This teacher guide presents a unit on plate tectonics and introduces hands-on activities for students in grades 6-8. In each unit, students act as real scientists and gather evidence by using science process skills such as observing, graphing, analyzing data, designing and making models, visualizing, communicating, theorizing, and drawing conclusions. The units presented in this guide meet the National Science Education Standards as well as state frameworks and district guidelines. There are seven sessions focusing on different concepts in the guide. Sessions include: (1) "Geologic Time and Processes That Form the Earth's Crust"; (2) "Field Work of California"; (3) "Investigating Viscosity and Volcanic Rocks"; (4) "Field Work in Hawaii"; (5) "Field Work in Japan"; (6) "Field Work in Nepal"; and (7) "Field Work in Iceland". (YDS)