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In recent years, chemistry educators are increasingly adopting immersive virtual reality (IVR) technology to help learners visualise molecular interactions. However, educational studies on IVR mostly investigated its usability and user perceptions leaving out its impact on improving conceptual understanding. If they evaluated students' knowledge gains, they tended to use information recall tests to assess knowledge gains. Employing interviews and diagram-drawing tasks, this study explored how students' conceptual understanding of the nature of hydrogen bonds and the shape of snowflakes changed through a collaborative IVR experience on snowflakes. Participants were 68 undergraduate chemistry students. Videos of pre-/post-interviews and student-generated diagrams were analysed. The results indicated a marked improvement in students' conceptual understanding of the nature of hydrogen bonds among water molecules in snowflakes. After IVR, 57 students provided scientifically acceptable explanations of the nature of hydrogen bonds. Improvements in students' understanding were related to the intermolecular nature of hydrogen bonds, the role of lone pairs of electrons in forming hydrogen bonds, and molecular interactions in 3D space. This study suggests that collaborative IVR could be a powerful way for students to visualise molecular interactions, examine their alternative conceptions, and build more coherent understanding. Implications for the design and implementation of IVR activities for science learning are discussed.

Recent studies have reported a growing trend of using student-generated diagrams for assessment in science teaching and research. However, many educators tend to use diagrams to explore students' perceptions of scientists and their work rather than explore conceptual understanding of abstract concepts. In this study, we used diagrams to investigate students' conceptual understanding of the nature of hydrogen bonds among water molecules in snowflakes. Participants were 70 first- and second-year university students. Following a sequence of interview prompts, the students drew diagrams to illustrate the interactions amongst water molecules in snowflakes. Sixty students' diagrams were analyzed inductively using a constant comparison method. Most diagrams showed that the students did not have major challenges drawing the water molecule structure, recognizing polarity of a water molecule, or recognizing the intermolecular nature of hydrogen bonds. However, the diagrams revealed varied ways in which students conceptualized the formation of hydrogen bonds. A third of the diagrams revealed students' alternative conceptions about the role of lone pairs of electrons in the formation of hydrogen bonds. Most diagrams which showed a good understanding of the nature of a hydrogen bond revealed students' difficulties in recognizing molecular interactions in a 3D space. Our findings suggest that student-generated diagrams can provide a powerful way to understand students' conceptions of abstract science concepts.

The advanced visualisation and interactive capabilities make immersive virtual reality (IVR) attractive for educators to investigate its educational benefits. This research reviewed 64 studies published in 2016-2020 to understand how science educators designed, implemented, and evaluated IVR-based learning. The immersive design features (sensory, actional, narrative, and social) originally suggested by Dede provided the framework for the analysis of IVR designs. Educators commonly adopted IVR to better aid visualisation of abstract concepts and enhance learning experience. IVR applications tended to have sensory and actional features, leaving out narrative and social features. Learning theories did not appear to play a strong role in the design, implementation, and evaluation of IVR-based learning. Participants generally reported their IVR experiences as positive on engagement and motivation but the learning outcomes were mixed. No particular immersive design features were identified to result in better learning outcomes. Careful consideration of the immersive design features in alignment with the rationales for adopting IVR and evaluation methods may contribute to more productive investigations of the educational benefits of IVR to improve science teaching and learning.

COVID-19 has thrust educators into a period of uncertainty, complicating conventional ways of teaching and learning. We suspect that the pandemic has magnified the challenges that some high school teachers already experience, particularly when they are the sole chemistry teacher at their school. The pandemic has likely inhibited collegial interactions and access to professional development (PD). Our reflections from redesigning a face-to-face PD program to one that is remotely delivered provide recommendations that advance PD accessibility and interactivity to mitigate isolation and other longstanding challenges teachers may face. In this article, we discuss how the cognitive learning model informed emergent teaching practices that guided the transformation of the PD's implementation for 20 high school chemistry teachers. Our reflections on the PD's strengths, areas for improvement, and insights alongside participant feedback provide enduring guidelines for fellow teacher educators. Specifically, we forward the importance of conceptualizing theory-informed design principles first, and then modifying the delivery with appropriate tools and technologies. As PD facilitators, we also draw attention to the necessity for flexibility. Remaining open to adaptation during implementation is crucial to advance teacher learning and engagement. We hope our process for how and why our PD program was redesigned will inspire future teacher educators to explore new, postpandemic ways of maximizing high-quality PD experiences.

The COVID-19 pandemic has fundamentally changed many aspects of our world including the way we teach chemistry. Our emergence from the pandemic provides an opportunity for deep reflection and intentional action about what we teach, and why, as well as how we facilitate student learning. Focusing on foundational postsecondary chemistry courses, we suggest that we cannot simply return to "normal" practice but need to design and implement new ways of teaching and learning based on fundamentally reimagined learning outcomes for our courses that equip students for life after the rupture they have experienced. We recommend that new learning objectives should be guided both by an analysis of existing global challenges and the types of understandings and practices needed to confront them, and by research-based frameworks that provide insights into important areas of knowledge, skill, and attitude development. We identify a core set of competencies along three major dimensions (crosscutting reasoning, core understandings, and fundamental practices) that we believe should guide the design, implementation, and evaluation of chemistry curricula, teaching practices, and assessments in foundational courses for science and engineering majors. The proposed framework adopts systems thinking as the underpinning form of reasoning that students should develop to analyze and comprehend complex global systems and phenomena.

Multiple-choice (MC) exams are common in undergraduate general chemistry courses in the United States and are known for being difficult to construct. With their extensive use in the general chemistry classroom, it is important to ensure that these exams are valid measures of what chemistry students know and can do. One threat to MC exam validity is the presence of flaws, known as item writing flaws, that can falsely inflate or deflate a student's performance on an exam, independent of their chemistry knowledge. Such flaws can disadvantage (or falsely advantage) students in their exam performance. Additionally, these flaws can introduce unwanted noise into exam data. With the numerous possible flaws that can be made during MC exam creation, it can be difficult to recognize (and avoid) these flaws when creating MC general chemistry exams. In this study a rubric, known as the Item Writing Flaws Evaluation Instrument (IWFEI), has been created that can be used to identify item writing flaws in MC exams. The instrument was developed based on a review of the item writing literature and was tested for inter-rater reliability using general chemistry exam items. The instrument was found to have a high degree of inter-rater reliability with an overall percent agreement of 91.8% and a Krippendorff Alpha of 0.836. Using the IWFEI in an analysis of 1019 general chemistry MC exam items, it was found that 83% of items contained at least one item writing flaw with the most common flaw being the inclusion of implausible distractors. From the results of this study, an instrument has been developed that can be used in both research and teaching settings. As the IWFEI is used in these settings we envision an improvement in MC exam development practice and quality.

A multi-institution collaborative team of Australian chemistry education researchers, teaching a total of over 3000 first year chemistry students annually, has explored a tool for diagnosing students' prior conceptions as they enter tertiary chemistry courses. Five core topics were selected and clusters of diagnostic items were assembled linking related concepts in each topic together. An ordered multiple choice assessment strategy was adopted to enable provision of formative feedback to students through combination of the specific distractors that they chose. Concept items were either sourced from existing research instruments or developed by the project team. The outcome is a diagnostic tool consisting of five topic clusters of five concept items that has been delivered in large introductory chemistry classes at five Australian institutions. Statistical analysis of data has enabled exploration of the composition and validity of the instrument including a comparison between delivery of the complete 25 item instrument with subsets of five items, clustered by topic. This analysis revealed that most items retained their validity when delivered in small clusters. Tensions between the assembly, validation and delivery of diagnostic instruments for the purposes of acquiring robust psychometric research data versus their pragmatic use are considered in this study.

Why is chemistry so difficult? A seminal paper by Johnstone (1982) offered an explanation for why science in general, and chemistry in particular, is so difficult to learn. He proposed that an expert in chemistry thinks at three levels; the macro (referred to as the observational level in this article), the sub-micro (referred to as the molecular level here), and representational (referred to as the symbolic level here). The observational level involves chemistry that is visible and tangible, incorporating what we can perceive with the senses. The molecular level of understanding consists of mental images that chemists use to imagine and explain observations in terms of atoms, ions and molecules. Observed phenomena and molecular-level processes are then represented in terms of mathematics and chemical notation at the symbolic level. In the early 1990s the VisChem project was funded to produce a suite of molecular animations, depicting the structures of substances and selected chemical and physical changes (Tasker et al., 1996), to address student misconceptions identified in the literature. For instance, only VisChem animations portray the vibrational movement in solid substances. This is important because this movement is correlated with temperature, and students need to understand this to interpret the significance of melting and boiling points in molecular-level terms. The need for a chemistry student to move seamlessly between Johnstone's three "thinking-levels" is a challenge, particularly for the novice. The author's work in the VisChem project indicates that animations and simulations can communicate many key features about the molecular level effectively, and these ideas can link the laboratory level to the symbolic level. However, the project has also shown that new misconceptions can be generated.

A prior study showed that students best make predictions about the outcome of opening a valve between two flasks containing a fluid or vacuum when they view both a demonstration video and a particulate animation, but the study showed no influence from the order in which these visualizations were used. The purpose of this current research was to study the effect of the order of visualization on students' particulate-level explanations. For this study, first-year general chemistry students in a south-central university in the United States were asked to choose, or type in their own explanations, for three experiments involving diffusion-effusion. Student ability to focus on particulate explanations was investigated after viewing either a macroscopic demonstration or an animated particle view. Students were directed to a Web site where they received one of two randomly assigned treatments. One group of students was shown the particulate animation first, followed by the macroscopic demonstration. For the other group, the order was reversed. Student explanations were assessed after each view. Finally, both groups were shown a side-by-side view of the animation and demonstration and their explanation was assessed one final time. Results showed that the order of visualizations did make a difference, with the macroscopic view followed by the particle view yielding significantly more particulate explanations. (Contains 7 tables and 8 figures.)

The article exlores the three levels of chemical education thinking proposed by A. H. Johnstone. Topics covered include the importance of the visualization at the molecular level for a deep understanding of chemistry, the Vischem Project which produced molecular animations, depicting the structures of substances and chemical and physical changes and how animations and simulations can effectively communicate many key features about molecular level.