Investigating chemistry students' understanding of arrow -pushing formalism
Abstract
Starting with the simple premise that organic chemistry is hard, this research sought to provide information that can improve instruction. Unique to organic chemistry is the arrow-pushing formalism, a construct that describes the flow of electrons in an organic reaction. Little has been written about the teaching of arrow pushing formalism, and even less has been reported from a student's perspective. This study investigated differences in how undergraduate students in sophomore organic chemistry understood arrow pushing. Using a “think-aloud” protocol, 16 undergraduate chemistry majors each described their reasoning as they solved seven mechanism problems in a one-hour interview format. All interviews transcripts were given codes for analysis. These codes were analyzed using a qualitative approach for similarities and differences. Four overarching themes emerged from the analysis: (a) poor content knowledge becomes a barrier to success; (b) other non-arrow pushing barriers exist; (c) application of content knowledge facilitates success; and (d) problem solving strategies can either hinder or help answer the mechanism questions. Results can be summarized as follows: students defended their mechanistic route based on given structures; they manufactured answers in lieu of understanding fundamental concepts; and because, they know an answer does exist, they will invoke the mystical. In essence, students could provide a how, but were weak on why. The results suggested that the convention of arrow pushing formalism holds little meaning to the undergraduate student. This implies steps need to taken in the teaching of organic chemistry to rectify the problem. Some implications include emphasizing the themes of organic chemistry over the many details, rules and exceptions to the rules, relating arrow-pushing formalism (the microscopic/symbolic world) to the laboratory experience (the macroscopic world), and infusing active learning teaching strategies into the lecture course.
Degree
Ph.D.
Advisors
Bodner, Purdue University.
Subject Area
Organic chemistry|Science education|Higher education
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