skip graphical navigation
PBS KidsZOOM Home Back to Activity
Science Rocks!


Cabbage Juice Indicator

next

your results

Sent in by:
Jacob of LA

It's ZOOMsci...in the kitchen. And Fannee Doolee says: "When you're done here, check out the Kitchen Chemistry online game for more scientific kitchen kOOkineSS!"
Materials

Materials Needed


  • head of red cabbage
  • medium-sized bowl
  • grater
  • cold water
  • strainer
  • plastic container
  • clear plastic cups
  • baking soda
  • various liquids to test like lemon juice, vinegar, cola

Instructions

Instructions


  1. Check with a grown-up before you begin.
  2. Use red cabbage juice to find out if a liquid is an acid. Red cabbage juice contains chemicals that cause the juice to change color when it is mixed with some certain other chemicals. The cabbage juice will turn different shades of red when mixed with acids, and different shades of blue when mixed with bases.
  3. First you need to prepare your cabbage juice:
  4. Grate some red cabbage into a medium-sized bowl.
  5. Cover the cabbage with cold water and let it sit for 45 minutes.
  6. Strain the juice into a plastic container.
  7. Pour an equal amount of cabbage juice into each plastic cup.
  8. Add 1 teaspoon of baking soda to all but one of your cups. The baking soda (which is a base) will turn your cabbage juice blue. Now you can test different liquids to see how much of each it might take to turn the cabbage juice back to its original color. If the juice looks like it is turning back, the liquid you added is probably an acid. The cup without the baking soda is your control. This is the color that you want to get all of your mixtures to match.
  9. Get permission to test different liquids. Add your first liquid, one teaspoon at a time, to your first cup. How much do you need to get your original color? Test the rest of your items in the same way.
  10. It will take different amounts of different acids to turn the juice back to its original color. If the juice stays blue, the liquid is probably not an acid.


Try it out and be sure to send any discoveries you make to ZOOM.

Some of your Results

Albert, age 6 of Saratoga, CA wrote:
When I added various things, like lemon juice and baking soda, I noticed a very big difference. Lemon juice made the cabbage juice red-pinkish, and baking soda made it dark blue.

Sally, age 10 of Columbus, OH wrote:
It changed color when I added the lemon it turned into a pinkish color. I also found out something about the ph level. When it is at 7 then is regular water when it is lower than it is an alkali and it turns into a greenish and blueish color. If it goes higher than seven than it turn pink or red.

Maria of Tumaco wrote:
los colores cambiaron de una manera fascinante. Gracias (Translation: changed colors in a fascinating way. Thanks)

Sam, age 14 of Newton, MA wrote:
So cool, I tried it too and it was great!

Takille, age 11 of Wailuku, HI wrote:
I tried it and it was so amazing and I tried it with my parent and they said you are good at making an experiment.

Vardhani of Hyderabad, India wrote:
it was wierd when you put in vinegar, turned pink

Sam, age 12 wrote:
My class and I tried out this experiment for a grade. It was really cool... My teacher is going to let us do extra credit and mix other acids or bases with cabbage juice. I thought playing your game on this would be cool, and I got extra credit!!!

Nena, age 16 of Paterson, NJ wrote:
I love this project. it was very fun. the cabbage juice turned into many colors. I wish I could do the project again.

Natalie, age 11 of New York, NY wrote:
when I did this experiment I got different shades of blue but when I put vinegar inside the cup of cabbage juice with no baking soda it turned pink!!

Brooklyn, age 7 of OH wrote:
it was so good. it was awesome. we (my mom dad brother siser and me) loved it!!!

Arielle, age 11 of Tulsa, OK wrote:
I tested vinegar and it turned it pink, acid. Lemon juice turned pink, acid. 409 greenish blue, base; ammonia turned green, base. It was sooo fun!!!

Jonathan, age 11 of Starkville, MS wrote:
the lemon jiuce turned the stuff green.

Blane, age 10 of Fairhope wrote:
I mixed that with lemon juice and turned pink so it made an acid!

Marisava of MS wrote:
My class and I did litmus paper with cabage juice and it stinks. I cannot stand the juice

Kayla, age 7 of Yorba Linda, CA wrote:
It chage its color.

Sally, age 10 of Calgary, AB wrote:
the acids turned the juice different colours

Sarah, age 14 of Ocoee, FL wrote:
We did it at school with cabbage juice and pH paper which both came out with the same results.

Manya, age 12 of Delhi, IN wrote:
hi to all when I mix lemon juice (acid) into cabbage juice it changed its colour into purple...

Sarah, age 7 of Pennsylvania wrote:
It turned acid base or neutral it was realy cool!

Alex, age 12 of Hoffman Estates, IL wrote:
I usually dont like any tipes of vegies but now I shure do like cabbage! We ( my Dad sisters and me) added lemon juice for the acid and as the diretions suggested viniger as our base. After just a few minuts changed colors dramatically first deep blue then after the lemons back to purple. Thanks for this cool experiment Zoom!!!

Aaron, age 8 of Chicago, IL wrote:
we saw that 7 are a acid and all of them are acids

Christopher, age 12 of Guam wrote:
this is a really cool experment when you mix a base with a acid such as the cabbage juice and vinegar it turns differentshades of blue but when you ad the acid it neutrilizes the base turning it back to its original coler

Keyonie, age 10 of Philadelphia, PA wrote:
it turn to diffrent colors

Alexis, age 11 of Orlando, FL wrote:
it turned into different colors it was very interesting looking at it I noticed it was acid and I did add lemon juice to see what it did without cabbage juice.

Jalissa, age 10 of Chicago, IL wrote:
the cabbage juice indicator was so cool I put lemon juice in it and it charge to a pink gray color I like it

Jen, age 10 of Adelphi, MD wrote:
The when lemon juice (an acidic)was added, the purple-like pigment turned pink, and when baking soda (a basic)was added it turned blue-green. P. S this is my science fair experiment for 2008.

Vanessa, age 13 of Corona, CA wrote:
it changed pertty colors

Jessica, age 13 of Goose Creek wrote:
i got a red cabbage boied it and I put the red cabbage juice in a cup I indicated it with litmus paper and it was an acid

Alexis, age 13 of Huntsville, AL wrote:
i tested milk lemon juice pickle juice and coke and they all were acids except 2

Ryan, age 9 of Raleigh, NC wrote:
I tried this thing when I added bleach to the juice the color went weird.

Crystal, age 15 of Honolulu, HI wrote:
When I put the mouthwash into the cabbage juice it changes to kinda light blue color and its pretty too. It was alot of fun.


not yet implemented