9806141 Gobert This research examines student learning in the domain of plate tectonics, as one domain representative of a difficult, causally complex domain encountered in middle school. A pilot study, which addressed the nature of students' pre-instruction models lead to the development of a typology of models, observed in middle school. These range from spatially incorrect models to causally complex models, which integrate multiple heat-related mechanisms (i.e., heated core, and convection currents forming), and movement-related mechanisms (currents pushing on the plates plates moving apart, etc.). The results of two empirical studies suggest that multiple inference tasks (i.e., diagram-based and explanation-based) could be used to promote model construction and revision. The goal of the present research is to identify modality-specific learning processes in each condition, namely, the diagram-construct and explanation-construct learning conditions. The findings, along with those from previous pilot data will be used to identify and refine a set of the earth and promoting the development of rich, integrated mental models. This approach to science, which emphasizes models and modeling tasks, recognizes the need to develop process skills such as model building in order to promote lifelong learning and scientific literacy. ***
