Students read about Earth’s structure. They find out about the slowly moving plates that make up Earth’s surface and how they are related to mountain building, trenches, earthquakes, and volcanoes. They learn about physical and chemical weathering and how they contribute to soil formation. They are introduced to the causes of erosion and deposition and the landforms that are the results of these forces. They also read about soil conservationists and the ways they work to conserve soil and control erosion. Finally, students learn about floods.