In Reply to: ice in a vacuum posted by paul styler on 03/24/03 at 5:41 AM:
Water in a vacuum will start to boil at 68F
when a vacuum of 23.4 mbar or 18 torr is reached.
As long as any water exists at room temperature
anywhere in a vacuum system,the minimum pressure
attainable in the system will be 23.4 mbar or 18 torr ( this is called the saturated vapour pressure).
A little water will produce very large volumes of vapour,and can take a long time to pump away.
Note that rapid evaporation will result in a lowering of the tempreture of the water ( unless
heat is applied ) and it will freeze.
At 32F the saturated vapour pressure of ice is about 6mbar or 4.5 torr.
I hope this answers your question