Evaluation of chemical representations in physical chemistry textbooks

Abstract

That different levels of representation are important for complete understanding of chemistry is an accepted fact in the chemistry education community. This study sought to uncover types of representations used in given physical chemistry textbooks. Textbooks play a central role in the teaching and learning of science (chemistry), and in some cases textbooks are the curriculum (Chiappetta and Fillman, 2007; Gkitzia et al., 2011). The books are not only central to instructors' curriculum; they are also a major resource for students' reference especially outside of class. Using a coding rubric developed by Gkitzia et al. (2011), the physical chemistry textbooks were analyzed to determine at what level(s) the included representations conveyed chemistry content. Representations were also analyzed for their characteristics or features. Results indicate that the analyzed texts contain at least one representation on 95% of the sampled pages and, on average each page contains about 1.4 representations. The vast majority of the representations are symbolic level representations, accounting for about 85% of representations. Particulate or submicroscopic representations were in a slightly higher proportion than macroscopic and multiple representations, but these collectively only accounted for about 15% of the representations in the textbooks. Our results indicate no significant difference in the types of representations used in textbooks for chemistry and life science majors. Across editions of a number of textbooks, there does not seem to be a difference in the type and proportion of representations used. An analysis of the representations showed that virtually all were completely related to the accompanying text, had surface features that were clear and explicit, and captions were concise, explicit and completely described associated representations. Implications of our findings to the chemistry education community are described.