Stop the World, I Want to Get Off

Earth's surface consists of a hard shell called the crust, which is broken into large chunks called plates. Plates can hold entire continents (as the North American Plate does) or entire oceans (as the Pacific Plate does). Often, they hold bits of both.

The crust is actually a hard exterior on top of a much deeper layer, the mantle. Most of the mantle is made of thick liquid rock called magma, melted by heat from an even deeper layer--the Earth's core. The plates that make up the crust basically "float" on the mantle's magma.

That means the plates and everything on them, including whole continents and oceans, are in continual motion. Their movement is slow, ranging from less than an inch a year to a top speed of about 6 inches (15 cm) a year, but it's real. Just what drives the movement isn't clear. It could be gravity. It could be convection currents within the mantle. It could be both.


Want to learn more?
See what happens when you move tectonic plates


See what you're missing . . .
Become a lifetime member of
KnowledgeNews today!