RELATIONAL CONCEPTUAL CHANGE IN SOLUTION CHEMISTRY

This study explores changes to students' conceptions about solution ch emistry in the context of instruction based on collaboration between a researcher and an experienced teacher attempting to implement strateg ies from the literature on conceptual change. Conceptual change for st udents and teachers is viewed not just as a process of replacement of old concepts but also as a process of learning to relate ideas to appr opriate contexts. The process of instruction and collaboration was inf luenced by institutional limits on time, the press to cover the curric ulum, and the teacher's prior beliefs and practices. The study uses '' phenomenography'' to conceptualize students' understandings of solubil ity. Six categories of description were constructed: (a) physical tran sformation from solid to liquid; (b) chemical transformation of solute ; (c) density of solute; (d) amount of space available in solution; (e ) properties of solute; and (f) size of solute. After instruction stud ents showed evidence of two additional ways of talking about solubilit y: (a) chemical structure of components; and (b) solution equilibrium. The new language, however, did not necessarily replace initial ideas about what happens in particular instances of solution chemistry. A ca reful analysis of the students' conceptions of solubility revealed imp ortant factors influencing the nature of student learning in this area of chemistry. These factors include: (a) ambiguities of chemical theo ries about dissolving; (b) explanations of the observable; and (c) stu dents' chemical language. It is argued, in conclusion, that the goals for instruction are to assist students to appreciate contexts where ev eryday conceptions of chemical phenomenon are appropriate and contexts where particular conceptions from the community of chemists are more appropriate. (C) 1995 John Wiley & Sons, Inc.