Science Buddies
Science Buddies: Get Down and Dirty: How Does Soil Change With Depth?
What covers less than 10% of the Earth's surface, yet is a vital natural resource for terrestrial life? What filters ground water and supports most of our food production, not to mention the production of building materials and paper?...
CK-12 Foundation
Ck 12: Fourth Grade Science: Earth Science: Theory of Plate Tectonics
[Free Registration/Login may be required to access all resource tools.] Discusses what a tectonic plate is and how scientists can recognize its edges, how the plates move by convection in the mantle, the three types of plate boundaries...