You have heard about acids in foods, acid in coke, acid in your stomach and maybe even the word base. Understanding the chemistry of acids and bases really impacts your life as so many objects around you depends on the correct ‘strength’ of acid or base.  This experiment examines the chemicals in red cabbage that change colour in different pH solutions.
Materials
* Red Cabbage
* Clear containers
(glasses or test tubes)
* Mixer
* Pipettes (droppers)
* Various materials to test
1. Adults should use the mixer
2. Only test chemicals that are non-poisonous.
3. Don’t taste any chemicals
Get your mum or dad to cut up some red cabbage into strips or small pieces.
Fill the mixer half full of water and place the red cabbage inside. Turn it on and blend for 1-2min.
Strain the liquid into a large cup.
Pour a small sample of each solution to test into separate clear cups.
Use the pipette (or dropper) to place 5 -10 drops of the cabbage juice into each sample cup and mix. Observe the colour of each.
Check out the ‘Wacky Science’ video of this experiment and ‘What’s Going On’ series link. They are currently ‘In Production’, so check back soon…..
There are many substances around us that are acidic or basic. Your stomach has acid inside it to help digestion, bleach is used to clean clothes and pH is even important in your wee!
There is MORE information in our Bright Spark guides, but basically we can have a scale to measure how acidic or basic substances are. This scale is called the pH scale and runs from 0 pH to 14 pH.
Indicators are chemical substances that change colour in different pH environments. eg they may be red in acid and then blue in base.
Red Cabbage conains a chemical called flavin which changes colour in different pH solutions.
You should have found that it changes colour in acids (eg lemonade, citric acid) that are around a red colour. Neutral substances (water) were green and basic colours such as yellow-purple occured in substances that were basic.
If you would like
– more details,
– pictures of the second half of the experiment
– information on how to investigate this further
– links to everyday examples
– management hints & teaching pointers (5P Teacher develpoment program)
 ….. then why not subscribe to one of the following
(1) Crazy science Club
(2) 5P Teacher Training course called ‘Looney Lab  Classroom Creations‘
Or you can purchase the ‘Bright Sparkes Guide’ of this demonstration only ($2.50) which has:
- HD pictures of experiment steps
- Detailed explanation of science
- Mini-challenge section (another experiment)
- Making it a ‘Scientific Method’ experience
- Graphing opportunities
- REAL links and descriptions to everyday examples of concept.