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KS1 Science at Home: Week 3

An experiment for you to try at home.....

Key Stage 1 Experiment of the week – 'Polishing Pennies!'

How does it work?

Pennies are made out of a metal called copper. The copper mixes with oxygen, the same gas that we breathe. This cause something called ‘oxidation’ and makes the penny look dirty. Lemon juice has acid in it that removes the dirty colour or oxidation and makes the penny nice and shiny again!

Shiny Penny     Polishing pennies

Materials you need

  • Lemon Juice
  • Dirty Pennies
  • A cup
  • Paper Towels
  • Taco Sauce (optional)


  1. Put a dirty penny in the cup and cover it with lemon juice.
  1. Wait about five minutes then remove the penny and wipe it off with a paper towel.
  1. Try the taco sauce to see which works better.

Questions to think about

1. Does vinegar work?

2. If you colour the penny with marker does it come off?

3. Does it work with pound coins or silver coins?

Some Research for next week: What does 'absorption' mean? 
We will answer this question with next week’s science experiment!