Rusting

Rusting occurs when iron is exposed to oxygen and water for a period of time. The metal is usually covered in a red/brown coating. Rusting in a way is the gradual decaying of a metal. Not all metals rust. Metals that rust easily are iron and steel.

Aluminium, gold and platinum are also examples of metals that don't rust easily.

NB: When iron comes into contact with oxygen and water, it rusts.