Based on the analysis of available research on students' alternative conceptions about the particulate nature of matter, we identified basic implicit assumptions that seem to constrain students' ideas and reasoning on this topic at various learning stages. Although many of these assumptions are interrelated, some of them seem to change or…

The impulse to investigate the natural world is deeply rooted in our earliest childhood experiences. This notion has long guided researchers to uncover the cognitive mechanisms underlying the development of scientific reasoning in children. Until recently, however, research in cognitive development and education followed largely independent…