[thedoc (OP)]

Can you mix water with something to stop it expanding when it freezes?
Asked by Android Neox, 2nd Life


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[thedoc (OP)]

We answered this question on the show...



Water and glycerol have really fantastic properties.  You can freeze water, as we know, at around 0°C whereas glycerol, pure glycerol, freezes at a much higher temperature.  If you mix the two components together, you can actually reduce the freezing temperature to below 0.  I believe at a concentration of 0.3 mole fraction, so 30% glycerol, 70% water, you can get the freezing temperature of that solution, all the way down to -45°C.  now what's that doing to the actual hydrogen bonded network of water, that's exactly what we’re trying to find out, using this neutron diffraction technique.

[damocles]

With all due respect, I think that this answer does not really address the question. Stopping water from freezing until you reach a really low temperature is not quite the same thing as stopping it from expanding when it does freeze (at that really low temperature).

When your 'really fantastic' 70:30 water:glycerol mixture does freeze at -45°C, what are the densities of the liquid and ice phases? Does the mixture shrink or expand upon freezing?

[Geezer]

I suspect that if you can prevent water from expanding as its temperature drops below 0°C, it won't actually freeze.

[CZARCAR]

if ice is expansive due to the ionic nature of the H2O molecules repelling each other as they slow with cooling,wouldnt a magnetic suspension additive, opposite of the H2O charge, negate the repelling effect & result in minimized expansion of ice?

[The Penguin]

The answer is no. You cannot.

[Bored chemist]

Yes, you can, you have to apply a lot of pressure.

[CliffordK]

Yes, you can, you have to apply a lot of pressure.

There are supposed to be 9 different types of ice depending on conditions.

http://www.windows2universe.org/jupiter/moons/nine_kinds_of_ice.html


http://www.enm.bris.ac.uk/teaching/projects/2002_03/jb8355/review.html


Anyway, I'm having troubles orienting myself on the phase diagrams. 

I doubt that the typical Ice-1 is forming without expansion, but at extreme pressures, different ice crystal structures are forming.

[The Penguin]

Yes, you can, you have to apply a lot of pressure.

Is it only theoretically possible, or can we actually provide that type of pressure and containment?

Thanks!

[CliffordK]

Here is a lot of good information about different types of ice.

http://www.btinternet.com/~martin.chaplin/phase.html

The following types of ice have densities greater than water, and thus would sink in plain water (unlike our typical low density ice that floats in water).

Ice Two (II) has a density of 1.16 g/cc, greater than that of water.
Ice Three (III) also has a density of 1.16 g/cc
Ice Nine (IX) is also slightly denser than Ice III.
Ice Five (V) has a density of 1.24 g/cc
Ice Six (VI) has a density of 1.31 g/cc
Ice Seven (VII) has a density of about 1.65 g/cc, greater than that of water.
Ice Eight (VIII) has a density of about 1.66 g/cc, also greater than that of water.

Many of the different forms of ice (including most of the high density ices) are formed at high pressures, sometimes at temperatures greater than 0°C. 

Since the physical properties are listed, I would have to believe they have actually been created. 

[Bored chemist]

Yes, you can, you have to apply a lot of pressure.

Is it only theoretically possible, or can we actually provide that type of pressure and containment?

Thanks!

How do you think they drew that diagram? Of course we can do it.

[Airthumbs]

What about surrounding the water with 10 inches of solid steel and then freezing it?  I'd like to see it try to expand then..

[Geezer]

What about surrounding the water with 10 inches of solid steel and then freezing it?  I'd like to see it try to expand then..

I don't know about 10 inches of steel (and I'm too lazy to figure it out!) but water turning into ice will crack cast iron, quite easily. That's why we put antifreeze in cars []

I'm guessing the ice will deform the steel quite a bit.

[CliffordK]

What about surrounding the water with 10 inches of solid steel and then freezing it?  I'd like to see it try to expand then..

I don't know about 10 inches of steel (and I'm too lazy to figure it out!) but water turning into ice will crack cast iron, quite easily. That's why we put antifreeze in cars []

I'm guessing the ice will deform the steel quite a bit.

Cast Iron is brittle.  Steel is much less brittle, although getting it very cold might make it somewhat brittle.  However, the steel would naturally tend to contract when chilled, making your container even smaller.

It would take a lot of force to deform 10" of steel.  I guess it depends on the actual volume of the vessel though.

Anyway, if you managed to freeze ice in a fixed vessel, you would get a mixture of normal ice, and one of the higher density types of ice.

[Geezer]

It would take a lot of force to deform 10" of steel. 

Not as much as you might think. If you whack a piece of steel with a ball pein hammer, you can usually put a decent dent in it, no matter how thick it is. It's really more to do with the hardness of the steel, and if we make it too hard it becomes brittle, and ....

[Airthumbs]

Just a point of interest, does anyone know where you can find ice type 7 on earth?  When I say ice type 7, I am referring to the diagram of the 9 ice types above..

[Bored chemist]

Is there anywhere on earth (outside of research labs) where we know that it's 17000 atmospheres pressure? I don't think the bottom of the oceans is under that pressure, but the earth's core must be. On the other hand, it's hot down there.

Incidentally, one of the ways that research labs generate high pressures is to get a strong steel container with a thin pipe connected to it, fill it with water and freeze it in dry ice. The water forced out through the pipe can be under very high pressure.

[Airthumbs]

Incidentally, one of the ways that research labs generate high pressures is to get a strong steel container with a thin pipe connected to it, fill it with water and freeze it in dry ice. The water forced out through the pipe can be under very high pressure.

That's really cool, no pun intended, how does that work then?  Why would the water be forced out because of the dry ice?

[Bored chemist]

You put the container in dry ice. It gets cold. The water freezes. That ice takes up more space than the water so some gets forced out through the pipe,. If you feed that into a sealed container then the pressure in that vessel rises.

[Geezer]

You put the container in dry ice. It gets cold. The water freezes. That ice takes up more space than the water so some gets forced out through the pipe,. If you feed that into a sealed container then the pressure in that vessel rises.

A very clever idea! I suppose it would work with anything that expands as it freezes, except that there may not be too many of them. Are there any?