Development of an Empirically Based Learning Performances Framework for Third-Grade Students' Model-Based Explanations About Plant Processes

To develop scientific literacy, elementary students should engage in knowledge building of core concepts through scientific practice (Duschl, Schweingruber, & Schouse, 2007). A core scientific practice is engagement in scientific modeling to build conceptual understanding about discipline-specific concepts. Yet scientific modeling remains underemphasized in elementary science learning environments, and little past research has explored early learners' engagement in domain-specific modeling practices. Here we report on a design-based study to investigate the ways in which third-grade students generate model-based explanations about two core plant growth and development processes: plant structure/function and plant life cycles. First, using design-based research, we developed and empirically tested a learning performance framework that integrates discipline-specific content with scientific practice to examine third-grade students' engagement in epistemic features of model-based explanations about plant growth and development. Next, we used the learning performance framework as a rubric to measure third-grade students mechanism-based scientific explanations generated from the models they developed prior to and after a long-term plant curriculum enactment. Findings from the learning performance highlight that students hold conceptual resources about plant processes and use this knowledge to reason in sophisticated ways. However, our findings from the pre/postmodels suggest that when students do not have opportunities to build conceptual knowledge, they depend on anthropomorphic analogies to reason about plant processes. Study findings imply that third-grade students require more sophisticated opportunities in building knowledge about how and why plant processes occur so they can use this knowledge to scientifically reason about how and why plants grow, develop, and survive. (C) 2016 Wiley Periodicals, Inc.