Sue tested her cabbage juice indicator on a wide variety of liquids!
What is a pH indicator?
A pH indicator is a compound in solution that will change colour when exposed to another liquid, depending on whether that liquid is acidic, basic, or neutral pH. Some of the pH indicators that we use in science labs are methyl red, bromocresol green, and iodine. However, there is an easy way to make a vibrant pH indicator right in your own kitchen, using red cabbage!
How to make your cabbage juice pH indicator:
Materials needed:
- 1/2 of a red cabbage
- knife
- saucepan
- strainer
- bowl to fit under strainer
- clear glasses and various (safe) liquids from around your home
Instructions:
- Chop the cabbage roughly
- Boil the cabbage in a saucepan, with just enough water to cover it, for about 10 minutes
- Cool slightly
- Pour the cabbage and water into a sieve that's sitting above a bowl to collect the "juice"
- Let that drain for a half hour or so
Experiment:
Set out small amounts of various liquids in clear glasses, and add a few drops of your indicator to each. Record your results and decide which colour indicates acidic liquid, and which basic!
An array of colours showing the cabbage juice reaction with various liquids
We would love to share this experience with you! Take a pic of your results and tag @WaterlooSci on Instagram or Twitter.