PPT Slide
Notes:
Another quality of the lithosphere is that it is not one solid piece but is composed of more than a dozen pieces, called plates that fit together like the pieces of a jigsaw puzzle. These plates can move independently of one another and this movement is called continental drift. (Their movement can be compared to a conveyor belt, with the plates carrying along the continents, coral reefs, and volcanic islands.) The slow movement is powered by convection currents caused by the tremendous heat at the earth's center, and by the creation of new crust.