Aluminum is the most abundant of all the metals. As well, it is the third most abundant element on the earth’s surface (oxygen and silicon being more common). Because aluminum is a rather reactive metal, it is not found in nature in the free state. However, its compounds are very common. It occurs as aluminum oxide in the minerals corundum and bauxite, and as many complex aluminosilicates such as beryl.Although pure aluminum is a rather soft and weak metal, it has several hard, strong alloys. (Alloys are solids which have metallic properties and are usually composed of two or more metals. For many practical purposes, alloys are often more useful than pure metals.) Because these aluminum alloys have a low density and are not subject to corrosion, and because the metal surface is protected by a thin hard unreactive film of aluminum oxide, they have many important uses. For example, they are used in aircraft and space vehicles, garden furniture, door and window frames, and kitchen utensils. Billions of beer and soft drink cans are manufactured each year from aluminum. In the form of foil, it is used as wrapping material.
Other applications of aluminum are based on the fact that it is an excellent conductor of electricity. Although a wire of aluminum has only one-third the conductivity of a copper wire of the same diameter, the aluminum wire is much lighter because of the low density of aluminum. Since it is also considerably cheaper than copper, for a time aluminum has been used for electric wiring. However, safety issues caused it to fall out of favour in domestic use.
Although aluminum products are common today, this has not always been the case. It wasn’t until 1885 that a young man named Charles Martin Hall discovered the process to make aluminum. He did so in his woodshed by passing an electric current through a heated cryolite-alumina mixture. This discovery made Hall a rich man.