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How do diamond tipped tools wear out?
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Diamonds have a high hardness (resistance to scratching) but only a middle of the road toughness (resistance to impacts). A negligible impact can cause them to crack chip or even shatter. The other culprit is heat. Diamond tools remove material by scraping a very thin layer off creating a lot of friction. Friction of course causes heat. Since diamonds are such good conductors of heat this means in most circumstances all that heat is transmitted to the material they are embedded in. Sometimes this causes the material to crack and the diamonds just fall out sometimes the material that is being cut or even the material from the tool softens and glaze over the diamonds so they are no longer the cutting surface. In extreme cases of misuse the heat can cause the diamonds them self to crack. Proper application of coolant and speed/feed will reduce these effects.
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Yes, actually. The cutting and polishing tools have diamond tips (made from lower-grade, uglier diamonds).
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Why do so many recipes not add salt to meat before it's cooked?
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Because they're wrong and your mum was right ;) Salting the surface of a piece of meat before cooking draws out a little superficial moisture. However, this doesn't dry out the meat, it just allows the sugars on the surface of the meat to caramelise more readily - leading to a more flavoursome hunk o' beef/lamb/chicken/ocelot. The only exception to this I'd make would be braised dished where the cooking liquor will be heavily reduced to make a jus or glaze. In that case, the salt will concentrate to an unpalatable degree.
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Salt performs a number of functions; it unlocks the aromatic compounds in foods, reduces our perceptions of bitterness, enhances sweetness. All of which enhance the overall flavour and subsequent enjoyment of food. Salting foods (in various concentrations for varying amounts of time) prevents the protein structures in foods from releasing water and drying out as quickly, making for moister textures (specifically meats, but also applicable to other types of foods). Cooking in salted water also encourages food to maintain its nutrients. Source: Salt, Fat, Acid, Heat - Samin Nosrat
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Do waves move faster then light because of the sinusoidal path they take?
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Light "waves" do not move sinusoidally. This is a convenient way of representing light's wave-like properties, but they don't actually slew ftom side to side like an old truck with a sloppy steering box.
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No, they don't 'travel' in a sine wave. Rather, if you take a sound wave, and you measure the air pressure along its path, you'll notice that you will measure a sine wave in pressure. Similarly, for light, if you measure the electric field along the path of light, you will measure a sine wave.
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What do you think was behind the fainting couch aspect of Victorian culture? Were women more delicate then?
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I actually know this one! Women were generally weaker, physically, because of corsets: since corsets were laced up tightly from an early age, women's spines and back muscles couldn't support them very well, especially when they weren't wearing the corsets. As /u/aNonSapient said, societal expectations discouraged women from eating a lot, and corsets prevented it. Also, you're right about the inability to breathe deeply in extreme cases of corset-tightening. Finally, the sensibility and melodrama that encouraged emotional swooning went in and out of fashion during the Victorian Era, IIRC. However, we do tend to overestimate the amount of swooning that went on. Social etiquette required a "stiff upper lip" in the face of emotional difficulty, but I can imagine how shock + physical weakness + lack of proper nourishment + inability to breathe deeply enough = fainting.
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What you fail to recall are the sword polishing scenes in *Sir Gawain and the Green Knight*, the abduction of a virile young man by Marjorie, Countess of Carrick, and a whole slew of medieval rumpy pumpy of the "How about I show you my jugs, they're quality French slipware" variety. There was a bit of a rewrite of women's roles from the Victorian era onwards and that filtered image has coloured your 'recollections'.
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How can someone be over qualified for a job?
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Well, imagine you have a Ph.D and you're applying to work as a cashier at my coffee shop. We both know that you don't actually *want* to work as a cashier; as soon as you get a better offer, you'll quit immediately. So why would I hire you over this college dropout I know? She's smart, but she's not nearly as likely to get a better job and quit. More importantly to me, she is less likely to feel like the job is beneath her, so she'll let me push her harder.
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Because it's very hard to prove how skilled someone is in their field. Also, the people conducting the interview might just not be good at figuring out who's the best person. An interview process is an easy fall back which people know works to a certain degree. You'll often find better places will try to work out how well you can do the job, but it's easier some places than others. Also, there's certain unwritten rules in interviews that someone's going to be trying their best. If someone can't arrive on time or dress smartly for the interview, then it might suggest they'll have trouble showing up on time dressed appropriately when they're hired. Often interviewers are just trying to make their job easier by whittling people down and anything which helps them do that is something they want to go for.
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the differences between existentialism and nihilism
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Existentialism in a nutshell: "There is no *intrinsic* meaning to life, each human must find their own truths to live for and make life worthwhile." Nihilism in a nutshell: "There is no intrinsic meaning to life and there's no reason to even search for purpose, because no such thing exists. *Nothing* has a point or a purpose."
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There are different forms of nihilism. The most commonly examined is 'existential nihilism' which basically states there is no intrinsic value in life. Simplified, the universe exists. In that universe, you come to exist, not because you are meant to, or supposed to, but just because it happens naturally, like bacteria growing on old food, and you will eventually die, and that this event is essentially insignificant with respect to the universe. Hence, all meaning we draw from life is invented by us. Your life has no real purpose or result of significance in the totality of things. There are other concepts of nihilism, which posit that knowledge is impossible, or that reality is false, or that morality does not exist. It is a broad topic. The unifying theme however is that some aspect of what we consider 'meaningful' either is not truly meaningful, or does not actually exist.
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I understand that acquiring Zika while pregnant is bad. But other than that scenario what is so nasty about the virus? Does it stay in the system and cause fetal damage later or is it basically a bad flu strain?
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Like many other arboviruses, it causes problems throughout the body. Some neurological damage, including partial and transitory paralysis, and maybe there are things about it we don't understand... _yet._ It was a decade after we first saw West Nile that we understood it did damage to the kidneys, and we only recently understood that some people still express the virus (edit: or at least viral RNA) in their urine years after apparent infection. These viruses do odd things in the body. Dengue, which is related, can cause hemorrhagic fever. Some go for the meninges. Some kill off the liver and give you jaundice. Most of them cause some sort of lingering arthralgia in at least some portion of infected people. (Even after the virus is apparently gone - hope you didn't like your knees.) In other words, we just don't know yet what the long-term effects are - problems with fetuses are just the most fantastic, because babies.
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No, I believe the mother may produce immunity to the virus, including a type of antibody called IgG. IgG may pass through the placenta and provide the baby with transient immunity while in utero. After the baby is born however, it will no longer be provided with this passive immunity, and will need to complete development of its own immune system (usually around 3-years of age) in order to develop immunity to environmental challenges. Ever notice that kids are sick all the time? Well, it's because their crappy immune systems are still getting a hold on the chaotic, microorganismal world around us. As an aside, this is one reason why breastfeeding is so important. After a baby is born, it is without immunity to enormous numbers of potentially dangerous pathogens. A mother's breastmilk contains large numbers of antibodies that may be passed from mother to child. This allows the duration of passive immunity to be extended, and increases healthy development of the child.
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Why do we get goosebumps and does it "help" humans
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My understanding has always been that goosebumps are a mechanism through which the hair that *used* to cover our bodies was made to stand on end, making us look larger and more threatening and thus less likely to be attacked by whoever or whatever was making us feel on edge.
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Goosebumps are basically the result of evolution. Humans used to have a lot more hair, so getting goosbumps would puff up the hair to create more insulation and pockets for heat, like a bird that puffs up its feathers. So basically, goosebumps used to equal heat. Now we're mostly hairless it's not as necessary, but shivers and chills still get your muscles moving, so a slight increase in internal heat.
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Isn't threatening to revealembarrasing videos of people for money extortion? How are people not prosecuted for it?
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It is indeed extortion and illegal. Many people end up going to jail for it. For example, [Autumn Jackson](_URL_0_) was sent to prison for trying to extort Bill Cosby.
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It's one thing for a police department to arrest someone while they are trespassing. It's quite another for a local police department to turn a video into a full length investigation, spending resources to analyze the video, track down the trespassers, and then charge them for a petty crime. It's a huge waste of resources to stop something so minor from potentially happening again.
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If all the satellites currently orbiting the earth were left unattended, how long would it take them to crash back down to us, and what would be the contributing factors leading to their downfall?
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Low orbit satellites (most of them) travel in what we call "vacuum", but it's not really a perfect vacuum. There are still some particles out there that slowly but surely slow them gradually, also you have the effects of gravitational bumps caused by an uneven distribution of mass (northern hemisphere, for example, "pulls" more than southern hemisphere; or big accumulations of mass like mountain ranges). In general, satellites gradually slow down and require external thrust to correct their trajectories from time to time. When their fuel runs out, they gradually lose their orbit and "eventually" fall from orbit. This could take months, years or centuries depending the altitude and many other factors. Even high orbit satellites experience these inconveniences, but much less pronounced as you might expect.
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It varies - satellite has too much latency, the actual time delays induced by satellite connections would cause problems with the timing. There are really two options - either a wired connection, or a point-to-point microwave, where the backhaul network is daisy chained off one or more upstream sites; you can sometimes recognise these wirelessly-linked sites by the presence of a small white microwave dish. It's not uncommon for sites with the microwave link to be knocked out of service when a tree grows or someone constructs a building in the middle of the link, either needing the tree to be cut back or for the link to be replanned. If there's a daisy chain with multiple sites, a link failure higher up in the chain can knock several sites out.
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Why do old fashioned projectors show 1 whole image?
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The frames are simply images on a moving strip of film, but the image isn't projected continuously. The projector has a [shutter](_URL_0_) and [intermittent mechanism](_URL_1_), so you don't actually see anything while the frames are transitioning. The actual process for the frame would be 1) Advance frame 2) Open Shutter 3) Close Shutter 4) Repeat All of this happens in 1/24th of a second, which is fast enough you can't detect the light continuously flashing. If you didn't combine these mechanisms, you would just see a mess of combined frames on the screen.
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They're 2D images which means they look the same no matter what your viewing angle. This contrasts with your usual everyday experiences in a world that has 3 spacial dimensions. Because of this photos can give the impression that the eyes are tracking the person looking at the picture.
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So what have people thought of rainbows throughout history?
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Greeks had the goddess [Iris](_URL_0_ and I believe the Australian Aborigines believed in the Rainbow Serpent, a snake in the Dreamtime that carved out the land's rivers and mountains. I think a few other cultures had some variation of the Rainbow Serpent, including West Africa, China, and Scandinavia. I thought the Egyptians had a rainbow goddess too, but apparently not.
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Technically there are. Each droplet acts as a prism, separating the colors. From your perspective you only see a fraction of that light from each raindrop. The full rainbow effect is caused by seeing slightly different perspectives from millions of different raindrops. One raindrop gives you red light, while another raindrop (at a different location) gives you green, and another refracts yellow, etc.
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why do some roads and buildings takes AGES to complete sometimes?
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They are under construction constantly because of heavy use. I live in one of the busiest crossroads in the country and out interstates are constantly under renovation. Roads are hardy, but they still need upkeep. Another thing is that construction companies often bid on these jobs to get the contract. This means companies want to lock in contracts for length to avoid multiple bids and to ensure a good working season. Miami probably has a better working season than where I live due to weather, but it is the same idea. My uncle worked as a foreman on 2 jobs here. He spent almost 10 years on those jobs. Building a bridge and renovating a stretch of interstate.
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A lot of cities are older than the automobile. You also have nature that gets in the way of things sometimes. I would expect a city on a flat plane with no rivers that was founded after 1950 to have a nice grid system.
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Are all tetrahedral molecules non polar?
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It's more about the symmetry of the charges than the geometry that determine whether something is polar. For example water is bent and it is polar but it's not just the fact that it's bent that let's you say aha its polar. You need to consider electronegativity. Oxygen's electronegativity is much higher than hydrogen's. That means oxygen is partially negative because it schlorps some of the electron density from hydrogen. That leaves the hydrogen's partially positive. Thus when you look at the bent shape you see the ends are positive and the middle bit is negative. If you draw a line through the negative charges and then draw a line through the positive charges you can clearly see the polarity vector goes from one of these to the other. Thus water is polar.
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Geometry. Electrons exist within orbitals around an atom which have some pretty counterintuitive shapes, not just hollow spheres. When a carbon atom forms four bonds, the orbitals in which each of those 4 bonding electrons are found need to hybridise, or mix. Because of the symmetry of these orbitals, this leads to four bonding sites in the shape of a tetrahedron around the atom. It’s easy to match up three corners on a tetrahedron with 3 corners on an identical tetrahedron, but there’s no way to join the last two corners.
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Why does a dog cock its head to the side when confused?
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I believe it is because it is easier for an animal with ears on each side of its head to localize sounds in a horizontal plane. If there is some mysterious sound they are trying to learn more about, it's hard for them to know how high/low it is without changing the orientation of their head.
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That is a very interesting question which goes way, way back into our evolutionary history. One of the more compelling theories I have heard is that it comes from very simplistic organisms which would be reacting to food being detected near their head/mouth. If the food was detected to their left then their motive organs (flagellum, etc.) on the opposite side would need to be triggered in order to turn the organism toward the food. That general pattern of nerve pathway then was established and remained the template for all later evolution.
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Why was Paul Ryan seated beside Joe Biden during the SOTU Address? (not American asking)
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Paul Ryan is the Speaker of the House of Representatives. As Vice President of the United States, Joe Biden is the President of the Senate. The presiding officers of the two chambers sit behind the President, where presiding officers normally go.
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Biden could have also been referring to a previous [VP debate](_URL_0_) from the 1988 election. In this debate, Democrat Lloyd Bentsen said to Republican Dan Quale "Senator, you're no Jack Kennedy." Quale alluded to similar characteristics between himself and Kennedy in various stump-speeches. Bentsen thought Quale was thinking too highly of himself by making this comparison and was trying to deflate Quale's ego.
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If you pass a cop speeding and he follows you, then a second cop notices you as well and follows, can both issue a ticket?
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I'm not an expert, but I believe I may know the answer to this. Both cops can issue you a ticket, but you end up in court fighting the second one as a case of "double jeopardy". Double jeopardy basically says that once you've been tried for a crime and you have been legitimately convicted or acquitted you cannot be tried for the same crime again. So in all likelihood you would pay the first ticket, and argue that you are being put through double jeopardy in a separate court case against the second ticket.
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It's very rare but I did it a couple of times when I was an officer. You drive up to the side of one and wave them over then pull over the second and wave for the first to come closer. But....in general if a cop looks like they have two people pulled over.... It's almost always a collision and not because they were pulled over.
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Why do some flavors seem to blend together to make one unique flavor (think pb+j) while some flavors even when combined just taste like two separate flavors and don't work well together?
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Besides a general “taste,” flavours also have an “intensity.” I would imagine two medium but different flavours (salty peanut butter and sweet jelly) go well together, or even one intense and one light flavour. But two really intense flavours with different tastes would clash and cause the brain to perceive an unpleasant sensation.
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It's an acquired taste and it requires a fair bit of learning before you get it. It's not like normal tastes, it's not like a lemon tasting like lemon. It's really hard to explain, but it amounts to trying to look beyond the first, strong flavor and experiencing the nuances behind it. The reason it's so hard is because cigars, whisky, wine and the like have very strong "first hand flavors" that easily cover up the nuances, but once you start learning it becomes second nature to ignore that and find the subtle flavors instead.
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The Draft/Conscription in the United States
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There is no draft currently. Currently every male upon reaching the age of 18 they are legally required to register for the draft. That registration puts their name on a list. Should the draft be activated they will start going through that list in a set order and call up people. When you are called up you will go through a medical, psychological, and mental aptitude test. If you fail any of these you are exempted from the draft. If you score exceptionally well in the mental aptitude test you can qualify for Officer training, but most of the time draftees are non-commissioned personnel. You can also get officers ranks if you are drafted and have a college degree already, or if your skill set is such that your role would require you having a higher rank to function. (seen with drafted doctors, or nuclear technicians). Draft Dodgers are those who physically hid, often by fleeing the country to avoid being drafted.
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As a followup: I've heard that some women opposed their own suffrage in the US out of fear that they would also be required to sign up for DRAFT. Was this ever a serious concern? Did any legislation attempt to tie certain rights to the DRAFT?
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What if you cut the Planck length in half? Does physics break down at that point?
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The Planck length is not a universal pixel size or some kind of minimum length scale, it's just a really small length constructed from physical constants, that is roughly the length-scale at which quantum gravity effects are relevant. Depending on how you phrase your question (it is currently equivalent to "what if you cut a meter in half?" the answer ranges from nothing to creating a black hole. _URL_0_
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People do speculate about 'absolute short' -- _URL_0_ -- but it's not really a mainstream idea. It's really not clear that the Planck length has any special significance beside being a convenient unit of distance for theoretical physics.
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How much angular momentum does blood flowing through the aortic arch have?
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I don't have numbers in front of me, but determing the volume of the aortic arch, determine peak flow, find mass of the blood in the aortic arch at this time, determine velocity, and you should be able to calculate angular momentum and any resulting gyroscopic forces. i would wager that the pressure differential between the heart and the rest of the body is more than enough to overcome any forces imparted by movement. That said, a person's movement certainly has some effect on blood pressure throughout the body, an easy example being when you stand up too fast.
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Not a medical professional or anything, but I'm a mechanical engineer that works in fluid mechanics. Reynolds Number is ρuL/μ , where L is the characteristic length. Approximating flow through a blood vessel as pipe flow, the characteristic length would be the diameter of the "pipe". As the aorta is a bigger blood vessel than ones in the brain, this would make sense that the aorta would have a higher Re.
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What does a Historian actually do?
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A person with a degree in history - if it's high enough - can do whatever requires knowledge of his specific field. I've known a couple of middle east historians who used to be special advisers for certain intelligence units in the army. A person with a degree in history can also become a cultural attache in an embassy. Additionally, people who studied history learn critical thinking skills, which can be applied in various situations. A *historian*, however, is someone who specifically studies history for a living. They're usually lecturers in collages and institutions, and their job is to research. So other than giving lectures to students, they mostly research and publish articles and books about their chosen field. Just like any other theoretical academic, a historian's job is to widen the pool of knowledge regarding a specific topic, converse with other researchers, and publish conclusions accordingly.
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To my mind, a historian is one who not only studies history, but makes original and critical arguments about the history and historiography in question. You could read every history book in the world, but I wouldn't call you a historian unless you had produced some original historical argument of your own. Beyond that, it's obviously a gray area, with questions as to whether formal studies, publications, or degrees factor into the title. But I would say that if you write history, and historical analysis rather than historical summary, than you qualify as a historian. Whether you're a *good* historian or not is another question.
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What is the nuclear proliferation treaty and why do India, Pakistan and a few others refuse to sign it?
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The nuclear non-proliferation treaty says two important things: 1. All countries have a right to research and develop nuclear technology for peaceful purposes, and the more-developed countries should help them. 2. The goal for the entire world is global nuclear disarmament, the permanent abolition of nuclear weapons. Until then only China, Russia, the US, the UK, and France may possess nuclear weapons and they must make gradual efforts toward dismantling their arsenals. India thinks this is unfair, because China has them, and China acts fairly aggressively towards India sometimes, meaning India wants nuclear weapons to defend themselves. Pakistan also has disputes with India and felt threatened that India had them, so they created their own. Signing the treaty means they can't have them anymore, so they refuse.
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The nuclear nonproliferation treaty recognized the then-nuclear states as legit, and called on them to disarm to some degree (which they haven't) and tried to prevent nuclear capability from further spreading. It's called, creatively, The Treaty for the Non-Proliferation of Nuclear Weapons (NPT) of 1970. Edit: India is not a signatory to the treaty, North Korea un-signed it, I believe. It permits Russia to have their weapons. Russia, France, the U.K., the U.S., and China are all permanent security council members with vetoes - that means that any of them can unconditionally strike down any legislation from the U.N. that they don't like.
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Explain LI5 Noam Chomsky's core views on language.
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There's a big debate in the study of language as to whether people are born with certain rules and expectations about how language work already wired into the brains, or about whether infants and children simply pick up rules from hearing language used around them. Chomsky is the most famous linguist arguing for the ideas that human brains are hard-wired with certain rules and expections for how language will work. Babies and children hearing language being used around them and fit what they hear into those inborn rules (what Chomsky called "universal grammar.")
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Chompsky points to the fact that no one ever sits you down as a child and says "verbs work like this, sentences work like this..." the way we do with math and such, but all kids learn language perfectly. Because of this, Chompsky believes that out brain has a set of grammar which we are born with, like settings on a new computer. When we hear our native language, it changes the "original settings" to the rules of the language we hear. Like, your computer needs a default font setting, and you set it when you boot it up for the first time, hearing your language for the first time tells your brain "Hey verbs conjugate like this". Hope that helps with Chompsky's stuff.
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Important 30 Years War extant German sites?
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Well, the Problem with the thirty-years war is, that it isn't easy to grasp archaeologically so there aren't many museums dedicated to it. Probably the best documented battle from an archaeological point of view is Lützen and I know they have a museum there. I've never been, though, so I can't guarantee that it's large or even worth a visit. The same goes for Nördlingen, site of another important battle and a museum. You might get lucky in the [Bayerisches Armeemuseum](_URL_0_) in Ingolstadt. Not terribly far from Munich and well worth a visit. If I have the time tomorrow I might be able to write a longer post with more general recommendations (focussed on Southern Germany, because that's where I live) but I can't promise it.
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What were some major military developments in Germany, Italy, England etc. like around the same time?
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Why does acupuncture work?
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There is no sound evidence suggesting that acupuncture works for anything other than as a placebo.
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In general, it doesn't. There has been no scientific proof that it works in the manner that is classically described (Qi, energy meridians, and so forth). However, many people have found relief for various medical issues because of acupuncture treatments. There are many reasons for this, usually attributed to conditioning and the belief they are being treated. It has been shown that "fake acupuncture", that is to say, needles stuck into various body parts in non "official acupuncture points" by non-trained people was as effective as "real" acupuncture. So, getting poked by a sharp needle may trigger some placebo effect, but there is no proof that the formal practice of classic acupuncture actually does anything directly.
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Why are Autistic Spectrum Disorders far more prevalent in males than in females?
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There have been studies done recently that look into the possibility that girls with autism display the symptoms differently and have differences in brain structure leading to under diagnosis and mistreatment. [Here is one write up] (_URL_0_)
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I know Autism is linked to the age of the Father. _URL_0_
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Why do people say cigarettes keep you skinny?
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Cigarette smoking suppresses hunger. A lot of times people want something to eat but go have a smoke instead and end up skipping a snack/meal. Therefore, weight gain is usually a byproduct of smoking cessation.
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Presumably because fat is often conflated with ugly. When you tell someone that they suck because they smoke, you're judging their unhealthy habits. When you tell someone they suck because they're fat, you're judging both their habits and their attractiveness. Being called unattractive is much more insulting than being told that your habits are unhealthy.
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At what point did people realize that there's no air in space?
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Hi, not discouraging others from answering, but to get you started, see these earlier discussions * [How did scientists discover there was no air in space?] (_URL_0_) featuring /u/florinandrei * [When did humans learn or figure out that there wouldn't be any atmosphere for them to breathe in space?] (_URL_1_) featuring /u/belisaurius
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Did we know Earth's atmosphere didn't go on indefinitely before we launched our first probes into space?
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Why is Western classical music perceived as stimulating and good for brain development but not other music?
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Pretty sure this was disproven a long time ago, and it was the fact that, at one point, babies who were exposed to classical music had attentive, educated parents and the class advantage that derives from coming from an educated and affluent family in western society. It’s all just cultural bias. Just spend time with babies, talk to them a lot, and provide for them a stimulating environment (an aspect of which is just about any form of music). The time invested into babies and making them feel wanted, stimulated, and secure is what matters at that age,
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You're assuming that the enjoyment of music is the purpose of an evolutionary advantageous skill, but it's actually probably just one (of many) applications of an evolutionary advantageous skill. The skill is *pattern recognition*. Early agriculture was made possible by our ability to recognize (seasonal) patterns. Our ability to hunt specific species is dependent upon our ability to recognize a pattern of behaviour. Our ability to learn to read and speak a language is dependent on our ability to recognize patterns. etc. Bear in mind evolution *doesn't* fine-tune organisms and traits for specific needs and purposes, and oftentimes certain evolutionary traits are favoured because they are advantageous in specific situations but can be useless or downright ridiculous in other situations.
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Colonization of Venus
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As I recall, the theory was to use balloons of some sort to keep one aloft amongst the clouds. The big problem was corrosion, something that I have yet to read a solution for. I'm actually curious about what one would do for food, colonial expansion, the initial costs to doing this, and harvesting resources from Venus so as not to rely on sending supplies from Earth. I would put the colonization of Venus as possible, but not probable.
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Venus had a surface temperature in excess of 460°C (860°F) and atmospheric pressure 90 times that of Earth. Those conditions combined with high acidity means that any probes sent to Venus to explore for potential historical microbial life would likely not last long. Scientists speculate that some parts of Venus's atmosphere may contain microbial life, but Venus's conditions were never able to support any type of complex life. Also, one of the reasons for our exploration of Mars isn't necessarily to find evidence of life, but to study it for colonization. There's no way in hell we'd be able to colonize Venus, so there isn't as much value to it.
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How webhosting works.
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The internet is a collection of computers that talk to each other. When you view a website you are actually talking to a specific computer or computers somewhere in the world which has a collection of usually images and the code that makes the website format. A webhost is a business that provides computers for hire that are optimized for showing websites to people very efficiently. They handle all the hard parts of making sure when someone goes to a specific address your website is shown to the person. The cheaper web hosts provide whats called a shared hosting service. This means that you share a hosting computer with potentially hundreds of other people. This makes it very cheap to host a website as the cost is shared. I was going to write a disclaimer about how I've given an extremely simplistic answer, but then I remembered what subreddit this was.
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Web servers are just computers connected to the internet that have someone's (or, more likely, many peoples') website files on them. They have special software that sits and listens until other computers (like yours, for instance) ask for one of the websites they host. Your browser (Google Chrome, Mozilla Firefox, Microsoft Edge, etc.) is another piece of specialized software that knows how to ask these web servers for some of their data. When you type in _URL_0_ to your browser, a massive internet "traffic directory" called DNS tells your browser which web server out on the internet has the files for _URL_0_. Then, your browser uses that address given by the DNS and asks the correct web server for the data - and the server sends it over! Your browser takes that data and (usually in a matter of fractions of a second) assembles the web page for you to view.
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A teacake was launched into space, why didn't it burn up or melt on re-entry?
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Re entry is something that's only needed if you get into orbit. Orbit is when you're moving around the planet so fast that you're falling at the same speed the Earth's surface is curving away from you so you stay up there. That's why they still describe orbit as being in freefall. To do that you need to be going fast. Like multiple km per *second*. What that tea cake did was go straight up and straight back down again. Nowhere near as much speed involved. So you don't need to do the be-your-own-meteor re entry part to slow back down.
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The heated fuel expands rapidly, and is forced out of a nozzle as it expands and forces the epanding gas out. As it is forced out, the gas also exerts its force onto the shuttle (rocket, whatever) in an equal and opposite reaction. Check out this "How stuff works" on rocket engines. Its not the "fire" doing the work exactly.
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when telephone communication was in its infancy and they ran wires to connect all the telephones, how did they connect overseas calls?
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In the earliest days, transatlantic communication over the phone was done via radio tower (and later microwave towers). They could have laid a cable, but the distance was too long for the technology at the time to give the voice signal enough strength to make the distance. There were other shorter undersea telephone cables laid elsewhere in the world, but they were much shorter distances. However, by the 1950s the tech was there, and a transatlantic cable was run. It didn't carry many calls, but it was there. Eventually this improved, drastically, and now there are plenty of fiber optic cables carrying all sorts of data underneath the ocean.
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Until the 1960's, out in rural areas people shared phone lines in a system called 'party lines', sometimes as many as 8 neighbors on one line. When a call came in, there was a different ring pattern for each house, like long-long-short, or long-short-long. Gossips or busy bodies would quietly pick up the phone to listen in on neighbor's conversations.
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Why doesn't the sport of boxing sign an ESPN TV contract and stop doing PPV?
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ESPN does show boxing routinely on their Friday Night Fights. For the larger fights however, like a Mayweather bout, it is far more profitable for the promoters and the fighters to have the fight on ppv. In his last fight alone, Floyd Mayweather stood to earn over [$100 million with a bulk of those proceeds coming from pay per view earnings.](_URL_0_) TL;DR: While it might help the sport's popularity to have big time fights be shown on cable and not on a ppv basis, with the amount of money that ppv generates for promoters and fighters, that model is not going to change anytime soon.
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Because boxing and MMA have a far smaller audience, and can't be supported by advertising revenue in the way that the large mainstream sports can.
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How did the Middle East go from a free society where woman were able to wear whatever they wanted to what it is today?
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The whole history of the Middle East is too big for an ELI5 question, and there is no single answer for the whole region. Iran and Iraq are very different, for example. Iran was a fairly liberal country until the Islamic revolution of 1979, after which Islamic law was enforced. Even after that, though, Iran is not as harsh on women as other countries: dress codes are strict, but women in Iran have careers, take part in sports, drive and even race cars, vote in elections and even get elected to government office. That's not the case in Saudi Arabia, where women have been basically treated like naughty children since before the founding of the Kingdom. Daesh (ISIS) has its own rules, contradictory: they have female soldiers, but also sex slaves. In short, it's not really accurate to generalise about women's rights in the Middle East.
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Because wealthy women were often dressed by their maids, while men usually dressed themselves.
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Why does it take 2 seconds to register a purchase, but so damn long to get a refund back?
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The monetary transaction itself takes just as long in both cases. The question here is, how long it takes for the company to *want* to effectuate the transfer. When you're buying, you already decided what you want to buy, so you make the transaction, and the company already has an automated service that gives you the product based on the transfer (in case of online products, orders, etc.) - this all happens on some computers, it's fast. In case of a refund, the process is not automatic. Some employees will have to determine if the refund is "accepted" by the company policy, and companies really don't want to give money back, so such a process often takes a lot of redundant logistical steps hoping that clients just get discouraged and leave the money there.
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If someone doesn't sign and then claims they never made the purchase, the store won't get their money. Some stores have decided the amount they would lose from people not signing is less than they lose by slowing down the registers.
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If I combine a cup of water that is 30° Celsius with a cup of water that is 10° Celsius, will the resulting water combination be 20° Celsius?
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If the mass of 30° water is equal to one of 10° water, then the answer is yes. Edit. Sure, this is incorrect in precise consideration. The amount of heat a body supplies (or obtains) while its temperature is changing is proportional to its heat capacity, mass and difference between initial and final values of temperature. In the case of the problem considered the masses are equal but heat capacities for both pieces of water slightly differ, so temperature increments should differ as well. However the actual difference is very small and the obvious decision is to neglect it. Otherwise one should also take into account many other neglectible factors most evident of which for me is evaporation.
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Approximately yes. The total internal energy of the water would add, according to conservation of energy. If you graph internal energy per mass vs temperature, it's very close to a straight line between 50F and 100F. However, a cup of 100F water is *slightly less water* than a cup of 50F water. This happens because water expands with temperature (at least above 39F). I would expect (not looking at the tables, just guessing) that the water would be slightly cooler than 75F.
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Why was only landed men allowed to join the roman army pre-Gaius Marius?
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Quite simply, because pre-Marian soldiers were levied men expected to provide their own equipment for the duration of their service. Armor and weapons are expensive, and men without economic support would have an extremely difficult time providing the required equipment. The poor were often levied as skirmishers, but not as the prototypical heavy infantry that formed the backbone of the legion.
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First, I am an enormous fan of the Rome Total War series. In that context, legions are far superior to "old" Roman troops. However, I would caution against using the Total War series as a good source of historical information in general. The Marian reforms, instituted by Gaius Marius, effectively created the "new" armies. The biggest changes were the opening up of the armies to the Roman masses, greatly increasing the manpower pool, and the creation of a standing army. Marius also made legionnaires carry all equipment on their backs, greatly increasing the mobility of the armies. a To answer your question, your friend is probably right. Because the standing army could train year round with a regular and intense regimen, they likely were in much better shape physically. (_URL_0_) (_URL_1_) (_URL_2_)
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How does a computer write information onto a blank CD? What structure does the CD have to allow it?
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"Blank" CDs (CD-R/RWs) have a special alloy (mixture of metals) that can be in a crystalline state that is reflective or an amorphous state that is not reflective. When writing to the disk, the drive uses the laser to heat spots on the disc to about 700ºC. This changes the alloy to its amorphous (non-reflective) state and it will be read as "0." The reflective areas are read as "1." Heating the areas to a lower temperature of 200ºC melts the alloy, but allows it to reform its crystalline reflective state. So by variously heating the tiny spots on the disc, the laser can write 0s and 1s to the disc. :)
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Moving the file to the CD tell your computer that you want the file "burned" on to the disk. The process of burning is actually done by a laser. The laser writes the data to a thin metallic film inside the middle of the cd. If you flip a cd over and look at it carefully before you write the data the metallic film is all one color. After the cd has data written you will see the color has changed. I hope this helped.
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The yolk of an egg is a single cell, a very large one. Does the yolk have a nucleus/if it does, how large is the nucleus?
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The yolk is and isn't part of the cell. The actual "egg", the cell that gets fertilized, is the average size of a cell. While the yolk is within the cytoplasm of that call, when cell division begins, the entire egg doesn't develop, only the one cell. So the nucleus is going to be about normal size.
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Well it's not a "glorified" cell - it _is_ a cell. The yolk is not its nucleus though - it's where vital nutrients are stored. You can find the nucleus as a small spot on the yolk.
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Is it possible for liquid nitrogen to exist at room temperature?
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Going by the [phase diagram of Nitrogen](_URL_1_) that Wolfram Alpha pulls up, it is impossible for Nitrogen to be a liquid at room temperature, as its critical point is at a lower temperature. At room temperature, it can either be below the critical pressure (3.4MPa, or about 34 atmospheres) as a gas, or above that pressure as a [supercritical fluid](_URL_0_), a state which has features of both liquids and gases, but can't really be classed as either.
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The problem with nitrogen (and other gases like it, including oxygen, hydrogen, helium, etc.) is that no amount of pressure will cause nitrogen to liquefy at room temperature. Nitrogen has to be much colder than room temperature to stay liquid. If stored at room temperature, a sealed tank full of liquid nitrogen will explode because of the pressure that builds up. If you had a vessel that could handle the pressure build up then you would be left with a supercritical fluid when the LN2 heated up. Not a gas. But it would still eventually reach ambient temperature. So no, it doesn't simply stay cold. [Here is a phase diagram that might help.](_URL_0_)
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Why does Bile emulsify fat into micelles.
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The reason is precisely that of increased dispersion. Fats are horriblly immiscible with water, so they tend to form large particles, which would be hardly attacked by enzymes. Surfactants like bile acids are two-sided molecules that dissolve in fats with one end, and in water with the othe end, thereby allowing the formation of smaller "droplets" of fats (micelles) that can be easily digested.
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Cholesterol can be excreted through sweating and through the production of sex hormones (like estrogen), of which can be further oxidized and excreted in the urine. However, the major route of disposal of cholesterol is through the synthesis and excretion of bile acids and bile salts. Cholesterol is oxidized and modified extensively in the liver and conjugated to either glycine or taurine to form their respective bile salts. Bile is made up of these bile salts, and can be secreted into the bile canaliculus, which ultimately leads to the gall bladder, where it is stored. Bile is secreted into the digestive tract when food is eaten, as it helps in the digestion of dietary fats. The bile can either be reabsorbed and taken back up by the liver for recycling. If the bile is not reabsorbed, it is excreted in the feces. Therefore, the majority of cholesterol leaves the body through the colon, mostly in the form of bile.
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Why does my phone get significantly slower over time, even when using apps that ran fine less than a year ago?
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A big thing is that the apps you have now are not actually the same ones as you had a year ago. Update after update has come, code has been changed, features have been added. Each time this requires a little bit more storage and processing power. Compound this across 50+ apps and you have a phone that will run noticeably slower. Add on the fact that your phone is constantly storing data (cache, local files, ect.). Even when you uninstall an app, many of these files are still on the phone slowing it down.
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Mostly it has to do with how much software you have installed on your device. The more stuff you have running the more computing power each application takes. When you first open your phone it has very few things running in the background. But, after you install Facebook, Instagram, Twitter, WhatsApp, etc. those programs are all running in the background making your phone a little slower. If you want to get some of the speed back you can do a factory reset. This will make the phone much closer to the speed it was when new. But then it will slow down again as you reinstall apps.
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Is life possible in a universe of anti-matter?
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So far as we're aware, the chemistry of antimatter should be the same as the chemistry of matter. There are some differences in terms of weak interactions, but I doubt whether those would be sufficient to prevent life from existing.
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The main argument against such a scenario is that interstellar space (and intergalactic space) is not empty, but contains a small amount of gas. One would therefore observe a continuous stream of energetic matter-antimatter annihilations at the borders between the hypothetical matter and antimatter regions of space. No such signal has ever been observed. It would also be difficult to explain how matter and antimatter could be formed with such neat divisions in the early universe that would survive until the present day, rather than a much more uniform mix that annihilated itself very early on.
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Does the formation of condensation generate heat?
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Interesting question! The converse is certainly true - extra energy is released when condensation forms. This actually makes your air conditioner work harder if condensation is occurring - you can look up "latent heat of condensation." Here's what I'm not completely sure of - let's say you have condensation forming on the outside of a cup of lemonade. There is extra thermal energy released due to the condensation, but is that heat passed to the air or the cup? I would guessed that it is passed to the cup via a mechanism similar to evaporative cooling. The water vapor in contact with the cup passes its energy to the cooler molecules within the lemonade. Once it passes enough thermal energy to overcome the condensation barrier, it settles on the side of the cup as a liquid.
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The lapse rate. As warm moist air rises it will cool. In this case once the air parcel hits a certain height where the temperature is equal to the dew point the water vapor will condense. Where you have an expansive flat bottom cloud you have a somewhat flat layer where the dew point is somewhat all at the same height. A smaller cloud may be advected in or in the process of evaporating. In moister warmer areas you will see this Lower condensation level lower where as in a more arid environment it will be higher.
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What is happening with "Day One: Garry's Incident" in /r/gaming
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[This Video](_URL_0_) sums it up nicely, and is the #3 post on /r/games today. ~~Not sure how you missed that.~~ yay work censors! In short, developer provides game code to TotalBiscuit, who plays the game, criticizes it, and publishes video. Game developer files copyright takedown with youtube, claims its because the game was monetized with advertising, and says they are in the green. TB disagrees, notes that *all* his videos are monetized, *all* videos done on the game by other reviewers are monetized, and there are other critical videos that are monetized that were not taken down - so its clearly bullshit censorship. That's the skinny of it.
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They are not doing anything. Other gamers are calling the swat team on them to be a penis. For example this guy is suicidal or has a gun etc
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Is it possible to classically condition a function of the autonomic nervous system?
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Almost every example of classical conditioning involves the autonomic nervous system. A fear response is autonomic (sympathetic), Pavlov's original experiment was autonomic (salivation is parasympathetic), etc. Coming up with entirely non-autonomic examples is more difficult. One example may be a taste aversion response, for example when you feel nauseous just from smelling alcohol if you learn to associate alcohol with vomiting by repeatedly over-drinking. But the parasympathetic nervous system still plays a role in nausea and vomiting, so this isn't a fully non-autonomic conditioned response. Somatomotor conditioning is also usually associated with an autonomic response, for example a fear response (autonomic) may be conditioned together with putting your hands up in front of your face to protect you (somatomotor). [Here is a good article on the difference between somatomotor and autonomic conditioning.](_URL_0_) (I can access it through my university, not sure if you have access)
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Absolutely! It's not too terribly new of an idea... For example, norepinephrine, NPY, and ATP are all released from some sympathetic nerve terminals... [ref, 1995](_URL_0_) or GABA and glycine... [ref, 1999](_URL_1_) the list goes on... They don't generally have opposing effects as far as I know (that wouldn't make much sense would it?) More likely a cotransmitter is released as a modulatory factor for the primary neurotransmitter.
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Why do we get cold in a bath if the water gets slightly less warm, but not if we're swimming in a cold pool (after initial adjustment)?
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In a bath you are stationary. Your muscles aren’t moving, and aren’t warming up, whereas when you swim, muscles are engaged and warmed up. When the temperature drops, the added heat from moving makes the temperature adjustment less noticeable than say in a bath, where you are hardly moving.
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It is down to a "regional" difference in your body stick your hand in the water and your hand becomes 1 degree colder than the rest of your body, immerse your whole body in the shower and then your whole body is at the same temperature.
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Why is it that Coca Cola tastes so much better out of a glass bottle when compared to an aluminium can or plastic bottle?
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The glass bottles are ususally the Coke manufactured in a place where sugar is used as the primary sweetener, rather than corn syrup. (Usually Mexico if you are in the United States)
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Because soda is a carbonated beverage, meaning it contains dissolved CO2. CO2 dissolves in water at a low concentration (0.2–1.0%) and creates carbonic acid (H2CO3) according to the following reaction: H2O(l) + CO2(g) < = > H2CO3 Water is usually chilled and CO2 is subjected to high pressure to move the equilibrium forward. When you open a soda bottle you decrease the pressure and when you shake it you provide energy to the molecules to overcome the surface tension of the liquid both of which results in CO2 coming out the soda in the form of bubbles which is known as effervescence.
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Is a cat's field of view the same as ours, or is it more ovular as opposed to circular because of their pupils?
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In a lens system, apertures are placed close to the nodal point so they don't vignette. If you want to shape the visual field, the aperture must be moved further in front or behind of the point where all the rays cross. Humans and cats have their irises deep enough that they have little effect on the shape of the visual field.
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Cats like to have a good view of their surroundings, since their eyes are immediately drawn to any movement in their field of vision. This is how they are so good at spotting prey. They also have no trouble walking along ledges since they use their tails for balance. Cats walk along ledges because they like to, and because they can.
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Do we know who built the Kabba in Mecca?
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The Quran claims that Abraham/Ibrahim (yes, [that one](_URL_1_)) built the Kaaba with his son Ishmael. With respect to our Muslim redditors: it is more likely, of course, that building huts as places to store religious icons away from the sun was a common practice throughout Arabia and the Kabba was built by a tribe in the region (perhaps even ancestors of Muhammad's tribe, the Quraysh). The structure itself was rebuilt several times before and after the birth of Muhammad. Regardless, the current Kaaba was built in 1629 after a flood caused the original building to collapse by the architects of Sultan Murad IV. [SOURCE](_URL_0_)
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The Kaaba (the stone structure you're referring to) predates Islam. The Mosque it is part of used to be dedicated to numerous different gods in pre-Islamic Arabia. Mohammad then recognized it as also being a holy site of Islam. After Muslims were banished from Mecca and then returned and reconquered the city, they destroyed all the idols there and made Mecca and the Kaaba the center of Islamic worship (this is when Muslims began to turn to Mecca to pray). The meteorite that is the eastern cornerstone of the Kabba dates back to pre-Islamic times and supposedly fell on the site and people thought it marked the site as the gateway between heaven and Earth. Muhammad supposedly set it into the wall of the Kaaba when repairing it after floods struck the city.
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Why is it that singers lose their accent when they're singing?
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Techniques for proper singing (breath control, projection, comprehension for the listener, etc.) tend to counter accents. You'll still hear an accent on consonants (e.g. how do they pronounce R?) but since singing is mostly in the vowels, and there's ways to sing vowels that are better for one's voice and sound than other ways, a singer will usually go to that sort of "universal" singing accent.
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Curiously, are you american? Because 95% of modern music has adopted an american accent! So you might think it is neutral. Living in New Zealand its hard to make a choice to sing either in an American accent of English. American usually prevails. Try listening to Arctic Monkeys, Yorkshire accents from Northern England.
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Can you really "override" electronic combination keypads?
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You can override anything with a big enough sledgehammer. But on a more serious note, this is going to depend on the system. Some will be vulnerable to this, others will not. And I wouldn't be surprised if in some places at some point in the future if not already, they are required to respond to an override that is given to the police.
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I can't answer your question, but I use the / key dozens of times a day, every day. The choice had to be made at some point, and that was what "they" chose.
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How exactly does human regurgitation (vomiting) work?
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It's actually a very complex physiological reflex system. It can be initiated by the brain (hypothalamus) or by lower-level reflexes (gag reflex in the throat, for example). It's studied in detail. Vomiting is a chain-reaction of reflexes - in addition to emptying the stomach contents, you want to ensure that the airway is closed and protected, as inhaling vomit leads to massive lung damage (directly through acid-induced damage and inflammation, indirectly through infection) and kills tens of thousands (if not hundreds of thousands) of people each year.
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Your body takes a series of specific actions to prepare for vomiting and then to actually vomit: First your mouth fills with spit to protect your teeth from the acid & you take a deep breath (to keep from needing to inhale while vomit is in your throat and sucking it into your lungs). Then the muscles that move digesting material through your intestines reverse, pushing the contents of the upper intestinal tract back into your stomach. The pressure in your thoracic cavity lowers creating low pressure in your esophagus while your abdominal muscles contract , increasing abdominal pressure. Then the esophageal sphincter opens up and stomach contents shoot from the high pressure stomach to the low pressure esophagus and out your mouth like opening a bottle of pop. Repeat until stomach is empty.
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How do meteorologists determine how cold the weather feels, or what the "wind chill" is?
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They take into consideration a few variables, but two stand out. Wind speed and the actual temperature. There are tables readily found that can help you determine things for yourself. I think the theory behind the numbers in the table is based on the usual heat transfer equations. (Or in five year old terms, the more wind that hits you, the more heat it carries away from you, thus making it seem colder.) Source: _URL_0_ (this is in deg F) *Edit- /u/oceanjunkie beat me to the link, but I hope my short explanation helps you understand it all.
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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
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The Music Man is of course fictional, but was there a real moral panic about pool in the US in the early 20th c.? Also, was billiards seen as a wholesome game in contrast to pool? (third attempt)
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Follow up question: if there wasn't a moral panic related to pool or billiards, were there other similar panics in the early 20th c. US that the authors of the musical may have been inspired by?
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Pool tables were invented a while back in less enlightened times. There's a white entrance & a coloured entrance.
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How is public key encryption able to violate the laws of algebra?
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Generally public key cryptography relies on math problems that you *could* solve, but would require an inordinate amount of time. For example, factoring a number that is hundreds of digits long, that has only two factors, both also hundreds of digits long. That kind of thing takes years and years on great hardware.
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The math behind RSA encryption is pretty complicated, even to a college student. But it comes down to finding math that is easy to do in one direction, but hard to do in the other. Encryption is equivalent to the easy way, but breaking it is equivalent to the hard way. For example, squaring 5 is pretty easy, finding the square root of 20 is hard. I could make an encryption scheme based on that, but it wouldn't be all that strong. For a computer, multiplying two 100 digit numbers together to get a 200 digit number is really easy. Taking a 200 digit number and figuring out which two 100 digit numbers were multiplied together is really hard...like run for 100 years really hard. But *only* if they are prime. If they aren't, it gets a lot easier. And so does breaking the code.
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What exactly is net neutrality, and why are some people against it, and some people are for it?
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Net neutrality is a position that ISPs should not prioritize bandwidth for their chosen partners over competitors. It's all a big fight over TV. Cable TV is in the end a very expensive data stream. The internet is a very inexpensive data stream. As it became possible to deliver TV over the internet, entrepreneurs are looking to sell TV over the less expensive data stream (which would greatly reduce cable profits). So cable companies are attempting to control this source of competition via prioritization schemes (so TV competitors don't get fast, low latency connections). As Malcom Reynolds famously quipped, "'Bout 50% of the human race is middlemen, and they don't take kindly to being eliminated."
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The tl;dr in regards to net neutrality is that nothing is changing. We already have neutrality, but the big cable companies want to take it away. About internet being a utility, that means that it is something essential, like water and electricity, and that the government should be able to regulate it more closely.
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How can an LCD panel independently control every pixel without having one signal wire for every sub-pixel?
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Lets keep it simple and use a 3x3 grid of LCD cells. In front of the cells, there are 3 horizontal electrical conductors, behind the cells there are 3 vertical conductors. 1v 2v 3v [ ] [ ] [ ] 1h [ ] [ ] [ ] 2h [ ] [ ] [ ] 3h In order to actually change what a cell is displaying, you need to pass a current through it. For the top left cell, you'd send a signal on 1v & 1h. Middle cell? 2v & 2h, etc. Passing a current along *only* a horizontal conductor is not going to have any affect on that row without a signal on the vertical conductors as well. So in our example, we would need basically 6 wire connections to control 9 cells individually. As you scale it up, the disparity between number of connections and individual cells increasing exponentially. so for 640x480, you have 640+480 = 1,120 connections for 640 * 480 = 307,200 cells.
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ACTUAL ANSWER: most screens are subdivided into squares or columns of pixels. The actual pixels are made up of 3 subpixels. Yes, each subpixel has two wires going to it, usually one wire above going up and down and another line under the going sideways, like a grid with subpixels located at the intersections. Inside the screen there are "column driver" chips that take binary address along with color and intensity and convert it to a signal to drive the subpixels. If your monitor is say 1920x1080, you can have twenty 192x540 blocks each driven by their own driver. All these chips are then connected to the master chip that takes input from your videocard, does address conversion from x,y,intensity to column,x,y,intensity. This master chip has very few data lines coming from the videocard.
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Is it more energy efficient to leave my electric oven on?
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It's not clear to me that it would ever be worth it to leave it on. The warmer the oven, the more efficient will be the loss of heat out of the oven. So as the oven lowers in temperature, the rate at which the oven approaches thermal equilibrium with the outside air will decrease. I see no reason why the efficiency of the oven's heating mechanism (whether gas or electric) would improve when the oven is at a higher temperature. If anything it should be more efficient when the temperature is lower since there's a larger thermal gradient which enables the heating element to work more efficiently. The caveat here is that it will take some amount of time to reheat the oven. So my analysis is that the optimal strategy is to always turn off the oven immediately when you're not using it, but turn it on again at the right time so that it reaches the right temperature exactly when you need it.
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You are right, a gas oven is pretty much 100% efficient in terms of converting chemical energy to heat. Likewise, something as simple as a light bulb, or as complicated as a computer is also 100% effective in converting electrical energy to heat. That's the beauty of thermodynamics, eventually any external energy you add in to the system will be dissipated as heat. Usually this is a source of inefficiency, but not when your goal is to warm your house. So as long as your house is heated by conventional heating^1 (e.g. using a broiler or space heaters), then pretty much any device will be as efficient in turning external energy into heat as the central heating system. 1. I felt obligated to add this caveat since [heat pumps](_URL_0_) can have an efficiency, or a coefficient of performance greater than 1.
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Apart from succesfully being assasinated, did JFK accomplish much? Why is he so celebrated?
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He was incredibly charismatic, for one. He also started the Peace Corps. He started the US on the path to land a human being on the moon. He started a lot of what would lead to the civil rights act. He singed a (albeit partial) ban on nuclear testing. If he continued the rest of his term(s) in the same direction, he'd definitely had been remembered as a good president, and he had plenty of time to accomplish a lot *more* than he did so he *might* have been regarded *better* than he is now. And that's basically it, isn't it? That whole "What if?" That sense of lost potential. The tragedy of his assassination, and the shadow of it, lay over the American people as a whole for many years - and in many ways still do (there are *still* conspiracy theories about it). It was a moment that captured the minds and hearts of just about every single American, and many, many others around the world. That tends to elevate people to sainthood.
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JFK was elected in 1960. Recognizing the importance of the "space race," and the significance of scientific and technological development, immediately began a program of fostering education at all levels. Science and technology flourished, and US education became even more globally famous for excellence. Unfortunately, subsequent administrations failed to maintain the momentum that Kennedy started. Public assistance for education eroded, along with other infrastructure, at the same time as the media seized on the "crazy scientist" as the stereotypical model for smart people. Careers for scientists became less attractive due to diminished respect and compensation. The result was, and is, that young people seeking careers nowadays tend to focus on non-scientific and non-technical professions.
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Why the Spanish Empire did not start a kind of Commonwealth with it's former ex colonies, like the British Empire did, after they started to ask for Independence?
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Follow up question, did the downfall of the Spanish empire influence Britain's decision-making when forming the Commonwealth? Or was it the independence of the US that primarily influenced their choices?
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Spain did have an empire, and a fairly massive one at that. It had just about all of Central America, all of South America save Brazil, and also huge chunks of North America such a Florida, Texas, California, and at some point large parts of the Louisiana Territory. Like most colonial powers, Spain also had bits of Africa. Although I don't have sources for that and am certainly no kind of historian, I think this is pretty basic world history knowledge. So my question for OP is how do you see the British Empire having been different from the Spanish one, and what in particular about the Spanish Empire doesn't measure up to the British counterpart in your view?
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Why are ceramic materials such good thermal insulators in general?
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It may be useful to consider why metals are such good thermal conductors in thinking about the question. Heat can be transferred by atomic-scale vibrations, or in the case of metals, by electrons moving freely within the lattice. Since ceramics are made up of ions, the electronic contribution to thermal conductivity is practically zero. The only way for heat transfer within the ceramic is through the atomic-scale vibrations in the crystalline lattice (phonons). Wikipedia has a succinct write-up of the Wiedemann–Franz law, which describes thermal conduction in metals. tl;dr Metals have two ways of moving heat around: electrons and phonons (lattice vibrations). Ceramics only have the latter.
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Adding to the answer above, the observation that a good electronic conductor being a good thermal conductor is usually true and same vice-versa. In the case of metals, they have electrons that move very freely that help carry the thermal and electrical current. For insulators, the electrons are more localized to their atomic parent within the crystal. These electrons are not free to carry heat unless we drive the system at higher temperatures (but we also introduce more electron-lattice scattering as a result). So for insulators to transport this thermal energy, they mainly rely on the vibration of the lattice (i.e. phonons). Despite this, there is an excellent example in diamond, where it is a great electrical insulator but also a great thermal conductor.
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If ash from erupting volcanos cause rain, why is it that massive forest fires do not?
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My understanding of it is that it has to do with a large mix of variables. Those variables include how many particulates have been released into the air and remain airborne for water droplets to form on. (Volcanoes tend to release far far more particulates into the air). What is the relative humidity of the air that said particulates are in (normally really low in areas of wildfires). And do the particulates stay airborne long enough for single microdroplets on the particulates to come together and form clouds. Then do the clouds gather enough moisture to actually start raining. So the short answer to your question is, both can cause rain but it is less likely for wildfires to do so because the environment tends to not be conducive to providing the clouds enough moisture to rain.
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Lava flows/volcanic sources, spontaneous combustion from organic material overheating (think compost piles or certain types of coal), and rockfalls producing sparks are all potential other sources but lighting is by far the most common. Rainstorms are often isolated sporadic events. For example it can rain on one side of a stream and not the other and lighting doesn't have to strike under the rain, it can hit a tree on the other side of the stream so the rain will not effect any fire produced. There is also a lot of energy in lighting a good strike on a tree can set the whole tree ablaze even in a rainstorm. While the rain may put out the exposed fire, sheltered embers in the core of the tree can continue to smolder until well after the rain passes and then flare up. There are many areas where organic material is very deep and a fire may smolder underground. Fire can burn on the bottom of a log or under the shelter of a larger tree's limbs protected from direct rain.
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I'm trying to make a substance of 11.8 cP viscosity! Can anyone help me do this?
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Is there some reason it has to be exactly 11.8? Have you considered looking into viscosity standards if you need precision? Here's an example: _URL_2_ Does the viscosity need to be constant with respect to shear rate. i.e. is this a [Newtonian fluid](_URL_1_)? If it needs to be Newtonian, I'd stay away from slime, since the viscosity will vary with the rate of shear (sort of the rate of flow). If you want something newtonian I'd go with a mix of pure liquids until you get the viscosity you are looking for. Using [this table](_URL_0_) for liquids, I'd say you could mix ethylene glycol and water and end up around that value. You'd need to measure the viscosity of different mixtures until you got the right proportions. If you don't have the ability to check your mixtures, then you are going to be stuck using a known value, likea a pure compound or one of the standards I mentioned above.
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You're going to have to do a dimensional analysis to see why they can use viscosity with different units; where do their extra seconds come from?
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Have Muslim Countries ever experienced military weakness during Ramadan?
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I don't think so, because Muslims can be exempt from fasting for several reasons, and fighting a war is one of those. > Narrated Ubaidullah bin Abdullah bin Utba: Ibn Abbas said, Allah's Apostle fought the Ghazwa (i.e. battles of Al-Fath during Ramadan."Narrated Az-Zuhri: Ibn Al-Musaiyab (also) said the same. Ibn `Abbas added, "The Prophet fasted and when he reached Al-Kadid, a place where there is water between Kudaid and 'Usfan, he broke his fast and did not fast afterwards till the whole month had passed away. ([Bukhari, 5:573](_URL_0_))
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No. There was an attempt to do so in the first year of the war though. According to my book *The Iran-Iraq War* by Efraim Karsh, Iraq offered Iran a Ramadan ceasefire in 1981, but Iran rejected it. Karsh doesn't go into any details as to why the Iranians did so, and poking around the web hasn't turned up anything that explains why either, although [a site does make mention of an offer that was also rejected in 1987.](_URL_0_) The next year, no offer was made, and Iran actually launched a major offensive during Ramadan (giving it the name Operation Ramadan).
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Why we are the only thing that has to cook its food compared to the rest of the animal kingdom.
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We can eat raw meat, and animals need to deal with getting sick and dying from bad food. Cooking makes it safer and makes some nutrients easier to digest, but we can certainly eat meat raw.
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a) because we are social animals ourselves b) because we are not hungry If you go for some time without food a roof hare will taste awesome ;)
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In movies and television, "junkies" are often depicted living grouped together in buildings covered inside and out in graffiti. Where did this stereotype come from?
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Reality. Homeless junkies often DO congregate in abandoned/condemned buildings, which in inner city areas, often are covered in graffiti. There's not one on every block as Hollywood would have us believe, and there are plenty of unmarked drug houses... but the stereotype comes from the most visibly obvious example that happens in reality.
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Occupants have been a big part of recent German history. They often used graffiti to mark territories, political agendas or the like. This has spread to grafitti being very common now. A thing I noticed in Berlin especially was that a lot of the graffiti is really well made, because they are allowed to work at it in select spaces. Of course tagging and the like is as ugly as everywhere else, but the huge murals are more art than they are anything else
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What error does dyslexia cause?
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Dyslexia presents many issue, The big one is reading however there are others as well like learning in different ways(As such making normal schools largely ineffective), issues with memory, hard time with the maths, reading comprehension, and much more. The issue with reading and spelling comes from a hard time associated words(or rather their letters) with sounds, in return making reading and spelling complicated. We also use the "wrong" side of our brain while reading, the side that is used for less detailed work. As a result we get distracted easily(this side also is used for broad connections) because I can see the word blue and I will think of bob Ross because blue is a color like titanium white. Hopefully that answered your question, I'm not very good at using my words. Source: Have dyslexia If you really interested in a deeper answer there is a good book called the dyslexic advantage that really helped me out. Theres also a good ted talk on it that is a bit shorter. TED TALK: _URL_0_
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"Learning Disorder has been changed to Specific Learning Disorder" it's being absorbed by something else that is more descriptive. all dyslexia is not the same.
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Are there examples of how the Roman Legions of the 1st century, CE, communicated battle orders while engaged in battle?
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I have a question branching off this topic. In HBO's Rome, Lucius Vorenus is shown giving commands with a whistle, was this accurate and if so how widespread were whistles in the Roman army?
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I'm not really sure what you are asking. Are you asking if modern riot tactics can be traced back to the idea of a body of infantry moving as a tight group? Or are you asking if modern riot tactics are deliberately modeled after Roman formations, as in someone sat down and said "let's emulate Roman heavy infantry on purpose"? The vague and broad idea of infantry with shields fighting as a group is hardly revolutionary and clearly predates the Romans. I know a have a book at home dealing with modern law enforcement the and crowd control that focuses on major riots and civil disturbances over the last fifty years or so, I'll see if I can find anything there about the origins of specific tactics used by riot police and see if there's any clear indicator people tried to emulate the Romans.
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Why can we only synthesise 11 of the 20 essential amino acids?
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Actually, the term ["essential amino acids"](_URL_0_) refers to those amino acids that we can't synthesize.
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I am not sure who told you that amino acids can only be recycled, but it's not true. _URL_0_ Humans can only synthesize 12 of the 20 we require, maybe that's what you're thinking of?
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If a childs parent or parents are drug addicts or alcoholics does this effect the child in any biologically?
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Yes, during pregnancy. Alcohol and other drugs can cross over the placenta into the fetal blood supply and have various consequences to the fetus. Look up fetal alcohol syndrome. Also, sadly, with opioid addiction being so common today many babies are born addicts and have to be tapered down on morphine in the hospital.
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In some aspects, yes, but not always. Different drugs do different things to your brain. Weed activates certain receptors because it has the input for a specific type of receptor in your brain, but alcohol does not do this. Addiction itself is a genetic trait, but its not like when you were in middle school learning about genetics and did punnet squares; addiction is caused by a combination of different genes.
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Why is Google blocked in China?
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China is a one-party Communist state, that does not want its citizens to discover things contrary to government policy and positions. So an "open Google" where citizens can look up whatever they like was unacceptable to China. And a "censored Google" where the Chinese Communist Party could regulate what could be included and what couldn't, was unacceptable to Google. So it's blocked more or less by mutual agreement.
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Country specific ones follow the laws of that country. You can search for Tibet freedom on _URL_0_. but not _URL_1_ or Google.can Google was given a choice by Chinese gov. Either you make the search engine follow our rules, or you don't do business in China at all and China blocks _URL_2_ entirely
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Why do golf balls have dimples on them?
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The dimples trap small pockets of air around the golf ball, this reduces the friction and let's the ball fly farther.
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The dimples cause turbulence in the air as the ball flies. This turbulence causes the negative pressure behind the ball to be less severe, allowing it to fly further. Additionally the dimples will magnify the lift caused by the spin of the ball. If the ball is struck properly, it will have backspin and provide upward lift. If the ball is not hit properly, as in it's sliced, the spin will not be a perfect backspin and the slice will be magnified similarly by it's more sideward spin.
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Why are Australian video game prices always higher than America's prices?
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Australians are used to paying more, so companies charge more because they know we'll pay. Often referred to by companies by use of terms like 'localisation price adjustments'. Other 'reasons' (weak excuses that don't stack up) include transport, cost of business, taxes, exchange rate, etc. none of which explain the price disparity between Aussie prices and overseas equivalents.
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Aside from the mentioned sales tax you also have to factor in tighter consumer protection in Europe. But in the end it just "they charge more because they can". There are similar price inequalities for console video games between the UK and continental Europe. Games are cheaper in the UK, systems are more expensive. It's tradition that is hard to break.
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How was Hitler able to build such a massive and powerful army during the great depression? And why didn't France and England stop him?
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Britain would not have been capable of going to war in say, 1938, because it could not depend on the support of its colonies (Canada, Australia, NZ, etc.) The most militarily useful colonies were by this time all self-ruled, had all experienced the horrors of WWI, and didn't want to enter another European war. Only when it became clear how bent on domination of Europe Hitler was, and the reality of the threat to Britain, did this change.
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Most countrys had not fully recovered by 1939 and even Hitlers Germany with all its regained territory was just a shadow of the former Kaiserreich. WW2 would have propably happened even without the economic crisis. Germany had been in a financial crisis before and suffered of growing discontent,hyperinflation and crippling debts to the Entente before 1929. Another thing to remember is that facism had already been on the rise and was largely a product of the first Great War and revanchism. The crash in 29´ was certainly a catalysator to speed up the whole thing but it would have propably happend one way or another. There were enough other issue that could have sparked conflict or pushed the nationalsocialists or other extremist party´s into a position of power. And if that hadn´t happened then you would propably have seen another invasion attempt of the USSR to spread communism to central europe by force after the much needed reforms and industrialization attemps.
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Is there any evidence of medieval knights suffering from post traumatic stress disorder?
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It's a fairly common question around here. I don't know if knights are addressed specifically in these threads, but they're a place to start: _URL_3_ _URL_2_ _URL_1_ _URL_0_
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Hi there, not to discourage further comment on this topic (the origins of "chivalry" are interesting), but there have been quite a few threads about PTSD in the premodern world. These may be of interest for you as you wait for more comments: _URL_0_
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the physics behind non-Newtonian fluids
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ELIF answer: Think of sand. It's soft and flows when it's wet, but if you squish it down and wait for it to dry, it's hard and crumbly. Non-newtonian fluids are like sand that absorbs and dries out REALLY fast. So if you apply pressure, it gets harder like you squished out the water.
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I'm sure its flow behavior is non-newtonian, but in addition to that it's ... well, rubbery. I'd call it a viscoelastic material. These are materials that can both flow and bounce back.
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What exactly is management consulting?
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In short you're correct: a management consultancy does spend a lot of time investigating a company, then makes a number of recommendations to senior staff on how to improve their business. Not all management consultants are equal. The senior consultants and partners spend a lot of time with senior members of the company with which they're working, discussing performance and strategies. Mid-level consultants tend to hold interviews with mid-level managers to understand the company and recognise problems. They may also supervise a team of junior consultants. The junior consultants spend a lot of time typing up notes, fiddling with PowerPoint slides and ordering dinner because they're having to work very late. Depending on ability, performance and luck it takes about 5 years and an MBA to move from junior to senior.
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a consultant's job is to be the specialist. specialist of what? well it depends on the job. consultancy firms are basically full of specialists of every specialty. some are specialists in computer systems, others in accounting and finance, others in business analytics. companies hire consultants to deal with short term projects that they need a high skilled person without having to try to hire one blind from general job market.
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What happens when we breathe 'into our stomach' as opposed to breathing 'into our chest'?
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When you breathe normally without thinking, what happens is you contract muscles across the front of your chest (called intercostal muscles), causing your chest wall to move up and out. At the same time, you contract a muscle that separates your chest from your abdomen, called the diaphragm. Contraction causes downward movement of the diaphragm. Both of these muscle contractions make your lung volume bigger, and air passively flows into your lungs because of the pressure difference (from high to low pressure). Both your intercostal muscles and your diaphragm are consciously controlled, this is known as somatic innervation. *Breathing through your chest* is simply when you consciously put more of an emphasis on contracting your intercostal muscles. This causes your chest to move out more than usual. *Breathing through your stomach* is when your diaphragm moves downward towards your abdomen. Both achieve the objective of increasing lung volume. Source: Medical Student
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We still breath through our lungs. The concept of breathing through our stomach is a way to describe our organs in the gut being pushed away as our lungs fill with air. When you lift your shoulders to breath you don't get more space, you actually get less. The diaphragm flexes and the organs underneath need to move away, ergo our stomach getting bigger when we breath. as a vocalist, i am trained to breath through my stomach so that i may have better breath control. part of breathing through your stomach is a way to visualize taking a deep breath for support. Imagine when you breath a pyramid of air fills up, and of course the first part to fill up is the base, or the stomach. TL:DR Breathing pushes away our organs in our midsection. Breathing from the stomach helps us get more air in our body.
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Why does hair loss always begin from the top region of the head?
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I answered a very similar question a few days ago: _URL_0_ It has to do with varying levels of DHT sensitivity in different follicles of the scalp. Also, some men begin with the balding starting at the temples, which is how receding hairlines begin.
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Because your head hair does grow to a limit. It's just a longer limit than the hair elsewhere
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If we are rotating around sun in elliptical orbit and sun is at one of the focuses of ellipsis, then why don't we get period of very high temperatures and very low each year for both hemispheres?
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It's because the eccentricity of most planets is small. The Earth's is around 0.0167 today, but has changed drastically over the course of time (see [here](_URL_0_)). There is an effect, but it's extremely small because the Earth's atmosphere acts as a buffer. In addition, the much larger effect is that of the [axial tilt](_URL_1_) causing the major seasonal variations. It means that in the Northern Hemisphere, winter is when we are closest to the Sun, not farthest. Note that for other planets, such as Mars, this actually can have an effect. Mars' polar caps can change in size due to heating, and thus the climate as a whole (see [here](_URL_2_)).
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Earth's eccentricity, obliquity and precession means during winter we get less thermal energy from the Sun. Colder air means suspended water vapor condenses, and with less direct sunlight it less likely to evaporate and disperse.
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What would happen if we were to plant an organism known to survive harsh conditions on Earth on the surface of Mars, and tend to it?
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Unfortunately, Liquid water, needed for even the most extreme plants, is extremely rare to completely non-existent. Liquid water will not last long on the surface due to the almost complete lack of atmosphere. In addition, with such a limited atmosphere, plants would not be able to survive/function properly and would be killed easily by ultraviolet radiation. Our best hope would be to start with some sort of Extremophile microorganism. This link is a decent read on the potential for plant life. The data we have on the soil suggest it could support life however we would need to protect the plants by either growing them underground (therefore requiring artificial light) or indoors. _URL_0_
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> but would it stay there for so long that we would all freeze to death? Your bigger worry is starving because all the plants have died out due to lack of sunlight. But yes it would stay up there for months AT LEAST. Assuming you weren't caught in the blast or any of the earthquakes or megatsunamis such an impact would cause of course.
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Why is there still helium on Earth? Shouldn't it all have ended up in the upper atmosphere by now?
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Helium is produced by the alpha decay of heavy elements, and the Earth is full of lots of heavy elements. A lot of it becomes trapped in small pores underground, like oil does, and when oil is extracted helium comes out and is captured.
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Well, helium shortage partly stems from the supply side: it exists nowhere other than trapped underground, where it was formed by natural nuclear reactions. In the atmosphere, it's too light and leaves the planet. It's often near oil and gas but isn't always worth enough to collect. Helium is very useful as a coolant. Helium, when compressed greatly, becomes a liquid, and liquid helium is, what, 2K? That's -271C. Our lab used it for cooling the nuclear magnetic resonance machine. I imagine other industries and fields of research would need it too.
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Why can we see clearly underwater with goggles but not with our bare eyes?
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Your eyes are trained to deal with a surrounding medium with a low refractive index, like air. Water has a high refractive index, which makes the light bend in ways your eyes aren't expecting. Fish eyes are made for seeing while immersed in water, so they'd have the same problem in air that we do in water.
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True Night Vision Goggles take the existing ambient light and amplify it. That's why they can't be used like you see on TV and movies, because (and I know this from experience) just the light from a match several feet away becomes blinding. Cheaper, readily available to civilian "Night Vision Goggles" actually emit and infrared beam, that the human eye can't see but the goggles can, thereby illuminating everything in their field of view.
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What's the difference between a Broadway and an Off-Broadway live production? What makes a production a Broadway?
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Broadway theaters are the largest, seating 500+. Off Broadway seat 100-499. Off off Broadway seat less than 100. There are other criteria such as location and actor's salary.
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First off those type of shows are called Multi Camera Setups. And they play out more or less live like any other performance, they don't have to record one actor, then the other, then back and forth like single camera shows. Those are done on closed sets and are considered higher production value because there is more room for directing, multiple takes, and cinematography. They are really like plays and have an audience as a throwback to the days when it was done that way for lack of knowing how to do different. Television was live, variety and talk shows and the stage which is suited for this and might as well have an audience.
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How do blind people locate braille?
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There is a blind girl at my high school. For the first few weeks of school she has a person help her to class. Once she gets the feeling for her environment, she knows when she is near her classroom, and then gets close to the wall and feels around for the braille. I am guessing this is pretty similar to other situations with blind people. They know their environment and can feel around for the braille.
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Not all blind people are fully blind. Many of them have some residual eyesight. Enough, for example, to see very rough shapes or light vs dark. That can help them find the signs, after which it is just moving your hand over it until you feel it. If they are truly, completely blind, there is often trial and error. Many blind people are very good at memorising things, so if they are in the same place frequently, they know where to find the signs, and where about the text is. *edited to adjust some phrasing*
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Why is there so often a folder called _MACOSX in software downloads, even when there is a separate Mac download?
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This folder is automatically created by Mac's operating system. It's probably because the build server that creates the installation files, both for Windows, Mac and other operating systems, is a Mac.
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One gathers the files, one applies it. Depending on what it is, if you started installing before you had all the pieces of the file, and something happened to the download, bad things could potentially happen.
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Why are there no leopards in Europe?
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Both Leopards and Lions lived in Europe during the timeframe of early recorded history. Some lived all the way into the late Roman Era and possibly into the early Middle Ages. They were simply hunted into extinction by humans.
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Part of the explanation is that there have been hunted to extinction. There where Lions in Greece and the Balkans until 100AD, they where hunted and captured for gladiatorial games etc. Europe have had a large population for a long time so the floran and fauna are shaped by humans. There are few wolf and bears in Europe because in most places they are hunted to extinction. So if you compare with North America and Asia at the same latitude you will find some large cats that don't live Europe. But those areas are less populated and the population drops when large numbers of humans live there from habitat destruction and hunting. If I am not mistaken there are no large population of other animals dangerous for humans that live in the same climate. Venomous snakes, scorpion etc lives in warmer climate.
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What is the federal interest rate and how does it affect everyday people
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The interest rate on everything will likely follow a raise in the Fed's interest rate. That means your savings account will pay more interest, but it'll also cost more to borrow money to buy a car or start a business. A rise in the interest rate means that the Fed believes that the economy is growing too fast. Higher interest discourages investment and slows growth.
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To the average person, you might see your rates go up a slight bit, or banks might be less willing to create new loans. On a broad scale, the Federal Reserve loans money out to the big banks, who in turn loan it out to smaller banks, businesses, and people. By raising the interest rate, the Fed is making it more expensive to borrow money from them.
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Most mammals naturally can swim, why humans should learn it?
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Most mammals have their faces and noses aligned so they naturally protrude out of the water when they float. Their quadruped legs are aligned so their natural walking motion makes for a clumsy but reasonably efficient swimming stroke. Not so much with humans. Our normal floating position puts our faces underwater, and we have to uses our limbs differently than when we walk or run. This requires a degree of technique to do effectively.
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I’m thinking this is about why they need seawater to live in instead of freshwater, correct me if I’m wrong. They don’t have to live in salt water specifically (the seals my of Lake Baikal and the river dolphins do not). The ocean is much more productive in terms of food availability, particularly around the poles, so many more aquatic mammals can be supported by the ocean than by freshwater sources. To point, the very largest marine mammals like baleen whales and walruses all feed polar waters, even if they breed elsewhere. The ocean is where the food’s at. Credentials: I’m a mammalogy professor
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Why do we have headaches when we are dehydrated?
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A dehydration may occur after sweating when the body loses essential fluids to function properly. ... When the body is dehydrated, the brain can temporarily contract or shrink from fluid loss. This mechanism causes the brain to pull away from the skull, causing pain and resulting in a dehydration headache. Taken from medicalnewstoday.
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Your body is filled with veins and arteries, including your brain. These veins and arteries can get wider or thinner depending on what’s going on (cold/hot, too much/too little water). If you have WAY too little water, the veins and arteries shrink so much that your brain shrinks, and tugs on your skull. Source: google why dehydration headache, website medicalnewstoday
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Why those a tank of helium weigh less when its empty?
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Helium is less dense than other gasses at standard temperature and pressure. But the tanks have far more helium compressed into them than regular atmospheric pressure, so the gas inside is actually more dense (and heavier) than outside air.
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It is very, very big. So even if though the hydrogen and helium are very light elements, there are just so much of them. Just like a tonne of feathers and a tonne of bricks weigh the same. Edit: s/way/weigh. sigh. Thansk _Born_To_Be_Mild
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Why do we still have AM radio?
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AM radio has significantly better range so if you're a news organization you can make a new station ever 100 miles or way fewer AM stations and reach the same audience. Same goes for sports broadcasts.
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AM has poorer sound quality compared with FM, but is cheaper and can be transmitted over long distances. It has a lower bandwidth so it can have more stations available in any frequency range. FM is less prone to interference than AM. However, FM signals are impacted by physical barriers. FM has better sound quality due to higher bandwidth. Source: [AM vs. FM](_URL_0_) Generally speaking AM is for talk and sports because the quality doesn't matter as much as the broadcast area (or range) does.
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What is the observer effect? Does light really know when we are observing it and change behaviour depending on it?
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In physics, an "observer" is anything that interacts with a quantum object. For instance, when a photon hits your desk, the desk "observes" the photon. So the observer effect just has to do with whether anything is interacting with the photon.
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An "observer" is, loosely, anything which can make a "measurement". And in colloquial terms, a measurement is just an irreversible interaction with a classical measurement device. Of course this can't be a strict definition, because classical devices don't really exist; everything is subject to quantum mechanics. But in thought experiments, you can pretend like you have a measurement device which obeys the rules of classical mechanics, and you don't have to consider what it's actually made of. That device can be used to probe the properties of the quantum system in your thought experiment.
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Why there so much language diversity in Papua New Guinea and India, but not in China or France
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China actually has a lot of different languages (there is no single Chinese language). France used to have more linguistic diversity, but they made a concerted effort in the past to erase them like langue d'oc that used to be spoken commonly in southern France. Otherwise, geographical isolation tends to breed different languages, like in the Caucasus mountains (it has been said that there is one language for every valley) and Switzerland in the past. If people have little or no contact with other speakers of their language and a central linguistic authority is missing, languages tend to develop down their own path.
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Compared to where? Outside of the Western hemisphere, there is huge variety in native languages over relatively small areas. The only large regions I can think of that share a common language are the Middle East, North/Central China, and Russia and that's because they had massive empires instituting a common lingua franca.
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What process are coffee beans put through in order to be decaffeinated?
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I believe there are four ways, but the common way is through the use of CO2 and water at high pressure. The raw beans are put in a container with water and pressurized up around 1000 psi at this pressure the CO2 will extract the caffeine. The resulting liquid is removed and turned into pure caffeine for sale
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The method I'm aware of is that they basically wash the beans with liquid Co2, and make "Co2 coffee" with it until they have removed at least half the caffeine. I'm sure there are other methods, but this in particular wouldn't make it toxic or anything. Just weaker since it's been used already.
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Can we tell that dinosaurs were cold blooded based of bones and fossils or is that just the popular theory?
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One of the things scientists look at is rate of growth which they can see from patterns in the bone. Cold blooded animals have limited growth rates - essentially their metabolism isn't fast enough to sustain high growth rates. From patterns in dinosaur bones, it suggests many dinosaurs were warm blooded. However some exceptions to this rule in animals today are also cited. Tuna fish and sea turtles for example are technically "cold blooded" but have some capability of regulating and generating body heat. So, there is given some leeway to suggest dinosaurs might have also fallen in this inbetween category of being half and half between cold blooded and fully body temperature regulating warm blooded.
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There's no clear cut answer, but a theory I've heard is that ancient peoples found dinosaur skeletons and drew their own conclusions. I have no idea if this is true, but it seems reasonable.
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Could a plant grow from candle light?
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From my understanding Chlorophyll the primary chemical used to generate energy for a plant has essentially two peaks where light absorbtion is highest, in approximately blue/purple and red range of the visible spectrum. Anything can produce light based on the temperature. That is why the edge of a fire is red and the center is sometimes blue for a really hot fire. Most of a fire and a candles light is produced in closer to red and infrared. So my understanding is that it would be able to absorb the red light Given enough candles it could produce enough energy. My one uncertainty is if the blue/purple range is unnecessary for some reactions or simply another range that can be utilized. More than likely to have a plant grow effectively you would need to have enough candles to have a room light in the ballpark of the sun you see outside
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There can be, depending on the type of "light bulb". Plants are very good at absorbing light of certain frequencies that can make it through the atmosphere. Light bulbs that can duplicate this most closely do well for growing plants indoors, and there is little difference between the growth rates or health of plants. The main difference is when a light source that is very different than sunlight is used, as plant cannot get as much energy from it, or can be harmed by it. using the wrong type of light is a great way to wilt plants.
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