Red Cabbage Test

Using red cabbage to test if a substance is acidic or not.

Aim

To find out if red cabbage is a good and effective indicator by testing household substances.

Hypothesis

 

he red cabbage will work as an indicator but will not give consistent results.

Equipment/Materials

  1. water
  2. coffee
  3. milk
  4. apple juice
  5. blast™ dish washing concentrate
  6. Windex™ window cleaner
  7. large bowl
  8. glass cup
  9. red cabbage extract
  10. vinegar
  11. cinnamon
  12. bi-carb
  13. tablespoon
  14. measuring cup
  15. small bowl

Variables

Independent:

  • Household substance

Dependent:

  • Color of red cabbage extract

Controlled:

  1. Cabbage extract: should be the same concentration, temperature and age
  2. Equipment: should be cleaned after use to stop other chemicals interfering
  3. Amount of chemical: there should be the same amount of extract and the same amount of household chemicals in each test
  4. Repeat trials: should contain the exact same chemicals, same brand, age and temperature
  5. The same or very similar measuring equipment and containers should be used

Procedure

  1. Mix equal parts red cabbage extract and water in a large bowl
  2. Put 1 cup of the red cabbage solution into a small bowl
  3. Measure 1 tablespoon of water (used as a control) and put it into the small bowl with the red cabbage solution
  4. Mix the water and red cabbage extract together and then pour into a glass cup
  5. Mix the solution again
  6. Record the changes and clean equipment
  7. Get another cup of the red cabbage solution and put it into the same, cleaned, small bowl
  8. 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)
  9. Pour the contents of the small bowl into the cleaned glass cup and give a little mix
  10. Record the results and clean equipment again
  11. Repeat steps 7 to 10
  12. 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.
  13. Make a report showing the results

Results

The results for each household ingredient are listed below:

Chemical Color Change
Water None
Coffee Coffee color
Milk Milky white
Apple Juice Apple color
Blast™ Dishwashing Concentrate Purple-blue☺
Windex™ Green
Vinegar redish
Cinnamon Cinnamon color
Bi-carb Blueish

Discussion

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.

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6 Responses to “Red Cabbage Test”
  1. mik Says...

    On August 10, 2008 at 3:31 am

    this experiment is very good for high school students and i recomend it for a student doing a assignment for grade 8 – 9. it is one of the best ones i have seen round for a long time and i plan to use it with my students in the future and so should the other teachers out there. Because we need to know wats in our liquids that we use in our daily lives . xx thx mikki


  2. i luv fob Says...

    On August 19, 2008 at 6:45 am

    i luv fobb theyre soo awesummmmmm!!!!!!!!!!
    thnks fr this it help me with my science fair


  3. austin reed Says...

    On January 25, 2009 at 4:34 pm

    i like it


  4. Zac parker Says...

    On May 4, 2009 at 5:49 am

    i am a 8th grade student and i highly recomend this expiriment it got mii top marks even thou im not a science nut!!!!


  5. MeLiia baybiee Says...

    On March 24, 2010 at 3:20 am

    i better recieve a great result for my assignment. =)


  6. s dems Says...

    On January 18, 2011 at 3:13 pm

    Really good my teachers going to like it


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