The Harvard-Smithsonian Center for Astrophysics (CFA) will develop a modular, hands-on, discovery-based, intercurricular, multicultural physical science program for elementary students using astronomy as the central focus. In the first three years of the project will develop, field test, and pilot four modules in 60 third and fourth grade classrooms. At least half of the pilot classrooms will be in settings where underserved minorities comprise a major portion of the student population. The modules will be the initial components of a complete program, which, when finished, may serve as a basic physical science curriculum or as a complement to an existing course. Teacher enhancement videotapes will also be developed by the CFA's Science Media Group, featuring exemplary classroom teaching along with scientific background to the activities.