title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
|---|---|---|---|---|---|
[
"How can you tell how much time a patient has left to live when diagnosed with (any kind of) cancer?"
] | [
false
] | Additionally, how can you tell how much time a patient has with kind of terminal illness? - Thank you all for your informative answers! | [
"You can never be certain. Each person, each cancer, and each treatment is different. But we have ways of discriminating between certain types, classes, and levels of severity in different cancers. We can classify tumors based on their size, cell type, location. Additionally, we can identify whether a tumor has... | [
"Generally, we look at the characteristics of their tumor as well as their functional status. Groups look at survival both prospectively (watching people going forward in time) and retrospectively (analyzing patients from the past). The results of these studies are often reported using Kaplan-Meier curves. ",
"He... | [
"You can find the general cancer statistics in several places:",
"Survival curves out to 10 years",
"A discussion about presenting the data that has some longer survival rates",
" scroll down to get to the nicer presentations of the data.",
"How far the cancer has spread is a factor, so if you have that inf... |
[
"How can the exoplanet HD 100546 b possibly be more than 5 jupiter diameter in size?"
] | [
false
] | So I recently came to know about this planet/brown dwarf thing. It stands at about 20 jupiter masses and is 5-6 larger in size. One source for information of the planet I have heard that all brown dwarfs are supposed to be about the same size due to the increase in both gravity and pressure when mass increases. Then ho... | [
"The HD 100546 system is very young, still hosting a protoplanetary disc. HD 100546b is still a protoplanet, and is still be contracting towards its final size.",
"It is worth noting that the radii of low mass stars are currently poorly understood, with a significant fraction of M dwarfs having radii larger than ... | [
"Just to add, this is definitely not a hot Jupiter as it has quite a large semi-major axis."
] | [
"...although if you believed the Wikipedia article until a few minutes ago, it supposedly had an orbital period of 6 days! No clue where that number came from."
] |
[
"How do I go about learning Quantum Mechanics from ground zero?"
] | [
false
] | I am interested and would like to know what I need to learn in order to grasp the concepts. What do I need to learn to build my way up to get to the main topic? | [
"start taking physics classes"
] | [
"You'll need introductory mechanics (to learn basic physical laws) and Electricity and Magnetism (to learn about waves). You'll need calculus and basic linear algebra to deal with the technical details."
] | [
"Depends on what you mean by \"grasp the concepts.\" If you're just looking for an advanced layman's understanding of the then concepts I recommend John Gribbin's books \"In Search of Schrödinger's Cat\" and his followup \"Schrodinger's Kittens and the Search for Reality.\" The other route is the scholastic one r... |
[
"What is the difference between different types of plastics in terms of recyclability? Why can some types be recycled and others can't?"
] | [
false
] | Bonus points for anyone that can explain this and also explain the numbers on the bottoms of plastic containers for recycling. | [
"There are two types of plastics, thermoset and thermoplastic. Thermoplastic means that it melts like glass and can be re-formed and re-used (in a limited sense, see below). Thermoset plastics are chemically crosslinked for greater strength, and they don't melt, they burn. Thermosets can't be re-moulded, and so the... | [
"Technically, all plastics are recyclable, but in the real world it's more complicated.",
"Things like processing costs (heating, molding, etc), and the availability of a market for the recycled plastic all play a role in whether a given type of plastic will be accepted by a recycling center.",
"Different polym... | [
"u/News_of_Entwives",
" has a good point about thermosets vs. thermoplastics. ",
"All of the plastics that bear recycling symbols are thermoplastics, meaning that their shape is kinetically frozen either by the presence of crystallinity, or by being in their glassy state at operating temperature. Repeatedly h... |
[
"Why rocket engine \"exhaust pipe\" is shaped like a bell rather than a nozzle?"
] | [
false
] | If you have a nozzle shape, the gass exiting will result in higher exhaust velocity, giving higher impulse. Then why they use bell - like form? Edit: typo | [
"It has to do with the behavior of subsonic vs. supersonic flow. You are right that subsonic flow will increase in gas speed as you narrow down a nozzle, but this is only true up until the speed reaches Mach 1. At that point, the flow is said to be \"choked\" and you can't increase the speed. This is because subson... | [
"The exhaust speed is independent of the rocket speed, and should be fairly constant so a variable nozzle would have very limited applications."
] | [
"It's not just their smartness you should appreciate, but also their determination, tenacity, and utter lack of fear. Rocket engines today still are hit-and-miss affairs. Imagine how they were 50 years ago.",
"One of my favourite reads is Ignition! by John Drury Clark. You can find PDFs of it online. It's... yeah... |
[
"What is located in the area that would otherwise be a uterus if a man were a woman?"
] | [
false
] | Do men simply have larger organs/bladder? It seems like the uterus is quite a large organ in itself so I am wondering what the equivalent body area in men contains. | [
"The base of the penis is where the vagina would be, the prostate is roughly where the cervix would be and the bladder is where the body of the uterus would be (the male bladder is larger).",
"The non pregnant uterus is not that big, about the size of a clenched fist."
] | [
"The uterus is approximately the size of a very small pear (or a woman's fist) when there is nothing in it. (It expands up to 100x it's normal size to accommodate a fetus.) The uterus is located behind the bladder and in front of the rectum, so one could speculate that a male's larger excretory organs would \"tak... | [
"Thanks coolguy"
] |
[
"How do computers/digitizer watches know how long a second is?"
] | [
false
] | I assume computers/digital watches/stopwatches calculate time by "knowing" that there's 24 hrs in a day, 60 minutes to an hour, 60 seconds in a minute. If that's correct, how do those devices know how long a second is? Edit: on mobile, can't fix autocorrect in title, meant to say digital watch not digitizer | [
"Computers and digital watches use a quartz crystal as a source of their timekeeping. When cut in the right way and subjected to a voltage, quartz crystals can work as an oscillator, generating a signal at a specific frequency.",
"Since the frequency is known beforehand (as the crystal is designed specifically to... | [
"The hardware clock in modern machines still matters. There's still a battery, and the time will be lost if it dies. I'm not aware of any BIOS that uses NTP. That sync is only done within the operating system. "
] | [
"Piezo-electricity.",
"Quartz crystals are piezo-electric, which means that when they deform they produce a charge and when subjected to a charge they can deform. Quartz timing devices have a teeny tiny piece of quartz that is shaped into a tuning fork, tuned to a frequency of 32768 Hz. This is comfortably outsid... |
[
"Is it possible to identify whether a photo is sunrise or sunset without knowing where it was taken?"
] | [
false
] | Is there any kind of identifiable chromatic difference between sunrise and sunset that can be read in a photograph? For example, I would guess that sunrise would be a tiny bit blue shifted while sunset would be red shifted (I'm well aware that's not why sunsets are red!) But would these differences be overwhelmed by th... | [
"Sunsets would tend to have more color because there is more pollution in the air. This can help if comparing photos."
] | [
"I think it's funny that educators \"forbid\" students from using wikipedia. The right way to teach is to teach kids to use wikipedia as a starting point, but then to always cross-check and verify references. In that manner, it's a fantastic teaching tool."
] | [
"Sunsets would tend to have more color because there is more pollution in the air. ",
"I'm unsure that this is necessarily true - I've not seen anything that suggests air pollution is time dependent (greater in the evenings than mornings). Can you provide a source for this?"
] |
[
"How is it that all computer code is not effectively \"open source\", since binaries can be read?"
] | [
false
] | Computer code is usually written in a "higher-level" language such as C and compiled into the binary machine language that computers actually understand. This machine code can presumably be read by anyone with the know-how and access to the machine running it. If that is the case, couldn't all software be de-compiled b... | [
"Technically, one could use a decompiler to obtain the higher-level source code of an application in some form. However, this process has a number of caveats.",
"First, modern compilers can apply a number of optimization techniques that modify the code as it was originally written in the compilation process. When... | [
"The big advantage of open source software isn't that one is technically able to see and modify the source code, but that one is freely allowed to do so.",
"This is something that should be emphasized more. I wonder how a world where you could freely modify any source code, and the only problem would be to get yo... | [
"Not precisely correct.",
"You can freely modify any code you like. Closed, or Open or Free.",
"Whether you'd run afowl of copyright law if you wanted to distribute it is the real difference between the Closed and Open or Free (ethics is the difference between Open and Free)."
] |
[
"What is a \"finite\" Reynold number flow? As opposed to infinite?"
] | [
false
] | This is in a paper I am reading. I understand that Reynold number is directly correlated with turbulence, so would an infinite Reynold number just mean something is infinitely turbulent? This seems pointless to say, since turbulence can't be infinite, correct? Thanks. I am flairing as Physics, but the paper I am readin... | [
"[Physics] is fine for your flair, though if there were a [Fluid Dynamics] flair it would be even better.",
"/u/RobusEtCeleritas",
" answer is pretty close, but it's missing what it really means in context of the paper you're reading.",
"Reynolds number Re = (density*velocity*diameter) / viscosity, and is a r... | [
"you can have solutions to the Navier-Stokes equations with arbitrarily high Rn-numbers that are perfectly smooth, but they only work because there are no \"imperfections\". Once a seed of instability is planted, by statistical necessity, you will get turbulence."
] | [
"Actually that would not be a zero Reynolds number, as the derivation of Reynolds number has viscosity in the denominator that would be be an infinite Reynolds number, or perfectly inviscid flow. Re=0 is for the case when viscous effects are ",
" larger than inertial effects. It causes some weird and counter-in... |
[
"If you watch a gif of a coin flipping (without ever seeing it) to make a decision, is it still a 50/50 chance, even though the video already predetermines what side the coin will flip onto?"
] | [
false
] | null | [
"There are multiple ways to interpret probabilities. The way you're probably most familiar with is to consider them ",
".",
"That means that if you have a fair coin (p = 1/2), you can say that in the limit as the number of flips goes to infinity, the fraction of results which give heads approaches 1/2.",
"But... | [
"Also, the first interpretation is known as ",
"frequentist probability",
", and the second as ",
"Bayesian probability",
"."
] | [
"No. With Bayesian probability, there is only one outcome that is actually true. The coin either did or did not land on heads. Or if we're betting on a coin that we haven't flipped yet, either it will or it will not. The quantum physics version of this is called ",
"hidden variable theory",
". However, this was... |
[
"I came across a statistic that said nuclear energy has 0.04 deaths per TWA, whereas coal (global average) is 100."
] | [
false
] | Can anyone shed some light here? This article explains in laymans that it is reasonable to assume 30,000 fatal cancers occurred due to Chernobyl | [
"Working in a coal mine is not fun, especially in China. Oil rigs are no vacation either although being an order of magnitude safer ."
] | [
"Nuclear energy is pretty safe, despite the tragedies that happened in the 70's and 80's. There are almost 400 nuclear plants in operation now, and deaths are pretty uncommon in the nuclear power industry. Radiation exposure is a very low risk for the entire process, from mining ore through power production (alth... | [
"The UNSCEAR report claims Fukushima will likely result in a maximum increase in cancer risk to those involved by 0.02%. Normal cancer risks are between 30 and 40 % based on region and a number of other factors. ",
"Just adding some information. "
] |
[
"What would a monopole look like?"
] | [
false
] | From what I understand, monopoles are generally believed to exist, they're only so spread apart that we simply haven't observed any yet. Theoretically, what would one look like? What would it be, exactly? How would it function? Do the theories that predict the existence of monopoles actually predict how many there ough... | [
"It would be ",
" massive, on the order of the GUT or even the Planck scale. A monopole is formed at the temperature of the GUT (grand unification) and is, like all topological defects, sort of a knot in the fields. As temperature cools, the fields outside cool and create the world we know. However the knot canno... | [
"Just like normal matter, monopoles have a gravitational effect that works for the contraction of space. Considering how massive they are, if they were too dense this effect would be so big as to not allow the history of the evolution of the size of the Universe as we know it, and you end up with a Big Crunch in th... | [
"and I really wish there was, but proton decay seems to suggest there isn't",
"How does proton decay, a phenomenon we have yet to observe, suggest there is nothing fundamentally wrong with how we think about GUTs?"
] |
[
"Do LED lightbulb work in extreme cold temperatures?"
] | [
false
] | I could not find a definitive answer whether they can be used for outdoor lighting. By extreme cold, it would down to -40F. | [
"The operating temperature of the LED will depend on the design of the device, typically -40F is at or below the lower limit of silicon devices, (this will generally be shown on the device datasheet).\nLithonia Lighting OFLR 6 MO 's datasheet quotes its minimum ambient temp as -40C."
] | [
"In terms of device physics, it should keep working until it gets to more than -100C. But I'm assuming that because of the mix of different materials and the different thermal expansions the device will most likely crack or break in those temperatures."
] | [
"Thank you for the reponse.",
"The product packaging says it can withstand -25C, though I don't see that mentioned on the ",
"datasheet",
".",
"My friendly neighbourhood Home Depot guy told me it should work as long as the outdoor fixture is covered. In extreme cases, the temperature could reach -40C, which... |
[
"in the United States most northern states use substantial quantities of salt to de-ice roads and walkways; what impact does this have on the surrounding environment?"
] | [
false
] | null | [
"Geochemist from Minnesota:",
"It has an effect, but since much of the salt is only washed away when the snow melts the majority of it ends up in the storm water drainage systems. This system is designed to take water that is contaminated with all types of road/yard chemicals and keep them out of sensitive waters... | [
"The salt runoff from highways could easily kill terrestrial plants, which can be very sensitive to salinity. "
] | [
"So what happens when you \"salt the earth\" to prevent crops from growing?"
] |
[
"Why do so many illnesses relate to the throat? A sore throat/cough seems far and away the most common symptom of illnesses."
] | [
false
] | I understand that the cold heavily skews our perception of symptoms. I don’t meant most common symptom among people, but among different illnesses. | [
"My best answer would be that it's because it's the easiest way for normal people to get exposed to pathogens. Your skin provides a great barrier and is pretty immune to infection unless you get a cut, which is relatively rare. Most people don't touch their eyes too much either, making that a harder place to be att... | [
"Good question. I looked up \"pathology of sore throat\" and got a couple interesting answers\n",
"Here's one",
"Doesn't draw any huge conclusions - says \"neurogenic inflammation\" which is to say that it's just irritated and the body is producing inflammation, which can be painful. They note that the combinat... | [
"What about sore throat with no coughing? Thanks for your contribution by the way."
] |
[
"Ask Science: After just reading about the most massive galaxy cluster discovered I have a question about dark matter."
] | [
false
] | "The newfound cluster, called SPT-CL J0546-5345, is about 7 billion light-years from Earth, meaning that its light has taken that long to reach us. Thus, astronomers are seeing this clump as it was 7 billion years ago. By now, , researchers said." This statement I emboldened got me thinking... If gravity propagated ins... | [
"I'm not sure I understand your question, but the discrepency that lead to postulation of dark matter is that when we measure how fast stars are rotating relative to their galaxy, and compare that to how much mass there is based on the number of stars (mass to light ratio), we see that the stars are rotating faster... | [
"I guess my question is more:",
"If gravity was instantaneous, how much would our picture of an observed galaxy be distorted while the light was on its way here? ",
"From what I gather, what we know is that the picture we're taking is an exact representation of the galaxy if it were observed as many years ago a... | [
"how can it be still propagating unless expansion was so many multiples of the speed of light that its only reaching us now.",
"Anywhere the universe's overall expansion approaches the speed of light (with respect to our position), this means we aren't able to see past it. There is a horizon effect in cosmology t... |
[
"Is there a difference between Human embryonic stem cells and stem cells harvested by other means? If so, what are the differences?"
] | [
false
] | null | [
"Embryonic stem (ES) cells are derived from an embryo at the 64-cell stage (very early, only a short time after fertilization), and have the potential to make any cell type in the body.",
"When people talk about \"stem cells\" more generally, they are usually talking about more \"committed\" kinds of stem cells t... | [
"To expand, embryonic stem cells are considered ",
" in that they can become any other cell in the body (makes sense; the embryo must be capable of forming a whole person). Adult stem cells, i.e. those taken from a mature human are only ",
" in that they can only become ",
" types of cells. As ",
"/u/mollie... | [
"No one calls stem cells omnipotent. The correct term is totipotent.",
"Though the meanings of the roots are similar, omnipotent means all-powerful, while totipotent means whole-capable.",
"http://en.wikipedia.org/wiki/Cell_potency"
] |
[
"Are there benefits to making someone with a phobia face their fears (i.e. to help them \"get over it\")?"
] | [
false
] | null | [
"This question borders on medical advice and is therefore not allowed per our rules and reddits TOS. "
] | [
"Yeah... I couldn't think of where else to put it"
] | [
"The only suggestion I can give is that you consider seeking professional advice because I don't think the internet can help too much here. If you are curious about treating phobias in general, submit a post that does not refer to you or anyone personally and simply asking if making people face their fears is a goo... |
[
"How far above the earth must one go before compasses stop working."
] | [
false
] | [deleted] | [
"It depends on how sensitive the compass (or magnetometer) is. But basically, the strength of the magnetic field decays as 1/d",
" where L is the various components of the magnetic field. ",
"L=1 is the dipole component (the one with north and south poles), which dominates the surface partially because the stre... | [
"It depends on where you are with respect to the sun. Magnetic fields extend infinitely, though they decay according to a power law with distance from the source. At some point, interplanetary magnetism, due in large part to charged solar particles, overcomes our own field. Magnetic storms inside the Earth's magnet... | [
"McBented specifically said:",
"If your compass/magnetometer has infinite sensitivity, it would stop working when it is outside earth's the magnetosphere",
"Which is false. With infinite sensitivity it would stop working at the speed of light multiplied by the time since the last time the poles flipped (assumi... |
[
"Onion, tobacco, baking soda, and pennies?"
] | [
false
] | null | [
"Wasp stings are alkaline. Vinegar or other weak acids such as coke (citric/phosphoric acid) relieve the pain by neutralisation.",
"Edit: Just to note, this is the purported reason that these remedies are mentioned for. Whether they actually work, due to more complicated factors such as multiple compounds produci... | [
"I'm intrigued by the baking soda - as it's alkaline. In some ways one would think it would actually make things worse?"
] | [
"Possibly just a confusion with bee stings, which are acidic (pH 4.5-5.5). Although they also contain some basic compounds in the sting as well, just to be awkward. "
] |
[
"If an electron goes around the nucleus in a \"probability cloud\" and that the electron disappears and reappears in existence, does it mean that the electron appears at infinite positions around the atom or does it just orbit the atom? Also why does the electron not fall into the nucleus?"
] | [
false
] | null | [
"the electron disappears and reappears in existence",
"I'm afraid I don't know what you mean by this. An electron in an atom just sits there.",
"does it mean that the electron appears at infinite positions around the atom or does it \njust orbit the atom? ",
"It means that electrons aren't particles and they'... | [
"Stationary in the sense that their properties do not change over time, but not in the sense that it has a single definable position.",
"In a classical model with a discrete electron orbiting a nucleus, you'd expect that certain properties like position to change in a regular, predictable way depending on the mom... | [
"but an electron can act like a particle... ",
"wave-particle duality is in reference to measurement. Without measurement quantum mechanics is 100% a deterministic theory of quantum wavefunctions whose dynamics are governed by a complex (as in imaginary and real components, not as in \"complicated\") heat diffusi... |
[
"How fast are our brain commands? Not our reaction time but the actual command of your brain commanding your finger to move."
] | [
false
] | I want to lift my finger the time it takes for my brain to tell my finger to move how fast is that? Has the speed been defined and what does the speed compare to? Edit: Is brain command speed set and cannot be improved? Also the other way around can it be slowed? | [
"Well, you kind of have to take into account the reason the finger is moving, many reflexes don't actually pass through the brain before a response is generated, which obviously helps speed things up."
] | [
"Not all that fast.",
" Different sources will put it at a different speed, but it depends on the nerve in question and is never faster than about 200mph. This isn't actually surprising, as nerve impulses depend on chemistry within (and between) the nerve cells."
] | [
"Yes, you are. It does seem instant :)",
"The nerve cells pass impulses between one another chemically--one neuron releases a chemical called a neurotransmitter, which then binds to another neuron and passes the signal along (very oversimplified explanation, but this isn't really my area of expertise). The releas... |
[
"How far would I get if I skydived with a wingsuit on Jupiter?"
] | [
false
] | On earth, I have read the average ratio of horizontal movement to vertical drop is ~2.5m/1m. I am interested in Jupiter because of the different density of the atmosphere, the much greater potential height drop, and the more intense gravity. Ignore the extra weight of any breathing apparatus that would be needed. Pleas... | [
"This entire post is at best, a guess. An educated guess, but still a guess.",
"Jupiter has a mean density of 1.326 g/cm",
" which is close to the density of air. This suggests that there is no rocky core, or if it ever had one it evaporated away. The Juno spacecraft is on it's way right now to help answer this... | [
"this is absolutely not true, in any way whatsoever. An MRI produces magnetic fields several thousand times the strength of Jupiter's, and that hasn't 'fried' anyone yet. ",
"In all seriousness, did you just make this up completely out of your asshole?"
] | [
"Jupiter's interior is approx 71% H, 24% He and 5% \"other\". Of course, since Jupiter is so big this leaves about 16 Earths worth of heavy elements. We literally don't know what that means, gravitational measurements aren't good enough to rule a solid core entirely, and there is no real way to tell how big it is i... |
[
"How can ice cream bend a stainless steel spoon?"
] | [
false
] | null | [
"So first off, Stainless Steel isn't a specific material. It's an entire class of materials with a huge range of properties. The type typically used in basic utensils is Austenitic, which is an entire sub-class and though it offers excellent rust and pitting protection, it's mechanically the weakest, in terms of ha... | [
"Is that why ice cream scoops have such thick handles?"
] | [
"I can't speak for the ice cream scoop manufacturing industry but I'd hazard a guess that that's a good bet for why. That is, the combination of bending, narrow cross-section, significant torque from the long handle, and the relative stiffness of ice cream all put together."
] |
[
"Is there an experiment that could cause a Vacuum Metastability Event if the universe is indeed in a false vacuum state?"
] | [
false
] | Would this require some kind of super energetic explosion? Is it possible that the LHC could do something that we are unaware of that would cause such an event to occur? Could the universe constantly be experiencing a "VME" yet we are unaware because MWT is true? | [
"In the last few months there has been active discussion on whether or not this is even possible, in principle, if we life in a nearly Minkowski space.",
"In MWT (or string landscape), the vacua are really degenerate. In this case all the Hilbert spaces are orthonormal and it's really impossible to know about the... | [
"Probably not, there are energetic events throughout the universe that are far more energetic than we could ever produce, gamma ray bursts being a good example."
] | [
"even if we knew of such an experiment, it might not be a good idea to perform it. i'm reminded of kurt vonnegut's tralfamadorians accidently blowing up the universe. "
] |
[
"Why do you need vitamin D to metabolise calcium and other minerals?"
] | [
false
] | I've heard one of the best ways to die slowly is to deprive yourself of sunlight for a long time. You end up with low testosterone, thinning hair, weight (fat) gain, increased risk of osteoporosis, heart problems, poor sleep from abnormal circadian rhythm, increased risk of diabetes, no libido, depression…it's horrible... | [
"Yay! A chance to use my degree!",
"In Short: Vitamin D plays a major and complex role in the conversion and transportation of calcium and cholesterol in the body. Like incredibly complex. Because vitamin D is essential in transforming calcium into a form that is easy to transport/use, without Vitamin D you can n... | [
"Current M.S. in Human Physiology student here so I'll do my best with you're question. The bottom line is that Vitamin D is a precursor for a hormone called Calcitriol (Vitamin D3). Calcitriol acts on the small intestine to promote calcium and phosphate reabsorption and acts on bone tissue to promote calcium and p... | [
"Vitamin D is important for covering tryptophan in serotonin in the brain. Serotonin, in turn, is important for emotions, impulse control, and executive functions, among other things. ",
"Source: Patrick & Ames (2015)"
] |
[
"How do carcinogens work at the cell level?"
] | [
false
] | Question in title. Lets say I drink water from plastic bottles with bpa in them. Or I consume a product with carcinogenic properties (burnt food/ teflon/ etc). My understanding is that most cancer is a growth resulting from cells multiplying too quickly, improperly, with a mutation or out of control. At the cellular le... | [
"Firstly, bisphenol-A is classified as an endocrine disruptor (estrogen-mimicking, I believe). ",
"Now, carcinogenesis is an extremely complex process, and my answer could be pages, so I'll try to be pithy.",
"You are correct that tumors result from uncontrolled cellular division. Normal cells usually have ge... | [
"This is an excellent answer. I think the key point is that the process of carcinogenesis is very complex and multifaceted, there being multiple biochemical mechanisms by which it can occur."
] | [
"Just to add, the effects of BPA aren't completely characterized as estrogen mimicking. Some studies.show that it may be involved in the synthesis of estrogen or affects downstream targets of estrogen mediated signaling.",
"But it is definitely an endocrine disruptor. "
] |
[
"Would it be possible to make a generator that runs on chemical energy from food or organic material?"
] | [
false
] | null | [
"Ah. Such questions are better suited for our newish sistersub ",
"/r/asksciencediscussion",
". Please post there instead."
] | [
"Like ",
"biodiesel",
"?"
] | [
"Sort of, but I was thinking more along the lines of throwing literal foodstuffs into a stomach like generator and getting ATP or some other charged chemical battery as an output, almost like a living power generator. "
] |
[
"Why can't assistance softwares (Google, Siri, Cortana) speak 'normally'? What hurdle is holding them back?"
] | [
false
] | null | [
"when you speak you use pace and emphasis to help convey meaning, rather than saying each word in a neutral tone like Siri does. The problem is you do this in an incredibly complex way that takes into account the context of every word, sentence, and situation. There is research being done both on this and on using ... | [
"Pretty much this. Trying to figure out exactly how to pronounce a phrase is very context-dependent, which is something that humans can do subconsciously but computers cannot. Take a question, for example. If you know that the sentence you're about to say is framed as a question (i.e. it has a question mark at the ... | [
"I watched a video of the woman who did Siri's (Australian) voice and she mentioned that she (mostly I believe) recorded syllables. SO when Google or Apple added a new word they wouldn't need to call the the person the voice each individual word. This is why I think it doesn't sound 'normal'."
] |
[
"How can the size of the known universe be increased?"
] | [
false
] | Is it a matter of simply observing something more than x-light years away? Is there a point where it simply becomes harder to view things further and further away simply because the stars (and other astronomical objects) closer to us simply block our view? Thank you for any thoughtful replies. | [
"Sure. That happens all the time. Here is ",
"object UDFj-39546284",
" which has a redshift of about 10.3 which corresponds to a comoving distance of 31.7 billion light years. To paraphrase RRC, if you were God and could pause the universe and get out a tape measure, this object right now would be 31.7 billi... | [
"The first. Since there is a finite speed that light or anything carrying \"information\" can travel, and there's a finite age of the universe, then there's only a finite distance we can observe. ",
"edit: there are some regions that are partially blocked from view by our own galaxy and whatnot, but that's not ex... | [
"Since the Universe is constantly expanding, would it ever be possible to detect objects that are at a far enough distance that the light originating from them is older than the Universe? ",
"Let me phrase that better: would it ever be possible to detect objects at (x) lightyears away if the Universe were (<x) ye... |
[
"Skin on my tomato soup?"
] | [
false
] | Google was surprisingly un-helpful. Maybe my search terms were off, but I kept getting recipes and the like. My question is: Why does tomato soup get a "skin" as it cools off? | [
"According to ",
", oils and the proteins from the meats, veg or dairy products used during the cooking process thicken the top of the soup.",
"Just cover it as soon as you can, or:\n",
"How to stop skin forming on soup"
] | [
"Think about the soup-air interface. For hot soup in relatively drier air, moisture will evaporate at the interface, leaving a region on the surface that is enriched in all the non-volatile compounds. Any of those compounds that are not very soluble in water may experience local supersaturation and precipitate ou... | [
"You can also just skim it off with a spoon - I've done this many times with the skin that forms on milk if you microwave it."
] |
[
"Why are resistors so strangely incremented?"
] | [
false
] | I do not have a strong background in electronics/EE But have been diving into it. It just seems going by factors of ten would be easier? | [
"Resistors come in different tolerances, generally 1%, 5%, 10%, or 20%. The incremental values are based on the tolerance. For example 10% increments starting at 100 ohms would be 100, 110, 121, 133.1, etc. You can sort of see how some seemingly unusual values are arrived at. "
] | [
"It is possible to find resistors in almost any value. Some might be specialty or uncommon values, but you can get almost value you may need. For example, check out some of the resistors you can get from ",
"digikey",
" and scroll through the values options. (This is only chassis-mount. Other configurations off... | [
"The values are based on a logarithmic scale, that is the percentage difference from one value to the next will be approximately constant. For example in the ",
"E24",
" series, each value is about 10% higher than the previous value."
] |
[
"Can a photon achieve a stable orbit around a body of mass?"
] | [
false
] | null | [
"In theory yes, in practice no. Normally mass in orbit has the ability to slow down and speed up, and this enables objects to be in non-perfectly circular orbits. A photon could theoretically be in an orbit around a black hole. However, because any real-world black hole will have some spin there is only one precise... | [
"In theory yes",
"No, not even in theory.",
"You're talking about the photon sphere.",
"http://en.wikipedia.org/wiki/Photon_sphere",
"But orbits of the photons in a photon sphere are unstable even theoretically:",
"http://www.physics.nus.edu.sg/~phyteoe/kerr/paper.pdf",
"The paper focuses on the Kerr so... | [
"This is called the photon \"sphere\" around a black hole (it is only spherical around a nonspinning BH, but there are still photon orbits around a Kerr (spinning) BH). However, the orbits are not stable: any infinitesimal perturbation will send the photon out to infinity or plunging into the BH."
] |
[
"Do \"non-water rainbows\" exist and (if yes) what do they look like?"
] | [
false
] | I've been thinking about rainbows from other liquids than water (e.g. gasoline) and wether they'd look like regular ones | [
"The main difference between different liquids boils down to their indices of refraction and their dispersion. Changes in the index of refraction would alter the size of the rainbow arc, while changes in their dispersion would change how wide the actual rainbow band is. If the dispersion is negative, it would also ... | [
"Do you have any examples?"
] | [
"It should work with any liquid, and clear helps. As for example it's hard to find, you need to spray a large amount outside in the sun. Everything I can think of is quite dangerous to do that (alcohol, acetone, gasoline, oils). Everything else is water based that I can think of so I can't find pictures of any wate... |
[
"why can cold temps and sugar cause tooth pain?"
] | [
false
] | I know it's somewhat common, to have sensitive teeth (I should probably just go buy some sensodyne..) but I'm curious as to what's actually happening. Why is it that when I eat something like a gummy bear, or drink very very cold drinks, my teeth are in a lot of pain? What kind of reactions are going on that causes thi... | [
"Your teeth have had their enamel worn down exposing dentin tubules. These little tubules go to inside of the tooth where the nerves are located. Pressure changes due cold water in the tubules can cause pain because of the interaction with the nerves. Not exactly sure why sugar causes pain too unless it has to do w... | [
"I'd say that was a tangential question, why do my teeth hurt sometimes with sugar but not other times with the same foods?"
] | [
"I have this problem with sugar, and it's completely random, sometimes a snickers bar hurts my teeth other times it doesn't. it would be great to have an answer."
] |
[
"Why do we tense up before impacts?"
] | [
false
] | I'm not talking about putting your arms up to brace a fall-- I'm talking about the feeling where every muscle in your body tenses up before an impact, like a car accident. Evidence has shown that this action increases injuries and deaths; this is why, for example, drunk drivers are less likely to be killed in a head-o... | [
"Hold out your arm.\nNow touch your humerus. Try to get in there and pretend like you are really trying to touch the bone.\nNow, flex your biceps, and repeat.\nWhich hurts more?\nBasically, bone > muscle; muscle = protection/strength"
] | [
"Flight or fight response. Tense muscles produce movement more quickly from brain signals than relaxed muscles. Relaxed muscles allow the force of the impact to be applied to a greater area on the body, which reduces trauma to just one part of the body. Yes, high velocity collisions where tense muscles were not ... | [
"I believe it's an instinctual response which protects your bones & joints by having your muscles absorb the force of impact.",
"If your muscles are relaxed (loose), the force of impact is absorbed by tighter or more resistive structures, like bone & ligament. If you put tension onto your muscles, they will abso... |
[
"If the pressure at the entrance and exit of an electric fan remains constant, is the exit temperature still higher than the entrance temperature?"
] | [
false
] | I know fans normally heat up air, but if it were possible to maintain the same pressure at the entrance and exit of the fan, would the temperature remain the same, or would the exit temperature be slightly higher? (Assume air is an ideal gas for simplicity.) | [
"The pressure wouldn't be the same at the entrance and exit or the air wouldn't move (and therefore it would be a really lousy fan)",
"A fan will create a slight vacuum on the entrance side and a slight pressurization on the exit side. "
] | [
"The fan heats up the air because the motor and the blades are not 100% efficient, and because the fan does work on the air, increasing its enthalpy. This is more significant than any effects from pressure alone (for a typical system involving a fan).",
"It also depends heavily on whether or not the motor is in ... | [
"I'm interested in this also.",
"Although assuming pressure and temperature are directly related I'd assume = Pressure means = Temperature?"
] |
[
"At what point in time does a laser become deadly?"
] | [
false
] | So if you were to super charge a laser pointer, either by more power or a new way to project the laser, when would it be strong enough to burn through someone or burn them in general | [
"2-5 milliwatts, laser pointer up through light source.",
"50 milliwatts or more, burn skin and flammables.",
"500 milliwatts or more, industrial cutting or weapons grade."
] | [
"LaserHorse has accurately answered the question of power. OP asked \"At what point in time does a laser become deadly?\" The answer for a > 500mW laser is: when you turn it on."
] | [
"We do. There is currently a commercially available 1000mW hand held lasers for $200.",
"Lasers make horrible weapons compared to projectile weapons. They deliver far less energy and are much harder to handle. You're more likely to permanently blind yourself than kill someone else when you use one. All it takes i... |
[
"What is the most inefficient thing that our bodies do?"
] | [
false
] | null | [
"Our breathing is inefficient...Air contains about 21% oxygen, and the average breathe exhale contains about 17% oxygen. Now granted, this makes things like CPR work, since we breathe out, into the victim, air that contains enough oxygen for them, but it still could be considered inefficient.",
"BTW, this also ... | [
"Well, remember that the actual transfer of gases relies on diffusion. That means from an energetics standpoint, it's basically free. Our blood cells do not need to expend any energy to exchange gases. The flipside of this is that it means there is a hard cap on how much you exchange - the concentration of oxygen i... | [
"This, an excess of vitamins within the blood can be just as dangerous as too little so the body needs an effective way to remove them.",
"Anaerobic respiration is something we don't always have a choice about performing, depending on circumstances, but it's highly ineffecient."
] |
[
"Velocity is to Speed as Acceleration is to... what?"
] | [
false
] | null | [
"There's no single word. It would just be called \"the magnitude of the acceleration\"."
] | [
"It's not quite the magnitude of the acceleration, though. For example, orbiting planets' change of speed is ~0, but they are accelerating."
] | [
"That's different than what's in the title.",
"The speed is to the velocity as the magnitude of the acceleration is to the acceleration. Because the speed is the magnitude of the velocity.",
"The ",
" is a different thing, which is ",
" the magnitude of the acceleration, and also doesn't have a specific nam... |
[
"What happens when a a radioactive bunch of atoms reach their last atom? (Half life question)"
] | [
false
] | [deleted] | [
"For one atom, after the half life time has elapsed, there is a 50 percent chance it has decayed."
] | [
"Yes."
] | [
"So eventually it will have decayed, just not necessarily on the first or second half life time being up?"
] |
[
"Is it possible to make gunpowder with an alternative to potassium nitrate?"
] | [
false
] | I heard that the recipe for gunpowder is charcoal, sulfur, and potassium nitrate to act as the oxidizer. Is it possible to make gunpowder with another oxidizer? Would it work well? | [
"Sodium nitrate gunpowders",
" are also possible and saw some historical use, but sodium nitrate is strongly hygroscopic - it loves to absorb moisture from the air. This is inconvenient if you want to keep your powder dry. Chemically it's not hard to turn sodium nitrate into potassium nitrate, if you have access ... | [
"I’m not an expert in this type of chemistry, but I’m pretty sure this is wrong. ",
"Metallic potassium (in its 0 oxidation state) is highly water reactive, but in salts such as KNO3 potassium is present as K+. This is the same thing as saying table salt is dangerous because Na(0) is explosive and Cl(0) is poison... | [
"Strictly speaking a catalyst is not consumed by the reaction it catalyzes, and NO3 is very clearly consumed by the reaction"
] |
[
"Why is the Sin 0i/Sin 0r ratio is equal to the refractive index of a material?"
] | [
false
] | Hi, I was covering sine's law in my science class and could not figure out how this ratio is equal to the refractive index. Thank you! | [
"This only works if the index of refraction in the material where the incident beam travels is 1 (which would be the case, to very good accuracy, if the incident beam is traveling in air). You can see this via Snell's Law."
] | [
"Thank you so much "
] | [
"Snell's law is a consequences of Fermat's principle: ",
"https://en.m.wikipedia.org/wiki/Fermat%27s_principle"
] |
[
"Are there any \"weird\" uses for heavy/transuranic elements?"
] | [
false
] | I recently came across the fact that Americium is used in smoke detectors . Are there any other interesting applications of other heavy elements? | [
"Curium [Cm - 96] is used in X-Ray Spectrometers as an alpha particle emitter. Mars Rovers (among others) used this tool. It was also used a a fuel for thermoelectric generators in other spacecraft. So not much really interesting \"everyday\" stuff.",
"Californium [Cf - 252] is a powerful neutron emitter. So ... | [
"Depleted uranium (mostly U-238) has been used for tank armor, armor piercing rounds, etc because it is extremely dense (~19 times denser than water, 2.5 times denser than steel IIRC).",
"Another user mentioned curium for RTGs. Pu-238 is what is used in RTGs for space missions; both this and curium have a high sp... | [
"Uranium itself had uses within fluorescent glass. They're definitely ",
"beautiful",
" although they are less common today for food. You still find it used for green fluorescence standards for calibration though.",
"Also fiestaware used to use a different uranium compound as a glaze. Not so much anymore."
] |
[
"If proteins are denatured in the stomach, how does the protein \"gluten\" trigger an auto-immune response in the intestines of individuals with Celiac disease?"
] | [
false
] | If proteins are denatured in the stomach, how does the protein gluten trigger an auto-immune response in the intestines of individuals with Celiac disease? In other words, how and why does an organism's auto-immune response occur in the presence of the "protein" gluten after its denaturation? | [
"It isn't the full gluten protein that invokes an immune response for those who suffer from celiac disease. Several peptide fragments as a result of enzymatic hydrolysis of gluten invoke an immune response leading to inflammation and other nasty effects in those individuals. ",
"Here is a decent article about it ... | [
"The underlying mechanism of gluten sensitivity in the gut is not very well-known. However, some people hypothesise that the intact protein (or intact peptides which make it up) can bind sugars displayed on intestinal cells. The cells use these sugars for cell-cell communication and identification, but gluten (and ... | [
"Also, gluten is really difficult to hydrolyse, so even after being exposed to your stomach acid a significant portion of it remains intact when it reaches your intestines."
] |
[
"What kind of spider is this? Sorry for the blur, I was trembling. (Western Pennsylvania) Thanks!"
] | [
false
] | [deleted] | [
"Submit it to ",
"r/whatsthisbug",
", they'll know for sure."
] | [
"TIL ^"
] | [
"Excellent. Thanks."
] |
[
"Do orbital physics mean that dog fights in space are impossible?"
] | [
false
] | I was wondering if orbital physics would prevent Star Wars-esq dog fights in space. Would the fighters or whatever not have to travel along orbital paths, meaning that the idea of manoeuvring in three dimensions becomes totally different from what we see in movies/games/books? | [
"AFAIK it's possible, given that you have ",
" powerful RCS and extremely good engines mounted basically everywhere. Oh, and you find some way around the fact that with that kind of cargo and engine power, you probably have fuel for a minute or two of flight. Basically, it's insanely hard, not quite impossible. "... | [
"I feel like it'd be less like dogfighting and more like really expensive high risk dodge ball."
] | [
"The with current propulsion technology, two ships in similar orbits would probably look more like a naval battle than a dogfight. The main difference being a 3D playing field, rather than the flat ocean.",
"To give you an idea"
] |
[
"Can you create a homogenous electromagnetic field with an elliptic cylinder?"
] | [
false
] | Almost all coils I see for electromagnets are built with a . Is it possible to achieve a similar field homogeneity through a coil wound as an elliptical cylinder instead? | [
"Using Biot-Savart to compute the field at the center of the ellipse, we get",
"B = μ",
"i/πa ",
"∫",
" sqrt(1 - k",
"sin",
"θ)dθ",
"where",
"k = sqrt(1 - a",
"/b",
")",
"where a is the semiminor axis and b is the semimajor axis. You can see that when a=b, it's a circle, so k=0 and the integr... | [
"Yes. Your intuition is correct.",
"An infinitely long elliptical cylinder will have a homogeneous field, meaning ",
" is the same everywhere within the cylinder. Circles and ellipses are not special. Any shape of cylinder will have a uniform field inside. When I say \"any shape cylinder\", I mean that the cyli... | [
"Thank you!"
] |
[
"Does light have volume or not?"
] | [
false
] | null | [
"A photon has no volume."
] | [
"My brother wants to know how something with no volume can exist in a 3 dimensional universe?"
] | [
"Elementary particles are pointlike, including the photon. They don't need volume to exist."
] |
[
"Is there any discernible difference between engines in the V formation and those that are inline?"
] | [
false
] | [deleted] | [
"I guess the performance will only be slightly different.. ",
"the biggest difference will be in the vibration, noise, size, weight, and efficiency of the engine.. However, the variables are too many to conclude an answer for your question.. for example, the angle of the V engine would also determine the outcomes... | [
"Essentially yes, all those things. The main differences are the shape, affecting where you can put the engine, and how large it is, and for performance, the torques the engine causes on the mounting, which affects vibrations. This is also affected by piston firing orders and the number of pistons.",
"Take a look... | [
"Interesting question, i'm interested in the answer. In my experience with motorcycles, the V engine configurations provide a different power delivery and a more compact vehicle is able to be created due to the layout. But i dont know how this is applied to cars since you have all that space in the front to do what... |
[
"Why does water gather together?"
] | [
false
] | When I spill water, why does it create a puddle instead of evenly dispersing? And when it starts to flow, why does it move in a little line or stream instead of just spreading in all directions? Same goes for water droplets and when water comes out of a hose. Thanks for your help! | [
"Yay finally a question I can answer!",
"Water molecules want to bond together and form hydrogen bonds between each other. This causes them to exhibit surface tension. The water molecules at the surface of the liquid don't have as many other molecules to bind to. Therefore, the surface molecules create stronger b... | [
"A great way to examine this is fill a glass up 100%. Along the rim, you'll see that the water SHOULD be spilling but surface tension keeps it from doing so."
] | [
"so are there liquids with extremely low surface tension that never form droplets or puddles?"
] |
[
"If gravity can change how fast a human is able to run, what would be optimal for us to get the highest sprinting speed?"
] | [
false
] | [deleted] | [
"It's probably already \"optimal\" since we evolved with our current gravity. Gravity doesn't necessarily mean you can run faster. It increases the force with which you are pressed against the ground, which in then allows you to press away from the ground equally hard (if you have the muscles). But since we evolved... | [
"But since we evolved within the gravitational field we're all used to, our bodies are probably already optimized to run as fast as we can.",
"No, human gaits are not optimized for speed. They are pretty close to being optimized for energy expenditure, however. This is why everyone has pretty much identical gaits... | [
"Surely the limitations have more to do with torque and stance rather than with friction (runners aren't usually in danger of slipping if they push too hard). Lower gravity would be more difficult because there isn't enough gravity to keep you upright in your normal running stance, since you don't push off the grou... |
[
"If cellular hydration is through osmosis, how do the kidneys decide what is considered waste?"
] | [
false
] | null | [
" Kidney function is an incredibly complex process. If you aren't prepared to answer in-depth, follow up questions about how kidneys work please reserve your comments for responses to other comments. Thanks a ton."
] | [
"The kidneys respond to a number of cues to determine whether to retain water or to pee it out. Blood pressure, electrolyte balance/hydration, and hormones levels (particularly anti-diuretic hormone ADH) are key factors but the system is incredibly complex"
] | [
"Yup. One of the longest, most Interesting sections of all my anatomy/physiology courses.",
"The basic, shortest answer is that your body can control osmosis indirectly. If you want to bring water into a cell or tissue, or pull water out of a solution, then use active transport to increase the concentration of s... |
[
"If our body temperatures are ~98.6 F, then why does a day with temperatures in the 90's feel hot?"
] | [
false
] | null | [
"your body constantly produces heat through various processes. You lose heat through conduction and convection. Fourier's law states that heat transfer is equal to some constant times the temperature gradient. In other words, what you are trying to send heat through and how big a difference in temperatures will det... | [
"http://www.reddit.com/r/sciencefaqs/comments/hi56t/why_do_we_feel_uncomfortably_hot_when_the_air/",
" ",
"http://www.reddit.com/r/askscience/comments/gnkvw/if_we_regulate_our_body_temperature_at_986f_why/",
" \n",
"http://www.reddit.com/r/askscience/comments/gty8o/why_is_it_that_our_core_body_temperature_i... | [
"That makes a lot of sense. Thank you!"
] |
[
"Can a binary star system have a small (Jupiter size) star orbiting a larger (Sol size) star?"
] | [
false
] | In Arthur C. Clarke turned Jupiter into a star (in his book "2010") in order to provide warmth/light to one of its moons. Can a solar system like this actually form? That is: one small star very much in orbit around a larger star similar to our own. Edit: Now this article appears that show a Saturn-size star. | [
"You can't have a star that is the same mass and radius as Jupiter orbiting a Sun-like star, simply because the \"Jupiter-star\" would not have enough mass to start nuclear fusion within its core. It would be entirely possibly to have an M-dwarf orbiting a sun-like star but these generally have masses between 0.08-... | [
"It's Saturn that's less dense than water. Jupiter has 1.33 times the density of water, which is still much less dense than Earth.",
"A red dwarf in Jupiter's orbit would probably destabilize the orbits of Saturn and Mars, but the other planets would probably be ok.",
"You could also have a brown dwarf with abo... | [
"Depends on what you mean by Jupiter size. If you mean mass, then no, an object with the mass of Jupiter will be a planet like Jupiter. You need a minimum of 75 Jupiter masses for a star.",
"If you mean diameter, then yes, the smallest red dwarf stars are similar in size to Jupiter despite being much more massive... |
[
"How are the Nazca lines so permanent?"
] | [
false
] | After hearing about this looking newly discovered Nazca drawing, I again began considering the Nazca lines as a whole. How are they so lasting? I read that all they are is displaced or depressed dirt, with a layer of differently colored soil filled into the space. How has this not been washed away, or how has the surro... | [
"The surface is made of stone, not sand, and the climate of the area is such that there is practically no erosion.",
"Edit: either Reddit is breaking or there's a lot of shadowbanned users on this sub. Keep getting notifications for comments, but when I go to check it, they're gone."
] | [
"If you think thats weird, check out Peru's \"Candelabra\".",
"In roughly 200bc someone carved out the beach sand in the shape of a candelabra, and the complete lack of erosion means thats it's still there today.",
"https://en.wikipedia.org/wiki/Paracas_Candelabra"
] | [
"Just for the sake of clarity and accuracy, relics in the area have been dated to 200BCE, but nobody is sure when it was actually carved. A number of theories posit that it is post-Colombian. It's definitely old, but 2000 years is iffy."
] |
[
"With all the talk about Ebola, im curious to how a disease starts/spawns? How does a disease just \"appear\"?"
] | [
false
] | Like the title says. How did disease such as Ebola and H1N1 start or begin? | [
"We classify \"zoonotic diseases\" as newly emerging diseases which are able to infect humans, either directly or through mutation. Zoonotic diseases include ebola, HIV, and Nipah, and are more likely to occur in areas where the populace has a high level of contact with animals or fecal matter. The animal host for ... | [
"No not quite, fecal matter is just a common route of transmission to humans. Viral and bacterial mutations happen all the time, they came from and mutate just like any other animal. Some monkey out there had SIV (simian immune virus), and one of the viruses in the monkey mutated such that it could infect humans. W... | [
"Interesting, so when an area or \"pile\" (couldn't think of a better word) of fecel matter builds up, do the germs mutate to become a disease?"
] |
[
"Is it possible to convert electric energy into nuclear potential energy?"
] | [
false
] | Nuclear fuels have incredibly high energy density, and I was wondering if it's possible to create a "nuclear battery" -- for instance, using electricity to fuse elements into fissionable fuel? Additionally, it would be interesting to get a ballpark estimate on the energy efficiency of such conversion. | [
"You can use accelerator-driven fusion reactions, where the energy is “electrical” in that it comes from some RF cavities or some other kind of accelerator, to produce fissile nuclides, and then cause the fissile nuclides to undergo induced fission. But the efficiency would be zero, for all intents and purposes.",
... | [
"Not really, cold fusion seeks to produce net nuclear energy, but the OP just wants to get back the electrical energy that was put in."
] | [
"Accelerator-based fusion is possible and routinely used in research. It doesn't release more energy than you put in, however."
] |
[
"Change in a cup - always about $25."
] | [
false
] | null | [
"When the glass is full, I take it to my bank",
"There's the issue. The cup can hold a fixed volume. Let's assume your change is randomly distributed among coin types (or that the distribution of change you get is nearly the same each time you get change). Since the coinage distribution doesn't change much, ne... | [
"I would second that question. Let's say everyday before you go to work you grab a coffee and a bagel, being that humans are pretty habitual creatures you're going to purchase the same type of bagel and coffee when you find one you like. Carry over that for the majority of your purchases and you will end up spend... | [
"I would second that question. Let's say everyday before you go to work you grab a coffee and a bagel, being that humans are pretty habitual creatures you're going to purchase the same type of bagel and coffee when you find one you like. Carry over that for the majority of your purchases and you will end up spend... |
[
"Are there any theories on different ways to generate gravity besides having mass?"
] | [
false
] | Is there any research let alone theories on different ways to generate gravity besides having a large mass? The question is mainly for its application for space and low gravity planets. | [
"You can definitely measure both centripetal and gravitational forces with an accelerometer.",
"No, you can't. From ",
"Wikipedia: Proper Acceleration",
"\"In relativity theory, ",
" (i.e., ",
") experienced by an object. It is thus acceleration relative to a free-fall, or inertial, observer who is momen... | [
"It's not ",
" gravity, but one idea for ",
" gravity (which would be useful for space ships and stations in a microgravity orbit: spin a circular disc around at a constant velocity to generate a centrifugal force, making the outside of the disc exert a normal force back on you to counteract it, thus simulatin... | [
"It seems like it wouldn't be exactly like gravity. Imagine running (or driving) around a spinning space station. If you could run fast enough, you'd get lighter and eventually start floating. In the other direction, you'd just get heavier and heavier. If the radius were small enough, jumping could cause some prett... |
[
"What would be the most optimal way to stop a hovercraft (the ones that float above the ground) going at high speeds?"
] | [
false
] | I think the closest thing to an actual hovercraft would be that bullet train on magnets Sorry if it's a stupid question but I'm curious since I don't really know much about this stuff... | [
"A bullet train actually has more braking options than a hovercraft thanks to a large, high energy magnetic field and physical tracks. A hovercraft only has two forces to slow it down (assuming you're not willing to let it slide on the ground): drag and thrust.",
"Your options for stopping a high speed hovercraf... | [
"Dropping the air cushion on a hovercraft would be the way to go about an emergency stop. Most hovercraft travel over water anyway, limiting damage to the craft bottom."
] | [
"If it's floating, then the most effective way to stop it is to provide something with a lot of thrust in the opposite direction. Hovercraft usually use propellers or ducted fans for their forward thrust, so you would just have to reverse them in some fashion to get an equal amount of \"braking\" force.",
"Hoverc... |
[
"Geography: How do these features in Southern China form?"
] | [
false
] | I found image on and found these features particularly odd in their shape and proximity. What processes could have formed them? For approximate scale, there is a power line tower on the right with which you can compare. image. | [
"Thanks. Made famous in The Man with Golden Gun and again in Heaven and Earth. And one or two ink drawings a few years before that. "
] | [
"http://en.wikipedia.org/wiki/Karst"
] | [
"So they're called Karst towers. Thanks! Upvotes for you! :)"
] |
[
"Why do CO2, CH4, H2O, etc. absorb infrared radiation while diatomic gasses such as O2 and N2 do not?"
] | [
false
] | null | [
"See the ",
"theory section of Infrared Spectroscopy",
". A change in dipole is necessary:",
"Simple diatomic molecules have only one bond and only one vibrational band. If the molecule is symmetrical, e.g. N2, the band is not observed in the IR spectrum, but only in the Raman spectrum. Asymmetrical diatomic ... | [
"Mostly correct.",
"The change is kind of an awkward way of stating it (even though it is very standard). In fact most people assume that the average upper and lower state electric dipoles are equal (though there is no rule stating that has to be true).",
"What you are really trying to say is that the molecule... | [
"In a harmonic oscillator Re does not change with vibrational excitation. Thus since the average distance does not change, the average electronic distribution does not change and the (average)electronic dipole will be exactly the same. This is obviously not exactly true for really anharmonic systems.",
"If you ... |
[
"If dark matter makes up 80% of our universe, why don't we detect its gravitational effect on our space probes?"
] | [
false
] | null | [
"Because while \"80% of our universe\" may sound like a lot, it is actually locally very small if you spread it thinly and more-or-less evenly throughout the galaxy. Furthermore, since it is spread more-or-less evenly, it pulls on our space probes in all directions, so the net force on them cancels out to zero."
] | [
"We can detect it, just not directly. The Cosmic Microwave Background provides a snapshot of the universe when it was relatively young and dense, and the irregularities in the CMB are highly sensitive to changes in the ratio of dark matter to visible matter."
] | [
"Actually, you have it backwards: Galaxies don't capture dark matter, galaxies form ",
" dark matter halos."
] |
[
"How do elements decay into other elements?"
] | [
false
] | We constantly hear about heavy elements decaying into other, more stable, ones but doesn't that mean that protons are escaping the nucleus? Doesn't that require HUGE amounts of energy to do? | [
"Radio active decay is mostly the actual nucleons changing type to a more stable nucleon for the system they are in. The two types to be aware of are:",
"Beta decay - A neutron decays into a proton, releasing an electron and an anti neutrino (this is beta",
" decay. beta",
" is p -> n + anti electron + neutri... | [
"Okay, so there's 3 main types of \"decay\" and fission. I think you're talking about the latter, but I'll hit all three:",
"The three types of decay are:\nAlpha, Beta and Gamma.",
"In alpha decay, a helium nucleus is emitted from a nucleus that is ",
". This leads to an ",
" in stability, and therefore a l... | [
"\"Very large nuclei (e.g. uranium) are so large that the coulombic repulsion of protons overcomes the strong force binding adjacent neutrons to protons. (this is because the strong force has an extremely low range). This causes the nucleus to split into two smaller nuclei.\"",
"I dont think the repulsion ever ov... |
[
"Is there a most efficient pendulum design/ratio? If so, why is it this ratio?"
] | [
false
] | By efficiency I mean the longest in time/distance traveled by the pendulum in one "drop" By ratio I mean arm length, amount of weight, the weight size, and the weight's shape. I tried googling for experiments but I couldn't find any. But there has to be a golden ratio for pendulums. | [
"By efficiency I mean the longest in time/distance traveled by the pendulum in one \"drop\"",
"To a first approximation, the time traveled by a pendulum is T=2 pi sqrt(L/g). So the longest time traveled by one period of a pendulum will always be an infinitely long pendulum.",
"By ratio I mean arm length, amount... | [
"So the longer the arm the longer the swing. And a pointed weight like a plumb bob, not a dispersed one like a crescent. The weight doesn't matter because everything falls at the same rate. I think that sums up what you said. But would a heavier weight not go as high each recurring swing?"
] | [
"If the only forces that apply are gravity and the perfect string's tension, then no, the mass of the weight does not matter.",
"However, if you model aerodynamic drag, then for a given shape a heavier pendulum will swing during a longer time."
] |
[
"Were there prehistoric trees larger than modern redwoods?"
] | [
false
] | null | [
"Yes, but probably not by much. ",
"At the moment the tallest tree is a California Redwood that is 116 meters tall. There’s a chance this is close to the theoretical maximum height as a tree grows taller, it becomes increasingly difficult for the tree to deliver water to its highest branches considering it is fig... | [
"Currently, the oldest petrified tree from 800000 years stood approximately 330 feet tall. The General Sherman Redwood is taller than that at 475 feet, but we don't know if that petrified tree was the tallest or if it just happens to be the tallest one we've found."
] | [
"growing to that height would have to be an evolutionary trait developed to counter the height of other trees. no tree would do that if it didn't have to. my hunch is that they won a battle of the tallest a long time ago and flourished where they are now. there will probably never be another tree like them ever aga... |
[
"Could an object big enough, fast enough, dense enough, \"break open\" a black hole?"
] | [
false
] | [deleted] | [
"Sometimes the answer is just plain no. This is one of those times."
] | [
"Better to believe the truth, than pretend I know the answer. Thanks for the knowledge :V"
] | [
"If an object crosses the event horizon of a black hole, it will not get out. It will in fact add to the mass of the black hole, making it larger. There is no breaking open or shattering of a black hole."
] |
[
"If an isolated land mass with all ethnic groups present was allowed to intermingle and mate for thousands of years, would it eventually result in one prominent skin color?"
] | [
false
] | The way I was thinking, you have your most extreme for all skin types. You have the whitest whites, blackest blacks, brownest brown and so on. Would it slowly become less and less extreme until you hit a median color. To further explain, the whitest person will only mate with someone darker than them. I realize tha... | [
"It would most likely depend on the environment. If it there was not much shade on the island, then those with darker skin would be much more likely to survive and pass on their genes. If there was a different environment, there would be different results. You can find more information on why some skins are darker ... | [
"In high UV conditions, a higher amount of melanin (which makes the skin dark) has a protective effect - it absorbs UV rather than the DNA. [edit:] Specifically, the higher number of melanin molecules means that less photons get absorbed by DNA - it's all a probability game. [end edit] In proteins like melanin or... | [
"It's actually the opposite direction. While dark skin does protect from UV related DNA damage that effect is not enough to stop an individual breeding. Skin cancers take years-decades to develop.",
"Where as the reduced production of Vitamin D at higher latitudes can cause increased rates of infant mortality and... |
[
"What happens to the spin of an electron when it leaves a nucleus?"
] | [
false
] | Lets say a photon collides with an atom, causing an electron on the outer shell to be knocked from orbit. From a classical sense, I would assume it takes some amount energy to change the spin of a particle, and that this amount of energy would depend on how far it's rotated. But, if an electron flies off of a nucleus,... | [
"The spin of an electron is always 1/2, you can never change that. However you can change its projection along some axis. If the Hamiltonian is dependent on some component of the spin vector, then the energy depends on the orientation of the spin of the particle. An example would be an electron in a magnetic field,... | [
"Whatever energy the electron gains during the process comes from the photon. If there’s a spin-flip in addition to knocking the electron out of its bound state, and the degeneracy of the magnetic substates is broken by a magnetic field, then there will be an energy absorbed or released by the spin flip."
] | [
"An electron's spin ",
"is ",
" either parallel or antiparallel",
" (opposite direction) with respect to ",
" directions. This is independent of any magnetic fields, that may or may not be present. The spin is never at a 90° angle (or 30° or 60°) to anything, but it ",
" be in a superposition of parallel ... |
[
"What are some ways animals have adapted to humans and civilization?"
] | [
false
] | null | [
"Not sure if you had anything particular in mind OP, but:",
"The most obvious example is domestication. Certain species of animals (and plants for that matter) have been radically changed by our hand. ",
"Some animals have learned to exist in cities and exploit our waste as a new food source. Pigeons are really... | [
"Yes, Planet Earth II ep. 6/6 covers animal live in cities. It's amazingly interesting"
] | [
"That's 20-25 thousand years too long. Cats were \"domesticated\" about 9-10 thousand years ago. One of the prevailing theories is that once humans started collecting and storing large amounts of grains this attracted the type of pests that cats hunt. Humans found it useful to have the cats around and the cats t... |
[
"Why does the hand get wet when we touch water?"
] | [
false
] | I mean, what is 'wet' when you think about it ? | [
"basically the bit about water that makes it feel wet is water's ability to adhere to substances due to its surface tension."
] | [
"Wet is just the combination of pressure and temperature. If you put on a tight latex glove, your hand would still feel \"wet\" (albeit a little differently because you're also feeling the pressure of the glove, but still)."
] | [
"There are two questions in this.",
"Water ",
" wet due to the adhesive (electromagnetic) forces between it and your hand. This is just a simplified version of the scientific definition of wetness.",
"However, water \"feels\" wet because our nerves and brain interpret these forces on our skin in a specific wa... |
[
"Is it just a huge coincidence that all the continents aren't completely submerged?"
] | [
false
] | It seems that the likelihood of there being enough water accreted on Earth to cover all the land isn't that far-fetched | [
"Its still an open question I think why we have \"just enough\" water for continents: we may have up to 10x Earth oceans of water in the mantle, with water circulating from mantle to ocean and back.",
"Kasting and Holm (1992) point out that the max. ocean depth seems to be set at the point of maximum thermal effi... | [
"I mean it could be possible. But we can't be sure until we actually get there (which is going to be far future stuff cause we haven't even gotten a decent way into the earth's crust at this point). ",
"There are microorganisms (i believe they are called lithophiles or endoliths) that live IN ocean sediment/rocks... | [
"we may have up to 10x Earth oceans of water in the mantle",
"Wait, you mean there's 10x more water ",
" the oceans? And it flows in and out through vents in the ocean floor?"
] |
[
"I read the Tardigrade can repair their DNA, which leads to a much larger resistance to radiation than humans have. Is this process well known and how can humans use this to our advantage?"
] | [
false
] | [deleted] | [
"Tardigrades are interesting creatures, known as water bears they have been observed to become dessicated and then 'spring to life' when re introduced to water even decades later. This is most likely relevant and we'll get to why in a minute.",
"DNA repair is an absolutely vital function to all living organisms. ... | [
"do the tardigrades have a mechanism to cleave thymine thymine linkages like plants. "
] | [
"\"is this process well known?\" ==>\"is this process well understood?\"",
"No. it is understood on a functional level but there are some minor nuances that elude us, so using it on much more then a theortical level is limited. Human splicing and adpotion is totally out of the question for right now because DNA t... |
[
"[Materials Science/Metallurgy] AskScience: I was told about an odd thing called \"Lead Disease\" today. I tried Googling it, but got no results. Repost as I received no visible responses yesterday."
] | [
false
] | I was doing some historical wargaming today with an old buddy who makes a lot of his own figurines. We were talking about the materials used and how he had managed to acquire the better part of a ton of scrap lead from various sources. He then told me a story about the person he learned the skill from. This person had ... | [
"This sounds a bit like zinc pest, where lead-zinc alloys slowly blister and fall apart. It's usually discussed about lead impurities in zinc but I've never seen any evidence that lead with sufficient zinc impurities wouldn't experience it too. There is also a more commonly known phenomenon called tin pest in which... | [
"(Pls see my edit above to address the possibility of pure lead corroding in a self-sustaining process in the presence of, for example, acetic acid and carbon dioxide.)"
] | [
"Okay, thank you. Combined with the other responses I have gotten it may be that the lead in use had a sufficient level of zinc in it to be affected. "
] |
[
"How does a higher redshift of increasingly distant objects imply an expanding universe?"
] | [
false
] | This has been bothering me for a while now but maybe someone here can offer a good explaination. If looking to distant objects is like looking into the past and those distant objects seem to be moving away from us faster than closer objects, then wouldn't that imply that objects are decceleration with respect to us? To... | [
"The flaw in your reasoning — to borrow your own words there — is that distant galaxies aren't actually in motion at all.",
"There are a few fundamental truths about the universe. One is called the Copernican principle, after Copernicus for obvious reasons. It says that there is no privileged place in the univers... | [
"Think of it like you and all your friends are sitting on the surface of a balloon which is being blown up. At first you are all close together, the space occupied by the balloon is small. As the balloon expands the people on the other side of the balloon move away from you faster than the people right next to you,... | [
"Well you can say everything is moving away from ",
", or you can say the universe is expanding. If you everything in the universe is moving away from ",
", then that puts us squarely at the centre of the universe. Humanity's history is filled with us being less special than we thought - we used to think we wer... |
[
"Why is there a window in the absorption spectrum of Earth's atmosphere at a wavelength of 4 μm?"
] | [
false
] | Looking at , it seems to me that there's a sizable window - i.e. a - in the graph for absorption, as per . , , , and appear to be entirely transparent to radiation of 4 μm wavelength, only appears to start absorbing it that point, and even has a window there. Moreover, is also minimal there. On top of , and show minima... | [
"The answer to this lies in what exactly causes the absorption bands to form in the first place. ",
"When a photon interacts with a molecule or atom, it can be absorbed via one of two mechanisms. If it is exactly the right energy (within a very fine tolerance), it can be absorbed to \"excite\" the atom/molec... | [
"It's for a piece of speculative fiction writing I'm doing, part of which regards the infrared radiation of a ",
"brown dwarf",
" (which is essentially a clone of the B component of ",
"WISE 2150–7520 AB",
") making it to the surface of an Earth-like planet orbiting it (said brown dwarf itself orbits a Sun-... | [
"I'm curious why you focus on the 4 μm window when there are similar windows centered around 1.05, 1.4, 1.7, 2.1 μm, etc. There's nothing particularly unique about 4 μm."
] |
[
"Do stars heat the space around them?"
] | [
false
] | So, we all know space is cold, and stars are hot; and we feel the suns heat through its light/radiation, so my question is, would you feel the suns heat as you approached it in space? For instance, if you threw a block of ice at it, would it melt on the way to the sun, or on impact with it? | [
"So there are three methods of heat transfer. Radiative, Conduction and Convection. The last two need a medium to transfer heat - like air or water. That like how you warm up when you lie under a blanket, or in a spa. Holding the hot thing next to you makes you hot.\nFor Radiative heat, all you need is line of ... | [
"Hi Bohemian_Songbird thank you for submitting to ",
"/r/Askscience",
".",
" Please add flair to your post. ",
"Your post will be removed permanently if flair is not added within one hour. You can flair this post by replying to this message with your flair choice. It must be an exact match to one of t... | [
"Yes, stars do indeed heat the space around them, and by a lot if it is close! You already mentioned feeling heat through radiation, and that is exactly what would allow you to feel the Sun's heat as you approach it. There are actually three types of heat transfer: ",
"Conduction",
", ",
"Convection",
", an... |
[
"If Alpha radiation is a helium nucleus (2 protons, 2 neutrons) and Beta radiation is just electrons, shouldn't combining the two just create Helium gas?"
] | [
false
] | If I come across a strong beta emitter, why couldn't I just use alpha radiation to neutralize it and just create normal Helium gas? It seems like these two radiation sources should de-ionize each other? | [
"There are plenty of electrons around in matter, there’s no need to introduce a β",
" source for that. When the α and β particles are emitted, they’re generally moving very fast; too fast to form atomic bonds until they’ve been slowed down a lot."
] | [
"To add to this it is fairly easy to detect helium gas around an alpha emitter and most of our helium sources on earth come from alpha decay. Rocks deep underground contain heavy radioactive isotopes which emitting alpha particles which quickly become neutral helium and build up in gaps within the rock."
] | [
"The amount of helium you get (within a human lifetime) is tiny even for the strongest alpha sources, if you are wondering about practical applications. To get relevant amounts you would have to wait for millions of years. Or extract helium from the ground where this process happened for millions of years.",
"And... |
[
"What are electromagnetic waves or what is an magnetic field?"
] | [
false
] | null | [
"When solving ",
"Maxwell's Equations",
" you find that an electromagnetic wave consists of an changing electric field and an changing magnetic field. ",
"These to fields are perpendicular to each other AND are perpendicular to the motion of the wave",
".",
"A field, be it electric or magnetic, is just a ... | [
"Its a really abstract concept. Think of gravity. It is also an abstract field. The electric and magnetic fields are just that, their own abstract concept used to describe phenomena we see mathematically. EM waves are a disturbance of that field that propagates, and happens to be a nice solution to Maxwell's equati... | [
"Think about gravity. The gravitational field is created by the accumulation of a bunch of particles with a particular property called mass. It acts through a vacuum, and indeed across all of space. The more particles you have, the stronger the field.",
"Now replace gravity and mass with electromagnetic and ch... |
[
"Does exercising your eyes help improve vision?"
] | [
false
] | null | [
"There is not enough conclusive evidence (i.e. well-controlled double-blind studies) for anything except accommodation/vergence training (",
"Barrett 2009",
"). But perhaps someone more familiar with more recent work can update."
] | [
"The Convergence Insufficiency Treatment Trial is a well known study which concluded that weekly office-based vision therapy combined with exercises at home significantly reduced symptoms of convergence insufficiency (a problem with your eyes’ ability to turn inward during near tasks such as reading). Accommodative... | [
"Children with an eye problem are at risk of amblyopia, a condition where one eye is weaker than the other ('lazy eye'). Basically the brain is confused by this image because it's either more blurry than the one from the other eye, or it doesn't line up with the other one. To overcome this, the brain essentially de... |
[
"How are molecular structures determined with such precision? How were they determined in the past?"
] | [
false
] | My question was inspired by learning that and are nearly identical molecules (C40H56O2), with the only difference between the two being that a single double bond is found in neighboring positions along a hexagon at one end of the molecule. These molecules are rather large. How are molecular structures determined so exa... | [
"Chemical characterisation is a fascinating and complex field in continuous evolution. So a complete answer to your question would require much more than a simple post. That said, the main analytical technique to resolve chemical structure with precision is nuclear magnetic resonance spectrometry, NMR. The principl... | [
"That said, the main analytical technique to resolve chemical structure with precision is nuclear magnetic resonance spectrometry, NMR. ",
"Shots fired towards the X-ray folks ;)",
"Kidding, I'm a protein NMR guy myself. But really, as long as it crystallizes and you got beam line access for high resolution, x-... | [
"For large protein structures, in the past the technique used was to crystallize the protein, then take xrays of the crystals, using x-ray diffraction to determine the structure. This was the technique used to determine the helical structure of DNA back in the 50s. The issue in the biological sciences is that many ... |
[
"What happens if the fuel rods in a nuclear reactor are lowered too far/quickly?"
] | [
false
] | null | [
"Commercial reactor designs don't move the fuel rods. The fuel rods are stationary and control rods are inserted or withdraw. The control rods utilize boron or some other neutron poison to control the reaction rate. Inserting the control rods lowers reactor power and withdrawing the rods causes power to increase. ... | [
"*In properly designed modern reactors which are water-moderated and have a negative void coefficient.",
"In a graphite-moderated, water-cooled design with graphite tipped rods and a positive void coefficient, however, if all but four of the control rods are completely retracted and then the reactor tries to SCRA... | [
"Intentionally Operating the reactor outside of its analyzed profile on top of violating a reactor safety limit for minimum control rod insertion can cause significant damage. That's entirely based on human error and defeating the safety systems which would have tripped the reactor well before the conditions of the... |
[
"What is the importance of irrational numbers?"
] | [
false
] | While I know that irrational numbers such as pi or e are important, is there anything particularly important about them being irrational? | [
"even the square roots of certain numbers (like 2) are irrational. pi and e are in a sense even more.. let's say you need to put in more work to describe them. \nthe roots are zeros of polynomials with rational coefficients. pi and e aren't. ",
"when you start out with rational numbers (ie fractions of integers ... | [
"Being irrational is usually 'worse', at least from a computation perspective than being rational.",
"So the knowledge that we gained when we discovered that pi and e are irrational (and in fact transcendental) was a negative result -- e.g. we can stop searching for a rational number representation of pi because ... | [
"As has been pointed out, in reality \"most\" numbers are irrational. There are more irrational numbers than rational ones. Now you brought up e and pi. I don't know if their irrationality in and of itself is in anyway special. But rather one can say that there is SOME number that relates the ratio of the diame... |
[
"[Physics] What are the differences between AC Electric Power and DC Electric Power?"
] | [
false
] | [deleted] | [
"Quantum mechanics is too much detail (out of scope) for this question.",
"Since you already know that AC and DC differ simply by their frequency, let's talk about what's really going on:",
"1) We use AC because it's easy and safe to generate with spinning magnets.",
"2) DC is simply a subset of the larger re... | [
"AC can be seen as \"pushing, pulling electrons, repeat\" at ~50-60Hz, while DC is just pull electrons from - to +."
] | [
"The easiest metaphor to understand this concept may be perhaps water: If you push water all the time, you'll require a lot of water and constant pressure. If you push/pull alternately, you need less water and less pressure to generate a movement of the water at the end of the line. Of course, this metaphor is terr... |
[
"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! ... | [
"Why is it that we take/suggest better decisions to problems of others while when the same problem occurs to us, we tend to get confused and unable to take a proper solution?"
] | [
"Is there a term neurologically that defines the exact moment when someone who is brainwashed breaks through the psychological indoctrination and realizes the facts are against that brainwashing"
] | [
"Perhaps it’s a trait that was deemed successful to help us survive to get us to work together with other people and be more Social."
] |
[
"If I pick up my coffee right after I stir it, so that it's still swirling around, will there be a gyroscopic effect making me less likely to spill it?"
] | [
false
] | null | [
"In theory yes, but in reality you'd probably be more likely to spill it. Once you tilted the cup at all you would lose the swirl as the liquid deformed against the cup wall and that creates imbalances. You can actually try this. Stir up a liquid in a cup where the liquid mass is as great as possible relative to th... | [
"Wouldn't the vortex also push the edges of the liquid mass further up the walls of the mug than if it was still, thus reducing the overall angle of tilt required before spilling?"
] | [
"I was thinking the same thing. The liquid would go up the edges much higher than if it wasn't spinning."
] |
[
"How does DNA function as an information storage medium?"
] | [
false
] | I wanted to relate this topic to microarrays, but I searched and didn't find much about it. | [
"There are a few layers to it, but basically the DNA sequence is read by proteins that transcribe the sequence into an intermediate message (mRNA). Those mRNAs are then translated by ribosomes into proteins, which then allow a cell to perform specific functions. Not all RNAs are translated, some perform functions i... | [
"Someone already responded with explanation of the central dogma, but I think the confusion arises from over stating the central dogma",
"Microarrays in biology are basically a technique where scientists check for certain genes being active. The reason it is confined to active genes is because modern techniques m... | [
"Do you mean in an electronic sense or biological sense? Cause those two operate differently. Electronically you can treat the ATCG base pairs as the 1 and 0 bits of information that something like a computer can read. Biologically DNA is read by ribosome and great proteins by having RNA attach peptides in sequence... |
[
"Why do I get nauseous when my blood sugar is low, or when I haven't eaten for a long period of time?"
] | [
false
] | I haven't monitored my glucose levels in a while to be able to verify that it's low EVERY time that I don't eat for hours, but I know that in the past, it's been low when this situation has occured. Why do I feel nauseous and lose my appetite when my sugar is low, rather than more hungry? Thanks! | [
"When your blood sugar is low, ",
"glucagon",
" is released into your blood stream by your pancreas. (glucagon is a hormone that tries to increase the amount of sugar in your bloodstream) This glucagon can induce hunger but can also ",
"cause a feeling of nausea",
"."
] | [
"Ok, so what is it about glucagon that would make one nauseous? Or give them a headache? These seem counter productive if blood sugar is low."
] | [
"I was trying to find the answer to this while responding initially, but I couldn't get a firm answer. I have not taken endocrinology yet so I can only speculate. ",
"I was trying to come up with a mechanism based on acid-base balance where glucagon increased fatty acid metabolism resulting in an increase in ... |
[
"Schizophrenia and optical illusions…"
] | [
false
] | Schizophrenics have the ability to decipher optical illusions. What is it about the brain of person who has been labeled as schizophrenic that doesn't allow them to be fooled by these illusions, as most of us are? Can anyone enlighten me on the cognitive processing that is occurring here? Check out the video included i... | [
"I assume OP is referencing this, ",
"http://www.wired.com/wiredscience/2009/04/schizoillusion/",
"It's the most recent article I can think of that made the rounds on the internet.",
"... I have a weird memory."
] | [
"Well, the Wired article that ablackhat linked has a decent description of the \"what\" that happens:",
"When healthy subjects looked at the concave faces, connections strengthened between the frontoparietal network, which is involved in top-down processing, and the visual areas of the brain that receive informat... | [
"Sorry...just put the site up. "
] |
[
"If lightning strikes a car, does it fry the radio? What about a charging phone?"
] | [
false
] | Say lightning strikes a car. The car has a stock radio and a charging phone in it. Does this fry the radio or phone? How about an automotive inverter(built in or plug in)? Would any specific electronic system in the car be fried? | [
"It can, but it might not. Anything that is connected to the outer metal shell of the car, in any way, can suffer from the effects of the strike. The radio and the charging phone are a part of the system that is grounded to the frame of the car. They might get fried.",
"However, the lightning wants to find the... | [
"Lightning, by its nature, is unpredictable. It's possible to be struck no matter where you are. But being inside a car is a relatively safe place.",
"The lightning is trying to get to ground. Stay out of its way. Lightning does not really \"see\" in straight lines. Just being directly under a CB whip is not... | [
"It's actually really interesting. I know the bit about fairday cages and how the tires are irrelevant. I've been told the car is the safest place to be in a storm; assuming your not touching metal.",
"Could it blow up something like the rear window defogger? Certain cars use them as antenna and they usually are ... |
[
"Can [human] vision defects be corrected for at the display end by transforming the displayed image?"
] | [
false
] | My understanding is that vision defects such as myopia/hyperopia are a result of (usually) a misshapen cornea which focuses incoming light too far forward/back from the retina, leading to blurry images. Glasses/contact lenses correct this by applying a converging or diverging transform to the incoming rays, essentially... | [
"I can't think of a circumstance in which this is possible. The most practical problems lie in the issue of focal length. Eye glasses an contacts only work because they a fixed position relative to the eye. ",
"Another issue is that computer screens don't emit focused light. It would be possible to put a lens in ... | [
"Take a look at Stephen Mann's ",
"pinhole armac",
" which is sort of the projector analog of a pinhole camera where everything being photographed is in focus. It allows an image to be seen clearly regardless of where the eye is focused.",
"I also know a person who sees objects rotated differently in one eye ... | [
"One of the things I've heard about with the ",
"Oculus Rift",
" (a new virtual reality headset that's popular in gaming) is that despite the screen being a few inches away from your face, people still experience eye disorders as if what they were viewing the object as a sceen many feet away. This seems to be e... |
[
"How does Proteinase K avoid eating itself?"
] | [
false
] | A protein that digests proteins, but does not get digested by itself. | [
"My best guess would be that the protein itself doesn’t have the desired sequence for catalysis. For example, I used to work with proteinases that have a cleavage preference for Arg-Arg and did exhibit autocatalysis because they had Arg-Arg sites within the protein. ",
"Proteinase K also has an amino acid sequenc... | [
"You worked with Trypsin I’m guessing? Trypsin does auto lyse to an extent. Proteinase K most likely auto lyses as well but if there are other targets than it’ll be clipping them if they’re more present. Proteinase K clips keratin strands like hair. The cleavage sites it targets are going to be present on most ... | [
"I love it. I never grew out of my “I’m 4 and snakes are my favorite animal” stage and now they’re my career."
] |
[
"Why must there be a \"charge balance\" in every chemical solution? What would happen if we tried to create an aqueous solution with just K+ ions in it?"
] | [
false
] | null | [
"I don't think you understand the scale of the forces involved. If even a fraction of a mole of K+ ions existed in a beaker without being balanced by negative charges the force pushing the ions apart would be higher than the forces inside a bomb."
] | [
"Electrostatic forces are really, really strong. If you somehow put in enough of one type of ion, the solution could just explode apart.",
"That said, small charge imbalances can and do exist. Your biological cells use ion channel pumps to control the flow of particular ions in and out through the cell membrane. ... | [
"Because a collection of like-charges brought together carries an obscene amount of energy. So much so, that the Earth itself only carries about 5x10",
" C of charge. That's about 3.1x10",
" electron charges. The mass of a single K+-ion is about 6.5x10",
" kg, so if this charge imbalance was caused only by K+... |
[
"If black holes have a singularity at the middle, how can there be different \"size\" black holes?"
] | [
false
] | I know I am vastly simplifying itand that my understanding of physics is rudimentary at best, but I was explaining black holes to my daughter and wife last night and was asked the question in the titleand was stumped. Is my understanding of a singularity correct in that it is a collapsed star down to a volume of zero, ... | [
"The curvature of spacetime induced by the central singularity is proportional to the mass of the object.",
"Usually the size of a black hole refers to the radius of its event horizon, which for a non-spinning spherically symmetric object is given by the Schwarzschild radius (Rs):",
"Rs = 2MG/c",
"where M is ... | [
"Put differently:",
"The event horizon of a black hole is proportional to the its total mass, including the mass that has gone into it, and ignoring Hawking radiation since it is a negligible effect for stellar to supermassive black holes. ",
"The singularity is inferred to exist because there is no known force... | [
"Just to clarify something: we don't really know that there really is a singularity (something infinitely dense with zero volume) at the center of a black hole. This is just what one of our models (general relativity) tells us, but we sort of know for various that this model/theory isn't valid at all length scales.... |
[
"What causes a dust devil? Is it different than a tornado?"
] | [
false
] | I've seen waterspouts, tornados and dust devils they seem similar but the latter two seem a lot less powerfuk | [
"Dust devils form on fair weather or sunny days when there is lots of wind shear in the air",
"Not sure where you're getting that last part, it's definitely not true. From the ",
"American Meteorological Society glossary",
":",
" Dust devils are best developed on a hot, calm afternoon\n",
"In general, you... | [
"Dust devils form on fair weather or sunny days when there is lots of wind shear in the air",
"Not sure where you're getting that last part, it's definitely not true. From the ",
"American Meteorological Society glossary",
":",
" Dust devils are best developed on a hot, calm afternoon\n",
"In general, you... | [
"Thank you - so, does that mean that the difference in power is the force of the thunderstorm?"
] |
[
"What is it that makes bulletproof glass so strong?"
] | [
false
] | null | [
"Bulletproof glass is made up of polycarbonate layered between glass. The polycarbonate distributes the force evenly across the glass which helps break up the force at the same time. These layers form a laminate. ",
"When a bullet strikes bulletproof glass, its energy spreads out sideways through the layers. Be... | [
".762mm round",
"mind the placement of the decimal point though.",
".30 round as you state above is correct, as that's .30 caliber (basically .30 inch). With mm though, I think you meant 7.62mm.",
"Incidentally, 7.62mm and .30 caliber are about same thing in terms of diameter. However, the amount of powder be... | [
"polycarbonate layered between glass",
"Is that like PVB? I understand that the modern era of automotive glass began when engineers took two panes of laminated glass and separated them with a thin layer of PVB."
] |
[
"Why does the human brain so easily extract faces out of otherwise random visual data?"
] | [
false
] | Is there some evolutionary advantage to this? | [
"There is a patch of cortex called the fusiform gyrus with an area specialized for identifying faces. It seems to constantly be doing a type of template matching, matching subsets of visual input to face-shaped patterns. It is my opinion that, because a larger chunk of cortex is devoted to IDing faces than any othe... | [
"The fusiform gyrus (located in the inferior right temporal lobe) is the correct answer. You can see this gyrus light-up even when something RESEMBLES a face. ",
"Example 1",
". ",
"Example 2",
". Interestingly, autistic individuals have a much harder time with this, and will likely only see a bundle of veg... | [
"Certainly there are advantages to it, but also disadvantages.",
"If someone (human) is stalking you in the forest, and you're able to pick out their face from the surrounding foliage, then you've got an extra split second to fight/flight reaction. Likewise, if you can pick out the tiger/bear/etc's face just tha... |
[
"Why do our teeth require such high maintenance, unlike any other animal, and unlike any other of our organs?"
] | [
false
] | All I can guess is our inappropriate modern diet, but is that all there is to it? | [
"Part of it is due to more sugar than we would get in the wild however I'll split my answer into two parts, addressing different issues.",
"\nFirstly we need to look after our teeth more than animals because we generally live a lot longer than other animals do, and longer than we have evolved to live (that is our... | [
"The recent extension of lifespan in humans is primarily due to better nutrition, less predation and improved health care. Many domesticated or captive wild animals live much longer than their wild cousins due to an easier life (and can have similar problems to humans, including dental issues)."
] | [
"It's largely due to our inappropriate modern diet. See ",
"Nutrition and Physical Degeneration",
" for the comprehensive work on this subject. Humans consuming traditional diets are nearly free of dental carries and remain so even until a very old age, most live out their lives without a single dental carry."
... |
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