Shining Pennies
Introduction:
After being passed from person to person, hand to hand, it is no surprise that pennies can get quite dirty. If you’ve ever seen a brand new penny, it is a shiny copper color, but they will eventually turn brown. This is because of dirt and grime, but also because of copper oxide.
Copper oxide forms when the oxygen in the air around us binds to the copper in a penny. The reaction is called oxidation, and it produces dark spots, eventually covering the whole penny overtime. Many metals found in everyday objects will oxidize, such as steel, iron, nickel, and aluminum. Old nails left around turn a reddish brown because the steel it is made out of has oxidized. Even the Statue of Liberty’s greenish color is due to oxidation of the copper, brass, and other metals it is made out of. We normally call the oxides that form on metal “rust.”
However, we can also remove the rust using some materials that you might already have in your pantry: vinegar and salt!
Materials:
Dirty pennies
Cup
Vinegar
Salt
Spoon
Paper towels