title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
|---|---|---|---|---|---|
[
"What is the difference between steam, fog and 100% humidity?"
] | [
false
] | null | [
"It is all water, water vapor, and air. ",
" \nWater vapor is what the gaseous form of water is called. ",
" \nSteam is created when enough energy (heat) is applied to cause the liquid water to change phases from liquid to gas. Steam is actually clear. The white puffy stuff you see coming off a pot of boiling w... | [
"This is just my understanding: steam is hot water that has reaches the gas phase. 100% humidity is when the air contains the maximum amount of water that can be dissolved in it. Just like a glass of water can only have so much salt dissolved in it, the same goes for air and water vapors. Fog, is just a fallen clou... | [
"Correct on fog. Fog and clouds are both water vapor that has condensed into tiny tiny droplets that are either the same density as the air around them or are light enough to be lifted by wind or updrafts. "
] |
[
"Is nitrogen dioxide a second messenger?"
] | [
false
] | I'm pretty sure my biology teacher is mixing up NO2 and NO. NO2 is a toxic brown gas. NO is a common second messenger, noted for its role in the transduction pathway of nitroglycerin. The teacher asserts that NO2 is a second messenger, but I can't find a thing about it on the internet- all of the information is for NO.... | [
"I answered your modmail, but I'll repost the answer here:",
"He might be talking about the nitrite ion, which is NO2-. This is a stable breakdown product of nitric oxide (NO), that can convert into NO in tissue areas that are relatively hypoxic.",
"If he said nitrogen dioxide, he is incorrect and likely just t... | [
"Thanks for both replies. You are a minor god of biology."
] | [
"Nitrate, nitrite, and nitric oxide are biochemical messengers. Nitrogen dioxide I haven't heard of being used by cells. All these molecules are toxic at high concentrations. Even hydrogen sulfide is used as a biochemical messenger. "
] |
[
"Will going for a sunbed give my body vitamin D?"
] | [
false
] | And if so, will it give me the same amount as I would from lying in the sun in a warm country for the same period of time? | [
"Yes",
"UVB (UV rays between 295 and 297nm) is the radiation needed for your body to synthesize vitamin D in the skin and is also emitted by tanning beds. Whether or not this is equivalent to lying in the sun for the same amount of time is hard to say though if ALL other factors are controlled for e.g. skin expos... | [
"Thanks. I'm sure I read something a while ago saying that the amount of vitamin D you can get from consumption is insignificant to how much your body can get from sunlight. I take it that isn't true then?"
] | [
"Not insignificant but you would have to eat A LOT (more than you would normally eat but less than so much it would make you sick) of the foods that have a dietary level of Vitamin D for it to equal the amount you synthesize just from standing in the sun for a few minutes (again how much sunlight is enough is highl... |
[
"Why do wisdom teeth come in so late, and for so many people need to be removed?"
] | [
false
] | What biological advantage does it serve that wisdom teeth come in so much later than the rest of the adult teeth? What signals the teeth to be ready to come in? What causes the need for wisdom teeth to be removed? Thanks in advance | [
"Teeth come out in an organized fashion with molars coming out one after another as a general rule. Wisdom teeth just so happen to be the last one. Anthropologically, it has been suggested that Wisdom teeth are vestigial, or not really necessary anymore. It was almost certainly an advantage to have many molars when... | [
"Wisdom teeth can replace lost teeth. I have two adult teeth that never existed/ didn't come in, and 1 wisdom tooth. Wish braces I closed the gaps and have a normalish mouth.",
"In the wild, someone could loose a few teeth, and then have wisdom come in as replacements. They only overcrowd mouths because modern... | [
"Evolution only operates to make systems work well up and keep you competitive up to the age at which you breed; from then on, you are surplus to requirements, and evolution generally won't fix any problems you have (leaving aside parental/grandparental care etc).",
"So, if - in the ancestral wild - wisdom teeth ... |
[
"Can you recommend some books on abiogenesis and/or cosmology?"
] | [
false
] | Having recently read The Selfish Gene (Dawkins) and The Grand Design (Hawking), I am interested in learning more about cosmology and biology - particularly evolution and abiogenesis. Can recommend some good titles or authors? | [
"Origins of Life by Freeman Dyson",
"Life in Space: Astrobiology for Everyone by Lucas John Mix",
"Astrobiology: A Brief Introduction by Kevin Plaxco",
"Life Everywhere by David Darling",
"Rare Earth: Why Complex Life Is Uncommon in the Universe by Peter Ward",
"ALso there are some talks ",
"here",
".... | [
"I didn't read it, but this other book by Simon Singh was pretty good, so I trust that his new book about the Big Bang is similarly good. It's called \"Big Bang\".",
"Then I hear a lot about Bill Brysons \"Short story of almost everything\" or something like that. His other books are extremely funny and he is not... | [
"In particular, I've found two potential buys on Amazon for abiogenesis - has anyone read either of these?",
"Emergence of Life on Earth - Iris Fry",
"Life's Origin - J. William Schopf"
] |
[
"How does the sun revolve around the galactic core?"
] | [
false
] | [deleted] | [
"The same way Earth orbits the sun without being sucked into it—gravity causes an acceleration toward the center, but tangential velocity keeps it in an elliptical orbit. Black holes aren't magical space vacuums; to outside observers they're basically just massive spheres (modulo some weird effects near the event h... | [
"The arms aren't \"real\" structures; they're apparent structures that come from the arrangement of the stars and the way they move. It's not entirely clear what causes them. Until recently it was widely believed that the spirals were sort of \"pressure waves\" rotating around the center. The stars themselves orbit... | [
"The arms aren't \"real\" structures; they're apparent structures that come from the arrangement of the stars and the way they move. It's not entirely clear what causes them. Until recently it was widely believed that the spirals were sort of \"pressure waves\" rotating around the center. The stars themselves orbit... |
[
"How does the vaccine distribution work in the human body. I saw some people say something that it stays at the injection site and others say it doesn’t. Don’t all vaccines spread in the body ?"
] | [
false
] | I’d really appreciate some articles/studies showing how distribution works to better understand. | [
"The mRNA vaccines do travel away from the injection site, but not via the blood — it's mainly via ",
"lymphatic vessels",
" (Wikipedia link), which takes the mRNA to draining ",
"lymph nodes",
". ",
"With a slightly different and earlier mRNA vaccine -",
"Following longitudinal assessment of the vaccin... | [
"It was my understanding that the vaccine stimulates your muscles to produce proteins that are in the virus, leading your body to make antibodies for the virus. The antibodies give you the protection and they travel in your bloodstream. ",
"It is certain that the protection does not just stay in the injection ... | [
"A lot of it drains away into the Lymphatic system.\nAnd the mRNA can also be taken in by muscle cells which begin producing the spike protein for a while until the mRNA is degraded by natural cell processes.\nCells constantly break down and build up their components.\nWhichever cell take in the mRNA will produce ... |
[
"What would theoretically happen to a solid object if it were rotated at relativistic speeds?"
] | [
false
] | I was just wondering about what would happen if some solid body, like a sphere, were rotated at speeds comparable to the speed of light. I know about special relativity's implications for an object moving on a straight path at relativistic speeds, but what would this imply for a rotating body? It gets weird when you c... | [
"Probably tears itself apart from centrifugal force way before reaching anywhere close to "
] | [
"tear itself apart/shatter because, well, ratio of circumference to diameter wouldn't, from its own perspective, be equal to Pi anymore. If you want something rigid spinning relativistically, you have to create it already in motion.",
"Some ",
"info on wiki",
" about this."
] | [
"You would have to have something strong enough to even withstand the force of not tearing itself apart.",
"For example, CDs ",
"http://www.youtube.com/watch?v=JOb6Z5Tja68"
] |
[
"Teaching your child science. Where to start?"
] | [
false
] | We are organizing a homeschool group and the oldest three kids are 6 years old. I'm going to be teaching them history and a science. I have no idea where to start with science. Should we study nature? Leaves, trees, anything in the backyard? The Animal Kingdom, classifications and species? Space, planets, and stars? ... | [
"I remember learning science when I was that age, and I've also taught classes at a zoo to kids of all ages. I think when they are younger, kids can have a harder time grasping concepts that they don't see/experiences themselves. Basically, I would probably stick to macroscopic sciences until they are a little olde... | [
"Keep in mind that young children are natural scientist, they are curious about the world around them and want to know how it works. Find out what the kids are interested and engage them, please don't teach at them. The worst thing that could happen is to crush this curiosity with memorization. If it is nature ... | [
"Start with things they know. Weather, for example. ",
"The precipitation cycle is a good one.How it changes from a gas to a liquid, and how it can even become a solid (hail, snow). Water is a great stepping-stone.",
"It's the first thing I remember learning. "
] |
[
"The speed of gravity: faster than light by >10 orders of magnitude?"
] | [
false
] | I imagine this is probably a reasonably well-known "unorthodox" paper in physics circles: , which proposes that the speed of gravity must be much higher than that of light (if not quite infinite). For me his arguments make a lot of sense, and I can't disprove them. Particularly the one about the instability of orbits w... | [
"Why do people need to be warned of a pdf?"
] | [
"There is no experimental evidence to suggest that gravity travels faster than light. There are several experiments being set up to try to detect gravitational waves, and until they start getting results, its too soon to throw out general relativity."
] | [
"Adobe Reader is so stunningly bad that it frequently crashes people's web browsers."
] |
[
"If we share 98% of our genetic material with chimpanzees, what is the variance within the human population as a whole?"
] | [
false
] | null | [
"Not an answer to your question, but just to give some perspective: Humans also share something like 75% of our genetic code with ",
". Comparing percentages doesn't really say much."
] | [
"The common answer is that on average the genetic similarity of two people is between 99.5% and 99.9%. The answer partially depends on how we define genetic variation (",
"wikipedia",
"). If we just count the variants that have been observed, current databases have about 54 million short variants (changes to a ... | [
"I think, from what I remember, we share 25% of our DNA with dandelions.",
"An important factor to remember is that it's not just which genes are present - it's also which are turned on/off, depending on the context of other genes' presence/absence or on/off state. So we can share the same genes, but if mine are ... |
[
"What would happen to a puff of smoke in a vacuum chamber?"
] | [
false
] | [deleted] | [
"The gaseous part of the smoke, which is invisible, would expand to fill whatever enclosed space it was released in.",
"The part of the smoke that you can see is particulate matter, it is essentially very high molecular weight agglomerations of the products of incomplete combustion. These particles would simply f... | [
"That makes sense. Now say gravity was negligible...how would the particulate matter act in the presence of the expanding gas? Would the gravitational pull of the particles themselves act upon each other?"
] | [
"Now say gravity was negligible...how would the particulate matter act in the presence of the expanding gas?",
"Particles will bounce around until they stick either to each other or the chamber walls due to intermolecular forces. The sparse gas would exert drag and slow them down somewhat; the amount of drag woul... |
[
"In an 80-year life span, roughly how many generations of bacteria live and die in one's gut?"
] | [
false
] | null | [
"The article I linked to doesn't say that this is an exponential phase measurement; could you please explain why you say that it is? I took it to be an estimate of the normal steady-state generation time. When would there be exponential phase growth in the gut, other than after antibiotic treatment?"
] | [
"The article I linked to doesn't say that this is an exponential phase measurement; could you please explain why you say that it is? I took it to be an estimate of the normal steady-state generation time. When would there be exponential phase growth in the gut, other than after antibiotic treatment?"
] | [
"…in the intestinal tract, the coliform's generation time is estimated to be 12-24 hours…",
"So about 50 000, give or take, for ",
"."
] |
[
"Why is the hazard/mortality ratio for HbA1c higher for the lowest levels? Is it explained primarily by a significant fraction of the ill population having high RBC turnover?"
] | [
false
] | . Risk of death is higher for 4.3/4.4 relative to 4.8. I mean, Mike Lustgarten reports that mortality ratio is lower for fasting glucose of 84 than for 75 (b/c high RBC turnover is an indication of something bad?) And what IS the percent of the population that has high RBC turnover? Like, if you want to do a full analy... | [
"HbA1c is a quantification of the amount of the \"normal\" variant of haemoglobin [HbA]* which has been glycated at sometime during its working life. Glycation means having a glucose molecule permanently bonded to the HbA molecule - the glucose attaches at a characteristic spot on the HbA molecule at a consistent... | [
"You *only check HbA1c levels on people with diabetes. Very high blood sugars tend to kill diabetics slowly. Very low blood sugars will do it quickly. If someone is on glucose lowering meds and their HbA1c is low, they probably have some dangerous hypoglycemic episodes.",
"Edit: * not “only” but “only do the foll... | [
"I would like to point out some problems with using A1C as a metric for blood sugar stability.",
"Some people have longer living red blood cells and can measure on an A1C test at over 7.0 but not have any blood sugar issues.",
"We would tell a type 1 diabetic that an A1C of 5.5 is perfect and it correlates to a... |
[
"Is it possible to accelerate to a set speed instantaniously?"
] | [
false
] | Hello science people. I was wondering if it is possible (I know its not with current technology but maybe one day) to accelerate to per say 50 km/h without starting at one, two or thee so on and so forth. I was just kind of curious! :) - Cheers | [
"Instantaneous acceleration requires infinite power. So no."
] | [
"Jumping instantaneously from one speed to another speed would require infinite acceleration, and therefore an infinite force, which does not exist. Also, the object being accelerated would feel an infinite g-force (inertial force) and therefore be crushed to zero width."
] | [
"Thanks lad have a good one"
] |
[
"Why did animals never evolve the ability to synthesize food from sunlight?"
] | [
false
] | Somewhat related: did plants and animals evolve independently, or did one come from the other? | [
"Some animals do. Corals contain a ",
"photosynthetic algae",
" that directly provides energy to the coral. There's no particular \"why\" beyond that other than it just didn't happen for other animals. ",
"Both plants and animals evolved from bacteria, branching from bacteria separately. The first photosy... | [
"You've got it exactly backwards; a plant develops a large surface area because it can photosynthesize, not the other way around. Early proto-plants and proto-animals were similarly-sized colonial systems. ",
"Your answer attempts to say \"why\" the complex animals we have now haven't gone back and picked up add... | [
"Not for sloths",
" (both fur and camoflage here, and even the suggestion of extra nutrients). Body shape seems to work out fine for both sloths and algae; as I said, the reason it hasn't gone further is either \"it just hasn't yet\" or \"difficulty further integrating systems\" rather than anything to do with s... |
[
"How come when I hit my dab pen (THC Oil) my head and ears get an intense, burning-like feeling for like 30 seconds or so?"
] | [
false
] | null | [
"We can't comment on personal anecdotes / isolated incidents without resorting to speculation which we try to avoid."
] | [
"Gotcha, wasn't sure if there was anyone else who experiences this and knows exactly what it is. Is there a sub you suggest I post to? I'm genuinely curious why this happens to me."
] | [
"You can always try ",
"/r/findareddit",
" for help in finding a sub."
] |
[
"Do tornadoes change the contours of the land?"
] | [
false
] | When a significant tornado hits, for example, a hill, will there be visible changes do the shape or height of the hill? I'm not interested in wind erosion that takes place over hundreds of thousands or millions of years. Is there ever a significant impact from a single tornado on the contours of the land? | [
"Not that I've ever seen. Maybe if it passed over an area dominated by loose sand but usually earth stays pretty much in place. The wind of a tornado is great at getting underneath things that are above the surface but not great at moving things that are flat. Also, the site that a tornado touches down on doesn't l... | [
"In response to the second photo, I actually live in Tuscaloosa! Such an exciting place to observe weather. I have definitely seen a lot of tornado tracks, but what I meant was that the actual touch-down point isn't blasted like a meteor hit it (which would change the topography, like in the OP's question). It just... | [
"Also, the site that a tornado touches down on doesn't look \"hit.\"",
"Depends on what you call \"looks hit\" I guess.",
"https://www.nssl.noaa.gov/about/history/may3rd/images/aerial.jpg",
"https://axiomamuse.files.wordpress.com/2011/04/tuscaloosa-aftermath.jpg",
"http://www.weathercast.co.uk/typo3temp/pic... |
[
"Do scientists/those in software sciences really believe that one day, we’ll be able to type out text messages/words using our thoughts (via implant maybe)? Is this a realistic vision of the future?"
] | [
false
] | null | [
"There are already versions of this. See BrainGate or just google \"typing with thoughts\""
] | [
"Ah I see. In that case, I actually recommend making a new post in our sister-sub ",
"/r/asksciencediscussion",
" which is more geared to such hypothetical / speculative questions and is more about open-ended discussion. I would recommend the using the clearer version of the question you've got in this most rec... | [
"I wish this thread blew up because I’d love to read more replies! Where else could I post this to possibly get more traction? And yes that’s amazing. I have seen stuff like that.. I feel like we all forget that this technology exists, so you think we may have it on a consumer level at some point?"
] |
[
"Do animals dance?"
] | [
false
] | null | [
"What about birds that seem to dance to music like Cockatoos? ",
"http://www.youtube.com/watch?v=N7IZmRnAo6s"
] | [
"Fair point. Seems like some do!\nNot sure why the bird does this, would seem odd that this is innate behaviour seeing as music is not a natural phenomenon.",
"For example cobras ",
"\"dance\"",
" to the music of the pipe player but its not the music that's making them do that*; its the ",
"motion of the pi... | [
"Yes but obviously not to music, it's normally to attract mates:",
"Video here"
] |
[
"Does chewing food 50 times increase nutrition availability?"
] | [
false
] | Additionally, what are the full benefits of chewing a lot before you swallow? | [
"To disagree with the other commenters - chewing does affect nutrition. Not in the way you mean in your question, but in several important ways.",
"To be clear, chewing 10 times vs 50 is not nearly the same difference as blended vs chewed. In regards to 1. & 2. (above) the degree of chewing is unlikely to make an... | [
"It doesn't, and there are no benefits to it. It's crackpottery."
] | [
"Salivary glands start to function as soon as you take the first bite of food and conyinue to produce saliva as you chew. The mucus from the salivary glands lubricates and binds food as you chew it. Mucus holds the chewed food together in a slippery mass, coating it so it can pass down the esophagus into the stomac... |
[
"When global mean sea level rises by one inch, how are various local high tide levels affected?"
] | [
false
] | Is there a dominant pattern where the change is either greater or less than one inch in most places? | [
"Local sea level is changing differently than the global average - depending on where you are. (For example see this map ",
"here",
") This variation is due to local temperature/salinity changes, shifting currents and rising or sinking land (due to subsidence, earthquakes etc.).",
"Tides are essentially shift... | [
"If you have a source I can read that supports local high tides increasing by same amount as local mean level, that would be great."
] | [
"Hmmm, thinking about this a bit further local high tides could change by a different amount than the rise in mean sea level - they could increase faster or slower if there's a change in tidal range (difference between high tide and low tide) due to sea level rise.",
"Sea level rise may in some locations change t... |
[
"If the common flu (Influenza) is caused by a virus, why am I told to put a jacket on when its cold?"
] | [
false
] | [deleted] | [
"Cold temperature doesn't cause viral diseases, obviously. There is a very strong correlation between cold temperatures and several viral diseases -- influenza and respiratory syncytial virus particularly tend to be much more common in the winter (in temperate climates). The reason for this is still not entirely ... | [
"also to further prove my point I asked a sick relative to drink directly from a bottle and I breathed in his sneezes and cough air (disgusting but drives my point) and drank from that bottle to expose my throat and nose to the virus",
"...what did you expect to happen?",
"and as expected I got sick shortly aft... | [
"To convince people who don't take facts well. I don't live in a first world country where everyone knows about things like these , here people are adamant and have 0 knowledge about the facts, they would rather wear 10 jackets than just covering thier mouth and getting repeatedly sick"
] |
[
"How do we know the distance of celestial bodies from earth?"
] | [
false
] | null | [
"For nearby objects like planets within the solar system: radar. They beam out a radar pulse toward, say, Jupiter and measure how long the light takes to reflect back.",
"For somewhat farther objects like nearby stars, ",
"parallax",
". Hold out a finger in front of your face and close one eye and mark where ... | [
"Using a variety of techniques to build the so-called \"Cosmic Distance Ladder\". Terence Tau has a really nice set of slides explaining it clearly: ",
"https://terrytao.wordpress.com/2010/10/10/the-cosmic-distance-ladder-ver-4-1/"
] | [
"Do these measurements get affected by things like refraction off of our atmosphere or other gases present in between these distances?"
] |
[
"Are there issues preventing lux operon expression in eukaryotes?"
] | [
false
] | What's the major challenges of getting bioluminescent plants / animals? Are the products toxic to the transgenic organisms? Maybe difficult to cause expression, even with the correct promoters or a visible cell choice (ex: in keratinocytes)? I believe something similar in plant chloroplasts has been done, but I haven't... | [
"There a two aspects of your question that I would like to answer:\n First, I can confirm, that one can have bioluminescence in transgenic eukaryotes. The luciferase gene (a gene from a firefly) for example is used as a reporter gene in many assays. As I only used in single cells I can't say of the substrate oxyluc... | [
"Thanks and very cool! I am familiar with GFP and the use of fluorescence, but it's actually those fish (GlowFish?) that sort of led to the question!",
"A kind of \"why don't we see large bioluminescent transgenic organisms, yet biofluorescent ones are common? (i.e. fish, cats, dogs, mice.)\"\nBut instead of a si... | [
"Okay well I think one of the problems really is the reaction - regardless of possible toxicity of some substrates/ products. \nThe facts that bioluminescent cells need to be exposed to the substrate constantly and also that there is only one photon emmited per reaction (thats why it can be used as a reporter for e... |
[
"If a comet is traveling through space, a vacuum, then why does it leave a 'trail' at all?"
] | [
false
] | null | [
"Comets only have visible tails when they are near the sun. The sun heats up their surface and some gases and dust boil off - that's the tail. It actually points away from the sun. ",
"Like this",
", not out behind like you may expect."
] | [
"The force of the solar wind by definition applies velocity to an object in space. However, when considering the speeds at which bodies move when approaching their periapsis, as well as the masses of the object, the forces applied by solar winds would have no major significance to the motion of the body. However, r... | [
"It isn't leaving a trail in the usual terrestrial sense.",
"As the comet approaches the Sun, it heats up and the various gasses and ions inside it erupt from the surface. These escape the comet and form the coma, the cloud encircling the actual comet nucleus. Some of the ejected debris is lightweight enough to b... |
[
"If you put a TV and it's receiver/aerial inside a Faraday cage would it receive any static or would the screen be blank?"
] | [
false
] | null | [
"There will still be a level of static but it will not be coming from outer space. It will be thermal noise in the electronics. The received noise will be less but still present. You would have to cool down your electronics to absolute 0K (impossible) in order to completely negate all of the thermal noise and then ... | [
"I remember a professor saying that noise in signals is like friction in mechanics: you can mitigate it but you cannot get rid of the problem."
] | [
"That would be an accurate statement yes."
] |
[
"What happens to the food/drinks that \"go down the wrong pipe\" and aren't coughed back up?"
] | [
false
] | As many of us know, humans are bad at eating and drinking. Our epiglottises (?) occasionally fail at their ONE job and let small bits of food or drinks into our windpipe. Often, when this happens, we cough up whatever "went down the wrong way" and it's fine. If it doesn't happen, there are potentially really serious ef... | [
"The upper branches of bronchi to your trachea are lined with ciliated epithelium, little brush-like projections, that beat rhythmically to help get smaller dust and liquid particles mixing with mucous back up to your pharynx, where you hack a bit and swallow them or spit them out. ",
"Anything too big or too far... | [
"That's really cool! Thanks so much!"
] | [
"You got it. The acids, the damage they do to the protective lining of the respiratory tract, and the bacteria involved.",
"The type of pneumonia is known as aspiration pneumonia, and is common in people with dementia who lose the ability to properly swallow."
] |
[
"if we ever run out of copper, for ecample for cables, what's our best bet in terms of price and availability?"
] | [
false
] | null | [
"Aluminum's always an option; plentiful, lightweight, excellent conductor, easily reused. ",
"That said, there are drawbacks. Being softer than copper, handling aluminum wires means they're susceptible to breakage. Aluminum also expands more when heated than copper does, and over time this can work wires out o... | [
"Good explanation and I'll add one more issue - cold flow. Aluminum under pressure will slowly thin itself out, until the connection is loose. This appears to happen even without thermal cycling. Al terminations have to be properly designed and torqued to spec. Periodic thermal scanning or inspection and re-tighten... | [
"Powerlines are usually aluminium now-a-days due to both weight and costs.",
"The fire issues related to aluminium mainly applies to in-house wiring."
] |
[
"In a exothermic reaction how is energy given out to it's surroundings?"
] | [
false
] | null | [
"In an exothermic reaction, the released energy is in the form of kinetic energy of particles in the final state. They heat their surroundings via collisions."
] | [
"Thanks for replying, \ndoes this mean that in order for a exothermic reaction to occur that there must be a adjacent atom or molecule to actually collide and absorb that kinetic energy at the same time the bond is made?",
"Otherwise, if a bond is made and energy is given out, the only place it can give out the e... | [
"Thanks for replying, does this mean that in order for a exothermic reaction to occur that there must be a adjacent atom or molecule to actually collide and absorb that kinetic energy at the same time the bond is made?",
"No. If you have an exothermic reaction A + B -> C + D, C and D carry away the excess kinetic... |
[
"Just Watched Chernobyl Diaries and Was Wondering"
] | [
false
] | [deleted] | [
"Cancer and Infertility are the two most common reactions from being exposed to radiation in the generation that was exactly exposed. In the subsequent genereations though, mutatuions will most likely occur in the from of birth defects and genetic abnomalities. As for whether or not what occurs in the movie is prob... | [
"How about because of the laws of the universe?"
] | [
"And at one point people knew the earth was flat. The closer you get to the speed of light, the more energy it takes to get to the speed of light. So if you are at 99.9999999% the speed of light, you will never reach it because you need an infinite amount of energy to reach 100%. And since we dont really have an in... |
[
"Why aren't more vaccines oral?"
] | [
false
] | It seems a large problem with vaccination efforts is that it requires a trained nurse to deliver the injection. That hiders vaccination efforts in rural underdeveloped areas. So why don't we have more oral vaccines? (If the stomaches acidity is an issue cant we put it in a capsule...or maybe use a hookworm as a vecto... | [
"Keep in mind, Vaccines as they are are very tricky to produce.\nDelicate protein structures or living organism must make it all the way into the bloodstream intact.",
"The human digestive system has a goal of killing or breaking down anything that gets into it.",
"Even in cases where an alternative route makes... | [
"Intranasal vaccination is already being practiced. In 2015 nasal flu vaccine was introduced in UK. And it is getting more and more traction among doctors as a good way of administrating vaccines.\n",
"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2846493/"
] | [
"Intranasal vaccines are an exciting area of advancement in preventative medicine. They do allow for mass immunization programs where compliance and administration are obstacles. Interestingly enough, veterinary science is leading the way in innovations, as the intranasal vaccination of cattle is quite popular (giv... |
[
"Can we just replace our teeth once all of our adult teeth have grown in, like, with real-looking false teeth that never need to be taken care of and won't rot away?"
] | [
false
] | Would it be possible, or economical, if we were to replace our old teeth with, for lack of better term, "super teeth"? | [
"Are you talking for some futuristic cosmetic thing that we would do? Hypothetically? Or are you looking to yank?"
] | [
"Hypothetically, of course. It just got me thinking that dental care is pretty expensive, like braces and fillings. ( I am expected to recieve braces before the end of this month.) Maybe someone should look this sort of thing. "
] | [
"You would still need to floss and brush for at least cosmetic reasons. Food would still get stuck between teeth and at area. Unless of course you completely chanegd the look of the teeth. "
] |
[
"Am I causing myself any harm by heating my food in a plastic container?"
] | [
false
] | null | [
"Heat will thermally degrade some polymers into their constituent monomers and many of them are ",
" carcinogens. You are more likely to melt the polymer than break it down to monomers at microwave heat, however, so it isn't likely there is substantial contamination. Some contain plasticizers like BPA which may... | [
"What type of plastic container are you using? Some have known negative side effects. You can find out by examining the bottom for a recycling number. ",
"This isn't a very reputable site, but it should help a bit",
". I hope this extricates your situation."
] | [
"This is true but also I would like to mention this: it is the dose that makes the poison. Carcinogens exist in many daily items (coffee, for example). I think most of the potential to develop cancer comes from the sun, smoking, pollution poor diet, etc. Cancer can be described as a disease of probability; you coul... |
[
"How Does Evolution Explain Disguised Insects Like These?"
] | [
false
] | null | [
"At a very basic level: if it's hard for predator or prey to spot you, your chance of surviving to pass on your genes is increased (either avoiding being eaten, or being a more effective competitor for resources). I'm sure a much more informative answer will be provided shortly."
] | [
"Thank you Lucifer_Box."
] | [
"Well, on a population level, animals are selected by predators and mates through a process know as natural selection. Animals can only pass on their genes if they can find a mate, and avoid predation. An individual cannot accomplish the feat of natural selection (population level phenomenon). With that being said,... |
[
"How does sun exposure cause skin cancer many years later?"
] | [
false
] | I would have thought that a skin cell damaged by the sun would either immediately produce negative effects, or just die and be replaced. What causes the delay? | [
"For a normal cell to become cancerous, it must develop specific traits through mutation of its DNA - ",
"the hallmarks of cancer",
". One mutation event (such as a sunburn) can cause, for instance, a gene that regulates the cell cycle to stop functioning. This cell then passes this mutation to its offspring ... | [
"The specific mutation mechanism for UV photons is the formation of ",
"thymidine dimers"
] | [
"I've always been told that one sunburn (that blisters) increases your risk of melanoma by some percentage (I believe 10-20%). So I believe that acute exposure carries a higher risk than prolonged exposure. This makes sense if you think about DNA repair mechanisms having some baseline activity - if the repair mec... |
[
"Is there any evidence of anthropogenic climate change prior to the industrial revolution?"
] | [
false
] | Big fat disclaimer: I'm not a fossil fuel apologist nor am I looking for arguments to excuse the current rapid climate change for which we humans are almost certainly responsible. Considering the fact that we can look at ice cores, etc., to makes inferences about past climate trends, I'm curious to know whether there i... | [
"In short, yes, there is discussion and modeling to consider how preindustrial activity, mainly land use changes and/or deforestation, may have started to modify the climate and the extent to which some of those changes are still influencing the industrial era changes more commonly considered (i.e., large scale use... | [
"Here's a related paper that explores the climate effect of indigenous population collapses following European contact in the Americas.",
"Koch et al. 2019. Earth system impacts of the European arrival and Great Dying in the Americas after 1492."
] | [
"Did I read that the plague in Europe killed so many people that more forrests grew and filled in previously farmed fields? Partly causing the little ice age? Or has that been disproven?"
] |
[
"How is it possible for the heat death of the universe to occur when things are always continually interacting somehow?"
] | [
false
] | When I first found out about entropy, the reason why I found the heat death of the universe inconceivable was because of the example of "A sugar cube always dissolves in the tea". If this was to happen to the entire universe, it would have eternity to spend in this fluctual state - so, after an unimaginable number of y... | [
"Entropy is always a tricky subject, but I'll do my best. Entropy is a statistical statement about how spread out or \"useful\" energy is.\nFor example, imagine two tanks of water, a hot one and a cold one. You mix them up and come back an hour later. You will find two tanks of medium temperature water. Entropy is ... | [
"Even if that kind of spontaneous fluctuation happens, the universe will still spend in inconceivable majority of its time in the heat death state, and an insignificant fraction of time in the \"reconstructed\" states."
] | [
"There is no guarantee of a second Big Bang, even given an infinite amount of time (and we don’t know that time is infinite). For starters, we don’t know that another Big Bang even has a nonzero probability. If the probability is zero, it stays zero forever. ",
"Additionally, even with infinite time not all thing... |
[
"What are the neurobiological effects of clinical, chronic depression on the brain?"
] | [
false
] | All mental illness seem to come back to physical abnormalities/deformities in the brain, which explains why people can't just snap out of there various stats. What specific neurological abnormalities/deformities appear to account for chronic depression? | [
"The thing to keep in mind is that depression is a remarkably complicated condition. Beyond the mood-related symptoms, depression can also be marked by difficulties with sleep, appetite, information processing, and attention. Making this even more complicated these symptoms can go in both directions. For example, t... | [
"I've reading a lot on the neurological architecture of various mental illness lately, so this made a bit if sense. If I read this correctly, it's similar to how the brains of those with BiPolar have some 50 regions/circuits that are affected on a spectrum. Maybe regions 3-40 are totally normal on person A but re... | [
"It is very possible that there are different causes for the symptoms we currently group together as depression. But its also important to note that bipolar and depression are distinct conditions. Grouping together people with depression and people in a \"depressive\" phase of MDD has led to a lot of confusion in t... |
[
"What is the point of using specific gravity?"
] | [
false
] | In my pharmaceutics course/lab I see a lot of density measurements expressed in "specific gravity". I understand that Specific Gravity is the density of a substance in reference to a "benchmark" substance, but that "benchmark" substance is normally water, which is 1 g/mL. So my question is, why bother having a unit of ... | [
"Hello,",
"In thinking about it, and racking my brains, and a spot of research :",
"While specific gravity is indeed similar to density, its not quite the same - the concept of specific gravity is that it is ",
", so not dependent on a single unit of mass or volume.",
"However, it is also a ",
" measure :... | [
"In my courses on soils, I've seen specific gravity used a lot, typically to define the density of a given soil. My understanding is that it's a simple way to compare soil densities, and can be easily understood by those using any units (since it's relative)."
] | [
"By having the unit dimensionless, we easily can see the relative density of the substance to water.",
"ie SG of 3 is 3x denser than water, which is an easy factor to use",
"Why not density?",
"3g/mL would be the equivalent density, but how many times denser than your medium is this? it's not 3g/mL, it's 3...... |
[
"Is the Raman scattering process more likely for symmetric molecules than asymmetric ones?"
] | [
false
] | For example, I am measuring iso-pentane and normal-pentane (at the same concentrations) and I can't figure out why the the raman shift intensity for iso-pentane is lower than that for normal-pentane. Any ideas? | [
"This is a deceptively deep question that has to do with spectroscopy selection rules. If you google \"Raman scattering selection rules\" and take a look at some of the results you'll learn a lot.",
"In this case there's a complimentary distinction between IR spectra and Raman. In a very crude sense, because of t... | [
"Group theory is actually quite beautiful, because it can lead to very simple explanations for very complex problems in physics."
] | [
"Peak intensity is proportional to the number of representations that are raman active (populations) as determined by the character tables for a given molecule. Character tables are derived from the possible symmetry elements a given molecule possesses (matrix math and a lot of playing with models) which then revea... |
[
"Why do people tend to get fatter around when they become middle aged?"
] | [
false
] | null | [
"It's mostly due to exercising less and eating more. An increase in \"sedentary behavior\" has perhaps the biggest effect.",
"details:",
"Study after study has documented a slow, seemingly relentless increase in body fat as people go from age 20 to age 60. See ",
"here",
" for example - kind of a depressing... | [
"i've read that in more than one place that this what is actually happening is due to reduced activity and not reduced capacity. Looking around at my friends as I approach the big four-oh, this seems to be the case for them."
] | [
"Then the question becomes, why do people lose the ability to balance their energy consumption with their energy expenditure when they get older?",
"The BMI of humans in their natural environment (hunter-gatherer societies) does not usually increase with age. Is there something in the modern environment that prog... |
[
"Do photons exert gravitational pull on other photons and objects with mass?"
] | [
false
] | [deleted] | [
" Yes. Photons contribute to the curvature of the universe because they have ",
", and if you have enough of them you can even make a black hole!",
" Photons, while massless, still have energy. That energy contributes to the energy content of the universe (mathematically, by the way of a thing called the Electr... | [
"Photons don't have reference frames, and it is important to know why. In an inertial reference frame, all the laws of physics hold true, including the finite speed of light. If photons did have reference frames, then they should see other photons going at the speed of light relative to them, but the photon is alre... | [
"1) Photons are always moving at the speed c, in all reference frames.",
"2) An object is not moving in its own reference frame.",
"3) If a photon had a reference frame, it would be both standing still and moving at c, in that reference frame. Which would be a paradox."
] |
[
"Is there a syndrome that describes the sensation of hearing people who aren't really there?"
] | [
false
] | [deleted] | [
"A syndrome actually means multiple symptoms that concur together that suggest a common pathological cause. What you're describing is either an auditory illusion or an auditory hallucination. ",
"An auditory illusion is an audio misperception of reality; for example, a squeaky door that you think is a cat is a ha... | [
"Unfortunately the differential diagnosis for auditory illusions/hallucinations is incredibly broad, ranging psychiatric illnesses, to endocrine disorders, to even things like trauma and toxic exposures. This might be something you'll want to bring up with a primary care physician/general practitioner."
] | [
"If you're really concerned, you can go check it out with a doctor. An imbalance in the functions of your neurotransmitters can be accountable for all kinds of strange experiences, which might seem like hallucinations. If you have any other symptoms, you should definitely go to a doctor, but I've never heard of any... |
[
"Order, disorder and complexity: how do we choose an order parameter?"
] | [
false
] | My research involves looking at statistical systems in physics and comparing them to brain functionality. The concept of an order parameter is very essential when one wants to analyze the system and look for phase transitions. I understand that order/disorder are generally defined by low/high entropy limits, but one al... | [
"I don't think there exists a formal algorithm for finding order parameters in systems. However, you might want to look into spontaneous symmetry breaking. Generally speaking, the more disordered phase has a larger symmetry group which leaves it intact, while the ordered phase usually has a subgroup of the disorder... | [
"Unfortunately the order parameters in a system can be very difficult to find in general. Take one of the most famous phase transitions, the liquid-vapor transition in water. The gas and liquid phases have the same symmetry, but it turns out that the critical point is in the same universality class as the Ising mod... | [
"but ultimately it has to do with symmetry breaking right?",
"No, it doesn't have to be related to symmetry breaking. The fact that the liquid-vapor critical point has a line which has behaves like the Ising transition is an emergent phenomenon related to how systems simplify close to their critical points, resul... |
[
"Ask Anything Wednesday - Physics, Astronomy, Earth and Planetary Science"
] | [
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! ... | [
"Remember that atmospheric pressure is not much. You are currently experiencing 1 atm of pressure and you have no problems with it. The ISS has an internal pressure that is equal to 1 atm. Outside the ISS, in the vacuum of space, the pressure is 0. The pressure difference between space and the inside of the ISS is ... | [
"Regular atmospheric pressure is quite strong though. It feels weak because you're completely used to it, but it effectively means that you have over a kilogram of force being applied to your eye right now due to atmospheric pressure. Put 5 mbar of pressure difference behind a door, and there's no way you're going ... | [
"This is something I’ve always wanted to know;",
"Mostly curious due to NASA’s moon base plan, how do we keep a structure pressurized against the vacuum of space for such a long period of time? Is there a deterioration or maintenance process that would need regular up-keeping? Furthermore, In the vacuum of space,... |
[
"What would have happened if the “demon core” was left to go Supercritical?"
] | [
false
] | null | [
"What I’m curious about is, what would have happened if the Demon Core was left to go supercritical?",
"It was. Human intervention is not what stopped the chain reactions. The system has a negative temperature coefficient of reactivity, meaning that when it became supercritical, it heated up, and the increase in ... | [
"what I meant was what if it was just left there, with nobody to stop it.",
"Yes, that's the question that I answered. There's no difference between somebody stopping it and it being left alone, because it stopped itself faster than anybody could grab it."
] | [
"Yeah I know it went supercritical; what I meant was what if it was just left there, with nobody to stop it."
] |
[
"How to identify intron sequences in mRNA?"
] | [
false
] | How do I find the exact place where the intron starts and ends in an mRNA sequence? Thanks in advance! | [
"Introns are removed by a ribonuclear complex called a splicesome that recognises motifs called a splice donor site (at the 5' end) and a slice acceptor site (at the 3' end). About 50 nucleotides upstream (before) the acceptor site will be a branch site that is important in excising the intron.",
"What you need t... | [
"If you are interested in predicting splice sites within an RNA, there are a number of computational approaches that try to search for sequences that fit splice criteria (as Hashshashin7 pointed out). These are not always accurate, since the sequence of the acceptor and donor can be pretty degenerate, but the scor... | [
"It would largely depend on the organism that the mRNA was derived from. While RNA splicing is found in most eukaryotic organisms, predicting introns within an ORF can depend on the organism and sometimes the tissue. Prediction software (such as NetGene2, which I linked) can usually identify potential splice site... |
[
"What happened to locust swarms in the US? They were once a major issue and then just seemed to stop, what happened in the US that led to this disappearance when they are still problems elsewhere around the world?"
] | [
false
] | Reading historical works, locust swarms seemed fairly common in the US and then just stopped. Is there a scientific consensus as to what caused this decline? How is the US different than other areas of the world that still experience locust swarms? | [
"This is a neat question! As it happens, North America is currently the only continent (besides Antarctica obviously) without at least occasional major locust swarms. And the reason for this is because we killed them all! The predominant locust species in North America used to be the ",
"Rocky Mountain locust"... | [
"That's a pretty inaccurate view of the world. Mosquitos and wasps include thousands of species and both are ecologically important groups of organisms as pollinators, predators, and food sources for other species. Meanwhile, honey bees (the only species of bee that is bred by humans on a large scale) are introdu... | [
"Now if only a complete eradication happened to mosquitos and wasps, and hornets. Nature doesn't need that pile of worthless creatures.",
"After that, breed more friendly bees."
] |
[
"What does it mean for a quark to have 'Spin'?"
] | [
false
] | I've read up on this before but I've never truly understood elementary particles having spin. What basically is it? | [
"I'm not sure I can give you a satisfying answer, but I'll explain it the best way I can. Elementary particles have angular momentum that is completely separate from any motion the particles are undergoing. This angular momentum is in the direction that would come from the particle spinning about some axis, but it ... | [
"Ultimately, these are all mathematical constructs and don't really have a neat intuitive analogy with things with which we're familiar. What they really ",
" is what the math says they are."
] | [
"Colors aren't forces. They're charges.",
"You know electric charge, right? It comes in two flavors which we call positive and negative. Electrons have one unit of negative charge, protons have one unit of positive charge. Some things, like neutrinos, have no electric charge at all, either positive or negative.",... |
[
"If I'm on the interior surface of a rotating cylinder in space, I'll feel something that I could interpret as \"gravity\". Is it possible to spin a cylinder fast enough to create an \"event horizon\" on the inside?"
] | [
false
] | null | [
"Basically, ignoring material constraints, is it theoretically possible to make it so that centrifugal force creates an \"escape velocity\" greater than C?",
"No. The \"gravity\" you are talking about would be caused by the accelerated circular motion of the cylinder walls. The walls would have to move faster tha... | [
"Are you assuming that your acceleration is equal to C? I don't understand the logic behind that. The units don't match.",
"But think of it this way. The light always moves at C. Therefore, to prevent the light from moving from the periphery towards the center, the wall needs to \"carry\" the photon tangentially ... | [
"I don't understand why the cylinder walls would have to have a velocity greater than c. Centripetal acceleration is a=v",
" /r so with a r of 1 v would be the square root of c."
] |
[
"does wearing darker coloured NFL jerseys actually have an impact in the heat?"
] | [
false
] | I learnt a long time ago that some NFL teams often opt to wear lighter coloured jerseys in warmer situations (i.e. Carolina, Jacksonville & San Diego will wear light colours to make their opponents wear dark colours). I understand the theory behind this, but does it actually make a significant difference? i've also see... | [
"Yes -- assuming the visually dark colors are dark in the infrared (usually true). And the effect is that dark colors absorb more direct sunlight, but they also radiate more body heat into shadows or any environment with a temperature lower than body temperature.",
"In other words, dark colors are a two-way stree... | [
"If you would care to do an experiment. On a hot day wear all white if possible but at minimum a white shirt. Stand outside for an hour just doing stuff, not anything too physical.",
"Then go outside and wear all black if possible, but again a black shirt will do. Then do stuff at equal intensity and make sure... | [
"I dunno how you define \"significant effect\", but darker clothing DOES absorb more light, which makes them get hotter. You can test this yourself by putting a white shirt and black shirt outside and feeling the difference in their temperature after half an hour.",
"I wish I could do an energy calculation for yo... |
[
"Why is Force equal to the differentiation of Kinetic Energy with respect to displacement?"
] | [
false
] | [deleted] | [
"*Potential energy"
] | [
"http://hyperphysics.phy-astr.gsu.edu/hbase/pegrav.html"
] | [
"http://hyperphysics.phy-astr.gsu.edu/hbase/pegrav.html"
] |
[
"Why does the atomic mass of nuclei change during fusion and fission?"
] | [
false
] | I know that the combined mass of nuclei change when fused or fissured. This releases energy according to E=mc But why does the mass change when the number of protons and neutrons stay the same? | [
"Atomic nuclei are held together by an amount of nuclear binding energy. In order to form a nucleus from scratch, you not only have to put all of the protons and neutrons together but also insert an extra amount of energy to bind it together. This energy creates a difference between the sum of the constituent masse... | [
"Fission: ",
"1: Potential energy inside the nucleus is converted to kinetic energy of nucleus parts. Mass of potential energy is converted to mass of kinetic energy.",
"2: Kinetic energy of aforementioned parts is converted to kinetic energy of some other particles in collisions. Mass of kinetic energy is conv... | [
"This difference is (delta)M = (binding energy)/c2 .",
"The watchful eye will probably spot that this is Einstein's famous E=mc² equation right there. That's where the notion of energy and mass being equivalent can be directly seen."
] |
[
"Are there any significant (or minor I suppose) issues with the theory of evolution?"
] | [
false
] | I know that this film was basically made out to be bullshit. But in Expelled: No Intelligence Allowed they made claims that there are key problems with evolution, however they never cited any problems. So I thought I would it. | [
"At the very heart of it, the answer is no. The theory of evolution is one of the most tested and best supported ideas we have in biology. One famous quote is given as, \"Nothing in biology makes sense, except in the light of evolution.\" -Dobzhansky.",
"Now, within the evolutionary field, there are many issues... | [
"straight from wikipedia",
"The formal scientific definition of theory is quite different from the everyday meaning of the word. It refers to a comprehensive explanation of some aspect of nature that is supported by a vast body of evidence. Many scientific theories are so well established that no new evidence is ... | [
"These claims generally arise from lack of knowledge about Evolutionary Theory. The first claim is that we can't fully explain the origin of life yet. This is irrelevant, since evolution does not deal with the origin of life, only how it changes once already established. The only other claim I've heard off the t... |
[
"Scrubbing off rust with Aluminium"
] | [
false
] | I was told by a friend today that you can clean rust of metal by scrubbing it with household aluminium foil. Skeptical but willing to give it a go, i scrunched up some foil and started rubbing the rusted areas, and sure enough, off came the rust. While scrubbing i wondered: What's the chemistry behind this? | [
"I would suspect that the layer of aluminum oxide, also known as corundum, on the surface of the aluminum metal provided the necessary Mohs scratch hardness to remove the iron oxide."
] | [
"Err... Doesn't iron + aluminum essentially give you thermite? "
] | [
"I'll set alight the foil I used and let you know"
] |
[
"Why does covid hit overweight people harder ?"
] | [
false
] | Title basicly. Is it related to the lipids making it easier for it to reproduce ? Or is it their immune system as fast foods are both related to lower immune responses and well, gaining weight as well ? If y'all have videos I love to watch that too :) Edit : no clue why I keep getting downvoted, perhaps its my bad engl... | [
"Obesity causes immunosuppression, through chronic low-grade inflammation, and makes people more susceptible to infections:",
"recent findings have highlighted the substantial impact that obesity and MetS parameters have on immunity and pathogen defense, including the disruption of lymphoid tissue integrity; alte... | [
"There aren't this many. There are way more than that. If you're overweight, getting into shape is the best thing you could possibly do for your health, especially in the typical case where its also combined with a lack of exercise."
] | [
"Thank you for taking the time to source so much stuff and to answer so very well ! I didn't know there were this many downsides to being overweight."
] |
[
"If out of the total population on earth, 10% of the people are left handed, why are athletes who are left-handed so disproportionate than the general population?"
] | [
false
] | In most sports team I've observed there are approximately 20% of athletes who are left handed. Why is this proportion larger and what chances are there of the total 10 % interested in sports? | [
"Because right handed people are less practiced at dealing with their left handedness than left handed people are with dealing with most every one else's right handedness. It gives them a competitive advantage."
] | [
"Especially in boxing, where your southpaw opponents movements are a complete reversal of what they've spent their whole lives getting used to."
] | [
"20% of athletes are left handed. ",
"Citation needed."
] |
[
"Why do Airborne Nuclear Detonations Cause EMPs and are the effects to electronic devices permanent?"
] | [
false
] | would electronic infrastructure need to be replaced or would the effects "wear off"? | [
"Radio and microwaves create currents in conductive objects. This is how radio antennas pick up signals and why forks tend to melt in the microwave.",
"The bright flash of x-rays from the bomb will send a very large number of electrons in the upper atmosphere recoiling at once, producing a very sudden and sharp b... | [
"Airbursts emit more EMP because the heat capacity of air is quite low. All of that energy can ionize the air into plasma, but because there's so little density to absorb energy, much of the energy will dissapate in the form of electromagnetic radiation.",
"Underwater or under ground, there's quite a lot of dense... | [
"Need to be replaced... Components get fried by the pulse. They can be shielded, but that adds weight and expense.",
"We had lightening strike a tree across the road a few years ago. Even though our TV was unplugged because we saw the storm coming, it still died."
] |
[
"Does dissolving one thing in water make dissolving another thing in water more difficult?"
] | [
false
] | Like, if I add a bunch of salt to water, then try to dissolve a certain amount of flour, will the amount of flour that I am able to dissolve decrease compared to 'clean' water? A 'yes' or 'no' would be appreciated, but if you can get into the chemistry a bit , that would also be interesting. :D | [
"For ideal (dilute) solutions the answer is a qualified ",
". ",
"How much of a salt will dissolve in water at a given temperature only depends on the concentrations of the constituent ions and the disassociation constant of that salt (often called the K_{a} of that substance). The chemical equation for the dis... | [
"This answer has the perfect level of detail! Thanks a bunch!"
] | [
"Yes. When you dissolve salt, the sodium and chlorine ions disperse throughout the liquid, between water molecules, and take up space. If you put too much salt, the solution becomes saturated as there is no more space between water molecules so it doesn't dissolve any more. In a salt water solution, there is alread... |
[
"are there any mushrooms/fungi that live underwater?"
] | [
false
] | null | [
"There’s more than 400 species of fungus that live underwater in various marine habitats but underwater ‘mushrooms’ are rare. Psathyrella aquatica is the only mushroom that I know of that thrives and will fruit underwater. ",
"https://www.researchgate.net/publication/269552443_Psathyrella_aquatica_Fruiting_in_... | [
"According to Penn State, “Mushrooms respire: they take up oxygen and produce carbon dioxide.” Hard to do underwater without gills. ",
"https://news.psu.edu/story/140841/1997/09/01/research/no-more-mush-mushrooms",
"ETA More info here about how hyphae (the little filaments in the soil that terrestrial fungi use... | [
"i wonder why so few fruiting bodies!"
] |
[
"How common is incest in mammal populations? What impact does it have on their evolution?"
] | [
false
] | I've learned that humans are "programmed" to seek mates that look similar to us, but not similar. Is this the case with other mammals? Does inbreeding provide for more genetic oddities that could produce beneficial mutations, or is it generally a path to failed populations? | [
"You're right in saying that humans look for similar mates. This is because mates that are too foreign bring with them traits that are less well adapted to your environment which can result in an increased likelihood of death ( A process called ",
"). We don't want mates that are too similar though and humans do ... | [
"Devils are not, for the most part, inbred, despite what that headline says. People seem to constantly confuse lack of genetic diversity with inbreeding but they are two different things. Inbreeding means that the individuals have higher homozygosity than would be expected by chance in the given population, due to ... | [
"An interesting case study for this would be Tasmanian Devils- inbreeding is generally a pretty big issue for them, and as a result, a specific kind of cancer was able to rapidly spread between them because of the lack of genetic diversity. At one point they were considered to be near extinction, because the diseas... |
[
"Necessity of a Mars suit?"
] | [
false
] | As temperatures on Mars seem to be not too different from what you'd find on Earth's polar regions, wouldn't extreme cold weather gear and a pressurized breathing helmet be sufficient? My guesses why not: - Atmosphere insufficient to achieve the same insulation effect terrestrial cold weather clothing relies on - Low a... | [
"The atmospheric pressure of Mars isn't just low- it's REALLY REALLY low (0.087 psi average). It's basically a vacuum. Water above 80F will boil spontaneously. Your body is above 80F. Gas bubbles will form in all exposed liquids, causing death in a matter of minutes. ",
"On Earth, pressures below 10psi are v... | [
"The dust found on Mars' surface contains carcinogens and razor sharp particles, meaning protective gear has to be worn as well."
] | [
"Also no global magnetic field or ozone layer will require protection from solar radiation."
] |
[
"How does this product work?"
] | [
false
] | [deleted] | [
"As long as it was not conductive once dried there would be no problem applying a liquid to a circuit board that is not plugged in.",
"The only problem I could see would be changing the thermal characteristics of the board."
] | [
"An extreme example of this is submerged, oil-cooled computers; like KaneHau says, as long as the substance is non-conductive it doesn't pose a risk to the electronics."
] | [
"And by their nature, hydrophobic materials tend to be non-conductive. The oil used to cool the computers you speak of is in fact hydrophobic.",
"To be hydrophobic, the material has to resist polarizing, and therefore resists forming polar bonds with water (ie wetting). Not polarizing also means it won't carry ... |
[
"After death how long do processes like digestion or cell regeneration continue to go on and what ultimately stops them?"
] | [
false
] | I would imagine that the processes don't stop immediately. | [
"In short, what ultimately stops cell processes after death is lack of oxygen. Without oxygen ions to fix electrons on the cellular level, cells are unable to function or reproduce, and they begin to decay. ",
"For some cells that require constant oxygen (such as neurons) this can happen almost immediately (withi... | [
"A drop in body temperature from submersion slows the body's metabolic processes, thereby prolonging cell and tissue preservation. ",
"Therapeutic cooling is used in hospitals on witnessed cardiac arrests as soon as they enter the ER, for just this reason. ",
"Edited to add: four hours is a stretch, though, in ... | [
"What happens when you hear about people who have fallen into a lake and are dead for 4 hours then revived? How do the cells survive without oxygen?",
"Edit: As others have noted it's not 4 hours. The longest incident I could find was 80 minutes. Still interesting.",
"Edit 2: Doctors induced hypothermia in t... |
[
"Why is The Seven Bridges of Königsberg such a famous question?"
] | [
false
] | I'm not a mathematician, but to me the solution is fairly obvious and uniteresting, compared to other famous mathematical riddles. | [
"Solution is faulty obvious, the proof of said solution isn't trivial. It's still fairly straightforward but some of the steps of Euler's proof lead to the development of graph theory and topology, and that's why it's viewed as an important problem.",
"Here's some reading if you're interested: ",
"http://www.ma... | [
"Would you mind sharing your obvious solution? Seriously!"
] | [
"The answer is obvious today because we have the techniques of modern mathematics, but in Euler's time, there was no graph theory, and the solution was not obvious at the time. It's famous because it led to the development of a new field of mathematics"
] |
[
"Is there a relation between color blindness and reaction time?"
] | [
false
] | null | [
"We are actually very bad at detecting movement of objects that are the same brightness as their background (i.e. defined by color differences alone). ",
"I'm not quite sure what you are trying to ask here -- colorblind individuals will be worse at tasks that require them to use color information that they can't ... | [
"Essentially:",
"What is the reaction time of a color blind individual to a sudden change that is easily visible due to difference in brightness?",
"How quickly does a color blind individual notice subtle movement in the background compared to someone with average sight. (Both with high difference in brightness... | [
"If by sudden change in brightness you just mean that a white light goes on, then there is no difference -- that is detected by the rod system and not by cones."
] |
[
"[Biology] DNA in the Mitochondrion makes little sense to me"
] | [
false
] | It is said that Bacteria DNA is in the Mitochondrion but I dont understand how that DNA is able to be in every new Human. When a cell does mitosis or a germ zell meioses what happens that the bacteria DNA in the mitochondrion is in the next cell. | [
"Mitochondria divide in a manner similar to bacteria (fission) (from the wikipedia article that you linked). You can read more about it here: ",
"http://www.nature.com/scitable/topicpage/mitochondrial-fusion-and-division-14264007",
". So, you can almost think of the mitochondria as being similar to smaller c... | [
"laflavor has it correct above. to try to put it in simple terms...",
"Mitochondria have their own dna.",
"The current hypothesis is that mitochondria are essentially \"little bacteria\" that have symbiotically adapted to living inside eukaryontic cells.",
"They recreate and divide on their own to some degre... | [
"Adding on a bit more here.",
"Each child gets his mitochondria only from their mother. Since sperm carries no organelles, all the mitochondrial DNA you have all came from the few mitochondria that were in the egg from your mother. ",
"EDIT: silly me, sperm do have mitochondria but they are not passed on to the... |
[
"Where does energy come from in an explosion?"
] | [
false
] | For example, I was watching Nova's Doc. Hunting the Elements and they were explaining how combustion works with nitrates (loosely): when heat is introduced to nitrates, bonds are broken, and the atoms split up and bond with other 'preferred' atoms creating compounds like H2O, CO2, and O2. But where does the energy that... | [
"The energy that is released comes from energy that was spent to form the explosive, combustable compound in the first place."
] | [
"The chemical reaction in question is exothermic. So, indeed, the gas are hot (which increases the pressure), and may ignite."
] | [
"Typically, lots of gas (N2, H2 and CO in the case of TNT) is created in a very small amount of time. That gas then proceeds to expand very rapidly."
] |
[
"What will dehydrate you faster; A wet heat or a dry heat?"
] | [
false
] | Assume same everything (sunlight, temperature (let's say 105F), body condition, personal stamina, etc.), except one location is dry and the other humid. Would there be a difference in the rate of dehydration? | [
"In a situation where rigorous physical activity is involved, evaporation of sweat from the skin serves as the primary method of heat loss from the body.",
"In high-humidity [wet heat] situations, evaporation of sweat is limited, reducing the body's ability to lose heat. The body will continue to attempt to regu... | [
"I think you also need to take into consideration that in a wet heat, you will regain/not lose water while breathing. So while you may be sweating more to attempt to regulate body temp, you are not losing water via exhalation. While in a dry heat, every breath you exhale also takes with it moisture from your lungs.... | [
"Interesting. I wonder if there is a Bear Grylls solution to that if caught in a desert?"
] |
[
"Why do we genetically engineer E. Coli instead of other bacteria?"
] | [
false
] | Is it just easier to grow and modify compared to other bacterium? | [
"E.coli is widely used because it is well known and easy to grow, as others already pointed out. But it is not alone. There are A LOT of other bacteria equally easy to work with and both Bacillus subtilis and Lactococcus lactis are fairly common model systems.",
"Now, one reason why people tend to stick to E.coli... | [
"The tools don't always transfer to other organisms. For example, if you want high/medium/low expression, you might make a plasmid and choose different 'origins of replication' on that plasmid, which only work in ",
". Then, if you want inducible expression, you'd use the Lac operon, which is recognized by the ",... | [
"I don't have too much experience with biochemical techniques, but E. coli is pretty easy to grow (the protocol I learned required about 10 hrs of growth), and therefore a good host to do your protein expression. However, I do know other labs who used insect cells, which are even more hardy, but they take longer (m... |
[
"If I pushed a rod that was one light year long, would a person at the other end of the rod see it move at the same time I pushed the rod?"
] | [
false
] | null | [
"The push will propogate at the speed of sound in the rod, which is (for a real rod) less than the speed of light. "
] | [
"The sound propogates through the rod itself."
] | [
"Edit: Never mind, I know how it works. The material that the rod is made out of determines the speed of sound. Thanks for the answer."
] |
[
"What would happen to a floating helium balloon if it did not burst in the atmosphere?"
] | [
false
] | In lieu of this picture from the front page: | [
"The buoyancy of the air around the balloon decreases as the air thins out at high altitude. Eventually the balloon will settle at an altitude where this exactly balances out gravity, but no more."
] | [
"There is a lot of scientific research done in the upper atmosphere with the neutral buoyancy principal. NASA, for example, has balloons that will stay at approximately their target altitude for 100 days with payloads as big as 3600 pounds!",
"Sometimes the balloon doesn't even pop from wear but instead is popped... | [
"Just for scale, escape velocity 50 km up is still 99.6% of escape velocity at ground level. "
] |
[
"If the earths inner cores are made up of magma, does this magma slowly erode at the earths crust from underneath?"
] | [
false
] | I know magma rises through a volcano vent and such, does the magma erode at our from beneath? If so is it substantial? Also does the ratio of crust and other cores change much? | [
"No significant part of the Earth is 'made up' of magma. ",
"The inner core is solid. The outer core of the planet (located between roughly 2900 km to 5100 km beneath the Earth's surface) is the only significant layer which is liquid (primarily iron/nickle), but this is molten metal and not technically magma. It ... | [
"Core and mantle have different compositions so make different solids having different melting points; one is liquid while the other solid at the very same conditions. This is not at all the same as when a hot silicate magma rises upward into crust of similar composition (but colder in temperature), which does ten... | [
"also relatively dense and the only major exchange between the outer core and the mantle (which overlies the outer core) is of heat. This heat does serve to produce magma at this boundary, but not as much as you might think",
"It’s still up for debate whether there is any partial melt generated at all at the core... |
[
"How does fluid loss affect cognitive ability?"
] | [
false
] | Earlier, I saw this TIL in : Sports studies have underlined the importance of fluid level in the body. A person who has lost 4% of body weight can lose up to 40% of their psycho-physical ability. However I can't find a source that shows this 40% figure, and I only found that talks about cognitive ability loss after deh... | [
"In simple terms, your brain needs two things for survival: glucose and oxygen. This is carried and transported by the circulatory system. When the human body experiences an event such as a high concentration of g forces, it cause blood to leave the brain. Also the reason why fighter pilots wear a g suit when doing... | [
"Alright. But how do they quantify the loss in cognitive functions? Glucose levels?"
] | [
"Alright. But how do they quantify the loss in cognitive functions? Glucose levels?"
] |
[
"What prevents prions from being used as a biological weapon?"
] | [
false
] | After reading a bit about prions (i.e., the cause of afflictions like Mad Cow Disease), I am really disturbed. There is no cure for them, and they are seemingly resilient. What prevents their mass transmission, and are they susceptible to being used as a biological weapon? | [
"Most of those who do eventually develop spongiform encephalopathies do so after several decades post-exposure. It is not certain how likely you are to develop the disease if exposed, and it is not transmitted between people (who aren't brain eating zombies). In short, it would make a terrible biological weapon. D... | [
"Prions are not transmitted by any method we know short of consuming the infected material. This makes them a very poor choice, as you'd need to consume them to get ill.",
"They're also latent, they do not provide reliable disease progression, it can take many years for an infected individual to show symptoms an... | [
"Prions are not living entities, they're proteins. They also only exist in very specific areas of the host they infect. This means that if you have these proteins and cough, you're not spewing infected proteins on people as they aren't present in your lungs. This makes airborne transmission from person to person... |
[
"Can the human acceleration limit be worked around?"
] | [
false
] | [deleted] | [
"Magnets won't work for this, however the idea of accelerating the whole body evenly is the right solution, though there is no practical way to do that yet.",
"\nRight now what can be done is immersing a person in body-density liquid, this will increase the G-tolerance to an estimated 15~20G; if the person's lung... | [
"Here is perhaps the only research on humans in controlled, very high g situations:\n",
"http://en.wikipedia.org/wiki/John_Stapp#Works_on_effects_of_deceleration",
"\"Stapp demonstrated that a human can withstand at least 45 g (440 m/s²) in the forward position, with adequate harness\"",
"That is for a brief ... | [
"If the whole body were evenly accelerated, is it true that we would not have the sensation of acceleration (we would feel the same as being in free-fall)?"
] |
[
"Is there any physical way to stop cosmic rays?"
] | [
false
] | null | [
"You can put it very deep underground to lower the cosmic ray background."
] | [
"But is that because of height or because of the rocks/dirt surrounding the place acting as an \"armor\"?"
] | [
"because of the rocks/dirt surrounding the place acting as an \"armor\"?",
"Yes, it's just the huge amount of material to shield them."
] |
[
"Do we currently have the tech available to give someone a one-way ticket to mars?"
] | [
false
] | I understand that new stuff would have to be invented, so by "having the tech" I mean that we aren't inventing a way freezing and then reviving the person when they get to mars. Or we aren't relying on unobtainium to create the ion-blaster rockets. In otherwords, is the tech readily available and "easy" to do given eno... | [
"Are you thinking of something like ",
"Mars to Stay",
" one-way missions?"
] | [
"Really, I'm only thinking about the getting there and the landing safely part. I'm wondering if we could do even that much right now. I realize that coming back home will just about double the amount of fuel the ship needs to carry."
] | [
"There is a big difference between \"tech\" and \"ability.\" We have the technology, but we do not have the manufacturing capability (currently). "
] |
[
"How do rocket scientists ensure that a rocket's mass distribution is balanced throughout a launch?"
] | [
false
] | I've been playing a lot of Kerbal Space Program (game where you basically run a space program), and I always need to make sure that my launch vehicle (rocket) is either incredibly balanced, has control surfaces to compensate, or the magic reaction wheels. Otherwise my next stop is the ground, not orbit. Considering the... | [
"One key consideration is in the \"balancing\", as you said, specifically placing the differing parts of the payload, propulsion, control systems, and other components to move the entire vehicle's center of gravity forward of the center of pressure (where the lift forces are resolved). Ideally you want the center... | [
"They use hydraulic actuators on the larger engines (like the J2X) and mount them straight to the combustion chamber (where the fuel and air mix and ignite), meaning that most of the \"rocket motor\" is on this gimbaled system, but the force is not just on the actuators, but the entire system exists in a frame that... | [
"In the case of the gimbal system, I've always wondered how the gimbals manage to move something that carries so much force, fast and precise enough to actually counter any disturbances. How does that work?"
] |
[
"All time zones converge at the earth's poles. So for scientists working near either the north or south poles, what time zone do they actually use?"
] | [
false
] | Another way to say it: what time/date is it at the location of the north and south poles right now? How did scientists determine this time/date as the official time to go by at the poles? | [
"At the Amundsen–Scott South Pole Station, they decided to use New Zealand time (UTC +12), because all official travel to the station comes to Antarctica out of Christchurch. ",
"Since the North Pole is an iceflow in the Arctic Ocean, it does not have a permanent settlement that would require them to figure out a... | [
"Interestingly, if you were to travel around Antarctica you would go through quite a few different time zones. Pretty much every country that has some sort of claim down there has their respective territories on a different time. "
] | [
"Aha! There was actually a really neat BBC story about this a few weeks ago. Here's the link:",
"http://www.bbc.co.uk/news/world-12849630",
"Go to the article called \"What time is it in Antarctica?\" The video is great."
] |
[
"Within a population, can vaccinated members ever be put at health risk from non-vaccinated members?"
] | [
false
] | Simple Scenario: 10 organisms of the same species in a confined setting. 7 are vaccinated for virus X, 3 are not. Expose virus X to the entire population. The 3 are positively infected with virus X. Are the 7 vaccinated members at any risk from being around the infected 3? How would this scenario apply to vaccinations ... | [
"The three can still infect the seven uninfected individuals as vaccinations are not a 100% effective. Vaccinations increase the likelihood that you will not contract a disease by building up your immune system to fight off any real infection.",
"In regard to your question of interest, if Virus X was introduced ... | [
"I think the analogy is apt. Vaccinations allow the body to create a stockpile of memory cells; they build up the immune system, making it more able to quickly respond to future infection. "
] | [
"if you mean \"herd\" immunity, i don' think it applies to my question. I'm asking how the 3 could affect the 7, not how the 7 could affect the 3."
] |
[
"Can someone explain histamine to me, and why so many people have too much?"
] | [
false
] | Okay, I understand a bit about histamine - it triggers allergic responses (H1), stomach acid production (H2), and affects libido and mental processes (possibly even a contributor to schizophrenia). The only positive I've found is that it helps erectile function & libido. Aside from this, what's good about histamine? Wh... | [
"Right, well seeing as I am occasionally credited with discovering the histamine H4 receptor in the brain, I suppose I should take this one. HOWEVER, I am not even close to being an expert on the immune system and allergies.",
"So your first mistake is assuming that histamine is to blame for allergies, while it m... | [
"It starts back before the mast cells.... Exactly why I don't know... I'm not sure anyone does (though as I say, not an expert on these things). But the problem is that your body is making the antibodies against things it \"shouldn't\"... whether that is pollen or whatever. Then the mast cells pick them up, and by ... | [
"Thanks for the great response!",
"So then, would it be correct to say that people who have allergy issues have overly sensitive mast cells?",
"\nOr, does it start back with the T cells or B cells or earlier in the chain? Can anything be done to desensitize things, or would that likely create other problems?"
] |
[
"If energy can neither be created nor be destroyed where does all the energy in the universe came from?"
] | [
false
] | If energy can neither be created nor be destroyed where does all the energy in the universe came from? | [
"1) The energy of the universe could be zero, as already pointed out.\n2) The law of conservation only states that energy is a constant, the actual value of that constant could be anything so even if the energy has a net positive or negative energy, that's not a problem at all.\nEven worse, energy is not a relativi... | [
"In addition to reasons already given by others, I also want to point out that the law of conservation of energy is not as rock solid as you might think. ",
"To understand why this is the case, we need to examine ",
"Noether's Theorem",
".",
"Noether's Theorem tells us that every differentiable symmetry of... | [
"We don't know. Maybe it's always been here. Maybe it can be created via a process we cannot fathom. Maybe the immutability of the amount of mass-energy in the universe only came to be after some initial creation event. Maybe the answer is beyond our intellect's ability to understand."
] |
[
"How often/likely is it estimated that people get cancer of some kind and their body defeats it, without them ever even knowing they had cancer in the first place?"
] | [
false
] | null | [
"I don't know a specific number, but based on probability alone I'd say many times a day. The cytotoxic T-cells of the adaptive immune system and the natural killer (that name is ",
") cells of the innate immune system are the body's own defence against cells that are infected, mutated or otherwise impaired or a ... | [
"If a mole is itchy, you should probably go see your GP and/or a dermatologist. It's one of the warning signs that it might be turning into something more serious. The others are irregular borders, uneven colour, size of more than 5mm, asymmetry and any recent changes, i.e. if it looks different from last month.",
... | [
"If a mole is itchy, you should probably go see your GP and/or a dermatologist. It's one of the warning signs that it might be turning into something more serious. The others are irregular borders, uneven colour, size of more than 5mm, asymmetry and any recent changes, i.e. if it looks different from last month.",
... |
[
"Since oil is causing so much trouble, and the US is a net exporter of natural gas, Why aren't there more vehicles powered by natural gas on the road?"
] | [
false
] | null | [
"One gasoline gallon equivalent (GGE) of compressed natural gas will occupy ",
"0.77 cubic feet of space at 2400 PSI",
".",
"One cubic foot of gasoline = ",
"7.5 gallons",
".",
"So, gasoline is a more compact means of storing energy making it a preferred fuel in cars. "
] | [
"Not to mention safer. Gasoline is surprisingly safe in a liquid form, at least compared to natural gas under pressure. ",
"And that's without considering the weight and danger of having to compress your natural gas for on-car storage. "
] | [
"All of the above is absolutely 100% true. It is also not the reason why we use gasoline instead of natural gas. If energy density were the sole concern then Diesel fuel or liquefied natural gas (both of which have a higher energy density than gasoline) would be our primary fuel source. However, as is the case w... |
[
"Speed Wobble, what is it?"
] | [
false
] | Could someone break down what is actually occurring when the phenomenon mentioned above begins? What causes it? Is it different for skateboards (2 wheels) vs a motorcycle? I've been a victim of this dastardly thing when I was younger and received quite a few scrapes, but I don't really understand it. Thanks in advance ... | [
"Speed wobble is a resonant condition that can't be easily predicted. This sort of resonant interaction can be either self damping, or divergent depending on the system involved. ",
"The trouble is, it's different for EVERY system. ",
"As for \"what's really happening\" I think I can describe it. We're goin... | [
"As a skateboarder, this is my response:\nOn your skateboard you have two trucks. Each truck has a base, which is screwed into the board, and the hanger, which the wheels go on. The soft rubbery bits on either side of the hanger are called bushings. What bushings do is enable the truck to return to a neutral positi... | [
"That makes sense, I was like 7 and was sitting on my board (a really crappy one) and went straight down a pretty big hill. Your point also brings to light a long-boarder video I just saw, he had the beginnings of a wobble until he hit curves, thank you for clearing that up. "
] |
[
"If I took an air horn into a vacuum, and depressed the button would there be a sound?"
] | [
false
] | null | [
"Would something happen? Definitely. Air horns function by releasing a pressurized air though a relatively narrow space. However, as there is no atmosphere for this outgoing air to go into, I expect that two things would happen.",
"Gas molecules in a vacuum won't diffuse, but rather fly ballistically. (Though wit... | [
"will really only travel \"forward\" out of the horn",
"Well there would be a pretty big spread of gas molecules. It's not a laser. Just clarifying."
] | [
"Thanks dude, but can you explain it like I'm five."
] |
[
"Why is the Earths mantle divided in two? And what is inside the mantle?"
] | [
false
] | I’ve read that the mantle inside earth is divided in two and I’ve also not really been able to find out if it’s liquid or something more hard. | [
"Are you referring to the upper and lower mantle? The difference is mineralogical. The upper mantle contains olivine, pyroxene, and +/- garnet, spinel. The lower mantle contains denser phases- bridgemanite, ferropericlase, Ca-perovskite. The lower and upper mantle are roughly the same composition, but the tremendou... | [
"The Earth's mantle is complex in structure. Very little is liquid, most of it is solid rock (though under significant pressure and heat, so it flows like hot plastic or gum). Melting requires specific conditions (typically decompression near mid-ocean ridge spreading or hydration melting near subduction zones... p... | [
"Well I’ve just been informed that it’s different minerals contained in the upper and lower mantle. So that would mean that it’s mostly solid with some areas being more liquidity like gum right?"
] |
[
"Why is fiberglass safe vs asbestos?"
] | [
false
] | They're both made of tiny fibers. What is the difference between them? | [
"First of all, the premise of the question is wrong: fiberglass is not safe, especially if it is made out of exceedingly thin fibers. Inhalation of fine fiberglass dust will probably lead to silicosis and other unpleasant health effects.",
"The difference in harmfulness between fiberglass and asbestos is due to t... | [
"Fiber glass is not safe. A mask and gloves are recommended when handling, and cutting materials with fiberglass in it produces lots of dangerous particles. ",
"Asbestos is most dangerous when it is ",
"friable",
", or easily crumbled by hand, releasing lots of particles. It also causes cancer somehow. Fiberg... | [
"The jury is still out but the idea is that fiberglass particles are small enough to get in your lungs and cause lacerations but asbestos particles may be small enough to lacerate individual cells and lead to cancer. "
] |
[
"Do prescription pills/medications really expire on the date said on the bottle?"
] | [
false
] | Or is it just a scam to keep pharmaceutical companies turning more profits from people throwing medicines away on the expiration date? | [
"Also: toxic metabolites may form in certain medications that can/will be toxic."
] | [
"It is definitely not a scam, over time the chemicals that make up the pill/medicine will degrade. How long it takes the medication to degrade will entirely depend on what medication it is, as some compounds will be more stable than others. ",
"Of course this isn't a black and white issue, it's not as if the day ... | [
"This depends heavily on the drug. The expiration period is determined by measuring various attributes of the drug over time. Once they are outside of certain limits, the drug is deemed unsafe or ineffective and it thus \"expires\". ",
"Keep in mind that the medication you are taking is chemical that is interacti... |
[
"Is there a geometric shape whose circumference grows as fast as its volume?"
] | [
false
] | null | [
"I don't understand what you mean. Grows with respect to what? Also, since circumference and volume have different units, their rates of change also have different units. So those rates are not directly comparable."
] | [
"I know that the circumference of a circle grows slower than the volume, when the radius is increasing.\nSo I asked myself, how the geometric shape would look like, where the circumference grows as fast as the volume."
] | [
"See my response below."
] |
[
"Is it possible to remember being born?"
] | [
false
] | [deleted] | [
"No. \nEpisodic memory starts around 2 years after your birth. Mostly due to the fact that you brain undergoes lots of change that, basically continously reformating, before settling.\nPoor wording, feel free to correct me."
] | [
"This question is currently impossible to answer, as we do not have any way of directly analyzing the mental experiences of animals. There has been a lot of interesting research in the last 15 years or so on whether animals have episodic memory, largely focused on whether animals can recall what, where, and when an... | [
"If it starts \"around\" two years, is it possible that some people have anomalous development, that are outliers in the dataset if you will, that do retain even small amounts of memory from before that time, just as I imagine there are those that develop significantly later because of some condition or another?"
] |
[
"Did Felix Baumgartner break the sound barrier and experience a sonic boom?"
] | [
false
] | The press conference said preliminary results indicate he was travelling at Mach 1.24. Obviously, this is faster than the speed of sound, but was there a noticeable sonic boom? Would he know he was travelling faster than sound? I understand that at such high altitudes the pressure it much less, but what effect would th... | [
"The Mach number is almost always reported relative to ambient conditions (I say ",
" always because sometimes you hear about the Shuttle orbiting at about Mach 25, and there isn't a defined speed of sound up there). This means that Baumgartner was travelling above the local speed of sound. This is really the onl... | [
"The speed of sound is actually slower at higher altitudes than it is at sea level. Wikipedia shows it doesn't decrease monotonically as you go up, though. ",
"http://en.wikipedia.org/wiki/Speed_of_sound#Altitude_variation_and_implications_for_atmospheric_acoustics",
"At higher altitudes the density of air is l... | [
"To piggy back on this, Mach 1 is ~761 at sea level and 59 degrees F. Are they calculating Mach 1 for his specific position and wouldn't that require a higher velocity due to to much thinner air? I don't recall the live readout getting over ~740 MPH during the free fall."
] |
[
"What is the medical consensus of vaccinating while presenting COVID-19 or similar viral symptoms?"
] | [
false
] | I couldn't find any factual information about that specific instance. Is that being contraindicated in some way? Is it relevant at all? Are there any potential hazards in doing so? | [
"Also, you would put others at the vaccine clinic—both staff and other patients—at risk by coming in while symptomatic."
] | [
"You should not get the vaccine if you are currently infected with Covid-19 or any other current infection. ",
"Depending on the country your in, it's at least ",
"strongly advised",
" to wait until you are fully recovered or you won't even be able to get the vaccination. In Germany for instance, you have to ... | [
"Thanks a lot to you and the community for this vital information. Very much appreciated."
] |
[
"How do your eyes prevent shaking while you're walking?"
] | [
false
] | I've paid close attention to how some camera's now use OIS, or optical image stabilization, and EIS, or Electronic image stabilization and I was wondering why my vision isn't shaking while I'm walking. Is it some physical thing near my eyes stabilizing what I see or is that handled by the brain? | [
"It is a little of both. ",
"The eyes are able to keep focused on a single point in space despite movement of the head thanks to something called the ",
"vestibular-ocular reflex",
" (VOR). Basically the movement-sensitive parts of the inner ear connect to the eye muscles through a rapid pathway that rotate... | [
"I've always been fascinated by this. I've read that it is the fastest reflex in the human body. ",
"To get an idea of just how impressive it can be, stand in front of a mirror and look yourself in the eyes. Now move your body, rotate your head, move in any way you can think of but keep looking into your own eyes... | [
"There are animals that cannot move their eyes, so of course they lack the reflex, and some vertebrates have vestigial eyes and so may lack the reflex. However, it seems to be shared by even the most ",
"primitive vertebrates",
". If any vertebrates lack it, that is because they lost if later on for whatever r... |
[
"Is there a particular reason why there are few islands in the Arctic Ocean?"
] | [
false
] | I was surprised that the most northerly island was just off the coast of Greenland. This seems quite a large area to have no islands at all, especially given that the Arctic Ocean is the shallowest ocean. Is it related to plate tectonics? | [
"The short answer is that it has to do with the way plate tectonics force continental basalt, which is the stuff that forms terrestrial topography like islands and continents, away from divergent boundaries in the ocean floor. Look at ",
"this diagram of global continental geology",
", and imagine a soup slowly... | [
"Well yes, the reasons are unknown. Pressure differential is one theory."
] | [
"100% with you until that last paragraph. It’s perhaps influenced slightly by the much shorter length of spreading ridges overall in the Pacific, but at the heart of it is the upwelling of various mantle plumes underneath the Pacific basin. For reasons unknown, the Pacific basin has seen more of this kind of action... |
[
"What would happen to Jupiter if it moved gradually closer to the sun? Could it survive at a distance as close as Mercury?"
] | [
false
] | null | [
"Hi Urisk, ",
"What would happen to Jupiter if it moved gradually closer to the sun? ",
"It would completely disrupt the inner solar system. The planets Mercury to Mars and the objects of the asteroid belt would be ejected from the solar system, shot into the sun or flung into highly eccentrical orbits at a min... | [
"Would certain gases burn off changing the actual planet?",
"No, not really. Jupiter atmosphere is almost completely made of hydrogen and helium, with trace amounts of other gases and elements. Due to the lack of strong oxidizers nothing will actually burn as it comes closer to the sun, but of vourse will heat up... | [
"there is a theory known as \"grand tack\" which holds that in the first 10-15 million years of the solar system, jupiter roamed around the inner orbits and gobbled a previous generation of planets. hope it stays where it is, at least for the rest of my life. "
] |
[
"Car engines: Why aren't there 2.0L V4 or 6.0L straight-12?"
] | [
false
] | null | [
"Because a 6.0L straight-12 would be gigantic, and there are some V4 motorcycles, but they are not 2.0L.",
"There are not 2.0L V4 car engines because, in general, 2.0L in line-4 engines get more power. V4s are more compact, but a car has to be so big in order to even work; you don't need that compactness. This is... | [
"I'm batgirl!"
] | [
"Stem cell research by day, muscle car mechanic by night! (I couldn't resist)"
] |
[
"Does it matter which side of aluminium(aluminum) foil is facing food while cooking for better heating?"
] | [
false
] | I remember a science teacher once telling me that the dull side out will help keep more heat directed towards the food. But then I was looking at wikipedia and it states that it doesn't make enough of a difference with reflectivity being 88% for shiny side and 80% for dull side. It sited the Reynold's website for thi... | [
"A lot of heat gets to your food via conduction and convection, rather than radiant transfer. So, some amount of radiant heat is reflected by the foil, but the air inside the oven and the pan the roast is sitting in will both transfer heat to the inside of the foil regardless."
] | [
"8% seems like a lot, but I suspect that figure is the difference in reflectivity of visible light.. if the material was isoreflective across the whole spectrum and radiative heat transfer was the only mechanism for heating then yes this might be a problem. However, tinfoil probably absorbs and reflects different w... | [
"That's a good point. I didn't think it might mean only for visible light. I suppose by going with what you and i_invented_the_ipod say that because of the other types of heating going on it would only make a difference in the beginning until the temps had a chance to normalize throughout. I wish I had two roasti... |
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