Dear Daniel,
We all know that if you heat water up, it will
boil. What you may not know is that the temperature at which water (or
any liquid) will boil depends on the atmospheric pressure.
Water
actually boils at a lower temperature if the pressure around it is
lowered. This is why if you go to a high altitude location (like many
parts of New Mexico), where the atmospheric pressure is lower, water
will boil at slightly less than 100 degrees C.
In a vacuum chamber, the pressure can be extremely low. So low, in fact, that water can actually boil at room temperature.
So,
if you put some water in a high-vacuum chamber you will see it boil.
(Then, with all that water vapor around, it won't be a high vacuum
anymore!)
(published on 10/22/2007)
