Evaporative cooling systems are commonly used in controlled environment plant and animal production. These cooling systems operate based on well defined psychrometric principles. However, students often experience considerable difficulty in learning these principles when they are taught in an abstract, verbal manner. This article describes an evaporative cooling demonstration model that has been used successfully in both the classroom and the laboratory to provide students with concrete, hands-on experiences with evaporative cooling and the underlying psychrometric principles. The model incorporates computer-based, real time data collection and display to visually reinforce the principles being taught and learned. Construction of the model was easily accomplished in approximately 2 hours at a materials cost of less than $40, excluding computer, instrumentation, and electric fan. (Contains 2 tables and 4 figures.)