Students will understand that the earth is made of different layers.

When you slice an apple, you find different layers. A small core is in the center. A thick layer is in the middle. A thin skin is all around the outside. Scientists can not slice the earth. However, they believe the earth has layers, too. The earth is made of a core in the center, a thick layer in the middle and a thin top layer is around the outside. The top layer is called the crust. Much of the crust is made of rocks. In some places ice and snow may also cover the rocks. In other places deep ocean water may cover the rocks. The small rocks you see on the ground come from the larger rocks of the crust.

Activity: Bring several apples to class. Cut the apples in fourths and have the students find the core, middle sections and skin. (The students love to "eat" this activity after they’ve discussed the similarities between the apple and the earth).

Activity: Display photographs of a variety of places where rocks are found. Include underwater locations, as well as any unusual places you can find rocks. (You may want the students to share pictures they have).

Activity: What would you encounter if you traveled through a tunnel from where you live straight through the earth. Locate on a globe where you would exit the tunnel.