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Monday, July 16, 2018

I heard that detergents, soaps, and surfactants have a polar end and a non-polar end, and are thus able to dissolve grease. But so do fatty acids; the carboxyl end (the acid part) is polar, and the long hydrocarbon tail is non-polar. So why don't fatty acids behave like soap? What's the difference?

I heard that detergents, soaps, and surfactants have a polar end and a non-polar end, and are thus able to dissolve grease. But so do fatty acids; the carboxyl end (the acid part) is polar, and the long hydrocarbon tail is non-polar. So why don't fatty acids behave like soap? What's the difference?


I heard that detergents, soaps, and surfactants have a polar end and a non-polar end, and are thus able to dissolve grease. But so do fatty acids; the carboxyl end (the acid part) is polar, and the long hydrocarbon tail is non-polar. So why don't fatty acids behave like soap? What's the difference?

Posted: 15 Jul 2018 02:30 PM PDT

Bonus question: what is the difference between a surfactant and a soap and a detergent?

submitted by /u/Berkamin
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What is the "lowest" life form that performs a stretching reflex?

Posted: 15 Jul 2018 02:33 PM PDT

As I'm scrolling through r/aww and such, I see pics of small animals stretching their limbs in a kind of reflex fashion. Just wondering if anyone knows the earliest (or I guess "lowest") life form this has been observed in.

Edit: to clarify what I mean by "lowest," I guess I mean that out of all the evolutionary branches that exhibit this behavior (or a behavior that approximates it), the earliest branch that does not include humans that has extant species.

Edit 2: Bonus if anyone can answer the same question for yawning.

submitted by /u/sotaskimmer
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Why does blue seem to be the hardest color to achieve for so many things, such as LEDs, fireworks, and paints or dyes?

Posted: 15 Jul 2018 03:03 PM PDT

What makes blue special? Also what category would this be?

submitted by /u/PikpikTurnip
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Why did the Space Shuttle have a roll maneuver, as opposed to just launching in the right orientation?

Posted: 15 Jul 2018 01:53 PM PDT

It's funny, I didn't even think about it until I started making shuttles in Kerbal Space Program. Launching as the real Shuttle did gives me stability issues in the game while performing the roll, so I launch with the shuttle already facing the right way.

Was there a reason the Shuttle didn't launch facing east to begin with?

submitted by /u/supermegahypernova
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Why don’t physicists use relativistic mass anymore?

Posted: 15 Jul 2018 11:37 AM PDT

Do adult animals recognize their own siblings when they encounter each other in the wild?

Posted: 15 Jul 2018 11:13 AM PDT

What makes you wake up?

Posted: 15 Jul 2018 08:51 PM PDT

So what makes people wake up naturally? Is it our internal clock or is it just our bodies saying we've had enough rest? I ask this because I've found that sometimes if I go to bed late then I'll wake up earlier than if I went to bed early.

submitted by /u/acidSK8R89
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How much copper can D-penicillamine (DPA) chelate?

Posted: 16 Jul 2018 06:03 AM PDT

Hi, I have 0 background knowledge in chemistry and this is not for a homework. It's actually for better understanding of Wilson's disease.

I've read in "Chelation Therapy in the Treatment of Metal Intoxication (2016)" that in vitro 1000mg of D-penicillamine (DPA) chelates about 200mg of copper but in actuality only 1% (10mg) is secreted out of the body. How did the authors come up with this number and are there more empirical results on the drug's effectiveness as a chelator?

Another question is how do scientists and doctors measure how long before each meal should DPA be taken?

Thanks.

submitted by /u/superTUX380
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Does air have its own form of “surface tension” the same way water does?

Posted: 16 Jul 2018 12:38 AM PDT

My assumption is that the atoms are too far apart to create any form of tension compared to water. But would this be the case in a pressurized environment?

submitted by /u/7yearoldkiller
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How can scientists tell that there is very little antimatter in the universe?

Posted: 16 Jul 2018 12:19 AM PDT

Based on the Wikipedia level reading I've done it appears that in all respects antimatter should behave exactly as "regular" matter. So then how can we be sure that there aren't galaxies, stars, etc made of antimatter? What led scientists to the conclusion that all of the universe is made out of regular matter?

I'm not suggesting that there isn't an imbalance or that antimatter galaxies exist. I'm only asking how scientists, who know more than me, came to the conclusion that the universe is almost entirely regular matter when it should be observationally identical.

submitted by /u/RSTLNE3MCAAV
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Would you travel a further relative distance on the larger of concentric spheres or the same?

Posted: 16 Jul 2018 03:01 AM PDT

I was recently thinking about space flight/air travel etc and i couldnt logically come to a conclusion of this:

Imagine a sphere with centre point (equidistant to all other points on the sphere in 3axis)

Now another larger sphere encompassing the smaller sphere but with the same centre point in space.

You are standing at a point (x) on the larger sphere with a line bisecting the centre point (c) and outer surface of the smaller sphere (y).

You travel a distance (d) from (x) on the surface of the outer sphere to point (x1) with the same line bisecting the centre point of both spheres concentrically and where you stop at (x1) the line now bisects the smaller sphere's surface at (y1) and the distance between (y) and (y1) is now (d1).

Does (d) = (d1)? And what does this mean in terms of relativity for example does a person walking on the surface of a planet walk the same or more distance as a satellite traveling the same speed in the same amount of time in orbit?

submitted by /u/deeztoasticles
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Do interests/hobbies developed due to the environment or predisposition genetics?

Posted: 16 Jul 2018 04:45 AM PDT

Does the optical fiber reflect all types of light?

Posted: 16 Jul 2018 04:27 AM PDT

I just finished watching a video demonstration showing a fiber optic cable struck by two types of lasers, one green and one red. The cable transmitted the green light beam without problems, while the red one could not cross it. How does this happen?

submitted by /u/BlitzYTech
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How do Galaxies Accelerate?

Posted: 16 Jul 2018 12:48 AM PDT

I apologize if this is not flaired properly.

I was having a discussion with someone about the speeds that galaxies accelerate at. He was saying that in order to calculate the velocity of a galaxy, it would be as easy as using distance over time.

I fervently disagreed. I said that at the order of magnitude of a galaxy, moving from Point A to Point B is not that simple. Time will be affected by the gravitational field around the galaxy. Additionally, at this size, spacetime is moving itself. So deciding a point is not so simple.

Was what I said anywhere close to the truth?

submitted by /u/ChiefWamsutta
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I know the difference between venomous and poisonous, but does this distinction only apply to animals? Are there venomous plants?

Posted: 15 Jul 2018 04:49 PM PDT

I know there's a lot of plants that can sting you if you touch them like stinging nettle, but are they considered venomous?

submitted by /u/Kiloueka
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How do analog devices effectively use such high frequencies, but silicon devices are limited to the low GHz range?

Posted: 15 Jul 2018 03:42 PM PDT

I understand that a complex silicon device like a CPU is frequency limited by a number of factors such as signal propagation delay, but silicon transistors do have a fundamental switching frequency limit (ex. FinFET transistors seem to be workable up to ~30GHz from a quick Google search). But radio frequency equipment (even really old stuff) can go into hundreds of GHz and even into THz frequencies when looking at things like radio transmission/reception and astronomy research.

If you are transmitting and/or receiving signals on carriers that are hundreds of times faster than the fastest silicon transistors can switch, how are we able to make use of these parts of the spectrum?

Light is just extremely high frequency EM radiation, and fiber optics make use of only a tiny sliver of the available bandwidth of visible light (as far as I understand it). Is that also the case with millimeter and sub-millimeter wave radio?

submitted by /u/skaven81
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Does a virus always inject itself into the same location within a chromosome?

Posted: 15 Jul 2018 10:01 PM PDT

I was reading about the HeLa cell lines, and the book mentioned that the reason that the cells were able to divide indefinitely is that the HPV-18 virus infected a segment of the 11th chromosome that was important in suppressing tumors. That made me wonder if that particular virus always inserted itself into that region of the 11th chromosome, or if it just inserted itself into the first region of DNA that it fit?

submitted by /u/chazwh
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What is the actual difference between scattering and absorption at the atomic level, if both are exciting molecules, albeit at different magnitude?

Posted: 15 Jul 2018 07:54 AM PDT

I understand absorption and scattering is what gives things color, like why Chlorophyll is green (because it absorbs more in the red/blue levels), and water is bluish (since it absorbs more in the red region).

BUT I don't understand why this difference occurs; Why is resonant frequencies absorbed by molecules, if all it's doing is vibrating the molecules more than other wavelength of light. For example, if red light is more closer to the resonant OH bond stretching vibrations, it get absorbed, but blue light is not, so it gets scattered. Don't both wavelengths wiggle the molecules, therefore transmitting energy to the molecule, albeit at different magnitudes? What makes water molecules "give back" the blue light, but "keep" the red light ?

submitted by /u/wannastro
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Why can flies easily enter a trap but struggle to get out?

Posted: 15 Jul 2018 07:34 PM PDT

I saw a friend of mine post a fly trap and was wondering why the flies can get into the trap so easily, but struggle to get out? There were dozens in there dead and a dozen more alive and trapped -- unable to get out.

Also what makes them fly into the liquid? Do they eventually get tired and fall in? Thanks

submitted by /u/Kingkwon83
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How do spacecraft navigate in space even though there's no fixed point about which a co-ordinate system can be made, and there's no concept of direction in space like north-south or up-down?

Posted: 15 Jul 2018 11:18 AM PDT

What causes the initial signal from our brains to be fired when we decide to move a limb?

Posted: 15 Jul 2018 05:55 AM PDT

When I want to move my hand, I just think about it and it works. I decide to move my hand and a signal is sent from my brain which causes my muscles to expand/contract which makes my hand move. What creates this signal in my brain?

submitted by /u/facial_issues
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What manipulates the taste and texture of different types of meats?

Posted: 15 Jul 2018 05:01 PM PDT

Sunday, July 15, 2018

How do engineers plan for thermal expansion when laying traintracks in deserts where the daytime and nighttime temperatures are vastly different?

How do engineers plan for thermal expansion when laying traintracks in deserts where the daytime and nighttime temperatures are vastly different?


How do engineers plan for thermal expansion when laying traintracks in deserts where the daytime and nighttime temperatures are vastly different?

Posted: 14 Jul 2018 04:20 PM PDT

Do the lattice constants of NaCl and KCl change when water is added, if so do these changes remain when the water is removed or do the lattice constants return to their original lengths?

Posted: 15 Jul 2018 06:29 AM PDT

Does the water-temperature affect the effectiveness of how a water-surfactant solution binds to hydrophobic material?

Posted: 15 Jul 2018 04:30 AM PDT

Title.

All answers appreciated!

submitted by /u/Painaple
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Why do computer monitors change colors when the VGA cable is loose?

Posted: 15 Jul 2018 04:01 AM PDT

I've noticed when the VGA cable is about to fall out the monitors starts displaying everything pink or yellow or shows lines. Why?

submitted by /u/MexicanZorro
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What's this "Steering Ratio" on Tanks?

Posted: 15 Jul 2018 06:54 AM PDT

No, not a steering ratio on cars, only on tanks with tracks.

The thing about Steering Ratio on tanks is that there's a narrow range of ratio of the distance between the two side of the track, and the length the track that have a contact to the ground. Tanks that are too wide or too long will have a higher tendency to break their track than tanks that are following this ratio.

This guy talks about it at one point in his video (https://youtu.be/KfgifHh5R4Y?t=19m8s) and I would like to know what's the exact ratio for this "steering ratio" tank.

PS. If this is a wrong subreddit, please direct me to a correct one.

submitted by /u/Akyer_Besiege
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How do different objects in the field of view get "routed" to the area of the brain that can process them?

Posted: 14 Jul 2018 10:10 PM PDT

My understanding is that certain areas of the brain specialize in processing different types of objects, like faces. So if a person is looking at say two different faces and many other objects, how do the regions of visual input containing faces get sent to the appropriate area of the brain? Or does every brain region constantly scan the entire input for the thing it specializes in, like a convolutional neural network?

submitted by /u/PlentifulCoast
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How effective is carbon capture currently?

Posted: 15 Jul 2018 07:07 AM PDT

So, I'm a politics student and IIRC, I read that people and politicians aren't as green (ecologically) because they have faith that carbon capture will become effective enough to reverse or at least slow the effects of man-made climate change. So, are we close to an effective system that can achieve that?

submitted by /u/HenriGP
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Why do so many experiments studying the effects of a substance use rats?

Posted: 14 Jul 2018 09:05 PM PDT

For example:

X substance tested on rats showed the rats died/lived/experienced some sort of symptom.

Why are rats to popular in studies? Is there some sort of correlation in the way rats experience things that is similar to the way humans do?

submitted by /u/flamesfan99
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Do SSDs need to be overwritten for safe file deletion?

Posted: 14 Jul 2018 01:37 PM PDT

How do temporary autoimmune responses cause permanent damage?

Posted: 14 Jul 2018 04:13 PM PDT

Say, nerve damage, if specificity helps. If the immune system temporarily attacks myelin, why would the damage be permanent? Myelin doesn't heal quickly, but it does heal. And if the immune system can attack the non-regenerating axons, why? There would seem to be a lot of evolutionary pressure against that. (I mean, things don't get selected out overnight, but immune and nervous systems as we know them are both pretty damn old, aren't they?) Thanks!

submitted by /u/T2QTIW31hmtGbNsq
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If we don't know the limit of the observable universe how are we able to see the Cosmic Microwave Background and early glimpses of the universe?

Posted: 14 Jul 2018 07:47 PM PDT

Wouldn't neutrinos have near infinite mass according to Special Relativity rules?

Posted: 14 Jul 2018 10:42 PM PDT

So research shows that neutrinos have some small mass and they're traveling at speeds approaching the speed of light. The equation for mass dilation says the mass of an object equals m / sqrt(1 - v^2 / c^2), where m is its mass at rest. Therefore, since neutrinos have some mass and a speed close to or equal to c, wouldn't they have a huge mass?

submitted by /u/_golden_goat
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Does the Big Bang Theory, with everything starting from a point, violate Heisenberg's Uncertainty Principle?

Posted: 14 Jul 2018 08:19 PM PDT

How does one "shoot" alpha particles at something?

Posted: 14 Jul 2018 01:58 PM PDT

I was in chem the other day and we were talking about rutherford's famous experiment and how he shot alpha particles at gold foil. I know what alpha particles are but . . . how do you shoot them?

submitted by /u/s_buttars
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Can an Imago retain any memories of things that happened to it as a Larva?

Posted: 14 Jul 2018 04:10 PM PDT

Was originally thinking of Caterpillars and Moths when I wrote this, but in general, grubs/beetles, anything.

submitted by /u/Bcadren
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Neutrinos are fermions; technically they can't occupy the same space; so what happens?

Posted: 14 Jul 2018 09:50 AM PDT

Neutrinos are fermions; technically they can't occupy the same space, and thus could (however improbably) collide.

So what happens? What force / exchange particle modulates such a collision?

submitted by /u/recipriversexcluson
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If all different types of waves on the electromagnetic spectrum are just higher frequencies, why can't we make a 'box' to produce all of them?

Posted: 14 Jul 2018 03:32 PM PDT

I was reading through Feynman's Six Easy Pieces, and he talks about waving a piece of paper fast enough to produce different types of waves. I know that it's an illustration and not reality, but it got me wondering: Would it be possible to make a box with a dial on the front and a little oscillator inside that vibrates faster and faster to produce different waves depending on the selection?

submitted by /u/thepuppet33r
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Does the moon have volcanic eruptions?

Posted: 14 Jul 2018 03:29 PM PDT

Im currently watching a science channel show about the moon, then got thinking about plate tectonics. So does the moon have earthquakes and volcanic eruptions?

submitted by /u/lastlvllastlife
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What would happen to Sun-equivalent masses consisting purely of a single element, for various other elements?

Posted: 14 Jul 2018 11:46 AM PDT

Why can't fermions share quantum states, but bosons can?

Posted: 14 Jul 2018 11:50 AM PDT

So it's my understanding that fermions can't share quantum states and when the become close to doing so, they will interact and "collide". So what property about bosons, allows them to not collide? Also, does this extend to multiparticle bosons, such as mesons or alpha particles?

submitted by /u/sbcloatitr
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Saturday, July 14, 2018

Are there stars so hot they would appear black to the human eye?

Are there stars so hot they would appear black to the human eye?


Are there stars so hot they would appear black to the human eye?

Posted: 13 Jul 2018 01:36 PM PDT

Since stars are almost blackbodies, are there known stars so hot that their blackbody radiation completely falls into the UV wavelenghts so they emit no visible light at all?

And if there aren't, would they be theoretically possible?

submitted by /u/Authwarth
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Why does an atom need a neutron?

Posted: 13 Jul 2018 10:28 AM PDT

It has no energy, why?

submitted by /u/ClarkVv
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If rapidly cooling a metal increases its hardness, does the speed at which it's cooled always affect the end result (in terms of hardness)?

Posted: 14 Jul 2018 07:13 AM PDT

I was reading about how a vacuum furnace works and the wiki page talked about how the main purpose is to keep out oxygen to prevent oxidation.... one point talked about using argon in situations where the metal needs to be rapidly cooled for hardness.

It made me wonder: does cooling a melted metal faster than the "normal" rate give it a higher hardness? For example, if I melted steel in a vacuum furnace, and then flooded the space with extremely cold argon (still a gas, let's say -295 degrees F), would that change the properties of the metal as compared to doing the exact same thing but using argon at room temp?

submitted by /u/Elbynerual
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Would a person with higher blood pressure bleed out faster than a person with lower blood pressure?

Posted: 14 Jul 2018 03:13 AM PDT

Why is desert sand more fine compared to beach sand?

Posted: 13 Jul 2018 11:11 PM PDT

Does the rotation of the Earth effect the movement of plates?

Posted: 13 Jul 2018 10:36 PM PDT

Might be a stupid question, but recently I've been wondering about a scenario where the earth spins backwards. The Coriolis effect effects the air and ocean currents, but does it effect the mantle currents? If there was an alternate earth that spun in a different way from ours, would its continents look different at all?

submitted by /u/foggy__
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ISS Radiation shielding which perform better Polyethylene, Kevlar, Plastic or water?

Posted: 14 Jul 2018 06:12 AM PDT

Do pirhanas have pstrong redatory responses even without the presence of blood in their water?

Posted: 14 Jul 2018 06:05 AM PDT

I know, like sharks, pirhanas are really good at detecting the presence of blood in their water, and react very strongly to it, but let's say I want to cross a river which has pirhanas in it, will they attack me if I have no cuts/any « blood leak » anywhere on my body? I guess they will, but at what point? Also, sorry for any wrong phrases in the title, it sounds wrong but I couldn't word it better

submitted by /u/SmallerButton
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Is blue flame hotter than red/yellow flame?

Posted: 13 Jul 2018 09:10 PM PDT

I understand that blue light is higher energy than red light because it has higher frequency, E = hf. But in a wood fire, the flame is color red/yellow. But a gas lighter is bluish color near source and reddish/yellow near the end of flame. Does the color of flame depend only on Material in combustion? Or does actual color show which flame is hotter. For example, if you where shown three fires, one with red, one with yellow and one with blue flame, which one would you rather not touch? Sorry bad example, thanks in advance.

Edit: But isnt heat just infrared radiation? So color shouldnt matter?

submitted by /u/reznik99
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How do know so much about dinosaurs’ diets?

Posted: 13 Jul 2018 09:02 PM PDT

With a bunch of bones we have found out quite a bit. How do we know the things they ate?

submitted by /u/claudedeyarmond
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What exactly does diesel do when spilled on asphalt?

Posted: 13 Jul 2018 09:20 PM PDT

So I work at a marina and recently somebody spilled diesel in one of the storage warehouses. They didn't bother cleaning it up and it sat in puddles for about 24 hours. When it was finally noticed and mopped up, the asphalt underneath the puddles was soft. Now we have to shovel out the soft asphalt and dispose of it in a safe manner since I assume its soaked in diesel. My question is why did the diesel liquify the asphalt?

submitted by /u/Equinox9876
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How early does the brain start to flip images we see right side up?

Posted: 14 Jul 2018 04:17 AM PDT

Most diagrams of the eye, like this one, will show the image getting flipped after passing through the lens of your eye. This is rectified by the brain flipping what you see right side up when being processed. Do we know how early on in a persons life this process begins?

submitted by /u/Kherda0
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What's the difference between a panic attack and a nervous breakdown?

Posted: 14 Jul 2018 12:09 AM PDT

Was told to try posting this here, already got pretty sufficient answers from r/askreddit

submitted by /u/sewagedump
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What is the phase composition of water when heated isobarically through the triple point? (state function)

Posted: 13 Jul 2018 09:34 PM PDT

The triple point is the temperature and pressure at which solid, liquid, and vapor may exist in equilibrium with one another. However, at this pressure and temperature there are still infinite values of specific enthalpy for this 3-phase mixture, because it requires heat to melt/vaporize the components.

If we are heating ice at 611.2 Pa, then we can define the enthalpy of pure ice at 611.2 Pa and 273.16 K to be some value H. If we add heat until it is completely vapor, then the pressure will still be 611.2 Pa and the temperature will be 273.16 K, but the enthalpy will be some value H + ΔH.

At any given enthalpy between H and H + ΔH, there will be 3 phases in equilibrium - solid, liquid, and vapor. I'd like to figure out the composition (i.e. %solid, %liquid, %vapor) as a function of enthalpy between these two values and I'm very much struggling with this. Does anybody have insight into this?

I'm presuming that at first, ~100% of the added heat goes into melting the solid and as the amount of solid approaches zero, ~100% of the added heat goes into vaporizing the liquid. What happens in the middle is much more complicated. I made a graph of what I think it would look like, but this definitely isn't a state function by any means. If somebody could give me an equation or an article about this, I'd be super grateful. Thanks!

https://imgur.com/GYEM8vE

To add clarity, it would be equivalent to calculating composition as you move left-to-right on the triple point line of this plot:

https://imgur.com/NSDd7cB

submitted by /u/GahdDangitBobby
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Why is the H/H blood group more common in India compared to the rest of the world?

Posted: 13 Jul 2018 11:14 PM PDT

I read on wikipedia that the percentage of people with the Bombay blood type is 0.0004% and in India it is about 0.01%.

submitted by /u/shaktimaanlannister
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Chernobyl safetiness today. Are there any studies?

Posted: 14 Jul 2018 02:49 AM PDT

Hey guys,

I was wondering if there are any studies about safetiness of Chernobyl today.

submitted by /u/gamnog
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Will a piece of metal rust faster when water is running over it, or with water resting on it?

Posted: 13 Jul 2018 02:43 PM PDT

Assuming no edge effects where the water, metal, and air meet, would metal fully submerged in water rust faster in a water current or in stagnant water? Thanks!

submitted by /u/RupsterDupster
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Do humans have symbiotic gut amoebas?

Posted: 13 Jul 2018 09:19 PM PDT

We have a vast gut microbiome with beneficial gut bacteria, archaea, fungi and viruses. Are there any non parasitic amoebas in the gut and help us? Are there any other organisms that also live in our guts and help us like nematodes?

submitted by /u/Jaloss
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Can you layer sun protection products and is their SP factor cumulative?

Posted: 13 Jul 2018 11:15 PM PDT