Let's build a model: how students incorporate evidence and mechanisms in models during small group discussion

Building a model to explain a scientific phenomenon is a central activity in an inquiry environment. This study investigated three aspects of model-based inquiry and developed coding frameworks to conduct quantitative and qualitative analyses. The first set of research questions examined learners’ capability of coordinating models with evidence. The second set of research questions scrutinized learners’ competence in incorporating mechanisms into models. The third set of research questions explored the dynamics of small group discussions and types of prompts that mediated varied modeling performances. A total of 80 pre-instruction models about cellular respiration were collected from 167 seventh graders from two schools to inform the first and the second sets of research questions. Discussion logs of four small groups and the conversations between groups and two teachers were analyzed to address the third set of research questions. The learners demonstrated proficiency in making their models consistent with an array of relevant evidence and eliminating irrelevant evidence, although a variety of prior knowledge was also present in a large portion of models. Mechanisms were incorporated into a majority of the models, and four types of them were identified. The design of the coding scheme made it possible to discover that most learners were able to indicate sequence in the mechanism, and it was less challenging for them to present entities in models than to incorporate entities into a mechanistic system. Higher performance was found to relate to factors identified by the third set of analytical instruments. Discourse processes such as contemplating multiple evidence all at once and stipulating a mechanistic explanation were more helpful than having an interactive discussion without their application. Moreover, higher performance might benefit from specific prompts than generic prompts offered by the teachers during their conversations with small groups. The triangulated results drawn from three aspects bring a comprehensive understanding of learners’ modeling accomplishment and how it can be influenced by certain discourse processes. The findings add to a growing body of knowledge about model-based inquiry and provide implications for small group discussions and instructional interventions in science education.Ph.D.Includes bibliographical reference