Substances in water: Learning progressions for designing curricular interventions

In this article, we present a learning progression framework for connecting chemistry curriculum to student reasoning about substances mixing in water and moving through environmental systems. We argue that model-based understanding of solutions and suspensions is necessary for informed engagement in public debate about environmental issues. Curriculum and instruction that supports students in developing this model-based reasoning must be responsive to student ways of viewing the world and support students in developing more model-based perspectives. We present an evidence-based learning progression for substances in water and propose principles for curriculum design and teaching of general chemistry topics based on this learning progression that attends to student thinking. We contend that a focus on students' meaning-making processes can inform the development and influence of chemistry knowledge in the public debate about water resources and environmental issues about water.