Problem Solver's Conceptions about Osmosis

What do you need to know to solve a problem? This question prompted my study of the conceptual knowledge of problem solvers. Conceptual knowledge is factual knowledge. It is the knowledge of the meanings associated with concepts, laws and theories. For this study, to solve means to construct not only a correct answer but a scientifically meaningful solving course. A meaningful solving course is a sequence of problem-solving operations that is driven by conceptual knowledge (Stewart 1982). By a scientifically meaningful solving course, I refer to a meaningful solving course that is driven expressly by conceptual knowledge that is both accurate and appropriate to the problem. The purpose of my study was to identify the conceptual knowledge of high school students who solved a significant problem about osmosis. The problem selected for this study is significant for both instruction and research in the domain of osmosis (see Figure 1). Firstly, the problem conditions have been displayed extensively in high school biology texts (e.g. Otto & Towle 1985; Schraer & Stoltze 1987). Moreover, similar osmotic systems are the basis for illustrations and laboratory activities in other textbooks and laboratory manuals [e.g. Biological Sciences Curriculum Study (BSCS), Yellow Version, 1980; Laboratory Inquiries, 1984]. Secondly, various researchers have used the conditions of this problem to explore students' conceptions about osmosis (Johnstone & Mahmoud 1980; Murray 1983). Osmosis is a fundamental but difficult concept for students to understand (Friedler, Amir & Tamir 1987). Therefore, to enhance the likelihood for a correct answer and a scientifically meaningful solving course, I selected participants who were designated as outstanding science students. Teachers recommended students who were outstanding in science for both their overall conceptual knowledge and interest in problem solving. Presumably their conceptual knowledge about osmosis could be useful for the majority of students to know.