Old but Shiny??

In the olden Chinese New Year Tradition, red envelopes are given to children containing brand new money.
Now you can make old copper coins shiny and new with this science activity!

Instructions:

1. Ask your parents for a few Singapore 1 cent coins. (pennies from the United States of America works too!)
2. Combine 1/2 cup vinegar with 4 tablespoons salt. Stir until the salt dissolves.
3. Drop copper coins into mixture, wipe off with towel, rinse in water and dry. This will make them shine!

Alternatively, you may dip a toothbrush into the mixture to scrub the pennies, rinse in water and dry. This will make them shine too!

Science Bites:

Copper coins or pennies get dull over time because the copper slowly reacts with oxygen in the air to form copper oxide. Pure copper metal is bright and shiny, but the oxide is dull and greenish. When you place the copper coins or pennies in the salt and vinegar solution, the acetic acid from the vinegar dissolves the copper oxide, leaving behind shiny clean pennies. The copper from the copper oxide stays in the mixture of salt and vinegar. You could use other acids instead of vinegar, like lemon juice too!