In the last segment of the first adventure, which covers Earth Formation, I created the following movie clip to illustrate the Earth's crustal plates.
The process of plate tectonics involves the large scale motions of the Earth’s crust. The crust and the portion of the mantle connected to it (lithosphere) are broken up into several large and many minor plates. These crustal sections ride and float on top of the molten portion of the mantle (asthenosphere).. There are actually two types of crust that make up these plates. There is the lighter and thicker continental crust and the denser and thinner ocean crust. The ocean floors are continually moving, spreading from the mid-ocean ridges, sinking at the edges, and being regenerated. Convection currents beneath the plates move the crustal plates in different directions. The source of heat driving the convection currents is radioactivity deep in the Earth’s mantle.
The movement of the Earth's plates explains the cause of earthquakes, volcanoes, oceanic trenches, mountain range formation, and many other geologic phenomenons. The plates are moving at a speed that has been estimated to be up to six inches per year (15 cm) depending on the plate, but averages around an inch and a half (3.8 cm).
This is just a sample of the informatoin included in the online rockhounding adventures. The references for this sample are: