The process of rusting is when you leave a metal to face the elements, mainly water and wind. This causes rust which is the process of a metal going old and eaten away by a substance called rust or iron oxide. To create rust you need water and air these mix to cause the metal to be eaten away by rust. Rust is a reddish brownish colour and there are some metals that don’t rust like stainless steel. Iron oxide breaks the bonds between the metal and replace them with rust. It might take a long time but some metals will rust.