What is rust? Why does metal rust?
“Rust is the result of a conversion process that takes place when oxygen and moisture come in contact with metal (oxidation). The oxygen and water combine with iron to create a brown coating (hydrated ferric oxide) on the surface of the metal. The interaction between the water and iron is accelerated if salts are added to the mix. If allowed to continue, the iron metal will be completely converted to ferric oxide or solid rust, which is weak and flaky.” (from Rust Doctor website)
You read through it and you are still not sure what rust is. But it has provided you with some more clues. Rust has something to do with metal and water. The chemical term they use is “oxidation” of the metal with the air and water. Oxidation is a gain of electrons. You will learn more about this later. You don’t have to fully understand something to “kind of get the idea.”
Now you might have enough information to create an experiment. We still do not know what metal they are talking about. There is iron, nickel, copper, steel, and many other kinds of metal on the market. Do all of them rust?
How can you design an experiment? In order to experiment with rust you will need metal, water, air, and time. First, make a list of possible materials you would need. In determining if all metals rust, it would require that we expose metals to water and oxygen. We could use a test tube and put in a little metal and squirt some water on it and see what happens. Will salt increase or decrease the reaction? The following worksheet shows you a design of an experiment that might help determine how rust reacts. Underline the areas where math is involved. You may want to try the experiment to see if it works or you may want to design a better experiment.