TEACHING AND LEARNING DISTILLATION IN CHEMISTRY LABORATORY COURSES

This study investigates the problems chemistry majors have with learni ng distillation in traditional chemistry laboratory courses. Using an interpretive cyclic research design, we collected and interpreted data , mainly in the form of observation notes and transcriptions of the di scourse that takes place during laboratory courses. It was found that students experience numerous problems; these are described and interpr eted. We summarize students' problems in four categories: (a) students use an independent component conception; (b) they have insufficient u nderstanding of the properties of vapor; (c) they regard distillation from a physical point of view; and (d) they do not have a practical un derstanding of thermodynamics. The main origin of these problems was f ound to lie with the traditional curriculum structure. Lecture courses and textbooks treat distillation in a generalized and decontextualize d way, whereas decisions in actual distillations are always based on c ontextual features. It was found that textbooks and teachers often do not discriminate carefully and explicitly among five different context s for distillation: organic synthesis, chemical analysis, analytical c hemistry, physical chemistry, and preparation of products. Students ta ke the generalized concepts at face value and apply them to all distil lations regardless of context. They cannot interpret their observation s or make reasoned decisions based on the theoretical framework of a s pecific context.