- adult helper
- small head of red cabbage
- 2 large bowls
- very warm water enough to cover the cabbage in a bowl
- 2 or more clear containers
- white vinegar
- baking soda
- other foods to test such as lemon, soda, water, or yogurt
- Have an adult cut the cabbage in half. Coarsely grate 1 cup of cabbage into a large bowl.
- Pour enough warm water to barely cover the cabbage.
- Leave the cabbage mixture until the water turns purple.
- Pour the cabbage mixture into a strainer over another large bowl. Save the cabbage water in a jar for your experiments.
- Put ¼ cup of cabbage water into a clear container and add spoonfuls of vinegar. What color does it turn?
- Put ¼ cup of cabbage water into another clear container and add some baking soda, a teaspoon at a time. What color does it turn?
- Try testing foods and other things from your kitchen to see if they make the cabbage water change color.
The purple cabbage juice became blue-green when you added baking soda. Baking soda is a base. When you added vinegar it became pink. Vinegar is an acid. Acids and bases are a group of chemicals. Acids have certain things in common with each other while bases also have certain things in common. Acids, or foods containing acids, taste sour while bases taste bitter. Some acids and bases are too dangerous to taste so we test them in another way. You’ve made an indicator form red cabbage that tests some chemicals for us.
Experiment and info from “Kitchen Science” by Shar Levine and Leslie Johnston