Cabbage Juice Chemistry: Experiment

“Cabbage Juice Chemistry” is a fun experiment demonstrating how to create an acid/base indicator at home.

Materials Needed:

  • a red cabbage to make cabbage juice
  • few plain glasses
  • white vinegar
  • baking soda
  • liquids like lemon juice, hand soap or shampoo, or orange juice.

Experiment Steps:

  • Chop a red cabbage into fine pieces and place it in a bowl.
  • Pour 2 to 3 cups of boiling water over the cabbage and let it soak for at least an hour.
  • Use a strainer to remove the cabbage and save the juice.
  • Pour some of the purple juice into the glasses.
  • Glass 1 – add baking soda and watch the solution turn blue or blue-green.
  • Glass 2 – add white vinegar and watch the solution turn pink.
  • Try lemon juice and dish soap in another glass and see the colors change!

Science Behind Cabbage Juice Chemistry

What’s A pH Scale?

  • pH scale is a way to measure how “sour” or “soapy” a liquid is. It goes from 0 to 14:
    • A liquid with a pH less than 7 is an acid and is “sour.”
    • A liquid with a pH of more than 7 is a base and is “soapy.”
    • A liquid with a pH of 7 is neutral, like water

What Makes Red Cabbage Special?

  • Anthocyanins are tiny color-changing superheroes inside the red cabbage.
  • Anthocyanin pigments can change color when they mix with different kinds of liquids.

Color-Changing Superheroes:

Anthocyanins react differently depending on the pH of the liquid they mix with:

  • Acids (like vinegar and lemon juice) make them red or pink.
  • Bases (like baking soda and dish soap) make them green, blue, or yellow.
  • Neutral liquids keep them purple.

Fun Facts

Here are some interesting facts about acids & bases:

  • Bases often feel slippery or soapy to the touch. Hence, soap and cleaning products are usually basic.
  • Bases are used in antacid tablets to neutralize excess stomach acid and relieve heartburn and indigestion.
  • Carbonic acid forms when carbon dioxide (CO2) dissolves in water, giving fizzy drinks their bubbles and slightly tangy taste.
  • Ant stings contain formic acid, which causes a burning sensation when you get stung.


Let’s quickly recap what we learned about cabbage juice chemistry:

  • What is a way to measure how sour or soapy a liquid is? pH Scale
  • What is a liquid with a pH of more than 7 called? Base
  • What are the tiny color-changing pigments in red cabbage called? Anthocyanins
  • What color does purple cabbage juice turn into when mixed with a base? Blue or Green
  • What color does purple cabbage juice turn into when mixed with an acid? Pink
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