Cabbage Indicator

Best Ever Kitchen Science Experiment!

A science experiment you can do in your own home! Cabbage can be made into an indicator to test for acids and alkaline substances!

The Geeky Bit...

What is an indicator?

Indicators are substances that change colour when they are added to acidic or alkaline solutions. You're probably used to using universal indicator in science at school.

How does it work?

Red cabbage contains a pigment molecule that changes colour depending on the pH of a solution.

You will need:


To prepare the indicator, you will need:

  • Red Cabbage

  • Grater (a knife can be used if a grater isn't available)

  • Boiled water (from the kettle)

  • Sieve/strainer

  • Two containers (large glass or mixing bowl)

To prepare the indicator:

  1. Grate (or chop) the red cabbage into small pieces.

  2. Add the grated cabbage into one of the containers.

  3. Pour boiling water over the cabbage pieces until they are completely submerged.

  4. Leave to stand for 10 minutes. This will allow the water to cool and you will notice it has changed colour.

  5. Carefully sieve the mixture and collect the liquid in the second container.

To use the indicator:


To use the indicator, you will need:

  • Clear containers (e.g. small glasses or plastic cups)

  • Marker pen/labels/strips of paper and pen

  • Household substances (e.g. lemon juice, orange juice, vinegar, water, soap, toothpaste, mouth wash, baking soda, coca cola, tap water, laundry detergent, black coffee, milk of magnesia, shampoo, egg white).

To get your results:

  1. Add some of the cabbage indicator to each container (how much will depend on how much of the liquid you were able to separate from the cabbage).

  2. Label each container with the substance you are going to add to it.

  3. Add a small quantity of the substance to your cabbage water.

  4. The colour will change (you may need to stir with a clean spoon).

  5. Use the scale below to decide whether your substance is an acid or an alkali. Make a table of your results using the document below.

Cabbage Indicator Results

How to support your child:

Tells us about it!

You can help too! How?

  • Care should always be taken when using sharp objects, which is why a grater has been suggested here.

  • Supervise your child throughout.

  • When the finished, the substances can be rinsed down the sink with water.

  • Take care to not spill the cabbage water, particularly onto fabrics as it may stain.

  • In the event the cabbage water gets into the eyes, rinse with cold water.

  • The household substances suggested here are safe for children to use without gloves. Do not allow children to mix the different household substances together. Do not use bleach or oven cleaners - they are highly alkaline substances and are corrosive.

  • Indicators are best made and used on the same day or refrigerated and used the following day.

If you want to share your results, you can submit it using the form found in the navigation bar titled "Tell us about it." You can also tweet about your experiences, make sure you tag in @OGATrust and the twitter account for your academy as well!