The role of submicroscopic and symbolic representations in chemical explanations

TLDR

Chemistry is commonly represented at macroscopic, submicroscopic, and symbolic levels, which together enrich chemical explanations. This article investigates how submicroscopic and symbolic representations contribute meaning to chemical explanations. The study follows Grade 11 students through lessons employing analogical, anthropomorphic, relational, problem‑based, and model‑based explanations, using teacher and student dialogues to show how these representations appear. Relational understanding is achieved only when submicroscopic and symbolic representations are used together, yet students often fail to recognize the teacher‑assumed role of these representations.

Abstract

Chemistry is commonly portrayed at three different levels of representation – macroscopic, submicroscopic and symbolic – that combine to enrich the explanations of chemical concepts. In this article, we examine the use of submicroscopic and symbolic representations in chemical explanations and ascertain how they provide meaning. Of specific interest is the development of students' levels of understanding, conceived as instrumental (knowing how) and relational (knowing why) understanding, as a result of regular Grade 11 chemistry lessons using analogical, anthropomorphic, relational, problem‐based, and model‐based explanations. Examples of both teachers' and students' dialogue are used to illustrate how submicroscopic and symbolic representations are manifested in their explanations of observed chemical phenomena. The data in this research indicated that effective learning at a relational level of understanding requires simultaneous use of submicroscopic and symbolic representations in chemical explanations. Representations are used to help the learner learn; however, the research findings showed that students do not always understand the role of the representation that is assumed by the teacher.