title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
|---|---|---|---|---|---|
[
"What happens to nerve endings when we experience a burn of any kind? Does the nerve get such a sensory overload that it just shuts down instead of trying to process it all?"
] | [
false
] | null | [
"The nerves do no 'processing' themselves. When you apply a stimulus this strong nociceptors will fire rapidly inducing a sharp pain. If the heat source was sufficient to cause physical damage then inflammation will make the area very ",
"sensitive",
" to further stimulus, even non damaging stimulus. This is wh... | [
"In short, no. The nerve is firing like crazy after a burn. Your damaged skin is releasing signals that are received by the nerve endings. These signals inform you that you are in serious pain.",
"Now, let's get a bit more technical. There are different classes of nerve fibers for pain and touch sensation, as... | [
"You can overload the collator of some sensory information, the hippocampus, but the others have addressed the rest of this process well. Overload, in this case, would lead to blacking out, and just prior to that, you'd have blinding pain. Nothing happens to your eyes, per se, but there's a bottleneck at that par... |
[
"How are the triple(or more) parachutes commonly seen on capsules returning from space kept apart?"
] | [
false
] | Judging by the direction of force by the cord, shouldn't they be pulled together? | [
"There's a few things at work here. One is that the cables aren't all the same length, which will naturally give a lean to the parachute. Then there's the shape of the parachute, it's not completely symmetrical. There's also a lot of air pressure around the parachutes pushing them away."
] | [
"They also fire them out of cannons in three directions. They also \"vent\" the canopies to help.",
"Here is a paper on the ",
"Apollo system written by T. W. Knacke",
". Someone I got to spend a day with a few decades ago."
] | [
"Kind of like how you can use a sail to travel in directions other that directly with wind. "
] |
[
"Does Earth's atmosphere expand as a consequence of climate change?"
] | [
false
] | When climate change is discussed a increase in mean atmospheric temperature is often mentioned. As we know, gasses expand with increased temperature. Does this mean that the total volume of Earth's atmosphere also increases? | [
"Great question! Air expands as it warms, but ",
".",
"In particular, the troposphere, the lowest region where we live and where weather happens, is as you know warming. As a result, the height of the top of that layer, the tropopause, is rising over time.",
"Surprisingly, though, increased CO2 causes the u... | [
"While the atmosphere and ocean expand due to warming, the size of the atmosphere shouldn't change since the gravity gradient is static. As the atmosphere expands, more air molecules would have the necessary energy to escape. The transient case might have a larger volume but once the increase in temperature stops t... | [
"Thank you for the detailed answer, great stuff! "
] |
[
"Would a Tesla Coil work in a Vacuum?"
] | [
false
] | If not, why not? | [
"I see no reason why not. ",
"In fact, you can see it in action for yourself."
] | [
"If the electrical potential difference (ie Voltage) was great enough there would indeed be an electron flow. But since it's not hitting any particles of gas, no ionisation takes place and the flow emits no light."
] | [
"A Tesla coil should be able to operate in a vacuum. However, I don't believe you would be able to see the electric discharge that most people associate with a tesla coil. The electric arc you can generate from a tesla coil is the result of turning air turning into a plasma. In the absence of air there would be ... |
[
"The sun radiates about 1000 Watts/m^2 of light on the surface of the earth. How much does that compare to a single star at night?"
] | [
false
] | null | [
"The Sun's apparent magnitude is -26.7. The \"average\" star you can see in the night sky is something around apparent magnitude 4. (The brightest star is -1.5, faintest you can see ~5-6).",
"For every 5 magnitudes more negative, an object is 100 times brighter. So the Sun is -26.7 - (-1.5) = 25.2 magnitudes brig... | [
"Multiply the intensity of one star by the number of visible stars. Google tells me less than 10000, so still probly much less than 1 mW/m"
] | [
"What about the sum total of light produced by all of the stars in the night sky ignoring moonlight"
] |
[
"How do cellphone and bluetooth signals travel through walls??"
] | [
false
] | Ok so correct me if I'm wrong, but aren't both signals made up of electromagnetic waves, the same stuff as visible light just with more energy and smaller wavelength. So, if visible light cant travel through walls, why can bluetooth and cellphones?? Is it because of the increased energy?? I know that the photons (assuming cellphones and bluetooth rely on photon based transmission) aren't any 'smaller' so it's not like they would fit through subatomic gaps in the walls. What am I missing?? | [
"The default is for photons to go through matter. Absorption can be seen as the unusual event which occurs when the photon matches an energy gap available in the material it hits. Metals have lots of energy levels available in their sea of electrons, so they will absorb most photons; the cellulose and lignin in a w... | [
"It's all about the electrons in the material. Jiminuse gave a couple of good examples above. I'll try to elaborate a bit. There are a few processes that can happen:\n1) The photon passes through the material\n2) The photon is absorbed\n3) The photon is reflected\n4) The photon is scattered",
"1) is actually not ... | [
"Note, metals are highly reflective, and not highly absorptive because they have a sea of effectively free electrons that can respond near-instantaneously to the incident waves, especially at lower frequencies. ",
"The key worth reiterating is that radio waves have much longer wavelengths than visible light, and ... |
[
"Question about boiling water in a vacuum and oil extraction."
] | [
false
] | So when making beer, hops are boiled with the beer malt to extract the oils and acids which add the flavour. Secondary 'hopping' is later used to give a fresher, brighter hop flavour, as alot of the compounds in the hops are destroyed from the heat in the boiling process. The boiling is required, however, to initially extract enough of the hop compounds. Similarily, coffee is generally brewed to specific ground size/temperature/time to extract the optimum flavour, as too much heat makes the coffee bitter and acidic. Coffee can be brewed with cold water for an excellent cup of coffee, it just takes anywhere from 4-18 hours and specific ground/water exposure. If water will boil at a lower temperature when exposed to a vacuum, how does this effect the process in which these oils and flavour compounds are extracted. Is the temperature of the solution being used essential for effective extraction, or does the physical act of 'boiling' do the work. Because the molecules of water are 'vibrating' the same when boiling irregardless of temperature, I assume that you would be able to extract more oils without the negative effect of temperature. Or am I completely wrong, and the damaging effect would be the same? | [
"You would not end up with the same end result you'd get when boiling at sea level pressures, unknown if it'd be better or worse. ",
"The oils and other compounds have their own flashpoints, vapor pressure, and other characteristics. Each has their own rate of change with regards to how they respond to a change... | [
"Id never heard about pitch from trees, read a bit on it and its pretty interesting"
] | [
"Here's a neat, broad overview on some of the more commonly known chemicals found in trees: ",
"http://treedictionary.com/DICT2003/shigo/TREECHEM.html",
"EDIT: in addition to the common ones such a sugars and the wide variety of oils."
] |
[
"Why is the \"philia\" suffix being used increasingly by academics to denote sexual, or \"eros,\" love, when the Greek roots are clear in their respective differences of meaning?"
] | [
false
] | Does this mean that bibliophiles want to have sex with books, or audiophiles have orgasms listening to music? Doesn't the injudicious use of the suffix to denote sexual attraction in certain terms (paedophile, androphile, gynephile, et al.) lead to confusion and difficulty educating others? Shouldn't any "philia" that is defined as sexual in nature be renamed with the "-erotic" suffix, since the Greek roots are defined precisely? | [
"-erotic is already used, like in \"homoerotic\", \"autoerotic\" and probably a lot more words I can't think of right now.",
"-philia is way more common, but it doesn't mean the same thing in English that it does in Greek. It's acquired all of the connotations of \"like\" or \"love\" in English. That's why it can... | [
"\"Philia\", as I know it, is simply the fondness for something. I guess that can escalate all the way to the \"love\" of something, but I think it's defined pretty broadly in that sense.",
"Any time I've heard it used for sexual interests or proclivities, it would mean \"the love of\". I don't think it explicitl... | [
"Well that's a fair criticism, I suppose, but my intention was pretty much the opposite of pedantry, since the exact issue I raised I encountered in my own learning, which was why I brought it up and questioned it. ",
"Would you agree that unchecked semantic drift could lead to a more rapid erosion of understandi... |
[
"Suppose there actually is a multiverse, and we found a way to send information between parallel universes. Could that be used to violate Heisenberg's uncertainty theorem?"
] | [
false
] | null | [
"Quantum mechanics says nothing about the result of such an experiment. You can't just make up hypotheticals that violate basic principles and then ask what those basic principles say in such a situation. There's no reason that atom A in universe A and atom B in universe B would have anything to do with each other.... | [
"Oh sorry, I thought the bit about atom A and atom B was the explanation. But I can try to explain a bit more. ",
"First, the notion of parallel universes is little more than conjecture so to assign any particular rules to them is arbitrary. Second, if there is interaction between the universes, then it really is... | [
"Was it in using the many-worlds interpretation as a framework for the thought experiment?",
"Not at all; the MWI is consistent with modern quantum mechanics.",
"Or did I step outside the bounds of MWI itself?",
"This one.",
"First, I think you've misunderstood the MWI. The many-worlds are ",
" distinct u... |
[
"How do we know the actual wavelength of light originating from the cluster of galaxies that are receding away from us when all we observe is red shifted light because of expansion?"
] | [
false
] | null | [
"Every element has its own characteristic spectrum of light, so we can look for this fingerprint in the light we receive. Since hydrogen is by far the most abundant element, we expect the spectrum of hydrogen to feature prominently. However, the features of the hydrogen spectrum won't appear at the same wavelengths... | [
"For galaxies, you would generally see uncertainties on the order of a few km/s. This sounds like a lot, but is actually pretty accurate.",
"The most precise measurements I know of are those used to detect exoplanets. If you have a solar system, the star is not perfectly stationary at the center. Instead, it revo... | [
"How accurate is the estimate?"
] |
[
"How many gamma rays is the average person exposed to on Earth?"
] | [
false
] | null | [
"Lots. If you spend a lot of time in a building made of concrete, you're getting gammas from the small amount of potassium-40 in natural potassium. If you have an americium-241 smoke detector, you'll get gammas from that. ",
"Am alpha-decays into ",
"Np, but it doesn't always go directly to the ground state. So... | [
"Silly question: Has the average number of Gamma rays been calculated/estimated? It'd be a fun little fact to know."
] | [
"I decided to see if I could work out what \"lots\" meant, but I think I must of screwed up. What did I do wrong?",
"Here is my working:",
"Let's see if we can get an order of magnitude. According to ",
"https://xkcd.com/radiation/",
", the average background dose is 10 microsieverts. A Sievert is a dose of... |
[
"Are quarks and electrons really indivisible?"
] | [
false
] | I read somewhere that quarks and electrons are indivisible. How can we know that? As far as I know, the term "atom" means indivisible in greek, which shows we once thought the atom was indivisible as well. It's hard for me to understand how something can exist without being made of anything else, it just exists. | [
"The excitations in a spin liquid (not a state liquid) are not literally an electron split in pieces. Rather, the collective excitations of a system are quasiparticles which carry fractions of the electron's quantum numbers (charge, spin, and statistics). This kind of fractionalization has already been convincingly... | [
"It's hard for me to understand how something can exist without being made of anything else, it just exists.",
"Do you imagine that the sub-particles of electrons and quarks would also have sub-particles etc.? I find the idea of there being an infinite regression of sub-particles much harder to swallow."
] | [
"Is it just ",
" or is it - with our current understandings of physics - impossible? I always wondered, since the universe is supposedly infinite in size, why should there be a lower limit for size? Also, black holes (as far as I understand them) are basically a single point with all the mass in it, \"surrounded\... |
[
"Do other species, animals, etc. experience the placebo effect?"
] | [
false
] | [deleted] | [
"This is an interesting question. In humans, the placebo effect works because of the recipient's belief in the efficacy of the medication.",
"So, if it worked for any other animal, that would be proof that they were intelligent enough to understand what medication is, and had enough imagination to project what th... | [
"Probably",
"There is also an indirect placebo-like effect when humans judging the state of the animal know (or believe) some treatment happened: ",
"Discussion"
] | [
"There is a study showing that the placebo effect works in dogs to reduce seizures: ",
"https://www.ncbi.nlm.nih.gov/m/pubmed/19912522/",
"However, researchers think that it arises because dogs trust humans for medication. When an owner gives it something that’s not food, dogs take it expecting to get better, p... |
[
"Why does blue light penetrate water the furthest, but when you get to shorter wavelengths like UV it barely penetrates?"
] | [
false
] | null | [
"When you say blue light penetrates water the furthest, are you referring to the absorption spectrum of water, or the fact that large bodies of water appear blue? These two phenomena have different explanations.",
"Each compound has a characteristic absorption spectrum, which dictates its colour. Water tends to a... | [
"I'm not really concerned with the color but just depth of penetration. I was under the impression that blue light in low turbidity waters is able to penetrate water the furthest depth wise. I thought it was because shorter wavelengths are more energetic but are more easily absorbed. Blue light is the shortest w... | [
"Penetration is basically the inverse of \"interaction with matter\". The more it interacts, the less it will penetrate. Absorption is that interaction in this case, so as stated before, blue light doesn't get absorbed as much as UV or red light is, thus having a larger penetration depth.",
"Penetration depth doe... |
[
"Can pair annihilation occur in free space?"
] | [
false
] | I know that pair production cannot occur in free space, but can pair annihilation? If so, why? | [
"Both processes can happen in free space. Specifically, a particle anti-particle pair can annhilate producing two photons with the same total energy as the energy of the two particles, or two photons can annihilate creating another particle/antiparticle pair (the photon is its own antiparticle).",
"The event you ... | [
"/u/quantum-confinement",
" nailed it; but I'll be even briefer.",
"Yes, pair annihilation can occur in free space, and pair production can too. Either one is a ",
" interaction (two photons, one electron, one positron), and both directions are allowed. "
] | [
"Yes. When massive particles are already present, there is sufficient energy in any reference frame for the interaction to occur. With just a photon, there can be a reference frame in which it does not have enough energy to produce particles."
] |
[
"Which way should a car swerve to avoid flipping over? Should it speed up, slow down, or stay the same speed while doing so?"
] | [
false
] | I don't know how to describe this exactly, but say a person is driving a car and something hits it on one side in such a way that it starts tilting to the right (in a clockwise motion if viewed from behind). The driver has barely seconds to react before the car is flipped over. Which way should he swerve to avoid flipping over? Also, would speeding up or slowing down affect leveling the car out at all? | [
"I was taught to \"steer into the skid\", or, in other words, as you lose control you steer in the direction the car is heading. This works well for skids, though it can be counter intuitive. Rolls usually start as skids.",
"By pointing the front wheels in the direction of movement, they will roll instead of slid... | [
"Thanks! I should have been more specific with my question though; for the example scenario I gave, I was imagining the car beginning to roll because it ran into an object like a curb or something on one side, so it hit one wheel and immediately began the roll. Basically what made me think of the question was that... | [
"I'll take a stab at answering this.",
"Say the car is swerving left, and therefore will roll clockwise (when looking through the car from the rear). The driver should steer right, so as to counteract this roll (steering right will make the car try to lean left).",
"In terms of speeds, braking will cause the ca... |
[
"How do you calculate velocity in space?"
] | [
false
] | Do you use Earth or the Sun as a frame of reference? Is there some way to find out how fast they are moving through the universe? How does the speed of our solar system affect time? If you found a way to come to a stop (with respect to all of existence), would the traveler age faster than everyone else on earth? Would the earth appear to move away slower? Disclaimer: I am not really educated in any of this, barely have any knowledge of relativity, just curious. Edit: Would it matter which direction you started moving? For example: moving away from Earth in the direction of the expansion of the universe would increase your true(?) velocity, while moving toward the center would decrease it. | [
"You can use any reference frame you like, there is no absolute frame of motion in the Universe. If we measure the orbit of the planets, then the speed is in relation to the Sun - but if we measure the orbit of the moon, then the orbital speed is in relation to the Earth. The speed we measure Voyager travelling at... | [
"It is completely true that there's no absolute from of motion in the universe. And as far as current space travel is concerned, using the Earth or Sun as a reference is a good way to define velocity. However, I think that if we ever find a way to travel at velocities close to the speed of light, the CMB would be a... | [
"In fact, you're always sitting still in your own reference frame. It's everything else that's moving."
] |
[
"Ask Anything Wednesday - Biology, Chemistry, Neuroscience, Medicine, Psychology"
] | [
false
] | Welcome to our weekly feature, Ask Anything Wednesday - this week we are focusing on Do you have a question within these topics you weren't sure was worth submitting? Is something a bit too speculative for a typical post? No question is too big or small for AAW. In this thread you can ask any science-related question! Things like: "What would happen if...", "How will the future...", "If all the rules for 'X' were different...", "Why does my...". Please post your question as a top-level response to this, and our team of panellists will be here to answer and discuss your questions. The other topic areas will appear in future Ask Anything Wednesdays, so if you have other questions not covered by this weeks theme please either hold on to it until those topics come around, or go and post over in our sister subreddit , where every day is Ask Anything Wednesday! Off-theme questions in this post will be removed to try and keep the thread a manageable size for both our readers and panellists. Please only answer a posted question if you are an expert in the field. . In short, this is a moderated subreddit, and responses which do not meet our quality guidelines will be removed. Remember, peer reviewed sources are always appreciated, and anecdotes are absolutely not appropriate. In general if your answer begins with 'I think', or 'I've heard', then it's not suitable for . If you would like to become a member of the AskScience panel, . Past AskAnythingWednesday posts . Ask away! | [
"Can you please explain the differences in sex, gender, and how chromosomes fit into the picture. I’m curious about the lifestyle effects of each are driven by those factors. ie: Say someone is born with XXY. How is their life impacted by this if at all?"
] | [
"OK, so let's start at the beginning. Your genome is composed of 3 billion bases of DNA. Those 3 billion bases are found on 46 different strands of DNA. Each strand is called a chromosome. Hence, you have 46 chromosomes. There are 22 chromosomes that are what we call autosomes, they basically look exactly the same ... | [
"To my knowledge, the difference is mainly about chemical reactivity.",
"Nitrous oxide is pretty chemically unreactive under normal conditions, and its anesthetic effects are similar to other gases like xenon, carbon tetrachloride, cyclopropane, or even nitrogen under high pressure. You can read about what we kno... |
[
"If lobsters have the ability to naturally live indefinitely, why don't we have large millennium old lobsters running around?"
] | [
false
] | null | [
"Predation from humans and other top predators may play a role, as may competition from smaller lobsters. Being big doesn't necessarily make you better at catching food, and you have fewer places to hide. Plus there is disease and accidental death to slowly weed out the old ones.",
"There are records of lobster... | [
"Does anyone know if anyone has a captive lobster that they are trying to keep alive for as long as possible? If not this should happen. "
] | [
"http://www.int-res.com/articles/dao2007/79/d079p173.pdf",
"I had it wrong, it's actually the other way around. Healthy lobsters will avoid diseased lobsters (Caribbean spiny lobster ",
") even a week or more before they are infectious, at least with the virus PaV1. The juveniles also live solitary lives, which... |
[
"Why hasn't America switched to the SI metric system?"
] | [
false
] | null | [
"I'm not sure if this is a scientific question or even answer, but in my opinion it's social momentum. Think of all the people who have grown up using imperial units and how much of a fuss they would kick up if there was a change. I imagine the only way it will happen is by putting both units of everything and then... | [
"But all the other countries used different methods as well. They grew up with them as well. But then they switched. How come that almost every country switched except a few. And those are not some undeveloped countries. USA, UK, they're global players. They're a big part in today's globalized world."
] | [
"The UK does use metric everywhere except for miles really. I think it is partly also a social issue, maybe Americans are less willing to change. This really isn't a question for science though since all scientists use metric anyway."
] |
[
"Does Purcell's Relativistic Electromagnetism model contradict Maxwell's Equations in any way? Are they equally valid in a predictive sense?"
] | [
false
] | null | [
"I am not an expert on Purcell, but a bit of googling/wikipedia implicates to me that Purcell simply had a different way of explaining the same theory."
] | [
"They are the same, just a different derivation. ",
"It isn't a \"model\". That word has a very important definition to physicists. What he did was use his understanding of Special Relativity to explain things like magnetism. "
] | [
"It contradicts in that it is relativistic when Maxwell is not, but that is probably already assumed. ",
"The basic gist of Purcell's explanation is that electrostatic force is fundamental, and magnetism is explained using relativity. It seems magnetism arises as a natural side effect of the speed of light rema... |
[
"Physics question: physics and scale (Not exactly sure how to formulate this question)"
] | [
false
] | I was wondering, if Newtonian Physics become inapplicable at small scales (quantum physics), what happens when we go the other direction and increase the scale proportionately? In other words, if we scale up large enough, do Newtonian physics become inapplicable? | [
"You mean if we consider stars and galaxies instead of apples falling? Newton's laws are good on the galactic scale for most things, but General Relativity is the true theory at larger scales."
] | [
"There are two possibilities that \"GR breaks down\":",
"Dark Matter problem, as cookie mentioned. That would lead us to MOND theories, which are very unlikely to be true.",
"Dark Energy problem, which is at even bigger scales - like size of the universe scales. Basically, we don't know why the vacuum energy we... | [
"Ohhh...good question. Currently, most scientists would say no. However, there is some very wacky and not well-understood stuff happening on very large scales. For example, on the scale of galaxies, the stars and solar systems do not have the proper angular velocities. To account for this we have created a conc... |
[
"What's determines the temperature of a star?"
] | [
false
] | [deleted] | [
"This is really a big issue and there's a whole field dedicated to \"stellar evolution\" and all its complexities!",
"Stars can change their temperatures throughout their life. Our sun is a yellow-white star, but it will eventually expand and turn into a cool red giant, before puffing off its outer layers and set... | [
"Stars don't accrete much mass after they have formed, the mass of a star is set by the so called Initial Mass Function, basically how much gas is around when it forms.",
"The reason blue stars \"have formed recently\" is that there aren't any blue stars around, that haven't formed recently, because they have a v... | [
"Thank you very much for your response.",
"Another question: You say that blue stars have formed recently. Now wouldn't you expect that new stars are smaller?"
] |
[
"Can anyone explain this phenomenon?"
] | [
false
] | [deleted] | [
"Ever seen one of ",
"these",
"?",
"The ",
"glow discharge",
" will follow your finger across the surface of the plasma ball because your finger is acting like an antenna for the AC frequency in the discharge. (more or less)",
"The fluorescent lights work in the same way, but apparently they didn't full... | [
"Shaking it could have helped, actually. There's a tiny drop of mercury in the tube that needs to become mercury vapor to sustain the arc. Shaking it could either distribute the liquid mercury more evenly, or distribute the heavier-than-air mercury vapor more evenly, especially if these tubes had been stored on end... | [
"I'll take a stab at this. Fluorescent bulbs usually act as a negative resistive device, which means the voltage across the terminals decreases as more current flows through them. This is because more current means more power, which means more electrons being ripped off from gas molecules to form a plasma, which me... |
[
"Are Dogs and Cats closely related in genetics?"
] | [
false
] | null | [
"Timetree.org",
" is a search engine to find the evolutionary split between two taxa / species - and the example on their start page is in fact \"cats and dogs\". :-)",
"See here,",
" they seem to have had a common ancestor some 50-60 million years ago.",
"For comparison, cats and humans split ~100 million ... | [
"According to ",
"Wikipedia",
", the divide between Caniforms (dog-like animals) and Feliforms (cat-like animals) occurred very early on in the evolution of the order Carnivora, potentially as early as 42 million years ago.",
"Considering how far back that is, it's probably safe to say that dogs and cars are ... | [
"I was just looking that up! Wikipedia cites ",
"this article from 2006 (PDF)",
", which places the split \"around\" 42 million years ago. But that doesn't seem to be considered authoritative, because Google points me to ",
"this review from 2009",
" that still puts it anywhere from 40 Ma to ~66 Ma.",
"I'... |
[
"Is any number over infinity considered real?"
] | [
false
] | null | [
"\"Dividing by infinity\" is meaningless if you're dealing with real numbers. You can define the ",
"extended real numbers",
", which is just the set containing all real numbers, positive infinity, and negative infinity.",
"Then you can extend the typical arithmetic operations to include infinity. For example... | [
"Just a follow up. Would that mean that infinity over infinity would be 1? "
] | [
"You can see a list of the conventionally defined operations ",
"here",
"."
] |
[
"Can I be tasered while I am touching a lighting rod?"
] | [
false
] | The lighting rod I just mean my body is grounded. | [
"Tasers fire two electrodes that stick into you. The current flows in a closed circuit: taser -> electrode -> you -> other electrode -> taser. Current flow in that circuit is not affected by touching a grounded object.",
"EDIT: What would probably work to some extent is wrapping your entire body in aluminum fo... | [
"They care very much, because if there is net current from the taser to ground, the taser will accumulate a voltage.",
"Back of the envelope: If a taser fired 2 mA average for 10 seconds, that would be a net charge of 20 mC. Modeling the taser as a 5 cm diameter sphere (the spherical taser approximation), its ca... | [
"Removing electrons from an object gives it a net amount of electric charge. That charge then creates an electric field from the object, and an electric field creates a voltage."
] |
[
"Can you break or bend the rules of the \"Fire Triangle\"?"
] | [
false
] | In school, we were taught about the Fire Triangle; the three requirements for fire, those being fuel, heat, and oxygen. Being that this was middle school (I think) I assume this was a dumbed down or simplistic version. What are some ways these rules can be subverted? Is it possible to replace oxygen with another gas, or perhaps start a fire without heat? | [
"To varying degrees, yes!",
"As was noted in another thread a few days ago, anything combusted by oxygen will still react with fluorine (and the original fuel will as well) in what is essentially a fire. Such environments are... uncommon, however. ",
"Heat is an inescapable requirement, but the amount required ... | [
"I wouldn’t characterize the Fire Triangle as dumbed down or simplistic. I would characterize it as practical and everyday. What you’re asking for are interesting yet unlikely “edge cases” few people will ever see outside of a chemistry lab."
] | [
"anything above absolute zero",
"Is going to give you difficulty, as all reactions require some enthalpy (heat) to get started. Depends on your oxidizer and your reducer.",
"The benefit here is that burning also produces heat, so it's self sustaining "
] |
[
"Can homogeneous isotropic turbulent eddies and vortex sheets during the formation of the universe, say when the universe was a 'continuum' before all the expansion...etc, be used to explain why the current state of the universe contains galactic clusters, superclusters, filaments and voids?"
] | [
false
] | Ok, Fluids Guy here: Does pressure and especially viscosity exist in any meaningful way at the scale of the universe? I mean clearly the universe is not a continuum anymore, but was it ever if it has always been infinite? Does the Reynolds number (ratio of inertial to viscous forces) mean anything on the scales of the early universe? What was the 'viscosity' of matter? Are there even estimates for what types of 'viscous' forces there are at such immense pressures and temperatures? Is there any force on a galactic scale in the universe which plays the role of 'viscous' dissipation or drag, because gravity is completely conservative...?? In the absence of such a viscous force, could the univsere be 'suffering' from the 2-D turbulence 'inverse energy' cascade? Hence, unbounded vortex (galactic) growth.. i.e. the universe is accellerating in it's expansion because energy feeds upwards? It's a huge conservative field... except for the role black holes play? I was speaking to a physicist friend recently. As I recall, he says that the Reynolds number of the early universe was quite low, so that turbulence was not possible until things cooled off and the viscosity declined sufficiently. I suppose he would say that the lumpiness in the current mass distribution is due to quantum fluctuations at the Big Bang. Any other theories? Thoughts? | [
"The people who study this stuff say that gravity alone is sufficient to explain the current structures in the universe."
] | [
"Damn, good questions. I can say that simulations have shown that gravity, itself, is able to create the filamentous macro structures observed in the universe.",
"Even with a conservative force such as gravity, there is still some sort of dissipation---when galaxies \"collide,\" momentum is transferred between bo... | [
"Is that where Dark Matter comes in?"
] |
[
"It this is true or just part ? (show flash)"
] | [
false
] | null | [
"Anything you see on Arrow or Flash to do with science, medicine or technology is going to be pretty much 100% made up.",
"For the mirror to do what they're proposing, it would have to have been kept in complete darkness before and after the lightning flashes, or the images would have been overexposed. If you hav... | [
"No, because as soon as you exposed the photosensitive surface to light it would ruin any potential picture. Mirrors spend a lot of time out of the dark, that's kind of how they work."
] | [
"No, because as soon as you exposed the photosensitive surface to light it would ruin any potential picture. Mirrors spend a lot of time out of the dark, that's kind of how they work."
] |
[
"What is the relationship between partially hydrogenated oils and trans fats?"
] | [
false
] | null | [
"Cell membranes are composed of various types of oils. This composition varies with temperature, as the cell adds or removes particular oils. The aim of that modulation is to keep the fluidity of the membrane at an ideal point. When the membrane gets too solid, the cell can add in these poorly-packing cis fats to i... | [
"\"Partially hydrogenated oils\" include trans fats and cis fats, which are both types of unsaturated fat.",
"Both contain a point, or points, at which hydrogen doesn't saturate the carbon skeleton; at these points, cis bonds introduce a kink in the line of the fat, whereas trans bonds maintain a linear shape. As... | [
"What do you mean by \"places they shouldn't be?\" What is it exactly that trans fats are doing that they have such a reputation for being unhealthy?"
] |
[
"How do Lagrange points L4 and L5 work? Are they always at a 60° between two bodies?"
] | [
false
] | L1, L2, and L3 are all pretty easy to imagine, with addition and negation of gravitational forces and all that, but how exactly to L4 and L5 work, and what makes them exist at the end of an equilateral triangle? | [
"Lagrange points come from the restricted circular 3-body problem (hereafter 'RC3BP'; two massive bodies with one massless 'test particle', restricted -> 2-dimensional, circular -> the orbits of the massive bodies around each other are circular). The assumptions of this problem are never fully satisfied in a real s... | [
"I hope you don't mind if I throw in a bonus question too. How would a rocket fly out to say earth sun L4? Does it first need to go into earth orbit and somehow get stuck in L4? Or can you just fly straight there?"
] | [
"Going to Earth-Sun L4 or L5 requires ",
" fuel then going into LEO. To get the Earth-Sun L4/L5, you need to effectively escape the Earth's sphere of influence. Escape trajectories require ~1.4x more delta-V (aka fuel) than circular orbits."
] |
[
"What would you see/feel as the earth collided with a Jupiter sized gas planet?"
] | [
false
] | null | [
"I like this question... I'll take a stab based on what I know, but I think an astronomer would still be able to win the day (disclaimer: I am not an astronomer; I'm actually an engineer).",
"I guess the first question is the trajectory these planets are taking: the most likely path (in which a collision is assur... | [
"All kinds of crazy shit",
"I like this science."
] | [
"Question: Since the Earth (and everything on it) would be falling into Jupiter at an equal speed, wouldn't you stay more or less on the Earth's surface? At least until you actually hit the planet and you had to take all sorts of friction/drag/air resistance into account."
] |
[
"Has an experiment or apparatus ever been used to convert energy into matter?"
] | [
false
] | null | [
"Particle Accelerators routinely do this. They take energy and make matter (particles) from it."
] | [
"To be clear, I was under the impression that they used the energy to accelerate existing matter and then impact it, causing destabilization of the high order particles allowing us to detect the lower order particles. Is that the case, or does the impact ultimately yield a mass gain at the loss of energy invested?... | [
"Well... here is an ",
"interesting article",
" I just found where they actually made an electron and positron from photons."
] |
[
"Why are humans not capable of the net synthesis of glucose from acetyl-CoA?"
] | [
false
] | I understand that other organisms use the glyoxylate cycle to generate large amounts oxaloacetate from acetyl-CoA, which can then move up the pathway to gluconeogenesis. But why is this not possible through the citric acid cycle? What mechanism in the citric acid cycle prevents the net synthesis of oxaloacetate? | [
"In the TCA cycle, carbons are lost in the form of CO2 in the conversion of isocitrate to a-ketoglutarate, and again in the conversion of a-ketoglutarate to succinyl CoA. The glyoxylate cycle bypasses these two steps and converts isocitrate to succinate and glyoxylate. The succinate can continue to participate in... | [
"Yes. Humans (and I think all vertebrates?) do not have the enzyme isocitrate lyase, which would allow isocitrate to bypass the steps I mentioned above."
] | [
"Ah. Okay.\nSo the carbons that would otherwise net oxaloacetate are lost in CO2, yes?"
] |
[
"How high a resolution camera would be required to be able to digitally zoom in a view individual atoms?"
] | [
false
] | ...and if it is possible, how long do you think it will be until we have such a camera? | [
"Optical (light-based) cameras will never be able to see individual atoms. Atoms are smaller than the wavelength of visible light, so it cannot be used to see them. It simply cannot provide the resolution necessary. You might be able to use gamma rays because they have a much much smaller wavelength, but you wou... | [
"http://www.youtube.com/watch?v=XEZtw1yt8Kc",
"This might help."
] | [
"The problem with that is that the pixels themselves are much much larger than atoms. We have special methods of imaging atoms in which we bounce electrons off of them and interpret the image from the returning electrons, called an electron microscope. I am no expert in the field of digital cameras but I am a physi... |
[
"What does a carbon notch in a FLIR do?"
] | [
false
] | The BriteStar Block 2, the FLIR found on the UH-1Y, has a detector element that sees Mid-IR energy in the 3.6-4.2 & 4.6-5.0 micron ranges. The 4.2-4.6 micron range has been filtered out, and is referred to as the carbon notch. Can someone please explain what the carbon notch is? | [
"Carbon dioxide absorbs infrared radiation in the 4.2-4.6 micron range",
", this means it also emits in the 4.2-4.6 micron range.",
"Carbon dioxide is present in our atmosphere.",
"To effectively see through the atmosphere you need to filter out the spurious emission and absorption due to the carbon dioxide. ... | [
"So basically, if it wasn't filtered out, the carbon would act like a wall, preventing the IR energy from reaching the detector?"
] | [
"No- it only absorbs/emits in that specific range. But CO2 is everywhere and sometimes you don't want to see it. FLIR typically only indicates the total infrared of all wavelengths observed. CO2 could obscure the image."
] |
[
"What kind of carbon do people use when a chemical formula has Carbon in it?"
] | [
false
] | null | [
"What do you mean by \"kind\"? Do you mean isotope?"
] | [
"No not like isotope like graphite coal diamonds Co2 or is there like a carbon gas or carbon powder ?"
] | [
"Carbon is the atom itself, graphite, coal or diamond are just ways those carbon atoms can be arranged. In a chemical formula like CH4 (methane) for example you just say that the carbon atome is stuck to 4 hydrogen atoms. It is not in graphite or diamond form, it is just in CH4 form."
] |
[
"We have iron in our blood, how strong a magnet would we need before we could pick up a mouse? A person?"
] | [
false
] | null | [
"Please post calculation requests to ",
"/r/estimation",
" or ",
"/r/theydidthemath"
] | [
"Crosspost or delete this one?"
] | [
"Already removed"
] |
[
"If we didn't have observational data, would there be any reason to think that the speed of light is constant in all reference frames?"
] | [
false
] | Perhaps another way of putting it is, is there some underlying principal that explains why it is that the speed of light is constant, rather than time or space or something else? | [
"all science is based on ",
" kind of observational data. If you mean \"aside from watching light move in different frames, how else do we see the effects of relativity?\" Well we would see that there is a fundamental limit on the speed of any kind of information in our universe. Anything that is massless must tr... | [
"Yes, you could make that claim from examining Maxwell's equations."
] | [
"The Michelson-Morley experiment was designed to gather data on the luminiferous aether. The surprise was that the results seemed to be that there was no luminiferous aether. Maxwell's equations combined all forms of electromagnetic radiation into electromagnetic waves with the catch that light had to always be tra... |
[
"Why do different types of ticks carry different diseases and coinfections while populating the same area and eating the same bloodmeals? E.G. red meat allergy being limited to lone star ticks and dog ticks not carrying Lyme?"
] | [
false
] | Why is it you are not likely to contract Lyme disease from a dog tick, but, you are from a deer tick? They both carry infectious disease, they both feed in the same territory, and they are both bloodmeal parasites. The same goes with the famous red meat allergy you can contract with a lone star tick. How does the type of tick vary which also varies your risk to tick borne illnesses? | [
"The animal has to be a vector for the disease as well. A bacteria or virus will be evolutionarily adapted to being in a specific host body than another. So even if they fed on the same blood, a specific bacteria/virus/parasite might not be able to propagate in certain hosts. It's the reason why not every disease a... | [
"different ticks have different preferred hosts. immature deer ticks often feed on mice, which carry lyme disease, and the adults very much prefer white-tailed deer and other larger mammals. This allows the lyme disease to transfer to the larger mammal. Dog ticks are more generalist and live in a larger range, but ... | [
"Since Dog ticks are more generalized and feed on the same mice presumably, wouldn't that make them eligible to pick up the same vector as deer ticks?"
] |
[
"Is it possible for organic life to exist that isn't carbon-based?"
] | [
false
] | null | [
"No, by definition. Organic materials must contain carbon.",
"As for carbon based life, it's possible in theory. Silicon is the most likely contender since it can form similar molecules to carbon. "
] | [
"It's reasonably likely that the study that found that was mistaken. ",
"http://www.nature.com/news/2011/110809/full/news.2011.469.html"
] | [
"Not only was that study poorly executed and never replicated, but it was never hypothesized that the bacteria were not carbon based - only that arsenic was substituting for phosphorus in nucleic acids."
] |
[
"Why are animal clones so prone to early deaths?"
] | [
false
] | Every time I here about clones they always seem to be much more susceptible to diseases and genetic disorders. If they are genetically the same to there counterpart why do they die early so much more often? | [
"Our genes have ",
"telomeres",
" on the end of them. Telomeres are repetitive portions of genes that protect the gene from deterioration. Every time a gene replicates, a little bit of the telomere is cleaved off. Eventually, the telomeres run out, and when a cell replicates a bit of useful gene is cleaved. Thi... | [
"I need to correct a few errors in this answer seeing how I'm doing postdoctoral research on telomerase.",
"Our genes do not have telomeres on the end, our chromosomes do.",
"A little of bit of the telomere is not cleaved off. ",
"During chromosomal replication you unwind double stranded DNA, which results in... | [
"So if you clone a fetus, you wouldn't have that problem?"
] |
[
"will plasma moving through a coil produce electricity?"
] | [
false
] | pretty much the title, say i have a hot fast moving charged plasma and i pass it through a coil, will this produce electricity. my instincts say yes, but i'd like some confirmation from someone with a bit more of a background physics. | [
"Where exactly do you expect electricity?",
"If the plasma has a net charge (quite unusual) and moves through the coil you have a current flow. If this current flow changes with time you can get induction, although a coil around the current flow is not a good geometry to use it."
] | [
"It won't work for a simple coil, but a slightly more complicated device will do that. If you move a plasma (or any conducting fluid) through a tube containing a magnetic field that's perpendicular to the flow, you'll create a voltage perpendicular to both field and flow. If you put electrodes on the side walls o... | [
"It will produce magnetic field if you somehow manage to move the same type of plasma charge particle in 1 direction .",
"You question is wrong from the basic . What you mean is electric current ? \n What you asking is basically \" if I drink Pepsi from a straw will it produce coca cola ?\""
] |
[
"Why do vegetarians get sick when they eat meat?"
] | [
false
] | I recently had a vegetarian friend eat chicken and get ill enough to puke. I was wondering why vegetarians gets sick when they eat meat. Also was wondering if someone who didn't eat meat in their first 15 years of life would be able to. | [
"I've seen several recent studies which show how different intestinal flora can be between individuals, and how differences in flora can lead to correlations with disease, behavior, and other vectors.",
"A vegan or vegetarian diet substantially alters the human colonic faecal microbiota",
"Commensal flora and t... | [
"Nausea and vomiting were likely psychosomatic in the case you described. I'd bet your friend didn't get sick until after they were told they ate meat. If you tell someone - anyone, not specific to vegetarians - that they ate something disgusting, there's a good chance they'll start feeling nauseated. If they dw... | [
"I was a vegetarian a few years back, for nearly a year. Decided to start eating meat again; the chicken went down fine. I also know someone who was a vegetarian for 10+ years, decided one day to eat a big ol' steak and felt perfectly fine afterward. So just as extra insight, in our experiences, there was no ill-ef... |
[
"Can two moons of a planet, over the long term, share the same orbit height/apogee/perigee but with different angle, without colliding?"
] | [
false
] | E.g. two moons, both in a circular 300,000 km high orbit around their planet, but one is equatorial and the other polar (or another angle, but not equatorial). Assuming we ignore how such an orbit came to exist, can it remain stable over the long term? By that I imply that the orbits actively keep each other form being on a collision course, using similar mechanics to orbital resonance. | [
"https://en.wikipedia.org/wiki/Co-orbital_configuration",
" may or may not be helpful. he ",
"Saturnian",
" moons ",
"Janus",
") and ",
"Epimetheus",
") and probably the most famous examples. However, I don't think they exactly share an apogee or perigee (which would technically be an apoapsis and per... | [
"No. If they are not on the same plane then the system would be unstable due to the Kozai mechanism (although as a side point a system could not evolve to this configuration anyway). One of the bodies (the lighter of the two) would be excited to a higher eccentricity (also likely its inclination with respect to the... | [
"They also have the same orbital plane. I don't see how such a setup would be possible with different orbital planes."
] |
[
"Why does thermodynamic data differ between sources so much?"
] | [
false
] | null | [
"As these quantities are experimentally determined, it's going to vary on the source the data is from, but after some digging, BaO's discrepancy has a neat history:",
"-556 kJ/mol - L. Brewer, Chern Revs. 52, 13 (1953).",
"-590 kJ/mol - G. C Fitzgibbon et al. J. Chem. Thermodynamics, 577 (1973).",
"-548 kJ/mo... | [
"Great answer! Living up to your username"
] | [
"What is the feeling towards enthalpy of formation from computational sources (quantum chemistry)?"
] |
[
"Can the flu virus from previous years help bolster your immune system against this year's strain despite the fact that it's a mutation of the same virus?"
] | [
false
] | A few years ago I got the flu for the first time, and I was bedridden and vomiting for about five days straight. This past weekend I got what felt like the flu, with the congestion and body aches/headaches, but I'm basically over it now and it seems tame compared to my previous bout with the flu. My utter lack of diagnostic skills notwithstanding, is there any way previous flu viruses help your immune system recognize the current mutation, even though it's not technically the same virus? I mean it's still "the flu", right? | [
"There is a selection process which happens when different flu strains make the leap from animals to humans. The strains which encounter antibodies capable of recognising them are unable to establish themselves in the human population and do not spread very well. So, each new strain of flu that arises should not be... | [
"There are lots of different strains of influenza, and these can range from being ineffective at causing disease, through mild symptoms, to the more severe symptoms. This is probably the major reason you had two different experiences.",
"However, it can also be explained by how influenza virus mutates. Influenza ... | [
"Influenza won't cause you to vomit. You likely didn't have influenza. In both of these cases, did you have a doctor verified case of flu? I would put my life savings on the bet that you didn't have the same virus in both these instances. I'd go double or nothing that neither instance was actually influenza. ",
"... |
[
"In series circuit how can the current be the same on every consumer if each of them have different resistance?"
] | [
false
] | Not really very fun question, but, hell, I want an answer. | [
"From all my EE college professors: Think of current like water flowing through a series of connected pipes. Regardless of how wide or narrow the individual pipes may be, the same amount of water will flow through all pipes.",
"I hope this helps your understanding."
] | [
"If the devices behave according to Ohm's Law, then each of them has a different voltage (V = IR). The sum of the individual voltages will equal the total voltage applied."
] | [
"Think of it like a series of liquid tubes connected together. You have one fat one connected to a super skinny one, and then a moderately sized one. Now try to force water through them.",
"What you will find is that the flow rate of water through each tube is the same, but the pressure in each is different.",
... |
[
"Breathe Nitrogen rather than Oxygen?"
] | [
false
] | Before I start, I have a very fundamental understanding of all sciences, only taking 101 and other introductory classes in college. So understand I'm aware this may be a ridiculous question, but I'm curious. I may also get some basic assumptions wrong, I apologize if this frustrates you like a simple misspelling would me. Okay, so humans and other carbon based lifeforms need Oxygen to breathe. As far as my understanding goes, the atmosphere is something around 70% nitrogen. Why is it that these life forms don't use Nitrogen as the primary form of "air"? OR, if that question is really stupid and obvious, is it possible for a form of evolution to occur sometime in the far future where we would depend more on Nitrogen (or other "air" source) rather than a disappearing oxygen? (Is oxygen even really disappearing?) | [
"Oxygen exists in the atmosphere as O2, but it is fairly reactive and can be incorporated into reactions easily. Iron rust is an example of how reactive oxygen is. ",
"Free O2",
" didn't exist in the atmosphere until photosynthetic organisms evolved, of which it is a byproduct. The organisms that first evolved ... | [
"It's not really a ridiculous question, your question actually has a good idea behind it. For a compound to be useful in our metabolism in the same way that oxygen is, it has to be able to readily accept electrons from an outside source. Oxygen atoms, being very electronegative, is good at accepting electrons fro... | [
"Since nitrogen is composed of nitrogen, and carbon dioxide is carbon and oxygen, yes, it is impossible for nitrogen to converted to carbon dioxide."
] |
[
"Could someone explain Quantum Computing to me?"
] | [
false
] | I'm trying to find more information about this, but everything seems overly complicated. Could someone explain the difference between traditional computing vs quantum computing? and what are the real world benefits of using one instead of the other? Thanks :) | [
"everything seems overly complicated.",
"It seems overly complicated, because everybody uses misleading analogies which fail to capture important elements, and then someone corrects them with a different misleading analogy..., and so forth.",
"The inherent difference is that classical computing is well describe... | [
"With quantum computing, for every qubit you add, you increase the number of concurrent threads by a factor of two. Using a multicore processor, you'd have to increase the number of cores by a factor of two.",
"Basically with quantum computing, there's a pretty big hump to begin with, but then the number of simul... | [
"The main issue is that quantum computing barely exists in reality yet. An example of the state of the art is a ",
"system with 14 qubits",
" which \"barely cleared the benchmark for fidelity.\" More robust systems of this kind have 8 qubits. A big issue for such systems is ",
"decoherence",
", which des... |
[
"How does the Peltier effect work?"
] | [
false
] | So i keep finding really general science answers of WHAT it is. But Im looking for a step by step of what is happening and why to full comprehend how heat or cold is being turned into eletricity | [
"Essentially the same way as the photoelectric effect.",
"Metals all have a particular electron band energy. This means that when you put two metals in contact ",
"they develop a voltage",
". That's the same thing that causes galvanic corrosion; the metals can react chemically to gain/lose electrons that ha... | [
"You're thinking specific heat. Electron make a negligible contribution to the specific heat of metals, but they are the dominant way through which heat is transported. An electrical current is a heat current."
] | [
"In metals the electrons are the major contributors to heat conduction, not phonons."
] |
[
"Are there any examples of two separate species of animals, or animals and plants, working towards a common goal, as a whole or in individual cases?"
] | [
false
] | null | [
"The biological term is symbiosis. It is when two species form a sort of relationship to the benefit of both. It could be something like the case of the tick-eating oxpecker (that little bird often seen on a rhinos and other large animals), or the nitrogen fixing bacteria in the roots of legumes. Symbiosis is commo... | [
"I don't know if I'm aloud to ask but I think this question don't deserve a post of it's own: Do animals of different species build physical structures (like bridges or holes) togheter? Has it been ever documented? "
] | [
"Yes that has been observed in nature also. For example, bioluminescent bacteria lives in the light organ of bobtail squid which the squid feeds and in return, it emits light to hide the squid from predators.\n",
"https://en.wikipedia.org/wiki/Bobtail_squid",
"Or are you talking about two organisms \"building a... |
[
"How did viral DNA become part of the human genome?"
] | [
false
] | There are some answers discussing how it was detected, or what they do, but none touch the topic of how viruses become part of our DNA. Specifically by what mechanism can anything external get integrated in anyone else dna? | [
"The life cycle of a virus goes as follows. A virus attaches to their specific host, then inject their genetic material into the host. The host then gets \"fooled\" into reading this material and making more and more viruses. Once there's so many viruses that the host can no longer perform the function to keep itse... | [
"Viruses are essentially little balls filled with genetic information and a couple of proteins that act like machines to help the viral genetic information get copied inside the cell. This involves taking the viral genome, converting it into a usable form, sticking it inside host cell ribosomes (protein making mach... | [
"In theory each generation would be an exact copy of its \"parent\" but mistakes can and do happen in the copying process so there can be slight differences in the next generation. Thats how the virus evolves. If these random errors in the copy end up making the new virus more successful there will me more of the v... |
[
"Why is the reflection of a projector green?"
] | [
false
] | [deleted] | [
"Most projector screens have a coating of small reflective crystals of different sizes and shapes to increase the brightness at different viewing angles. (This differs from a \"retro-reflector\" where they try to return as much light as possible in a narrow cone back to the source.) ",
"The green could be coming ... | [
"Most projector screens have a coating of small reflective crystals of different sizes and shapes to increase the brightness at different viewing angles. (This differs from a \"retro-reflector\" where they try to return as much light as possible in a narrow cone back to the source.) ",
"The green could be coming ... | [
"It would be interesting to see if the effect disappears when the projection surface is a matte white material (low specularity). Also, how does the green patch appear through polarized lenses (3D glasses). Of course, you don't know if the polarization is linear or twisting..."
] |
[
"Would a perfect ball rolling on a perfect plane in a non-vacuum environment make a sound?"
] | [
false
] | [deleted] | [
"This crossed my mind also, but I didn't want to put it in there for fear of people chiding me on semantics. But I agree, without friction, the ball wouldn't \"roll\" but slide, and would only rotate if given a rotational spin independent of the surface friction. ",
"Like a bowling ball that both slides and rolls... | [
"If there is a complete lack of friction can it still be said that the ball is rolling? Or is it just sliding at that point?"
] | [
"If the ball is rolling at first, it continues to roll because of angular momentum conservation, i think"
] |
[
"Why is the circumference of a circle the derivative of its area?"
] | [
false
] | area = pi r circumference = 2pi r Is there a real reason as to why this is, or is it just a quirk of geometry? | [
"The derivative is the rate of change. If you think about it, going from a circle of radius r to radius r+h (where h is very small), the area will increase by approximately one circumference (2 pi r) times a thickness h. As h->0, this becomes simply 2 pi r, the circumference. That is a visual way of looking at it, ... | [
"It's easier to see this once if you realize that the derivative of area with respect to radius (dA/dr) is actually dA = 2πrdr, which, it's easy to see, is indeed the infinitesimal area added when you increase the radius by an amount dr."
] | [
"If the \"radius\" of the square is r = s/2, then we have A = 4r",
" and P = 8r. The problem for ",
" shapes is, what is the \"radius\"?"
] |
[
"Did first generation stars have hydrogen planets?"
] | [
false
] | [deleted] | [
"We don't know for certain, as no first generation stars have been observed yet, as far as we know. If planets did form around some of those stars, they would be gas giants without the solid core that Jupiter is believed to have."
] | [
"Yup, it definitely would.",
"Jupiter is a Jupiter-sized ball of hydrogen, its about 90/10 hydrogen/helium. Most of the gas giants are large balls of hydrogen that got large enough that the hydrogen could no longer exceed the escape velocity and get blown off."
] | [
"Would a jupiter-sized ball of hydrogen have sufficient mass to prevent hydrogen from escaping its gravity?",
"That's basically Jupiter.",
"From wiki: ",
"The interior contains denser materials such that the distribution is roughly 71% hydrogen, 24% helium and 5% other elements by mass.",
"As far as I know,... |
[
"Do general anesthetics target a specific brain region or neuronal circuit?"
] | [
false
] | I understand that general anesthetics in most cases either increase GABAA activity or block NMDA channels (in the case of ketamine). But I can’t find an article that talks about where they target in the CNS. Obviously, exciting inhibitory neurons in different areas leads to different effects. Do general anesthetics target specific circuits or regions, or do they affect the brain globally? In that case how do they have selective functions (ie not messing with your vitals). Please correct me, as I’m more of a cog psych person than bio. | [
"I don't think there's much room for selectivity, we should be talking about the ",
" of CNS depression.",
"Talking about general anesthetics used to be easy, because you were just supposed to say that their mechanism of action was unknown. Nowadays, however, it's pretty much agreed upon where they act:",
"So... | [
"This is a bit of a tangent, but might be of interest anyways. Dexmedetomidine induces sleep, but is not used as a general anaesthetic in humans. It is used for procedural sedation for non painful procedures and as an ICU sedative. The mechanism of action is rather different from the other medications used. It is a... | [
"Thanks for your response, and I understand that degree is more relevant than selectivity; but it seems the two go hand in hand. So going back to my question do we know why it targets those certain structures before others? Why, if you administer a specific amount that it will depress the cortex and subcortex, but ... |
[
"Are there viruses that infect underwater/marine ecosystems?"
] | [
false
] | Are there viruses that infect underwater/marine ecosystems in the same way that COVID-19 (and other virus outbreaks) have infected aboveground ecosystems? If so, can we draw any conclusions about the transmissibility of viruses through the medium of water vs. the medium of air? | [
"Absolutely. As an example, recently there was an outbreak of ",
"Sea Star Wasting Disease",
" which killed a significant portion of all the starfish on the west coast of North America. It was caused by a single strand DNA virus. It was extremely virulent, and spread up and down the coast in fairly short order.... | [
"Oh yes!! In fact viruses are by far the most numerous biological replicating entity in the ocean. The numbers are somewhat hard to believe and nearly impossible to put into perspective. There are an estimated 10 million viruses in every milliliter of surface sea water, meaning that every liter of sea water has mor... | [
"Yup. That's how the coccolithophores ecosystem works, which is what created things like the white cliffs of dover. ",
"https://blogs.scientificamerican.com/expeditions/you-wanted-to-know-what-is-this-virus-that-infects-the-phytoplankton-part-one/",
"And here's a nifty little podcast on it:",
"https://www.wny... |
[
"When the sun expands to it's max in the latter stages of its life, will the conditions in any of the outer planets or their moons become ideal for life?"
] | [
false
] | If so, how much time will that new life have to thrive? I'm thinking, could we plant capsules in those planets to sit there and just wait for the right conditions. | [
"Maybe.",
"The inner planets will become too hot, and the gas giants are not ideal for life as we know it because of the immense pressures and lack of sunlight underneath their atmospheres. However, some of the gas planets' moons may be suitable for life.",
"There's not a lot of certainty in the calculations fo... | [
"Very good point. Will we reach a moment where we'll say \"what's the point?\" And cease any effort to continue our race."
] | [
"Maybe ten years later you fly off again because you want to see the crap nebula or something.",
"Who wants to go see the crap nebula? By our normal naming conventions, I doubt that it would be a very nice place.",
"Such a human existence as the self-sufficient spaceships is probably an inevitability, unless we... |
[
"Self-Fueling Pure Oxygen Car Engine"
] | [
false
] | null | [
"This has been removed because the question is based on fundamentally flawed premises. Please conduct some background research and revise if your question if you wish to resubmit.",
"Some of the most commonly seen mistakes are listed in the ",
"FAQ.",
" under respective fields."
] | [
"That is my question though, what is that flawed premise?"
] | [
"You would need energy to separate the oxygen from the air, and hence you'd need another energy source to do that first. Also, the energy density of air at room temperature and pressure would not be enough to run a modern sized car."
] |
[
"With the recent discovery of the new habitable planet, what \"checklist of events\" needs to happen?"
] | [
false
] | null | [
"Your question is very vague/open-ended, but here's the list as I see it:",
"Develop new propulsion technology. (Warning: speculation.) This will probably take hundreds of years for the type of leaps that must be made.",
"Travel to planet. Present-day unknowns like \"how to ensure the planet is habitable\" w... | [
"Do you mean \"checklist of events\" in terms of further studying the star and its planets, or do you mean developing interstellar spaceflight?"
] | [
"Yeah sorry for the vague question. Just posted on a whim, but yes, I do mean interstellar space flight "
] |
[
"Why does hair come in just a few colors? And why these colors?"
] | [
false
] | As the title says - why can we only have different shades of a few specific colors of naural hair and why can hair only have one of these particular colors and not, say, green? | [
"Layman.",
"There are two major natural pigments found in hair. Eumelanin is black or brown. Pheomelanin yellow or red. Our hair colours are limited to what can be produced by mixing these two pigments in various quantities.",
"I can't say why we never evolved to produce another pigment (like a green pigment)."... | [
"Because humans did not evolve in forests, but in savannas."
] | [
"Would green make you blend inn the forest?",
"BTW fun fact, there are no green mammal. "
] |
[
"Removing salt corrosion from FPLC machine"
] | [
false
] | Hello askscience, I work in a research lab where I run a couple of FPLC (fast protein liquid chromatography) machines. The fractionation machine that collects samples from the FPLC will occasionally spill salt-containing proteins onto its metallic base, which over time has led to a significant accumulation of salt and corrosion/pitting of the base. There are other minor salt spots on the FPLC itself. It turns out, salt is rather difficult to remove. Even the minor salt spots aren't really effectively removed with repeated scrubbing with water or dilute acetic acid. I've tried soaking the major salt spot on the fractionation machine in acetic acid to basically no effect. It's hard to find information about dealing with corrosion online. I've seen people advising applying an electric current to the corrosion and other sorts of complicated solutions. Being in a large research lab, I have an extensive amount of reagents at my disposal. So, askscience, is there a simple, straightforward solution to my problem? I'll be back at the lab for a bit shortly and may post a picture for reference. | [
"Try ",
"r/askscitech",
" as well."
] | [
"I've not encountered this specific problem with FPLC, but I have cleaned some corrosion from labware (and battery terminals) using Coca-Cola, and oddly, it works well. So if you dont' want to mess with sugary things, maybe trying a fairly concentrated (pH < 4) phosphoric acid preparation would work."
] | [
"Cola/phosphoric acid was actually one of the solutions I'd considered, but I never did try it. Thanks for the suggestion.",
"And yeah, this isn't a question that's really specific to FPLCs. It's just extra information."
] |
[
"Would an Argon-Oxygen atmosphere be breathable?"
] | [
false
] | Could humans breath an Argon-Oxygen atmosphere? For bonus points: what about a Neon-Oxygen atmosphere? | [
"Yes, although the act of breathing would require more effort due to density differences. The partial pressure of oxygen is the critical factor, and at an appropriate % of oxygen, the partial pressure is the same. ",
"Deep sea divers actually use ",
"oxygen-helium mix",
" to avoid complications at higher pr... | [
"Perfluorocarbons are mad shit! Good point about the viscosity problem.",
"I wonder if the blood could be infused with oxygen outside the body with an IV line, removing the need to breathe altogether. Maybe humans could get down to a kilometer this way? I get the feeling the OHS folks wouldn't like it, in any cas... | [
"It's been a long-term project to make synthetic blood actually:",
"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5084831/",
"There are problems, but the carrot of replacing the need for blood donors is a big deal."
] |
[
"Gravity sucks. But where and/or how does the rotation begin? We see rotation in the kitchen sink, the toilet, dust devils, tornadoes, hurricaines, our solar system, our sun, and our galaxy. WHY DOES EVERYTHING SPIN?"
] | [
false
] | null | [
"This usually has to do with conservation of angular momentum. Imagine a box filled with particles that travel in random directions at random velocities. All those particles together have a total angular momentum that is constant over time. If the particles start clumping together you will start to notice a rotati... | [
"I'm seeing lots of wrong answers. Conservation of angular momentum exists. It matters. That does not explain why a sink does not suck towards its center. It doesn't explain why galaxies and planets rotate about a center. How did they start rotating when they didn't have any spin to start?",
"Easy answers first. ... | [
"/u/MrPennyWhistle",
" aka Destin, from Smarter Every Day, and Derek ,from Veritasium, did a pair of YouTube videos a couple of months ago with a really insightful experiment demonstrating drain swirls. They speak in depth about the origin of the spin, explain how the rotation of the earth contributes, and abou... |
[
"Do all planets have seasons? If so, do they do anything?"
] | [
false
] | null | [
"Seasons are caused by the axial tilt of our planet. The axis around which the Earth rotates isn't perpendicular to the plane in which the Earth orbits around the Sun (the orbital plane). Because of this tilt, each hemisphere undergoes cycles in which it alternates between being \"turned away\" from the Sun and bei... | [
"Some more details:",
"Mercury has such a slow rotation (which is coupled to its orbit) that the concept of a day and a year get somewhat mixed. I‘m not sure how meaningful the concept of seasons would be there.",
"Venus also has a slow rotation but the thick atmosphere covers it and makes temperature variation... | [
"To address the question \"do they do anything\", yes. Mars has very strong seasonal changes, including changes in wind patterns and the formation and evaporation of carbon dioxide (dry ice) at the poles. As much as a quarter of the atmosphere freezes out and re-evaporates every year! Its dust storms also depend... |
[
"What forms might our galaxy take after it merges with Andromeda?"
] | [
false
] | So, I just read that in a few billion years, the Andromeda galaxy and the Milky Way will . What will the resulting 'Supergalaxy' look like? I imagine the spiral arms we're so familiar with will be torn apart, but after looking at the video on that wikipedia link, there seems to be a big cluster of material that is wholly ejected. What will be the fate of these unfortunate stars? | [
"The two will first form an interacting pair, which will look quite irregular, like the ",
"antennae galaxy",
". In the long run (and with subsequent collisions) stellar movement should become sufficiently uniform to form an elliptical galaxy. This is also the process seen in the video you linked.",
"The star... | [
"The stars and other (edit: gravitationally bound) stuff in the galaxy will move at lower angular speeds the further away they are from the galactic center of mass (for a simple model, see Kepler's third law). \nThe arms also spin, but at a fixed angular speed. Their angular speed of rotation does not have to chang... | [
"Does this imply that the arms don't spin (pinwheel style), just the stars and matter of the galaxy do?"
] |
[
"If I went back to the Cretacious era to go fishing, what would I catch? How big would they be? What eon would be most interesting to fish in?"
] | [
false
] | null | [
"This is a fascinating response. So informative on something I never knew I wanted to know."
] | [
"This is a fascinating response. So informative on something I never knew I wanted to know."
] | [
"A number of reasons have led to the changes we see regarding armor in fishes. Armor plating was in vogue because the early seas were dominated by invertebrate predators with all manner of spikes, claws, and jaws to make short work of soft-bodied organisms. The majority of early organisms were pretty slow by desi... |
[
"How dissimilar are particles and forces on a microscopic level?"
] | [
false
] | Obviously, they behave very differently on a macroscopic scale, but I and others would be curious to know what separates particles and forces at the base level. What, if anything, makes forces act as forces (i.e. causing acceleration), and particles as particles (volume, mass, etc.)? I understand that there is probably not any single well defined answer, but it would be interesting to hear the prevailing theories from different fields. | [
"You know Newton's law, right? ",
" is the way it's usually taught in schools; ",
" being the more useful way of writing it.",
"Newton's law says, in essence, that a particle will accelerate in a way that's inversely proportional to its natural resistance to acceleration — quantified as something called ",
... | [
"Microscopically, (point) particles do not have volume. They do have a notion of (rest) mass, and charges, &c. They are excitations of a certain field defined over all spacetime.",
"\"Forces\" are caused by interactions with \"force-carrier particles\" (a.k.a. \"gauge bosons\"). Gauge bosons are particles; they a... | [
"Various intermolecular forces... electrostatics, charged particles, magnetism, gravity (not so much at small scales), van der Waal forces.",
"Different phenomena scale with different considerations... e.g. pressure depends on area, magnetism on distance. As you changed scales the relative contributions of diffe... |
[
"How do deep-sea organisms withstand crushing pressure?"
] | [
false
] | What cytological changes or other explanations are there for deep-sea life to withstand the high-pressure environment? I'm having a hard time getting past the thought of a submarine imploding upon itself when it gets to a sufficient depth, so what imparts resistance to this pressure? And does that make those types of things intolerant of a relatively low-pressure system up at the surface? If you took a fish normally living on the deep-sea floor, would its cellular architecture hold at sea level? | [
"Here is a really great article from Discover about just this question: ",
"Link to article",
"."
] | [
"As long as the pressure \"within\" the organism is the same as the pressure outside, it would be fine I think. By within I mean all body cavities and cellular ones. So if you take humans very slowly (equillibrating them to the pressure as we proceed; not sure if its fully possible), we should theoretically be able... | [
"Perfect, explained it well, even though it takes a while to understand overly-simplified cell biology.",
"Yayanos, Somero, and others have discovered a few of the adaptations that permit deep-sea bacteria— and the cells of higher organisms— to thrive under high pressure. For one thing, deep-sea creatures make th... |
[
"How can I comprehend the taste buds of another animal? For instance, if I were a vulture eating rank roadkill, or a deer eating fresh clover."
] | [
false
] | Dogs are the weirdest. Some will eat anything, while others spit out fruits and vegetables and look at you like you just handed them a stick. And why do some people like black licorice or cilantro? | [
"A taste bud is cells that compose or support chemoreceptors. Chemicals with specific shapes attach to specific receptors, and this is communicated to the brain to be processed as a taste type, and can be interpreted as desirable or not. Animals have genetic predispositions for specific tastes, and there is varia... | [
"While the mechanics are the same, it is interesting to note, however, that 'heat' or 'spiciness' comes about via chemical interaction with pain receptors rather than the pathway involving taste buds. The same basic principles apply, though. The real difference is just that different receptors and nerve bundles a... | [
"I've heard this, and know that birds (mostly) aren't affected by capsaicin, which is why you can use chili powder on birdseed to keep squirrels out of it."
] |
[
"Is there an element/compound that is denser as a gas than it is as a solid?"
] | [
false
] | Title | [
"Generally, solids and liquids are about a thousand times more dense than gases at temperatures and pressures we're accustomed to. To increase the density of a gas, one would decrease the temperature and increase the pressure. At too low of a temperature/high of a pressure, the gas would condense into a liquid, the... | [
"Hey thanks for that! That was very informative, and luckily I'm in a chemistry class on equilibria right now, so i understood it! What pressure do the anvil cells reach to? Is there a maximum pressure we could obtain with our knowledge of the elements?"
] | [
"I don't have any professional experience with diamond anvil cells, but from some quick googling it looks like the state of the art is somewhere >700 GPa (about 7 million atm). Here's a ",
"news article",
" from 2012 summarizing some work in that direction. Apparently the limiting factor at those pressures is t... |
[
"Why is radioactive decay exponential?"
] | [
false
] | Why is radioactive decay exponential? Is there an asymptotic amount left after a long time that makes it impossible for something to completely decay? Is the decay uniformly (or randomly) distributed throughout a sample? | [
"Exponential decay comes from the following fact:",
"The rate of decay is directly proportional to how many undecayed nuclei there are at that moment.",
"This describes a differential equation whose solution is an exponential function.",
"Now, why is that fact true? Ultimately, it comes down to two facts abou... | [
"To add some basic math. Lets imagine there are 1m nuclei. If each has a 50% chance of decay per year, you would decay somewhere around 500k nuclei in year one. Well, next year you start with 500k, so you'd decay 250k. Next year 125k.",
"500k > 250k > 125k > 62.5k . Exponential and assymptotic.",
"Obviously the... | [
"Each isotope. E.g. different uranium isotopes have vastly different half life. (There are also exited states of nuclei, thus even the same isotopes may have different half life.)"
] |
[
"Have we been able to successfully create matter from energy?"
] | [
false
] | Since we theorize that that's the basis of the big bang, have we been able to prove it experimentally, albeit in a much more controlled environment on a much smaller scale? | [
"Yes, that's what happens all the time at CERN, Fermilab, etc... : particles are accelerated so that they gain an enormous amount of kinetic energy. This kinetic energy is then converted into new particles during collisions."
] | [
"If you mean giving a particle energy as in accelerating it to a high velocity (giving it kinetic energy) no. That would violate the conservation of energy because from the rest frame of the particle, it is not moving, and therefore has no kinetic energy in its own perspective, and according to relativity, physics ... | [
"I think in TUVegeto137's example, the collision must occur for the new particle to be created. I'm curious if new matter could be created simply by giving a particle more energy with nothing else (like a collision). I think this is what you are wondering as well.",
"Also, can pure energy exist separate from any ... |
[
"Are there hyperconic sections?"
] | [
false
] | [deleted] | [
"TL; DR: Yes, there are. The easiest way to get to this is to look at the algebraic formulations of the geometric objects.",
"Let's do this!",
"For a start, let's consider conic sections (Non-Hyper). ",
"The points in a cone are characterized by the equation ",
"x",
" + y",
" = z",
" , (I)",
"i.e. a... | [
"Since slicing a dimension 4 object with a dimension 2 object creates a dimension 3 object (at least as I understand), would slicing the hypercone (4D) with a space (3D) create 2D objects which would be our normal conic sections, or would they be different?"
] | [
"It depends and is not easy to answer.",
"Let me ask the same question for the conic sections:",
"If we take for granted that the cone is a 3d object and the planes we intersect it with are 2d objects, which are the results? A point, A circle, hyperbolas, parabolas. Which 'dimension' do these objects have?",
... |
[
"Have non-human Great apes ever been seen communicating with each other in sign language?"
] | [
false
] | There's a great scene in Rise of the Planet of the Apes where an old circus orangutan starts signing to the main chimp who signs back and I'm just wondering if it has ever been seen in real life. | [
"Most great apes don't get beyond using very, ",
" simple vocabularies. Most of the exceptions are listed on ",
"Wikipedia",
". The wikipedia article is actually quite thorough (make sure you read the references for more info)."
] | [
"We have seen apes spontaneously use meaningful gestures with each other. ",
"Here's one example.",
"Instances of apes using fully grammatical sentences in ASL or any other sign language are, to say the least, extremely rare. And as far as I know, there's never been any observation of apes signing full sentence... | [
"Communicating in sign language in the wild, no. But, they do communicate in other ways and have rich emotional languages. ",
"http://en.wikipedia.org/wiki/Emotion_in_animals#Primates",
"Chimps have even been caught in the wild lying. A baby chimp wants another chimps food will \"cry out\" with a sound that a... |
[
"How exactly does an induced-fit model work?"
] | [
false
] | How do enzymes know when to change the size/structure of their active site when different substrates are presented? Also, how do these enzymes organize their substrates so efficiency is maximized? (so do they do all of substrate A at once then substrate B, or do they alternate, etc) | [
"Biomolecules are not rigid. If you look at NMR determined solution structures you find multiple, similar conformations. Also, they do not \"know\" because they do not \"think\" or \"feel\" or \"want.\" The only determinant is what is stable.",
"In terms of an enzyme there is a catalytic pocket that a substrate f... | [
"Fluoxetine is correct",
"Molecular dynamics allows for computer models of proteins and their binding to substrates. I've included links to a couple videos generated by molecular dynamic models. Note how much vibration exists in the molecules.",
"An Introduction to Molecular Dynamics",
"A basic introduction t... | [
"Exactly, I did not outright state that, but as I stated enzymes catalyze the reaction. A catalyst is a general term for anything that increases the rate of the reaction. I discussed how the rate is increased when looking at enzyme substrate interactions. There is much more to this, but the basic concept is that th... |
[
"Can exposure to an incredibly high dose of radiation lead to instant death?"
] | [
false
] | If a person, standing in plain clothes is exposed to an intense radiation source (200+ roentgens / hour) , is it possible for them to die instantaneously? | [
"Yes, high enough acute doses can prevent neurons from firing correctly and lead to instant death. If you were to pull out a fuel assembly from a nuclear power plant and place it on the wall and run at it from 50 feet away. You will die before touching it."
] | [
"This has actually happened. Bugorski took 300,000 rads to the head from a beamline in 1978 and lived. ",
"https://en.wikipedia.org/wiki/Anatoli_Bugorski",
"http://www.wired.com/wired/archive/5.12/science.html"
] | [
"For any sort of magnetic field that we can create on earth, no, with patients with pacemakers an exception due to those device's sensitivity. The magnetic fields in MRI machines are 1-3 Tesla. This is similar to the magnetic field inside a loud speaker coil. People have levitated living organisms in strong mag... |
[
"Is there a closed-form equation for this type of curve generated by connecting points on a graph?"
] | [
false
] | This shows the curve which is generated by connecting the points (0, 0) to (10, 0), (0, 1) to (9, 0), and so on. Of course, the endpoints don't have to be (10, 0) and (0, 10), they can be (X, 0) and (0, X). My question is: as I increase the number of subdivisions, e.g. connecting (0, 0.1) to (9.9, 0), until the spacing between lines becomes an infinitesimal quantity, is there a closed-form equation for the resulting curve that bounds all the lines within, assuming I use the endpoints (10, 0) and (0, 10)? My guess, just from looking at the rough shape of the curve, is that it is the arc of a quarter-circle with the center at (10, 10). Or is it not as simple as that? | [
"The curve turns out to be neither a circle nor a parabola, but a curve of the form",
"√(x) + √(y) = √(K)",
"where ",
" is some constant (K = 10 in your example). Okay, so how do you prove that? Well...",
"We first consider the collection of all line segments, one endpoint of which is (0, a) and the other e... | [
"To add to ",
"/u/Midtek",
"'s excellent answer for this specific example, the ",
" is a actually ",
"a piece of a parabola",
". For three points A B and C, with B in the middle, you can define the curve parametrically as:",
"P(t) = A (1-t)",
" + 2 (1-t) t B + C t",
" for 0 ≤ t ≤ 1",
"We'd call it... | [
"I see you already have real answers, but here's a quick visualization I made, along the lines of what ",
"/u/camkatastrophe",
" posted, but with a bit simpler presentation. you can see that the curve is pretty close at the top, bottom, left, and right edges, but gets a bit over-round in between:",
"http://im... |
[
"Blood type translations from"
] | [
false
] | Hi Reddit Ask Science, I hope this is the right place. I am an immigrant from Russia and I looked in my old passport there was a blood type: "ab(IV) rhes poz" What is it equivilant in the western blood type systems if I want to donate blood? What are the different blood type systems for and what sets them apart? | [
"That sounds like it would map to 'AB' 'rhesus positive' but I am not an expert and might be totally wrong.",
"If you did donate blood they will take their own tests, most likely."
] | [
"I tried but the other systems are in other languages, making it hard to impossible to understand in google translate. It would be cool if a scientist explain it."
] | [
"You're correct."
] |
[
"Scientists are excited to find water on Mars because it can be used to create hydrogen and oxygen (rocket fuel and breathable air). But splitting water requires more energy than you get by burning the HHO. How does science foresee using the water effectively to fuel/run/support a base on Mars?"
] | [
false
] | [deleted] | [
"Would probably be most efficient to build one on mars from scrap."
] | [
"Would probably be most efficient to build one on mars from scrap."
] | [
"Hydrogen and oxygen will be used for propellants and possibly portable turbines (like high-altitude drones).",
"The larger stations would be powered by solar (low power output because of less solar radiation than on Earth, but still usable) and nuclear (for obvious reasons, although reactors would be big and hea... |
[
"Shouldn't audio equalizers reflect/invert the differences in perceived loudness along the frequency spectrum?"
] | [
false
] | has a frequency x sound pressure x perceived loudness contour curve, allegedly sourced from ISO 226. I figure the curve shape even shifts for different levels of perceived loudness (long bass waves reach very far, as anyone who's been a block away from a dance party knows), but computers and dedicated circuits should be able to adjust for this smartly as volume is changed, etc. (The problem, of course, would be telling people to adjust volume in their software and not in the system, or in the amp/external eq and not the sound source and so on. Psychologically, this is very hard to guarantee.) | [
"Acoustical engineer here. There is no reason for a signal processor to apply this adjustment to the spectrum because your ear will naturally do this.",
"The graph in that link is known as an \"equal loudness\" curve. The loudness is expressed in \"phons\" and is represented as a function of both frequency and so... | [
"Acoustical engineer here. There is no reason for a signal processor to apply this adjustment to the spectrum because your ear will naturally do this.",
"Answered! Thanks :)"
] | [
"It seems what you would require is a system that would also monitor your proximity to the speakers in order to properly attenuate or compensate. This poses not only the problem of being inaccurate, but also of compromising the sound quality for multiple listeners in order to achieve higher-fidelity for one. ",
... |
[
"Why are the sidereal year and the tropic year related?"
] | [
false
] | Why is the tropical year (tilt of the earth back to same sun position) related to the sidereal year (orbit around the sun to the same star position/one time around the sun) at all? Is there a mathematical relationship? Could we have something like 4 or 8 tropical years for every sidereal year? | [
"The difference in the first place is due to ",
"axial precession",
", the rotation of Earth's axis. If this didn't happen, then sidereal and tropical year would be exactly the same. The reason why they are almost the same is that the precession is very slow. It takes tens of thousands of years for the axis to ... | [
"Assuming we are always referring to the season in the Northern-Hemisphere.",
"Look at ",
"this diagram",
" depicting the seasons. Note that the angle of 23.5° effectively doesn't change. If it actually didn't change there would be no difference between sidereal and tropic year. It fluctuates a tiny bit re... | [
"A tropical year is 365.2422 mean solar days, and a sidereal yar is 365.256 mean solar days, or about 20 minutes longer than a tropical year. This never changes.",
"A tropical year is measured by the interval of time between one vernal (spring) equinox to the next. Equinoxes occur when the ecliptic intersects the... |
[
"Do transcription factors bind RNA?"
] | [
false
] | Since it is known that genes can be regulated by intragenic regulatory elements, and do so in a sequence-specific manner, is it possible for some classes of transcription factors to recognize these sequences in the corresponding transcribed RNA? If so, might it be possible to disrupt TF binding in a site-specific manner by using an engineered RNA 'sponge'? | [
"In answer to the first part of your question - ",
"\nThere are actually several known RNAs which act in living cells in the way in which you describe, acting as \"decoys\" for transcription factors, thus preventing their binding to the DNA (review article: ",
"http://www.nature.com/nature/journal/v482/n7385/fi... | [
"Since RNA is transcribed as a single strand, it generates a complex secondary structure like a protein strand - this would disrupt the traditional motifs used by transcription factors to recognize DNA such as basic loop helix binding domain.\nThere are hundreds of ways to engineer mimics or other inhibitory elemen... | [
"There are some CRISPR-Cas based systems that can bind RNA. Specifically type III systems. There is less known about them, but some researchers have successfully targeted and bound RNA. The one specific paper included below uses the protein csy4 among other regulatory elements to create programmable gene circuits."... |
[
"If the universe is 13.7 billion years old, how come the observable universes edge is 46-47 billion light years away? Should it not be 13.7 billion light years away?"
] | [
false
] | null | [
"Because the universe is expanding \"faster than the speed of light can cover spacetime\". Imagine the earth was the universe and it is expanding at a high rate (getting bigger in scale). If you were living in New York and China was some light years away, the earth is now expanding faster and faster (growing in siz... | [
"It doesn't work that way, because it's not expanding from a central point, so the light doesn't have to travel from \"the place where the big bang happened\" towards \"the boundaries\". It's expanding from everywhere, because the big bang itself was, if you want to put it this way, everywhere (space was infinitely... | [
"From what I understand, something we see as 40 billion light years away now wasn't 40 billion light years away when the light was emitted. It was closer, but the space between us and it has gotten bigger.",
"A poor analogy would be that if a person moving away from you yelled at you, by the time you heard their ... |
[
"Could a nuclear explosion create artificial diamonds?"
] | [
false
] | null | [
"Apparently detonation nanodiamonds are a thing. ",
"wiki",
"These are from conventional explosions. A nuclear weapons does use conventional high explosives in the reaction. You would need an abundance of carbon. Modern weapons would only have the carbon in the high explosives. Everything else is not a ca... | [
"I'm extremely skeptical that any diamonds could have been formed at ground zero at Hiroshima. The overpressure (pressure above normal atmosphere) from a 20 kt airburst at a similar altitude to the Hiroshima strike ",
"is around 16 psi",
", which isn't exactly diamond-creation range. The Hiroshima bomb was q... | [
"an abundance of carbon",
"Hiroshima was mostly wood. If you looked at the soil layer by layer you'd probably find one that would be both rich in nanodiamonds and helpfully tagged with radioisotopes so you can be sure you have the right time. It was an airburst but it was still pretty intense in the center.",
"... |
[
"Are stars capable of using fusion to form all elements?"
] | [
false
] | null | [
"Normal stellar fusion can only get you up to nuclides around the stable isotopes of iron. To go beyond that, other processes are needed. For example, the s-process and r-process."
] | [
"Could you explain a little more what the s-process and r-process are?"
] | [
"The Wiki articles for ",
"s-process",
" and ",
"r-process",
" are a good start."
] |
[
"How do ships in space measure their velocity? Do they have to calculate it based on their thrust and weight (which is constantly changing as it burns fuel)."
] | [
false
] | null | [
"usually isn't terribly accurate",
"For spaceships and ICBM's they ",
" terribly accurate (and expensive). A professor told me about an IMU left on while sitting on a table for a day or two. It was accurate enough that you could clearly see the slight movement of the thing as the building expanded and contrac... | [
"One method is to use inertial sensors to measure acceleration and angular velocity. By integrating those you can get some idea of where you are, but it usually isn't terribly accurate. Edit: Apparently this method is a lot more accurate than I was led to believe. ",
"Another method is to look for specific start... | [
"The NASA guy was right- velocities are always measured relative to something. It's really the only way they make sense. Here on Earth we have a very natural coordinate system. We assume the Earth is not moving, and we measure how quickly we pass over the surface of the Earth. But, we are still measuring our veloci... |
[
"Why is ethanol drinkable but methanol, 2-propanol, etc. poisonous?"
] | [
false
] | From an organic chemistry perspectice, what significant difference does one extra carbon make? I'm an organic chemistry student and I've yet found the answer. | [
"As others have already said, it just so happens that some alcohols have toxic breakdown products and others don't. Since you're an organic chem student, some details may be interesting:",
"Methanol and 2-propanol are processed by the same enzymes that ethanol is. First Alcohol Dehydrogenase oxidizes the -OH grou... | [
"The reason that methanol and other alcohols are considered poisons is due to the byproducts that are created when your body breaks them down.",
"Certain types of antifreeze are extremely toxic because of the presence of ethylene glycol. ",
"Here",
" is a good source for what happens when your body breaks it ... | [
"Interestingly enough, the treatment for methanol poisoning is intravenous ethanol, as it uses the same enzyme (alcohol dehydrogenase) that converts methanol into its toxic products. "
] |
[
"How do rashes target specific parts of the body?"
] | [
false
] | I came across which results in rashes on the palms of the hands and feet. “It’s one of the few rashes where you’ll have bumps or blisters on the palms and soles of the feet,” Dr. Derickson says. "Usually rashes on the whole body spare those parts, so that's one of the give-aways." I've always thought of rashes as being the result of a physical irritant, so you get the rash wherever the thing that causes it touches you, or it's in your bloodstream and you get breakouts pretty much all over. But this particular virus causes rashes in specific areas. How does it do that? And the claim I quote above suggests that most rashes don't happen on the palms of soles and feet, so why is that? How are these rashes able to target specific areas of the skin? | [
"I believe the answer is \"we don't know\" (though I'd love to hear what the answer is if we do know. Any dermatology buffs around?)",
"Rashes from different disease processes can take stereotyped albeit different forms, I'm not sure why. H, F &M disease is an interesting example. There are many others which have... | [
"Hand Foot and Mouth Disease can be caused by a couple of viruses, including a coxsackie virus and enterovirus 71 (EV71). While the coxsackie virus causes more Hand Foot and Mouth Disease cases, I found ",
"this",
" paper that talks about EV71 and its tropism. Tropism is the type of cells that a virus can infec... | [
"Rashes are caused by irritation/damage to the skin, often by direct contact (as you mention above) such as touching acid, but sometimes as the result of processes that affect the whole body such as a virus. ",
"Coxsackievirus is the virus behind Hand Fooot and Mouth disease, and to echo Wdenners, we really don’t... |
[
"What happens to an ant if I carry it miles away from its colony?"
] | [
false
] | [deleted] | [
"According to ",
"the wikipedia article on ants",
", an ant cannot join another colony because its colony scent (or lack thereof, after a certain period of time) does not match the new colony's scent. It will be attacked (probably).",
"The article does list an exception: ",
"The Argentine Ant",
". That sp... | [
"I only knew because this question was asked before :) ",
"http://www.reddit.com/r/askscience/comments/rdg3g/what_happens_if_an_ant_is_released_outside_in_a/"
] | [
"I only knew because this question was asked before :) ",
"http://www.reddit.com/r/askscience/comments/rdg3g/what_happens_if_an_ant_is_released_outside_in_a/"
] |
[
"How would the energy of an explosion or bomb be dissipated in space if there is no medium to carry a shockwave?"
] | [
false
] | null | [
"The energy would dissipate as an expanding ball of hot gas or whatever debris is left.",
"\nThe sockwave from a blast magnifies the damage but it isn't essential. If there isn't a medium to carry a shockwave the energy simply stays in the explosive."
] | [
"If there isn't a medium to carry a shockwave the energy simply stays in the explosive.",
"It is just worth noting that sometimes the effect you see is ",
" of interactions with the medium. With nuclear weapons, for example, the \"blast\" wave in the atmosphere is mostly produced by heating of the atmosphere. S... | [
"The molecules that are produced in the chemical reaction of the explosion would move away from it at high speeds without hitting any other gas molecules. While in a medium the kinetic energy of those molecules is transferred to medium molecules, when there is no medium the reactants do not loose kinetic energy, so... |
[
"How do you estimate the percentage of species not found if you do not know the total the number of species (since they haven't been discovered)?"
] | [
false
] | null | [
"A field scientist will not likely have enough time to survey an entire rainforest. However, one can easily survey several 10ft by 10ft patches within the area. Suppose you're in an area that's as large as 1 mile by 1 mile. You select several 10x10ft patches and count all the insects in those locations. You find th... | [
"You are absolutely right. We use a tool called species accumulation curves to estimate how often new species will be encountered as you survey additional area. Species accumulation is nearly universally an asymptotic function--it levels off as you go. For example, in the first 10x10 plot, each of the 5 species you... | [
"Also, on a more global scale and over a longer period (decades, centuries): Looking at the rate of discovery of new species. I've no idea how the graph looks like, but the rate should decrease over time. From that you may make inferences. Of course, if there are new developments in, for example, oceanography, like... |
[
"How do air fresheners that claim to remove bad odors work?"
] | [
false
] | Some air fresheners claim they can remove certain odors instead of simply masking them. How does this work chemically? Also, how can these air fresheners be scented themselves - wouldn't whatever's neutralizing the bad odors neutralize the fragrance as well? | [
"As a chemist who knows how this stuff works, I endorse the Edit as the correct answer."
] | [
"Feel free to bury this under a more scientific answer, but I believe air fresheners that claim to remove odors do so via antiseptic properties. I suspect they kill bacteria that cause odors. ",
"edit: Some research has proven my suspicions wrong. Apparently aerosolized glycols in air fresheners, particularly t... | [
"If you could somehow detach the triethylene glycol from the particles, they would still smell. It tends to bind pretty tightly though.",
"To be able to smell something, you have to be able to get a significant portion of the 'odiferous particles' back into the air. So while they probably will accumulate on the g... |
[
"How can we recreate structures from bones?"
] | [
false
] | How can we account for body parts made of cartilage, where muscle mass appears, etc.? | [
"where muscle mass appears, etc",
"Attachments of muscles to bones can be identified. The muscle masses can be inferred from a \"connect the dots\" approach, ie, this muscle goes from x to y and would bear z load."
] | [
"Soft tissues exhibit mathematical relationships with regard to their proportions and suitability to purpose. By examining existing organisms, we can determine how musculature and cartilage etc. must conform to bone structure, and the recreations follow these relationships."
] | [
"I don't think I understand your question, but if you are asking how we can 'create' different body parts from bones (i.e. bone marrow), it is because there are ",
"stem cells",
" within bone marrow that can be differentiated into bone cells, cartilage cells, and fat cells.",
"Note that in tissue engineering ... |
[
"Why is the derivative of the area of a circle its circumference, and the derivative of the volume of a sphere its area?"
] | [
false
] | So the area of a circle is πr2 and its derivative is the circumference, 2πr. The same happens with a sphere. The volume is (4/3)πr3 and its derivative is the surface area, 4πr2 . Is this a coincidence? Also, can we use this property to predict similar quantities for circles/ spheres of higher dimension (its 'volume' so to say)? | [
"Which simplifies to 2pi*5 m. 30 metres of cable to raise it 5 metres around the ENTIRE GLOBE."
] | [
"Check Here"
] | [
"This reminds me of a question someone asked me recently:",
"You have a cable laid flat around the entire globe. You want to raise the entire thing 5 metres off the ground. How much more cable do you need? (Assume no obstructions, etc).",
"The answer just isn't intuitive."
] |
[
"Trying to make a \"Faraday Glove\" to insulate my hand from large static discharge, help?"
] | [
false
] | I haven't actually started fabrication yet, but I want to be sure I'm not barking up the wrong tree. I have a Van De Graaff generator and I want to make a chainmail glove that would be grounded so that I can discharge the dome without feeling anything. I've seen pictures and videos of guys staying relatively comfortable while discharging huge Tesla coils through full body Farady Suits, so I know this sort of thing is possible, but I don't know if something as simple as this glove: connected to ground would be enough to completely reduce sensation of the shock. Thoughts? | [
"Theoretically that would work (assuming the glove conducts well), but maybe an engineer can expand on some practical concerns like:"
] | [
"If the glove is made of interlocking ringlets rather than woven metal fibers then there will be a lot of air-gaps and poorly conducting contacts that might cause parts of the glove to heat up a lot, or even arc to your hand. As much as possible you want to have continuous wires for the electricity to travel down."... | [
"Best material to use/coating to apply",
"I wouldn't coat the glove, best material... got money? silver-plated steel would be the best, otherwise i'd say galvanized. I'd be sure to protect against corrosion with so much surface area. ",
"Coverage of body, how far away does the rest of your body have to be away"... |
[
"What Magnesium Compound is found in most brands of mineral water?"
] | [
false
] | Magnesium Oxide, Sulfate, etc? Which one? Don't ask me why I want to know, but it would be greatly appreciated! EDIT: Thanks for the answers! Upvotes given. | [
"Well, unless magnesium is precipitating as a salt, it will be present as an ion in solution with whatever counterions happen to be floating around and it won't necessarily always be the same counterion if it has more than one to choose from. Just pick up a bottle of mineral water and look for counterions that the... | [
"it's MgCl2. Chloride is the most common anion on earth. (compare to Europa where sulfate is most abundant) MgSO4 is also used as a laxative, I doubt I would buy that water.",
"\nThe reason (most likely) is that when MgCl2 dissociates in water, it makes a very slight amount of MgOH+ by hydrolysis of water, makin... | [
"that's because there is no over-the-counter source of MgCl2, but that doesn't mean that's how brand names make it."
] |
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