Learners use a universal indicator to test the amount of sodium hydroxide needed to change the pH of plain water compared with the amount needed to change the pH of gelatin. Learners discover that living systems must maintain a constant pH to survive, and buffers help them maintain a constant pH in the presence of excess acid or base. This activity is currently used in the Biochemistry Unit in OMSI's Chemistry Lab. Cost estimates are per 100 learners. For safety reasons, this activity works best as a demonstration for younger audiences.