A Magical Way to Discover the World of Science

Materials:
* 3 paper cups
* salt
* lemon juice or vinegar
* water
* dish soap
* dirty pennies
* paper towels

Directions:

1. Pour some water and a little dish soap into one cup.

2. Pour some lemon juice or vinegar in second cup.

3. Pour some pop into the third cup.

4. Add a few pennies to each cup and swirl for 30 seconds.

5. Look at the pennies.

6. Add 1 tablespoon of salt to the lemon juice/vinegar and add the pennies – swirl the cup and then remove the pennies.


What happens:

The pennies in the soap and water will not be bright and shiny. The pennies in the lemon juice/vinegar will not become super bright.  However, the pennies in the salt and lemon juice/vinegar solution will look like new!

Why:
Pennies become dirty/tarnished because of a chemical reaction that occurs between the copper/metal and the components in air – when an acid is mixed with salt it is able to create a chemical reaction that pushes the dirt and tarnish off of the penny