Heat radiation is invisible to the human eye
but the radiation from hot bodies can be felt by your hand. The
proper name for heat radiation is INFRA RED RADIATION.
All objects emit heat radiation. If we take two objects of the
same material and the same size but at different temperatures the one which is hotter will
emit more radiation.
Two objects of the same material and the same temperature but of
different sizes emit different amounts of heat radiation – the bigger one emitting more
radiation than the smaller one.
Heat radiation experiments show that: