Why do liquids contract when cooled?
temperature is a measure of kinetic energy, the lower the temperature the less motion in the liquid and the less volume.
As the molecules of a liquid are cooled they slow down. As the molecules slow down they take up less volume. Taking up less room because of the molecules lower energy causes the liquid to contract.
An exception to this is water. As water cools it contracts until it reaches the freezing point. At the freezing point water forms hexagonal crystals that take up more volume that the liquid water. At the freezing point as water becomes a solid water expands.