How strong is human skin relative to other animals? | AskScience Blog

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Tuesday, November 19, 2019

How strong is human skin relative to other animals?

How strong is human skin relative to other animals?


How strong is human skin relative to other animals?

Posted: 18 Nov 2019 06:19 PM PST

How do amoebas know not to fuse with other amoebas with the same genes?

Posted: 19 Nov 2019 04:26 AM PST

When they extend their pseodopods they sometimes engulf some stuff, which requires them to reattach two pseodopods around the stuff. So assuming an amoeba meets another of the same species, maybe even it's own sister, what mechanisms stops them from fusing into one cell?

submitted by /u/shinarit
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Why is the middle of the electromagnetic spectrum unable to penetrate solid materials?

Posted: 18 Nov 2019 06:43 PM PST

So at the lower frequency side you have Radio Waves, and those can easily penetrate materials, hence our cellphones work indoors.

At the higher frequency side, the ionizing radiation portion (so x-rays, gamma rays), the radiation is able to easily punch through materials again (for example needing say large amounts of lead to shield you from them).

But in the middle around visible light, infrared, and UV it is blocked by solid opaque objects.

Why is this?

submitted by /u/Izerpizer
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If the solubility of CO2 drops with increased temperature, why are the oceans then acidifying?

Posted: 19 Nov 2019 01:37 AM PST

The amount of CO2 that can be dissolved in water falls with increased temperature and the same holds true for other gases, but of course at different rates. When CO2 is dissolved some of it will be converted into the carbonic (IV) acid, thus lowering the pH of the ocean (I know it is slightly basic).

But since the temperature of the earth is increasing and especially that of the upper layers of oceans (who are most responsible for CO2 intake, I presume), how are the oceans acidifying? And why isn't CO2 released from water into the air?

Kind regards,

Lux

submitted by /u/LuxKop
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Do earthquakes affect the planet's orbit?

Posted: 18 Nov 2019 06:14 PM PST

Wouldn't Newton's third law suggest that no amount of planetary wriggling could cause it to move in space?

submitted by /u/ProtoZone
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Why is TUC (Time of Useful Consciousness) so short at altitude, compared with time one can hold one's breath at the sea level?

Posted: 18 Nov 2019 06:13 PM PST

I can hold my breath for 45 seconds, maybe one minute at sea level, and while I couldn't do any strenuous activity without shortening my apnea performance, during that minute I can remain conscious and (it seems to me) capable of good judgement, and of reacting to external stimuli competently.

However, for high altitude flight (decompression and exposure to external pressure), the FAA publishes a table of https://en.wikipedia.org/wiki/Time_of_useful_consciousness where the TUC at 37,000 feet is 30 seconds to 1 minute; half that much if there were a rapid decompression.

At higher altitudes, all the way out to space, the TUC is only a handful of seconds.

Why?

Intuitively, I completely understand that the loss of partial O2 pressure will make my breathing inefficient, but even assuming the worst case that I can't receive ANY new oxygen from the atmosphere, I should be able at least to match my apnea performance at sea level using the oxygen I already have in my bloodstream.

Since TUC is way shorter than that, I must assume that there is another factor at play, specifically that I must be effectively losing some of the oxygen that was already in my body.

What is the physiological mechanism that underlies that?

submitted by /u/cazzipropri
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[Particle Physics] Can a particle have internal energy stored as anything OTHER than mass?

Posted: 18 Nov 2019 04:35 PM PST

A question states that a particle splits in two pieces that go away from each other at high velocity. According to definitions and properties of particles in particle physics, is it necessary that the energy to accelerate those two pieces comes from mass (i.e. E = mc^2)? Or is it possible for there to be internal energy stored within the original particle in a form OTHER than mass?

This is not a homework question - I'm just wondering because, in my current course on modern physics, these problems always assume that the energy to accelerate the pieces comes from mass and nothing else.

submitted by /u/Aedificatus
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What are the rates of decay of intermolecular forces?

Posted: 18 Nov 2019 07:08 PM PST

https://chem.libretexts.org/Bookshelves/General_Chemistry/Map%3A_Chemistry_(Zumdahl_and_Decoste)/16%3A_Liquids_and_Solids/16.01%3A_Intermolecular_Forces

The website claims:

"the attractive energy between two ions is proportional to 1/r, where r is the distance between the ions"

"the energy of the interaction of two (permanent) dipoles is proportional to 1/r3"

"London was able to show with quantum mechanics that the attractive energy between molecules due to temporary dipole–induced dipole interactions falls off as 1/r6"

Are these statements true? If so, why don't these forces follow the inverse square law since they are electrostatic?

submitted by /u/lurker4011
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What is the ultimate source of nitrogen and nitrates in aquatic ecosystems?

Posted: 18 Nov 2019 10:17 AM PST

Nitrogen fixation obviously isn't an option underwater. I know that aquatic plants get nitrates from animal wastes and decomposing animals, but where did the nitrogen in their bodies originate, and at what point if any did it move from the atmosphere to the water?

submitted by /u/UnluckyDouble
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What determines the size of a sonic boom? Is it how loud the aircraft is, or its size?

Posted: 18 Nov 2019 11:13 AM PST

Are there any components of blood which are unique to blood?

Posted: 18 Nov 2019 07:30 AM PST

I'm a fantasy writer, and am trying to explain vampires. Aside from drinking blood purely for the reason of including a Virgin Maiden in the story, is there anything in blood which can't be obtained any other way that would warrant the drinking of it? It doesn't have to be anything that could realistically sustain a person, jut a unique substance or else extremely rare in the natural world. From looking at a list of what makes up blood, I am both floored at how much is in there an hopelessly lost, but so far I'm thinking some kind of hormone or insulin makes the most sense. I'd there's anything better, please let me know.

submitted by /u/the_god_of_none
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Why are there fewer polyatomic cations than anions?

Posted: 18 Nov 2019 10:44 AM PST

I was looking through the tables of polyatomic ions and I noticed that they usually only give ammonium and hydronium as examples of cations. Wikipedia gives some extra but obscure examples of polyatomic cations such as phosphonium and fluoronium. The list of polyatomic anions seems to be much more diverse. Why is that? Something to do with increasing electronegativity and valence electrons as we go across the periodic table?

submitted by /u/AzoMage
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Can ionized atoms/molecules ionize other atoms/molecules through contact?

Posted: 18 Nov 2019 10:07 AM PST

Can ionized atoms/molecules ionize other atoms/molecules through contact?

submitted by /u/Lightning_bolt360
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How does gravity work under time reversal and CPT reversal?

Posted: 18 Nov 2019 06:41 AM PST

According to the idea of CPT symmetry a charge, parity and time reversed universe should be indistinguishable from our own. However, I don't really understand how gravity fits into this reversal. It seems like gravitational interactions wouldn't be effected by charge or parity reversal.

For T-symmetry to work (hypothetically) wouldn't gravity have to be reversed? How does CPT reversal lead to normal gravity if this is the case?

submitted by /u/Anaklusmos
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Do thermochromic leuco dyes go from transparent to translucent or transparent to opaque?

Posted: 18 Nov 2019 11:20 AM PST

I'm reading: https://scienceprojectideasforkids.com/thermochromic-dyes/

As it mentions here, in one state thermochromic dyes (both hot and cold?) are able to be transparent so that light can pass through them. (Is this true?)

Does the state of a thermochromic leuco dye go from transparent to translucent, or can it go fully opaque? (in colour)

So that no light is passing through?

As in - transparent to an opaque color, back to transparent.

submitted by /u/StinkyProfessor
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Why is Hepcidin released in case of inflammation, so all iron-ions are kept inside of mucosa cells due to degeneration of Ferroportin-Channels and even iron intake in other tissues is reduced due to degeneration of Transferrin-Receptors?

Posted: 18 Nov 2019 10:13 AM PST

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