Acid or Base? The Cabbage Water Experiment

Acids and bases are science topics that most young children learn about by mixing baking soda and vinegar. As kids get older, they are often interested in which substances are acidic and which are alkaline. This fun experiment uses something you can buy very inexpensively — red cabbage.

Supplies

Glass bowl Saucepan or tea kettle Uncooked red cabbage Quart of distilled water Quart-size glass jar with lid Strainer

Heat up a quart of distilled water on the stove. While you wait for the water to get hot, tear the cabbage into small pieces and place them in the bowl. Once the water boils, pour it over the uncooked cabbage. (An adult will need to do this part.) Let the cabbage and water sit until it reaches room temperature. Then, pour the water into the jar, using the strainer to keep the pieces of cabbage out. If you are not ready to use your cabbage water right away, keep it in the refrigerator. When you are ready to experiment, mix a few drops of the blue cabbage water with different substances to see if they are bases or acids. If the substance is an acid, the water will turn red. If it is a base, it will turn green.

What Is the Science Behind the Cabbage Water Experiment?

Red cabbage contains a chemical called anthocyanin. The chemical is blue in its neutral state, which is why the cabbage water will be blue after the cabbage steeps for a while. Anthocyanin will turn red when mixed with an acid and a greenish color when mixed with a base.

Substances That You May Test With The Cabbage Water Include:

Bases — baking soda, window cleaner with ammonia, dishwashing liquid, Borax Acids — vinegar, lemon juice, coffee, soda

Is There a Geographical Connection?

Cabbage is a food commonly grown and eaten in Ireland, an island country famous for its music, dancing and legendary leprechauns. Another popular legend centers around the Blarney Stone, which is part of Blarney Castle. Rumor has it that if you kiss the stone, you’ll never be at a loss for words, as you’ll receive the “gift of gab.” If you often aren’t sure of what to say, this would be a great place to visit someday!