Visual models of chemical entities and reactions : perceptions held by grade 11 learners

Abstract

Learners of chemistry experience problems with the understanding of chemical reactions. One of the causes of this difficulty to understand chemical reactions seems to be that learners do not visualise them, or they do not know how to visualise them. The study aims at probing the learners' perceptions of visual models of sub-microscopic entities (atoms, ions, and molecules), to identify problems they encounter when trying to visualise and to understand chemical reactions. The empirical survey was conducted amongst 100 physical science Grade 11 learners from four high schools in the Bojanala West region near Rustenburg in the North-West Province, South Africa. The investigation was done by means of a questionnaire. The results of the questionnaire were used to identify alternative conceptions and problems that hampered learners' visualisation process. The results indicated that learners had problems with visualisation of the structure and the interaction of basic entities such as atoms, ions and molecules in chemical reactions. This had a negative effect on their understanding of chemical reactions and chemistry.