Towards a Social Semiotic Interpretation of the Chemistry Triangle: Student Exploration of Changes of State in an Australian Secondary Science Classroom

Representations constitute an important part of chemistry knowledge. This paper revisits the notion of the term, symbolic, in the chemistry triangle proposed by Johnstone using the theoretical lens of social semiotics. In doing so, this paper proposes a framework of chemistry learning that highlights representational re-description and coordination as key mechanisms for facilitating connections among the three domains of knowledge: chemical phenomenon (perceptual-experiential level), macroscopic (theoretical-descriptive level) and submicroscopic (theoretical-explanatory level). This paper illustrates how this framework can be used to explore student meaning making of changes of state by examining students' interactions with the phenomena of melting and boiling and with the multiple representations of the phases of matter introduced in the classroom. The findings revealed the opportunities and challenges which emerged from student meaning making with multiple representations in the process of developing an understanding of the submicroscopic view of phase change. It also highlighted the support needed to facilitate such meaning making through representational re-description and coordination in order for students to develop a deep understanding of the logical connections between the particular model and the macroscopic patterns of the observed phenomena.