|Dr. Hartnell's Nutty the A.D.D. Squirrel||
According to the Theory of Plate Tectonics, Earth's surface is composed of about a dozen plates that float on a bed of magma (or molten rock). It resembles a cracked eggshell, and the pieces are moving. The plates include oceans and continents, which move with their plates.
Earthquakes and volcanoes occur where plates push together, spread apart, or slide against one another.
Scientists believe the continents formed a large landmass before they broke apart 200 million years ago and began drifting to their present locations. This "super continent" is called Pangaea [pronounced: Pan-gee-ah].
Earth has seven continents that cover less than a third of its surface: Africa, Antarctica, Asia, Australia, Europe, North America, and South America.
Antarctica is the only continent not settled by humans.
The Ural Mountains of Russia are considered the dividing line between Europe and Asia. Europe and Asia form a landmass called Eurasia.
Earth is mostly a water planet, and 97% of that is found in the four oceans: Arctic, Atlantic, Indian, and Pacific. Ocean water is salty and cannot be used for drinking or farming. Under 1% of Earth's water is fresh water.
In California, the Pacific Plate is slowly grinding past the North American Plate.
This creates pressure along the San Andreas Fault, which causes earthquakes.
(Tip #486: Don't live where the earth is moving.)