At the University of Alberta, graduate students were required to act as laboratory demonstrators in the Physiology courses given to medical, science, and nursing students. One of the laboratory sessions was about "respiration," and experiments involved measuring such things as tidal volumes, functional residual capacities, vital capacities, etc. The students had to obtain samples of oxygen and carbon dioxide from the gases they exhaled, as well as samples of room air, to make a comparison. On many occassions, nursing students, our future health care professionals, would ask demonstrators where they can get samples of room air. Tired of being repeatedly asked the same question, one demonstrator thoughtfully and carefully labeled a large gas-sample bag "ROOM AIR." Enthusiastic nursing students, continuing to ask where they could find room air samples, but now were being directed to the large air bag in the center of the laboratory. Everyone seemed happier.