Which heat transfer method describes heat from the sun?

• A. Metabolism
• B. Conduction
• C. Radiation
• D. Evaporation

Answer: (C)

Heat transfer from the sun occurs by radiation. Radiation is the transfer of heat through electromagnetic waves that can travel through empty space, so sunlight doesn’t need air or direct contact to warm something. The sun emits energy as visible and infrared radiation, and when those waves are absorbed by skin, earth, or other surfaces, they heat up.

This differs from conduction, which requires physical contact between objects and a medium to move thermal energy, or evaporation, which involves a liquid changing to vapor and carries heat away or into the surroundings during the process. Metabolism involves heat produced inside an organism and isn’t a way heat travels from an external source. Because sunlight reaches us through space without a medium, radiation is the correct mechanism.