Starting with cabbage juice, students in Mrs. Crissy Giacona’s 8th Grade science class made their own pH indicator solution. Students added vinegar, ammonia, and a baking soda solution to look for a color change in the cabbage juice. Using a pH scale, the students determined the pH of the new solution.
Red cabbage juice contains a natural pH indicator that changes colors according to the acidity of the solution. The cabbage juice contains a pigment molecule called flavin (an anthocyanin). This natural pH indicator changes colors according to the acidity of the solution.
Very acidic solutions will turn anthocyanin a red color. Neutral solutions appear in a purplish color. Basic solutions result in greenish-yellow.