The difficulties encountered by students in learning chemistry range from human factors to the intrinsic nature of chemistry. To enhance students’ understanding of chemistry, there is a wide consensus within the community of chemistry educators on the importance of and need to integrate different levels of representations in chemistry teaching and learning resources. As learning resources, textbooks are ubiquitous and usually readily available to both students and teachers. Therefore, this study investigated how chemical phenomena are represented or depicted in secondary school chemistry textbooks. We adopted a rubric developed by Gkitzia et al. (Gkitzia V., Salta K. and Tzougraki C., (2011), Development and application of suitable criteria for the evaluation of chemical representations in school textbooks, Chem. Educ. Res. Pract., 12, 5–14) to analyze the textbooks for types of representations; relatedness of chemical representations to text; and the appropriateness of captions. The results indicated the dominance of symbolic representations, followed by sub-microscopic, then hybrid and multiple representations. In all three textbooks, there was no evidence of mixed representation. While many of the chemical representations were completely related to the texts, some were unlinked. The germaneness of suitable captions in textbooks is in the explicit, brief and concise explanation that captions give to an entire representation. While our results indicated that more than half of the representations had suitable captions, there was evidence of representations that were problematic and had no captions. The implication of these results for students’ cognitive load, and the need for textbook-users to explore alternative resources that depict phenomena in 2D or 3D representations are discussed.

中文翻译：

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中学化学教科书中化学现象的表示

学生在学习化学过程中遇到的困难范围从人为因素到化学的内在本质。为了增强学生对化学的理解，化学教育工作者内部就在化学教学资源中整合不同层次的表示形式的重要性和需要达成广泛共识。作为学习资源，教科书无处不在，通常可供学生和教师使用。因此，本研究调查了中学化学教科书中如何表示或描绘化学现象。我们采用了由Gkitzia等人开发的专栏。（Gkitzia V.，Salta K.和Tzougraki C。，（2011年），制定和应用适当的标准来评估学校教科书中的化学表示，化学 教育。Res。实践。，12，5–14）分析教科书中的陈述类型；化学表示与文本的相关性；以及字幕的适当性。结果表明，符号表示法占主导地位，其次是亚微观表示法，然后是混合表示法和多重表示法。在所有三本教科书中，没有证据表明存在混合表示。尽管许多化学表示形式与文本完全相关，但有些化学表示形式却没有关联。教科书中适当标题的紧密联系在于标题对整个表示形式的明确，简短和简洁的解释。尽管我们的结果表明，超过一半的陈述都有适当的标题，但有证据表明存在问题且没有标题。这些结果对学生的认知负担有影响，