Corrosion of metals
Metals tend to be eaten away slowly by chemical reactions. They corrode. Corrosion is a big problem in all our lives. Building materials, fasteners, tools, utensils, car bodies and many other metal things are all slowly disappearing. Metals corrode because they combine with oxygen in the air. If people made no attempt to stop corrosion we would not be able to afford to replace the metal which is disappearing back into the earth.
Iron + Oxygen –> Iron Oxide
