Page 30 - Curriculum Visions Dynamic Book

Aluminium as a reflector
One of the most useful features of aluminium is its excellent reflective properties.
Aluminium reflects about nine-tenths of heat reaching it. This means it can be used to reflect heat back inside a room or container to help keep it warm, or it can be used to reflect heat away from a container to keep it cool. For this reason aluminium is often used as part of the insulation of a house.
The reflective properties of aluminium
can also be used in a quite different way.
If an aircraft wants to jam the radar of an incoming missile, it can release large amounts of aluminium flakes or strips. These reflect the radar signals of the missile and makes
it impossible to detect the correct target.
Aluminium and reflection in space
Aluminium is an excellent material to use in spacecraft and even in life support systems. This is because it is light, strong and has many useful heat reflecting properties.
The space environment is very harsh. People in space suits can be overheated while they are directly in sunlight, but they can begin to freeze when they are in the shade.
Aluminium helps to prevent the extremes of heat gain and loss
by reflecting the radiated heat away from the space suit and also reflecting the body heat back in. This keeps down the amount of heating or cooling equipment that has to be fitted on to the space suit.
 Space suits make extensive use of aluminium.
 Aluminium is increasingly used to conserve energy both in home heating and cooling and in the transportation industry. Aluminium storm doors and windows, insulation backed with aluminium foil, and aluminium siding are excellent insulators.
30
30