BSL Physics Glossary - geothermal - definition
Definition: Geothermal energy is warmth from the centre of the earth. In the centre of the earth it is really hot, so hot that it is a liquid. The earth has got a hard crust on the surface. Steam and gases from the centre of the earth pass up to the surface, making the surrounding rocks hot. Sometimes the geothermal energy gets right to the surface and makes the surrounding area warm.