In this activity, learners conduct an oxidation experiment that turns old pennies bright and shiny. Learners soak 20 dull, dirty pennies in a bowl of salt and vinegar for five minutes. They rinse half the pennies with water, then compare the rinsed pennies to the unrinsed after all pennies sit and dry for about an hour. Learners also observe what happens when they submerge a screw and nail in the liquid compared to a nail only half-way submerged.