Learn about the earth's layers and plate tectonics by making a model with clay and a tennis ball. Students mold clay to fill the inside of a tennis ball while learning about the fascinating characteristics of all the layers. The tennis ball's structure already mimics the earth's crust as well as finer features such as the lithosphere and asthenosphere. Make this as simple or as involved as you wish by following the basic steps or enhancing the earth with continents. Students will own an earth model that looks like a ball on the outside but surprises everyone when it is opened. Get a bonus idea for students to experiment with at home and additional facts about the various layers for those students and teachers that want to delve into it more.