Preschoolers' Developing Knowledge of the Pan Balance: From New Representation to Transformed Problem Solving

Although it is generally accepted that a new representation of a physics task domain frequently underlies fundamental improvements in problem solving, there is less agreement and less understanding about the process of knowledge construction from emergence of first signs of new representation to transformed problem solving. This study examines that issue in the context of preschoolers' formation of a weight approach to achieve mechanical equilibrium on the pan balance. The study used a rich version of the balance-beam task and three levels of microgenetic analysis of the videotaped experimental sessions to elucidate this subtle transition. Cues employed included focus of visual attention, manipulation of materials and the apparatus, gestures, verbal protocol, and expressions of surprise. Forty-eight preschoolers (evenly distributed across sex and age groups) were each asked to balance the pans on a series of nine problems. Every problem consisted of a set of weights to be balanced, either identical or dif...