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Energy Transfer

Heat - Radiation.

Infra-red radiation transfers heat between all objects.
Infra-red radiation is an electromagnetic wave
 and can travel through a vacuum.
Heat from the Sun reaches us through the vacuum of space
by travelling as infra-red radiation.

An object can absorb (take in), emit (give out) and reflect radiation.

A hot object will emit more infra-red radiation than it absorbs.
A cold object will absorb more infra-red radiation than it emits.
In this way heat is transferred from hotter to colder objects.
An object whose temperature does not change
will emit infra-red radiation at the same rate as it is absorbed.

Objects which are at the same temperature as each other
will absorb, emit and reflect infra-red radiation at different rates
depending on the type of surface which the object has.

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Copyright © 2008 Dr. Colin France. All Rights Reserved.