Transform a dirty penny into a shiny one. You'll see chemical changes right before your eyes!

Materials:

• Dull and dirty pennies
• 1/4 cup white vinegar
• 1 teaspoon salt
• Clear shallow bowl (not metal)
• Paper towels

Directions:

In a bowl, add 1 teaspoon salt to 1/4 cup white vinegar. Stir until the salt dissolves. Drop a few dirty pennies in the liquid and watch them become shiny. Rinse the pennies well under running water. Set them on a paper towel to dry.

Why Do the Pennies Change from Dull to Shiny?

The copper in the penny mixes with oxygen in the air and makes the copper dull in color. In the acidic vinegar solution, the copper separates from the oxygen, restoring its shine. (A nickel won't have the same reaction because it doesn't have copper, the element that causes this chemical reaction to take place.)

While children may not be able to understand much about the scientific explanation, experiments like this help children see that changes in science are predictable. They come about through cause-and-effect relationships. Children feel more secure knowing that transformations in the world are not just magic.

Talk with your child about how different the pennies look different after they've been in the vinegar solution. Talk about the fact that it is still the same penny, even though it may look very different now.

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