Absorbers and emitters of thermal radiation
Some materials emit (give off) thermal radiation better than others.
Good emitters of radiation are normally also good absorbers of radiation.
Objects that are dark or rough are good emitters and absorbers of radiation.
Objects that are shiny, smooth or white are poor emitters and absorbers of radiation.
A black car and a white car are parked next to each other in the sun. The black car will be hotter than the white car as it is a better absorber of radiation.
Objects that have greater surface area transfer energy faster.
A larger radiator is able to heat up a room faster than a smaller one even if they are both at the same temperature.