Mastering the concept of photosynthesis is of critical importance to learning plant physiology and its applications, but seems to be one of the more challenging concepts in biology. This teaching challenge is no doubt compounded by the complexity by which plants alter photosynthesis in different environments. Here we suggest the use of chlorophyll fluorometers in the undergraduate plant physiology classroom as one means to enhance conceptual learning of photosynthesis and its acclimation to changing environments. We also provide an overview of current research in photosynthetic acclimation to changing conditions, review the methodological considerations of making good "F[subscript v]/F[subscript m]" measurements with small inexpensive fluorometers, and suggest an open-inquiry activity for teaching concepts of photosynthesis and photo-acclimation with fluorometers in an undergraduate plant physiology course. (Contains 6 figures.)