Andy and his nephews make a beautiful colour changing liquid from cabbage juice, and explore the science of indicator solutions.
Make a liquid that changes colour.
ExpeRiment to see how the different substances change the colour of cabbage juice.
Learn about the science of indicator solutions and chemical reactions.
A quarter or so of a red cabbage
Water and other liquids to test such as vinegar, orangejuice, lemon juice, fizzy water, soft drinks, washing upliquid, liquid soap.
An egg (optional)
Bicarbonate of soda solution (put a few teaspoons into aglass, add water and stir well)
Clear glasses and a jug to pour liquids into.
Andy and his nephews Tom and Tom use chopped up cabbage to make a homemade indicator solution. They then experiment with different household liquids to see what colour changes occur. Their experiments with vinegar, bicarbonate of soda, eggs and anything else they can get their hands on show which liquids are acidic and which are alkaline.
Indicator solutions are important in chemistry, as they reveal useful information about the chemical compositions of other substances. In this experiment, acidic liquids turned the liquid red/pink, while alkaline liquids turned the liquid blue.
It’s fun to just look at the colour changes you can get with cabbage juice but this activity is a great way to introduce children to the idea that we can use chemical reactions to learn about the properties of substances.
Download the infosheet for more instructions and ideas. This series of ExpeRimental is supported by the Royal Society of Chemistry.