Tectonic plates move due to convection currents in the mantle.
Heat from the core makes magma in the mantle rise towards the crust. As the hot current nears the crust, it begins to cool and sink back towards the core.
As the magma sinks, it drags the plates across the surface of the Earth.
The movement of the plates, and the activity inside the Earth, is called plate tectonics.
The point where two plates meet is called a plate boundary.
