If you ride a bike, you might have noticed how important it is to not leave your bike outside, especially in the rain. If you do, parts of your bike will begin to rust. When enough rust has built up on the moving parts of the bike (like the chain or wheels), it can make it very difficult to pedal. Rust is a brownish-orange substance that you can find on certain types of metal objects. 

Rust is a substance that forms from a chemical reaction with iron and oxygen. Any iron object that is exposed to oxygen might rust over time. When an iron object turns to rust, the rusted object is weaker and more brittle than the iron it used to be made of. But it is rare to find a pure iron object these days. Iron is typically used to make things like tools, cooking equipment, weapons, and farming machinery. Steel, however, is also used to make lots of objects, and steel is made of mostly pure iron atoms, with a small amount (around 5% or less) of carbon atoms in it. Since steel is mostly made of iron atoms, it rusts too! Think of all the steel objects you have seen outside that you have found rust on. 

In this investigation you will be use NetLogo models to simulate and visualize the molecules involved in this chemical reaction.