The impact of teachers' pedagogical knowledge of triplet relationship on their decision to teaching triplet in chemistry

Abstract

Since early nineties, Johnstone (1991) introduced the idea of three levels of representation in chemistry, the first is ‘descriptive and functional’, the second is ‘explanatory’, and the third is ‘representational’. These three levels of chemistry representation were named as ‘triplet relationship’ (Gilbert & Treagust, 2009). Despite considerable research evidence about the positive impact of explicit teaching of triplet relationship on students’ conceptual understanding in chemistry, it is not commonly seen in Hong Kong chemistry classrooms. The lack of enthusiasm among chemistry teachers in implementing this approach in teaching chemistry suggests that there are issues and concerns to be resolved before teachers see considerable advantages of this approach over their current practices. This study follows Boz and Boz’s (2008) arguments to explore: What and how much of pedagogical knowledge related to the triplet relationship do chemistry teachers possess, and does such pedagogical knowledge affect their decision to teach the triplet relationship in their lessons, and how? Three chemistry teachers were recruited for this multiple-case qualitative study. The data collected from each teacher includes field notes taken during the class observation, video record of all lessons observed, artefacts of lesson materials, and hours long in-depth interviews were conducted with each teacher. Simon’s pedagogical knowledge of triplet relationship is comparatively weaker than others, he thinks linking up any two levels is adequate. Pamela has good pedagogical knowledge of triplet relationship, she uses macroscopic as the core of teaching, followed by (sub)microscopic level explanation and symbolic level representation. Johnson has very good pedagogical knowledge of triplet relationship, he thinks choosing the appropriate context is the most important idea of teaching triplet, such as teaching with demonstration as the core for the topic of acid, focusing on particle theory for the topic of periodicity, and using graphs as the major pedagogies to teach equilibrium.