The theory of plate tectonics was developed in the 1960s to help explain the earth’s internal processes, plate movements and landforms rising from these movements. This theory explains the origin of most of the major physical features of the earth’s surface. According to it, the earth’s surface is an outer shell made up of about 30 rigid pieces called plates. These plates are like the cracked pieces of an eggshell. Some of the plates are gigantic whilst others are small.
The plates move about on a layer of very hot liquid rock. They move very slowly relative to one another, at speeds of about 10 centimeters per year. Over the past several hundred years, the movement of plates has changed the outlook of our map of the earth.
This page was created by Tharani Anandarajan for the Thinkquest Internet Challenge 2000.