The Roles of Representations and Tools in the Chemistry Laboratory and Their Implications for Chemistry Learning

In this historical and observational study, we describe how scientists use representa-tions and tools in the chemistry laboratory, and we derive implications from these findings for the design of educational environments. In our observations we found that chemists use representations and tools to mediate between the physical sub-stances that they study and the aperceptual chemical entities and processes that under-lie and account for the material qualities of these physical substances. There are 2 im-portant, interrelated aspects of this mediational process: the material and the social. The 1st emphasizes the surface features of both physical phenomena and symbolic representations, features that can be perceived and manipulated. The 2nd underscores