Using red cabbage to test if a substance is acidic or not.
To find out if red cabbage is a good and effective indicator by testing household substances.
he red cabbage will work as an indicator but will not give consistent results.
- apple juice
- blast™ dish washing concentrate
- Windex™ window cleaner
- large bowl
- glass cup
- red cabbage extract
- measuring cup
- small bowl
- Household substance
- Color of red cabbage extract
- Cabbage extract: should be the same concentration, temperature and age
- Equipment: should be cleaned after use to stop other chemicals interfering
- Amount of chemical: there should be the same amount of extract and the same amount of household chemicals in each test
- Repeat trials: should contain the exact same chemicals, same brand, age and temperature
- The same or very similar measuring equipment and containers should be used
- Mix equal parts red cabbage extract and water in a large bowl
- Put 1 cup of the red cabbage solution into a small bowl
- Measure 1 tablespoon of water (used as a control) and put it into the small bowl with the red cabbage solution
- Mix the water and red cabbage extract together and then pour into a glass cup
- Mix the solution again
- Record the changes and clean equipment
- Get another cup of the red cabbage solution and put it into the same, cleaned, small bowl
- Put 1 tablespoon of a house hold substance into the small bowl and mix. (if the household substance is a solid, mix it with 25% water before putting it in the small bowl so that it will dissolve better in the red cabbage solution)
- Pour the contents of the small bowl into the cleaned glass cup and give a little mix
- Record the results and clean equipment again
- Repeat steps 7 to 10
- Repeat steps 7 to 11 but use a different household substance every time. Repeat until there are no household substances left or you run out of red cabbage solution.
- Make a report showing the results
The results for each household ingredient are listed below:
|Apple Juice||Apple color|
|Blast™ Dishwashing Concentrate||Purple-blue☺|
The experiment was made fair by keeping the working environment consistent between each test. The equipment was always cleaned after a chemical was used so that the chemicals would not react together and affect the colour of the mixture. There was only 1 batch of cabbage extract made so there was no difference between tests. There were repeat trials of each test to make sure that the result was consistent. Most of the time the test was only repeated a few times but when strange results occurred like in the windex™ the test was repeated several times to make sure that the chemicals were well mixed and there were no interferences. The same amount of chemicals was used each time, this made sure that the cabbage and chemicals had the same amount of power to react each time.