Acids and Bases

Here’s a really simple Science lesson that you can put together in an evening for a couple of euro – handy for those nights that you’re scrambling for something to do!


  • 5 containers and 5 copper (1c, 2c or 5c) coins per group.
  • Tomato Ketchup
  • Vinegar
  • Lemon Juice
  • Bottle of Coke
  • Water

Image result for tomato ketchup coke and vinegar


  1. Explain that the children will be investigating the best coin cleaner.
  2. Have each group predict which one they think will work best.
  3. Decide how to conduct a fair test – (same amount of each substance used, same amount of time, coins in similar condition before test).
  4. Leave coins to sit for twenty/thirty minutes (you could teach a quick lesson on acids/bases and the pH scale here).
  5. Examine coins and note best cleaner (it should be the tomato sauce as it is the best acidic, which counteracts the base, copper oxide, on the coins).

This is such a simple little experiment, but the kids loving sticking their hands in a bowl of ketchup or Coke, and you can explicitly teach the scientific method through hypothesising, designing a fair test, and writing down the materials and procedure as above!

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