Red Cabbage Indicator Colors: Chemistry Experiment for Kids to do at Home 

 Explanation: In this experiment, the natural indicator used here is obtained from Red Cabbage. The pigment that gives red cabbage its color is called anthocyanin. This water-soluble pigment is also found in apple skin, plums, poppies, cornflowers, and grapes. 

Anthocyanin acts as a good indicator of acids and bases and can be used for a variety of household articles to detect whether they under an acidic or basic category. All acidic solutions, having pH less than 7 will turn the indicator into a shade of red color. When added to something that is neutral (neither an acid nor a base), the red cabbage juice will remain of the same color, i.e. Purple, and the basic solutions, having pH more than 7, will give a shade of green or blue, when tested with the natural indicator. In the Experiment, the acidic lemon Juice turned Red whereas basic baking powder solution turned green. Therefore, it is possible to determine the pH of a solution based on the color it turns the anthocyanin pigments in red cabbage juice. 

Source: https://www.zlifeeducation.com/blog/natural-indicator-red-cabbage/