| As a result of the crucial role representations play in teaching physics, their use is an important aspect of teacher preparation. This study involved three training sessions for physics graduate teaching assistants (TAs) that presented different representational tools or strategies targeting important topics that are common in introductory physics courses. The content of the training sessions relied on physics education research findings while their design was informed by the framework of pedagogical content knowledge (Shulman, 1986a).;Fourteen participants from the Department of Physics and Astronomy attended the training sessions as part of a required Teaching of Physics course during the fall of 2007. Data on the TAs' use of representations included pre- and post-assessments, and observations of them while teaching recitations. Four expert physics teachers who did not participate in the training sessions served as a contrast group through the completion of the written measures.;The data show that the TAs recalled the content of the training sessions two to three weeks following the sessions. However, when teaching these topics in their recitations the TAs did not use the representations from the training sessions. They still relied primarily on a narrow selection of well-established representations such as mathematical representations and free body force diagrams. In addition, many did not follow established problem solving steps that were also a part of their training. This minimal impact of the training sessions on their teaching is explained in part by the TAs' lack of specialized content knowledge, a type of subject matter knowledge needed for teaching (Ball et al., 2008).;Based on the findings of this study, future TA training sessions should be designed to explicitly focus on both representational strategies and the specialized content knowledge required to successfully implement the strategies. |
