How Does Salt Water Rust Metals?
Rust is essentially oxidation, or a chemical interaction involving oxygen. When oxidation occurs in some elements, a thin film is formed as a result–such as the green layer that copper acquires. Other elements, such as iron, show rust as evidence of oxidation. If iron–or metal related to iron–is exposed to an environment both oxygen-rich and friendly toward the catalyst, then the oxidation process will begin. Molecules of iron at the surface of the iron object will exchange atoms with the oxygen in the air, and what atoms are left will form a new substance, the reddish-brown rust. Air is not always necessary to cause rust, only the presence of oxygen, and oxygen can be found in water as well as air. In fact, water is usually considered the third part of the oxidation process, since it allows the oxygen and the iron to meet. This is why areas with lots of moisture in the air, with the presence of water vapor, have much faster rust rates than dry areas. To look at it another way, oxid
