The water molecules slow down, stronger attractions form between them, and the molecules are pulled closer together.
Explanation:
In solids the packing of the particles is closer and tighter thus increasing the intermolecular attraction. This makes solids rigid with a definite shape, size and volume. On the other hand in liquids the packing of the particles is loose thus decreasing the intermolecular attraction. This makes liquids able to flow, and takes the shape and volume of the container in which they are placed.
A. Air expands, becomes less dense and rises when the temperature is high due to the increased kinetic energy. This causes the air molecules to move around much more so they are further apart.
