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Making use of energy – WJECRadiation

Heat energy can be transferred from areas of high energy to areas of lower energy by conduction, convection and radiation. Understanding how to control these processes helps reduce energy consumption.

Part of Physics (Single Science)Electricity, energy and waves

Radiation

Heat transfer by radiation

Heat can be transferred by radiation. Unlike and - which need particles - infrared radiation is a type of electromagnetic radiation that involves waves.

The sun peeking over the horizon of Earth from space
Image caption,
Light from the Sun reaching Earth

Because no particles are involved, radiation can even work through the of space. This is why we can still feel the heat of the Sun even though it is 150 million kilometres from the Earth.

Different surfaces

Some surfaces are better than others at reflecting and absorbing infrared radiation. This table summarises some differences.

SurfaceAbsorptionEmission
Dull, matt or rough, dark colouredGoodGood
Shiny, light colouredPoorPoor
SurfaceDull, matt or rough, dark coloured
AbsorptionGood
EmissionGood
SurfaceShiny, light coloured
AbsorptionPoor
EmissionPoor