How do forces in Earth’s interior determine what will happen to the surface we see? This unit is designed to help students build an intuitive understanding of the relationship between energy transfer and unbalanced forces as they explore science ideas related to plate tectonics, radioactivity, convection, and rock formation.

Students read about a crack that opened up suddenly in the Afar region of Ethiopia in 2005, accompanied by earthquakes and volcanos. They compare this to other earthquake events that occur in North America. This prompts them to model the events that occurred before, during, and after the crack was discovered. They figure out that changes in the structure of matter involve unbalanced forces and energy transfer, and use this idea to explain earthquakes and volcanoes at plate boundaries. They explore Earth’s interior using tomography and modeling, including radioactivity, to explain the unbalanced forces driving changes in Earth’s crust. They then investigate the interactions happening at plate boundaries and the nature of the relationship between mass and forces on the movement of tectonic plates to explain the past, present, and potential future of the Afar region. Finally, students apply these ideas in a transfer task to explain why a rift similar to the rift in the Afar region failed to create an ocean in the middle of North America 1.1 billion years ago.