Chemistry cleans
pennies...
We need chemistry for lots of things - medicine, computers and
cars. How about using chemistry to clean your pocket money? What do
you think of when you hear "salt and vinegar"? Crisps? Chips? You
can use salt and vinegar to clean your pennies!
What you need:
- Dirty pennies
- White vinegar
- Table salt
- Shallow glass or plastic bowl
How to:
- Put a couple of your dull, dirty pennies in the bowl.
- Cover the pennies with salt.
- Pour white vinegar over the pennies.
- Rub the salt and vinegar mix over both sides of the
pennies.
- Take the pennies out and wash off the salt and vinegar
mix.
What do you see? The pennies should be much shinier.
This video shows you what to do:
How does it work?
Pennies get dull and dirty because the copper in the pennies
reacts with oxygen in the air to form copper oxide. When you put
your pennies in a vinegar and salt mix, the vinegar and salt react
together and remove the copper oxide.
What happens if you don't wash the pennies once you've taken
them out of the salt and vinegar mix?
Try it and see!
Have you tried it yet? Leave the pennies on a paper towel and
wait for about an hour. The answer is below the picture.
If you don't wash the salt and vinegar mix off, a blue-green
layer forms on the pennies. The salt and vinegar mix speeds up the
reaction between copper and oxygen in the air, forming copper oxide
- which is a blue-green colour. It's the same reaction that makes
the Statue of Liberty green!