This paper describes the background and development, provides an overview, and discusses the evaluation of the Carroll County, Maryland, elementary school science program emphasizing a hands-on approach to science. It uses locally developed materials designed at each grade level and focuses on process skills instead of concepts. The program development was guided by a statement of principles: (1) a hands-on approach and direct involvement of students; (2) concepts appropriate for the developmental level of students; and (3) extensive use of science processes. Instructional emphases are: (1) Grade 1--observation; (2) Grade 2--classification; (3) Grade 3--experimentation; (4) Grade 4--analysis; and (5) Grade 5--application. Materials needed for the program are supplied to teachers in custom-made kits developed for each grade level, designed and manufactured by Delta Education. Teachers receive trade books selected to match curriculum topics to supplement the curriculum. Summer enrichment materials have been prepared for each level. The lab-based approach was compared to two textbook based programs and found superior in amount of hands-on activity, inclusion of scientific processes, student motivation, and teacher motivation, but inferior for implementation. Subsequent reports include documentation of material development and curriculum guides for each grade level. (JM)