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General Science => General Science => Topic started by: neilep on 25/09/2004 18:28:22

Title: How Dense Can Water Get? Can water under pressure become a solid?
Post by: neilep on 25/09/2004 18:28:22
Under Pressure....great tune by Queen and David Bowie but can water be under so much pressure that it can effectively become more viscous or solid ?...I know that in the deepest ocean the pressure is 16,000 pounds per square inch but there never seems to be an indication that the water itself is squashed !!!

Release that tension and let the answer be all runny and gooey.

 Many Thanks


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Title: Re: How Dense Can Water Get? Can water under pressure become a solid?
Post by: DrN on 26/09/2004 21:29:59
Hi, water is pretty special, it is actually less dense as a solid than it is at 4 C - liquid! something to do with the rigid bonds that make the solid pushing the H2O molecules further apart than when they were just a pretty cool liquid. as it heats up above 4 C i think it becomes less dense again, probably something to do with the extra energy causing the molecules to buzz around. I can't really remember it all exactly!

If i remember rightly this amazing property of water is due to its dipole, the charges on the hydrogens and oxygen are unevenly distributed, so electrostatic interactions form - hydrogen bonds.

to be honest, I've got no idea if water can be condensed under pressure. because I've what I've said above i would guess it would have to remain a liquid in any case.

i hope someone can enlighten you a little more than I'm able to!
Title: Re: How Dense Can Water Get? Can water under pressure become a solid?
Post by: qpan on 26/09/2004 22:30:50
Water is less dense in solid form due to hydrogen bonding - without this special type of bonding, life would probably not exist as instead of ice forming on the surface of water and creating an insulating layer, it would sink to the bottom causing far quicker freezing of all the water.

Water is very difficult to compress, like all liquids. In very deep areas of sea (1-2 miles deep) the water pressure compresses the height of the sea by only several metres (5-10 metres)!

"I have great faith in fools; self-confidence my friends call it."
-Edgar Allan Poe
Title: Re: How Dense Can Water Get? Can water under pressure become a solid?
Post by: OmnipotentOne on 27/09/2004 02:23:17
I know this really isnt an answer, but I remember watching cartoons and such where they dived so deep in the sea that eventually they crashed through a ceiling of water and ended up in a cave.  They would get out of there sub, look around to see water flowing upward into the semi solid wall of h2o above.


I wonder if its possible....[?]

To see a world in a grain of sand.
Title: Re: How Dense Can Water Get? Can water under pressure become a solid?
Post by: Broca on 29/09/2004 19:37:28
http://www.nature.com/news/2004/040920/full/040920-2.html
Title: Re: How Dense Can Water Get? Can water under pressure become a solid?
Post by: neilep on 29/09/2004 20:25:03
Thanks for the link Broca......that's about as gooey as you can get !..thanks

'Men are the same as women...just inside out !' (https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fwww.world-of-smilies.de%2Fhtml%2Fimages%2Fsmilies%2FSchilder2%2Finsanes.gif&hash=4f18432872d0188852a6f4a3170ec758)
Title: Re: How Dense Can Water Get? Can water under pressure become a solid?
Post by: Broca on 30/09/2004 00:40:58
Your welcome Neil...I tossed it on without much fanfare this afternoon...but when I saw it, sad to say, I thought of you! :-) I found the results of that study most amazing, not what you would have thought.
Title: Re: How Dense Can Water Get? Can water under pressure become a solid?
Post by: Monox D. I-Fly on 26/01/2018 03:17:27
http://www.nature.com/news/2004/040920/full/040920-2.html
"The best swimmer should have the body of a snake and the arms of a gorilla," recommends Cussler.

So that's why gators are excellent swimmers.
Title: Re: How Dense Can Water Get? Can water under pressure become a solid?
Post by: Petrochemicals on 26/01/2018 04:50:43
Water is a strange substance, very light comparitavley but a huge thermal capacity, and as has been stated large in volume r in its hexagonao form ice than as liquid. Has a triple point of zero, and exists as a vapour and a solid beneath freezing in standard pressure of earth.

Liquid water on earth becomes more d3nse toward about 4 degrees and then becomes less dense as you approach 100c.

Super cooling water under standard pressure leads to water below freezing by some way, and this leads to glasy ice, with no cristaline s5ructure, only amphimorous glass like structure. Super cooled water is slightly d3nser than standard 1g cc.

Pressurizing water and heating it can lead to high temperature ice that is solid at room temperature and atmospheric pressure , and the only way to return it to normal phaze h20 is to heat it further.

Water compresses slightly so i would say that greatest density is probably under huge pressure at 4 degrees. Although this pressure will undoubtably move the scales so illl take a guess at about 30 dcentigrade at a black smoker.
Title: Re: How Dense Can Water Get? Can water under pressure become a solid?
Post by: Kryptid on 26/01/2018 17:34:21
With sufficient pressure, you could probably turn water into degenerate matter (like that which exists inside of white dwarf stars). That would be a density of 104 - 107 g/cc. This assumes that you keep the temperature low enough in the process to keep the hydrogen in the water from fusing, of course.
Title: Re: How Dense Can Water Get? Can water under pressure become a solid?
Post by: wolfekeeper on 26/01/2018 18:08:59
You're asking multiple questions here, including whether it can be solid under pressure. I don't think the density of water changes that much with pressure, but ice exists in very many different forms. I think about the densest is Ice XII which is 1.3 times the density of water:

https://en.wikipedia.org/wiki/Ice_XII

It forms at pressures of 5400 atmospheres at -13C. However, it's only metastable. I'm not sure whether you can have it at normal pressures, if so you could drop it into water and it would readily sink!

The phase diagram for water/ice is complicated:

(https://upload.wikimedia.org/wikipedia/commons/thumb/0/08/Phase_diagram_of_water.svg/1088px-Phase_diagram_of_water.svg.png)

(note that ice XII isn't on this diagram, apparently because it's metastable.)

More at ice:

https://en.wikipedia.org/wiki/Ice
Title: Re: How Dense Can Water Get? Can water under pressure become a solid?
Post by: Bored chemist on 26/01/2018 18:33:57
You're asking multiple questions here,
They were asking multiple questions- a dozen years or so ago.
Title: Re: How Dense Can Water Get? Can water under pressure become a solid?
Post by: wolfekeeper on 26/01/2018 19:13:56
And still nobody had really answered it!
Title: Re: How Dense Can Water Get? Can water under pressure become a solid?
Post by: chris on 26/01/2018 22:01:22
You're asking multiple questions here,
They were asking multiple questions- a dozen years or so ago.

It's terrific that we're revisiting some of these ancient gems, which date from the very early days of the Naked Scientists - amazing really that many of us are still here and still doing this!

Right, shall we try and answer it!?
Title: Re: How Dense Can Water Get? Can water under pressure become a solid?
Post by: alancalverd on 27/01/2018 08:40:04
I think Wolfekeeper's phase diagram answers the question regarding solidification at high temperatures. Under ambient conditions the liquid compresses at about 0.5% per atmosphere additional pressure, so the density of "normal" water can indeed vary a bit, and at 1000 atm or at the bottom of the sea it will indeed be substantially denser than the stuff in your tap.
Title: Re: How Dense Can Water Get? Can water under pressure become a solid?
Post by: chris on 27/01/2018 09:36:47
I think Wolfekeeper's phase diagram answers the question regarding solidification at high temperatures. Under ambient conditions the liquid compresses at about 0.5% per atmosphere additional pressure, so the density of "normal" water can indeed vary a bit, and at 1000 atm or at the bottom of the sea it will indeed be substantially denser than the stuff in your tap.

Alan - when we say in physics lessons that liquids are incompressible, is that a small lie? For water to become denser at greater depth, as we know it does and as you have mentioned above, then it must be compressing a bit. So are physics teachers lying when they say this?!
Title: Re: How Dense Can Water Get? Can water under pressure become a solid?
Post by: wolfekeeper on 27/01/2018 15:06:09
Well, they usually say it's almost incompressible. The compressibility of water is about 1% at 200 atmospheres (compressibility varies, but is about 4.4 to 5.1 x 10^-10/Pa). So for example, the pressure at 11km depth at the bottom of the Mariana Trench is about 1000 atmosphere, so the water will be compressed about 5%.

Actually if you look at the diagram, if you just increase the pressure from normal liquid water, along most of the curve you find you form Ice VI, which, while not metastable, is also interesting:

http://www1.lsbu.ac.uk/water/ice_vi.html

If you read the page, it too has a slightly higher density than water, even the high pressure water around it which has been compressed, so it too would sink.

Unfortunately that would take several times the pressure to form than you find at the bottom of the Mariana Trench, so humans will never see a snowy bottom in our Bathyspheres.
Title: Re: How Dense Can Water Get? Can water under pressure become a solid?
Post by: alancalverd on 28/01/2018 09:48:00
Alan - when we say in physics lessons that liquids are incompressible, is that a small lie? For water to become denser at greater depth, as we know it does and as you have mentioned above, then it must be compressing a bit. So are physics teachers lying when they say this?!

It's only a bit more of a lie than Newtonian physics - the approximation is good enough for everyday use. But if a substance were truly incompressible, the speed of sound would be infinite as every molecule would have to move at the same time.
Title: Re: How Dense Can Water Get? Can water under pressure become a solid?
Post by: chris on 28/01/2018 09:50:04
if a substance were truly incompressible, the speed of sound would be infinite as every molecule would have to move at the same time.

Thank you for that excellent point - I'd not made that obvious connection in my own mind.
Title: Re: How Dense Can Water Get? Can water under pressure become a solid?
Post by: alancalverd on 28/01/2018 09:51:11
Unfortunately


No, it's very fortunate! If the oceans froze from the bottom upwards,the climate would be very different and life would probably not have evolved.

Almost every terrestrial phenomenon that is ascribed to God is actually caused by the hydrogen bond.
Title: Re: How Dense Can Water Get? Can water under pressure become a solid?
Post by: chris on 28/01/2018 09:52:21
humans will never see a snowy bottom in our Bathyspheres.

Probably a good thing!

Taking the thought experiment a bit further on then,  if we did have a sufficiently deep ocean, would the underwater ice form up to a depth at which the pressure became to low to sustain it as a solid? So you would have a solid water ocean floor beyond a threshold depth?
Title: Re: How Dense Can Water Get? Can water under pressure become a solid?
Post by: puppypower on 28/01/2018 12:30:16
Water expands when it freezes into solid ice. This is why ice floats on liquid water. When we add pressure, we cause liquid water to contract, which can prevent the water from expanding into ice. Liquid water can exist down to about -55F by adding pressure because the pressure will not allow the water to expand into ice. At -55F the lack of expansion is compensated by the slow mobility of the water molecules, such that it no longer has the entropy of a liquid. A metastable solid can form.

This strange behavior is due to the unique properties of hydrogen bonding. Hydrogen bonding shows both covalent and polar character. As a polar bond, the EMF or electromagnetic force potential is lowered by the hydrogen bonds getting as close as possible; minimize charge potential. As a covalent bond, the hydrogen bond needs to expand, so the covalent bonding orbitals can overlap properly. Pressure keeps the hydrogen bonds from expanding, such that they remain more polar, unable to expand into the needed covalent orientations for ice.

This shift in hydrogen bonding between polar and covalent states is important to life. It allows high and low density water clusters to form in then continuous liquid water phase within life.  If the local water expands via a covalent dominate cluster, this can put the squeeze on a local enzyme, so it can't move property to function, If the cluster shifts more polar and thereby contracts, now the enzyme is loose and can react. Information moving through the water, via hydro bonding, has a physical consequence.

If we maintained pressure and continued to add heat,the heat will eventually cause the polar bonds to expand, allowing solid water to form at high temperatures and high pressures. If we continue to add temperature, eventually the hydrogen bonds start to break, such that the polar and covalent transition is moot. This water above its critical point. Hydrothermal water; above the critical point, is very corrosive to most minerals and grinds down organics to CO2.

If we continue to add even more temperature and pressure, water undergoes several additional phases changes into exotic phases. The first is superionic water, then ionic water, and then liquid metal water, and final solid metallic water, which has a density of about 3.5 grams/cc.

In metallic water, the oxygen atoms of water form the stationary matrix of the water metal. The hydrogen protons are able to move, similar to the way elections move in most metals. Along with the hydrogen protons, are mobile electrons. Metallic water is a metal composed of an oxygen matrix, that conducts electricity using a plasma of hydrogen protons and hydrogen atoms.

Metallic water can theoretically exist in the core of the earth. The conditions of the core are within the parameters of the metallic water phase. The hydrogen proton plasma current of liquid and metallic water would be very corrosive to the metallic iron in the core. The oxygen matrix can accommodate extra elections, with the plasma hydrogen fetching elections from the iron. The earth has large supply of natural internal energy, proportional to the amount of iron in the earth's core. The liquid and metallic water will attempt to amalgamate with the iron, with the hydrogen of metallic water putting irons elections into play. This is reflected in the slight negative charge of the oceans.
Title: Re: How Dense Can Water Get? Can water under pressure become a solid?
Post by: wolfekeeper on 28/01/2018 23:17:00
humans will never see a snowy bottom in our Bathyspheres.

Probably a good thing!

Taking the thought experiment a bit further on then,  if we did have a sufficiently deep ocean, would the underwater ice form up to a depth at which the pressure became to low to sustain it as a solid? So you would have a solid water ocean floor beyond a threshold depth?
Yes, that's what I meant, you'd get Ice VI forming at great depth, depending a bit on the temperature down there, and it would stay down there because Ice VI is denser than water at the same pressure and it needs the high pressure to stay solid.

Unfortunately
No, it's very fortunate! If the oceans froze from the bottom upwards,the climate would be very different and life would probably not have evolved.
That's true, but I'm talking about Ice VI which can only form and be maintained under very high pressure, but (unlike Ice V) appears at temperatures well above freezing. So you could end up, as Chris says, with a layer of Ice VI as the new sea floor but only at great depth where the pressure is high enough.