Experienced teachers' development of pedagogical content knowledge for teaching a new topic

Abstract

New topics are continually being added to high school curricula to keep pace with scientific advancements; hence, it is not uncommon for science teachers to be required to teach new content. To date, however, little research has been conducted to investigate how experienced teachers develop the requisite knowledge for teaching new topics.

This multiple-case study employed Pedagogical Content Knowledge (PCK) as a lens to examine the topic-specific knowledge of six experienced teachers and the factors influencing that development. It is situated in a unique context — the teachers’ first attempts at teaching a new topic within their subject specialization. Data sources included classroom observations, field notes, semi-structured interviews and classroom artefacts.

The content and structure of the teachers’ initial PCK for teaching the new topic, Polymerase Chain Reaction (PCR), were captured and documented using Content Representations (CoRes), PCK reporting tables, teaching vignettes and modified PCK maps. Results show that the teachers developed PCK of different qualities, and that individual teachers’ PCK varied across the content themes of the topic. Teachers’ knowledge of students was the most frequently integrated PCK component, whereas knowledge of assessment was the least integrated component. Four teachers were chosen for in-depth case studies to illuminate the factors influencing their initial PCK development. Facilitative factors identified included strong subject matter knowledge (SMK), strong pedagogical knowledge, and a disposition to enact general instructional/pedagogical strategies conducive to PCK development. Inhibitory factors were didactic-rote learning science teaching orientations, weak SMK, rough lesson planning and faulty assessment practices. The findings suggest that experienced teachers’ prior teaching experience may facilitate teachers’ initial PCK development when the teachers: (1) aim at teaching for conceptual understanding; (2) have developed, based on their prior teaching experience, instructional/pedagogical strategies conducive to PCK development; (3) possess secure SMK of the new topic; and, (4) show the disposition for and commitment to enacting desirable instructional/pedagogical strategies in the context of teaching the new topic.

This study also explored the phenomenon referred to as on-site PCK development, in which teachers invented new instructional strategies/representations during the interactive phase of the lesson. It identified potential stimuli for on-site PCK development and the influence of various facilitating and hindering factors. The findings pave the way for further research into this oft-ignored method of PCK development.

This study contributes methodologically to the PCK literature by illustrating how the PCK map approach can be further refined to portray teachers’ PCK more comprehensively. Modified PCK maps visually depict teachers’ PCK along two important dimensions: the degree of integration among PCK components and the quality of selected individual PCK components. The study also makes a theoretical contribution by providing a refined understanding of how teachers’ prior teaching experience may affect new PCK development. The findings, as a whole, have practical implications for professional developers and address how teachers can be better prepared to develop new topic-specific PCK for teaching new content. This is a significant contribution, given that teachers are often required to teach new topics due to frequent changes in curricula and shifting teaching assignments.