Geothermal energy is formed within the Earth. Geothermal energy is clean and stable, but it's only available near tectonic plate boundaries. Plate boundaries are where volcanic activity and earthquakes occur. More »

www.reference.com Science Physics Thermodynamics

Geothermal energy works by using the heat created by the Earth and turning it into an energy source for people to use. This clean, renewable resource provides energy in the United States and around the world. More »

www.reference.com Science Earth Science Geology

While geothermal energy is very environmentally friendly and does not produce large quantities of pollution, only limited sites have the potential for energy generation and upfront costs are often considerable. Geotherma... More »

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Solar energy has been used by humans for 2,700 years. Originally, glass lenses were used to make fire with the sun's rays. According to the U.S. Energy Information Administration, the first recorded use of a solar therma... More »

www.reference.com Science Physics Thermodynamics

In the atmosphere, convection currents occur due to the heating of the Earth's surface by radiant energy from the sun. As the air near the ground warms, it becomes less dense and rises. Colder, dense air falls to the sur... More »

The sun is the primary source of radiant energy on Earth, according to Explorit Science Center. Radiant energy is a type of electromagnetic radiation. Upon leaving the sun, this energy reaches Earth - a distance of almos... More »

There is no one constant coldest thing on Earth, but a copper cube nearly reached coldest temperature possible. Using advanced technology, scientists managed to cool this copper cube to the lowest temperature ever record... More »