by Miruna and Beatrice
Materials you will need: paper towel , lemon, knife, plastic cup or bowl, dirty/old copper coins
Cut the lemon ans fill the cup/bowl with some lemon juice. Put the dirty copper coins in the juice and let them soak for a few minutes. Remove the coins from the cup/bowl and place on the paper towel..
Oxygen in the air reacts with copper, making a copper oxide coating. This is what makes copper coins dirty. The acid in the lemon juice reacts with the oxide and removes it from the coins – making then shiny copper coin.