A plant in which a turbine is driven either from hot water or by natural steam that derives its energy from heat found in rocks or fluids at various depths beneath the surface of the earth. The fluids are extracted by drilling and/or pumping. The 350-degree steam from the Napa Valley _______, that rushes more than 1,500 feet up from the earth, spinning turbines which creates a constant flow of clean electricity.

Energy possessed by virtue of an object's motion The _______ a rocket gains during its launch will remain constant while in orbit because there is almost no friction.

The most common gas formed in coal mines; a major component of natural gas. The Earth's mantle contains huge amounts of _______ and is the main reservoir.

A system in which solar energy alone is used for the transfer of thermal energy. Pumps, blowers, or other heat transfer devices that use energy other than solar are not used. Buildings designed for _______ and daylighting incorporate design features such as large south-facing windows and building materials that absorb and slowly release the sun's heat.