Why do ice cubes crack when liquid is poured over them?

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• Why do ice cubes crack when liquid is poured over them?
• Is there anything special about the visible spectrum that would have caused organisms to evolve to see it?
• Why does (what role) HIV infected children have higher prevalence of staphylococcus aureus than for other staphylococcus species?
• Why does volcanic ash stay up for so long? Isn’t it relatively heavy?
• Why does the first ionization energy go down from Nitrogen to Oxygen?
• If the neutron does not possess any charge, how coud exists an antineutron?
• Why can't we create a perfectly straight beam of light with optics? What makes lasers so special?
• If a pregnant woman does not consume enough calcium during the babies development. Does her body choose to pull calcium from her own bones, or underdeveloped the bones of the child?
• Why are Copper(ii) compounds such as copper acetaf, bad for the Environment/people try to limit its exposure to the environment?
• What would a CIE 1931 chromaticity diagram look like if it's normalized based on MacAdam ellipse?
• Does our native language effect the tone/ pitch of our voice?
• When a chemical "binds to my receptors" what is actually happening?
• Why is the CMB cold spot more significant than other cold spots?
• Why are there moving shadows on the floor in front of my space heater?
• How is foreign DNA extracted from exhumed bodies?
• Is there any liquid more thin then water?
• In the 18th century, astronomers went around the globe to observe the transit of Venus knowing that if they compare their measurements, they could figure out how far the sun is. How does this work?
• Does operating temperature actually affect a electronic device's performance?
• Does Earth have Cryovolcanoes? If not, why?
• What did the early (Vostok) cosmonauts carry with them when they returned to Earth?

Why do ice cubes crack when liquid is poured over them? Posted: 12 May 2018 03:56 AM PDT submitted by /u/TMStage [link] [comments]

Is there anything special about the visible spectrum that would have caused organisms to evolve to see it? Posted: 12 May 2018 05:38 AM PDT I hope that makes sense. I'm wondering if there is a known or possible reason that visible light is...well, visible to organisms and not other parts of the electromagnetic spectrum, or if the first organisms to evolve sight just happened to see in the visible wavelengths and it just perpetuated. Not sure if this belonged in biology or physics but I guessed biology edit: I guessed wrong, it's more of a physics thing according to answers so far so I changed the flair for those who come after submitted by /u/thestray [link] [comments]

Why does (what role) HIV infected children have higher prevalence of staphylococcus aureus than for other staphylococcus species? Posted: 12 May 2018 05:39 AM PDT Almost all studies on prevalence of staphylococcus among HIV children indicate higher prevalence for staphylococcus aureus than for other staphylococcus species. Why is this the case? What role does HIV infection play to contribute to this? submitted by /u/opkyei [link] [comments]

Why does volcanic ash stay up for so long? Isn’t it relatively heavy? Posted: 12 May 2018 02:19 AM PDT submitted by /u/bronxlad [link] [comments]

Why does the first ionization energy go down from Nitrogen to Oxygen? Posted: 12 May 2018 03:47 AM PDT submitted by /u/mr_moo6 [link] [comments]

If the neutron does not possess any charge, how coud exists an antineutron? Posted: 12 May 2018 03:20 AM PDT I'm not physicist, but the intuitive concept of antimater that I have is that an antiparticle is just the same as the particle but with the oposite charge. Then, how can an antineutron exists and be detected? submitted by /u/felmoltor [link] [comments]

Why can't we create a perfectly straight beam of light with optics? What makes lasers so special? Posted: 12 May 2018 06:41 AM PDT Just looking at the inside of camera lenses, it seems we know optics well enough to control light with a pretty high degree of precision. So, why is it that I've never seen light focused into a perfectly straight beam via glass lenses or mirrors before, and instead lasers beams have to be generated through special laser sources? It seems like with our understanding of optics, it should be decently trivial to focus light onto a tiny spot then use a lense at that spot to straighten the beam out. Is there some inherent property with regular light that stops this from happening? Edit: just to clarify, I understand that the waves on a laser beam are temporally and spatially coherent. I'd just like to know why it is that a beam of light that isn't coherent seemingly can't hold a straight beam. submitted by /u/karlzhao314 [link] [comments]

If a pregnant woman does not consume enough calcium during the babies development. Does her body choose to pull calcium from her own bones, or underdeveloped the bones of the child? Posted: 11 May 2018 08:34 AM PDT Is there a sort of priority for all of the babies development? Is the mother's own body a priority, or the childs? Mostly curious about the bones. submitted by /u/PretendHumanoid [link] [comments]

Why are Copper(ii) compounds such as copper acetaf, bad for the Environment/people try to limit its exposure to the environment? Posted: 12 May 2018 12:39 AM PDT submitted by /u/--Kitsune-- [link] [comments]

What would a CIE 1931 chromaticity diagram look like if it's normalized based on MacAdam ellipse? Posted: 12 May 2018 03:39 AM PDT Here is a standard CIE 1931 chromaticity diagram with MacAdam ellipse: https://en.wikipedia.org/wiki/Color_difference#/media/File:CIExy1931_MacAdam.png You can see that the ellipses are not identical, with different shapes and sizes. That means the diagram is not isotropic on the basis of human perception. What if we modified the shape of the diagram, so that the MacAdam ellipses all become perfect circles with identical sizes. What would the diagram look like then? submitted by /u/mteechan [link] [comments]

Does our native language effect the tone/ pitch of our voice? Posted: 11 May 2018 09:29 AM PDT I feel like I've had this preconceived notion that people with different native languages tend to have different pitched voices than others, as a trend. Like native German speakers have a deeper voice than native Italian speakers. I'm not sure this is even true or not, but if it is, what causes it? Just the language itself and the way our mouth forms the different sounds needed to speak that language? submitted by /u/hung-like-a-horsefly [link] [comments]

When a chemical "binds to my receptors" what is actually happening? Posted: 11 May 2018 10:24 AM PDT I have a liquid on me which is an irritant. My arms feel like they are burning/on fire, and wiki says the compound binds to the receptors which are responsible for the regulation of skin temperature, hence i assume, making the skin hot like its on fire. A few hours later im fine, until I wash, then it gets re-activated, and i'm in the same pain as earlier. What is actually happening. Is the chemical compound sticking to cells and transforming them or something, and how does this even work? submitted by /u/electricp0ww0w [link] [comments]

Why is the CMB cold spot more significant than other cold spots? Posted: 11 May 2018 03:57 PM PDT Looking at images of the CMB, I can see many cold regions of the universe. Some of them even appear larger than the one we know as "the cold spot". Are the colors visually misleading of the numbers they represent? submitted by /u/nitemike [link] [comments]

Why are there moving shadows on the floor in front of my space heater? Posted: 11 May 2018 04:36 PM PDT Looking at the electric heater from above, there are moving shadows in front of it. The lighting comes from above. There is no smoke, so does the heat move, or bend, the light from above to concentrate it in some areas and remove it from others? Or, is it slowing the light down in some areas, something I'm pretty sure is impossible? submitted by /u/spudzilla [link] [comments]

How is foreign DNA extracted from exhumed bodies? Posted: 11 May 2018 07:19 PM PDT I just read a thread where the killer was found on DNA evidence after the victim's body was exhumed over 20 years later. How is foreign DNA, such as semen, able to survive within a rotting corpse for over 20 years and how is foreign DNA isolated and tested in that condition? submitted by /u/countessmeemee [link] [comments]

Is there any liquid more thin then water? Posted: 11 May 2018 12:00 PM PDT submitted by /u/trlhard [link] [comments]

In the 18th century, astronomers went around the globe to observe the transit of Venus knowing that if they compare their measurements, they could figure out how far the sun is. How does this work? Posted: 11 May 2018 08:21 AM PDT submitted by /u/DecentAnarch [link] [comments]

Does operating temperature actually affect a electronic device's performance? Posted: 11 May 2018 04:10 PM PDT Efficiency/reliability aside, does the temperature of a circuit make a meaningful impact? For example, would cooler processors work faster than hot ones? (Or vice versa?) Would this vary depending on the component? submitted by /u/guacamoleman141 [link] [comments]

Does Earth have Cryovolcanoes? If not, why? Posted: 11 May 2018 11:30 AM PDT Cryovolcanoes have been found on Enceladus, and there's evidence for them on many other moons like Titan and Triton. They're apparently pretty common in the solar system, and probably elsewhere. Does Earth have any cryovolcanoes? We have geysers, but I'm not sure if these are the same thing since they have a different geological mechanism, and we don't call Earth's geysers "cryovolcanoes". submitted by /u/StarlightDown [link] [comments]

What did the early (Vostok) cosmonauts carry with them when they returned to Earth? Posted: 11 May 2018 10:09 AM PDT There's all these online links with survival kits that cosmonauts carried after 1968 (the NAZ-3 survival kit), and the awesome TP-82 after 1982 for protection against wolves and bears in the wilderness, but what did the early Vostok cosmonauts (Gagarin, Titov etc) who landed without their capsule carry with them? In particular in terms of weapons, or any kind of survival kit for when they returned to Earth? Did they typically land very far away from their capsule? Did the cosmonauts just wait for help or go to find people? How did the rescue teams find them? And how long did it usually take rescue teams to find them? http://theappendix.net/posts/2013/11/the-cosmonauts-survival-kit submitted by /u/its_a_science [link] [comments]

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Moving water is one of the quickest ways to cool something down, but also to defrost it- why?

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• Moving water is one of the quickest ways to cool something down, but also to defrost it- why?
• Is the digestive process always first-in, first-out, or can quickly digestible meals "pass" slower digesting meals in the intestines?
• Why are moles often the site of skin cancer? Doesn't more melanin mean more protection from the sun?
• How significant is effect of friction losses in fluid transmission lines?
• How sure are that the K-T extinction event was caused by the Chicxulub asteroid?
• What are the effects of lithium levels (on the range of 0-50 mg/L) in drinking water?
• What causes gasses to be different colors?
• I have studied that that blood vessels, like any tissue, need nutrients and hence there are tiny blood vessels on their walls known as "vasa vasorum". The question here is, how these tiny structures get their own supply?
• What’s the consensus on using combination antibiotics in order to reduce the effect of bacterial resistance?
• Transplants, what's done before they happen?
• Is it possible to have an anaphylactic reaction upon your first exposure to the allergen?
• Are sound waves affected by gravity?
• Can scientist predict volcanic activity and why hasn't anything like Pompeii happened recently and how long after an eruption does a place recover?
• Is a shockwave different from a sound?
• How much "lag" is there in the human brain?
• Can birds get fat?
• How do we know, or do we know, that the parts of an atom are round?
• How does tidal heating work?
• Why don't strong magnetic fields disrupt the normal electrical activity of cells?
• How do radio stations know how many receivers are listening to them?
• Why is both helium 3 and deuterium required for a fusion reaction?

Moving water is one of the quickest ways to cool something down, but also to defrost it- why? Posted: 11 May 2018 04:58 AM PDT I remember learning a while ago that many rural and poor communities throughout the world use running water as refrigeration for food and that it's an incredibly fast way of cooling something. I recently discovered that running water is also practically the quickest way we have of defrosting things. I understand that water is a great insulator and heat conductor but that doesn't explain the counter-intuity here. Is there something else going on? submitted by /u/Dux0r [link] [comments]

Is the digestive process always first-in, first-out, or can quickly digestible meals "pass" slower digesting meals in the intestines? Posted: 10 May 2018 03:33 PM PDT Google searches only seem to bring up information on constipation. submitted by /u/mrfiveby3 [link] [comments]

Why are moles often the site of skin cancer? Doesn't more melanin mean more protection from the sun? Posted: 10 May 2018 06:47 PM PDT submitted by /u/AtomicFreeze [link] [comments]

How significant is effect of friction losses in fluid transmission lines? Posted: 11 May 2018 01:00 AM PDT In comparison to other losses in the system, e.g. consider a simple circuit of a pump and motor connected How would this change with line length? submitted by /u/mawst [link] [comments]

How sure are that the K-T extinction event was caused by the Chicxulub asteroid? Posted: 11 May 2018 06:50 AM PDT submitted by /u/dredawg1 [link] [comments]

What are the effects of lithium levels (on the range of 0-50 mg/L) in drinking water? Posted: 10 May 2018 05:58 PM PDT I was reading about lithium in well water and came across a few interesting articles: https://www.newscientist.com/article/2145074-lithium-in-tap-water-seems-to-both-raise-and-lower-dementia-risk/ Says low levels can raise or lower dementia risk, depending on dose https://www.tandfonline.com/doi/abs/10.1080/07315724.2002.10719188 Says low water lithium levels are correlated with some negative behaviors http://www.jpands.org/vol20no4/marshall.pdf Looks super sketchy, and pretty much says lithium is the best thing ever. Since I can't bring myself to trust that last one, I was hoping r/askscience might be able to give some input. submitted by /u/Hatsuwr [link] [comments]

What causes gasses to be different colors? Posted: 11 May 2018 07:22 AM PDT Like how oxygen and water vapor are colorless or how nitrogen is white right after it boils and then colorless once it settles. submitted by /u/riphitter [link] [comments]

I have studied that that blood vessels, like any tissue, need nutrients and hence there are tiny blood vessels on their walls known as "vasa vasorum". The question here is, how these tiny structures get their own supply? Posted: 11 May 2018 07:20 AM PDT submitted by /u/Mr_Nobel96 [link] [comments]

What’s the consensus on using combination antibiotics in order to reduce the effect of bacterial resistance? Posted: 11 May 2018 07:17 AM PDT I've read little bits from several different places on ways in which we can combat bacterial resistance. One study mentioned the use of several different antibiotics all targeting different essential pathways of a bacteria in order to reduce the chances that a certain amount of the population will survive and proliferate. It was something along the lines of: say the chance bacteria A has a mutation M1 which allows it to survive antibiotic 1 is 1/1000 and the chance it has mutation M2 to survive antibiotic 2 is also 1/1000. Then if we use both antibiotics 1 and 2 together the odds of any one bacteria having the exact two mutations necessary for survival decreases drastically as the probability becomes (1/1000)2. What if we use 3 antibiotics? Or 10? Are we already doing this? If so is it general practice? If we aren't why not? I read something which mentioned the interactions between antibiotics being a difficult factor to control for but surely we could work this out and we would work this out in order to fight something so threatening such as bacterial resistance? Thanks in advance :) submitted by /u/Fellainis_Elbows [link] [comments]

Transplants, what's done before they happen? Posted: 11 May 2018 06:54 AM PDT Like compatibility with donor and receiver. Why do some fail after some years? Are blood test done before such as mixing of the blood? submitted by /u/ocj213 [link] [comments]

Is it possible to have an anaphylactic reaction upon your first exposure to the allergen? Posted: 11 May 2018 05:49 AM PDT Second year medical student here - as I'm currently preparing for my immunology exam, I was reading up on anaphylactic response. As far as my textbook says, the 1st type of hypersensitivity reaction is the cause for anaphylaxis, but it says that such a reaction (anaphylaxis) can only occur in a later exposure - so I presume you can only get an allergic anaphylactic reaction upon your second exposure to the allergen. However, I was wondering - since common anaphylaxis triggers are venom from insect bites or stings, I was wondering, in a hypothetical situation - if I was bitten by a poisonous snake (e.g. by a common adder) - is it possible to get an anaphylactic response immediately or would I have to be bitten twice by the same species? Thank you! submitted by /u/TrustTheUniverse [link] [comments]

Are sound waves affected by gravity? Posted: 11 May 2018 04:47 AM PDT I was just reading a different post about volcanoes and someone had brought up a (I'm dumbing this down because phone) super loud eruption that was heard clearly 3000 miles away from its source. Following that statement was a fun fact of the sound waves circling earth four times. Is this possible? Wouldn't it go in a straight line either way and not stop until leaving the atmosphere? submitted by /u/MisterDomino15 [link] [comments]

Can scientist predict volcanic activity and why hasn't anything like Pompeii happened recently and how long after an eruption does a place recover? Posted: 10 May 2018 10:49 AM PDT So, after watching the news about the volcanic activity in Hawaii, I had a few different questions that are all related. 1.) Can scientists predict a volcano eruption, and if so how soon can they do it and how? 2.) Why has there not been any crazy volcanic activity like what you read about with Pompeii, etc.? 3.) How long does it take an area to recover/become habitable after a volcanic eruption? submitted by /u/theresalwaysthatone [link] [comments]

Is a shockwave different from a sound? Posted: 10 May 2018 08:33 PM PDT So I was holding a loaf of bread once as someone slammed the microwave door fairly hard on the other side of the kitchen. The sound wasn't too loud, but I could also sense something in the bread as the door slammed, like it was vibrating at that moment. So I assume that was the shockwave, somehow. I guess my question is, why can I only seem to feel this sensation when I'm holding literally nothing but a loaf of bread, when I can hear the sound just fine? If it's of any importance, the loaf is fairly 'sealed' from the outer layer, so it acts sort of like a balloon. submitted by /u/Reed1981 [link] [comments]

How much "lag" is there in the human brain? Posted: 10 May 2018 03:50 PM PDT It seems no matter where you go the brain is always compared to a computer. Since your neurons don't transmit at the speed of light in a vacuum there has to be some form of lag. I first thought well maybe it's reaction time but I'm more wondering about the time it takes for the senses to transmit and the brain to receive that information submitted by /u/TheRealSchackAttack [link] [comments]

Can birds get fat? Posted: 10 May 2018 02:36 PM PDT submitted by /u/octorabbit74 [link] [comments]

How do we know, or do we know, that the parts of an atom are round? Posted: 10 May 2018 09:52 PM PDT Every representation of parts of an atom, the protons, neutrons, and electrons, they're always presented as being round. Is this something we know or something that is at least likely, or is this just some rudimentary way of representing the parts, and if they are at least likely or we know they're round how do we come to this conclusion? submitted by /u/mysticclay [link] [comments]

How does tidal heating work? Posted: 10 May 2018 05:28 PM PDT I was watching a video and someone said that some Jupiter's moons aren't as cold due to a process called tidal heating but didn't add much to it. Can someone explain because it sounds cool? submitted by /u/kbX1 [link] [comments]

Why don't strong magnetic fields disrupt the normal electrical activity of cells? Posted: 10 May 2018 05:03 PM PDT If cells rely on charged particles for function, such as the electrochemical gradient of a nerve cell, it seems like a strong magnetic field should change the alignment/direction/movement of the molecules. submitted by /u/emergency_seal [link] [comments]

How do radio stations know how many receivers are listening to them? Posted: 10 May 2018 08:47 AM PDT submitted by /u/kiekrzanin [link] [comments]

Why is both helium 3 and deuterium required for a fusion reaction? Posted: 10 May 2018 11:33 AM PDT I was watching a video (https://youtu.be/mZsaaturR6E) (yep I'm not too versed) and they said that both deuterium and tritium or helium 3 was required for the fusion reaction. Why can deuterium not fuse with itself? If the plasma was hot/dense enough would this be possible? submitted by /u/MalgrugrousStudent [link] [comments]

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Is the human body affected by the changing seasons?

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• Is the human body affected by the changing seasons?
• What is the cost input/output of current nuclear fusion designs?
• Is there a certain priority list for a severely damaged human body to heal itself?
• If I lift an object up by 1m will its mass increase by a factor of ~g/c^2 from the extra potential energy? If so, is this effect experimentally observable or is gravity too weak?
• What makes two antidepressants in the same class different from one another?
• What are the differences between the mechanisms of bipolar depression and of unipolar depression?
• How have astronomers been able to make reliable estimations about the rotational velocity of galaxies given that an estimated full rotation takes over a billion years and radio telescopes observing them have been around for less then 100 years?
• Do herds of Caribou have a leader?
• What happens when a storm crosses the Grand Canyon?
• Are there any theories of a correlation between massive volcanic eruptions and a reversal of earth's magnetic field?
• What makes nuclear bombs so difficult to build?
• How do cells choreograph their growth to form the proper shape of the bone or organ?
• How do substrates actually get into their active sites in enzymes?
• Do we currently have any precautions installed in case an asteroid starts heading towards Earth? If so, what are they?
• Is there anything that can catalyze nuclear reactions?
• Why do vegetables such as asparagus/beets change the color of our pee, but artificial colors don't?
• Why is the relativistic adiabatic index 4/3?
• When supposing a product solution to solve a linear PDE, how do we rule out existence of solutions that cannot be expressed as a sum of product solutions?
• Where exactly does the energy in a nuclear reaction (fission and fusion) come from, since the number of particles remains unchanged?
• Is there one big, planetwide weather system, or does each country calculate their own? If so, what sort of communication exists between them?
• How does ethanol affect animal cells?

Is the human body affected by the changing seasons? Posted: 10 May 2018 06:23 AM PDT If we don't grow a winter coat like dogs, we don't have a set mating season, we don't migrate, etc, are we affected in any other way? If not, at what point did we lose those traits? submitted by /u/maudiestirling [link] [comments]

What is the cost input/output of current nuclear fusion designs? Posted: 10 May 2018 03:27 AM PDT Unsure whether to flair economics or physics for this, but I was curious as to the current gap in the cost of the energy input to the energy output worth of current nuclear fusion designs. submitted by /u/Lost_Sojourner [link] [comments]

Is there a certain priority list for a severely damaged human body to heal itself? Posted: 09 May 2018 07:04 AM PDT Does human body have a priority list for healing the body? For example: if a human body has multiple fractures, severed nerves, multiple lacerated organs, internal bleeding and cuts and bruises, how does the body react to the healing process? Which of the wounds and damaged areas it starts to heal first? I am aware of different kinds of shocks and reactions to the human body, but lets cast those aside. Is it strictly related to DNA only or is there some sort of other mechanisms the body/brain uses? submitted by /u/M3nt4lcom [link] [comments]

If I lift an object up by 1m will its mass increase by a factor of ~g/c^2 from the extra potential energy? If so, is this effect experimentally observable or is gravity too weak? Posted: 10 May 2018 05:29 AM PDT submitted by /u/grumblingduke [link] [comments]

What makes two antidepressants in the same class different from one another? Posted: 09 May 2018 08:42 PM PDT I know different classes target different serotonin receptors, but what is the difference between two SSRI's, or two SNRI's? Why does one SSRI work well for someone, but a different SSRI doesn't work at all for them, even though the two drugs are in the same class? And if someone responds well to an SSRI, does that make them more likely to respond well to every SSRI? submitted by /u/heyitsme_12345 [link] [comments]

What are the differences between the mechanisms of bipolar depression and of unipolar depression? Posted: 10 May 2018 03:26 AM PDT submitted by /u/chrishuang1206 [link] [comments]

How have astronomers been able to make reliable estimations about the rotational velocity of galaxies given that an estimated full rotation takes over a billion years and radio telescopes observing them have been around for less then 100 years? Posted: 10 May 2018 03:22 AM PDT I was reading some posts on here and on the web about dark matter and why astronomers believe it exists. My understanding is that two of the reasons are connected to observations concerning the rotational speed of galaxies. Firstly, the rotational velocity observed did not match the estimated mass of stars in an observed cluster, secondly that all stars in galaxies appear to rotate at a constant velocity. This I understand. What I don't understand is how can astronomers be so sure about the observed rotational velocities - if a full galaxy rotation takes over a billion years then all that we can have been able to observe since we built radio telescopes is 10 to the power -7 of that rotation (Sorry unable to write maths in word)? Which is a tiny, tiny fraction of a degree. How can they be so sure that there is no sizable error in there - how can they even see that tiny amount of rotation? Lastly, a less clear and perhaps less interesting question, connected to the above, how do they correct for our own Milky Way's galactic rotation when making observations? Presumably they must be able to tell which galaxies are rotating along the same axis as ourselves and which are tilted away from our axis and by how much? I'm running on a layman's assumption that there might be a galaxy rotating identically to the way we rotate in which case surely there'd be no observed rotation? But when they detect a rotation are they able to state with certainty how much the observation is affected by our relative rotation or is that open to error too? submitted by /u/OriginalGreasyDave [link] [comments]

Do herds of Caribou have a leader? Posted: 09 May 2018 06:54 PM PDT submitted by /u/69waystodie [link] [comments]

What happens when a storm crosses the Grand Canyon? Posted: 09 May 2018 05:38 PM PDT Curious about the title. submitted by /u/MundialMan [link] [comments]

Are there any theories of a correlation between massive volcanic eruptions and a reversal of earth's magnetic field? Posted: 09 May 2018 09:10 PM PDT I was reading this article about increased seismic activity in the Yellowstone basin. In the article it stated that the last major eruption of the Yellowstone super volcano was about 640,000 years ago, which was about the same time as the last magnetic pole reversal. Are both Earth's magnetic field and volcanic activity controlled by Earth's core? submitted by /u/fuckingoff [link] [comments]

What makes nuclear bombs so difficult to build? Posted: 09 May 2018 08:23 PM PDT I see in the news developing countries threaten to build a nuke. What are the barriers to making them and why do developing nations struggle with it? submitted by /u/transcendtime [link] [comments]

How do cells choreograph their growth to form the proper shape of the bone or organ? Posted: 09 May 2018 05:53 PM PDT As the title asks, how do cells know what the boundaries of their growth should be (non cancerous) and choreograph proper organ and bone formation? In other words, how do cells know which direction to grow in order to form the normal shape of that tissue? In my mind, there would have to be some separate process in charge of controlling the cells that is aware of the position of each cell and can control the growth speed and direction. But I feel that is probably wrong. I understand the concept of stem cells becoming specialized cells, with full instructions about what the cell should be and how it behaves. What i don't understand is the choreography involved in shaping. submitted by /u/KorgRue [link] [comments]

How do substrates actually get into their active sites in enzymes? Posted: 09 May 2018 08:57 PM PDT It seems that the chances of the substrates finding their way into the active site would be very uncommon due to their complex shapes, is there an aid or is it just through concentration of both elements? submitted by /u/MoistAmphetamine [link] [comments]

Do we currently have any precautions installed in case an asteroid starts heading towards Earth? If so, what are they? Posted: 09 May 2018 03:11 PM PDT submitted by /u/fusrohdab [link] [comments]

Is there anything that can catalyze nuclear reactions? Posted: 09 May 2018 05:52 PM PDT submitted by /u/FrostyFrisby456 [link] [comments]

Why do vegetables such as asparagus/beets change the color of our pee, but artificial colors don't? Posted: 09 May 2018 08:03 PM PDT submitted by /u/Calicomonster [link] [comments]

Why is the relativistic adiabatic index 4/3? Posted: 09 May 2018 05:30 PM PDT I was told that in the relativistic limit the adiabatic index approaches 4/3 for a monoatomic gas instead of 5/3 in the non-relativistic case. I was told this occurs due to a reduction in degree of freedom but this may be incomplete and does not quite explain the new expression since adiabatic index = (n + 2)/n where n is the # of degrees of freedom. Thus I am wondering both quantitatively and qualitatively, why does the adiabatic index decrease, and to 4/3 specifically, in the relativistic regime for a monoatomic gas? submitted by /u/CallMeDoc24 [link] [comments]

When supposing a product solution to solve a linear PDE, how do we rule out existence of solutions that cannot be expressed as a sum of product solutions? Posted: 09 May 2018 05:28 PM PDT In part I want to know how this was justified historically, if it was at all. This is for a presentation about fourier series and I want the logic to be as airtight as possible. I'm willing to weaken the assumptions to avoid having to say "... which we know for technical reasons too advanced to get into." in Fourier's book The Analytic Theory of Heat (1822), where he first develops fourier series, he uses the product solution trick to solve the heat equation. He does not explicitly address the question of whether there could be solutions that aren't a sum of products. He does prove uniqueness of his solutions, but only in a framework that presupposes his general form encompasses all possible solutions. Was Fourier being sloppy relative to modern standards of rigor, or is there some unstated result he's relying on? I'm aware that, in the language of functional analysis, it's not difficult to show a fourier series converges to its associated function if the latter is in the right space, and that this was shown contemporaneous to Fourier. What I'm looking for is, how do we (or how did Fourier) justify the conclusion we found the full solution of the linear PDE when we solved it by assuming the solution can be expressed as a sum of products of functions of one variable. submitted by /u/yassert [link] [comments]

Where exactly does the energy in a nuclear reaction (fission and fusion) come from, since the number of particles remains unchanged? Posted: 09 May 2018 03:01 PM PDT I know it has something to do with changes in the amount of energy holding atoms together, but I feel really fuzzy on that. submitted by /u/rebblt [link] [comments]

Is there one big, planetwide weather system, or does each country calculate their own? If so, what sort of communication exists between them? Posted: 09 May 2018 08:19 AM PDT submitted by /u/walt02cl [link] [comments]

How does ethanol affect animal cells? Posted: 09 May 2018 06:38 PM PDT Does it interact with receptors or does it pass throught the lipid bilayer? If the latter, What does it interact with inside of the cell? Thanks in advance submitted by /u/Big_catC [link] [comments]

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