Science Experiment – Acid Test

By AG Education 4 September 2017
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Do you know what acids are hiding in your kitchen?

Acid Test

By mixing together ordinary items from the kitchen, you can change the colour of liquids in a flash!  Almost all liquids are acids or bases to some degree – an acid is a liquid with a lot of hydrogen ions, and a base is liquid with lots of hydroxide ions. Chemists use strong acids and bases to produce chemical reactions in the lab, and we also use acids in car batteries, cleaning products and fertiliser. This experiment tests whether certain household liquids are acidic, alkaline (a base liquid), or neutral. Make sure you ask a parent to help!


  • A clear mixing bowl, ideally glass
  • 7 clear plastic drinking cups
  • Red cabbage
  • Kitchen knife
  • At least 30ml of each of these liquids
    – Lemon juice
    – Vinegar
    – Bicarbonate of soda
    – Washing-up liquid
    – Tomato sauce
    – Lemonade
    – Tap water


  1. Carefully chop the cabbage and put small pieces into the bowl with 250ml of water from the tap, then mash it with a fork until the water turns bright purple. Pour 20-30ml of the purple liquid into each plastic cup.
  2. Now add 20-30ml of your 7 liquids to the cups individually, making a note of which liquid has been added where. Write down what happens to each cup.

When the cabbage juice turns red, it means your mixed is acidic. If the juice turns blue, the mixer is an alkaline base. If it doesn’t change at all – it’s neutral, near the middle of the acidic scale!

Do you want to keep learning? Find more experiments here!