You may be familiar with the sour taste of a lemon but have you thought about why its tangy flavor packs such a sour punch? Lemons are sour because they contain citric acid which is a weak organic acid found in many citrus fruits like oranges, lemons and limes.
In this At-Home Science experiment, aired on WJLA’s “Outside the Classroom” on May 1, 2020, Learning Undefeated VP of Communications Janeé Pelletier demonstrates how red cabbage juice can be used as a pH indicator to determine whether certain liquids are an acid or a base. Red cabbage juice is usually a deep dark purple color but it turns red when added to an acid or green when added to a base. Red cabbage juices is the best known edible pH indicator in your kitchen but there are many safe fruits, vegetables and flowers that change color in response to acids and bases such as eggplant, beets, blueberries, cherries, onion, raspberry, grape juice, turmeric, and even tomatoes!
Check out our At-Home Science page for full instructions and a downloadable laboratory protocol for this experiment!