With the help of an activity, …

1. Peel off three or four big cabbage leaves and put them in a blender filled one-half full with water. Blend the mixture on high until you have purple cabbage juice.
2. Pour the purplish cabbage liquid through a strainer to filter out all of the big chunks of cabbage. Save the liquid for the experiments to follow.
3. Set out three glasses, side by side. Fill each glass three-fourths full with cabbage juice.
4. Add a little vinegar to the first glass of cabbage juice. Stir with a spoon and notice the color change to red, which indicates that vinegar is classified as an acid. All acids will turn red when mixed with cabbage juice.
5. In the second glass, add a teaspoon of washing soda or laundry detergent. Notice how the liquid turns green, indicating that this chemical is a base.
6. Keep the two glasses of red (acid) and green (base) liquid for future reference. Fill the third glass of purple cabbage juice to show the color of a neutral solution.