Laplace's Law plays a major role in explanations of the wall tension of structures like blood vessels, the bladder, the uterus in pregnancy, bronchioles, eyeballs, and the behavior of aneurisms or the enlarged heart. The general relation of Laplace's law, expressing that the product of the radius of curvature (r) and pressure (P) is equal to wall tension (T) (i.e., r X P = T), is quite simple, but students often have difficulties grasping its significance when applied to the organism. Various types of demonstrations and illustrations are used to familiarize students with the concept. In this article, an interactive demonstration of Laplace's law is described. (Contains 1 figure.)