ABSTRACT
In this chapter, we review the evidence that elementary-school students need to make major conceptual changes to develop a sound macroscopic understanding of matter that in turn supports understanding the atomic–molecular theory in middle school. We place the development of these ideas within the broader context of a learning progression for matter, whose beginning lies in infants’ concepts of object and non-solids. We argue that this learning progression encompasses fundamental changes in a broad network of concepts – not only matter and substance, but also weight, volume, density, solid, liquid and gas – whose depth and scope have not always been clearly recognized by the science education community. Those changes are interrelated with changes in mathematical and epistemological understanding – about the validity of perceptual data unmediated by measuring instruments, the nature of numbers and measurement, and the role of theories and scientific models. We examine those conceptual changes and the difficulties they pose for students. For many students, the conceptions developed in early childhood are never revised sufficiently or even productively, suggesting that teaching about matter in elementary school needs to be rethought. We also present evidence that elementary-school students could achieve the necessary reconceptualizations with appropriate curricular support.
