safe, the material has to take external heating, which will be a function of its heat transfer capacity ie if you heat it too fast, one area will expand too quickly, stressing the material and causing the break. For microwave safe, the dielectric properties describe how well the material absorbs the energy, or how microwave transparent it is. Ideally, you'd want a microwave transparent material so that only the food (particularly the water) absorbs the energy therefore heating/cooking the food. If the bowl has a high dielectric constant, then the bowl will heat, causing the bowl to crack or be at a temperature much higher than the food being cooked.<\|im_end\|>
<\|im_start\|>user ELI5: Why with today's camera technology do we still use video cameras that are 15+ pounds, and require two hands and a shoulder to rest on?<\|im_end\|> <\|im_start\|>assistant For quality and photographic properties. The biggest limiting factor is the lens. The wider the lens, the more light it can capture; and the longer the lens, the more tightly it can focus on distant subjects. Lens size is also related to other visual properties like depth of field and the compression of space. With still-photo cameras, you can use a longer shutter speed -- leaving the camera sensor 'open' for longer periods -- to acquire more light. This is not as possible with video cameras which require a minimum of 24, often 25-30, images to be taken each second; the effective maximum shutter speed is 1/24th of a second. So if you want to acquire more light you need to make your lens bigger. If you want to see the problems inherent in a small lens, go and take a cellphone photo outdoors at nighttime, and see the noise and poor detail that results. Even the best cellphone cameras struggle because it's the size of the lens that limits you. There are other factors involved as well. You need to weigh down the back end of the camera to balance for the heavy lens, so now it's even bulkier. But you actually want some bulk most of the time, because it helps you keep things steady when shooting 'from the hip' (just holding the camera, without tripods or camera mounts). If you have a camera that's 3 inches wide and light as a feather, every tiny movement you make will jostle it and make your video a shaky mess. If it's got decent heft to it, it's easier to hold it steady and avoid jostling it with minor movements, and if it's big enough to mount on your shoulder, even easier. Then there's storage. If you're just some guy filming occasional 720p clips of your friends skating or of your dog catching frisbees, then saving to phone storage or SD cards is great. But professionals have different needs. Uncompressed 4K footage is 44 GB per minute. So you want cameras that can film to hard drives, SxS, etc, and that means bulk. And you want batteries that can shoot high-quality footage and run those hard drives and powered mics for at least a couple of hours while in the field, which means bigger, bulkier batteries. These are all concerns that mostly professionals have, which is why it's mostly professionals that still have these big heavy cameras. For family movies and casual stuff you do use those much smaller, lighter cameras that can be wielded with one hand.<\|im_end\|>
<\|im_start\|>user ELI5: Why do we hold onto our injuries after we get hurt (Holding your head after it hits something) ?<\|im_end\|> <\|im_start\|>assistant It is a natural reflex to prevent the injury area from receiving additional damage. Taking an injury to our limbs is less severe than to our torso or head. Injuries are not additive but multiplicative. This means that injuries close together can cause much more complications than if they occur separately at different locations.<\|im_end\|>
<\|im_start\|>user ELI5: Why does the last bit of ice in a cup refuse to come out without me having to bang the cup?<\|im_end\|> <\|im_start\|>assistant The same thing that gives water its surface tension gives it the ability to stick to other surfaces. Each water molecule is basically a tiny, weak permanent magnet. This allows it to stick to other water molecules pretty well, but it also allows it to stick to other substances since most other substances have a tiny bit of charge, as well. However, this magnetic/sticky force is very weak (this is why some bugs can walk on the surface of water, but you can easily push your finger through the surface. So knowing all this, the reason you have to bang on the cup is because the ice is always melting (assuming you're in a room temperature environment), so the ice has a layer of water all around it and on the bottom of the cup. That surrounding water's sticky force is only strong enough to hold the smallest pieces of ice. A second piece of ice sitting on top of the bottom layer of ice doesn't have the advantage of being surrounded so thoroughly by water, so it easily falls out. tl;dr: only a thin layer of water can stick to the bottom of the cup. If a piece of ice is small/light enough, the bottom layer of water sticks to both the cup and that piece of ice, holding it in place.<\|im_end\|>
<\|im_start\|>user What is money? Can someone explain what money is? Why do we seek it? Is money just a lie that we keep telling ourselves? Also, why is money so effective in what it does? Has there always been money?<\|im_end\|> <\|im_start\|>assistant Money is a medium of exchange which we seek because we believe we can always exchange it for something that we want. Depending on who you ask, money has been around as credit since the dawn of civilization. In classic economic theory (Adam Smith) money evolved from bartering. This has been widely debunked. One of the more popular critics is David Graeber who wrote "Debt the first 5000 years". His basic premise is that money is credit and has always been credit. In the modern world, we have global consensus on the idea of money which makes it far more valuable and efficient than it has ever been.<\|im_end\|>
<\|im_start\|>user ELI5: How does U-Haul get away with having all vehicles licensed in 1 state? All U-Haul vehicles I've seen are licensed in Arizona. How can they operate in so many jurisdictions but only pay for licensing in 1 state?<\|im_end\|> <\|im_start\|>assistant There are laws pertaining to fleet vehicles - in other words, a fleet of vehicles all owned and operated by one company - that allow the company to title and license all their vehicles in the place where the company's main center of operations is located. Companies use this because it allows them to set up a single account under which all the fleet vehicles' tags are renewed at once, rather than being sprinkled on different due dates throughout the year. In U-Haul's case, their HQ is in Phoenix, AZ, so AZ fleet licensing laws allow them to title and license all their vehicles in that county. Every state has slightly different requirements for how many vehicles constitute a fleet and how fleet licensing is handled. AZ and IL are two of the more common states you'll see on big trucking fleets because they have the business-friendliest fleet licensing laws.<\|im_end\|>
<\|im_start\|>user ELI5:Why exactly do we need differential calculus? I have just started learning calculus, and I get the gist of differentiation and integration and stuff, but why exactly do we need to use it ? I mean, for example, velocity/time is already acceleration, so why can't we just use that in place of dv/dt?<\|im_end\|> <\|im_start\|>assistant It is no exaggeration to say that anything university level that requires mathematics will need calculus. In fact it is probably the basics of what you need. Things only get more complicated from there. Differentiation is basically calculating a rate of change. Turn that around and you get integration, which basically allows you to find out different things given a function, i.e. a graph. It is easy to calculate the area under a graph if it is a straight line. Once it becomes more complicated, like a curve, then it becomes more difficult. So you use integration. Many topics in advanced education begin to use mathematical models to define things. Even things you wouldn't expect. And often these mathematical models will involve the use of calculus. For example, in psychology you are often required to take statistics, which uses calculus. Even in a management class you can be given a formula which may model a market or effect of change in prices on demand. These will use calculus to find an optimal solution to something. How would that work? well we know differentiation is finding the function that defines the rate of change. How would you find the optimal solution to a function; say the profitability of a product is defined by a curved function; it goes up, then starts slowing down (i.e. curving) before going down, due to the idea of diminishing returns. What would be the optimal solution? how do you find the "peak"? well that is simple. You find the precise point where the rate of change is 0; it is the precise point from when it increases to decreases. The peak of the curve. What happens if you differentiate that profit function? you are finding the marginal profit; how much more profit you get per unit of production. What happens if you integrate that function? you get the total amount of profit. You can even use it to define the amount of profit you get at different points of the curve.<\|im_end\|>
<\|im_start\|>user Eli5 Why do some wines or whiskeys have a cork top, but others stick to a screw off top? Is this flavour based? Aesthetic? An old tradition to certain branding for no reason?<\|im_end\|> <\|im_start\|>assistant Basically just tradition and marketing nowadays. Corks have two advantages over other methods that were available back in the day of sealing a bottle: a cork creates a pretty good seal, but still lets some oxygen through. That's ideal if what we want is to seal up a bottle for a long time and have the wine or whiskey not go bad straight away, but also oxidise a little bit, slowly over time, which is what 'ages' the beverage in the bottle. Plastic corks might actually work better for this than natural corks but it's debated. Screw tops let almost no oxygen in so they're a bad choice if you want to age that bottle for 10 years. But otherwise, they're the same, and the vast majority of people buying any of these things is not going to age them long term, so it's mostly tradition and prestige to use a 'proper' cork<\|im_end\|>
<\|im_start\|>user ELI5: How do the meteorologists know what the "real feel" is? Or apps, for that matter? My AccuWeather says there's a temperature of 9C outside, with a real feel of 10C. In the winter, it showed -5C with a real feel of -11C. How is that determined?<\|im_end\|> <\|im_start\|>assistant Real Feel temperatures are typically based on a calculation that considers the heat loss (or gain) of a typical person that factors in ambient temperature, humidity, and average wind speed. These real feel temperatures attempt to estimate the equivalent "no wind" and "no humidity" ambient temperatures that would feel the same to a typical human. EDIT: clarity<\|im_end\|>
<\|im_start\|>user CMV: I think that anyone who works 40 hours a week in the USA should be entitled to a middle class lifestyle. I believe that anyone who works any job, no matter how trivial, easy, unskilled, or unglamorous for 40 hours every week in this country (USA) should be paid enough not only to rent an apartment and afford groceries every month, but should make enough that they can put a reasonable amount of money away to afford things like a house, a family, a car that works, healthcare, a retirement plan, yearly vacations, etc. I'm not saying that every Taco Bell employee in the country should be living in a mansion and driving around in a Ferrari, but I think that an average employee of Taco Bell who works full time should be able to afford to purchase a modest home and raise a family on their salary. I believe that there is enough money in this country to make that possible, and that it is a matter of poor distribution and unregulated greed that keep profits soaring for so few while the majority struggle to make ends meet. I believe that it is a mark of shame on us as a country that we have so much wealth as a nation and yet so many of our people work multiple full time jobs and still struggle to pay the bills. I believe in a hard days work for a decent paycheck, but I also believe that the reverse should be true as well. I'm not advocating everyone making the same amount of money at all, I just think that if the richest person in the country made only 100x what the poorest person did (assuming that both are employed full time) that things would run a lot more smoothly. CMV. EDIT: I'm not arguing that I have the economic answers to wealth disparity in the USA. This post was more of a reaction to the mindset of, "If you work as a janitor you don't deserve enough money or dignity to do anything more than barely get by regardless of how hard you work at it." which seems to be a fairly common sentiment here and elsewhere. I'm not saying I know how to fix it. I'm just saying I think it's wrong, and that hard working people deserve a shot at a decent life regardless of what they do for a living. It's also weird to watch people react to the idea of a "menial laborer" being able to buy a house or have a kid as this crazy luxurious lifestyle that only doctors and lawyers should be able to afford (I know, I know that's an exaggeration but you get my point). That strikes me as totally bizarre in one of the wealthiest nations on the planet. EDIT 2: I think I wasn't clear in my calling it a "middle class lifestyle". I didn't mean that the lower class would completely disappear. I meant that "lower class" in this scenario would mean "a house that was just ok and maybe if I scrimp I can send my kid to private school" like many middle class families today. I'm NOT arguing for across the board wage equality. I'm arguing that the gap between rich and poor is out of control and that if you spread it around more evenly while still giving more to those that work harder at more highly skilled jobs, things would run more smoothly. _____ > Hello, users of CMV! This is a footnote from your moderators. We'd just like to remind you of a couple of things. Firstly, please remember to *[read through our rules](http://www.reddit.com/r/changemyview/wiki/rules). If you see a comment that has broken one, it is more effective to report it than downvote it. Speaking of which,* *[downvotes don't change views](http://www.reddit.com/r/changemyview/wiki/guidelines#wiki_upvoting.2Fdownvoting)*! If you are thinking about submitting a CMV yourself, please have a look through our *[popular topics wiki](http://www.reddit.com/r/changemyview/wiki/populartopics)* first. Any questions or concerns? Feel free to *[message us](http://www.reddit.com/message/compose?to=/r/changemyview). Happy CMVing!*<\|im_end\|> <\|im_start\|>assistant It's easy to say that this "should" be the case, and it's a nice philosophical position to take, but how would you propose that this be accomplished? If someone doesn't produce enough value (as perceived by those purchasing the value that they produce) to have this standard of living, how do you arrange for this to happen? Laws and regulations by themselves (specifically minimum wages) can't accomplish this. If someone doesn't produce enough value for this standard of living, no one will voluntarily pay them this much, because it makes absolutely no sense, economically or otherwise. Ultimately, you're going to have to use force to take from one person to give to another. And that's a choice you can make. It might even be possible to argue that it's a "necessary evil", but you're not going to just magically get it to happen by voluntary interactions between people. And as others have mentioned, it's mathematically impossible to have everyone be at or above the "middle" class without ultimately having everyone literally earn the same amount.<\|im_end\|>
<\|im_start\|>user ELI5: How does basic health insurance work? Can someone please elaborate on what a "deductible" and "premium" are as well?<\|im_end\|> <\|im_start\|>assistant The basics of health insurance (or any form of insurance for that matter) is to create a large pool of people to spread risk around. You're not sick today, but you might get sick next month. You pay into a pool every month and only pull money out when you need it. The healthy pay for the sick with the assumption that they will get benefits when they themselves become sick. The premium is the price you pay every month to be part of the pool. However, when you do need health care, most insurance plans don't cover 100% of the cost. Usually the first bit of the cost has to be paid by you and the remaining gets picked up by the insurance company. That initial amount is called the deductible. For example, let's say you need a surgery and it costs $10,000. Your deductible is $500. You have to pay the doctor $500 out of your own pocket and the insurance company pays $9,500.<\|im_end\|>
<\|im_start\|>user ELI5: Why does the sun cause things to fade over time? I recently looked at the back of the curtains at my dad's house and noticed they're extremely faded, and was curious what it is about the sun that causes this type of fading<\|im_end\|> <\|im_start\|>assistant When a molecule absorbs a photon of light, it does so by jumping an electron up to a higher energy level. Dyes are typically complex molecules, so when an electron tries to come back down (by emitting some photons of its own), there's a good chance it doesn't go back where it started; which changes the chemical structure of the atom. Maybe it breaks in two, maybe the shape just changes. Either way, now it doesn't reflect light in the same way, so it changes color; most commonly it stops reflecting visible light at all. In other words, it fades. Ultraviolet light is good at causing this kind of reaction. Sunlight contains lots of ultraviolet light, but electric light doesn't contain much, which is why the window side of the curtains fades much more than the room side.<\|im_end\|>
<\|im_start\|>user CMV: If you think “not all men” trivializes the issues women face by men, then you should feel the same way about “not all immigrants”. Let me start off by saying that I think both of these statements are stupid for various reasons. I’m also not some altrighter trying to bait this subreddit so mods be nice. That’s not the point here though. On social media I often see women make fun out of men who say “not all men” in response to women sharing their stories of being harassed, catcalled, etc. 99% of all women aren’t stupid and obviously know that it’s of course not all men who do this, but it’s significant enough that they feel like it’s a story worth sharing. How about this then. During New Year’s Eve 2015/2016 over a thousand women in Germany were sexually assaulted, primarily by immigrants from the Middle East. What do people respond to this with? “Not all immigrants”. Particularly, there seems to be an overlap with the same people complaining about r*pe culture who also suddenly decide to say “not all immigrants”. So which one is it? Because you can’t say one without saying the other. You’re generalizing an entire demographic and you can’t minimize one without minimizing the other, or vice versa. Either you say “not all X” in both cases or none at all. Change my view.<\|im_end\|> <\|im_start\|>assistant The speaker and the point of the conversation are important here. In the first case, you have a woman sharing her personal story about being assaulted, harassed, catcalled and some guy making it about himself and commenting "not all men." And not only is he making it about himself, he's not so subtly accusing the woman of sharing her story as being sexist. Now your second example isn't about a personal experience is it? It's a conversation between two observers of the event, a political/social debate, rather than between a victim and a random commenter, yes? One observer who uses this story as an example to support their anti-immigration views, and another observer who disagrees with the anti-immigration agenda. In this case, saying "not all immigrants" is acceptable. This is not a person trying to drown out someone else's story, it's a person making a point in why they disagree with you about how you want to respond to immigration in Germany.<\|im_end\|>
<\|im_start\|>user ELI5: what is actually happening when you get a "knot" in your muscle? Edit: additional question...is massage the only solution? Or are there other ways to help them go back to normal?<\|im_end\|> <\|im_start\|>assistant Massage therapist here; Your muscles are made up of bundles of long thin fibres. These bundles are wrapped in a very thin membrane (fascia). When you use the muscle a lot, the fibres stick together and to the membrane. Fibrous tissue feels "lumpy" and that's what you feel when you touch it. So it feels good when someone massages it, because it breaks up the fibrous tissue buildup.<\|im_end\|>
<\|im_start\|>user CMV: “Objective quality” does not exist in art. I’m a musician, so I hear this kind of talk a lot, from fellow musicians and non-musicians alike. When I share a piece of music that I like, I often hear “this is shit,” or “this other song is so much better,” and even positive reactions such as “this is so much better than that dubstep garbage!” And so often, I hear that terrible, terrible word... “Objectively...” There are things that you can say objectively about art. You can tell me what key a song is in, or what kind of paints were used on a canvas. But I really don’t see how you can ever speak objectively about the quality of a work. Art is, at its core, about the individual’s reaction to it. It is based on emotion. There are no quantifiable measurements that can determine if something is good or not, or better than something else. Now, I agree that there are often cultural standards by which we judge art. A Monet painting is generally considered to be better than a stick figure. But is that because of some innate quality within it, or is it because we have been raised in an environment that teaches us a preference? Someone who grows up listening to rap will probably think that rap is better than jazz, for instance. As further evidence, entire artistic movements throughout history have been dedicated solely to destroying these standards. Dadaism and the music of John Cage are conspicuous examples. These movements were never about making “bad” art, but rather art that doesn’t fit the societal standard. I guess the summary of my belief is that elitism is dumb, because there is no objective measure of quality in art. I think people need to recognize that if they don’t like a piece, it’s not because that piece is bad, but because they have not had the cultural background needed to appreciate it. Anyway, let me know what you think.<\|im_end\|> <\|im_start\|>assistant You're trying to grade art objectively on a scale of "good/bad" which is a paradox- an objective measure of a subjective scale? Objective taste? Obviously that's an oxymoron. However, there are plenty of other scales you could apply to a work of art. In a performance piece like singing or playing an instrument, you can objectively measure how close a human is to accurately producing the correct notes and the correct timing for the sheet music which is objectively written in ink. For a painting you can objectively measure things like how precise someone's brush strokes are (think here precision sign makers, calligraphers, people who copied books by hand looking like print in the medieval period). In film you can objectively note things like how clean the audio sounds (is there a ton of clearly unintended hiss, pops, distortion etc...?) poor use of the camera and light resulting in blown out images, etc.... There are ways to objectively, not just subjectively, compare the production values that go into a piece of art which separates works with the quality, experience, and motivation of a high school class project versus a professionally made work of art.<\|im_end\|>

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