Journal of Chemical Education最新文献

Water condensation plumes produced by the addition of iron powder to liquid nitrogen can be contaminated with small quantities of particulate matter. Variations on the plume demonstration, including those using noisemakers, are described to help minimize the release of particulates into the air.

In a technology-centric world, leveraging digital tools such as chatbots allows educators to engage students in ways that may be more accessible for both parties, particularly in large lecture classrooms. This report details the development of an interactive web-based chatbot to curate content for writing about chemistry in context. Students were assigned a 500-word paper where they discuss general chemistry concepts through the lens of a timely, sustainability-related topic, i.e., water footprint, carbon footprint, or embodied carbon. Discussed herein are the development of the decision tree, the chatbot’s components, and results from the initial implementation in a large lecture general chemistry classroom. Over 78% of the 347 enrolled students (271) used the chatbot over 350 times in the 3 weeks leading up to the assigned due date of the paper. Eighty-three percent of the interactions were captured for further analysis, which showed that 22% of students used the chatbot more than once. Forty-six percent of recorded interactions were used to aid students in developing or refining their idea for the assignment. The curated chatbot technology reported here for writing assignments in chemistry can be readily adapted to other aspects of coursework in chemistry.

Chemistry is a systems science that deals with complex-dynamic systems and systems thinking is an essential aspect of chemical practices. Thus, a systems thinking approach is needed in chemistry education for meaningful learning of the subject matter. Despite this necessity, systems thinking has not received sufficient attention in chemistry education where it is typically linked to the teaching of sustainability goals. Consequently, it is important to develop a framework for implementing systems thinking from a chemical perspective. This article analyzes the philosophy of chemistry and chemistry education literature and chemists’ reflections on chemical practice and argues that systems thinking is an indispensable aspect of our discipline through a cycle of (1) modeling systems, (2) prediction, and (3) retrospection. In light of this analysis, competence in chemical thinking and meaningful learning of chemistry is linked to systems thinking and a novice-expert continuum is defined in terms of systems thinking skills in chemistry. It is also discussed how systems thinking can be implemented in chemistry education by identifying and modeling key aspects of studied systems, in particular emergence mechanisms of systemic properties, and engaging students in modeling systems-prediction-retrospection cycles through compare-predict-observe-explain tasks that highlight the focused key aspects. This approach is exemplified in the context of atomic systems and their properties at the undergraduate level.

Studying biochemical pathways can be challenging. Frequently, students rely on rote memorization to memorize the steps in metabolic pathways instead of having a deeper understanding of their functions, the reactions involved, and the inter-relationship between different metabolic pathways. In our project, we developed various bite-sized e-learning modules to facilitate students’ learning of carbohydrate metabolism. These modules were presented using different methods, including animations, manga, and interactive exercises. Students spent less than 5 min completing each module to allow them to be more focused and engaged. Memory cues were used to improve students’ understanding of the chemical reactions involved and thus facilitated memorization. Additionally, the pathways of carbohydrate, protein, and nucleotide metabolism were grouped together in a metro map to facilitate knowledge integration. This representation enabled students to correlate pathways in carbohydrate metabolism to other metabolic pathways and to get an overview of how common metabolites were involved in multiple pathways.

Developing and exploring new tools to engage students in the learning process have been major foci of chemistry education research. Creative exercises are one such tool that has drawn increasing interest from researchers over the past decade. While studies have reported the impact of creative exercises on learning and types of student responses generated, how the students engage with these particular exercises has yet to be explored. This study seeks to fill this gap within the literature by exploring student approaches to the creative exercises, within the context of biochemistry, through semistructured, think-aloud interviews. Analysis of 10 participant interviews investigated how undergraduate biochemistry students actively and verbally engaged in creative exercises. Findings reveal the variation in how the participants approached the creative exercises as well as the role that the course modality played in shaping the student approaches.

A community-engaged learning experiment was developed for an introductory analytical chemistry course at the University of Toronto Scarborough in collaboration with Campus Farm. The experiment introduced students to the application of analytical techniques to studying environmental samples. More specifically, students investigated the potential of red clover to serve as a hyperaccumulator of lead (Pb) while learning about broader phytoremediation strategies. The experience spanned two lab periods, the first involving a site visit to learn about the land and collect plant and soil samples. This was followed by a guided extraction and analysis of Pb content, introducing students to topics such as acid digestion, separation, and flame atomic absorption spectroscopy. Student results were aggregated and shared, allowing them to assess and comment on the efficacy of red clover to serve as a hyperaccumulator of Pb contamination. Moreover, student results and analyses were shared with community partners at the Campus Farm, with the opportunity to provide year-over-year data to monitor and assess a sustainable approach to remediating contaminated soil. Survey results reveal students’ appreciation for learning how analytical chemistry can be applied to study real-world samples and, more specifically, how it can be applied toward soil remediation efforts. This experiment can be adapted to work with students within the laboratory component of a course to assess a variety of other metal contaminants or study the efficacy of other potential hyperaccumulators moving forward, with the broader intention of informing and supporting soil remediation strategies in collaboration with community partners.

Protein structure and function are important concepts in the biochemistry curriculum. A three-part CURE was developed to be used in an undergraduate biochemistry course that enhances student learning of these aspects in addition to practicing oral and written communication skills. Students used three protein–protein docking programs (PRISM, InterPred, and ZDOCK) to recreate known protein complexes and then compared the accuracy of the results of each program. This was accompanied by an individual written report and finalized by an oral group presentation to the class. The majority of feedback from students was positive, revealing that students found that the project helped them to apply the concepts learned in class and become more comfortable with scientific writing.

Hydrogels are soft water-rich materials with physical properties that can be easily tuned by modifying their network structure. For instance, increasing or decreasing the cross-linking density has a profound effect on their water absorption capabilities and mechanical strength. These physical changes are showcased in a new experiment for organic chemistry and polymer science teaching laboratories based on the practical green synthesis and characterization of lactose methacrylate derived hydrogels. Lactose, a disaccharide derived from dairy waste byproducts, is functionalized with photoreactive methacrylate groups using methacrylic anhydride. The resulting mixture is subsequently photoirradiated to generate a cross-linked hydrogel. Structure–property relationships are assessed through comparative studies of three hydrogels of varying compositions. Compression tests and swelling studies in different aqueous environments offer a guided-inquiry experience. Students determine a relationship between cross-linking density and the physical properties of the hydrogels. This experiment highlights the valorization of biomass and multiple green chemistry principles including use of renewable feedstocks, atom economy, energy efficiency, waste prevention, and water as a benign solvent. Learning outcomes for an organic chemistry laboratory course include introduction to disaccharide and cross-linked polymer structures, observable physical change dependency with cross-linking density, and laboratory methods for evaluating water absorption capacities. Objectives aligned with a polymer course are incorporating mechanical compression instrumentation, mechanistic understanding of light-induced free radical polymerizations, and an appreciation for the application of hydrogels to commercial products. Overall, the translation of a current literature publication to an inexpensive and versatile experiment engages students in a modern example of sustainable polymer chemistry.

The partitioning of a dye, Brooker’s merocyanine (MOED), between water and 1-octanol and between water and dichloromethane is strikingly visible because of the dye’s strong solvatochromism, which makes the colors of the two layers different. The color change makes it easy to see that the dye has moved from the organic layer to the water layer or vice versa. A simple comparison of the color of the organic layer to reference solutions makes it possible to estimate rough values of K_D, the distribution equilibrium constant.