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National Chemistry Week - Experiments - Green Pennies
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The Aim:
to demonstrate a chemical change using pennies and vinegar
What you will need:
- saucer
- paper towel section
- vinegar
- 3-5 pennies
What to do:
Fold the paper towel to form a square.
Place this paper towel in the saucer.
Pour enough vinegar into the saucer to cover the paper
towel.
Place the pennies on top of the wet paper towel and
hours.
Encourage observations; look at both sides of the
pennies.
![[IMAGE OF PENNIES ON A PLATE]](../experiments/images/pennies.gif)
The tops of the pennies turn green and the bottoms of the
pennies stay copper coloured. Vinegar is an acid that has the
chemical name of acetic acid. Part of this acid combines with the
copper of the pennies to form a green coating that is composed of
copper acetate. Oxygen must be present for this chemical reaction
to occur. Oxygen comes from the air, and this is why the tops of
the coins turn green but the bottoms do not.
To see other chemical changes that occur due to an acid see The Disappearing Egg Shell,
Bones in Knots and
The Erupting Volcano.
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