Testing and improving students' understanding of three-dimensional representations in chemistry.

Tuckey, Helen Patricia
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Three-dimensional visualisation is an important skill in chemistry but one in which many students experience difficulty. The main aims of this research were to identify the nature, extent and particularly the reasons for university students' difficulties in three-dimensional thinking and to devise teaching strategies for overcoming them. The research was restricted to the simpler aspects of three-dimensional thinking; it dealt only with rotation and reflection of simple molecules. The component steps required for the solution of three-dimensional problems were identified, and students' competence in these steps was tested. Pretest results showed that the students initially had poor visuaIisation skills. The main reasons for their difficulties were identified to be: (a) inability to visualise the three-dimensional structures of molecules, using the depth cues; (b) lack of precise understanding of the meaning of the phrases used in the questions (such as rotation about the X-axis; reflection in the XY plane); (c) inability to visualise the orientation of the axes and planes and of the positions of the atoms after an operation. A ninety minute remedial instruction programme on those aspects which caused difficulty was found to be enough, as shown by an analysis of covariance, to improve the students' visualisation skills very significantly (p < 0,01).
A Dissertation submitted to the Faculty of Education, University of the Witwatersrand, Johannesburg, for the degree of Master of Education.
Chemistry -- Study and teaching (Higher)