Reconceptualizing Out-of-Field Teachers' Professional Development and Classroom Implementation: A Boundary Crossing Approach

Reform-oriented instruction is advocated in secondary science, encouraging students to engage with the experimental and epistemic practices of science. It is challenging for teachers though, especially for out-of-field teachers. This study focuses on biology and chemistry teachers who are called to teach middle-school physics. These teachers face not only a knowledge gap, but also an epistemic gap arising from the distinct epistemic practices that are applied in the different school-subjects to construct scientific knowledge. We put forward a professional development (PD) approach for out-of-field teachers that capitalizes on the strengths and resources they bring from their original field of expertise, and describe design guidelines for a PD program designed to enable them to carry out inquiry experiences in physics with their students. Given our PD approach, we argue that successful classroom implementation should be framed differently for out-of-field teachers. Rather than expecting them to strictly implement the PD activities and thus completely change their familiar practice, successful implementation would entail modifications that integrate new practices with familiar ones. Using the boundary-crossing framework, we analyze three illustrative case studies in which teachers report on classroom implementation. We show how teachers remained rooted in their former practice - biology and chemistry instruction - and at the same time were inspired to adopt physics-oriented practices, for example integrating mechanistic reasoning and deductive approaches. Illustrating the different boundary crossing mechanisms the teachers applied and the boundary objects that mediated this process sheds light on new productive avenues for the PD of out-of-field science teachers.