1Fill the large bowl with water (about 1/2 inch deep).
2Add the grass and dirt.
3Place the smaller bowl in the middle of the big one (should be at least 3x size difference).
3Cover the large bowl with plastic wrap and secure it with the rubber band.
4Place the coins in the center of the plastic wrap so it slants down towards the small bowl.
5Place the bowl outside in the sun for a few hours.
Tip 1:The more surface area the water has to evaporate, the faster it works.
Tip 2:If you do not have a hot & sunny day, you can simulate it by using very hot water (teachers only).
How It Works
When the liquid water in the large bowl is warmed by the sun, it evaporates into water vapor. The water vapor rises up until it touches the cooler plastic wrap. That causes the water vapor to cool down and condense to form water droplets on the plastic wrap. When the droplets get big enough, they roll down the slanted plastic wrap to the lowest point and fall into the smaller bowl. The grass and dirt do not evaporate, so they are left behind in the large bowl. The process happens slowly, and is constantly cycling on Earth.
Check out the Full Lesson on Water Cycle (3-5 Version)!
In this lesson, we learn that:
Water on Earth is millions of years old and is constantly being recycled.
Water vapor is constantly evaporating from the surface of the Earth.