Data collected in this study indicated significantly greater pre-to-post test score gains, confidence level gains, and increased student engagement in learning about electric circuits through model-based instruction compared to students who learned through more traditional teaching methods. Since the teachers in the model-based group were known to widely utilize guided whole-class discussions to foster the students’ construction of explanatory models, it was deemed important to study the specific types of teaching strategies that may be supporting these positive effects. An in-depth analysis was conducted to identify teaching strategies used during whole class discussions by the two teachers whose students had the largest pre-to-post test gains. A new diagrammatic system for representing the parallel use of several nested levels of teaching strategies and their interaction with student reasoning moves was developed to support these microanalyses. This study found evidence that, in addition to previously documented dialogical strategies that teachers utilize to engage students in effectively communicating their scientific ideas in class, there is a second level of more cognitively focused model-construction-supporting strategies that teachers use to foster students’ reasoning about the construction of explanatory models of scientific concepts. A compendium was developed of thirty nine whole-class discussion-based teaching strategies, each of which contributes to one of four phases (Observation, Model Generation, Model Evaluation and Model Modification) of a model construction cycle. While the thirty nine strategies were identified within the teaching of high school electric circuits, it is believed that they are general enough to apply to other topics and levels of instruction. It was discovered that even though considerable differences were observed between two model-based teachers in the ratios of student and teacher contributions to the model construction process taking place during whole-class discussions, both teachers were able to support high levels of student participation in these conversations as well as virtually identical pre-to-post test gains in circuit problem solving outcomes. This result suggests that there is not “one best way” to facilitate model-based learning. The study attempts to contribute to a coherent model of how teachers can support students’ conceptual change processes through a process of scaffolding whole-class discussions.
Keywords: Model-based teaching & learning, mental models, whole-class discussion, high school physics, electricity, teaching strategies