Church of England School of the Resurrection

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Science at Home!

Looking for some experiments you can do at home with every day items? Look no further!

 

DIY Red Cabbage pH Indicator

Want to check if something is an acid or an alkali? Make your own indicator.

You will need:

Red cabbage
Water
Anything you want to test.

  1. Firstly, chop up the red cabbage into small pieces. Place it into a saucepan and cover the red cabbage with water.
  2. Bring the solution to a boil and then turn off the heat. Let it sit for about 30 minutes to cool down.
  3. Pour the cabbage water through a strainer into a jar or large measuring cup. The dark purple liquid in the jar is the pH indicator liquid. 
  4. Using a spoon, pour a few drops on to the substance you want to test. Some good things to test include water, juice, vinegar, baking soda in water and soap.

If the substance you are testing is an acid, the indicator will turn a bright red/pink colour. If the substance is neutral it should remain purple and if it is an alkali it will turn blue. 

Can you find out why the red cabbage indicator changes colours?