Geothermal Energy Heat on Earth 97 of all

Geothermal Energy

Heat on Earth • 97% of all energy on Earth comes from the Sun • 3% comes from Earth’s interior

Earth’s Internal Heat • Heat of Formation: 50% is the heat left over from the formation of Earth • Radiogenic Heat: 50% comes from the radioactive decay of rocks • Earth’s internal heat drives plate tectonics

Earth’s Core • The outer core creates the magnetic field • The magnetic field protects Earth from solar winds and gamma radiation

Earth’s Core • The inner core is hotter than the surface of the Sun • The inner core is slowly cooling down, solidifying and getting larger

Radioactive Decay • Elements decaying in Earth’s core generate heat • Radioactive decay of elements help scientists age the oldest rocks on Earth • Radioactive Isotope: an unstable element that decays into a different element • Uranium • Thorium

Radioactive Decay • Half-life: The time it takes for ½ of an element to decay into another element • Uranium (92) decays into lead (82) and all the energy released is radiation • Uranium has a half life of 4. 5 billion years

Geothermal Energy • Geothermal Energy: heat that is stored inside of the Earth • Can be harnessed to heat our home and buildings • Renewable energy source: one that is constantly being made

Geothermal Energy • Geothermal energy: • Creates Geysers • Creates plate tectonic motion • Creates Electricity: use steam to turn a turbine • Is Clean: does not release pollution into the atmosphere