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  1. Free, publicly-accessible full text available August 1, 2023
  2. Researchers have typically identified and characterized teachers’ knowledge bases ( e.g. , pedagogical content knowledge and subject matter knowledge) in an effort to improve enacted instructional strategies. As shown by the Refined Consensus Model (RCM), understanding teacher learning, beliefs, and practices is predicated on the interconnections of such knowledge bases. However, lesson planning (defined as the transformation of subject matter knowledge to enacted pedagogical content knowledge) remains underexplored despite its central position in the RCM. We aim to address this gap by developing a conceptual framework known as Pedagogical Chemistry Sensemaking (PedChemSense). PedChemSense theoretically expands upon the RCM that generates actionable guidelines to support chemsistry teachers’ lesson planning. We incorporate the constructs of sensemaking, Johnstone's triangle, and the models for perspective to provide a lesson-planning mechanism that is specific, accessible, and practical, respectively. Lesson examples from our own professional development contexts, the VisChem Institute, demonstrate the efficacy of PedChemSense. By leveraging teachers’ sensemaking of the limitations and utility of models, PedChemSense facilitates teachers’ designing for opportunities to advance their students’ chemistry conceptual understanding. Implications and recommendations for chemistry instruction and research at secondary and undergraduate levels are discussed.
  3. Free, publicly-accessible full text available June 1, 2023
  4. Within high school classrooms, chemistry teaching is generally not aligned with the Next Generation Science Standards. This could be attributed to the complexity of reasoning across different representational levels and the instructional challenges teachers face when communicating such information. To enhance high school teachers’ chemistry knowledge and instructional quality, our research consists of a professional development (PD) program. Known as the VisChem Institute (VCI), our program leverages the cognitive learning model and foregrounds sensemaking using molecular visualizations. The VCI positions teachers as learners of chemistry and of pedagogy as they initially storyboard phenomena at the molecular level and later create their own VisChem-inspired learning design activities. Prior PD research has typically evaluated participants’ conceptual understanding or pedagogical knowledge independently. Fewer studies, however, have qualitatively analyzed the relationships between artifacts produced by teachers as both learners of chemistry and of pedagogy to understand their overall experiences. Our exploratory investigation seeks to answer these research questions: (1) How do high school chemistry teachers’ storyboards and learning design activities change throughout the VCI? (2) To what extent and in what ways are high school chemistry teachers’ storyboards and learning design activities connected? Inductive and deductive coding of storyboards and activities incorporates principles frommore »model-based instruction and the cognitive learning model that informed the PD design. While early findings suggest that participants have improved the quality of their storyboards by including more details such as the influence of bulk water, epistemic practices of modeling require further analysis as evidenced by teachers’ learning design activities. Specifically, participants may view a VisChem visualization as a medium for knowledge transmission as opposed to a tool for student-centered sensemaking. Results and implications for PD and chemistry teaching will be presented.« less
  5. Bulk water is an essential component for dissolution-the process in which ionic compounds are broken down into constituent charged species. Water solvates ions, engages in hydrogen bonding, exerts electrostatic forces, and contributes to the effects of entropy and enthalpy. Despite bulk water’s importance, its submicroscopic presence is often omitted from high school instructors’ pedagogical practices. While the presence of bulk water may seem obvious to experts, such simplification may problematize novice learners’ sensemaking of aqueous reactions. This study thus investigates how the depiction of bulk water may affect a high school chemistry teacher’s ability to create comprehensive external representations of dissolution. Using phenomenography as our theoretical framework, we analyzed and compared dissolution representations produced by 19 teachers who were attending a four-day professional development program (PD). The results indicate that none of the representations had depicted the submicroscopic presence of bulk water while only two had indicated hydrogen bonding. As a result, these representations convey dissolution processes that are incomplete and/or scientifically inaccurate. Our findings suggest that the interactions of bulk water at the particulate level must be foregrounded in teacher learning. In this instance, less is not necessarily more. Simplification through omission, while appropriate in some contexts, carries themore »risk of fostering misconceptions of chemical phenomena. To ensure rigorous conceptual understanding at the student level, we must also foster chemistry understanding at the teacher level. This work has been relevant for my career as a pre-service teacher in that it has provided me with the opportunity to grow as both a learner and educator of chemistry. In this project, I had the opportunity to analyze chemistry teachers’ external representations of the chemical process of dissolution with respect to the depiction of bulk water.« less
  6. Pedagogical discontentment shows promise as a means for driving change in teaching practices, but this theory is currently under used in professional development programs. In a state of pedagogical discontentment, a teacher would experience dissatisfaction with the level of congruence between their beliefs and practices in the classroom. If negative student outcomes are observed as a result of this incongruence, this dissatisfaction would prime the teacher to change their practices in the classroom. In preparation for a professional development program in the summer of 2020, we developed and delivered a molecular-level content survey to participating teachers and their students that aimed to generate pedagogical discontentment. In this survey, students and teachers were asked to correctly answer 21 multiple-choice questions regarding molecular-level content. Additionally, teachers were asked to predict how their students would respond to each question. This survey was coupled with a largely unstructured prompt for participating teachers to reflect on their students’ performance, as well as the accuracy of their own predictions of student responses. In this presentation we will describe evidence of discontentment from teacher reflections and discuss proposed improvements to subsequent years of implementation of this portion of our work. Results have implications for teacher professional developmentmore »and the application of pedagogical discontentment theory to studies in chemistry education.« less
  7. Elevated rates of evolution in reproductive proteins are commonly observed in animal species, and are thought to be driven by the action of sexual selection and sexual conflict acting specifically on reproductive traits. Whether similar patterns are broadly observed in other biological groups is equivocal. Here, we examine patterns of protein divergence among wild tomato species ( Solanum section Lycopersicon ), to understand forces shaping the evolution of reproductive genes in this diverse, rapidly evolving plant clade. By comparing rates of molecular evolution among loci expressed in reproductive and non-reproductive tissues, our aims were to test if: (a) reproductive-specific loci evolve more rapidly, on average, than non-reproductive loci; (b) ‘male’-specific loci evolve at different rates than ‘female’-specific loci; (c) genes expressed exclusively in gametophytic (haploid) tissue evolve differently from genes expressed in sporophytic (diploid) tissue or in both tissue types; and (d) mating system variation (a potential proxy for the expected strength of sexual selection and/or sexual conflict) affects patterns of protein evolution. We observed elevated evolutionary rates in reproductive proteins. However, this pattern was most evident for female- rather than male-specific loci, both broadly and for individual loci inferred to be positively selected. These elevated rates might be facilitatedmore »by greater tissue-specificity of reproductive proteins, as faster rates were also associated with more narrow expression domains. In contrast, we found little evidence that evolutionary rates are consistently different in loci experiencing haploid selection (gametophytic-exclusive loci), or in lineages with quantitatively different mating systems. Overall while reproductive protein evolution is generally elevated in this diverse plant group, some specific patterns of evolution are more complex than those reported in other (largely animal) systems, and include a more prominent role for female-specific loci among adaptively evolving genes.« less
  8. COVID-19 is not only an obstacle which educators must surmount but also a source that further exacerbates the difficulties educators already face. For example, the literature has shown that isolation (i.e., one person teaching chemistry within a single high school) is an enduring difficulty educators experience. We fear that the pandemic has magnified high school teachers’ struggles, resulting in further siloing and the inhibiting of collegial interactions, access to professional development (PD) opportunities, and instructional reform. Our work aims to support high school teachers by redesigning a face-to-face PD program to one that is remotely-delivered. Our reflections of our PD’s transformation highlight the importance of conceptualizing theory-informed design principles for effective teaching and learning first, then modifying the delivery with appropriate tools and technologies. Namely, because our PD program leverages the cognitive learning model, we had to reconsider ways to more effectively prime the perception filter, reduce cognitive load, and link new ideas to prior knowledge for effective teacher learning of both chemistry and pedagogy in online/remote settings. We subsequently discuss the strengths, areas for improvement, and insights based on our experiences and our participants’ mid-institute feedback. We hope our rationales for how and why the VCI had been redesignedmore »inspire fellow teacher educators to explore new ways of maximizing teachers’ access to high-quality PD and mitigating the enduring challenges they face.« less