Chemistry is fun and approachable with this hands-on activity that uses everyday materials to explore the world of acids and bases. In this experiment, students will create their own pH indicator using cabbage juice to test the acidity or basicity of common household liquids. From items you can easily find at the grocery store, students can observe how liquids like vinegar, water, and baking soda react to the natural pH indicator, revealing their chemical properties in a visual way.

Understanding pH, which measures how acidic or basic a substance is, is key to unlocking many concepts in chemistry. For example, neutral substances like water have a pH of 7, while acidic materials like vinegar measure around 2.5, and basic substances like bleach typically have a pH of 12. This experiment offers a perfect introduction to these concepts, making it accessible and engaging for students.

pH Scale PosterShop pH Scale Poster!

Supplies:

  • Red cabbage
  • Small cups or ice cube tray
  • Variety of different liquids (these are just suggestions, you can use anything!)
    • Lemon juice
    • Clear Soda (like Sprite)
    • Distilled water
    • Baking Soda
    • Vinegar
    • Apple Juice
    • Soapy Water
    • Hand Sanitizer

To Prepare the Cabbage Juice:

  1. Chop the cabbage into small pieces
  2. Boil cabbage in distilled water until the water turns purple.
  3. Strain the cabbage juice saving only the purple water
  4. Discard cabbage leaves.

Testing the Liquids: 

  1. In a small cup or ice cube tray, place a few drops of the cabbage juice and a few drops of the liquid you are testing.
  2. Make observations on what color the solution turns!
  3. Repeat with other liquids and determine which ones are acidic and which ones are basic!

   

Extensions and Going Beyond

Once students have created bright and vibrant colors with their solutions and cabbage juice, have students start to make other observations about the liquids. What are some of the similarities and differences between them? What are some qualities of acids and bases besides their pH?  How can this information be used by scientists and people in the real world? Where have you heard the word “acid” before?