Presented is an analysis of a concept teaching technique that was developed according to a theoretical perspective which emphasizes the importance of a student's existing knowledge in influencing that person's subsequent learning. Significant differences between an experimental group which was exposed to this instructional strategy, and the control group which was not, are explained in terms of a conceptual change model. This paradigm emphasizes: (1) different ways in which a person's conceptions may be modified; (2) characteristics of a given conception that determine whether or not it will change; and (3) how a particular conception can change. The experimental strategy was effective because it directly addressed students' misconceptions and demonstrated the fruitfulness of the accepted science concept. It is thus important to reconcile the scientific view with each student's existing knowledge. (Author/WB)