Page 31 - Curriculum Visions Dynamic Book

Aluminium is a poor “radiator”
One of the special features of aluminium is that it is very poor at radiating heat. This means that, for example, if the sun shines on a piece of aluminium, any heat energy not reflected will cause the aluminium to heat up, but very little of the heat will be radiated.
Aluminium shares its heat by conduction or by heating the surrounding air, so that heat is lost by convection.
This means that a sheet of aluminium used to protect an object from the Sun will be much more effective than a sheet of steel. The aluminium will absorb the heat whereas the steel would absorb the heat on one side and radiate it from the other.
conduction: (i) the exchange of heat (heat conduction) by contact with another object or (ii) allowing the flow of electrons (electrical conduction).
convection: the exchange of heat energy with the surroundings produced by the flow of a fluid due to being heated or cooled.
radiation: the exchange of energy with the surroundings through the transmission of waves or particles of energy. Radiation is a form of energy transfer that can happen through space; no intervening medium is required (as would
be the case for conduction and convection).
 Aluminium is often used instead of silver on large mirrors. It has good reflective properties, but is far less expensive than silver. The mirrors shown here are part of a solar generating plant.
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