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Freezing water...

I

imported_goku

Diamond Member
What would happen if you fill up a high strength container (titanium?) with water completely, seal it and then freeze it? When I mean seal it, you seal it with a weld or something. Is it possible? Does it have to burst?
 
Have you ever filled a water bottle and put it in the freezer for quick cooling, then forgot about it? It gets kinda lumpy all over, with the water expansion. My guess is that the same thing would happen. Of course, it depends on how thick the metal is and how pliable the metal is. I don't really know what would happen if the metal was thick enough and hard enough not to bend a little. Nalgene bottles are pretty hard, try it with one of those. ;-)
 
the container would expand and the ice would be slightly compressed. this is true for every situation. the amount the container deformed would be a function of its material properties and thickness. liquids and solids are mostly incompressible, so the outward force would be felt by the container.
 
So I think about it again and remember stress from Physics 2.
In order to change the density of the solid water, the force exerted by the container would have to be huge.
P=B*abs(?V/V), where B is a constant called the bulk modulus. A quick Google search didn't really find the bulk modulus of ice, but if we assume that it's 50% that of steel, it would still be 8*10^10 N/m^2. So say we have a 1 L container filled with water. When frozen, the ice would want to take up 1.086L, so ?V=.086L
Solving with our arbitrary B, the pressure exerted by the container is 6.88*10^9 Pa. Which is ginormous, very close to a million pounds per square inch.
 
Is it possible that, if the container were sufficiently strong, the water wouldn't be able to freeze? This might be totally stupid, but I know that you can raise water above boiling if you keep the pressure high enough - like in pressure cookers.

Groups of water molecules have a lot of empty space in them when water crystallizes, hence the lower density of ice vs liquid water. Assuming the water were not allowed to expand, would some of it remain a liquid?
 
Originally posted by: Jeff7
Is it possible that, if the container were sufficiently strong, the water wouldn't be able to freeze? This might be totally stupid, but I know that you can raise water above boiling if you keep the pressure high enough - like in pressure cookers.

Groups of water molecules have a lot of empty space in them when water crystallizes, hence the lower density of ice vs liquid water. Assuming the water were not allowed to expand, would some of it remain a liquid?
Click to expand...
It probably freezes solid.

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The link posted above is pretty interesting.

Basically: up to a certain point, increased pressure makes the water's freezing point go down (this is how ice skates work), but at absurdly high pressures it just freezes and becomes super-dense ice.

So if you put water into a truly 'immutable' container and lowered the temperature enough, it would freeze in place without expanding. I can't imagine any 'normal' material could take that kind of stress, though, especially at really low temperatures. Most metals would become brittle enough to fracture, I would think... maybe carbon fiber, or synthetic diamond, or something? Dang, I knew I should have taken materials science... 😛
 
Originally posted by: Gibsons
Originally posted by: Jeff7
Is it possible that, if the container were sufficiently strong, the water wouldn't be able to freeze? This might be totally stupid, but I know that you can raise water above boiling if you keep the pressure high enough - like in pressure cookers.

Groups of water molecules have a lot of empty space in them when water crystallizes, hence the lower density of ice vs liquid water. Assuming the water were not allowed to expand, would some of it remain a liquid?
Click to expand...
It probably freezes solid.

Text
Click to expand...

Ah, but I was sort of right - depends on the pressure. So only in a few scenarios will it fail to freeze.

Nifty diagrams there. Interesting that at some pressures, it looks like water will simply sublimate.
And my god, you'd never think water could be so complicated. That page just starts to look nuts as you scroll down. Wow.
 
Originally posted by: Matthias99
The link posted above is pretty interesting.

Basically: up to a certain point, increased pressure makes the water's freezing point go down (this is how ice skates work), but at absurdly high pressures it just freezes and becomes super-dense ice.

So if you put water into a truly 'immutable' container and lowered the temperature enough, it would freeze in place without expanding. I can't imagine any 'normal' material could take that kind of stress, though, especially at really low temperatures. Most metals would become brittle enough to fracture, I would think... maybe carbon fiber, or synthetic diamond, or something? Dang, I knew I should have taken materials science... 😛
Click to expand...

While diamond is extremely tough t oscratch, it is not so resistant at other kind of damage (shocks, and possibly extension)
 
Originally posted by: Jeff7
Interesting that at some pressures, it looks like water will simply sublimate.
Click to expand...

I'm surprised that you've never seen this in high school chem....

Our chem teacher would bust out the bell jar and do a little demo of the phase change diagram for water. We got to see sublimation, freezing at room temp, and the triple point. Very cool at the time... made an impression.
 
If the tank, or what ever it was was strong enough, I don't think the water could turn into ice. But in anycase it sounds like it would be a fun test to run.
 
depending ont he container...
the water will start to solidify into ice crystals, it wont be one crystal for obvious reasons.
as the crystal structures form, the over all volume will increase due to the shape of the water molecules and the crystaline structure of water being more spread out than liquid.

if the titanium container is THICK enough, the ice will be compressed.
if the titanium container is not as thick, it may expand some.
titanium is very brittle, due to its hardness, and there will be a range of thicknesses where it will just crack due to the forces involved (surface tension, and the water expansion).
this is especially true since the freezing of water only happens at low temperatures. and it may take even colder temperatures to freeze the water in that compressed state.
 
freezing water can crumble solid stone, can break apart sunken ships... no titanium container would be able to hold that expansion. this assumes that the water is actually freezing. if you do find a container that can hold it (like welding the open end of a cannon in on itself), the watter simply will not freeze if it cannot expand. you have to exert more inward pressure than molecualr expansion pressure. the water would simply become supercooled.

imagine the 3-phase diagram showing gas, liquid and solid temps for water... place water in a sealed continaer that will not budge, and the line for liquid-solid will jut far to the right
 
Originally posted by: mdchesne
freezing water can crumble solid stone, can break apart sunken ships... no titanium container would be able to hold that expansion. this assumes that the water is actually freezing. if you do find a container that can hold it (like welding the open end of a cannon in on itself), the watter simply will not freeze if it cannot expand. you have to exert more inward pressure than molecualr expansion pressure. the water would simply become supercooled.

imagine the 3-phase diagram showing gas, liquid and solid temps for water... place water in a sealed continaer that will not budge, and the line for liquid-solid will jut far to the right
Click to expand...

There's a pretty detailed phase diagram in the link I posted above.

What's interesting (IMO) is that if you cool water to about -40C, it's going to freeze solid, even at a 10^12 Pa (that's like a million atmospheres? (disclaimer: I haven't checked this so I might be off by a few orders of magnitude 😉 )). Anyway, there are very few materials that can take that kind of pressure. Even generating the data to make that phase diagram isn't simple... I suspect it's done with the way-cool diamond anvil things.
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When water freezes the bond lengths elongate slightly. This is due to increased hydrogen bonding in the frozen water. When ice melts, some of the hydrogen bonds break allowing water to have its fluid movement.....it is about 10% denser as a liquid than as a solid(ice).

"Is it possible that, if the container were sufficiently strong, the water wouldn't be able to freeze? This might be totally stupid, but I know that you can raise water above boiling if you keep the pressure high enough - like in pressure cookers."

Was just thinking about that when I read your post.....I think you may be right.....to freeze, water needs to expand so you would have a certain amount of ice surrounded by some water...I feel that there would be a lot of repulsion between oxygen atoms if sufficient compression was attained which would keep the water fluid

 
How thick is this tin.....
1 mm..thick..............at 100mm..height...............50mm..wide...

titanium will not even buckle under that piss weak test, ice will be forced by the science in the metal and its structure to become pressureised , titanium is awsome stuff, the water will freeze no problems, the water will melt no problem, if perfectly sealed, the energy content will stay the same.....kj.....
 
If the container is strong enough, it will form dense ice (Either ice-II or ice-III depending on the temperature), or more likely a mixture of normal and dense ices will form.

Looking at the phase diagrams (link above) it appears this transition will take place at about 200 MPa (approx 30,000 psi of pressure). High pressure certainly, but not that high - similar pressures are sometimes used on large scales in heavy industry.
 
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