Qualitative study comparing the instruction on vectors between a physics course and a trigonometry course

Abstract

Science and engineering instructors often observe that students have difficulty using or applying prerequisite mathematics knowledge in their courses. This qualitative project uses a case-study method to investigate the instruction in a trigonometry course and a physics course based on a different methodology and set of assumptions about student learning and the nature of mathematics than traditionally used when investigating students' difficulty using or applying prerequisite mathematics knowledge. Transfer theory examined within a positivist or post-positivist paradigm is often used to investigate students' issue applying their knowledge; in contrast, this qualitative case-study is positioned using constructionism as an epistemology to understand and describe mathematical practices concerning vectors in a trigonometry and a physics course. Instructor interviews, observations of course lectures, and textbooks served as the qualitative data for in-depth study and comparison, and Saussure's (1959) concept of signifier and signified provided a lens for examining the data during analysis. Multiple recursions of within-case comparisons and across-case comparison were analyzed for differences in what the instructors and textbooks explicitly stated and later performed as their practices. While the trigonometry and physics instruction differed slightly, the two main differences occurred in the nature and use of vectors in the physics course. First, the "what" that is signified in notation and diagrams differs between contextualized and context-free situations, and second, physics instruction taught vectors very similar to trigonometry instruction when teaching the mathematics for doing physics, but once instruction focused on physics, the manner in which vector notation and diagrams are used differed from what is explicitly stated during mathematics instruction.