-conduction is the transfer of heat energy without the substance itself moving.
strucutre of metals makes them a good conductor of heat.
metal gets hotter the particals gain more kinetic energy and vibrate.
transfer of heat energy thorugh movement.
occurs in liquids and gases and creates convection currents
thermal, or infra red, radiation is the transfer of heat energy by electromagnetic waves ; no particles of matter are involved.
all objects emit and absorb radiation.
hotter objects more engery it radiates.
heat transfer can be slowed down by the use of insulation which provides a barrier.
dark matt- emit more radiation. dark matt- absorb more radiation that light
conduction- through the walls,floor and windows.
convection- convection currents coupled with cold draughts from gaps in doors and windows cause heat energy to rise up to the roof space where it is lost
radiation-through the walls, roof and windows
transferring and transforming energy
when devices transfer energy, only part of the engery is usefully transferred to where its wanted in the form its wanted.
remaining energy transfromed in a non useful way. (waste engery)
EFFICIENCY=useful energy transferred by device/total energy supplied to device