In prior grades students learned how Earth materials change and how they can be used for various purposes. In grades 6-8 students learn about planet Earth as an interacting system of solids, liquids, and gases. Solar energy powers the water cycle and drives the weather system and ocean currents. Energy from within the planet drives the rock cycle and moves huge plates on the Earth’s surface, causing earthquakes and volcanoes. The landforms we see today result from processes that build up and break down Earth structures. These fundamental ideas will enable students to understand the history of their planet, Earth processes occurring today, and future geologic events.