Teaching and Learning the Many Faces of Chemistry
The goal of this chapter is to review research on teaching and learning science that focuses on the specific domain of chemistry, with particular emphasis on the high school level. Many chemistry topics can be either viewed or taught from three potential perspectives that are mutually related (Fig. 22.1). First, the macroscopic perspective, focusing on substances and phenomena that can be observed with the naked eye. Second, the submicroscopic perspective, focusing on molecules, atoms, ions, and so on. Third, the symbolic perspective, focusing on formulas, equations, ionic drawings, and the like. The use of this three-cornered relationship (Johnstone, 1991) is not exclusive to the chemical domain, but it plays a more dominant role here than in the domains of the other natural sciences. Many students experience difficulties in understanding the macro/submicro/symbolic triangle and, in particular, in appreciating how and when to make the transitions between the three perspectives. Teachers do not always realize the importance of modeling the relationships here, by being explicit about the perspective being used, and the transitions being made, and helping students to overcome their difficulties.