Mechanisms of Heat Transfer

Evaporation

Conversion of a liquid to a vapor i.e. as water is evaporated from the surface of the skin, heat is removed.

Conduction

Direct transfer of heat through physical contact. i.e. you lose heat from skin to chair when you sit down on cold chair

Radiation

Transfer of heat as infrared rays from a warmer object to a cooler object without physical contact. i.e. when you feel heat wile sunbathing

Convection

Transfer of heat by the movement of a liquid or gas (fluids) between areas of different temperature. i.e. as your body conducts heat to the air next to your skin, the air wamrs, & rises, moving away from the skin.