Water Cycle

So now I am going to be teaching the water cycle: evaporation, condensation, precipitation. We are doing 100 ounces of water in a bowl -- representing the salty water of the world. An ice cube of 4 T water frozen -- representing the fresh water in the world which is frozen. 2 T of fresh water in a glass -- representing the fresh water in the world which is in liquid form. Amazing how much of it is salty! I never realized it before this was presented to me in this way.

Anyway, I need to come up with some kind of project to show "mastery" of the water cycle. And I don't want it to be a worksheet. So I'm thinking of some kind of painting and accompanying composition.