Theory Thursday: Shiny Pennies

We've been doing a lot of money counting lately (and it's not because we got our taxes back.) We've practiced with fake coins, M&M's, chocolate coins, and real money. I even had them help me separate and roll coins. (Ok, that was more for me than them, but they don't know that!)  Jake knows how to count pennies and dimes well and is getting pretty good at nickels. This week's experiment coincided well.  

Supplies:                                        
A few old, dingy pennies                Non-metal bowl
1/4 cup white vinegar                     Paper towels  
1 teaspoon salt                               2 cute helpers (optional)             

Directions:
1. Pour the vinegar into the bowl, add the salt, and stir.
2. Put the pennies into the bowl and count to 10 slowly.
3. Take out the pennies and rinse them in water.

Gather your supplies.

Add vinegar and salt.

Stir.

Drop in the pennies.

Slowly count to ten. Then rinse with water.

Admire their shininess!

Chemistry is at work here. Since vinegar is an acid and reacts with salt, it removes the dulling copper oxide, leaving the penny shiny again.

Repeat the process without rinsing with water.

The penny will turn greenish blue as malachite forms.

Leighton explained to Jake and Alyssa that this is the reason the Statue of Liberty is green. Jake thought it was pretty cool and proceeded. to recite the Pledge of Allegiance for us. He was even more impressed though that the "vinegar smelled like ketchup." Oh, and that they got to keep the pennies in the end.