Lesson Of The Week: Rust

Did you ever wonder why metal rusts? Well, the short answer is water. Here's how it works. Metals are very strong materials; however, many metals are susceptible to oxidation. Rust is the result of the oxidation of metal. Oxidation is when the molecules of metals combine with oxygen molecules.

Even though metals seem to have no weak spots, microscopically, they are very vulnerable. The easiest way for oxygen molecules to reach metal molecules is through water. You're probably asking "what about air?" Well, oxygen in air is stable, so those oxygen molecules are not looking to bond with other molecules. However, when water molecules find microscopic spaces in metal, a reaction occurs. The hydrogen atoms bond with some of the elements in metals to form acids. This does two things. First, it frees up the oxygen molecules from their bond with hydrogen and they find a new partner in the metal, which is oxidation. Second, the acid compound form creates more areas of exposure on the metal. This is the reason why it is best to store metals in a dry environment.

Rust weakens the strength of metal. Solutions to this problem are usually either coating the metal with a waterproof liquid or using thicker metals. The thicker the metal, the more resistant they are to the effects of rust.