Abstract
This study, a narrative inquiry into the teaching of models and modeling in an elementary science classroom, explores a teacher's growth in pedagogical content knowledge (PCK) as she implemented a novel curriculum adapted from the MoDeLS (Modeling Designs for the Learning of Science) project. The purpose of the study was to explore, from the teacher's point of view, the pedagogical and conceptual changes she underwent while implementing a model-based approach in her classroom. The study summarizes the teacher's experiences, her decisions about teaching, her understanding of how her choices and practices influenced her content knowledge (CK), her PCK, and her motivations for changing her teaching. During the three years of the project I collected data from four science units (Astronomy, Animal Science, Electricity, and Light). Each of the units were observed and videotaped and Ms. Delaney (pseudonym), the classroom teacher, audio-recorded her practices every day. I observed and analyzed classroom videotapes in order to explore how Ms. Delaney's modeling practices unfolded and changed in her classroom and how her PCK on modeling developed. I analyzed professional development activities and informal interviews conducted during and after the units. Subsequently I interviewed Ms. Delaney about these issues using open-ended questions and video clips of her classroom practices. Three aspects of models and modeling expressed in the MoDeLS project were taken into account as I developed categories of analysis: a) models have purpose; b) models have limitations; and c) models change. These categories and the codes proposed were revised and refined while analyzing the data. The findings from the interview analyses and the classroom practices showed that Ms. Delaney developed new CK around models and modeling throughout the three years she was involved in the project. She adapted some of the proposed strategies from the MoDeLS project and adopted them in her curriculum in ways that were consistent with the project's goals, thus shaping and adding to her PCK repertoire. Some activities were maintained through the years; in other cases there was a connection among CK development and her developing PCK. In all of these cases, there was a need for CK around modeling to be integrated into practice activities. However, her views and evaluation of the practice reflected a greater commitment to students' learning than to aspects of modeling related to scientific content or metamodeling. The structure presented in the MoDeLS activities makes sense to her from the pedagogical perspective. This made her inclusion of modeling into the science practices easier. There were complex interactions among learning new CK, new PCK sets from other units she was teaching, and her existing PCK on specific topics not necessarily connected to the modeling approach. These interactions played an important role in how Ms. Delaney was able to transform her PCK. There were some elements that were easily acknowledged and tried in her practice, while others were not reflected upon or included in her teaching. Whether some PCK elements were more or less included depended not only on Ms. Delaney's CK, her conception of learning and her confidence, but also on the quality of the examples provided and her professional development support as well as students' activities and learning situations. In conclusion all major PCK features were developed when Ms. Delaney integrated the modeling approach into her practice. Instrumental in shaping how her PCK grew were her advancement in CK comprehension and students' responses to the proposed activities. The findings are consistent with the idea that PCK is complex and deeply interconnected.
