Liquid Water Lower Than 0°C In A Vacuum?

Reldar

Reldar

Reldar

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Is it possible to have liquid water at a colder temperature than 0°C?

My theory is that if the water is inside a vacuum then it would not have the surrounding air pressure (that is present in our atmosphere) to aid in the compression.

Would it be possible to have liquid water at e.g. -1°C ?
 
I can't remember much from A level physics, but this is the equation for working it out. :)
pv=nrt
Presure*volume=(# of moles)*(constant r)*temperature
 
No (well not in a vacuum anyway ;))

As pressure decreases the freezing point increases not decreases.

The freezing point of water at one atmosphere pressure is 273.15 Kelvin or 0C. As the pressure is lowered, the freezing point increases ever so slightly, to 273.16 Kelvin or 0.01C. This is at a very low pressure of 0.006 atmospheres (1 atmosphere is normal pressure). Below this pressure, liquid water is not stable. Only the gas and solid are stable.
If you subject water to a hard vacuum, it will boil until it loses enough heat to make the remaining liquid freeze solid.

Here are the phase diagrams for water:

http://www.lsbu.ac.uk/water/phase.html
 
Last edited:
alx said:
I think you mean if the pressure is low enough....;)

Lower atmospheric pressure = less resistance to evaporate
Click to expand...

This. Which is why you can't make a cup of tea at the summit of Mount Everest. The water boils long before it is hot enough to diffuse the tea leaves ;)
 
Changing the pressure of a liquid is the basis of phase-cooling, except it goes one step further and causes the liquid to evaporate removing a lot more heat.

If you google long enough you can find all the information and parts needed to build your own phase-cooling system

MW
 
You can chill water to below 0 degrees, something to do with absolutely no movement - knocking the container causes the ice to rapidly form over a second.

Or something.

i think.

Something to do with not having a seed ice crystal.

edit:
 
liquid water under 0 C?

what you want is non-boiling pure water at sea level over 100 c, then add a spoon (dont try this it explodes everywhere)
 
I've done that and its really cool.
Very pure water superchilled give it a tap and it sets solid.

As stated above you need a set of phase diagrams.
I hated phase equilibrium when i was doing my A-levels and then I went on to spend 4 years getting a chemical engineering degree, go figure eh?
 
tres said:
You can chill water to below 0 degrees, something to do with absolutely no movement - knocking the container causes the ice to rapidly form over a second.

Or something.

i think.

Something to do with not having a seed ice crystal.

edit:
Click to expand...

That's supercooling. There's also superheating. http://en.wikipedia.org/wiki/Superheating

All pretty cool stuff. Pardon the pun. :p
 
House said:
I've done that and its really cool.
Very pure water superchilled give it a tap and it sets solid.

As stated above you need a set of phase diagrams.
I hated phase equilibrium when i was doing my A-levels and then I went on to spend 4 years getting a chemical engineering degree, go figure eh?
Click to expand...

Oh yes, I still remember the example phase diagram showing the 6+ different types of ice! :o
 
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