CORROSIONS

 Corrosion happens when the atoms on the surface of an object undergo a chemical reaction with atoms from the environment. The chemical reaction produces new substances that change the material's colour or texture. These new substances might not bind to the material very tightly, so the material's surface might start to become rough or weak and is more easily worn away by wind or rairn.

Corrosions is a common problem with many metals. One of the metals that it affects most often is iron. When iron corrodes, it combines with water and oxygen molecules from the air to form a new substance cs redalled iron oxide, which is reddish-brown in colour. It is rust.