How do people determine if something is acidic or basic? Learners make their own acid-base indicators using red cabbage and then determine the acidity and alkalinity of different substances. First, they test substances of known pH and...

Using the natural pH indicator of red cabbage juice, groups determine the pH of different everyday liquids. As they work, pupils gain an understanding of pH that may help deal with contaminants in the water supply. 

Students take advantage of the natural ability of red cabbage juice to perform as a pH indicator to test the pH of seven common household liquids. Then they evaluate the accuracy of the red cabbage indicator, by testing the pH of the...