A novel instructional computer simulation that incorporates a dynamic analogy to represent Le Chatelier's Principle was designed to investigate the contribution of this feature to students' understanding. Two groups of 12th grade Chemistry students (n=15) interacted with the computer simulation during the study. Both groups did the same pre-instructional and simulation activities except one of the groups interacted with the analogical example in the simulation and the other group was asked to recall an analogy that was presented in the form of text and pictures. A statistical analysis of the tests administered at the end of the study suggested that analogies that are dynamic, interactive, and integrated in a computer simulation may have a stronger effect on learning outcomes than analogies which are presented in the form of text and static pictures. The implication of this study for science educators is that dynamic computer-based analogies can enhance student learning of unobservable phenomena in science.