Explain how convection currents in the mantle drive the movement of tectonic plates.

Heat is produced through the radioactive decay of elements in the inner core. This heats the lower mantle, causing the magma to become less dense and rise. Once it reaches the upper mantle it cools, becomes more dense and sinks. This process repeats forming convection currents throughout the mantle which are strong enough to drive plate movement of a few centimeters per year.