Emitting Heat Radiation

Things which are hot emit heat radiation. If they are not actually producing heat then they will cool down.

This heat lamp is producing heat energy. It will keep emitting heat radiation till you turn it off.	This pizza will start to cool down as soon as it is taken out of the oven.

How quickly something emits heat radiation depends on how hot it is. It also depends on what kind of surface it has. Some surfaces emit more radiation than others.

If we want something to give off lots of heat paint it black. It you want it to stay warmer for longer then paint it white or silver. Here are some examples.

Cooling fins on a chip are black. This helps to stop the chip over-heating.	Most kettles are white or silver. The water will stay hotter for longer.	Look at the back of your fridge. It is black. The fridge takes heat from inside and sends it outside.	This injured person is kept warm with a silver blanket.