Watch the Water Cycle in a Bag
A clear plastic ziplock type bag
A little water
1. Put a small amount of water in the bag, then blow into the bag and try to trap some of the air in the bag whilst sealing it.
2. Place the bag on a sunny window sill, or over a radiator.
Some of the water will evaporate, rise and condense on the sides of the bag, and then run back down to join the water in the bottom of the bag. This is a simplified, miniature version of what happens in the atmosphere. The water at the bottom of the bag is like a sea or ocean, the condensation on the sides of the bag is like clouds, and the water running down the sides of the bag is like rain.
Why not draw a simplified picture of the water cycle on the outside of the bag? It should show the sea/ lakes/ rivers, evaporation, condensation, clouds and precipitation.