What happens when a cloud is full?

As part of our water study we investigated what happens when a cloud is full?  We used water in a cup to represent air,  shaving foam for the cloud and blue dye for water. We found out that when the water evaporates back up to the clouds they condense and became very full and heavy. When the cloud can hold no more water it bursts open and we have rain or as we like to call it in room 2 precipitation! The children are finding out some wonderful information through investigating.