Just one problem: it rusts. Enter stainless steel.
Stainless steel is a metal alloy with about 10-11% chromium. When exposed to air, the chromium in the metal forms a film of chromium oxide over the surface. This film is passive and non-toxic, and most importantly, it prevents the steel from rusting by shielding it from air and moisture. Even if the metal gets scratched, the chromium oxide reforms seamlessly.
This gives us all the excellent properties of stainless steel without the worry of rust. It's also non-reactive, unlike aluminum and iron, so we can use it for preparing and cooking acidic foods.
Simply put, we use stainless steel in the kitchen because it's one of the most durable, versatile, and worry-free metals available. It's hard to argue with that!
• For More Information: Stainless Steel on Wikipedia
(Images: Emma Christensen)