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Try wikipedia.org also
From Wikipedia, article Aluminum Foil:
Aluminum foil (Aluminium foil in Commonwealth English) is aluminum prepared in thin sheets (on the order of 0.02 mm in thickness). As a result of this, the foil is extremely pliable, and can be bent or wrapped around objects with ease. Aluminum foil is sometimes known as al-foil or alu-foil. It is also often called tinfoil, although it is not made from tin; or in North America, as Reynolds wrap after Reynolds Metals Company, the leading manufacturer when it was introduced on the American market (Much to the chagrin of Alcoa, Reynolds main competitor, which had its brand "Alcoa Wrap" referred to as "Alcoa Reynold's Wrap").
Aluminum foil typically has a highly reflective side and a more matte side. This is a result of common manufacturing processes. As aluminum foil is easy to tear, the foil is sent through machines in pairs. The side where the aluminum foil was in contact with the other sheet is more matte than the exterior side.