Students will learn that the earth surface is made up of plates, which shift and collide causing earthquakes and volcanoes.

Procedures:

1. Discuss with the students that the earth is spherical like an orange, but that we cannot see the roundness of our own earth unless we are looking at it from outer space.

2. Instruct the students to peel the orange without the use of a knife and in as few pieces as possible. This peel represents the part of the earth called the crust. The crust is in pieces as is the peel of the orange.
3. Discuss the "flatness" of each section of peel. The peel does not appear to be as round as when it was wrapped around the orange in one piece.
4. Have the students replace the peel on the orange, securing it with toothpicks. Think of this as a spherical jigsaw puzzle.
5. Once the pieces of the peel are back on the orange, it can be pointed out that this is now a more accurate representation of the earth’s crust (i.e. an opportunity to discuss plate tectonics). The cracks in the peel are "faults" or "spreading centers" or "subduction zones" where the earth’s plates) pieces of orange peel) shift and collide causing earthquakes and volcanoes.

** Since the "fault lines" or "plate boundaries" (edges of the peel pieces) are not always evident, another exercise would be to have the students roll out a piece of clay as flat as possible like a pie crust. Then carefully remove the toothpicks while covering the orange with clay. After the orange is covered and the clay is firmly pressed on the orange, remove the clay from the orange to reveal the "plate boundaries".