Exploring one aspect of pedagogical content knowledge of teaching assistants using the Conceptual Survey of Electricity and Magnetism

The Conceptual Survey of Electricity and Magnetism (CSEM) has been used to assess student understanding of introductory concepts of electricity and magnetism because many of the items on the CSEM have strong distractor choices which correspond to students’ alternate conceptions. Instruction is unlikely to be effective if instructors do not know the common alternate conceptions of introductory physics students and explicitly take into account common student difficulties in their instructional design. Here, we discuss research involving the CSEM to evaluate one aspect of the pedagogical content knowledge of teaching assistants (TAs): knowledge of introductory students’ alternate conceptions in electricity and magnetism as revealed by the CSEM. For each item on the CSEM, the TAs were asked to identify the most common incorrect answer choice selected by introductory physics students if they did not know the correct answer after traditional instruction. Then, we used introductory student CSEM post-test data to assess the extent to which TAs were able to identify the most common alternate conception of introductory students in each question on the CSEM. We find that the TAs were thoughtful when attempting to identify common student difficulties and they enjoyed learning about student difficulties this way. However, they struggled to identify many common difficulties of introductory students that persist after traditional instruction. We discuss specific alternate conceptions that persist after traditional instruction, the extent to which TAs were able to identify them, and results from think-aloud interviews with TAs which provided valuable information regarding why the TAs sometimes selected certain alternate conceptions as the most common but were instead very rare among introductory students. We also discuss how tasks such as the one used in this study can be used in professional development programs to engender productive discussions about the importance of being knowledgeable about student alternate conceptions in order to help students learn. Interviews with TAs engaged in this task as well as our experience with such tasks in our professional development programs suggest that they are beneficial.

Figure 1

Questions 3, 4, and 5 on the CSEM.

Figure 2

Figure provided for Q8 on the CSEM.

Figure 3

Q15 on the CSEM.

Figure 4

Diagrams provided for Q13 (a) and Q14 (b) on the CSEM.

Figure 5

Diagram provided for Q17–Q19 on the CSEM.

Figure 6

Diagram provided for Q22 on the CSEM.

Figure 7

Three situations and answer choices provided in Q25 on the CSEM.

Figure 8

Physical situation and answers provided for Q27 on the CSEM.

Figure 9

Diagram and answer choices for Q26 on the CSEM.

Figure 10

Diagram and answer choices for Q28 on the CSEM.

Figure 11

Diagram provided for Q29 on the CSEM.

Figure 12

Q32 on the CSEM.

Figure 13

Comparison of the percentages of correct answers predicted by TAs with algebra-based students’ actual performance after traditional instruction as obtained from Ref. [23]. Standard deviations range between 17.7 and 24.6 and are not shown for clarity.