Heat Controlling Heat
Thermal Conduction Thermal conduction – the process by which energy is transferred as heat through a material between two points at different temperatures Particles start vibrating and moving, causing collisions Energy is transferred through collisions Thermal conductors – transfer energy as heat rapidly Most metals Thermal insulators – transfer energy as heat slowly Asbestos, cork, ceramic, cardboard, fiberglass, plastic, rubber, gases Cooking oil is not a good conductor, but it is used to transfer energy evenly
Convection and Radiation Convection – transfer of energy using the displacement of cold matter by hot matter Hot air rises, cold air sinks Radiation – energy transferred as waves Does not involve the movement of matter Sun, microwave ovens
Clothing and Climate Clothing is used to maintain body temperature Keep heat in in cold weather Cool the body off in hot weather Trap cool air close to the body or evaporate sweat to cool the body Dress in layers Traps layers of air between layers of clothes and the body Air is a poor conductor, so energy is not transferred