This three-year project centers around the development of interactive videodisc case materials for use in the preparation of preservice elementary teachers. The Purdue University program will link with the Pennsylvania State University to develop, field test, and evaluate these videodisc. The intent of these materials is foster and develop the teaching of elementary science for conceptual change. The project will implement these videodisc case materials in elementary methods classes at universities. An extensive evaluation and research plan is in place to assess the effectiveness of these materials and their use. Over 450 students (preservice) will be affected by the project.