Journal of Chemical Education最新文献

In undergraduate science education, laboratory courses stand as essential cornerstones of experiential learning. Chemistry laboratory courses offer students unique hands-on experiences that bridge the gap between theoretical knowledge and practical application. The journey through the undergraduate chemistry curriculum is paved with a series of conceptual gateways known as threshold concepts that can dramatically shape a student's understanding and success. We identified the idea of intermolecular forces (IMFs) as a threshold concept to students' ability to link molecular structures, properties, and applications to real-world problems such as extraction and separation of compounds. The development of course-specific pedagogical tools can provide students with the scaffolding necessary for the transition from novice to expert-level disciplinary comprehension. This work presents the development process of a Threshold Concept Assessment Rubric (TCAR) based on Johnstone's triangle framework and discusses its application for evaluating students' progress in overcoming a threshold concept. The rubric is used in a 200-level multilayer laboratory course that is intentionally designed with intermolecular forces as the central theme. We analyze the role and structure of different questions to provide a holistic assessment of students' learning processes using sample assignments. Furthermore, we demonstrate how insights from statistical analyses can highlight areas in which students struggle to gain expert or exemplary-level understanding of IMFs. This rubric development approach can be applied to other threshold concepts.

Faculty development programs play a crucial role in enhancing learning by equipping educators with the necessary skills, knowledge, and pedagogical strategies to teach more effectively. One such program is the Promoting Active Learning in Analytical Chemistry (PALAC) workshop, which aimed to educate faculty on methods to create and use active learning course materials to support students during the process of learning. This research aimed to assess the design of classroom instructional materials generated by faculty that attended the PALAC workshops. The theories of Vygotsky's zone of proximal development and scaffolding were used as lenses to characterize the materials because they describe the benefits of providing support through the process of developing knowledge. The active learning materials were analyzed by assigning the cognitive levels of processing, as described by Marzano's taxonomy, to all questions asked across 134 in-class activities. The use of the cognitive levels of processing allowed the researchers to gauge the presence of scaffolding by tracking how the cognitive levels of processing changed from question to question across each in-class activity. The results from this study indicate that the majority of materials provide opportunities for students to engage with higher-order questions, but there is less evidence for the effective and consistent structuring of the materials. These results have implications for future faculty development programs, suggesting the need to allot more time for faculty to practice developing effective classroom materials. In conjunction, this work demonstrates the effective use of Marzano's taxonomy in assessing the cognitive structure of in-class activities.

Specifications Grading was implemented in a multisection upper-level analytical chemistry laboratory, the first reported for a full lab course redesign in the discipline or in an upper-level chemistry lab class. The primary goals of the redesign were (1) to assess student proficiency of three separate goals: techniques, data quality, and written communication, with three separate assignments, (2) to encourage growth across the semester, providing students the opportunity to show their improvement, and (3) to implement a clear grading system that emphasized equity across the multisection course. Mark distributions on assignments show an increase in students earning exemplary marks on first attempts as the semester progressed, indicating improvement not only within assignments but also across assignments. Student feedback surveys indicate high satisfaction with the grading scheme, with over 72% of survey respondents indicating they would like the grading scheme applied to other courses. Additionally, survey results demonstrate success in achieving the three goals, with students able to articulate the benefits associated with the priorities of the course structure. A particular focus was on the actionability and timeliness of instructor feedback, a hallmark of specifications grading, which students also highly rated. Teaching Assistant feedback indicated that, despite more time spent on grading, teaching satisfaction was higher compared to other courses. The use of regular student feedback to improve the course design is also discussed.

A previous article in this Journal focuses on “No-Mess” coloring products that utilize the chemical reaction between colorless leuco dyes and zinc ions, which act as Lewis acids ( J. Chem. Educ. 2022, 99 (6), 2364−2371). This reaction causes the leuco dyes to become colored. There are two main types of No-Mess marking systems. The first type includes markers containing leuco dyes that become colored upon contact with zinc ions embedded in marking paper. In the second type, the system is reversed. The markers contain zinc ions that activate leuco dyes embedded in the paper. These products offer new opportunities for guided and open inquiry-based investigations. This paper reports that solutions of zinc ions develop the color of leuco marker dyes to a degree comparable with commercial systems. While solutions of other metal ions also induce this color change, they do so to a lesser extent. Therefore, using zinc ion solutions allows for experiments and demonstrations with No-Mess marking products to be more visually stimulating than those previously reported.