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Energy Transfer

Heat - Radiation - Surfaces - Absorption and Emission.

An object with a matt (dull) surface will absorb and emit
infra-red radiation at a faster rate than an object with a shiny surface.
An object with a dark surface will absorb and emit
infra-red radiation
at a faster rate than an object with a light surface.
Radiation is also reflected at the surface.

Imagine a hot piece of metal which has a matt black surface
and a shiny white surface.
A thermometer is placed at the same distance from both surfaces.
Heat Radiation from a Matt Black and Shiny White Surface

The thermometer next to the matt black surface
shows a higher temperature because it emits radiation at a faster rate.
Heat leaves the metal more quickly through the matt black surface
than the shiny white surface.

Part of the space shuttle is covered in matt black tiles.
These help the craft to lose heat from its surface
when it re-enters the Earth's atmosphere on returning from space.
The space shuttle gets very hot in the Earth's atmosphere
in the same way that meteors do.

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