Discovered a mere one hundred fifty

Discovered a mere one hundred fifty years ago and manufactured commercially just half that
long, aluminum today ranks behind only iron and steel among metals serving mankind. The key to its popularity is its incredible versatility. The same metal that makes kitchen foil serves as armor for battle field tanks. The material of lawn chairs and baseball bats also forms the vital parts of sir and space vehicles—most of their skeletons, their skins, even the rivets that bind them together. Behind aluminum’s versatility lie properties so diverse that they almost seem to belong to several different metals. For example, in its pure form, aluminum is soft enough to whittle. Yet its alloys can possess the strength of steel, with only a third of its weight. Thus, when Alexander Calder designed one of his last mobiles—a soaring creation eighty feet long— his choice of aluminum over steel cut two tons from its weight. Aluminum also assures the masterpiece virtual immortality. The instant the metal is exposed to sir, its surface acquires a transparent film that seals the interior against further corrosion.