title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
|---|---|---|---|---|---|
[
"Male vs female perceptions of temperature? Why are women always cold?"
] | [
false
] | It seems to me that women experience cold differently than men. Is there any truth to this? If so, what causes the differences? | [
"http://www.timesonline.co.uk/tol/life_and_style/health/article5106854.ece",
"And women really do feel the cold more than men, but this is because they are better at conserving heat than men. Mark Newton, a scientist at W.L. Gore, the company that makes Gore-Tex, and a researcher at the University of Portsmouth, ... | [
"how about when you're in bed with a man?"
] | [
"This does not seem right. Average surface area of human is one point eight square meters. This would mean that blackbody human would have radiative power of over nine hundred watts and would need nineteen thousand kilocalories per day. That's roughly ten times the average human energy consumption. I suspect the re... |
[
"What material is the smoothest?"
] | [
false
] | [deleted] | [
"2) Polytetrafluoroethylene aka ",
"Teflon",
" ",
"1) ",
"diamond-like carbon"
] | [
"Are you referring to non-lubricated surfaces? For dry surfaces, the lowest friction coefficients are BAM (aluminum magnesium boride, .04) PTFE (Teflon, .05), and DLC (diamond-like carbon, .05).",
"If you consider lubrication, though, friction coefficients get much lower. BAM's CoF goes down to .02, and ",
"d... | [
"In the realm of biologic materials, articular cartilage exhibits a co-efficient of friction of 0.001. [1-3]",
"This is due to a variety of factors. I can go into detail if requested. Just wanted to add that biologic materials also have low coefficients of friction.",
"[1] Linn FC: Lubrication of animal joints... |
[
"How long did it take the last dinosaurs to die out after the Chicxulub impact event? Was it an immediate extinction event? Did it take months or even years?"
] | [
false
] | null | [
"It’s not really clear, obviously not all died out, as we see their ancestors of some theropods today (Birds!). Some suggest that the impact was enough to wipe out most beings pretty much immediately, while other theories suggest the earth would have suffered from rising sea levels, climate change ect which would h... | [
"The dinosaurs didn't just all drop dead after the impact. ",
"The extinction was quick on a geological timescale, but still took quite a while. It's still a matter of major debate how long. But it was more in the range of several centuries if not a few millennia than just months or years."
] | [
"The dinosaurs didn't just all drop dead after the impact.",
"Dinosaurs aren't extinct at all. There many, many dinosaurs alive today.",
"Natural History Museum: Why are birds the only surviving dinosaurs."
] |
[
"Face sweats after eating fruit."
] | [
false
] | Sometimes my friend says her face gets really hot and clammy when she eats fruit. It almost always happens with apples, but sometimes pears, pineapple, etc. do it too. Why might this be happening? Is it some kind of mild allergic reaction? She doesn't get any other symptoms like hives, pain, swelling that would go alo... | [
"My face does the same thing, my forehead feels like it is getting waxy or something when I eat apples."
] | [
"Does this only happen with fruit? For myself things such as Skittles and Starbursts also cause it to happen."
] | [
"I guess one of my first questions would be how often do you eat fruit, does it happen every time, and what does the rest of your diet look like? How often do you eat other things with a lot of sugar or that are high in simple carbohydrates?"
] |
[
"Do warm blooded and cold blooded animals have the same blood?"
] | [
false
] | As in, are the blood cells the same in both animals and just act differently or are they differently built all together? | [
"Different animals do have different kinds of blood, each species has variations in their blood cells. A particularly striking difference exists in animals with different pigments in their blood. Hemoglobin is what allows our blood cells to carry oxygen, and is also what makes blood bright red. But some other anima... | [
"Well, ",
"http://i.imgur.com/cjeW9o9.jpg",
" is a handy little picture to start you off, feel free to utilise Google U. if you want to know a bit more. But if you're asking how to get into it from an academic perspective, I'd probably recommend looking into molecular biology focusing on invertebrates or marine... | [
"This will certainly be a helpful infographic to start from, and I'm saving it to my screensaver rotation. Thank you!"
] |
[
"Would it be possible to see a Star fade away in daylight?"
] | [
false
] | null | [
"It could have been an ",
"iridium flare",
" from a satellite, which are very brief, though usually movement is noticeable. If it was already near dawn, though, maybe you only caught the very peak of the flair and didn't have enough of a time baseline to discern movement. Stars don't change brightness on that t... | [
"Is that possible to see in daylight?",
"I was thinking that, that the light source would be too big to dissapear in a few seconds, which is what made me ponder it.",
"It was about the brightness of an average star on a good clear night, but in the middle of a blue sky."
] | [
"The brightest ones could be. They can (briefly) reach magnitudes of -10, which is ~100x brighter than Venus. "
] |
[
"Is there a temperature that is too cold for a computer to run?"
] | [
false
] | I was just pondering this subject and I couldn't figure out if a computer would shut down, like when it overheats, but due to it being too cold. | [
"The chips will have a minimum temperature rating, typically either -25C (248K) or -40C (233K). (As an example, the Intel Atom E3805 is -40C). ",
"But there is an actual threshold below which SiGe (Silicon Germanium) transistors are not viable, which is between 40K and 100K depending on the exact transistor typ... | [
"What exactly is the physical mechanism that prevents operation at low temperatures? With bipolar transistors I'm thinking it's lack of thermal diffusion of charge carriers? What is the mechanism in MOSFETs?",
"EDIT: One reply below has been downvoted a lot, but no-one has explained what is wrong with it. Guys, y... | [
"Yes there is, and people trying to overclock on liquid nitrogen can hit this limit. It varies by individual processor. Silicon ceases to be semiconducting at -230C, and most processors (Intel 22nm at least) will boot at -140C. "
] |
[
"Can we predict when a gene will be expressed?"
] | [
false
] | Genetic modification in the 20th century was a bit of a crapshoot -- literally. You'd put a bunch of DNA on some pellets and shoot them into a plant with an air gun, it's honestly so hilariously basic, it's surprising that it works. That, and Sanford is just a crazy person now. But that's another story. But the genes g... | [
"We can predict whether or not a gene will be expressed based on its promoter and other regulatory regions that control its expression. But we don't need to predict expression as we can just measure RNA levels as ",
"u/jeanmi_bce",
" pointed out.",
"As for gene editing. It used to be more of a random process ... | [
"Well so you can measure RNA levels. Only genes being expressed will have their RNA present. So we usually run things like qPCR to test genetic expression. And yes modifying the genome (which is not expression) can alter expression of other genes by making them more or less accessible. Think of it like this, your D... | [
"Well, when you insert such a big construct such as an entire gene, you might as well introduce a strong promoter or any other regulatory sequence that we know will increase the expression of the adjacent sequence.\nYou pretty much got it right in your question. Insertions are somewhat random and we then select amo... |
[
"Are there any animals that have adapted to survive better in human made structures to the point where they wouldn't survive in the wild?"
] | [
false
] | null | [
"I would say that ",
"purple martins",
" qualify as a non-domesticated species almost entirely dependent on man-made structures. If not the whole species then certainly the eastern subspecies relies on nest boxes. ",
"Purple martins are large swallows that nest in cavities. They nest almost entirely in artifi... | [
"Pubic lice, and as TIL has told us many times, they're going extinct because less humans have pubic hair these days."
] | [
"I think chimney swifts are an even better example - they have only ever occasionally been found to nest in something other than chimneys or similar structures. Where they nested before people in North America built chimneys is probably large hollow trees that mostly dissappeared with the old growth forests of east... |
[
"Why doesn't Hubble's law imply an accelerating universe?"
] | [
false
] | I had been under the impression that Hubble's law described the accelerating expansion of the universe, but it looks like it predates the accelerating universe model by 70 years. Hubble's constant is in units of distance/time/distance. I would expect a non-accelerating expanding universe to have units of distance/time,... | [
"If the universe was expanding at a constant rate, I would expect to find every galaxy to be moving away from us at roughly the same speed, regardless of their distance.",
"No, Hubble predicts something twice as far away would be receding twice as fast. A linear increase. Actual measurements show far away things ... | [
"If a car is acceleration, you don't measure its speed in length/time",
". It's still length/time, it's just changing value.",
"Is the Hubble constant not a measure of acceleration? Does the constant change over time? If the universe was expanding at a constant rate, I would expect to find every galaxy to be m... | [
"If a car is acceleration, you don't measure its speed in length/time",
". It's still length/time, it's just changing value.",
"Is the Hubble constant not a measure of acceleration? Does the constant change over time? If the universe was expanding at a constant rate, I would expect to find every galaxy to be m... |
[
"Why do d and especially f orbitals show poor shielding effect?"
] | [
false
] | [deleted] | [
"You might say that the d and f orbitals are generally less ‘penetrating’ compared to the s and p orbitals; you are less likely to find an electron close to the nucleus for a d or f orbital.",
"Higher orbital angular momenta means that these orbitals have fewer radial nodes. So they typically end up with a large ... | [
"\"create space\"",
"It's not about the electrons having \"space\", it's about shielding the positive nuclear charge. This changes the potential the electrons find themselves in. Electrons that are more likely than other orbitals to be closer to the nucleus will shield the nuclear charge from other orbitals. The ... | [
"Thanks for the answer, that really helped me. I actually asked that to know why is mercury liquid in standard conditions and I found out its mainly because of the poor shielding effect of 5d and 4f. So does it mean that 5d and 4f orbitals have generally less places with high probability (radial nodes), so they can... |
[
"Is there an evolutionary counterpart to the mantis shrimp that lives on land?"
] | [
false
] | After reading the oatmeal comic about the mantis shrimp, I was wondering if there was a counter-creature to the mantis shrimp that lives on land, or even if it would be possible for the mantis shrimp to evolve to be a landed creature. Would it be possible to keep its incredible speed on land?(referring to its supercavi... | [
"You can't get cavitation in a gas. Gasses will always expand to fill the available space, so you can't get bubbles of less-dense gas in the same way bubbles can form in a liquid."
] | [
"I'd like to piggyback here to ask how much of a difference there is between supercavitation in a liquid and supercavitation in a gas. How much more difficult is it to achieve?",
"Also, could this be applicable in any way to aeronautics, in order to reduce drag?"
] | [
"you read my mind. I was thinking that the forces underwater would work better because its more dense or something like that."
] |
[
"Why does lighting a match do such a good job of obliterating bad toilet smells?"
] | [
false
] | Seriously. Sometimes I even gross myself out, but lighting a match seems to be a miracle cure. Is it that the scent is much stronger than the body odors, or does it somehow neutralize the chemicals that produce the smell? Just something I remembered to wonder this morning. | [
"You speak of a couple minutes, but a match only lasts a few seconds; the notion that that's enough to burn off the majority of the sulfurous compounds in the air seems very implausible. Besides, if that were the cause, the same effect should be obtained with any form of open flame, even ordinarily smell-less ones.... | [
"You speak of a couple minutes, but a match only lasts a few seconds; the notion that that's enough to burn off the majority of the sulfurous compounds in the air seems very implausible. Besides, if that were the cause, the same effect should be obtained with any form of open flame, even ordinarily smell-less ones.... | [
"I'm pretty sure that the smell of the sulphur igniting in the head of the match just overwhelms your sense of smell.",
"\nI know mythbusters did an episode on this, and I remember them disproving the \"burns up the smell\" idea. ",
"Here:",
" ",
"Hydrogen sulfide quickly deadens the sense of sme... |
[
"How and Why does the regularization of divergent series work when it comes to Casimir Effect/Physics?"
] | [
false
] | Hey. Background on what I know when it comes to this topic: I'm a math boy (if you up during real mathematician hours, smash that like) and at first, series/summation inspired me to learn more math, but lately I just want to learn/comprehend more math so I can apply it to summation (LOL) and in the past I've played wit... | [
"I've written about ζ-reg in the Casimir effect ",
"here",
", there are also a few links you could find more useful."
] | [
"One thing that often isn't appreciated is that the \"vacuum fluctuation\" derivation of the Casimir force is actually just a convenient approximation, appropriate in the limit that the fine-structure constant of the walls is infinite. The full derivation involves considering retarded (speed-of-light delayed) van d... | [
"The statement \"1+2+3+4+...=-1/12\" should be thought of as the following proposiiton: \"If 1+2+3+4+... could be assigned a number in a meaningful way, then this number has to be -1/12\". We'll let \"meaningful\" be vague, but the only thing that we require is that typical summation manipulations work. In fact, in... |
[
"Does the Coastline Paradox actually apply to reality?"
] | [
false
] | [deleted] | [
"You would in theory, but it doesn't matter. The coastline paradox didn't get its name because of what would hypothetically happen if you measured the coastline sandgrain by sandgrain, it got its name from what happens if you actually measure a coastline using the range of scales that people normally use to map th... | [
"The most real occurrence of this phenomenon is the border between Portugal and Spain.",
"Spain is much larger than Portugal and their size difference has actually led to them using differently fine grained measurements in their official cards. That lead to Portugal sharing a significantly larger border with Spai... | [
"You have to start fighting Quantum Mechanics around the atomic scale, which means you need to be careful about how you define the border/coast in the first place since everything is probabilistic. In principle if you come up with a definition based on the median border location, it will have a well defined length.... |
[
"Why do you initially start to feel better when you have radiation sickness?"
] | [
false
] | null | [
"Well I'll start it off by saying the initial \"sickness\" is actually your body's immune response. The body is literally trying to repair the damage caused by the radiation. The symptoms felt are how the immune system fights infection and damage. In fact most of the symptoms you feel when you get sick with the flu... | [
"This was answered nicely by ",
"/u/thetripp",
" in a ",
"post",
" from a while ago.",
"Acute radiation poisoning is the result of damage to very specific cell populations in the body. Radiation is much more lethal in cells that are undergoing cellular division. As a result, the stem cell populations that... | [
"No, radiation that kills off your bone marrow is targeted to a specific place in your body. This is just an example of a practical application of radiation poisoning.",
"In actual radiation poisoning, there are pockets of stem cells all over your body that get destroyed. It could be the ones in your bone marrow ... |
[
"Can oil spills happen naturally?"
] | [
false
] | I have always wondered this say there is a large oil reserve under the sea bed is it possible for the ground to break from movements in the earths crust or anything like that and for oil to leak out into the sea? | [
"Oil 'spills' would not be the best word for it. There are places on the southern coast of California and in the gulf of Mexico where oil seeps out of the ground, but its often unnoticed and occurs at a very slow rate. Also, this usually isn't pure crude oil, but a mixture of natural gas and other oils. A few speci... | [
"Look up La Brea tar pits.",
"These are called oil seeps and they can be seen around lots of oil fields in the world.",
"For example, the Denver-Juelberg basin in Colorado has oil seeps.",
"They are very low flow rate and trickle up through tiny fractures in the rock. Often, this oil has been moving up ground... | [
"A large number of mud volcanoes are present around the globe, both on land and under water. A large percentage of them are present in subduction zones. Many of them leak hydrocarbons. It is entirely possible that a natural oil spill happens due to an abrupt increase in activity of a mud volcano or due to a new rup... |
[
"Can Solar Panels be charged with Nuclear Radiation?"
] | [
false
] | Or is it possible to create equivalent panels which can? Sort of like "nuclear panels"? If so, can they exist now? Wouldn't it be more effecient utility of nuclear energy than boiling water? | [
"You can use the decay heat to produce electricity - ",
"radioisotope thermoelectric generators",
" (RTGs) do that.",
"For beta decays you can directly use the radiation and let the electrons fly through a potential difference - ",
"betavoltaics",
".",
"You could in principle let ionizing radiation pass... | [
"It just has to be higher energy. A gamma photon can produce multiple excitationts in a solar panel, and will still leave on the other side with most of its energy. It would probably give too much energy off on each interaction and result in significant additional kinetic/heat energy. Could make the charge carriers... | [
"Band gaps are of electronic nature so they should be in the eV range, just because atomic spectra is in this range."
] |
[
"How can the mass of a blackhole increase its impossible to observe something crossing the event horizon?"
] | [
false
] | [deleted] | [
"I assume by \" its impossible to observe something crossing the event horizon\" and \"we never see anything entering it\" that you're referring to the idea that it would take an infinite amount of time to observe matter falling to the event horizon.",
"This idea is a misleading simplification. If you naively cal... | [
"We can easily observe things falling into a black hole right up until the event horizon. When that happens, we can measure an increase in the gravitational force of the black hole exactly equal to an increase in mass of what just fell in. We still don't know what happens past the event horizon, but the gravitation... | [
"The mass of black hole is predicted using the effects it has on the space around it.For example,it is possible to calculate the mass by observing nearby stars or how the black hole curves the light we observe.\nAlso,sometimes stuff falling into the black hole heats up and starts emitting radiation,so sometimes we ... |
[
"What percentage of the ocean could we bring to a boil using all the nuclear fuel on earth?"
] | [
false
] | If we were to take all of the fissile material on earth (out of all the world's nuclear weapons and power plants and untapped mines), and created a giant nuclear boiler, what percentage of the oceans could we boil away? | [
"If you consider ALL uranium (not just that which can be profitably mined), you get some much more interesting numbers. ",
"http://en.wikipedia.org/wiki/Uranium#Biotic_and_abiotic",
"This estimates the total uranium content of the Earth's crust at 2x10",
" kg, giving 1.4x10",
" kg of U-235. ",
"One kilo... | [
"In a napkin sketch calculation, ll of the uranium readily available, is about 5.4 megatons of Uranium. Of that, 0.7% is fissile uranium, or about 37800 metric tons. That will produce roughly 3x10",
" gigajoules of energy. Boiling water requires 2540 kilojoules per liter.",
"Therefore, you're looking at ab... | [
"Aww, we are such puny humans! With all our grandiose dreams and ambitions!",
"What if we include non-fissile uranium, like the stuff that was in the cooling ponds at fukushima that boiled all their water away? I would guess there is a lot of lower grade radioactive materials that give off a lot of heat but aren'... |
[
"Would second-generation stars have had planets? Could they concievably have supported life as we know it?"
] | [
false
] | null | [
"...aren't we literally orbiting a second generation star?"
] | [
"To people saying our sun is a second generation star, our sun is actually thought to be a third generation star. Heavier elements weren't produced in the big bang. Population II stars although having low metallicity do have a significant amount. This means there must be a previous generation created with zero meta... | [
"No, they're named after the order in which they were discovered, which is the opposite to the order in which they developed, since we had to wait for better telescopes to discover the older ones.",
"Edit: Note that we can't actually see any Population III stars."
] |
[
"Thousands of species are said to have already gone extinct or are going extinct due to human activity. Are there any known species that are currently going extinct unrelated to human activity, and if so how is that measured?"
] | [
false
] | [deleted] | [
"Secondary question first. Avocados have unusually large seeds. Most mammals cannot carry or swallow a seed so large. The seeds were probably evolved to be spread by giant ground sloths.",
"Giant ground sloths (four tons of armored sloth!) were ",
"probably avocado eaters.",
" The sloths are gone but humans s... | [
"There is no 'should' or 'shouldn't' be when it comes to extinctions, but I assume you meant are there any species that would be extinct if it weren't due to human intervention. We would expect some species to have gone extinct over the past few centuries even if human didn't exist, based on what we know about the ... | [
"I dont think the Galapagos tortoise is a good example, after all the tortoise did spread to every island of the Galapagos. But they speciated (although thats still debateable) because there was little gene flow between the islands. So its not that the pinta tortoise only had one island, but that they evolved/speci... |
[
"Can the body create muscle mass from stored fat reserves or can it only create it from ingested protein?"
] | [
false
] | If someone's overweight and trains hard and gains muscle mass. Will the muscle mass gained be only from ingested protein via food or have the body been taking stored fat and converting it into muscle mass? | [
"While energy from mobilized fat can be used to synthesize fat, and the carbon and hydrogen may contribute to the final product, you can't make protein from fat alone.",
"Nitrogen is needed for protein (as well as traces of sulfur and other elements for some). There is no nitrogen in stored fat, nor is the body ... | [
"So, no. Basically, mammals have no way of synthesizing new amino acids. They can do various kinds of synthesis to make the carbon skeleton that forms an amino acid, but fundamentally animals have to make use of a transamination reaction to convert this carbon skeleton (an α-keto acid) into an amino acid. That is, ... | [
"Mindboggling as it might seem, but weight loss is mainly through two by products of metabolism, with most of it actually in gaseous form, CO2 and the rest water. I had never thought about it until my friend asked me about weight loss and I had to rethink about fat metabolism. \nthe \nBy increasing muscle mass will... |
[
"Can alloys be separated?"
] | [
false
] | Can alloy mixtures be split up, back into their elements? Like extracting the carbon from steel, to get pure iron, or separating the copper and tin in bronze? If it can, how does the process work? | [
"The process is different for each alloy. Some can be separated when heated by burning off impurities, others can be chemically bonded with elements that naturally disperse like an acid. You would need to google each process individually.",
"The only one I've ever tried first hand was using nitric acid to dissolv... | [
"Copper can and is purified using electrolisis, however in metals recycling, copper alloys are often recycled as their alloy, and perhaps some adjustments made during the melt to achieve a desired composition. ",
"Most wire in electronics is tin plated. Rather than purify it when it's recycled, it's melted into ... | [
"I though electrolysis only works in ionic compounds, not mixtures. Because the copper in the alloy isn't charged, it won't be attracted to the electrodes?"
] |
[
"Can a cell's proteasomes be turned against the cell?"
] | [
false
] | Since a cell's proteasomes identify and destroy what proteins need to be destroyed, could this be hijacked somehow to destroy the cell from the inside? | [
"Maybe, but it may not be the best way to do it. A distinct feature of the proteasome is that it has high specificity, meaning that only proteins that are tagged with ubiquitin are recognized and degraded by the proteasome. This specificity requires ATP. So, for destroying the cell, it may not be the most effec... | [
"I'm currently doing research on the proteasome and searched it on AskScience to see what came up. I found this and you just made my day to think of these things as laser-guided missiles."
] | [
"I thought my question was dead, but thank you for answering it."
] |
[
"Are there any mammals that do not sleep?"
] | [
false
] | null | [
"No. The brain needs rest, and that rest is taken in the form of sleep. Some aquatic mammals are able to use what is called Unihemispheric sleep, where only one half of their brain is asleep at a time - this way, they are still semi-conscious while their brain gets the rest it needs."
] | [
"Aside from the correct answers on unihemispheric sleep, the mammal that requires the least sleep overall is the giraffe."
] | [
"Every creature with a brain, needs to sleep. The question being, why do we need to sleep, why not just skip over it ?"
] |
[
"How did scientist know how much protection astronauts needed on first moonwalk?"
] | [
false
] | Seems like since there was NO basis for comparison they were kind of just "winging" it. Did they make earlier suits for animals and stuff to see which ones survived? I am just confused how they would know what would allow humans to survive in a place they had never been before? | [
"Seems like since there was NO basis for comparison they were kind of just \"winging\" it.",
"How so? We had already performed spacewalks. We know the design requirements which a vacuum poses.",
"Other than lower gravity and somewhat higher ambient radiation, there isn't much difference between a vacuum produ... | [
"I mean how did they even know it was a vacuum?",
"Because if space weren't a vacuum, anything orbiting the Earth at high velocities would burn up in short order. But meteors and such don't burn up until they hit Earth's atmosphere, and the probes we had sent up previously confirmed that there was very very littl... | [
"Here's two Wikipedia articles that should keep you busy for a few days:",
"http://en.wikipedia.org/wiki/History_of_spaceflight",
"and",
"http://en.wikipedia.org/wiki/Space_Race",
"The short version: Rockets were developed for military purposes (initially as weapons of terror, then eventually as a delivery ... |
[
"When I stand up/get up rapidly, and then I get extremely dizzy, almost to a point of passing out - What is that experience/moment called?"
] | [
false
] | null | [
"Could be ",
"Orthostatic hypotension",
". "
] | [
"Likely this!\nHave you had your blood pressure checked?",
"Do you drink enough fluids?",
"Are you on any medications?",
"It may be a good idea to wear a Holter monitor, which could measure and record your BP every hour or so (usually for 24 hours) and see if anything funny is going on. Ask your doctor."
] | [
"I agree! I think this is it, and I do have a semi-low blood pressure (I recently became a CNA so I had my vitals checked often during class), but I will check on that monitor with my doctor. Thank you!\nEdit: Grammar"
] |
[
"Askreddit didnt seem to interested in this question, trying it here. If it isn't correct place for if I apologize. How should the world mitigate the effects of climate change?"
] | [
false
] | null | [
"Just letting you know that your question was caught in the spam filter, and I'm going to leave it there. The reason is that ",
"/r/askscience",
" explicitly avoids questions looking for opinion or speculation, both of which would be required to answer your question. If you wanted to re-word and resubmit (sug... | [
"Thank You! I may do that later on or tomorrow. You have given me some things to think about. "
] | [
"No problem. If your post doesn't show up in /new within a few minutes, message the mods so one of us can free it from the spam filter. Have a good one."
] |
[
"How do solar panels turn light into energy?"
] | [
false
] | null | [
"Solar panels turn light into ",
" That's an important distinction.",
"The short answer is something called the ",
" Put simply, shining light on a particular type of material liberates electrons from the atoms in that material, causing them to move about. Moving electrons is electricity.",
"(Sorry, said \"... | [
"Being light. Light interacts with charged particles; electrons are charged. When an atom absorbs light, the outermost electron bound to that atom gains energy.",
"In some materials, electrons with certain energies are in what's called the ",
" Electrons in the conduction band — that is, electrons with the nece... | [
"shining light on a particular type of material liberates electrons from the atoms in that material",
"I guess that's the part I don't understand. What exactly is the light doing that would break the bonds?"
] |
[
"Are there any theories regarding why agriculture (or civilization) emerged independantly multiple times recently?"
] | [
false
] | As I understand things, the human species has existed in its modern state for more than 100k years, and for almost all of our history, we've been hunter-gatherers and then suddenly, like a cambrian explosion, settlement and farming emerged a few times almost at once. Is it simply that there hasn't been an epoch more co... | [
"David Christian of Big History suggests that it was a result of Earth coming out of the last ice age about 10.000 years ago. Humans for a large part appears to have had all the technologies necessary for agriculture, but simply didn't need to. Increasing in population put pressure on humans to increase the amount ... | [
"Prior to the last ice age is over ",
"100k years ago",
". We hadn't even left Africa at that point. It's too early in our history. "
] | [
"Very good question. Unfortunately, the answer is rather complicated. (",
": There were a lot of things happening at the same time. Agriculture is kind of like a symbiotic relationship between plants and humans, and the conditions that allowed this to develop first appear during the Holocene. How this relates to ... |
[
"Why are we unable to unite the theories of quantum mechanics and general relativity?"
] | [
false
] | null | [
"It is difficult from a variety of angles. The main fundamental difficulty is that in quantum mechanics particles' positions are defined with respect to some spacetime. In basic quantum mechanics this spacetime is flat, but you can imagine making quantum mechanics work in a curvy spacetime. That's not so hard. But ... | [
"It is theoretically possible that only one of the two theories needs to be modified in order to accommodate the other, yes. "
] | [
"It is possible but unlikely that we will ever have a correct theory. It would be difficult to know when you get there, since we will always have some maximum energy level or observational accuracy that is current state of the art, and we wont know what is beyond that until we get there."
] |
[
"Is anything truly random?"
] | [
false
] | Like it may SEEM to be unexplainable and random but is everything patterned if you trace it far enough? | [
"You are basically describing ",
"Laplace's Demon",
". However quantum physical processes can be completely random. e.g. ",
"radioactive decay",
" is perfectly random. You cannot predict when a particle will decay. You can only give probablities. "
] | [
"You cannot predict when a particle will decay. You can only give probablities.",
"We can't say that a process is certainly not deterministic just because the best description we have for experimental predictions of that process is stochastic."
] | [
"There are versions of quantum mechanics where it is deterministic behind the scenes, but in all cases there are events that cannot be predicted without ",
" with perfect knowledge and there's no way to get that knowledge. ",
"In other words, the existence of unpredictable events is a law of physics (and will p... |
[
"Do a baby's nails grow while it is in the womb? Or is that somehow inhibited?"
] | [
false
] | null | [
"Yes! and the rate of growth is much faster than adults; the nail beds first appear at 12 weeks gestation and by 20 weeks they can be seen as translucent layer-similar to fetus skin-, the formation of nails is pre-genetically determined and ends 34w for fingernails and 38w for toenails at that time they become har... | [
"Sorry, are you saying the nails ",
" growing after 34 (38) weeks and then ",
" growing after birth? What biochemical process triggers nail growth resumption? In particular, is it prompted by actual birth (e.g., the sharp switch over to breathing as method of oxygenation), or is it just timed to about 9 month... | [
"Yes, fetuses have nails that begin forming in the end of the first trimester. Fingernails develop earlier than toenails, but by the time a full term baby is born, they have complete nails. In fact, they often need a trim soon after being born! The stage of nail development can sometimes be used to determine how ... |
[
"How are food expiration dates determined?"
] | [
false
] | I asked this before, but without qualifying "food" and got a whole spectrum of answers. How are food expiration dates calculated? Do two items packaged on the same day received the same date? Why can two different products (companies), with effectively the same ingredients (e.g., salsa) have different dates? Would prod... | [
"Bacterial counts, color/texture degradation, aroma, and suchlike. Whether or not a product has 'gone bad' is either regulated (in the case of microorganism growth) or arbitrary (in the case of sensory quality). Arbitrary quality thresholds are usually determined by panels of human subjects, to determine when the '... | [
"This ",
"USDA page",
" has a wealth of information in this subject.",
"Of note:",
"\"There is no uniform or universally accepted system used for food dating in the United States\""
] | [
"Check on ",
" every few days? What is being measured? How does one determine \"things are going bad\" over time?"
] |
[
"Why do some words sound so similar in languages that have diverged so long ago?"
] | [
false
] | Examples (pronunciation) Mama: Chinese: mama Papa: Chinese: baba Two: Hindi: do French: deux Romani: duj Man: Tamil: manitan French: homme Romani: rrom Chinese: ren Ten: French: dix Hindi: das I found many other examples; mostly in numbers. Is it purely coincidental, or could it be remnants of homosapian's prehistoric ... | [
"Mama and papa are probably special cases, being reset each generation because they are some of the first things babies can say (repeated syllables help, a is apparently an easy vowel, the consonants only require control of the lips).",
"As for your other examples, all the languages you mention, except Chinese an... | [
"Wikipedia ",
"lists Romani as an indo-european language",
", though it is on another branch than any of the others you mentioned. I can't seem to find anything about an indo-european branch, the word indo-european seems to be only used about the whole group and proto-indo-european.",
"Anyway, I don't think i... | [
"Tamil: manitan",
"French: homme",
"Romani: rrom",
"Chinese: ren",
"I mean, I'm no linguist, but how similar are these words really? Maybe the pronunciations are closer but these don't look especially similar.",
"I'm only replying to you so as not to make a top level."
] |
[
"How does time dilation work?"
] | [
false
] | null | [
"Ah-ha! This is a fun one to answer. Time dilation occurs because of the principles of special relativity (there's also gravitational time dilation but the principle is similar to what I'll talk about here).",
"So what are the two principles of special relativity?\nthe first is that physics should work the same i... | [
"A clock in one inertial frame of reference will tick at a different rate than an identical clock in another inertial frame of reference, or another clock in a stronger or weaker gravitational field."
] | [
"Objects approaching a black hole get flattened because of ",
"tidal forces",
", not time dilation.",
"If there's anything incorrect in your post, you'll get downvoted. People can't upvote half your post and downvote the other half."
] |
[
"Do all bees belong to a \"nest\"? Are there any bees that live on their own?"
] | [
false
] | null | [
"Yes, there are some species of bees which don't form colonies, they are known as ",
"Solitary Bees",
"."
] | [
"And of bees that do form colonies, all bees have to live in a colony; to my knowledge, there is no species of bees that forms colonies where an individual bee may survive without a colony."
] | [
"Some bees are called solitary bees and do not live communally, but still build their own nests. ",
"Also, parasitic bees (aka cuckoo bees) do not search for food or build nests on their own. Instead, they use the nests and food of other bees. They can be classified into \"cleptoparasitic bees\" and \"social para... |
[
"How can we flip an electric cord plug over in a wall socket? Why don't the different charges fry the electronics?"
] | [
false
] | null | [
"This is by virtue of the outlet being wired for alternating current. In AC, the voltage cycles back and forth, and current flow does the same. The connection therefore has no polarity, though one pole is \"live\" side. Conversely, direct current has a high pole and a low pole, and current flows from high to low. I... | [
"In those electric devices where the cord can be flipped, the “direction” of the flow doesn’t matter. Like a lamp, where the electrons simply go in one end and out the other.",
"Where the “direction”does matter, there will be things to help make it work, such as the larger prong on the plug, or some AC-to-DC conv... | [
"In those electric devices where the cord can be flipped, the “direction” of the flow doesn’t matter. Like a lamp,",
"Lamps are one (two prong) thing that can't be flipped. In fact they were the main (possibly only) reason why the outlets have a wider slot. It's so the easy to touch screw base is not connected ... |
[
"What are gravitational waves and how do they affect objects?"
] | [
false
] | [deleted] | [
"First, you should feel comfortable going up to your professor and asking these questions!",
"Anyway, it's actually the gravitational potential energy of the system that is converted into gravitational waves. Because the orbit shrinks, the two objects will also orbit around each other more quickly, so the kinetic... | [
"No problem. And sorry, I was just checking, you are of course free to ask questions here. Tell him he should learn more!",
"Short answer: ",
"/u/Fenring",
" gave a very nice and concise answer to your follow-up, so I'll post a link there: ",
"link",
". ",
"Additional stuff: In the case of pulsar timing... | [
"No problem. And sorry, I was just checking, you are of course free to ask questions here. Tell him he should learn more!",
"Short answer: ",
"/u/Fenring",
" gave a very nice and concise answer to your follow-up, so I'll post a link there: ",
"link",
". ",
"Additional stuff: In the case of pulsar timing... |
[
"If you fill a tire to 30psi of normal air, and an identical tire to 30psi of another gas (say, helium) do they weigh the same?"
] | [
false
] | Would the helium compress more due to its lower mass, and end up weighing the same amount? | [
"No, assuming they are at the same temperature. In that case, each tire contains an equal number of molecules, but each gas has a different molecular weight. "
] | [
"No, the helium is still lighter. If you take the ideal gas equation and rearrange it, you get N/V=P/kT. On the left you have the number density, and you can multiply that times the atomic mass to get the mass density."
] | [
"An equal number of molecules? Fascinating. Thank you!"
] |
[
"Does hearing loss occur largely in a top down fashion? as in you lose the ability to hear high frequencies first?"
] | [
false
] | Could you lose hearing of low frequencies too? Low sounds don't seem to hurt my ears as much at higher volumes. | [
"High frequency loss is the most common but other patterns occur. ",
"I have low frequency loss; I can hear high frequencies just fine - considering my age - but I don't hear low frequencies well. ",
"I can hear most things just fine, but men who do not enunciate well are very challenging to understand."
] | [
"Hey, go get a hearing test. They don't cost much and results can be useful for life.",
"Low-frequency hearing loss will be correlated with difficulty hearing conversation in large groups of people, or difficulty hearing in locations with background music. Basically: do have trouble communicating in busy grocer... | [
"I took one maybe 7 years ago in college, but I'm wondering how often I should get checked. I make music for a living."
] |
[
"If we were to bring up a life form from the depth of the Challenger Deep..."
] | [
false
] | ... would it be able to survive? My understanding is that they evolved to live in those crushing depths, so does that mean that since there is a lot less pressure on the surface it would in a sense fall apart? | [
"There are several key effects at play:",
"Gas volume would change going from the deep to the surface so any internal gases, such as within an air bladder in a fish, would cause problems as they expanded at lower pressures.",
"Worse yet gas solubility in liquids, especially water, changes depending on pressure.... | [
"I believe death would result from your second point. It would likely be something along the lines of opening a soda bottle but happening inside of each cell. Raising them slowly so as to avoid the \"bends\" may be possible but then the animal would likely die from your 3rd point. "
] | [
"I think there are many organisms that migrate between tiers of the abyss and can withstand a relatively variable amount of decompression. Whether or not their cells could maintain structural integrity at 1atm would be really cool, but horribly traumatic to observe. Definitely feels like something from my nightmare... |
[
"How can a man survive after cutting off his own arm, while I almost faint from bloodloss after accidently cutting two fingers?"
] | [
false
] | null | [
"Human Body"
] | [
"Human Body"
] | [
"Thank you for your submission! Unfortunately, your submission has been removed for the following reason(s):",
"/r/AskScience",
"For more information regarding this and similar issues, please see our ",
"guidelines.",
"If you disagree with this decision, please send a ",
"message to the moderators."
] |
[
"What is the purpose behind Phillips(cross-head) screw heads? Mechanical efficiency?"
] | [
false
] | From an engineering standpoint, why does Phillips even exist? I can't count the number of Phillips I've stripped. I also find myself occasionally cheerfully wishing murder on the inventor. | [
"What?!?! Flathead is the absolute worst! Try using a power screwdriver on Flathead. Are you kidding me?"
] | [
"Created by Henry F. Phillips, the Phillips screw drive was purposely designed to cam out when the screw stalled, to prevent the fastener damaging the work or the head, instead damaging the driver. This was caused by the relative difficulty in building torque limiting into the early drivers.",
"http://en.wikipedi... | [
"Phillips exists as a self-centering screw head with a lock in mechanism. Think about it this way. The production line emerges as a new manufacturing technique. You need a screw head in which a bit can quickly insert itself, lock itself in, not slip out. The bit needs to be center into the head as well, so it r... |
[
"What is the smallest subatomic particle?"
] | [
false
] | That atoms are made of electrons, neutrons, and protons. I know that these are made of quarks, leptons, and gauge bosons. But how far does this all go? | [
"Electrons aren't ",
" of leptons, they ",
" leptons.",
"If by \"smallest\" you mean \"occupy the least space\", then the answer is \"your question doesn't ",
" make sense\". There are various ways in which we can define the \"size\" of a subatomic particle—de Broglie wavelength, impact parameter, et cetera... | [
"According to our current best knowledge, quarks and leptons have no substructure. Protons and neutrons are made of quarks; electrons are leptons. The gauge bosons - also apparently without substructure - mediate the forces that hold everything together."
] | [
"Protons and neutrons are made of quarks, which are fundamental particles. Quarks are bound to one another through the strong force, which is mediated by gluons, which are fundamental particles and a type of gauge boson. Electrons are a type of lepton, and are fundamental particles. They are bound to an atom's nucl... |
[
"Are there viruses that target viruses?"
] | [
false
] | Given that we have for example phages that specifically target bacteria is there something that is like a virus for virus? Not counting antiviral medication. | [
"Kinda but not quite. A virus needs to infect a cell in order to replicate. Another virus can't infect that virus on its own. However sputnik virophages infect cells that a 'helper virus' has already infected and takes over the cell. Kinda comes down to semantics in a way."
] | [
"A virus will always need a \"living\" host, for its reproduction (e.g. bacteria, plant, animal cells). Viruses are lacking the machinery that is required for the translation of their DNA/RNA and the assembly of their shells, as they are barely more than information in a container."
] | [
"It's interesting to note that ",
"giant viruses",
" tend to form large and complex viral factories inside their hosts, which are essentially specialized ",
"sub-cellular compartments",
", almost like a cell-within-a-cell, and that ",
"virophages",
" tend to infect these compartments directly and take t... |
[
"Why is fictional violence 'fun' but real violence terrifying?"
] | [
false
] | People spend hours watching youtube videos of crazy accidents,fights, or explosions, when someone gets injured we tend to laugh at it. However, when it happens for real and is actually experienced, it ends up being horrifying. I'm bringing this to askscience 'cause I presume it's something psychological. So, why do we ... | [
"People, either through observation or cognitive deduction, determine at an early age that fictional violence is incapable of causing tissue injury or end-organ damage."
] | [
"This may be related to Ramachandran's theory of laughter. We laugh when presented with something that might be harmful but wasn't, in order to alert those around us that the danger is actually safe. As with tickling, we are being attacked but not really.. Or when someone slips on a banana, it's only funny if his b... | [
"PhD in psychology here. I'm going to start out with the obvious. Fictional violence is not real and we know this, so we know there are no bad consequences, and no reason to be terrified. Just because the audiovisual stimuli bear some resemblance to reality doesn't mean we don't know the difference.",
"Now for... |
[
"Why were animals that lived in the ice age so much larger than the animals of today?"
] | [
false
] | I was watching a documentary, and it got me thinking: just why were the giant sloths, wolves, cats, bison, elk etc of the ice age so much larger than their modern counterparts? It it just more efficient for them to be smaller? | [
"This is controversial, but I think the evidence is good that the big ones were mostly killed off by humans. Big things tend to reproduce slower, slowly reproducing animals don't respond as well to hunting pressure."
] | [
"It's a question of the ratio of the envelope (skin) over the volume (internal body). When the ratio is small, you have fewer heat loss because the body is less exposed to the ambient cold air. For a sphere, the ratio goes like 1/r (= area r² / volume r³), so higher sphere radius decrease heat loss. In that way, la... | [
"So as one of the comments mentioned it has to do with surface to volume ratio. When you are a warm blooded animal you are constantly losing heat to your environment. Large animals have a smaller surface to volume ratio than smaller animals and so they are better able to retain their heat and thus they waste less e... |
[
"How long would it take before the stars in the sky move so much you'd no longer recognize them?"
] | [
false
] | I was watching BSG again and at some point in the show they start using constellations to navigate. And I was just wondering how long it would take until the stars move so far that you wouldn't recognize the constellations anymore, or just recognize the night sky in general. So lets say you went to sleep now, how far i... | [
"It would take a very long time. For reference, the star with the fastest proper motion in our skies (at this time) is Barnard's Star, a small, low-mass red dwarf about 6 light years away in the constellation Ophiuchus, the Snake-holder, just above Scorpio. Relative to us, it moves at about 107 km/s, and it's pro... | [
"Much longer than a normal human lifetime, at any rate.",
"Many of the bright stars in the sky have proper motions (its apparent angular motion across the sky) ranging from a few milliarcseconds per year (e.g. Rigel) to ~50 milliarcseconds per year (Polaris) to around an arcsecond per year (Sirius). For argument'... | [
"I started to come in and say \"not very long, only a few hundred thousand years!\"...I occasionally need to get re-acquainted with what normal people consider a \"long time.\" "
] |
[
"[Quantum Mechanics] What exactly is superposition? What is the mathematical basis? How does it work?"
] | [
false
] | I've been looking through the internet and I can't find a source that talks about superposition in the fullest. Let's say we had a Quantum Computer, which worked on qubits. A qubit can have 2 states, a 0 or a 1 when measured. However, before the qubit is measured, it is in a superposition of 0 and 1. Meaning, it's in c... | [
"Let's say we had a Quantum Computer",
"Oh god, let's not. Let's start a hell of a lot simpler than that, especially since quantum computers aren't even known to be ",
" possible.",
"Imagine any situation in which there are only two possible outcomes. Flipping a coin, say. The coin's either gonna come up head... | [
"Isn't the idea of superposition that they are in both states at once?",
"We all agree on the math, but we don't all agree on what the math means. You often see people simply stating their interpretation of the math as fact. However, there's a list of different understandings of what's actually going on. ",
"ht... | [
"It's mostly a philosophical question",
"Consider the instance it's about to pass through the slit(s). Mathematically we say it's a linear combination of it being at left slit and being at right slit. Let's say instead of letting it go through, we measure it. Now we only see it at one of the slits. What happened ... |
[
"Can scaring someone cause them to have a heart-attack?"
] | [
false
] | I've always wondered. It can be fun at times... giving people a little fright here and there. But is it harmful? Not specific to heart-attack... but to anything negative at all, really. | [
"Technically it can, but their heart has to already be in a very weakened state. The physiological response to fear includes a boost to our cardiovascular system. We need more blood pumped to more places so that we can respond quickly. The reaction can potentially be too much for the heart to handle and result i... | [
"We had a shooting here on Kauai this week and a witness had a heart attack. He was taken to Oahu and died a day later.",
"http://thegardenisland.com/news/local/kalaheo-shooter-identified-neighbor-dies/article_76d516e4-d55f-11e1-99a1-0019bb2963f4.html"
] | [
"Gotcha. Advice duly noted. Thanks!"
] |
[
"When standing on Earth, the moon is about as wide as your thumb held at arms length. But pictures of Earth from the moon appear the same size. Why? Shouldn't it be 3.68 times larger?"
] | [
false
] | null | [
"If you're on the moon and stick your thumb out then yes, it will look 3.68 times larger."
] | [
"Pictures can be enlarged, reduced or the camera could have zoomed in to create seemingly different proportions. I'd guess it's difficult to judge who big the Earth would be relative to your thumb from a photograph."
] | [
"Pictures taken of objects in the sky, whether the Moon from Earth or vice versa are subject to the focal length of the lens used to take the image.",
"Wider focal lengths will cause the objects to appear much smaller in the sky than they do to the naked eye, while longer, or telephoto lenses will cause the objec... |
[
"(Why) is it important, from an evolutionary standpoint, that I look completely unique? Of the billions of other people in the world, no-one else looks like me. Is this an evolutionary advantage, or just a coincidence?"
] | [
false
] | null | [
"Your appearance is determined in part by your genetics. So it's not about the advantage conferred by looking different, but, rather, the advantage of sexual reproduction (conferring different genes to progeny) vs. asexual. I recommend reading ",
"this",
" interesting page."
] | [
"But in the case of many animals, sheep or golden retrievers say, sexual reproduction results in offspring that look almost identical to their parents and siblings. \nEven with genetics is it not possible for me to look almost identical to my father or mother. If so, then what evolutionary advantage is their to me ... | [
"Seemingly almost identical to us because we do not focus on the minute differences. But some farmers can distinguish between their sheep by sight alone. Or a pet owner can distinguish between their dog and someone else's. "
] |
[
"Does the expansion of spacetime allow for a decrease in entropy?"
] | [
false
] | It seems to me that an expansion of spacetime allows for an increase of potential energy through the gravitational/electroweak/strong forces without any energy being added to the system thus decreasing entropy. I believe an expansion of volume also decreases entropy because of the addition of possible arrangements corr... | [
"Only gravity (and the dark energy, whatever that is) has significant effects on cosmological distance scales, so EM/strong forces are not an important consideration in the expansion. ",
"Also, this is incorrect:",
"an expansion of volume also decreases entropy because of the addition of possible arrangements"... | [
"Ok that last line really interests me. If not a heat death do you just mean a citation where temperature extremes are total isolated from each others?"
] | [
"There are two lines of argument:",
"ekpyrotic (colliding branes) cosmology"
] |
[
"Would be possible to copy the regeneration properties of a fingernail and use them else where?"
] | [
false
] | null | [
"Not restricted to humans? Hold on i'll check with my hamster!"
] | [
";)"
] | [
"Yeah. I saw the error of my ways. Changed it."
] |
[
"To what extent does the conversion from metal wires to fiber optics mitigate the economic risk from solar storms?"
] | [
false
] | My question occurs while reading about the worst solar storm ever recorded, in which telegraph lines generated electrical fires. It seems that perhaps the greatest terrestrial risk from solar storms are very long metal circuits, such as might exist in power or communications lines. However, power cables are, by defi... | [
"The long haul optical fibers have conductors in them to power the optical amplifiers needed to boost the signal periodically. If the power surge that is induced in the line damages the amplifier systems, game over. Short runs can be just the optical components as the losses are low, and those would be stable in an... | [
"There are power lines that run along to fiber to power the boosters that are spread along the way. 30km gaps between boosters is normal for undersea fiber for example. Gotta get power to the ones in the middle."
] | [
"There are both conductive and nonconductive types of optical fiber ",
". See ",
"here",
" for some basic information around this.",
"While it's possible for conductive components to transmit current, I'm unclear as to their possible effects on the fiber. Current guidelines (e.g. in the US - Article 770 of ... |
[
"What controls the timing of birth in humans? Do conditions in the womb become toxic, driving the birth process?"
] | [
false
] | [deleted] | [
"I don't know if you find my answer satisfying, but here goes (also sorry for my English). \nAs you (hopefully) know, the mother provides nutrients (glucose, among others) to the baby. At some point, the mother can't provide these nutrients to both herself, and the baby, because the baby is getting too large. This ... | [
"This may not be a perfect answer, but perhaps it's a start: It is the complete development of the fetus' lungs that is the catalyst in beginning the birthing process. Lungs have a liquid coating called \"surfactant\" to keep themselves from collapsing from their inability to keep air in. This chemical is crucial, ... | [
"Very nice; thanks."
] |
[
"Chemically speaking, is wood similar to the human body?"
] | [
false
] | [deleted] | [
"Water, carbon and protein are three very different things. Water is a molecule that is present in all known life. It is an excellent universal solvent. Carbon is only present in living material as part of bigger molecules; as far as I know never in it's pure form.\nProteins are a huge class of widely different, co... | [
"I checked the definition, and you're right. However, substituted hydrocarbons are also counted as organic compounds, so the rest of my answer still holds. Thanks for the rectification."
] | [
"All living things consist for a huge part out of water and hydrocarbons. Hydrocarbons are molecules which consist out of a backbone of carbon atoms, with hydrogen atoms, or sometimes other elements such as nitrogen or oxygen, attached to it. These molecules can range from very simple (such as gasoline) to highly c... |
[
"How does adding chemicals to gold make it purer in the refining process?"
] | [
false
] | I understand that when gold is made into jewelry, it is made into alloys with other metals to make it more durable and cost effective, but I don’t understand how the added chemicals during the smelting process make the gold more pure. Wouldn’t adding stuff to it make it less pure, rather than the opposite? | [
"Let's say you have a mixture of gold and some element, Q. Q likes to be alloyed with gold, but it likes to bind with X even better. So, when you melt the gold, you sprinkle in a little X into the liquid. The X binds with the Q, turning it solid (we've chosen X carefully so this happens), and it either floats to th... | [
"Yep, same sort of idea. You'll find the same technique with people casting iron/steel and aluminum, too."
] | [
"Ok. So that’s like making cheese, and you’re skimming the excess off the top before continuing, right? I’ve seen videos, and all I’ve seen is the extra stuff being added before it all goes into the crucible. Then it all gets brought to a molten state. I never see the removal of the impurities, just the forming o... |
[
"If the Moon orbits Earth and Earth orbits the Sun, what does the Sun orbit?"
] | [
false
] | null | [
"The Sun orbits the galaxy. So it doesn't exactly orbit one thing, but rather the combined mass of the other stuff in the galaxy makes it follow a path that takes around 250 million years to complete one orbit.",
"The Sun's temperature is determined by its own heat production, since any other stars are many light... | [
"The Sun orbits the galactic center along with pretty much everything else in the galaxy. In turn the Milky Way is gravitationally bound (not to be confused with orbit however) to other large structures in the Local Group. In turn these are gravitationally bound to enormous structures formed from groups of galaxies... | [
"sun orbits the center of the Milky Way galaxy called Sagittarius A*",
"Not quite. While we orbit the region where Sag A* happens to be, the black hole itself has almost no significant gravitational influence on the Sun because of the distance. It's more accurate to say the Sun orbits the center of mass for the e... |
[
"Is all oil and natural gas from dead organisms?"
] | [
false
] | [deleted] | [
"For the title question, yes, on Earth naturally occurring oil and natural gas is derived from organisms, mostly marine microorganisms. There are countless resources online that describe the formation of petroleum in detail, e.g. the one ",
"wikipedia",
" isn't a bad place to start.",
"With regards to the Tit... | [
"Fuel is burned in periodic little explosions inside cylinders which move pistons down. That motion is converted into rotary motion and that turns the wheels."
] | [
"Petroleum is refined into gasoline, which in the right conditions is explosively combustive. Those explosions are used to propel pistons. The pistons are connected to a crankshaft which converts that energy into circular motion, which ultimately turns the vehicle's wheels.",
"Petroleum can also be refined into d... |
[
"Is there such a thing as a \"fourth generation quarks or leptons?\""
] | [
false
] | Are they possible to make and just have extremely short lifespans or is the third generation of top quarks, bottom quarks, taus and tau neutrinos has heavy as quarks and leptons can possibly get? | [
"A simple, fourth generation of fermions with the same couplings as the first three generations is ruled out by the Higgs boson coupling measurements: ",
"https://arxiv.org/abs/1204.1252",
"There are ideas that there could be a fourth \"vector-like\" generation of fermions. These would then have equal couplings... | [
"There is no experimental evidence for them but nothing in the standard model prevents there from being more than three generations.",
"It is, perhaps, interesting to point out that three generations of quarks might be required for life to exist! The CKM matrix which describes the way in which mass and weak eigen... | [
"Could you (or anyone else reading this) expand on the way this potential \"vector-like\" generation of fermions would couple differently to the Higgs, relative to how the presently existing generations couple? "
] |
[
"Do pheromone colognes like Pherlure or PherX actually contain pheromones and do those colognes actually work?"
] | [
false
] | [deleted] | [
"Chemist here. If it attracts poontang or just makes you more confident so you pick up more 'tang, I say it has served its purpose. ",
"The scientist in me, however, is tempted to call bullshit. Show me proof.",
"PS: I've always wanted to incorporate the word \"poontang\" into a scientific discussion."
] | [
"As our smelling abilities are not as acute as most animals, we cannot smell pheromones per se. But there's some reaction to the pheromone molecules, at the olfactive cell level, that is known to trigger some hormonal responses. So, the best those products could achieve would be some sort of unconscious response th... | [
"So far, all the tests have been inconclusive. I remember reading multiple studies and the results varied massively, inferring theirs no correlation between the pheromones and the \"Picking up\".",
"Also: I'm sure a biologist and chemist will come by soon to expand more on why it shouldn't work (pheromones in col... |
[
"Is it possible to un-polarize polarized light?"
] | [
false
] | And if so, what applications might this have? | [
"You're doing the maths right, but interpreting them wrong. To understand how the polarization of light really works you have to dive into the quantum mechanics of the spin state of an individual photon. When you do that, you'll find that in fact no, it is not possible to ",
" the spin state of a photon. Which ma... | [
"In optical measurement instruments, a \"diffuser\" is sometimes inserted into the light path; think a rough piece of aluminum or some such. This has the explicit goal to get rid of the polarization in the incoming light (to be more exact: to have all possible polarizations represented equally).",
"This is done b... | [
"This is wrong. Polarizers do change the light.",
"For instance, lets start with unpolarized light and pass it through a polarizer so that it comes out linearly polarized in the x direction. Then we can pass it through a linear polarizer with a transmission access at 45 degrees. Now our light is polarized at 45 d... |
[
"Is the assignment, positive and negative, to the charges completely arbitrary? Or is there an actual mathematical significance for doing so."
] | [
false
] | null | [
"Completely arbitrary."
] | [
"Ben Franklin coined positive, negative, charge, and battery with relation to electricity.",
"He discovered that there were two types of charges, positive and negative. He did not know whether negative or positive charges were transferred, so he guessed - positive. He was wrong, but only by chance (and if he wa... | [
"It's arbitrary what's negative/positive, but the fact there are two types of opposing charges that repel/attract the way they do is not."
] |
[
"How does altitude of detonation of a nuclear bomb affect the “fallout area?”"
] | [
false
] | When a nuclear bomb is detonated, the surrounding air is almost instantly heated and rises rapidly. Various debris, gasses, and radioactive material are brought up with this air, and a repeated heating and cooling process occurs that forms the infamous mushroom cloud. The cloud, however, will reach a maximum height whe... | [
"In general, the main concern regarding fallout and detonation height is how much dirt and debris is sucked up in to the radioactive fireball. This will determine how much, and when, the radioactive material in the cloud \"falls out\" to the ground. ",
"If you detonate a bomb sufficiently high (a multiple of the ... | [
"This is an awesome explanation. Thank you!"
] | [
"No problem. ",
"NUKEMAP",
", as an aside, takes altitude into account when it calculates fallout. So you can play with it, if you want. It uses a scaling rule, derived from government publications, that reduces the intensity of the bomb as a factor of height of burst in between the two extremes of HOB = 0 and ... |
[
"Do shirts shrink due to being washed in hot water or due to being dried in a hot air dryer? Why?"
] | [
false
] | Title is all that is necessary. | [
"Textile Engineer here (yes, there is such a thing):",
"\nMost the clothes that shrinks is cotton. The reason cotton shrinks (normally in the dryer, but some in the washer) is because the heat of the dryer adds energy to the polymer chains. This will return the amorphous regions of the polymer chains to their n... | [
"This will return the amorphous regions of the polymer chains to their natural, unaligned state.",
"This is worded a little confusingly. Do you mean the induced crystalline regions will return to their natural amorphous state when heated?",
"...so when heat is applied, the amorphous regions somewhat align. The ... | [
"My understanding of the process is somewhat similar to dirtay's, except I view it from a polymer scientist's point of view so I have different language.",
"Its not that the cellulose chains crystallize. But there is (and I hesitate to use this terminology because its ",
" scientifically but is able to provide ... |
[
"How can neutrinos change flavor?"
] | [
false
] | How can neutrinos change flavor? Doesn't that mean they must be changing mass? Where does the extra mass come from? | [
"How can neutrinos change flavor? Doesn't that mean they must be changing mass? Where does the extra mass come from?",
"The neutrino flavors don't have definite masses, and the neutrino masses aren't attributed to definite flavors.",
"Mass and flavor are incompatible observables for neutrinos, just like positio... | [
"I was under the impression that a neutrino is made of types of waves. The phase of the waves determines the flavor of neutrino. Is that inaccurate?"
] | [
"It might be accurate in some particular sense but is misleading, and I've never heard that description before.",
"I think what's meant by \"being made of waves\" here is the following:",
"Suppose I have an apparatus to measure the flavor of a neutrino in some particular mass eigenstate. The chance of measuring... |
[
"Why are there so few neurons in the Cerebral Corex, compared to the number in the Cerebellum?"
] | [
false
] | I have searched for answers online but haven't found anything satisfactory. From what I know, there are ~69 billion neurons in the Cerebellum, and ~16 billion in the Cerebral Cortex. This seems strange, considering the fact that the Cerebrum accounts for roughly 85% of brain mass. . Is 16 billion a rather low number in... | [
"Just a med student here. Id like to point out, that the number of neurons doesnt equal the number of synapses (connections). Those are responsible for the amount of information the brain holds. Neuron bodies are just something that connects them together and produce building blocks for them. So to my understanding... | [
"I don't think we yet understand how exactly the cerebellum processes information but you have to consider how vast amount of stuff it has to do. It controls the movement of your body, it learns the movement patterns and how to reproduce and adapt them in different situations. When you learn to walk, it is actually... | [
"Ah, I didn't realise they could vary in size, that's interesting. Thanks for the information.",
"I've become quite interested in this topic recently but I know it's like spitting into the ocean when it comes to such a huge and complex topic like neuroscience."
] |
[
"Where can I learn about the genetic differences and similarity between fruit?"
] | [
false
] | How much has the genetic sequencing of all the different types of fruit helped to understand their relationships? Where can I learn about it and find out things for myself? Although I wouldn't know what to do with it I also wonder if all the DNA data is online? | [
"This won't exactly give you the spelled-out relationship of two fruits, but nonetheless: Check out ",
"TimeTree",
". It takes any two organisms and estimates how long ago their phylogenetic lineage split - i.e. when they had their last common ancestor.",
"For example:",
"Strawberries and Durian evolved in ... | [
"One of the most interesting courses I ever took was on economic botany. We discussed the relationships between many of the fruits and vegetables that we normally eat. ",
"Did you know, for example, that broccoli, cauliflower, brussels sprouts, cabbage, kale, collard greens, and kohlrabi are all the same species?... | [
"Timetree is pretty cool, there's also this resource for phylogenetic trees: ",
"http://tolweb.org/tree/",
"Hillis is a pretty amazing researcher, and he helped write the book on molecular systematics (",
"literally",
")."
] |
[
"What types of particles can I detect using a homemade cloud chamber?"
] | [
false
] | This video claims you can see subatomic particles at home. Does that method really work? And what kinds of particles can I see? Thank you! | [
"Yup those are real! ",
"They're very simple cloud chambers.",
"As a rule of thumb most incident rays are protons, however, you don't see these on the ground, they generally interact with the atmosphere ",
"producing a whole zoo of particles.",
" ",
"An indiscriminate detector will see mostly electron, m... | [
"Your local supermarket might have some. Publix usually has it, but if you're not in the south I don't have a good answer."
] | [
"Where does one get dry ice? I used to live in Japan and you could get it anywhere there. Where does one get it in the U.S.? "
] |
[
"Determining the Product of Exponentials Formulation for the kinematics of a robot"
] | [
false
] | I'm just starting out in robotics and am doing some self study... I'm trying to figure out how the Product of Exponentials Formulation works when describing the kinematics of a robot. [1] Here's a link to a free text book by Murray that describes it... mostly. Ok, sort of. Chapter 3, around page 80 or so, begins to des... | [
"I'm not sure if this should be tagged as Engineering or Mathematics... so, please let me know.\nThanks."
] | [
"I suspect that ",
"this",
" is the book to which you're referring. At the very least, it has matrix exponentials on page 89. If so, I'd first like to point out that those are xis, not epsilons.",
"Now, if that is the book about which you're talking, I'm not sure where your confusion comes from. The basic def... | [
"Yes. That's helpful. Thank you. I'm trying to use the Euler Angles on page 31. I think I understand how to set up the first three columns of the rotation matrices.",
"\nMy next question is about the fourth column, the translational components. I'm having some trouble seeing how to \"add\" the components from suc... |
[
"So how do you evolve from 44 chromosomes from 42 chromosomes?"
] | [
false
] | I understand, from listening to one of Ken Miller's talks, that our 2nd chromosome is actually the result of the fusion of two chromosomes, found in related species. But how could such a thing spread. I can envision such a fusion taking place, and producing a viable offspring. But how does such a mutant find a compatib... | [
"But how does such a mutant find a compatible mate?",
"Chromosome number doesn't really matter much when finding a mate. Your ",
" have to line up, and while having the same number of chromosomes helps, it doesn't really matter if they're fused together.",
"That is: I can line up these two just fine:",
"ABC... | [
"Could you go into a bit more detail about how genes \"line up\"? That whatever process it is by which genes line up isn't affected by the fusing of two chromosomes into one sounds fascinating."
] | [
"Should this be a not-uncommon occurrence, then? Do we know of species (hopefully mamallian, or at least non-insect) in which differing numbers of chromosomes is just a common variation across the species?"
] |
[
"Is there a limit to the size of rocky planets?"
] | [
false
] | null | [
"There is a fundamental limit on the ",
" of rocky planets based on how material compresses. When I say \"size\" I mean how much ",
" the planet takes up, as measured by the planet's radius or diameter. See ",
"Figure 4 from S. Seager et al. 2007, Ap.J. 669, 1279",
". After a point, adding more mass would c... | [
"Yes but it isn't precisely known what the limit is. Above a certain size, it will be massive enough to attract interplanetary gas and become a gas giant. This is thought to occur around 7 Earth masses."
] | [
"what if it is so far away from everything else that it is large but, effectively, has \"no\" gravitational pull or influence on gas?",
"Is there a point that it becomes so large that it would collapse on itself? I imagine it would depend on the density. If it was a giant, jupiter sized ball of talcum powder vs. ... |
[
"If you placed a plant or tree in an airtight container, would it remain preserved like a human body?"
] | [
false
] | Was thinking about this last night. My instinct tells me yes, but my friend seemed convinced that it wouldn't be the case. Assume no sunlight is reaching the plant. | [
"What do you mean \"preserved\"? Certainly an airtight (and thus, maybe more importantly, watertight) container would slow decay, but neither a human body nor a plant would be completely preserved. Sequestering anything that dies from the natural elements (fresh air, moisture, other organisms) will likely slow d... | [
"Well, I know that I have a distant aunt that was buried in a fully air-tight glass coffin. She died in the 50's I believe, and my family has a mausoleum. You could go and see the body and it is exactly as it lied when she died. I was just wondering if sequestering a plant in an airtight glass container with no sun... | [
"If this is the case then it is unlikely she was just placed in an airtight coffin. She would have gone through an embalming process which preserved her body. Even this is not perfect and she will not be looking so great in another 50 years or so."
] |
[
"What are researchers and scientists primarily doing on Antarctic missions? What have been the most significant discoveries or advancements from this study?"
] | [
false
] | null | [
"One of the most historically significant discoveries made in Antarctica was the work of Joseph Farman (and many others after him) on the ozone hole over Antarctica and its relationship to CFCs. Farman begin collecting ozone readings in Antarctica in 1957, although his work was largely dismissed by the scientific c... | [
"There's really a myriad of different research projects being carried out there, from biological surveys on and in ice, to sub-ice hydrological mappings. One big thing is Paleo climate and Paleo biology (scientists drill into the ice to look at chemicals and life forms that got trapped in it thousands of years ago)... | [
"One of the other things that is done in Antarctica is the Meteorite Search. Antarctica doesn't likely get any more meteorites than anywhere else int he world, but because it's largely white, and meteorites are largely dark, they become much easier to find.",
"Yet another research project going on in Antarctica i... |
[
"Is it possible for plants/fungi or other organisms lacking brains to have a sense of consciousness?"
] | [
false
] | My friends were having a debate about being vegan. One of them was saying based on animals having consciousness we shouldn't infringe on the rights of animals because they have consciousness. Then my friend decided to play devil's advocate, he said plants have a type of plant intelligence and awareness and therefore pe... | [
"Nobody has the foggiest idea what \"consciousness\" means."
] | [
"Short answer: When it comes to questions about consciousness, the answer is usually \"who the hell knows?\"",
"I typed up a rambling conjecture for a \"long answer,\" but realized halfway in it was much more suited to Philosophy or ",
"/r/PhilosophyofScience",
". In the case of plants, the answer is almost ... | [
"Define consciousness. "
] |
[
"How do astronomers decide what star systems to search for potentially habitable planets?"
] | [
false
] | null | [
"Well, I'm not sure they rule out any stars, but our detection abilities are still limited.",
"So",
"An earth like planet isn't going to make much wobble or block much light from it's parent star. Our best bet is from smaller dimmer stars for the search for earthlike worlds.",
"Additionally, Earth only became... | [
"I daresay they might also start with the closest stars and work their way out."
] | [
"The other answers here are a bit incomplete. What stars are observed depends on the telescope used. Some exoplanet searches focus on the brightest stars (in apparent magnitude) because those are easier for followup research, but the chances of finding a planet are lower because of the small number of such stars; o... |
[
"How did bees evolve to have stingers?"
] | [
false
] | I doubt many predators are eliminated this way. Bees have exoskeletons so I would expect that they wouldn't be able to use them against other bumblebees, and they are social animals. I know that humans know to avoid bees, but are there other animals that know to avoid them? I just can't see how they are helpful. | [
"Stingers are present in large groups within the suborder Apocrita, including many social and solitary wasps, and also many ants. Basically the stinger is a modified form of the ovipositor (egg laying organ, which also means that only females have stingers) and may or may not have venom. Stingers are used for both ... | [
"They can use their stingers against smaller predators like wasps. And exoskeletons can be penetrated at the joints quite easily, and are far less likely to kill the attacking bee in the process as opposed to e.g. human skin.",
"Being a social animal does not mean that they are peaceful and never fight. It just m... | [
"Stingers can be used in defense of a hive. All it takes for some bumbling animal is to get stung trying to attack a hive, and maybe it will avoid hives next time it finds them. It is an evolutionary positive to have defense or hives would be eaten for their honey more often. If the hive survives, so does the qu... |
[
"If a picture is taken of a regular mirror from the nonreflective side of a two-way mirror, what would the picture show?"
] | [
false
] | I've searched for the answer but never found it | [
"Your question was a little confusing for me, so here's a quick diagram to help me clear it up. Hopefully I got it right! ",
"Observer -> ",
"One-way mirror",
" -> Mirror",
"You would observe an effect similar to the ",
"infinity mirror",
" mentioned above. The mirror would display an effect similar to ... | [
"Also, the image you see would get greener and greener as it recedes \"away\" from you. Mirrors have an imperceptible green tint that is amplified by the repeated reflection. Even if you used two regular mirrors and could somehow see inside, the gradual dimming and greening effect would still be there. Mirrors aren... | [
"It would show two mirrors reflecting each other's image into infinity. "
] |
[
"What will happen if a UTI goes untreated?"
] | [
false
] | [deleted] | [
"First what is a urinary tract infection (UTI). A UTI is essentially just inflammation of the urinary lining in response to an infection. When detecting a UTI we generally are looking for two things: bacteriuria (the presence of bacteria in the urine which generally does not have detectable bacteria) and pyuria (si... | [
"It really depends on a complex interplay between the bacteria causing the infection and the person it is infecting.",
"An otherwise healthy person stands a very good chance of eventually clearing the infection on their own, though it would likely be uncomfortable until the infection was resolved.",
"Someone wh... | [
"This is an awesome answer. I'm especially happy to see that you included the concern that we are over treating UTIs. Even many practicing physicians are actually under the impression that most UTIs will become a kidney infection if left untreated.",
"I would add that sepsis from a urinary tract infection is usua... |
[
"(How) do we know that other observed galaxies aren't made of antimatter?"
] | [
false
] | Given that we're really only looking at electromagnetic signatures when we image other galaxies, couldn't a significant portion of them be made of antimatter without being close enough to ordinary matter galaxies to decompose? | [
"While space is relatively sparse of matter, it is still not empty. At the border of any region of space dominated by antimatter, we would expect to see extremely energetic collisions between its content and matter from outside."
] | [
"To back up your assertion, the ",
"Alpha Magnetic Spectrometer",
", launched in 2011, would have been able to detect if there were any such antimatter galaxies in the observable universe, and as of yet it has not. So the odds of there being antimatter galaxies ",
" in our observable universe are very low."
] | [
"In the milky way it seems density is on the order of 1 Hydrogen atom /cm",
" I would think that would be lower in the space between galaxies. That seems like a pretty weak signal compared to the stars in the galaxy."
] |
[
"Is lens blurring related to uncertainty principle?"
] | [
false
] | Taking a very specific example of bokeh, does the disk-of-confusion form because you can't (don't) exactly know the location of the point light source that made that disk? | [
"Those features are out of focus because the light rays from each point in the field were not focused to a point in the image plane. This does not have anything to do with the uncertainty principle.",
"The diffraction limit of light and the resolution limit of a lens does have to do with the uncertainty principle... | [
"Personally I find this ",
"picture",
" a perfect explanation of what \"out of focus\" means."
] | [
"The uncertainty principle has to do with the fact that observing tiny particles by ",
" messes with their behavior and collapses their waveform. These lens effects have nothing to with a quantum mechanical function."
] |
[
"Is the concept of a \"multiverse\" falsifiable and scientific?"
] | [
false
] | Within the context of science, we cannot say there is a "god" because that would not be falsifiable. If we claim there is no god, and then find a way to prove god's existence scientifically, then we can falsify the theory that there is no god. Does this apply to the multiverse? If we claim there is one universe and sud... | [
"The answer depends on what you mean by \"multiverse.\" To my knowledge there two main distinct uses of this word in science and popular science.",
"The first refers to the many worlds interpretation of quantum mechanics, which, like all other interpretations of quantum mechanics, is currently not falsifiable. Ho... | [
"Well there's also the third kind where there are actually multiple universes, but not as part of the many-world interpretation of QM or as distant regions caused by inflation. I think it's part of M-theory as 3D branes."
] | [
"The first refers to the many worlds interpretation of quantum mechanics, which, like all other interpretations of quantum mechanics, is currently not falsifiable.",
"I think Sean Caroll makes a great point in his recent blog post on the MWI. It clearly ",
" falsifiable. Just show an objective collapse of a wav... |
[
"Why and how does light propagates as a \"sphere\"?"
] | [
false
] | Don't know if the question is clear enough, so let me try to explain. Let's imagine a balloon with a lot of dots painted on it (a finite amount). When I inflate it, the dots are going to be more and more spaced. Why doesn't this happen to light? | [
"This has more to do with what your source is doing. A laser doesn't propagate outward as a sphere.",
"Spherical propagation, more fundamentally, this is a statement of flux in a 3 spatial dimensional universe. If you look at something like Gauss's law, often factors of 4pi appear, because when we're talking abou... | [
"It does, actually. The intensity of the light diminishes more and more as you get further out from the source."
] | [
"Going back to OP's analogy, in some cases it's as though all the dots on the balloon are within a microscopic distance of each other. When you inflate it, they'll still be further apart, but just because of how they started they won't be ",
" apart."
] |
[
"Are pessimists less likely to be affected by placebos?"
] | [
false
] | null | [
"in short, ",
"yes",
". It should be noted, though, that not all of the placebo effect is \"mind over matter\" and \"expectation of results\". It has a number of components (some of which come from the physician/researcher, not the patient/subject) and would be better described as \"non-specific effects\".",
... | [
"Also worth reading about is the ",
"nocebo effect",
", which is when the patient is harmed by his belief that the medication will do him harm."
] | [
"That is correct. Thank you for helping to clarify. "
] |
[
"Why is it that when a person gets kidney stones, he/she has a risk of getting stones again?"
] | [
false
] | From what I understand, those who got kidney stones have a high chance of getting it again. Is there a difference in the risk of getting stones before that person got the stone? | [
"One interesting reason is that the crystalline formations of minerals can be \"contagious\" - i.e, as a crystal starts forming, more and more oxylate gets \"locked\" into position and forms a bigger stone. When it finally breaks off, some might be left behind, serving as the \"seed\" for the next stone.",
"Since... | [
"There will be certain conditions that led to the original stones formation. So if those conditions continue, there will be a high probability of it resulting in more stones forming. If you want to stop further stones, you need to work out what was causing them and try to change things."
] | [
"Really depends on the cause of the stone. Contrary to popular belief there are many different types of kidney stones. For some it could be a malfunctioning endocrine system, for some it’s diet, for some processing of certain foods isn’t happening. There are even cases of people who take a certain antibiotic and co... |
[
"In a molecule like Formaldehyde, the Carbon is said to be sp2 hybridized. Is the oxygen also sp2 hybridized? or does the C-O sigma bond occur between an sp2 lobe from C and a horizontal p lobe from O?"
] | [
false
] | [deleted] | [
"It's not justification, it's a way to determine hybridisation because for most molecules, VSEPR predicts configurations and shapes that have been experimentally confirmed. "
] | [
"The oxygen in formaldehyde is sp2 hybridised. A good way to determine hybridisation in general is to look at the prediction made by VSEPR. In this case, the oxygen has three equivalent orbitals in a trigonal planar structure, two of which contain lone pairs. This structure is only possible with sp2 hybridisation. ... | [
"in my experience, VSEPR is a much simpler model than orbital hybridization and should not be used as a justification for orbital hybrids.",
"as an example, vsepr model predicts that any 4 electron group atom should have an sp3 hybridization, but atoms with lone pair electrons deviate from this model. VSEPR doesn... |
[
"What is the \"I don't care\" medicine they give you before a surgery? Is it usually the same thing or does it depend on the anesthesiologist?"
] | [
false
] | [deleted] | [
"I worked in a hospital pharmacy for awhile. Versed, or midazolam, is a common benzodiazepine given before surgery or intubation. Also could be fentanyl, the two are often used simultaneously."
] | [
"usually the agent that is used to actually put you to sleep is an inhaled drug like isoflurane. the above drugs are used to prevent pain and reduce anxiety."
] | [
"Versed. Causes temporary amnesia."
] |
[
"Is there an inverse placebo effect? I.E. a patient's disbelief in drug efficacy can literally make a drug less effective?"
] | [
false
] | Is there such a thing as an inverse of the placebo effect? How extensively has this been studied? What I'm asking is how much people's negative expectations can actually the efficacy of a drug. And if there's a term for this. I'm asking about the nocebo effect, in which people report negative effects from an inert subs... | [
"Um, if most of your answer is correct, it should be summarized as \"No, definitely not.\" You answered the OP's question as no, but said it was \"yes\" in the first sentence."
] | [
"Yes, absolutely.* In addition to positive and negative expectations, a placebo can be affected by zero expectation. If you give someone a real placebo and tell them so, and they believe you, they will experience no effect. If you give them a real drug, tell them it's a placebo, and they believe you, the effect the... | [
"Any source on this?"
] |
[
"What is the risk for developing long term effects or other severe side effects from COVID 19?"
] | [
false
] | From what i understand long covid seems a really important issue but the coverage on it seems to have dropped the last few months. Also i dont understand why the odds of getting myocarditis from the mRna vaccine gets so much coverage especially to young people but the odds of getting myocarditis from covid is never men... | [
"It seems that about 30% of those who get light cases of covid 19 become long haulers to some extent. I don’t understand why people don’t get the vax and think they will be fine if they get it. That’s close enough to 1 in 3 people that I got the vax as soon as I could. ",
"But humans are terrible at estimating ri... | [
"The vaccine isn't even approved yet, there are reasons to be skeptical of taking it. I'd also like to know where this 30% number comes from and if it includes possible issues cause by experimental medical treatments."
] | [
"The 30% number is reported in many places, including the CDC. It seems to be pretty world wide. It’s typically people who got a lighter case, most often didn’t spend any time in the hospital or had any real treatment, other than the basics to reduce symptoms. ",
"Some of the long haul symptoms are reduced/damage... |
[
"Can substances be dissolved in a gas?"
] | [
false
] | null | [
"Supercritical fluids aren't gases..."
] | [
"The answer is no. Gasses cannot dissolve substances because solvation involves intermolecular interactions and these are practically non-existent in the gas phase short of the occasional bumping into each other.",
"Someone pointed out super critical carbon dioxide which is interesting to think about. If you thin... | [
"Would it still have the invisibleness of a gas?"
] |
[
"If the reason testicles are kept outside the body is that sperm can't survive at the body's internal temperature of 37C/98F, why do people who live in places where the ambient temperature is routinely higher than that have no trouble breeding?"
] | [
false
] | null | [
"At an ambient temperature higher than body temperature, and at 100% humidity, there would be no evaporative effect. So sweat would only cause dehydration. A person would require some external cooling source to survive and/or cool their nuts.",
"Edit: getting a lot in my inbox. What about this place? What about t... | [
"Is there a limit where the sack can't regulate the temperature?"
] | [
"A person would require some external cooling source to [..] cool their nuts.",
"I am now eager to rig such a contraption using parts procured from the local PC hardware shop's watercooling section... With a working prototype I'll throw a kickstarter to tempt punters into the new comforts of desk jockeying !",
... |
[
"Since gunpowder burns well and quickly, is it technically high in calories?"
] | [
false
] | null | [
"This depends on your definition of high calorie content and what you are comparing it to. A calorie is 4.184J. According to Wikipedia, gunpowder contains 3 MJ/kg. ",
"For comparison animal and plant fat contains 38 MJ/kg and carbohydrates are 17 MJ/kg.",
"Check out the table of common energy storage materia... | [
"It is not that high in calories probably less than sugar. It is just that it is able to release all of it's energy very fast. This is an Energy versus Energy/Time situation. Gasoline has about as much energy as its equivalent weight in fire wood but gasoline burns faster than fire wood."
] | [
"The term you might be looking for is ",
"energy density",
". For comparison you can also look at the ",
"energy densities of food",
". For the record - MJ/kg is equivalent to kJ/g."
] |
[
"Is there a conceivable way to diffuse sound in outdoor venues that hasn't been manufactured yet?"
] | [
false
] | null | [
"You may have noticed that major highways near residential areas typically have some form of concrete wall between the road and the buildings. The purpose is to reflect car noise. ",
"As a side note unrelated to your question, I have spent much more than 30 minutes in an anechoic chamber and noticed no unbearable... | [
"You'd probably have better luck having monitors using noise-cancelling tech to broadcast the counter-signal of the concert, cancelling the soundwaves for anyone outside the concert while not effecting those inside the radius of outward facing speakers.",
"Though in all honesty this would be prohibitively expensi... | [
"I did notice that. Maybe they are too expensive for small venues?? And municipal building guidelines ",
" be prohibitive for big walls."
] |
[
"I have a glass of water, and I want to cool it with ice as fast as possible. Should I use crushed ice or regular cubes? Why?"
] | [
false
] | [deleted] | [
"Crushed ice will have a larger surface area to volume ratio, so it will cool your water more quickly with an equivalent amount of ice."
] | [
"To add to that, stirring the water will ensure that you don't get a buffer-zone of chilled water around the ice-cubes. (though convection will also make movement in the water, stirring is more efficient)"
] | [
"Although by stirring you'll be putting more kinetic energy into the system. So just stir slowly"
] |
[
"Does the dark side of the Moon overall receive more light than the light side?"
] | [
false
] | null | [
"By a very very small amount (about 0.5%), because when there is a new moon and the far side is illuminated, it is closer to the sun than when there is a full moon and the near side is illuminated."
] | [
"But on the other hand, during a new moon, the near side is receiving light reflected from the entire Earth, which has a much higher albedo than the moon. Isn't that a larger difference? (especially because the far side does ",
" get this benefit during Full Moon)",
"Then there's also lunar ecplises, which only... | [
"No, with the small exception of lunar eclipses."
] |
[
"Does the oxygen from water oxygenated the blood just like oxygen from the air does?"
] | [
false
] | null | [
"A flair is used to categorize a post into one of the categories shown in the message above. There are also instructions for how to add flair."
] | [
"Hi Johanakerblom thank you for submitting to ",
"/r/Askscience",
".",
" Please add flair to your post. ",
"Your post will be removed permanently if flair is not added within one hour. You can flair this post by replying to this message with your flair choice. It must be an exact match to one of the f... | [
"what are flairs and how do i use them?"
] |
[
"Is .3 [recurring] times 3 equal to .9 [recurring]?"
] | [
false
] | null | [
"Yes. (1/3)*3 = 1."
] | [
".333...=1/3",
".999...=1"
] | [
".333...=1/3",
".999...=1"
] |
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