Science4MyKid
Science Project: Bright as a Penny Viewed: 6550
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Bright as a Penny

Soap and water won't clean metals very easily. That takes a special cleaner - or you can try lemon juice or vinegar (white works best)!

You need:

  • 1 oz. lemon juice or vinegar (30 ml)
  • a dull penny or other copper coin
  • a small glass or paper cup

What to do:

Soak the coin in lemon juice or vinegar for 5 minutes.

What happens:

You fish out a shiny coin!

Why:

Oxygen in the air combined with the copper to form the dull copper oxide coating. The acid of the lemon (or vinegar) acts chemically to remove the oxide, and the result? A bright copper penny.

Be careful not to get the lemon juice or vinegar in your eyes, it will burn