Polymerization

Polymerization is a process where short, simple molecules stick together to make a long chain. It usually happens when you mix small molecules together with special glue, or a catalyst. The small molecules are called monomers, and when they join together to make a long chain, it's called a polymer. An example of a polymer is plastic: the monomers are things like ethylene, which join together to make a long chain that looks like a plastic.