Problems and possibilities for learning in an introductory chemistry course from a conceptual change perspective

Based on research on the effect of preinstructional knowledge on students' learning of chemical phenomena, this study explores individual learning processes in an introductory chemistry course (ninth grade of the German Gymnasium). The study focuses on four common everyday conceptions about two basic chemistry concepts: changes of substances and the particle model of matter. The question is how learning of these concepts is influenced and hindered by students' everyday conceptions about chemical phenomena. Questionnaire data were collected in four classes over one school year at six time points. The questionnaire items were tasks pertaining mostly to everyday problems. Data analysis of these items is based on five categories of answers including “everyday description” and “scientific explanation.” Results show some erosion of students' everyday conceptions in favor of scientific concepts, especially in their understanding of changes of properties of a substance as an indication that a new substance has been created. At the same time, some students' notions can be described as a mixture of everyday descriptions and scientific explanations. These students are “on the way” to the scientific concept but have not fully understood and accepted it during the project. Conclusions for teaching are as follows: a chemical concept needs to be taught in different contexts. Each new context gives students different opportunities to practice the new concept on similar tasks as well as to apply it to everyday phenomena. Second, knowledge of students' “mixed” conceptions allows teachers to develop more individual learning environments and also gives students an opportunity to understand their current location in their learning process. © 2001 John Wiley & Sons, Inc. Sci Ed 85: 158–179, 2001.