Making pH indicator test strips is surprisingly easy and I was very impressed with how well they worked. These are a lovely alternative or additional activity to making red cabbage indicator solution.
How to make pH indicator strips
Red Cabbage Indicator – made by boiling chopped red cabbage in water for 10 minutes
Vinegar/baking soda/lemon juice to test
Dip a piece of filter paper into the red cabbage indicator and leave to dry.
Once dry, drop the solutions to test onto the paper and watch as the colour changes
Solutions can be acidic, alkaline or neutral:
- an acidic solution is when an acid is dissolved in water
- an alkaline solution is when an alkali is dissolved in water
- solutions that are neither acidic nor alkaline are neutral.
Pure water is neutral.
An indicator is a substance that changes colour when added to an acidic or alkaline solution.
In a laboratory either Litmus or Universal Indicators are used. Litmus can only tell us if a substance is an acid or alkali while Universal Indicator tells us how strong the acid or alkali is.