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We had so much fun experimenting with a cabbage juice science experiment recently. This is an awesome chemistry experiment for teaching about acids and bases.
Did you know that red cabbage juice contains a natural pH indicator that changes colors according to the acidity of the solution?
Very acidic solutions will turn it a red and orange colors. Neutral solutions result in a greenish color. Basic ( or alkali) solutions appear in blues and purples. So, it is possible to determine the pH of a solution based on the color it turns the red cabbage juice.
How to Do the Acid Base Cabbage Juice Science Experiment:
- Red Cabbage
- Large pot of boiling water
- Litmus paper or coffee filters (to make your own)
- Various substances to test the pH of
- Several cups- can use paper cups, plastic cups or glasses from home
This experiment would be great to use for a science fair project. It is simple to put together and can be done without acquiring too many extra supplies and ingredients.
How to Make Cabbage Juice:
You will need to start by making some red cabbage juice. Start by chopping up a head of red cabbage. We only used half a head for your experiment. You can save the other half for your dinner salads!
Put the red cabbage into a large pot & add water to cover. Boil until soft & the water is deep purple. Let it cool.
Remove the cabbage, but save the water! You can use the cooked cabbage in a yummy soup!
The easiest way to do this is to drain the water from the cabbage into another bowl with a strainer.
Pour the cooled cabbage water into small cups. Collect some household items that could create reactions (acid, base, neutral).
Cabbage Juice Litmus Test ~ Acids or Bases?
Now you are going to collect a variety of household substances to see if they are an acid, a base or a neutral.
Some ideas of things to test:
- lemon juice
- baking soda
- window cleaner
- hand sanitizer
- cola/something carbonated
- antacid tablets
- rubbing alcohol
- cream of tartar
- tomato sauce
Add a little bit of each substance into your cups of cabbage water- label the cups so you remember what you put into each one.
The Science Behind the Cabbage Juice Chemistry Experiment:
Cabbage juice is an acid-base indicator (a chemical that tells you something about other chemicals). If it turns a pinkish color, the substance was an acid. If it turns a greenish color it base. If it stays about the same, it is neutral. Also acids and bases can react to one another turning neutral. There is a whole color scale you can use to determine the exact levels!
Instead of pouring the substances into the cabbage water, you can also test the acidity by dipping litmus paper into the substance.
However, you can also tell if it is an acid or base by the color it turns the cabbage juice as I showed you above.
This was a simple & fun experiment! The kids loved guessing what would happen with each thing they poured into the cabbage water.
How to Make Your Own Litmus Paper:
Don’t want to buy the litmus paper? Or can’t find any?
You can make your own litmus testing paper from the cabbage water, too! It’s really quite easy. This will just make the experiment take a bit longer with the dry time.
This can be done with coffee filters or with paper towels. Cut them into small even strips.
Use the boiled cabbage water and dip the strips of coffee filters or of paper towels into the water. Lay them on a tray or a cooling rack with a tray underneath. Let them dry completely.
Use them the same way the litmus paper strips are used.
Do some more cabbage juice science and check out how we made Green Eggs with Cabbage Juice!!