This visually striking lab clearly illustrates the processes of rusting, corrosion and cathode inhibition. Iron metal will rust in the presence of air and water, a process that accelerates in ocean water. Yet, in the presence of another metal (such as magnesium) the nails will not rust for a very long time as the magnesium sacrifices itself by supplying electrons to the iron nail. Eventually the magnesium will vanish, and a white solid will form on the bottom of the petri dish. Developed by Ray Steigvilas. Includes materials for five student groups and instructions. Grades 7–12.