PBS
Pbs Learning Media: Continental Drift: What's the Big Idea?
Students learn how the theory that explains the position of Earth's continents was established and later modified.
CK-12 Foundation
Ck 12: Earth Science: Earthquake Characteristics Study Guide
This comprehensive study guide covers the main terms and concepts needed for an earth science unit on the characteristics of earthquakes. Review questions are included at the bottom of the study guide.