ABSTRACT
Approximately 4,000 miles below the Earth’s surface is the core, where temperatures can reach 9000º F. This heat—geothermal energy (geo, meaning earth, and thermos, meaning heat)—flows outward from the core, heating the surrounding area, which can form underground reservoirs of hot water and steam. These reservoirs can be tapped for a variety of uses, such as to generate electricity or heat buildings.
