Chemical representations serve as a cornerstone to guide the teaching of chemistry concepts. The influence that a chemical representation has on instruction is largely dependent on how well the viewer interprets the information in the representation. Teachers serve as a guide to the students as they point out and make connections between the features present in a chemical representation. To influence how well the teacher serves as a guide it is important to develop teachers' pedagogical content knowledge as it relates to visualizations. As a first step towards developing this area of teaching expertise it is crucial to develop an understanding of how preservice chemistry teachers perceive a variety of chemical representations. To this end, this paper presents a novel card-sorting methodology that utilizes Johnstone's triangle as a continuum to determine how chemistry preservice teachers perceive representations relative to the presence of each of the three representational levels: macroscopic, submicroscopic, and symbolic. This study has determined that this methodology is both valid and reliable among a group of chemistry preservice teachers. The participants were able to effectively detect the presence or absence of the macroscopic domain. However, there was greater variance when the symbolic and submicroscopic levels were present. In addition, variance among the participants’ responses also increased dramatically when multiple levels were present in one representation. This was largely a result of what key features the participant focused on while viewing the card. The variance results of this study, along with the accompanying rationales for the placement of the cards, serve to inform the development of practices to further foster preservice chemistry teachers’ pedagogical-visual-content-knowledge (PVCK).

中文翻译：

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确定职前化学老师对化学表示的理解的定量方法

化学表示法是指导化学概念教学的基石。化学表示形式对指令的影响在很大程度上取决于观看者对表示形式中信息的理解程度。当学生指出并在化学表示法中存在的特征之间建立联系时，教师将作为学生的指南。为了影响教师的指导水平，发展与可视化相关的教师的教学内容知识非常重要。作为发展这一教学专业知识领域的第一步，至关重要的是要了解职前化学老师如何看待各种化学表示形式。为此，本文提出了一种利用约翰斯通（Johnstone）的新颖卡片分类方法 s三角形是确定化学预科教师相对于三种代表性水平（宏观，亚微观和象征性）中每种水平的存在如何看待表征的连续性。这项研究已经确定，该方法在一组化学预科教师中既有效又可靠。参与者能够有效地检测宏观域的存在与否。但是，当存在象征性和亚微观水平时，差异更大。此外，当一个表示形式中存在多个级别时，参与者反应的方差也显着增加。这在很大程度上是参与者查看卡片时重点关注的主要功能的结果。这项研究的方差结果