Transfer of thermal energy

Learning objectives

Describe experiments to compare good and bad thermal conductors, and at Extended explain conduction in terms of lattice vibrations in all solids and the movement of free electrons in metals

Explain convection in liquids and gases in terms of density changes, with supporting experiments, and at Extended explain why most liquids and gases are poor thermal conductors

Know that thermal radiation is infrared radiation that needs no medium, describe how surface colour and texture affect the emission, absorption and reflection of infrared and, at Extended, describe experiments to compare emitters and absorbers

Explain that an object stays at constant temperature when it emits energy at the same rate as it absorbs it, relate this to the Earth's temperature balance, and know that the rate of emission rises with surface temperature and surface area (Extended)

Explain everyday applications of conduction, convection and radiation such as kitchen pans and heating a room, and at Extended more complex cases such as a fire burning wood or coal, a car radiator and a vacuum flask, where more than one mechanism is significant