The interior of the earth is at a higher temperature than it would be if it were cooling steadily; there must be internal sources of heat. Current models of the earth’s interior suggest that one source of heat is the crystallization of liquid iron. Explain how this process provides heat to the earth’s interior.

The interior of the earth is at a higher temperature than it would be if it were cooling steadily; there must be internal sources of heat. Current models of the earth’s interior suggest that one source of heat is the crystallization of liquid iron. Explain how this process provides heat to the earth’s interior.