What are tectonic plates?
The Earth's crust and upper part of the mantle is cracked into massive pieces called tectonic plates, which move a few centimetres a year because of convection currents in the mantle - caused by energy released from the decay of radioactive elements heating up the mantle.
What happens when the plates meet?
Huge forces build up causing rocks to give way, changing shape or moving suddenly causing earthquakes, volcanoes or mountains to form. Scientists still do not know enough about what is happening inside the Earth to predict exactly when and where earthquakes or volcanic eruptions will happen.