This study investigated the organizational impact of computer technology on four secondary science teachers' teaching actions using the construct of community of practice. The organizational impact of computer technology refers to teachers' styles and creativity in constructing personally pertinent individual models of teaching when using computer technology: social participation structures. Analysis of data (observations and interviews) revealed three social participation structures that collectively orchestrated students' science content learning: (1) students' membership, (2) access to the structured tasks, and (3) confirmation of students' learning of science concepts. This study indicated that the transformative potential of computer technology for teaching science is a complex interplay between social participation structures, institutional context, and teachers' knowledge of what is good practice.