Colour changing chemistry
Make your own universal indicator in this classic kitchen experiment to test for acids and alkalis.
Acids and alkalis in the environment make a big difference. Acid rain dissolves rocks and harms plants. Excessive acidity in the oceans is eating away at our coral reefs and causing sea creatures to migrate. It’s the job of environmental chemists to test the pH of samples and to investigate the effect on people and living organisms.
Acids and alkalis in the environment make a big difference. Acid rain dissolves rocks and harms plants. Excessive acidity in the oceans is eating away at our coral reefs and causing sea creatures to migrate. It’s the job of environmental chemists to test the pH of samples and to investigate the effect on people and living organisms.
Instructions
Challenge
Make a rainbow! Can you work out from the colours what is acidic and what is alkaline?
Try
Lemon juice
Vinegar
Bicarbonate of soda
Fizzy drinks
Sugar
…and anything else you can think of!
Reference
N. Chigurupati et al., ‘Evaluation of red cabbage dye as a potential natural color for pharmaceutical use’, International Journal of Pharmaceutics. (2002) 241 293–299.
Download a copy of this activity sheet
- Under supervision, boil the cabbage and keep the water (you can eat the cabbage).
- Once cool, pour a little into glasses.
- Add things from your kitchen to make different colours.
Challenge
Make a rainbow! Can you work out from the colours what is acidic and what is alkaline?
Try
Lemon juice
Vinegar
Bicarbonate of soda
Fizzy drinks
Sugar
…and anything else you can think of!
Reference
N. Chigurupati et al., ‘Evaluation of red cabbage dye as a potential natural color for pharmaceutical use’, International Journal of Pharmaceutics. (2002) 241 293–299.
Download a copy of this activity sheet
| colour_changing_chemistry.pdf |
