Hello all. Consider the case whereby one brings out a cold drink on a hot day. Why do water droplets form on the surface of the cold glass? I would think that when water molecules in the gaseous state collide with the glass surface, they transfer some energy into the glass. Therefore by the surface of the glass, water molecules lose enough energy to form bonds with other molecules (they couldn't before since they had too much energy), eventually resulting in a droplet. Here is where I'm a little lost... why wouldn't condensation, then, occur if both the air and the glass were the same temperature as the glass in the former example? Basically, lets assume that the water molecule has energy X after interacting with the glass in the example above. Why wouldn't a gas of water molecules at temperature T of energy X simply condense on any surface, also of temperature T, since their energy is low enough to coagulate with other water molecules?