Why does moisture condense on the outside of a cool glass of water in the summertime?

1 Answer
Jun 6, 2017

When water vapour in air comes in contact with the cool glass, it undergoes a drop in temperature due to transfer of heat to the glass material which is at a lower temperature.

As a result, the chaotic motion of gas molecules become more ordered and thus they come closer.
Then as a result of the intermolecular forces, they condense into water and cling to the glass surface.

That's why moisture condenses on the surface of a cool glass material.