Reducing the degrees of freedom in chemistry classroom conversations
Five high-school chemistry teachers were asked to enact a lesson in which they posed a problem for which students were likely to generate solutions based on reasoning that was not aligned with accepted principles of chemistry. Four teachers selected a problem related to the stoichiometry of a reaction; the fifth chose a problem associated with periodic trends. The goal of the research was to understand the kinds of strategies used by these teachers to support students' progress towards more sophisticated conceptualizations of the phenomena being explored. Transcripts of teacher interviews and the discourse contained within the videotapes of the lessons were analyzed to identify similarities and differences in the strategies teachers employed. The data suggest that all of the teachers operated off a common lesson schema that caused them to implement certain pedagogical practices—especially certain discourse moves. This ‘traditional cognitive conflict’ schema from which the teachers' discursive practices seemed to be derived reduced the opportunities for them to gain full access into their students' thinking related to the principles underlying the problems posed. Moreover, it eliminated possible pathways the teachers could have laid down between the conceptions of students and those of chemists. For researchers this study suggests the need to further explore the prevalence of such practices and what prompts their utilization; for teachers this study shows the influence their choice of certain discourse moves can have on a lesson's conceptual trajectory.