When studying plate-tectonics the best starting point is examining the structure of the earth. The earth is very similar to a peach in its structure. In the centre is a solid core. Surrounding the core is the inner core, then the mantle, which is covered in the earths 'skin' or crust.
In 1912 Alfred Wegener published a theory to explain why the Earth looked like a huge jigsaw. He believed the continents were once joined forming a supercontinent he called Pangaea. Over 180 million years ago this supercontinent began to "break up" due to continental drift. During the 20th Century, scientists developed the theory of Plate Tectonics. The theory suggested that the crust of the Earth is split up into seven large plates (see map below) and a few smaller ones, all of which are able to slowly move around on the Earth's surface. They float on the semi-molten mantle rocks, and are moved around by convection currents within the very hot rocks. The are two types of tectonic plates - continental plates and oceanic plates.
The point where two or more plates meet is known as a plate boundary. There are four main types of plate boundary. These are constructive, destructive, conservative and collision margins.
