This is a picture of the Earth as it looks today:
This is how scientists think it looked over 200 million years ago:
A single continent called Pangaea
The continents are moving away from each other.
Scientists call the movement of the continents continental drift. The picture below shows the directions the continents are slowly moving, perhaps only two inches a year. That's about the speed that your fingernails are growing right now. You can't see or feel it.
The continents aren't floating on the oceans. Continents are part of the Earth's crust, the top layer of the Earth, made of solid rock. The oceans are above the crust. The crust and the oceans are floating on a layer of the Earth that is so hot it is almost melting. This section of the Earth is called the Asthenosphere. The crust of the Earth is separated in several huge sections or plates which float on the Asthenosphere at various speeds and directions. Plate Tectonics refers to the changing of Earth through the movement of huge sections of the Earth's crust.
