title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
|---|---|---|---|---|---|
[
"Why can't we put Cyanobacteria on planets to make them habitable?"
] | [
false
] | [deleted] | [
"Very broadly speaking, we can. I'd say there are three broad categories of issues with this idea:",
"We don't want to 'settle' a planet with our bacteria before we have an idea of whether there is pre-existing life. Knowing that there is life on another planet would be a huge discovery, and once you contaminate ... | [
"Cyanobacteria have been successfully grown in simulated-Martian conditions, so it's theoretically feasible, however with algae and cyanobacteria the problem is always scale and how things behave differently when scaled-up. A cyanobacteria colony grown in a jar does not necessarily indicate at all how it would grow... | [
"We don't want to 'settle' a planet with our bacteria before we have an idea of whether there is pre-existing life.",
"To add one more point: it is (relatively) easy to introduce life to a planet. It is (relatively) difficult to eradicate life on a planet. Thus, if you aren't sure which you'd like to have, you'... |
[
"If a males testicles are removed before puberty occurs does the male grow to be the size they would have been if the testicles were still there?"
] | [
false
] | To add to my question, would the removal of the testicles before puberty cause the person to be uninterested in sex after they would have otherwise gone through puberty? | [
"I can't quite say much with regards to humans, but as an owner of ferrets one of the interesting facts about them is all ferrets in, at least in Canada, legally must be Spayed/Neutered.",
"This has interesting side effects, as the operation is done when the ferret is very young. One effect that has been document... | [
"To the “uninterested in sex” question: I took a course called “Sex and Endocrinology” and one class we had a discussion about the ethics of whether sex offenders (rapists, molesters, etc.) should be required by law to take either a pill or injection to stop the synthesis of testosterone (T). As of right now they h... | [
"I am by no means an expert on this subject but I read in a book titled \"Mutants\" by Armand Leroi that \"Boys that are castrated before puberty grow up to be tall\"( page 199) and also discusses the Italian Castarti who where a troop of singing men that where castrated. The entire book is a fascinating read abou... |
[
"Could an asteroid have an atmosphere?"
] | [
false
] | Can relatively small objects like asteroids have atmospheres, provided that they were massive enough to have the necessary gravitational pull to keep said atmosphere from escaping? Is there a lower limit to this? Could an object the size of a basketball have an atmosphere? | [
"If the gravity there isn't strong enough it'll just float away."
] | [
"It is possible that the largest asteroid, Ceres, has a very sparse atmosphere. We will know more when the Dawn probe arrives. Most of the asteroids are too small to have an atmosphere. The second largest, Vesta, does not."
] | [
"If Ceres doesn't have an atmosphere, could we provide one by, oh, I don't know, opening a cylinder of massive gas? (",
" 6 for example?)"
] |
[
"Biologists say that humans have 10x more bacteria in their body than human cells, but how can this number be possible?"
] | [
false
] | null | [
"Bacteria are much smaller than human cells, roughly 1/10th the diameter in size. Imagine a cantaloupe compared to a blueberry or a grape to get a rough idea of their relative sizes. There's a very large population of bacteria living in your gastrointestinal tract, which is where that 10x number usually comes from.... | [
"If I remember correctly, roughly 30% of your excrement during a bowel movement is bacteria. But technically, that's not inside your body. Bacteria inside of your body is a serious infection. ",
"We are a flesh tube with a mouth at 1 end, an anus as the other. Food is never ",
" of us."
] | [
"Well, a 10 cm sphere is 1000x larger than a 1 cm sphere, so I thought it fit pretty well as a rough comparison."
] |
[
"[Medicine] Is there a scientific reason why medical personnel will tell someone in a critical state to \"stay with me!\" or similar requests?"
] | [
false
] | You see this all the time in the movies, and I once talked to a guy i met at a pub who said he was a paramedic and told me that sometimes patients will just "let go" and die, and that you have to WANT to survive. I was wondering if there's any medical/scientific literature about this effect. Why ask a patient to "stay ... | [
"On the whole, we really don't do this. In fact, we often do the opposite and actually put the patient to sleep. A critically injured individual arriving in the resuscitation room may be semi conscious, agitated, and unable to lie still for procedures or scans; worse they may not be able to protect their airway and... | [
"This question came up in a first aid class I recently took. The answer was that it was strictly to make it possible to observe symptoms.",
"Symptoms such as blurred vision, dizziness, nausea, loss of speech, and anything the patient might bring up can all be indicative of different problems and you can't diagno... | [
"This is just my speculation, but I think that this is probably done more often \"in the field\" (outside of a hospital) than actually in the hospital.",
"I've reasoned that one reason it's done is to stimulate a patient and therefore generate more sympathetic tone (the part of your nervous system that kicks to g... |
[
"Is it possible to develop our night vision?"
] | [
false
] | Let's say, if someone is locked in a dark room during several months (with food & water), and then gets out, would his eyes be able to see in the dark at night? I read somewhere that when you stay a long time (months..) in the dark, it could take at least 1 day for your eyes to be able to see in bright light. Does it m... | [
"It is not that easy. While our eyes do in fact get used to seeing in dark places it won't be easy for them to see perfectly. We have a series of light sensitive cells inside our eyes. Some of them get \"burned out\" when looking at bright light, but they quickly heal when no longer exposed to light. This causes us... | [
"Since mutation is COMPLETELY random, this could take antwhere from a single generation to millions of them. This is a common misconception that living in certain conditions will actually somehow affect the outcome of gene mutation, but the only thing it can change is how often can it happen."
] | [
"Only if that advantage actually helps... If they're in a mansion filled with food and genitals, and nothing for them to fall to their death off of (or otherwise get harmed), then it wouldn't really change one way or another. Also, if the members of the group who can see better feed and protect the others, who do p... |
[
"What are the solar eclipse glasses made from?"
] | [
false
] | They were reasonably priced, but in the UK not many people are bothering to stock them as it's only a partial eclipse. They're upwards of £40 now online, and there's no guarantee that they'll get here by Friday. I actually have some glasses of my own from the eclipse 15 years ago, as well as using a floppy disk which i... | [
"It is a very bad idea to try to improvise solar viewing filters. There are certain wavelengths in the NIR range that the lenses in your eye will focus but the rods/cones in your retina are not sensitive to. It is possible to do severe damage while looking at something that does not even seem overly bright."
] | [
"It is possible to do severe damage while looking at something that does not even seem overly bright.",
"Comparable to not feeling exposure to gamma rays from radioactivity and hence not seeking safety before the vomiting sets in (and such)."
] | [
"I've discovered that the silvery glasses are most likely made form Aluminised Mylar film, which reflects up to 98% of the light hitting it. £5 for a 1m x 1m square.",
"Someone must know what they're constructed from, because they're essentially plastic film and cardboard and definitely do not cost £5 to make. Th... |
[
"If I swallow a large piece of food, will I still digest all of it?"
] | [
false
] | I've have some idea how food moves around inside the body and some about the timeframes, but I've no idea of the capabilities and mechanics of the system. Are large pieces of food broken into smaller pieces chemically somehow and then digested? Or does digestion happen layer-by-layer, no matter the size of the object? ... | [
"Digestion has a few phases. Your mouth begins the first part, where saliva breaks down starches. The stomach is next, which has two primary methods of digesting food: acid mostly kills bacteria, but does help to break down the structure of food. Pepsin is a very active digestive enzyme in the stomach that is activ... | [
"This is spot on. I'd highlight that digestion occurs both mechanically and chemically to break something down from the size of food you eat to the size of individual molecules that can be absorbed into the bloodstream and/or lymph.",
"Just mechanically breaking food into smaller pieces is not typically enough to... | [
"This is a good question!",
"An educated guess is that it would take a bit more time to digest, and the extra calories would be stored as fats. The digestive system has evolved to eke as much nutrition out of food as it can.",
"If calorically useful food was expelled as waste, obesity would probably not exist, ... |
[
"What would happen if a GRB shot off and passed through a black holes event horizon."
] | [
false
] | If a GRB goes through an even horizon of a black hole, is it sucked away or can it go through? | [
"The event horizon is the absolute limit beyond which nothing can escape. Geometrically, there are no paths which leave from inside the event horizon. Gamma rays are just part of the electromagnetic spectrum and don't behave any differently from light in this case."
] | [
"A gamma-ray burst is just a flash of very high energy light, and just like any other light (or anything else for that matter), it can only cross the event horizon in one direction. Once inside, it stays there."
] | [
"Black holes don't suck. The radiation falls into the black hole or is lensed around it."
] |
[
"Can gravity be altered on specific objects?"
] | [
false
] | [deleted] | [
"By taking a reasonable guess at OP's level of understanding about gravity from their text, starting the conversation with Einstein's field equations would be at best useless and at worst damaging.",
"First you need to understand how gravity relates to mass. This rough concept doesn't change when moving to genera... | [
"As the gravitational effect of an object is tied to its mass, you can only alter the forces by changing the mass. While not at fancy as some of the concepts you propose... consider trying to lift a gallon of milk: If you drink some of the milk, the remaining milk in the gallon container is easier to lift as the Ea... | [
"Newton's equation only describes how \"gravity\" works. It does not describe the actual force and why it works as it does. Einstein got a lot closer to it and his equations take over in situations where Newton's don't work, such as describing the orbit of Mercury. ",
"But even that doesn't describe the \"fo... |
[
"The temperature outside is below freezing (~28 F) and it is raining. Why isn't it snowing?"
] | [
false
] | null | [
"I prefer visuals and a bit more science behind what type of precipitation to forecast during winter events.",
"This is a skew-t log P diagram",
" for a sleet event in Wilmington, Ohio on January 17, 2004. A weather balloon was launched and this shows the temperature, dewpoint temperature, and wind speed and di... | [
"In all likelihood, it's not that cold where the rain is forming. Freezing rain frequently happens when there's a warm front - so warm air is aloft but the cold air is trapped near the surface. So the droplets start as pure liquid - then they fall through the cold layer, and become supercooled. They don't actually ... | [
"http://science.howstuffworks.com/nature/climate-weather/atmospheric/question302.htm"
] |
[
"Does E=mc^2 apply to dark matter/energy?"
] | [
false
] | In referencing the new Planck data, people keep citing that a certain percentage of our universe is dark matter, while another percentage is dark energy. If energy can be converted to mass by E=mc and at least some mass is matter, then how can dark energy and dark matter be quantified separately? Does the equation only... | [
"There appears to be a source of mass we cannot observe, other than that we don't know much about it. We know it is there from the \"extra\" gravity coming from what looks like empty space in galaxies. We call this \"dark\" matter simply because it does not interact with light.",
"The expansion of the universe as... | [
"If energy can be converted to mass by E=mc2 and at least some mass is matter, then how can dark energy and dark matter be quantified separately?",
"Energy cannot be ",
" to mass -- rather, mass is a ",
" of energy. All mass has energy.",
"What they are saying is, some percentage of the total energy of the... | [
"To expand on Moltencheese's comment:",
"We have a rough estimate of the amount of visible matter in the area of the universe we can observe. This also accounts for 'normal' energy",
"Based on its gravitational effects holding galaxies together, we can roughly estimate the amount of extra mass there is in the f... |
[
"Are non-ferrous metals affected by magnets or magnetic fields at all?"
] | [
false
] | I know the short answer is no, that only ferrous metals interact visually with magnets (i.e. paperclips being stuck to magnets). My question though is that are non-ferrous metals such as aluminum, copper, mercury, etc affected by magnetic fields at all? If so, what are the effects? | [
"I know that in certain minerals, they can be diamagnetic or paramagnetic, depending on electron states and compositions, but they very rarely hold an induced field, rather the electrons will align with an induced field, but immediately go back to having a more or less random alignment after the field is removed. \... | [
"Diamagnetism and paramagnetism are still interactions, just at a much lower scale than ferromagnetism. ",
"Here's a frog being levitated in a strong magnetic field through diamagnetism.",
"Edit: also, note that it's not just iron that experiences ferromagnetism; nickel and cobalt also are ferromagnetic."
] | [
"Wikipedia and Google will have the answer for you (as will your library), but I can sum it up a bit.",
"Diamagnetism - Applying an external magnetic field to something that is diamagnetic creates an opposing field within the material. Usually considered \"non-magnetic\".",
"Paramagnetism - Magnetic spins with... |
[
"Why do we feel emotions more strongly in the chest?"
] | [
false
] | Or more specifically, the heart. For millennia, humans have associated loss, love, fear, grief and even rage with the heart. Why is that so? If the brain is the seat of consciousness, shouldn't we feel emotions more strongly in our heads? What gives? | [
"We don't actually know 100%, but the best theory seems to be that increased stress hormones cause some rapid changes to happen in the body. A wave of feedback floods the nervous system, raising heart rate, forcing the stomach and several 'less essential to immediate survival' organs to shut down. ",
"The vagus n... | [
"Finally, my time to shine!",
"Scientist here - I study the brain-heart connection and am using it to try and find some objective / 'uncheatable' ways to assess concussions. The vagus nerve does generally control parasympathetic states, however, the innervations to the heart and carotid artery monitor your blood... | [
"Vagus is part of the parasympathethic system, which does the opposite of what you've said. Sympathetic system is responsible for increased heart rate, bowel movement and secretion inhibition and vasoconstriction, muscle vasodilation etc. ",
"It's true that all this happens in intense emotional states."
] |
[
"how is anxiety related to gerd?"
] | [
false
] | null | [
"Chronic conditions typically have a negative impact on a person's daily life as they have to constantly manage it. Reduced quality of life can easily lead to anxiety and depression. I don't think there's a lot of evidence that hyperacidity directly causes changes in the brain that would lead to anxiety."
] | [
"It’s possible that changes in the gut flora contribute to mental disorders by causing chronic inflammatory activation of the immune system. I don’t know to what extent, if any, GERD affects the gut flora."
] | [
"GERD is not the same as hyperacidity. GERD is the refluxing of gastric contents into the esophagus. Lowering the acidity of stomach contents can help to relieve things by making the stomach acid less irritating to the esophagus, but the root cause is the reflux itself.",
"Anything which increase gastric pressu... |
[
"Are baby teeth more susceptible to tooth decay than adult teeth?"
] | [
false
] | null | [
"Yep! Mostly because children don't really brush their teeth the proper way... Babies are susceptible to tooth decay because of drinking milk from bottles. Milk contains lactose which is a disaccharide derived from glucose and galactose and the bacterial plaque metabolizes it resulting in the accumulation of organi... | [
"wow thanks. how did you find this question?"
] | [
"cool. So I'm guessing you're some bio genius?"
] |
[
"How do instincts work?"
] | [
false
] | I watched a documentary called The Queen of Trees which focused on the relationship of fig wasps and a fig tree. A wasp will lay eggs inside a fig, and when the eggs hatch the new wasps know to grab some pollen, head out and find another fig tree. How do they know what they are supposed to do? They couldn't have learne... | [
"Essentially, from what I understand, the wasps do not \"know\" to do this. Through the long evolutionary timeline, the wasps who laid their eggs in figs were the ones with a better chance of survival. In the same way, the young wasps who grabbed the pollen right out and went to the other fig trees also for whate... | [
"Instincts as you describe them are simply very complex interactions of lots of simple instructions. Take for example the instinct to open your eyes. It is easy to understand that one neural pathway exists that rewards any stimuli from the eyes, hence making you want to open your eyes. Let's make that instinct more... | [
"It's a pretty good answer, but there need not be other populations of wasps trying other fruits. All that is required to get a species of wasps on the path to exhibiting this behavior is for one momma wasp from some population somewhere to select fig trees as there egg laying location instead of what that species... |
[
"For the Chemists and Chefs of /askscience. Does a certain range of heat cause butter to homogenize with water?"
] | [
false
] | Simmering my Rice-a-Roni, after sauteing the dry mixture, initially produced a noticeable sheen of oil droplets on the surface of the liquid. After a little heat and stirring the mixture seemed to homogenize. This cloudy state remained briefly until my future meal suddenly "sprang up" the oil beads across its surface... | [
"Butter consists of butterfat, milk proteins and water. The butterfat is the fat from milk. This fat is a triglyceride which a molecule made up of a polar section the head, and a long tail that is nonpolar. The nonpolar tails are much larger, and nonpolar molecules don't dissolve in a polar molecules like water.... | [
"Cook here since you asked. I don't know about the science of it but I can tell you that if you have two liquids that do not normally mix (e.g. oil and water) and you whisk or stir like mad, you will form what we call an emulsion (which may not be scientific name) which is an even mix of both. For example we would ... | [
"Interesting, there was certainly a delay between stirring and the separation of the oil and water. Speaking from my limited knowledge of chemistry liquids and gasses have very similar properties. Would the water being on the edge of reflux put the water/oil mixture into a state of excitement closer to a true gas a... |
[
"Silly question from a non-science guy: Are there folks who actively research/test/explore what are already held to be rock-steady theories?"
] | [
false
] | [deleted] | [
"Sure.",
"Experiments are often repeated. Either as a teaching tool or because someone thinks they have a new angle/technique to test something or because equipment has gotten more sensitive and an experiment can be done to a greater degree of accuracy.",
"It is quite common for \"settled\" science to be re-te... | [
"That's a GREAT question, not a silly one.",
"I think there are two types of answers in physics:",
"What is the value of science if nobody cares about the results? If the results of one study are not used in another, it's pretty much worthless in the first place, no better than the answer to a trivia question.... | [
"Science builds on itself. In order to make the next step, you need to repeat methods used for previous theories tons of times.",
"For example, I'm working on the receptor for a pathogen. The initial work in the field was done back in the 1950s, everyone in the field for the last 60 years has copied what worked i... |
[
"How much can our muscles \"memorize? And for how long?"
] | [
false
] | null | [
"Unfortunately not. Muscles don't have the capacity to store commands, but your brain is incredible at optimizing things that are common to your everyday life. ",
"Language, walking, holding a pen (or anything for that matter) are all learned skills and thus are not automatic skills, but your brain would have op... | [
"You're right, I'd just like to point out that our memory for motion/actions is longer than our recall for factual knowledge. There is certainly a limit, and it can certainly be lost (ex. a stroke victim forgetting how to walk).",
"Musicians don't forget how to play after being away for a few months, it's quite c... | [
"I actually play guitar and the reason I was a bit skeptic about putting a date on was because it seems songs I really know, I don't forget. Some songs though, ones I'm not very comfortable with I can forget in months time. But that's probably because I haven't associated the song with motion but rather the factual... |
[
"Medicine - What actually happens to a patient when they are put under anesthesia?"
] | [
false
] | I'm just a curious high school student who is wondering what the science behind anesthesia is. Why is it that you don't feel pain when you're sleeping? ...or is it even a state of sleep? I really have no idea... Thanks for any explanations :) | [
"General anaesthesia is when you are \"under\", as opposed to local which blocks pain in a local area. Under general anaesthesia you aren't sleeping because during normal sleep you still respond to pain stimulus and will move about. So it is actually a medically induced coma. A combination of drugs are used to do d... | [
"So in the case of analgesia, what is happening to the body that makes these responses to pain quit?"
] | [
"There are many different types that work in different ways;",
"http://en.wikipedia.org/wiki/Analgesic",
"An old, common and powerful class is the ",
"opiods",
" which work by attaching to opioid receptors found in the brain, spinal cord, and gastrointestinal tract. When the drugs attach to certain opioid r... |
[
"\"For reasons even a chemist is hard-pressed to explain, ring shaped gasoline molecules are higher in octane\", is this still true ?"
] | [
false
] | I'm watching a Modern Marvels episode about gasoline, and they're on the bit explaining about hydrogen fracking, and this line stood out. This episode is probably 20 years old now, does it still hold true ? If so, why ? | [
"Well, I'm only an undergraduate ChemE student, and it may hinge upon the understanding of what is meant by \"octane\", but I feel like I can explain this pretty easily. ",
"First, definition: By octane, I assume you mean octane number, and I interpret octane number to be broadly how high the initial energy must ... | [
"That line doesn't make very much sense. Gasoline is a mixture of several molecules, mostly hydrocarbons of varying sizes and structures. One such hydrocarbon is octane, an 8 carbon linear chain. By definition octane is not and cannot be a ring. ",
"My guess is that they may be saying that ring structures found i... | [
"I love ",
", but their writing isn't always terribly...technical.",
"When the narrator says \"octane,\" what they are referring to is ",
" As I explained in a reply to another comment on this thread, ",
"[Octane rating] is based on a comparison to iso-octane and n-heptane. For example, 91 octane-rated gaso... |
[
"Could plants grow from the light of propane lanterns? Would the extra CO2 help growth?"
] | [
false
] | [deleted] | [
"Couple of other comments have hit on this, but a gas lamp is probably not going to output nearly the intensity of light needed for plant growth. I was using high intensity fluorescent bulbs in a make-shift chamber in a lab, and unless they were <24\" from the leaves, there wasn't enough photosynthetically-availabl... | [
"It may not be a good idea as 1059fmwmal points out, but would the plants actually grow?",
"This",
" contains a graph of visible-spectrum emissions of a propane flame.",
"This",
" has charts that show how plants, algae and their pigments respond to different wavelengths of light.",
"The propane flame is s... | [
"Using gas mantles this could be feasible. A standard 2 mantle camping lantern is around 800-1600 lumens, a 24 watt CFL for comparison is about 1600 lumens. The color temperature of a gas mantle is about 2800K by the red blue ratio alone, however, these mantles do not produce light by black body emission alone and ... |
[
"Why is an oversupply of electricity a problem?"
] | [
false
] | [deleted] | [
"There's no way to store power on the scale of national grids. There just isn't the technology to contain that much energy on a short term basis. Therefore, the grid is in a constant delicate balance where operators try to generate ",
" as much power as is needed at one particular moment. Too much or to little an... | [
"If you burn 1 unit of fuel to produce 1 unit of electricity but you consume 0.75 units of electricity you have just wasted 0.25 units of fuel.",
"You charge your clients for consumed electricity so, you just lost money.",
"That's the simple economic perspective.",
"There is also the environmental which is th... | [
"Well, we can do it practically with hydro, we just don't have enough of it relative to what we need. "
] |
[
"Is there an algorithm to compute \"truly\" random numbers?"
] | [
false
] | Reading through the on random number generation it talks about how pseudorandom number generators use a key value and perform a number of operations towards it to make it appear random. An algorithm that is deterministic must not be able to generate truly random data due to the fact the determinism must produce the sam... | [
"Theres no such thing as an algorithm for generating truly random numbers. To get randomness, you can't start from something that isn't random.",
"Therefore, generating truly random numbers has to stem from hardware, not software (",
"http://en.wikipedia.org/wiki/Hardware_random_number_generator",
"). For i... | [
"To have random results you gotta have random inputs. In the end algorithms are sequences of instructions and so are always determinstics. As long as all the inputs are known, the result will be the same."
] | [
"\"Anyone who considers arithmetical methods of producing random digits is, of course, in a state of sin.\"",
"-- John Von Neumann"
] |
[
"Why can we ignore the imaginary part of the simple harmonic motion displacement equation?"
] | [
false
] | If you derive the displacement of a mass on a spring from the first principles F = mx''(t) = -kx(t) then you get the equation x(t) = Acos(wt) + iBsin(wt) where A and B are real constants and w is the angular frequency (sqrt(k/m)). Why can we eliminate the second half of the equation? Is it ever used? My working for the... | [
"Once you get to the general solution you have to get the particular solution by applying the initial conditions. Say you know the position and velocity at t=0. This first means that A has to be equal to the initial displacement x(0). Looking at the derivative you have",
"X'(t=0) = iBw",
"So unless you have an ... | [
"Have you taken a course in linear algebra? It will clear up a lot of your confusion, but we have two solutions:",
"y1 = e",
" , y2 = e",
"The solutions are called linearly independent (which for now means \"not constant multiples of each other\") and any other solution is a linear combination of these two so... | [
"It's not that you just ",
" the imaginary part. A \"solution\" is valid only if it satisfies the original differential equation (which A cos(wt)+i B sin(wt) does) but also has to satisfy the initial/boundary conditions. If the initial conditions are all real, then B must be 0 to satisfy them. Physics don't need ... |
[
"Do photons have radii?"
] | [
false
] | null | [
"Nope, they're point particles, like any other elementary particle."
] | [
"What does that exactly mean? Does that mean protons, neutrons, and electrons also don’t have a radius? If they don’t, then how do we know they have mass? I know their mass comes from Quarks and gluons and iiirc the Higgs Boson, but how can they be a point with mass? (Not photons)"
] | [
"Does that mean protons, neutrons, and electrons also don’t have a radius?",
"Protons and neutrons are composite particles, so they have nonzero size. But elementary particles are treated as pointlike in quantum field theories.",
"They can be treated as point particles but still have mass, there's no issue with... |
[
"If a person is starving to death, is there a point in which food intake will not save the person?"
] | [
false
] | null | [
"Great question! I agree with Ag-E, if a person is literally starving to death, energy exertion related to energy intake is not the reason for mortality rather the body being unable to digest the food due to damage is the culprit. If a person is chronically undernourished, their body will start to use protein as th... | [
"Yes, I think so though I don't know of any hard numbers. Also it's likely that it's not an issue of energy for absorption being greater than energy needed, but rather an issue of the body cannot absorb the food itself due to 'damage' (hypoplasia, really) to the digestive tract.",
"As to how intravenous nutrien... | [
"Are there any known cases of a disorder in which the body started >doing this when it wasn't necessary? ",
"Type I diabetes. glucose sits out in the bloodstream but there isn't an uptake signal (insulin). so the body assumes it's starving, and some krebs cycle derivatives (where much of fat and protein get turne... |
[
"After watching a film at the cinema yesterday my vision was 'flickery' for short time afterwards. What could have caused this?"
] | [
false
] | null | [
"Please observe the subreddit ",
"guideline",
" - ",
"No asking or giving medical advice",
"and",
"Personal experience can not usually be explained scientifically with any confidence and will invite speculations/anecdotes."
] | [
"Where do you suggest I ask this then?"
] | [
"It is against Reddit's Terms of Service to provide medical advice, however, if you are just curious about your own personal experience, you may want to try out ",
"/r/askreddit",
" or ",
"/r/DAE",
"."
] |
[
"Would gaming glasses actually help your eyes or reduce eye fatigue during long gaming sessions? (Gunnar Glasses for example)"
] | [
false
] | null | [
"I just watched the ",
"\"Gunnar Technology\" video",
" on their webpage, and holy smokes they need a new pr/advertising team. FRACTYL?! I-FI? IonIK? I feel like I'm reading a marketing brochure for snowboards in the 90s.",
"The only thing that sounds plausible to me is eyestrain reduction, which, in their na... | [
"That's what's called \"confirmation bias\": in this case, your brain cannot accurately gague the eyestrain during a session with or without the glasses, so you assume that they must be doing something positive.",
"Personally, I'd be very interested in a rigorous paper on these glasses."
] | [
"This was an awesome response- thank you! "
] |
[
"Would a tattoo with radio opaque dye work?"
] | [
false
] | Was looking at a clear radio opaque dye in the OR today (it was Omnipaque I think) and I got to wondering if a tattoo with it would be feasible. The dye only shows up under X-Ray and otherwise looks like water. Would it be possible to get an "invisible ink" tattoo in this way? | [
"Tattoo ink consists of ",
" and a ",
". The pigments are solid particles which are not absorbed by the body. The carrier is there to sterilize and to form a suspension making the tattoo process easier to practice.",
"If you injected a dye (dye = solution, not a solid pigment) one would expect the dye to ev... | [
"There are 2 kinds of commonly used radiopaque dyes used in medicine. Barium compounds are used in the GI tract and is a white, chalky liquid. It is safe in the GI tract, but it can cause severe inflammation if it gets into other tissues. This is why it's avoided if there is a good chance of immediate intestinal su... | [
"It certainly would not be invisible on the skin normally. it would look like a faint white, patchy tattoo, or scar. Look at ",
"This",
" example of a UV ink tattoo for reference of what I mean. The tattoo process changes the skin enough that it will be noticeable in most environments even if done with \"transp... |
[
"Is the water at the bottom of the ocean more \"condensed\"?"
] | [
false
] | Is the water in the deepest parts of the ocean more "condensed" due to the pressure? Also say you manage to get the water at the deepest parts of the ocean in a container, what happens to that container once you start bringing it back to the surface and open it? Does the water shoot out due to it no longer being under ... | [
"Water is not technically incompressible, but it doesn't compress much. Pressure increases ~20 bar per 100 meters of water depth, so on a ",
"scale like this one",
" you can see that the density changes (and thus volumetric changes for a constant mass) are relatively small, though you would also have to account... | [
"Water is surprisingly incompressible. More or less like steel.",
"To answer the second part of your question, water contains dissolved gas, and so the water under great pressure at the bottom of the ocean can contain more gas than water under less pressure near the surface. As you bring up a container of water t... | [
"I love this sub. Thanks, man"
] |
[
"Does Monty Hall Problem solution apply to Italian gameshow?"
] | [
false
] | Mathematicians of the internet, here's a question that's been bugging me for a while... So there is this famous gameshow in Italy: You get assigned one of 20 numbered boxes, that contain different money prizes ranging from 0,10€ to 500.000€. You don't know what's inside yours or any other box. During the whole show yo... | [
"The key ingredient that makes switching best in Monty Hall is that the host removes a losing option. The host adds his own knowledge of which door is bad into the mix. Since this does not happen in this case, all the remaining boxes have the same odds of being the best box. So there will not be any benefit to swit... | [
"Right, I wasn't really sure about it. Thanks a lot!"
] | [
"In this game, the Monty Hall analysis does not apply and it does not matter whether you switch boxes at the end or not. You can not increase (or decrease) your expected winnings by switching. Your expected winning at the start is equal to the average of the 20 prizes; your expected winning at the end (when only 3 ... |
[
"Are claims made by supporters of a paleo diet actually valid claims supported by scientific evidence?"
] | [
false
] | I'm mostly talking about the idea that this is the way we should be eating because it was how the paleolithic man ate, and our biological evolution didn't have time to catch up to our change in sources of food once the settling, domestication of animals and all that began. I'm aware that this question was asked a few t... | [
"The field of nutrition is far from being a scientifically rigorous one, hence the reason why you're not going to get a straightforward answer - because there is none as of yet.",
"The human body and its interaction with the fuel it consumes and how that affects health and robustness is complex and it's not simpl... | [
"And that vitamins have something to do with it, although we're not sure what."
] | [
"There is a fair amount of scientifically rigorous evidence in the field of nutrition, but there is also a lot of gaps and unknowns.",
"Even if we knew everything about nutrition that there is to know, there is still the matter of gauging how it's going to effect a human's biology on a daily, hourly, etc. basis. ... |
[
"My SO is wondering, if global warming is real, why is it snowing in our town in Louisiana for the first time in decades? She thinks this is an adequate disproval of climate change."
] | [
false
] | null | [
"Hi GusTheSquid 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 fol... | [
"'Earth Sciences'"
] | [
"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",
"Earth sciences FAQ",
"If you disagree with this decision, please send a ",
"message to... |
[
"How does matter come into existence?"
] | [
false
] | I once saw a simulation of fluctuation in quantum vacuum, in the video they explained that even in vacuum there is no absolute vacuum. So I got the idea of matter coming into existence and disappearing just as quick. What are these fluctuations? are they particles or is it energy? Is it neither or both? | [
"Right, but they have to be virtual particle/antiparticle pairs in order to satisfy various conservations laws.",
"\"Virtual\" and \"anti\" mean different things. They're not interchangeable."
] | [
"Particle/antiparticle pairs can come in and out of existence for no reason at all. The reason is the time-energy uncertainty relation, which basically says energy can come from nothing as long as it doesn't \"live\" for very long."
] | [
"There is a little bit of energy 'everywhere', you could think of it like the surface of a lake on a calm day. It looks flat but when you get up close you will notice it does jiggle a bit.",
"Saying 'a virtual pair is created and destroyed' is analogous to noting that occasionally the random movement of the lake ... |
[
"How can RNAs with internal loops be stable?"
] | [
false
] | [deleted] | [
"To answer your first question.\nThey way you imagine RNAs is not correct. They are not just floating around. The nucleus is not like a water balloon with some DNA, RNA and Protein mixed in. The nucleus is much closer to a gelatinous mix of densely packed DNA, RNA, proteins, nucleic acids, salts and some water. So ... | [
"Thank you so much! I'm taking biochemistry and this really helped! Couldn't stop thinking about it haha"
] | [
"I might add that RNAs do have complex secondary (and higher order) structures, sometimes crucial for their roles. For example, internal ribosome binding site (IRB) is a fricking secondary structure which is recognised by proteins and binds a fricking ribosome into a middle of RNA.",
"As for unpaired loops bindin... |
[
"Is there any evidence that the strains of Covid prevalent in the US this summer tend to produce milder, shorter symptoms?"
] | [
false
] | The reports of the illness I read in 2020 were typically along the lines of "holy shit that was awful!" and this summer, I get much more muted reports. Does the large-scale data collected by public health reflect my own personal/anecdotal impression? Also, is there data providing any sign that rates of mortality, and... | [
"First off, omicron, the dominant variant since Christmas, is certainly both more contagious and less deadly than prior versions. The current subvariants of omicron are likely of similar contagiousness and deadliness to the initial omicron strain from Christmas. Even so, severity of illness and deadliness is lower ... | [
"Smell and taste can disappear and seemingly never return. It’s not clear whether these issues are permanent or just long lasting. Also, some variants can cause reinfection of those that have had even recent infections. New vaccines are on the horizon that target less mutagenic parts of the virus, and may be mor... | [
"In UK, losing taste and smell is now a low percentage for omicron and subvariants.\nSore throat and headaches are the biggest recorded symptoms over here.\nEven fever is no longer a main symptom",
"https://www.bbc.com/news/health-62161604"
] |
[
"How can you identify if an atom can make 5 or 6 bonds in a molecule?"
] | [
false
] | I'm an 11th grader and I'm really confused on which atoms can make more than 4 bonds. For example in the class work there's a question that asks the structure of xenon tetrafluoride and my chemistry teacher said it can go up to 12 electrons. I understand that hybridization has something to do with it, but my teacher di... | [
"There's no trivial way to determine whether a main group element will break the octet rule. I'm afraid you'll have to get comfortable with identifying common examples by practising questions. You can then work out their structures as you would any other simple molecule - by counting the electrons (even if more tha... | [
"Yes this is very true. Though most taught approximations in chemistry sort of get it right and provide some insight. d-orbital hybridisation is as good as saying “elements higher in the table break the octet rule” and provides you with no more information into the true mechanisms at play."
] | [
"Thank you. Strange as the link works fine for me."
] |
[
"Are electric cars really more efficient?"
] | [
false
] | I understand that electrical engines are generally upwards of about 80% efficient. However combining mechanical losses, grid transmission losses and thermodynamic efficiencies/losses through current combined power generation methods does an electric car utilise the chemical energy produced through coal and other source... | [
"does an electric car utilise the chemical energy produced through coal and other sources better than an average Internal Combustion engine does from petrol?",
"Yes. The greater size, and other efficiencies resulting from the fact that they were designed for the specific purpose of converting chemical energy into... | [
"One key note to consider is manufacturing energy. People forget to consider whats involved in manufacture of the car, Battery cells manufacturing, especially lithium is intensive even disposal has a impact with electric as cells may only last 5-10 years.",
"I like to remind people that a hybrid economy car that ... | [
"In a conventional combustion engine the heat is just waste heat.",
"If the car has a turbo, not ALL of the heat is wasted. But, most of it still is. :P",
"People just don't understand how incredibly wasteful cars are with their power.",
"Not only is the internal combustion itself very inefficient, but the dr... |
[
"If I were run through with a 20 micron needle, would I feel it?"
] | [
false
] | [deleted] | [
"While 20 microns is small (.02 mm) you would feel it if you where run through with it although it would mostly feel like a pinch. The reason for this is on the way through you the needle would still likely hit a nerve cluster somewhere. Now if the needle only punctured the surface of the skin it is less likely tha... | [
"The biggest risk would be contamination of sterile environments. Even if the needle itself was sterile and you sterilized the skin surface prior to puncturing (like you do with normal injections) if you actually punched through the intestinal walls you could absolutely carry bacteria from the gut into the sterile ... | [
"Secondary question. If someone was to be completely run through with said needle, how much damage would it do? As in, say it went through his stomach/intestines/liver, what would happen?"
] |
[
"Why is it so hard (or impossible) to keep our hands steady?"
] | [
false
] | I mean, I don't have particularly shaky hands, but if I shine a laser pointer across the room, the dot isn't going to be stationary. Somewhat related (or maybe not), why is it so hard to control our bodies in general? For example: typos, mistakes when playing instruments, messing up inputs in games, etc. Would improved... | [
"When it comes to keeping limbs steady, the issue is due to the nervous system. You see, to keep your hand steady, you need to use muscular force to keep the hand up. The muscle flexes because the brain sends impulses down the nerves which excite the muscles and the muscles contract. This is a discrete phenomenon, ... | [
"I think a better ELI5 explanation would be:",
"Your muscles are made of many little muscle strands (like a rope is made up of small rope fibers). When you hold your hand up not all fibers are being used at the same time (for that you need to hold extra weight in your hand). When some of the fibers get tired, oth... | [
"If I can do short ELI5 explanation: Muscles have many small fibers, where their state is binary, either pulling, or relaxed. More force means more fibers pulling, but they always pull all the way or not at all. When you try to hold your hand up, these fibers contract and loosen few at a time making it jerk a littl... |
[
"Why do (many) humans and so many animals enjoy being pet/stroked?"
] | [
false
] | I tried posting this Q a while ago but the phrasing was a little garbled - sorry for repeat. I'm curious about what purpose petting/stroking serves. A lot of people (but of course not all) enjoy non-sexual caresses but also a lot of animals - on Reddit, of course, we see all kinds of dogs and cats and and . I'm also cu... | [
"The specifics involve us having a lot if sensory nerves that are only stimulated enough to really feel if they're triggered in sequence. Since those nerves are a few centimeters apart it takes a nice slow scratch or a stroke to trigger this. ",
"The general answer is that humans are extremely social colony anima... | [
"Small alternative answer that covers some non-social behaviors:",
"Some animals use rubbing or brushing as a way to transfer their familiar scent to objects and friendly animals, as a way to locate their territory. Making rubbing feel good is a simple evolutionary mechanism to make them more likely to do it.",
... | [
"surely there's a reason we've evolved...",
"Remember that evolution has no goals or purpose. Things that are beneficial to reproduction are more likely to persist in a population, but that does not mean they always do, nor that every aspect of a creature must benefit it in some way."
] |
[
"Why doesn't it get twice as bright when I turn on a second lightbulb?"
] | [
false
] | null | [
"it does, in terms of energy, but you don't perceive it that way: humans see in logarithmic scale, which means if you want things to get twice as bright, you have to square the intensity! It allows to have a good contrast perception in dark or bright environments similarly."
] | [
"The relation of brightness to intensity is not quite logarithmic - a logarithmic relation would be where the ratio of a just-discriminable change in intensity (ΔI) is a constant fraction of the background intensity (I). Instead, the ratio changes gradually over the range of intensities, being larger for small inte... | [
"square the intensity",
"...or the ",
" of the intensity? Seems to me one would not \"square the intensity\", one would multiply the intensity by the square of the desired ratio, which would be 2",
" = 4."
] |
[
"Why do I sneeze when I look at something bright?"
] | [
false
] | [deleted] | [
"This is called the \"",
"Photic Sneeze Reflex",
"\" and it isn't 100% clear why it happens. Check out the wikipedia for more information. The theories on this largely boil down to - \"in some people, light signals are interpreted by the brain as nasal irritation, perhaps because some neuronal connections went ... | [
"I've seen speculation that photic sneezing and synesthesia are linked",
"http://typewriting.org/2003/08/23/synaesthesia_and_sun_sneezing/"
] | [
"You could also look for information by searching the subreddit before you post."
] |
[
"What is the estimated total population of uncontacted peoples?"
] | [
false
] | The Wikipedia article ( ) gives some partial estimates. Many are listed as "unknown" so a total estimate won't be very presice, but even the order of magnitude would be intersteting. Is it thousands, tens of thousands? | [
"Survival International, a nonprofit rights group based out of London, has been quoted in the Washington Post as well as other publications that there are maybe 100 un-contacted tribes worldwide. No mention of population though.",
"Here is a link of current campaigns. ",
"http://www.survivalinternational.org/tr... | [
"Yes, but the word \"contact\" in this context has a different meaning than you are thinking. It's confusing, but when referencing indigenous peoples \"uncontacted\" really means \"without an established relationship with modern society.\" It also is applied only on an individual level, which causes strange stateme... | [
"Wouldn't taking a picture of them from an assumed aircraft with the people pointing to the camera be considered \"contact\"?"
] |
[
"How does the clitoris age?"
] | [
false
] | Both men and women have nocturnal tumescences, (erections) in their genitals while sleeping due to the lack of norepinephrine in the blood during REM sleep But as men get older NPT (nocturnal penile tumescences) decrese and if they ever reach full erectile dysfunction they stop completely My question now goes for women... | [
"Short answer is yes. Vaginal atrophy and dryness related to low estrogen plays a role in diminished sensitivity and ability to reach orgasm, as does reduced blood supply to the clitoris and lower vagina. Also, the clitoris is likely to be less sensitive than in earlier years, possibly due to reduced estrogen level... | [
"In a study on vaginal estrogen application, researchers found that local application of estrogen has been shown to relieve symptoms of atrophic vaginitis including dryness, irritation, itching and or dyspareunia. In addition, local estrogen therapy may have a favorable effect on sexuality, urinary tract infections... | [
"Does supplementing estrogen help with the difficulty orgasming? I know my mom got on it when she went through menopause and said positive things but I know anecdotal evidence is worthless."
] |
[
"How much better do batteries need to get in order to replace carbon fuels on ships and airplanes?"
] | [
false
] | From what I understand, the biggest producers of greenhouse gases outside of power plants tend to be the mechanisms of shipping, such as trucks, planes, and ships. A big barrier to shifting these transport systems away from carbon-based energy is that batteries can't produce the massive amounts of power needed to fuel ... | [
"For a back of the envelope comparison, the energy content per kg for various fuels can be found ",
"here",
". For gasoline, WP gives about 47 MJ/kg. ",
"The batteries in a toyota prius have specific energies along the lines of 0.12 MJ/kg. Even penalizing conventional fuels by noting that the energy efficienc... | [
"It does seem kind of low. I just ran the numbers given here ",
"http://en.wikipedia.org/wiki/Toyota_Prius#Battery",
"273.6 V * 6.5 Ah = 6.4 MJ for a battery back which weighs 53.3 kg",
"Probably the 53 kg figure includes the whole assembly rather than just the battery material itself"
] | [
"short answer: about 5 times.",
"compare ",
"energy density",
"petrol 47 MJ/kg",
"Li/air battery 9 MJ/kg",
"with planes there could appear a few other problems as to turbines, which couldn't possibly be replaced by elecric motors due to the function of fuel with expanding gases."
] |
[
"Do any planets in the solar system, create tidal effects on the sun, similarly to the moon's effect of earth?"
] | [
false
] | null | [
"Yes, but it's very, ",
" small. ",
"The reason is that while the tidal force scales linearly with the forcing body's mass, it also scales inversely as the distance ",
".",
"Let's scale our units so that the ",
". In those relative units, the rest of the planets' tidal forces on the Sun shake out as...",... | [
"Tidal force is the derivative of gravitational force with respect to distance. It basically measures how fast the gravity field is changing in an area, or the difference in gravitational force between the near and far sides of an object. Since gravitational force varies with inverse square, tidal force varies wi... | [
"Tidal force is the derivative of gravitational force with respect to distance. It basically measures how fast the gravity field is changing in an area, or the difference in gravitational force between the near and far sides of an object. Since gravitational force varies with inverse square, tidal force varies wi... |
[
"'Muamba was ..... dead for 78 minutes ...' How?"
] | [
false
] | How is it possible for someone to "die" for that long, and still have all his vitals in good shape after his heart was restarted? Wouldn't the brain be deprived of oxygen, as the blood will not be pumped in enough quantities, and die? The article Thank you | [
"It looks like he was given CPR by a trained professional, which will keep blood circulating and oxygenate the blood. The fact he was a trained athlete and in good overall shape probably didn't hurt either."
] | [
"He's correct, it seems they were forcing oxygen into him while his heart remained silent. Thank ... the great doctors and EMT's that saved his life."
] | [
"My second thought was that they also induced hypothermia to protect his brain function. I found some sources that mentioned it but not up to the usual standard of things I cite. It could have played a role though. ",
"http://www.soccerblog.com/2012/03/why-fabrice-muambas-plight-aff-1.htm",
"http://www.cartila... |
[
"Is there any study comparing the effects of smoking on health between sedentary and active smokers?"
] | [
false
] | [deleted] | [
"Hello!",
"While smoke induced pathologies are not my area of expertise, I have many colleagues at my institution that study COPD. There was ",
"a study in the European Respiratory Journal",
" which suggests that exercise reduces many of the problematic changes that happen someone smokes. Things like how elas... | [
"The health problem caused by cigarette smoke cannot all be cured by a healthy lifestyle... The cancer part for example. Cigarette smoke induces cancer because it contains carcinogenic components. Which means a componant that can induce mutations in your DNA. However hard you work out, you won't be able to repair m... | [
"The health problem caused by cigarette smoke cannot all be cured by a healthy lifestyle... The cancer part for example. Cigarette smoke induces cancer because it contains carcinogenic components. Which means a componant that can induce mutations in your DNA. However hard you work out, you won't be able to repair m... |
[
"What is the closest blackhole (stellar or larger) to Earth?"
] | [
false
] | I tried my google ninja skills but most of the information is a decade or older, and the then concensus candidate (V4641 Sgr) now has a disputed distance from us. So anyone here know what the current undisputed candidate is? | [
"The closest would be Cygnus X-1, which is ",
" a black hole, and it's about 8,000 light years away."
] | [
"Easier to see if it's closer."
] | [
"The black holes that we know about (or think we know about) are quite easy to see. They are part of x-ray binaries--the accrete matter from a companion star and shine brightly in the x-ray due to their accretion disk. ",
"The problem is knowing for sure that the object is a black hole and not some other compac... |
[
"Does the earth physically grow?"
] | [
false
] | [deleted] | [
"the earth is losing more mass via gases blowing away than it is gaining from in falling dust and rock. ",
"So taking into account the gains and the losses, Dr Smith reckons the Earth is getting about 50,000 tonnes lighter a year.",
"http://www.bbc.co.uk/news/magazine-16787636",
"your belief in something does... | [
"I agree with spthirtythree, but there is some accumulation of dust/rock from space, if that is what you are specifically curious about. As he says, however, it is more than offset by the loss of gasses."
] | [
"No, the Earth does not grow. In fact, it has a slight net loss of mass over time, as atmospheric escape of hydrogen (and a little helium) is the biggest factor in the Earth's mass change."
] |
[
"How are we able to observe and measure the half-life for certain elements?"
] | [
false
] | For example, Carbon-14's half-life is between 5,000 and 6,000 years. How do we know this? | [
"Somebody asked the same question yesterday, so I'll tell the same joke. A cop pulls over a speeding motorist and says, \"Sir, you were going 90 miles an hour back there.\"",
"The surprised motorist retorts, \"But officer, I was never planning on going that far!\"",
"A half-life is an expression of a rate. You ... | [
"It's best explained with an example.\nTake carbon 14. A 14g sample contains 6.02214179×10",
" atoms. Over one minute, you observe 1.378x10",
" atoms decay.",
"\nUsing fancy math, you know a half life means after n years, there is only half the amount left. ",
"This makes the function for how much stuff ... | [
"You don't actually have to sit and wait for the entire process. You can watch carbon decay over, say, seconds, weeks, or years and infer from that. The process is an exponential function so we can fit to that. ",
"We know experimental values enough to justify the theoretical proofs (which we also have from physi... |
[
"Why is it that human brains are able to \"auto-pilot\" certain commands, such as play the piano, video games, sports etc... But when we start to think about it, we completely lose rhythm?"
] | [
false
] | Examples of this : | [
"I suspect this article is what you are interesting in.",
"In short, there are different parts of the brain that are responsible for reacting to novel stimuli and carrying out tasks of habit. Different parts of the brain can suppress the activities of others. Very roughly, the more parts of the brain are involved... | [
"There are 4 stages of ability at any task:"
] | [
"The first video is a classic case of \"fire together, wire together\" wherein you develop an automatic response to a stimulus (e.g. you see a right arrow you tap the right arrow button) so you can reliably execute a complex task at a speed which would not be possible if you were consciously thinking of each indivi... |
[
"What's the difference between an X-ray laser and a regular laser?"
] | [
false
] | Would there be any? | [
"The wavelength of light that comes out of an X-ray laser is in the tens of nanometers, versus in the hundreds of nanometers that comes out of a \"regular\" (i.e. visible wavelength) laser and versus the hundreds of millions of nanometers that came out of their fore bearer the maser (Microwave-aser).",
"But, at t... | [
"Interestingly enough, in astronomy we often think of \"maser\" as a \"molecular laser\", where the amplification comes from (e.g.) molecular lines in H2O. But yeah, the original form was \"microwave\""
] | [
"Well the 21 cm line of molecular hydrogen is fairly snuggly in the middle of the microwave range anyways, so it's a little tomato, tomato (obviously this phrase doesn't work when typed... but you get my point)."
] |
[
"Why do the gold flakes in Smirnoff Gold neither float nor sink, but instead remain suspended in the liquid? Even if you move the bottle, they don't really move."
] | [
false
] | null | [
"The special thing about gold foil is that it can be made to be amazingly thin- sometimes descriptors like 1 atom thick get thrown around. That means the gold foil essentially has no weight. While gold is denser than lead and would sink very easily, with gold foil the resistance from the water dwarfs the force of g... | [
"Good thinking. This is, however, incorrect. Brownian motion of either the particle or liquid will be symmetric up or down, since the thermal fluctuations causing them are symmetric. Since there is still a net force (gravity) pulling down, the gold flakes will sink until they reach equilibrium at the bottom of t... | [
"Well, the brownian motion of the liquid migth keep the flakes from ever settling."
] |
[
"Re: Hydrogen Peroxide. Sometimes it reacts quickly and settles down, other times it creates a thick foam that sticks around for a while. What's going on here?"
] | [
false
] | [deleted] | [
"I'd say either temperature, old/new bottle, clean glassware"
] | [
"With the same conditions (concentration, solvent, stirring)? I'd guess the cleanliness of your glassware is at fault, any bits of iron oxide or iodide will catalyze disproportionation.",
"Whats the reaction?"
] | [
"Right. H2O2 eventually turns to water and oxygen gas if left unopened,"
] |
[
"Spore count using a Neubauer chamber calculation"
] | [
false
] | null | [
"So the concentration of spores in the diluted solution is",
"335 spores per 0.1mm",
"In the undiluted solution it is 500 times that",
"167,500 spores per 0.1mm",
"Converting to spores per cc gives 1.675x10",
"Given the concentration you can find the total for any volume using the equation",
"concentrat... | [
"First find how many spores you started with. How did you get 335? What does it represent? Then divide by 500."
] | [
"335 is the number of spores counted in 1 square mm"
] |
[
"Are there any limits to what science can explain?"
] | [
false
] | [deleted] | [
"Here is the wikipedia article on ",
"the scientific method",
" which you should read over.",
"You've asked two different questions here:",
"Are there any limits to what science can explain?",
"Are there any questions science cannot answer?",
"The second one isn't really what science is about. There ar... | [
"Yes, science is the ability to predict the outcome of an experiment based on previous measurements. If something is beyond our capacity to probe with a measurement, then it's outside of science right now. If future technology comes along that allows us to then measure such a thing, then it gets added to science. S... | [
"Science attempts to observe and explain the facts of the universe. However, I would argue (though some may disagree) that it is beyond the realm of science to answer questions of value. In other words, science seeks to understand the origin of the universe but is not interested in providing any kind of philosophic... |
[
"Is it possible to create a computer that uses base 10 or base n for computing, without quantum mechanics?"
] | [
false
] | [deleted] | [
"Some of the earliest computers were ternary computers, and ternary has some ",
"attractive benefits",
" over binary in terms of number representation. These benefits are offset by the structural complications of such computers.",
"http://en.wikipedia.org/wiki/Ternary_computer"
] | [
"Yes and no. We have no efficient means of storing things other than as charge, and charge only really allows for real-analog values and high-low binary.",
"We could always store things as \"base-ten\" by assigning 4 bits to every value, but there's no reason to do this.",
"Quantum computing has ",
" This is ... | [
"It's relatively trivial to construct a processor that will work with any positive integer base you would like; just interpret different voltage values. Storage of values in bases other than 2 is trickier -- our main memory (RAM) tends to use capacitors and we'd have to be careful to allow them to store and read ba... |
[
"Why does my phone camera show the heating elements on my stovetop to be a pink/purple colour when they appear red/orange to the eye?"
] | [
false
] | I imagine the camera is picking up the infrared light and shifting it to visible light, but my DSLR camera doesn't do this. What is special about a phone camera that makes it do this, and why the pinkish purple, which is at a part of the spectrum away from infrared? | [
"When the heat is shown as red to your eye, it is shown in 600 to 900 nm light also known as red. But there is a lot of light coming off in infra red 900nm and higher.\nThis infra red light is invisible but appears as violet to your camera. ",
"Tldr your camera is showing you light you can't see "
] | [
"The actual sensor on your camera is sensitive to a wide range of wavelengths, and it can't actually tell the difference between blue vs. red vs. infrared light. So to produce a colored image, there's a ",
"Bayer filter",
" in front of the sensor, which only allows light of particular colors to reach each pixel... | [
"When I was at uni we were using Infrared LEDs in circuits and we'd use our phone cameras to check if the LED was turning on - pretty handy"
] |
[
"Is the speed of sound directly proportional to density of the medium ? And if so, at how high density would sound travel faster than light ? If it's even possible."
] | [
false
] | [deleted] | [
"The speed of sound is inversely proportional to the square root of density of the medium (c~(1/sqrt(ρ) ) ), meaning the speed decreases with higher density.",
"However the speed increases with decreasing compressibility and as liquids and solids are much less compressible than in gases the speed of sound is muc... | [
"The medium with the highest speed of sound is any relativistic gas, with 58% of light speed."
] | [
"Speed of sound is related to density, and can be shown through experiment.",
"Put a 100m railway line down, then have someone simultaneously shoot a gun in the air and strike the metal rod- a person at the far end will feel the rod move before they hear the gun.",
"Sound is a pressure wave, so its speed depend... |
[
"What is the white light people describe as they are dying?"
] | [
false
] | [deleted] | [
"Seeing bright light in the manner you describe has been correlated with loss of consciousness experiences from lack of blood flow to the brain / high carbon dioxide. This is actually a suspected contributor to most near death experience phenomena like outer body experiences and life flashing before your eyes.",
... | [
"Thanks."
] | [
"No one is quite sure. Wiki has a couple of studies into what causes it:",
"'Strassman advanced the theory that a massive release of DMT from the pineal gland prior to death or near-death was the cause of the near-death experience phenomenon.'",
"'Research released in 2010 by University of Maribor, Slovenia had... |
[
"So, how does voltage actually work?"
] | [
false
] | Sorry if I come off as overly obtuse here, but I have been failing to grasp how this concept works for ages. I know that voltage is the 'potential difference across two points', but what does that actually ? What's the difference between electrons moving at 1v, 10amps, and 10v, 10 amps? What quality is it that they pos... | [
"Imagine pushing a cart down a road.",
" = how hard you push",
" = how rough the road is",
" = how fast you wind up going"
] | [
"A great analogy is a watercourse, just exchange electric potential for gravitational. A river flows downhill because there is a potential difference, just as an electron moves in a wire because of an ",
" potential difference. The steeper the drop, the faster the river. ",
"Electron drift velocity is linearly ... | [
"And ",
" "
] |
[
"How does a multimeter measure current and voltage?"
] | [
false
] | null | [
"Historically, electric potential (voltage) and current (amps) were measured using induction.",
"Electricity induces magnetism in predictable ways. This principle is how your doorbell works. You can build an analog galvanometer (which is a coil in a magnetic field). When current runs through the coil, it induc... | [
"Analog meters use the ",
"D'Arsonval movement",
". Basically, in 1820, Hans Oersted noticed that a wire carrying current would deflect a compass needle."
] | [
"You didn't actually answer how either of those devices measures volts or amps."
] |
[
"[Astrophysics] What evidence do scientists use to support the claim that the big bang caused our universe to emerge from a point smaller than a single atom?"
] | [
false
] | It's a wordy title, but that's all I'm asking. I hear this referenced often on scientific shows/movies/text books. How could scientists know that the universe emerged from a point smaller than a single atom? | [
"How could scientists know that the universe emerged from a point smaller than a single atom?",
"I don't know of any credible scientist who will say this. It is true that the early universe was very dense and, by extrapolation, the entire ",
" universe may have occupied a space smaller than an atom. However:"... | [
"When astronomers talk about the Universe that usually implies the visible Universe.",
"In the current paradigm of Physics, there are two leading models for describing the Universe. The Standard Model of particle physics and the Lambda Cold Dark Matter model. So a model for creating the Universe must be able to c... | [
"Well I most recently heard it from Neil deGrasse Tyson on the remake of Cosmos. I know he's very popular, but I don't know how credible his word is."
] |
[
"Is it unrealistic for a fighter to kick or punch with 1000 PSI in a fight?"
] | [
false
] | [deleted] | [
"Punching force for professional/Olympic boxers is usually between 500 and 1,000 lbs. For instance, on Sports Science, MMA fighter Houston Alexander generated around 800 lbs. force in a punch, and Rampage Jackson can deliver a 1,800 lb. punch. If you assume this is distributed over the face of an ungloved fist, y... | [
"No trained person just throws their fist at a person's jaw like a projectile, as if they had tossed a ball. A proper punch's power comes from the rotation of the puncher's core and is extended through their arm into the fist. A large percentage of a punch's power comes from the ",
" if done properly, and can hav... | [
"If a fist has a cross sectional area of four square inches and a mass of one pound, and the punch goes from 50 km/h to zero as it impacts the face over a distance of one inch, that is about 100 PSI. I estimated most of those numbers, it's not inconceivable that it's higher. I suppose if all of it was delivered thr... |
[
"Is gasoline entirely homonegous? If I buy Venezuelan gas at Citgo, is it any different than gas from oil from Saudi Arabia or Texas? Or does the refining process remove all differences?"
] | [
false
] | null | [
"Just a small correction to this, the octane rating is based on how the fuel acts compared to a fuel that was composed of n-heptane and iso-octane. So if you octane rating is 80, the fuel would act the same way (in regards to knocking) as a fuel mixture of 20% n-heptane and 80% iso-octane. It does not necessarily m... | [
"I won’t go into the question of additives – each brand of gasoline has its own formulation and ",
"mix of additives",
" – these will obviously make the product at the pump different from one brand to the next, but it is a bit of a trite and trivial answer.",
"There are, however, some variations induced by th... | [
"Since this is ",
"/r/askscience",
" you've gotten the chemical answers to your question but I'll add something about the market too. ",
"Gasoline is what's known as a fungible commodity, like non-organic whole milk. When one supplier has too much, it sells it as a generic product to another buyer. For exampl... |
[
"What can we make using the 6 elements in the /r/askscience logo?"
] | [
false
] | What sort of substance could we theoretically synthesize containing all (but not necessarily limited to) the elements in question: arsenic, potassium, scandium, iodine, neon and cerium? Slept through most of my high school chemistry, so if something exists in nature with those components, I'll take that too. | [
"Pretty much none. Neon is a noble gas which won't form compounds with much and definitely not with all of these at any reasonable energy. You might be able to squeeze everything but Ne onto some long molecule all as substituted atoms, but even that would be a stretch. The only compound that sticks out containin... | [
"I see... because of its \"nobility\", Neon refuses to associate with the \"commoner\" elements. "
] | [
"But goes off like a rocket when she parties with hydrogen"
] |
[
"If motion is relative, how do you determine which frame of reference experiences time dilation?"
] | [
false
] | null | [
"An observer will always measure time to pass at the same rate in their own inertial frame, and slower in other inertial frames.",
"You will observe the clock by the stop sign to tick slower than the one in your car.",
"Similarly, someone standing by the stop sign will observe the clock in your car to tick slow... | [
"Thanks for the response; I'm sure you're correct, but let me explain my own thought experiment that seems paradoxical to me. Hopefully you can help me see where I'm not thinking correctly:",
"Okay, so in the above case with the stop sign and the moving car, if we timed how long it took for the car to move from ... | [
"This is essentially a variation on the ",
"Twin Paradox",
"It's a very common gripe that people have when learning about special relativity"
] |
[
"What would happen if two gas giant type planets collided?"
] | [
false
] | So say something crazy happened with the Sun's gravitational pull, and Jupiter and Saturn collided. Being gas giants, how would that work? Would they destroy each other or would they merge to form a bigger gas giant? | [
"They would most likely merge. From the outside, the collision would look very \"soupy,\" for lack of a better word. They would appear to behave more like a thick fluid than anything else during the collision. "
] | [
"Neptune and Uranus ARE gas giants."
] | [
"Neptune and Uranus ARE gas giants."
] |
[
"How much faster/ stronger would wind be if trees and other obstacles weren't there to obstruct it?"
] | [
false
] | I know there are several variables such as geographic location. Also if there hasn't been a study regarding this, what are some of your best guesses and why? | [
"Near surface winds are strongly influenced by the thickness of the boundary layer at the base of the atmosphere. The effect of obstacles at the surface is characterized by the ",
"roughness length",
". If you removed the trees the wind at ground level would be faster but the quantitative increase would depen... | [
"There are areas of the world with very little ground cover. Salt flats, for instance, have near-constant, very-high winds. Hell, the Mojave, while not completely flat, has near-constant wind, though it wasn't very strong while I was there. Basically, the less trees and stuff you have, the faster wind will go. ... | [
"The most obstacle-free area you're going to encounter on the Earth has got to be the Ocean. If you're interested in wind, I suggest you read about the trade winds and westerlies and so on.\n",
"http://en.wikipedia.org/wiki/Trade_wind"
] |
[
"Are there any diseases that affect both plants and animals?"
] | [
false
] | If not are there any diseases that would be especially scary if animals could contract them? | [
" ",
", also known as the black bread mould, is one species amongst a small group of mould fungi that can parasitise both plants and animals. You've almost certainly seen it growing on old bits of bread and other foodstuffs you've forgotten about at the back of the refrigerator n' cupboard. Alongside growing on d... | [
"One controversial idea in my field: whether prions (infectious proteins) are taken up by plants, where they may be harbored and concentrated before later being consumed by the mammalian host, transmitting the agent.",
"The plants aren't specifically ",
" though they could still be considered ",
" with the pr... | [
"There are quite a few pathogens",
", scroll to Table 1. ",
"The short answer is yes, but a typical plant pathogen infecting humans is not that common, because pathogens usually establish a niche in a host where they like to live. Unless there is a good reason, like loss of its habitat/environment, pressure f... |
[
"Do noise canceling headphones harm your ears because it doubles the energy going into them?"
] | [
false
] | [deleted] | [
"Sound is a mechanical wave resulting from alternating compression and rarefaction of the medium it travels in. So when two waveforms cancel out, this means that mechanically, there is zero movement. So although on the outside it seems like they might add up, the motion of the air caused by the speaker in your head... | [
"Follow up question:\nWhat happens is destructive interference, right? I was wondering, what becomes of the energy in the two waves when they cancel each other out?"
] | [
"You're probably curious about how it can be that the noise cancelling headphones emit noise, and yet they don't emit sound into the ear. The reason, as you guessed, is that the sounds cancel out in your eardrum, reducing the perceived sound. So that raises the question... Where did that energy go that the headphon... |
[
"Is there any scientific validity to the technique of deep breathing as a cure to anxiety?"
] | [
false
] | Hi , I'm a long-time sufferer of anxiety. Popular 'wisdom' has told me that slow deep 'diaphragmatic' breathing is the best cure for this. Is there any kind of scientific evidence for this? | [
"Breathing deeply and steadily will reduce your heart rate and help relax constricted muscles in the chest and neck, reducing physical stress and helping to calm you down through lowering blood pressure. Additionally, breathing in such a way usually requires conscious effort and when a person focuses on their brea... | [
"I'm curious about how effective this is when the stressor that is making you anxious to begin with is your breathing."
] | [
"When people begin to ",
"panic",
" they tend to start breathing faster and with less volume (shallow) which decreases oxygen intake (think brain) and decrease carbon dioxide output. These both chemically amplify the feelings of panic and so slow deep breathing is the best way to resolve at least this problem.... |
[
"Could a solar flare knock out consumer electronics without an antenna?"
] | [
false
] | This came up as the result of the most recent solar flare which is supposed to have a coronal mass ejection which will hit the earth, or so my mom said. She's convinced that she needs to wrap her laptop in tinfoil so that it will be shielded from the solar storms. I'm highly skeptical that a small laptop without majo... | [
"I've been designing electronic circuits for 30 years. I'm not aware of any way for solar flares to damage electronic devices, except perhaps some sort of rare, fluke occurrence.",
"I think we get solar flares regularly, and I don't remember any case where TVs and radios were damaged on a widespread basis."
] | [
"I can understand the idea where the mass of solar flare hits the magnetic field of the earth, causing a sharp electromagnetic spike, which is picked up by, say, the Wi Fi antenna on a laptop and burns out the computer.",
"I can see all that in theory, but I'm a but skeptical in practice. So far no one has confi... | [
"Yes, short answer: don't worry about it."
] |
[
"What is Between Galaxies?"
] | [
false
] | null | [
"In terms of stars - there are very few stars between galaxies. If you were half-way between the Milky Way and Andromeda, you would see a sky that was almost completely black. Galaxies are quite dim overall, so you can't really see them unless they're pretty close. That means you'd only see the few nearest galaxies... | [
"Well, we can see other galaxies from here, so their light has to cross the gap. As far as planets and things, that's harder to say. We determine the existence of exoplanets by the way they interfere with the light from luminous bodies.",
"The intergalactic space is so large that the probability of detecting a ... | [
"There might be tiny amounts of molecules within them, but we can more or less talk about a vacuum. Then there are some asteroids or planets that got kicked out of their galaxies.",
"There certainly is light. Otherwise we wouldn't see other galaxies"
] |
[
"How does a warm-blooded fish evolve?"
] | [
false
] | Maybe a week ago there was big news about the first discovered , the opah. Apparently limited, localized warm-bloodedness is not unheard of in fish, but how does a full-blooded fish like the opah evolve? Is there some kind known evolutionary history (is that the word?) that led to it? Also, what is it about the opah's ... | [
"A couple things seem to be going on here. First, this fish isn't metabolically warm-blooded like mammals and birds, the heat comes from constant muscle contraction. That generates heat in any animal, it's just that this particular fish has a whole set of adaptations focused around trapping that heat in the body.... | [
"I'm pretty sure certain sharks, like Great Whites, have a similar system with their tail muscles. ",
"Thanks, Shark Week!"
] | [
"Was just about to say this! I believe Great Whites, and others in the family too (like Salmon Sharks IIRC) are \"warm blooded fish\" as well, but again they aren't warm-blooded in the same sense that we are. Rather than being warned metabolically, they have \"heat exchangers\". Pretty amazing, really, and a good e... |
[
"Would a diabetic with 100% optimal injections see any symptoms?"
] | [
false
] | So if someone injected the right amount of insulin at all the right times would they see the symptoms of the disease such as nerve damage? | [
"Sorry, I don't have a real answer for you, but my endocrinology professor loved to tell us that no one knew how to administer insulin perfectly, because otherwise there would be no symptoms (hypoglycemia, etc) or long term effects of diabetes despite the insulin treatment.",
"Just my personal guess - there may b... | [
"It depends. If you are talking about type 1 diabetes, the DCCT showed quite well that tight control of blood glucose with insulin prevented chronic complications. There's hope that the artificial pancreas, which monitors blood glucose and injects insulin and glucagon, might greatly improve euglycemia, however tria... | [
"Just for the record, to my knowledge, no one is working on a true artificial pancreas. All such attempts are being made with external insulin pumps delivering insulin subcutaneously and monitoring interstitial fluid subcutaneously, both from external devices.",
"A true artificial pancreas would have to be implan... |
[
"Has a computer ever done a mathematical proof?"
] | [
false
] | If not how far away from something like that are we? Could it be possible to have a computer brute force its way through a proof. Could you do supervised learning by feeding it lots of proofs until eventually it learns how to go about it? | [
"Sure. There are a few different categories of such things:",
"Computer-assisted computational proofs. The proof of the ",
"Four Color Theorem",
" is perhaps the best-known example of this; humans put together a framework to reduce the proof of the Theorem to a few thousand computations, then turned a compute... | [
"Hell, ",
"computers have coauthored papers",
"."
] | [
"A recent example of this is mentioned ",
"here",
", using Coq software to \"prove\" (verify) the Feit-Thompson Theorem."
] |
[
"Can a venomous animal be affected by its own venom if it were to enter its bloodstream?"
] | [
false
] | [deleted] | [
"Wow, 13 hours and no answers. I know for sure that venom is kept in special sacs to segregate it from the other organs, so I'm inclined to say \"yes\". (I don't normally provide layman speculation, but I guess it's better than nothing.)"
] | [
"This is an interesting question actually, and still under debate. \nHowever, giving the precise wording of your question, I would have to say that yes the snake would be 'affected'. "
] | [
"I too am curious. If a poisonous puffer fish for instance cut himself on a coral reef would it poison itself? Tetrodotoxin kills in seconds so I cant imagine an enzyme saving the fish in time."
] |
[
"Why do compressed air cans stop working and then regain a 'charge' after sitting for awhile?"
] | [
false
] | null | [
"There is also the significant temperature drop that occurs in the can. So the gas in the can at low temperatures reduces the pressure. As you increase the temp the pressure will increase in the can again allowing for more use. PV=NRT."
] | [
"Compressed air comes in a can as a liquid with a high ",
"vapor pressure",
". As the liquid sits in the can, a portion of it evaporates until the gas equilibrates with the liquid at a pressure much higher than the atmospheric pressure. When you pull the trigger, this gas escapes to equilibrate the internal p... | [
"Boyle's Law: (p",
"Rs",
"p=pressure\nV=volume\nT=temperature\nm=mass\nRs=a gas constant",
"When you spray, the mass in your can decreases. That means that the right side of the equation is \"off\" wich means the left side needs to compensate. The pressure decreases, the volume stays the same which means the ... |
[
"Do placebos effect some people more than others?"
] | [
false
] | I've seen many research papers that compare treatment effects to a placebo effect as a way of controlling for error. My question is, has there ever been meta-analyses type research conducted on these sorts of papers to determine if a placebo effect is just as likely to occur in any participant with regard to factors su... | [
"Well, it's kind of specific, but yes; here's a recent paper that suggests that people with a certain genetic variant are more likely to experience a placebo effect for irritable bowel syndrome: ",
"http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0048135",
"Here's another study, this time for... | [
"I think generally it is expected that ",
"personality types",
" play a bigger role in placebo than gender, age or race. A huge chunk of placebo is you believing you are getting a real drug - so people that will tend to think that this is the case will tend to respond. Age/experience could play a role in spec... | [
"I don't recall the specific reference off hand, but a placebo that causes side effects can cause increased placebo response. This untoward effects can be cues to suggest that you are in fact receiving the active medication in a study and so enhance the placebo response."
] |
[
"Is there something like an \"immediate concentration overflow\"?"
] | [
false
] | I'm a math undergraduate, and when I learn mathematics, there are times where I try to "switch a button" inside my head in order to gather and connect much more information at a time. Now, this might seem kind of weird, but it actually works. Do you remember the first time ever you drank a big cup of coffee or somethi... | [
"You may be inducing your adrenaline in order to think as best as you can. Doing so burns calories fast and if you're not prepared, you can easily burn out much the same as if you were to sprint for 20 metres versus jog for 100 metres. You are able to focus instantly and get into a zone, but our minds are designed... | [
"What do you mean by the last sentence?"
] | [
"Our brains aren't designed to laser focus onto something particular, such as being able to see telescopically or completely focus on calculating integers or something like that. Doing so would make us terrible predators. Our brains are constantly inputting balance, sight, sound, smells, tastes and more with each ... |
[
"How does water pressure in a siphon change over its length?"
] | [
false
] | If I have two barrels, one full and one empty, and I run a hose from the bottom of the full barrel over the lips of the barrels to the bottom of the second barrel and start a siphon, is the water pressure in the siphoning hose the same throughout the length of the siphon? | [
"Chemical engineer here. No, the pressure in the siphoning hose is not the same throughout. Friction between the tube walls and the fluid creates a pressure gradient from one end of the tube to the other. When there is flow, there is a pressure gradient. This formula sums it up.",
"∆p/ρ + ∆(v2)/2α+g∆z +F = W"
] | [
"I only have high school physics knowledge. But I am wondering if this would be an explanation, since I do not fully understand yours: ",
"The water in barrel A causes pressure (p=h",
"ρ). Since the air pressure on both sides is equal you do not have to take these into account. Now the water flow is caused by d... | [
"I don't think I understood your explanation. However, it's not really the effect Pikachusesks is describing.",
"The friction between the tube walls and the fluid builds a very thin layer of slow-moving fluid near the walls. This is called the boundary layer. As you travel along the pipe, slower moving fluid also... |
[
"Where does the energy come from in capillary action?"
] | [
false
] | involves a liquid travelling up a porous substrate, seemingly of its own traction. Where does the energy come from for this movement to occur? Should the substrate be considered an engine in the sense of energy transfer? | [
"The liquid that is drawn upwards is becoming bound (\"stuck\") to the substrate. Removing it from the substrate—by whatever means—requires at least as much energy as the gravitational potential energy that the fluid gained through the motion.",
"The motion is ultimately the result of electrostatic interactions ... | [
"The energy is positional potential energy that's effectively been there due to the initial conditions at the beginning of the universe.",
"What you're asking is analogous to asking where the energy of a meteor falling from outer space came from. It came from it just existing far away from the earth then falling... | [
"The Wikipedia entry didn't really explain it for me; it showed me the calculations that calculate the amount of energy involved, but it didn't really tell me where the energy ",
"."
] |
[
"Two of the same type of metals will bond together in space?"
] | [
false
] | Just got a interesting Snapple fact! Says that if two of the same type of metals touch in space they will bond together permanently! Why does this happen? And when it does how fast does it occur? | [
"It is called cold welding or vacuum welding. Richard Feynman explains it as such:\n\"The reason for this unexpected behavior is that when the atoms in contact are all of the same kind, there is no way for the atoms to “know” that they are in different pieces of copper. When there are other atoms, in the oxides an... | [
"What's really neat is that you can even watch this process happen in real time. For example when you take two small crystalline chunks of a metal and you put them together, when they touch in the right geometry, they will simply snap together to form one solid crystal, ",
"as shown in this video",
" for two na... | [
"The ideal scenario for cold welding is that you have two atomically flat and crystalline pieces of the same material that come together into the right orientation. In that case, welding is easy as it requires very little change in the position of the atoms that come together. ",
"Once you get away from this idea... |
[
"How come liquid oxygen is magnetic where as liquid nitrogen isn't?"
] | [
false
] | null | [
"An oxygen oxygen bond has two unpaired electrons. Unpaired electrons are responsible for magnetism. A nitrogen nitrogen bond has no unpaired electrons (because the two electrons that are unpaired in oxygen oxygen don't exist in nitrogen nitrogen). You might want to look up Molecular Orbital theory."
] | [
"I'd just add ",
"this graphic",
" since it illustrates what you're saying pretty clearly."
] | [
"Could you explain the graph? I have no clue what those arrows mean :/"
] |
[
"Does a black hole have a definite mass?"
] | [
false
] | Also, does it have a shape? | [
"Yes, for example the black hole at the center of the milky way has a mass of roughly 4.1 million solar masses.",
"More difficult to answer, black holes have an event horizon, that is the limit from which no light or information can escape. In a sense, the event horizon is the border of the black hole. The event ... | [
"A black hole has 3 measurable properties: mass, charge, and angular momentum. See ",
"the No-hair theorem",
".",
"If we think of the ",
"Event Horizon",
" as the boundary of a black hole, it is spherical for a non-rotating (no angular momentum) black hole and slightly oblate for a rotating black hole. Th... | [
"This depends on how the black hole formed and what it ate after forming. Since there is conservation of momentum (angular momentum included) it would have spin roughly comparable to the star it formed from and then we can continue to extrapolate that anything that was captured and falls into the event horizon also... |
[
"When undersea mammals are born, is it a rave for them to surface to breathe?"
] | [
false
] | I'm in the shower and wondering if dolphins and whales are born deep enough under water they will suffocate from lack of oxygen. EDIT: Race, not rave. Don't think things get that crazy for fish. Mobile won't let me update the title. Sorry. EDIT 2: Hey everyone, this is getting big by my standards and I'm very happy wit... | [
"Pretty much, yes.",
"Like other live-birth animals, they are provided oxygenated blood while in the womb, but after birth, they need to start breathing, and baby whales (for example) cannot easily float or swim. The mother will lift the baby out of the water to take its first breath. If the baby is born too deep... | [
"I wonder if all the \"dolphin saves so and so\" stories are the case of a dolphin thinking \"that poor baby\" and helping out even when its a 37 year old man"
] | [
"Yes. Dolphins instinctually save other mammals in distress, not just babies, but humans, dogs, and even other primates. This is because it is in their nature to help animals in distress (kind of like we do if we see a dog stuck in a river). ",
"EDIT: basically dolphins are good people. "
] |
[
"How discrete are the energy levels that electrons can occupy? If a photon of wavelength 800 nm was required to promote an electron, would a photon of 800.00001 nm suffice?"
] | [
false
] | Assuming that the electron is originally at ground state. I know that electrons can only exist in discrete energy levels, but what is the margin of error for the energy of a photon that an electron can absorb to be promoted? | [
"A similar question was ",
"recently asked",
". The answer is that states with finite lifetime do not have an infinitely precise energy. They have some width inversely proportional to the lifetime of the state."
] | [
"Definitely not random. There are multiple ingredients that go into it, including the matrix element for the possible transition(s), the coupling constant(s) for the force(s) involved, some kinematic/phase space factors, etc."
] | [
"Ok thanks! Are there any factors that determine the lifetime of states? Or is this spontaneous/random?"
] |
[
"G-force and Water"
] | [
false
] | If I was in one of those G-force simulators, and it was also filled with water (and obviously had an air supply), would I be able to withstand a much higher G-force than without the water? I would think that as I'm nearly the same density as water then the force I would feel would be negligible until very high G-forces... | [
"Buoyancy can offset the effects of G-force to an extent. The problem is that your body is not of uniform density. If you were of uniform density then yes, you could tolerate huge G-Forces when in a fluid of equal density.",
"As it is, the varying densities within your body lead to sheer forces.",
"As a non-med... | [
"I understand your reasoning that the water will lower the pressure on the body by a larger surface area but the overall force will be the same, in your original comment you seemed to imply the bouyancy \"cancelled out\" the G-force making it possible to withstand any G-force you wanted."
] | [
"From your wiki link, \"The accelerations that are not produced by gravity are termed proper accelerations, and it is only these that are measured in g-force units.\" ",
"I was not saying the acceleration is nullified by buoyancy I thought that you were implying that in the first comment."
] |
[
"How does data transmit through the air/WiFi?"
] | [
false
] | Moving through a wired system makes sense to me, but I never quite understood how that same action can happen in the air of my home. Feel free to go in depth. I understand quite a bit about telecommunications and computing. This is something I never personally researched, just "accepted." Also, do technologies like GPS... | [
"A quick brief on computer networking layers. Layer 1 (is the physical layer) is the lowest level and describes how it's physically possible to encode a sequence of 0s and 1s over a particular medium. Layer 2 (the link layer) assumes that you already have the physical layer sorted out and describes how you can reli... | [
"What allows the data to move to the correct point B? -- what prevents my desktop data from interfering with my phone's data?",
"Every request you make is made up of little packets of data. The router sends out a bunch of little packets and your computer pieces them all together. But how does the data know whic... | [
"Thank you. This answer is very thorough. In regards to level 2, we have 4-6 devices connected to WiFi most times. Say they are all on N networks at 2.4 GHz. What allows the data to move to the correct point B? -- what prevents my desktop data from interfering with my phone's data?",
"Besides Wikipedia, what's a ... |
[
"Assuming a virtually lossless fiber optic cable, is there an upper limit to the amount of light (intensity) it can carry? If so, is it dependent on diameter?"
] | [
false
] | I'm toying with the idea of installing fiber optic lighting in my living room to pipe sunlight from outside to illuminate the room during the day, and I started wondering about how many fibers I would need. This in turn made me ponder how much light I could fit through a single fiber, and how well that would work.... I... | [
"I decided to do a quick google search, and apparently there is a limit in distance at least for sending information based on the dispersion of the signal, which is a problem in all waveguides I believe.",
"http://en.wikipedia.org/wiki/Multimode_distortion",
"You are asking about something else, but I thought i... | [
"Indeed! I appreciate it. Have an upvote and an orangered."
] | [
"If it's actually lossless and not just virtually lossless, then there is no upper limit. Such a thing doesn't exist of course, so there is a damage threshold. For continuous-wave input into large-area (multimode fibers with diameters >100 micrometer) silicon fibers, you can go to tens of Watt without causing damag... |
[
"What is the relationship between ORP (Reduction Potential) and the concentration of CL in a saltwater pool? We are pool ops in need of guidance!"
] | [
false
] | I am a pool manager and operation at health club with three warm saltwater pools and a saltwater spa. The other pool ops and I are constantly struggling with the correlation between the ORP probe readings on our controllers in the pump room and the hand readings we get from using reagents to test water samples. Accordi... | [
"The explanation lies in electrochemistry. Free Chlorine in a pool is dissolved bimolecular chlorine gas that is produced by the redox reaction of hypochlorite ion with chloride ion (as in Bleach). This FCL is very oxidizing; it sanitizes the pool by oxidizing organic species (like bacteria) to chlorocarbon compoun... | [
"So, one further question. I'll be checking out the Nernst later today, but in the meantime, what about false readings when neutralizing free CL with sodium thiosulfate in salt water? Would the ORP probe continue to provide a reading that corresponds to high CL even after thiosulfate has been added because of its s... | [
"I wasn't quite sure about this effect, but I will guess (so don't take my word for it). I know that thiosulfate is a reducing agent that reacts with bimolecular chlorine gas to give chloride anion and either tetrathionate or sulfate anions. It may be that local levels of Cl2(g) close to the ORP probe are unaffecte... |
[
"Could one make a vaccine to train one's immune system to attack their own body?"
] | [
false
] | As opposed to markers of some virus or whatever. Have there been incidents of people getting an autoimmune disease from vaccination trials? (obligatory: this is unrelated to covid, though perhaps the soreness from the booster is encouraging this on my mind. Very pro-vaccine, I am just curious if such a thing is possib... | [
"The immune system has a built in mechanism that destroys cells that recognize self-antigen. This doesn't always work (see: autoimmune diseases), but most of the time it does.",
"In some conditions like Gullain-Barre Syndrome, something foreign (like a vaccine or a bacteria in undercooked turkey) can stimulate a ... | [
"Yes, in fact these are used to combat various forms of cancer.",
"References are so thick you'll have to sort through them yourself:",
"https://pubmed.ncbi.nlm.nih.gov/?term=cancer%20vaccine&filter=pubt.review"
] | [
"Feel like it's important to emphasize that GBS tends to be way worse with wild flu than with the vaccine"
] |
[
"How close did we estimate the gravity of the Moon and Mars before we sent probes there?"
] | [
false
] | When we got there, we could simply compare the weight of the probes there with their weights back on earth. But how accurately did we estimate their gravities before that physical evidence? | [
"Most mass estimates come from things orbiting that object. Mars has two moons, observe their distance and orbital period and you can get a very good estimate for their mass. Same for all the outer planets.",
"The Moon doesn't have any natural object orbiting it but its gravitational force on Earth is strong enou... | [
"You can't get the mass of a body from its orbit, only the mass of the body it's orbiting."
] | [
"You can't get the mass of a body from its orbit, only the mass of the body it's orbiting."
] |
[
"If helicopter propellors spin smoothly, why do they make percussive \"buh buh buh\" sounds instead of a more constant hum?"
] | [
false
] | null | [
"\"Rotor flap\" is the correct answer, but it's more complicated than that.",
"There are two main controls in a helicopter - cyclic pitch and collective pitch.",
"Cyclic pitch alters the blade's angle of attack depending on where the blade is in rotation. This is controlled by the joystick, and it's what contro... | [
"The sound is created from the previous blade creating a vortex in the air as it spins, then the next blade hits this vortex creating the \"buh\" sound.",
"The reason why it's not humming is because they blades aren't spinning fast enough."
] | [
"The tiniest bit I ever thought I knew about helicopters... just got put into perspective."
] |
[
"HIV mutation, why doesn't it mutate itself out of virulence?"
] | [
false
] | It is my understanding that retroviruses in general mutate very rapidly because they don't have the normal mechanisms for checking for errors in transcription (possibly wrong term, hope you get the point). What I would like to know is why if they mutate so quickly do they not mutate themselves into a form that is no lo... | [
"Actually, there are a number of strains that are less deadly. HIV-1 and HIV-2 are fairly different, with HIV-1 being far more deadly and more infections. Among HIV-2 infections, you can split them down into groups that are labelled, I think, A through P. Some of these are known for causing specific problems, while... | [
"Don't feel dumb, it's not common knowledge. In reality, most scientists don't even consider viruses alive. All that's really happening is a series of organized chemical reactions that result in more viruses. The only function a virus has is injecting genetic material into cell. There is literally nothing else tha... | [
"There's nothing stopping it from happening, but many viruses replicate by a few steps",
"So the idea of a virus becoming non-virulecent is not impossible, but once it mutated, it would never reproduce. The mutation would never become sustainable."
] |
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