Transforming science learning through student-centered instruction that engages students in a variety of scientific practices is central to national science-teaching reform efforts. Our study employed a large-scale, randomized-cluster experimental design to compare the effects of student-centered and teacher-centered approaches on elementary school students' understanding of space-science concepts. Data included measures of student characteristics and learning and teacher characteristics and fidelity to the instructional approach. Results reveal that learning outcomes were higher for students enrolled in classrooms engaging in scientific practices through a student-centered approach; two moderators were identified. A statistical search for potential causal mechanisms for the observed outcomes uncovered two potential mediators: students' understanding of models and evidence and the self-efficacy of teachers.

This research examines factors influencing elementary science teacher learning as they participate in professional development with and enactment of educative curricula in comparison with learning following limited professional development and enactment of traditional curricula. Using a randomized cluster design (125 teachers and 2,694 students in 4th-5th grades) that met the What Works Clearinghouse standards without reservations, teacher learning was conceptualized using four outcomes. Data were analyzed using standard single-level multiple regression models and possible mediation models for the teacher outcomes were considered using piecewise multiple regression and path analytic approaches. Treatment group teachers experienced greater increases in content knowledge, views of science inquiry, beliefs about reform-based teaching, and teaching self-efficacy than comparison group teachers. The findings indicate that what teachers learn from the combination of professional development and teaching with educative curriculum varies according to what their knowledge and beliefs are on entering the experience. Surprisingly, high entry-level self-efficacy was associated not only with lower learning gains for the teachers, but also for their students. Finally, teachers' space science learning and that of their students are implicated as mediators of the positive effect of the professional development and educative curriculum enactment on teacher beliefs about reform science teaching. This work refines and extends a theoretical framework of teachers' participatory relationship with curricula.