The development of pedagogical content knowledge in science teachers: New opportunities through technology-mediated reflection and peer-exchange

This design-based research study investigates the development of pedagogical content knowledge among nine teacher-participants (N = 9) in three design phases. PCK is a particular type of teacher knowledge that addresses not only the teacher's understanding of the content to be instructed, but also ways of how to teach that content effectively. This knowledge has been well documented over several decades, and is seen as central to teacher expertise. However, its actual development has been difficult for researchers to investigate. This study offers a detailed perspective on how teachers developed PCK with their engagement in lesson planning and enactment of a project-based technology-enhanced lesson. The study includes two specific interventions designed to enhance teachers' development of PCK: (1) scaffolded reflection that occurs throughout the practices; and (2) peer-exchange of lesson plans, enactment ideas, and completed reflections.;This study allowed some insight into how PCK develops as a result of teachers' engagement in the complex set of activities that constitute the practices of lesson planning and enactment. The primary implication of this study is that engaging teachers in scaffolded reflections and peer exchange can be a valuable in-service professional development activity. A methodological strength is derived from an approach to coding teachers' lesson planning and enactment according to an activity systems perspective, drawing on a spectrum of data sources (e.g., wiki-based reflections, planning artefacts, videotaped classroom enactments). Teacher learning---particularly the development of PCK---is recognized as critical in promoting student understanding of science concepts. This dissertation lays out a possible foundation for professional development models that promote effective teacher learning.;The findings demonstrate that teachers improve their planning and enactment of project-based technology-enhanced lessons with scaffolded reflection and peer exchange. Positive correlations were seen between teachers' engagement in the reflections and the quality of their lesson planning. Teachers who participated more deeply in the scaffolded reflections were able to understand how their lesson plans and enactment patterns fostered student understanding of relevant science concepts. Positive correlations were also seen between community influence and teacher lesson plans and enactment. Additionally, positive correlations were confirmed between teachers' level of participation in the peer exchange activities and the quality of their lesson planning and enactments. Teachers who contributed more deeply within the online and face-to-face peer community meetings benefited from the different perspectives of their peers about student learning and the best ways to succeed with project-based instruction.