Color your world with cabbage and learn about chemistry! The terms acid and base describe chemical properties of many things we use everyday. An acid is a substance that donates hydrogen ions, and a baseis a substance that accepts hydrogen ions. Sometimes, you can tell if something is an acid or base by the way it tastes. Acids, like vinegar, are generally sour. Bases generally taste bitter. (But heads up —some acids and bases are dangerous, so we don’t recommend tasting unknown substances!) Instead of a taste test, chemists use a pH scale to measure the strength of acids and bases. The lower the number on the pH scale, the more acidic something is. In this project, you’ll test different substances in purple cabbage juice and compare the results to a printable pH scale.