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The purpose of this study was to examine experienced chemistry teachers' pedagogical content knowledge (PCK) for two different topics in chemistry to better understand how PCK is specific to topic, including whether all components of PCK are topic-specific and to what degree. To explore the topic-specific nature of PCK, we examined two experienced teachers' PCK using a case study methodology. Multiple data collection strategies were used, including a card-sorting activity, Content Representation (CoRe), semi-structured interviews, observations, and field notes. The data collected were analyzed both deductively and inductively. Results revealed that the teachers used more content-based and teacher-centered instruction to teach electrochemistry, whereas their instruction was less teacher-centered, and included Science–Technology–Society–Environment discussions and implicit NOS instruction to teach nuclear reactions. The teachers also varied in the extent of their knowledge of learners and curriculum in comparing their PCK for each topic. In regard to assessment, the teachers' assessment practices were at the general PK level; they lacked topic-specific PCK for either topic. We provided recommendations for professional development programs, pre-service teacher education programs, and curriculum developers to support teachers in developing topic-specific PCK.

Students' understanding of the orbital concept has been subject to considerable research and debate and often found at variance with a quantum mechanical ideal. Could it be the case that orbitals as actually used by practising chemists in teaching and research also differ from that ideal? Our experience shows that this might often be the case. Through a series of examples of pictorial representations of orbitals found in textbooks and other educational materials, as well as in research papers, we argue that this is a common situation, which deserves to be stated explicitly. We point out that, in particular, there is a way in which orbitals are frequently employed deeply rooted in chemical thinking and compatible with a classical (in the sense of pre-quantum) approach. Many chemists employ quantum-like terms, and rely on concepts that look quantum, such as ‘orbital’, but they actually play on the well-known ground of the classical structural ideas that can be traced back to the work of pioneers like Cannizaro, Kekulé, or van't Hoff. We maintain that given the fundamental role of these semi-classical ideas in chemistry, it is nothing but natural to treat them in an equivalent fashion in chemical education.

This mixed method study mainly explored how the extent of pre-service chemistry teachers' understanding of the particle nature of matter (PNM) affects their understanding of solution chemistry in the context of multirepresentational (MR) instruction. The ultimate goal was to describe the levels of understanding of specific solution chemistry concepts of a group of participants with a high understanding of the PNM and a group with a low understanding of the PNM before and immediately after MR instruction. Data sources included questionnaires about the PNM and interviews on solution chemistry. Data from these sources were coded and analyzed using quantitative and qualitative methods. There was a statistically significant difference between the results obtained for the understanding of solution chemistry before MR instruction for participants with a high understanding of the PNM and those with a low understanding of the PNM. Both groups of participants exhibited substantial progress towards the scientific understanding of solution chemistry from pre- to post-instruction; however, the participants with a high understanding of the PNM still outperformed those with a low understanding of the PNM in terms of developing a more scientific conceptual understanding of the topic after the MR instruction. Moreover, when the participants were provided with an opportunity to view dynamic visual particulate representations of phenomena to support verbal representations, about two-thirds of the participants from both groups were able to develop a scientific understanding of dissolution regardless of the extent of their understanding of the PNM. Yet, the findings suggested that the participants with a high understanding of the PNM were more likely to develop a scientific understanding of a particular concept (e.g., supersaturated solutions) in solution chemistry even without viewing the available visual particulate representations of the phenomenon.

A significant body of the literature in science education examines students' conceptions of the dissolution of ionic solids in water, often showing that students lack proper understanding of the particulate nature of dissolving materials as well as holding numerous misconceptions about the dissolution process. Consequently, chemical educators have explored several instructional strategies to address this issue including the use of multimedia, computer animations, and hands-on activities. In this paper, we describe the ways in which the use of physical 3D magnetic molecular models during a cooperative inquiry-based activity on chemical bonding prompted classroom discourse on what counts as chemically justifiable and appropriate representations of dissolved ionic solids in water. In so doing, we use the intersection of science education and technology to research the role of models in science teaching, the nature of classroom discourse initiated by modeling activities, and unfolding changes in student conceptions and ultimately student learning.

If the goal of teaching is to help students understand a subject, teaching cannot begin until student difficulties with a subject are understood. In order to create a guide for assessing student difficulties with chemistry material, students were asked to rate exam questions on three factors: problem difficulty, familiarity, and self-confidence. These surveys were then compared to difficulty ratings of the same questions as determined by chemistry professors. Students' ratings of problem difficulty, problem familiarity, and self-confidence correlated, as expected, with their success on exam problems. There was also some agreement between students and faculty on the difficulty of exam problems, though students were much more accurate of judging problem difficulty than were chemistry professors. Students were surveyed in two separate cohorts to test year-to-year reliability.

Most undergraduate chemistry courses and a few high school honors courses, which focus on physical chemistry and quantum mechanics, are highly mathematically-oriented. At the Technion, Israel Institute of Technology, we developed a new module for high school students, titledChemistry – From “the Hole” to “the Whole”: From the Nanoscale to Microelectronics. The module is based on a qualitative approach to teaching quantum chemistry, emphasizing interdisciplinary real-life applications and integration of visualization. While aimed at honors high school chemistry students, the module was also partially implemented and assessed in an undergraduate chemistry course. The research objective was to investigate the effect of the module on the visual and textual understanding of quantum mechanical concepts among 122 honors and 65 volunteer undergraduate chemistry students. The research tools included students' pre- and post-questionnaires. High school honors and undergraduate students, who were exposed to the module, significantly improved their textual and visual understanding of quantum mechanical concepts and their ability to move across illustrations and explanations. Honors and undergraduate students minimized the gap that had existed between them in terms of integrating micro and quantum levels into their post-questionnaire answers. Our findings augment the current set of the four chemistry understanding levels – macro, micro, symbol and process – by adding the quantum mechanical level as a fifth level of chemistry understanding. The study contributes to teaching physical chemistry by providing a tool for learning, assessment, and research of chemistry understandingviaboth visual and textual modes.

This paper presents findings from a content analysis of 650 empirical chemistry education research papers published in two top-tiered chemistry education journals Chemistry Education Research and Practice and Journal of Chemical Education, and four top-tiered science education journals International Journal of Science Education, Journal of Research in Science Teaching, Research in Science Teaching and Science Education from 2004–2013. We found that empirical chemistry education research (CER) papers accounted for 7.7 percent of the publications in the four science education journals. The most highly published area of research was in conceptions and conceptual change and most studies adopted mixed methods. The majority of the studies were conducted in higher education contexts and in the United States. Researchers who publish prolifically in the field included Vicente Talanquer, Derek Cheung, Michael Sanger, Keith Taber, Melanie Cooper and Marcy Towns. Current research trends and gaps are illuminated and possible future work in CER is discussed in the paper.

We studied how students engaged with an interactive simulation in a classroom setting and how that engagement was affected by the design of a guiding activity. Students (n = 210) completed a written activity using an interactive simulation in second semester undergraduate general chemistry recitations. The same simulation – PhET Interactive Simulations' Acid–Base Solutions – was used with three written activities, designated as Heavy Guidance (HG), Moderate Guidance (MG), or Light Guidance (LG). We collected mouse click data and classroom field notes to assess student engagement with each type of activity. Simulation features were characterized as “prompted” or “exploratory” based on the presence or absence of explicit guidance in the written activity to use that feature. While students in every condition were engaged with the simulation and their activity, student interaction with “exploratory” features decreased significantly when more guidance was provided (LG = 85%, MG = 68%, HG = 9%, p < 0.0005). Lighter guidance groups explored more and attended to their simulation interactions, indicated by a redraw task in the week after use. These results indicate that activity design – in terms of guidance level – can strongly influence student exploration with an interactive simulation. We discuss the implications of these results for the design of activities to accompany simulations, including how to increase student practice in scientific inquiry.