Some kitchen chemistry to help you determine the acidity of common household substances.
Chemistry doesn’t have to be dangerous or confined to a laboratory. Below is an experiment you can conduct in your kitchen to test whether common household substances are acidic, basic or neutral.
Red cabbage juice is a natural pH indicator. It will become purple to bright pink in acids and blue, yellow or green in bases.
You will need
- Half a red cabbage
- Chopping board and knife
- Kettle (to boil water for the indicator)
- Two large bowls
- Strainer or colander
- Five clear cups or jars
To test
- Half a cup of lemon juice
- One teaspoon of laundry powder
- Half a cup of white vinegar
- Half a cup of tap water
- One teaspoon of bi-carb soda
Making your indicator:
- Finely chop the red cabbage on the chopping board
- Place the chopped cabbage in a bowl
- Boil the kettle and pour the hot water in the bowl until it just covers the cabbage
- Stir a little bit and then leave for five to ten minutes. The colouring you can see in the water is your indicator!
- Place the strainer over the second large bowl and pour off the liquid
- Throw your cabbage in the compost
- Your indicator is now safely in your bowl
Testing your chemicals
- Label your cups
- Half fill cup with the test chemicals. Dissolve the laundry powder and bi-carb soda in a half a cup of water to make your solutions
- Add a teaspoon of indicator to each cup and observe the changes in colour. See table below to determine the approximate pH of your substances
