The science classroom as a site of epistemic talk:two case studies of teachers and their students

摘要

Current science education documents emphasise both teaching the content and methods of science, and, promoting an understanding of the nature of scientific practices. One way of presenting the epistemic nature of science in the science classroom is foregrounding the role of argument in science. Argumentation is considered as a form of ’epistemic discourse’ that can enhance students’ epistemological understanding. Yet, little is known of the epistemic discourse initiated by teachers, either in ordinary or argumentation-based instruction. Therefore, this study explored the epistemic features of two science teachers’ classroom talk, as they engaged in argumentation and non-argumentation lessons. The extent to which student discourse was influenced by teacher discourse during argument-based instruction, and students’ views of theories and evidence, were also explored. An exploratory case study design was utilised. Teachers were observed teaching a Year 9 (13 lessons) and Year 10 (12 lessons) class throughout a school year. Other data collected included teacher interviews and field notes. One group of students from each class was also observed and interviewed. The analysis of classroom talk was based on ’epistemic operations’. The results showed how during argumentation lessons teachers engaged in the epistemic practices of construction, justification and evaluation. In non-argumentation lessons, classroom talk focused mainly on construction. The teachers’ classroom talk depended on their views of the nature and function of argumentation, and their perceptions of students’ difficulties with argumentation.The student talk modelled the teacher talk in the processes of justification and evaluation. Students engaged in epistemic discourse when they were confident of their knowledge of the topic discussed; the structure of the lesson was such that prompted them explicitly to engage in justificatory or evaluative processes, and, they were provided opportunities to discuss ideas in pairs before moving to larger groups. Implications for pre-service and in-service training that aim to promote argumentation in science education are discussed.