Suppose an astronaut on the surface of the moon took some water at about `20^@C` out of his thermos and poured it into a glass bbeaker. What would happen to the water?

Explanation

The external pressure being almost zero, some of the water would evaporate quickly. The evaporating water would take its latent heat of vapourization from the remaining water. Hence, the remaining water would first cool to `0^@C` and then freeze. Thus, ultimately, a part of the water would evaporate and the rest would freeze.
This establishes the condition that a liquid cannot exist in an extended vacuum.