This project, sponsored by San Diego State University, will develop an inquiry-based, computer-supported, physical science course for the Middle School. The course, when completed, will cover the topics of properties and changes in the properties of matter, the structure of matter, motion and forces and the transfer of energy. The approach will be consistent with the National Standards and include the unifying themes of systems, models, constancy and change and equilibrium, the nature of science, the history of science and social issues related to science. The program will also make connections with mathematics as suggested by the NCTM Standards. The project will develop software that extends the activities of the prior work supported under the project called Constructing Physics Understanding in a Computer-supported Learning Environment. It will consist of six units: Applications and Systems and Interactions in (1) Systems and Energy, (2) Light and Color, (3) Sound, Electricity and Magnetism, (4) Motion and Forces, (5) Physical Changes, and (6) Chemical Changes. Each unit will be developed using the learning cycle approach supported by the software.