Discussion of explanations and knowledge representation within knowledge-based systems focuses on the development of an expert system for purification of proteins in a Swedish laboratory. Topics include domain conceptualization; a multiple-explanation construction model; a study of laboratory staff that investigated construed explanations; and…

Presents a framework characterizing cognitive models generated by sixth-grade students for simple opening/closing control mechanisms, like the elevator door. The students' conceptions, missing conceptions, and misconceptions are analyzed at three levels: device knowledge; perception of the control process; and perceptions of information flow. (LAM)