- Newtons second law of gravity and coulomb's law for electricity are almost the same. Why can electricity attract and repel, while gravity can only attract? Are we confident gravity doesnt repel anywhere in the universe?
- This is a thought experiment, but assuming the absence of nuclear fusion, is it possible for a star to be formed entirely from hydrogen? Would the star survive?
- What is the molecular level description/justification of the Bernoulli Principle?
- Why can’t you consume alcohol while on antibiotics?
- How is Kosher salt different from regular non-iodized salt other than crystal size?
- Why does spicy food make your nose run?
- If you were watching Earth from 100 million light years (or any other number) away, would you see a "livestream" of what happened in the past?
- If you fell into a black hole, wouldn't you cook you due to severely blue-shifted light?
- Will the Hyperloop see sonic booms?
- Why does heating up a magnet remove its magnetic pull?
- If only around 2% of our DNA codes for proteins, what is the function of the other 98% of our DNA?
- Are circumference lengths always an irrational number?
- Where or how do medical professionals get adrenaline for usage?
- How did scientists first determine the molar masses of different substances?
- What's the deal with these colour scales used in full sky temperature maps?
- When looking at an LED display, I can get it to do a Mexican wave by humming. Different pitches of hum cause the oscillation to speed up or slow down in frequency. No one else I know has ever been able to do this and people think I am mad. Has anyone else noticed this, and why might it happen?
- What is the smallest neutron bomb possible, and what would be the efficacy of such a targeted blast radius?
- How do the hairs on my arms, chest and legs know how long they are and to stop growing?
- If there are millions of asteroids entering Earth's atmosphere every day, and there quite a few man-made satellites orbiting Earth including the International Space Station, how is it possible they are not destroyed?
- How do heat-shrinking plastics work?
- Why is that heavy snow sometimes doesnt stick to the ground and build up and other times it does?
- What would the ramifications have been had Tsar Bomba been an underground test?
| Posted: 19 Jan 2019 06:09 PM PST |
| Posted: 20 Jan 2019 02:01 AM PST |
| What is the molecular level description/justification of the Bernoulli Principle? Posted: 20 Jan 2019 05:23 AM PST The below shouldn't be necessary to answering the title question, but will help with understanding where I'm coming from and what I mean. Feel free to skip over it. At university, I studied Chemical Engineering i.e. a lot of fluid flow. My desire to understand things at fundamental levels didn't always go hand-in-hand with the teaching nor the typical engineering mindsets, so I was never fully satisfied with some of the descriptions of reality that were offered. The unsatisfying description in question here is the Bernoulli Principle. I don't have a fluid dynamics textbook to hand, so I'm gonna go with Wikipedia here for the principle's definition with regards to just fluid velocity and fluid pressure: "...an increase in the speed of a fluid occurs simultaneously with a decrease in pressure..." I'm not denying that this happens under certain conditions, but it seems this statement doesn't apply to all conditions. For example, a water truck's water (presumably) has the same pressure when travelling at constant velocity of 40mph vs 60mph (it feels very counter intuitive to imagine there being some truck speed where the water pressure would drop to the water's vapour pressure and cause it to boil). We know that the principle does apply in the case of pipe fluid flow, for example in a venturimeter. So, what's the fundamental difference here vs the water truck example? Why does that difference lead to the difference in pressure behaviour, despite both being instances of changes in fluid velocity? I'm not denying the veracity of the first law of thermodynamics when I say this, and I realise that the Bernoulli equation is essentially an energy balance, but I don't think "it's because of the energy conservation on/within the fluid" is actually an answer to what is fundamentally happening and doesn't address the difference. Rather, that statement serves as more of a heuristic that allows us to easily figure out the state of the system. But, the universe doesn't just adjust the pressure when the velocity increases so that the total energy change is zero, instead there are other processes at play, the net/emergent/observable result of which is that the total energy change is zero. This result is more convenient to work with in most instances, but doesn't necessarily allow you to work backwards to what actually took place "behind the scenes", which is what I'm wanting to do here. To understand why we observe the pressure dropping when the velocity increases in some cases and not in others, I think a Kinetic Theory style molecule level description of fluid pressure needs to be applied. If we could perfectly describe a fluid as a system of individual molecules that interact with one another according to their individual molecular properties and states, and simulate it according to Newton's laws of motion, I imagine you would see the Venturi effect/Bernoulli principle emerge in certain cases without even needing to explicitly program that behaviour into the simulation. So... What is the molecular explanation of the Bernoulli Principle? [link] [comments]  |
| Why can’t you consume alcohol while on antibiotics? Posted: 19 Jan 2019 07:42 PM PST |
| How is Kosher salt different from regular non-iodized salt other than crystal size? Posted: 19 Jan 2019 07:05 PM PST This is really more of a food science question but I feel chemistry is the right tag since a 'food science' flair doesn't exist. Are there other trace metals that lower the sodium content like Himalayan salt? Or am I missing the reason people pay more money for a larger, less refined crystal of the same chemical composition (it's not like they're diamonds) [link] [comments]  |
| Why does spicy food make your nose run? Posted: 19 Jan 2019 06:06 PM PST |
| Posted: 20 Jan 2019 07:09 AM PST Perhaps my question isn't entirely clear so let me explain my thought. If light takes 100 million years to travel to a distant location, the person watching Earth from that point (assuming they have some sort of super hi-tech telescope) would see what happened 100 million years ago. But it's not just one moment of light that travels the distance, but a sequence of light, a new picture with every second so to speak. So would a person from afar actually see what happened here 100 million years ago sort of like in a video? [link] [comments]  |
| If you fell into a black hole, wouldn't you cook you due to severely blue-shifted light? Posted: 20 Jan 2019 04:18 AM PST This is assuming, of course that you're falling into a black hole big enough that the tidal forces aren't ripping you apart as well. [link] [comments]  |
| Will the Hyperloop see sonic booms? Posted: 20 Jan 2019 02:47 AM PST Since the Hyperloop concept is to operate high speed trains in a near-vacuum tunnel, I was wondering if they can reach the speed of sound and if it can, will there be a sonic boom? [link] [comments]  |
| Why does heating up a magnet remove its magnetic pull? Posted: 19 Jan 2019 04:42 PM PST I just watched a video by The King of Random, in which he heated a powerful neodymium magnet to about 1800° and checked to see if it still attracted metal, which it did not. He also tried heating the metal instead of the magnet, with the same result. [link] [comments]  |
| If only around 2% of our DNA codes for proteins, what is the function of the other 98% of our DNA? Posted: 19 Jan 2019 07:42 PM PST |
| Are circumference lengths always an irrational number? Posted: 20 Jan 2019 04:33 AM PST If π is an irrational number, and thus cannot be represented as a fraction, and the circumference length c = 2πr, then π = c/2r, which is a fraction representation. Does this mean that a circumference length is always irrational as well? [link] [comments]  |
| Where or how do medical professionals get adrenaline for usage? Posted: 19 Jan 2019 05:27 PM PST |
| How did scientists first determine the molar masses of different substances? Posted: 19 Jan 2019 02:10 PM PST To elaborate a bit on my question: when for example it was first discovered that the molar mass of water was roughly 18.015g/mol, how did they know for sure that they at that time were weighing the exact amount of water molecules that go into 1 mole? Or in case they calculated it from a smaller sample of particles where they knew the exact amount of particles and what they weighed, how did they determine exactly how many particles were in the sample? More generally I guess I'm asking is, how do you determine the exact amount of particles of any substance that you have in a container at a given point? I hope I phrased this somewhat understandably and not too convoluted. I wasn't sure how to put it in different words. [link] [comments]  |
| What's the deal with these colour scales used in full sky temperature maps? Posted: 20 Jan 2019 01:11 AM PST Reading about the cosmic microwave background I stumbled upon these full sky temperature maps and the first thing that confused me is the scaling scheme. How to use the same colour (white) two times on the same colour scale? Source: https://arxiv.org/abs/1807.06205, page 4: "Fig. 1. Fluctuations of the sky emission in each of the nine Planck frequency bands, after removal of a common dipole component. The fluctuations are expressed as equivalent temperature variations at each of the seven lowest frequencies, so that fluctuations with a thermal spectrum will appear the same in each map (except for the effects of the varying resolution of the maps). The highest frequencies, which monitor the dust emission, are expressed in more conventional units." [link] [comments]  |
| Posted: 19 Jan 2019 08:53 AM PST Clarification- the oscillation is only visible in my eyes, I cannot physically effect the display itself! [link] [comments]  |
| Posted: 19 Jan 2019 10:58 AM PST |
| How do the hairs on my arms, chest and legs know how long they are and to stop growing? Posted: 19 Jan 2019 10:55 AM PST If i shave them off, they instantly start growing back, so they must have some idea of how long they are. What's going on? [link] [comments]  |
| Posted: 19 Jan 2019 09:53 PM PST I also wanted to add that since the Moon is peppered with craters, I would think that the chances of asteroids hitting anything we send into space is high, what is your thought? [link] [comments]  |
| How do heat-shrinking plastics work? Posted: 19 Jan 2019 06:03 PM PST If heat makes substances expand at a molecular level and cold makes substances contract, how do heat-shrinking plastics work? I know that water expands as it freezes into ice because of the organization of the molecules into a crystalline structure, but I'm sure it isn't the same mechanism in reverse. (Maybe I'm wrong?) TIA! [link] [comments]  |
| Why is that heavy snow sometimes doesnt stick to the ground and build up and other times it does? Posted: 19 Jan 2019 03:10 PM PST |
| What would the ramifications have been had Tsar Bomba been an underground test? Posted: 19 Jan 2019 11:23 AM PST So the Soviets designed the largest bomb possible (100 Mt), then cut it in half, then detonated the largest bomb ever detonated (50 Mt) in the atmosphere. What would have happened to the planet had the Soviets buried the bomb in the Earth's crust? Could it have penetrated all the way through the crust? What would life look like on the planet had they done this, whether with the 50 or the 100 megaton model? [link] [comments]  |
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