Learners combine different plant solutions -- made from fruits, vegetables, and flowers -- with equal amounts of vinegar (acid), water (neutral), and ammonia (base). They compare the color changes of each plant solution in each of the three solutions. Learners learn that plant color often depends on acid/base balances. This can be related to the idea that living systems must maintain a constant pH to survive, and that many plants require a specific pH in the environment to grow. This activity is currently used in the Biochemistry and Envrionmental Chemistry Units in OMSI's Chemistry Lab. Cost estimates are per 100 learners.