Journal of Chemical Education最新文献

Student engagement in evidence-based argumentation plays a central role in science education. These skills can be developed when identifying organic molecules from the spectroscopic data. Molecular structural analysis fosters deep procedural knowledge, as it involves (i) flexibly applying a set of procedures to extract information from spectra, (ii) using this evidence to shape a claim about the unknown structure, and (iii) ensuring that the tentative claim aligns with all gathered evidence. In this study, we analyzed how successful first-year undergraduate students are in using procedural resources in the context of mass spectrometry, infrared spectroscopy, and nuclear magnetic resonance including one-dimensional ¹H NMR and ¹³C NMR and two-dimensional ¹H–¹³C HSQC spectroscopy. We identified a set of resources that have been successfully deployed by students. The interpretation of ¹H–¹³C HSQC spectra is one of these well-performed tasks. Binary logistic regression led us to conclude that the correct use of ¹H–¹³C HSQC correlations was significantly associated with the students’ success in finding the evidence-based structure as it increased the odds of identifying the unknown compound by a factor of 21.5. This technique was found to be a valuable tool, especially for novice students who are less efficient in finding relevant information compared to expert students. We therefore recommend including the basics of ¹H–¹³C HSQC NMR in the set of spectroscopic techniques taught in undergraduate organic chemistry courses. In addition to helping students identify organic compounds, this can enable instructors to highlight students’ inappropriate assumptions and heuristics.

Contact electrification (CE) between hydrophobic polymers and water is a captivating phenomenon with practical applications in energy harvesting, sensing, and catalysis. This process involves charge transfer at the interface during solid–liquid contact electrification, enabling applications such as triboelectric nanogenerators and humidity sensors. To introduce this concept into the undergraduate classroom, we have developed two hands-on experiments. The first experiment involves a droplet nanogenerator, where students assemble the generator and power a commercial light-emitting diode (LED), exploring the application of solid–liquid contact electrification in converting mechanical energy into electrical energy. Additionally, we designed an integrated experiment that applies the principles of solid–liquid contact electrification to catalysis, specifically in the emerging field of contact-electro-catalysis (CEC). By integrating CE-driven hydrogen peroxide production with luminol chemiluminescence, this interdisciplinary experiment bridges concepts from contact electrification, sonochemistry, and chemiluminescence. This experiment offers students a valuable opportunity to bridge theoretical concepts with hands-on laboratory work, deepening their understanding of fundamental chemistry principles through an engaging exploration of energy conversion, catalysis, and chemiluminescence.

For decades, finding ways to improve student success in organic chemistry courses has attracted the attention of educators, researchers and administrators. Considering the abundance of literature describing evidence-based practices for effective organic chemistry instruction, deciding on which practices to implement can be unsystematic and overwhelming for change agents. In this study, we propose an approach to identify instructional practices with promise of success using student and faculty perceptions. Five organic chemistry faculty members were asked, through semistructured interviews, to share their experiences teaching organic chemistry courses. Based on the faculty interviews, an online survey to probe organic chemistry students’ experiences was created and administered. Following the survey, 14 organic chemistry students participated in semistructured interviews to gain insight into their survey responses. The interview transcripts were analyzed via Colaizzi’s phenomenological theming method. Comparative themes were generated that highlighted the key alignments and tensions between the student and faculty perspectives. There was a clear agreement between faculty and students that the amount of content and fast pace of organic chemistry courses is an element that makes the subject especially difficult. However, students and faculty disagreed concerning student use of resources and the student-instructor relationship in the course. Using these comparative themes, promising action items for the institution in the study include curricular reorganization, strategic emphasis of course resources, and interventions to improve student-instructor relationships. We propose this approach as a pragmatic way for faculty teams or change agents to select promising areas of evidence-based practices, providing direction for site-specific educational reform.

Goldenseal (Hydrastis canadensis L., Ranunculaceae) is a traditional North American herbal medicine with a long history of use to treat various illnesses, primarily as a chemotherapeutic agent for microbial infections. Two of its alkaloid constituents, berberine and (−)-β-hydrastine, have well-defined pharmacological effects. In addition to its presence in goldenseal, berberine (and analogues) are found in other plant families. One such is the barberry family (Berberidaceae), encompassing various medicinal and decorative species, including those of the genus Mahonia (Berberis). This 3-h laboratory practical has been devised to allow undergraduate students to isolate berberine and (−)-β-hydrastine from a commercially available root sample of goldenseal, and both berberine and the closely related alkaloid, jatrorrhizine, from the bark of Mahonia x media ‘Winter sun’. Isolation is carried out on a miniature, sustainable and environmentally friendly scale using flash column chromatography. A gradient mobile phase is utilized for the isolation of (−)-β-hydrastine and berberine from goldenseal. A notable feature of the isolation of berberine and jatrorrhizine from Mahonia is the utilization of silica gel loaded with 10% w/w sodium carbonate. In this way, jatrorrhizine, an acidic alkaloid, is significantly retained while berberine elutes effortlessly from the column. A follow-on spectral assignment workshop is undertaken using 1- and 2-D NMR and IR spectra of the isolated alkaloids. Both formative and summative assessment of student comprehension takes place during the practical, workshop and end-of-semester college examinations. The experiment has been fully validated in the class setting, having been completed by circa 160 third year pharmacy students.

Science practice (SP) proficiency is an important learning outcome of undergraduate chemistry laboratories. The eight science practices provide a framework to describe how students can improve their use of scientific processes, such as argumentation, in line with those of research scientists. A curriculum that intentionally elicits student development with the SPs is necessary to make meaningful progress with SPs. This study focuses on student engagement with science practices in the introductory chemistry laboratory. In particular, a comparison is made between the engagement with SPs in Argument Driven Inquiry (ADI) style and traditional experiments. The IONIC (ICAP to Measure by Observation NGSS Science Practice Implementation in the Classroom) observation rubric was used to assess students’ in-lab engagement with each of the SPs. Based on the current set of data, the ADI-modified laboratory style has yielded higher rubric scores than the traditional laboratory style across all groups observed, indicating increased student engagement with SPs in ADI laboratories.

The 21st century has witnessed significant technological advancements, leading to the development of the multimedia-supported flipped classroom approach. This innovative teaching method has shown potential in enhancing instructional strategies by fostering active student participation and improving academic achievement. Thus, this study explores students’ conceptual mastery and perspectives on the use of the multimedia-supported flipped classroom approach in organic chemistry. To achieve this, an explanatory sequential design was employed, starting with quantitative data collection and followed by qualitative data for deeper insights. Using purposive sampling, 128 senior five students from two secondary schools were selected, with 73 students in the experimental group and 55 in the control group. Stratified sampling was also used to select seven students and two chemistry teachers for interviews. Quantitative data from pre- and post-tests were analyzed using the Statistical Package for Social Sciences (SPSS), while interview data were analyzed thematically. The results showed a significant learning gain, with the experimental group achieving a 14.23% improvement compared to the control group’s 5.13%. The experimental group’s mean score increased from 22 (std dev = 5.07) to 33.1 (std dev = 4.10), while the control group’s mean rose from 22 (std dev = 7.39) to 26 (std dev = 6.92). While most students appreciated the approach, others encountered difficulties such as technological constraints and weak Internet connectivity, prompting the study to recommend improving technology support, boosting access to information and communication technology resources, and conducting proactive troubleshooting.

Chemistry instruction should provide students a rationale for appreciating chemistry as a useful discipline, which is a particular challenge given the diverse student interests within introductory chemistry courses. In this study, we introduce and evaluate an interactive assignment, called an Informative Utility Value Intervention (IUVI), meant to improve students’ perceptions of the utility of chemistry. IUVI provides students with web-based articles describing how chemistry topics are relevant to the students’ chosen career interests. IUVI was administered to second-semester general chemistry students with a quasi-experimental study design in which one section from each instructor was given the intervention, and pre-intervention measures were used to account for potential differences between groups. The results indicate that students who received the intervention reported higher perceptions of the utility of chemistry at the end of the semester and higher scores on a common final exam than students who did not receive the intervention. Results from a structural equation model indicated the IUVI was associated with improved utility perceptions and final exam scores; however, these improvements were potentially independent of each other. Therefore, the theoretical explanation that improved perceptions of utility value resulted in improved academic performance could not be supported. Overall, IUVI offers an effective and highly portable intervention which can be adopted and adapted by instructors to promote students’ utility perceptions of chemistry.

To understand student experiences in chemistry courses, it is vital to measure student attitudes and beliefs, as they relate to learning and the course. In recent General Chemistry courses, the University of Chicago embarked upon a course redesign initiative guided by three evidence-backed pillars: Active Learning, Accessibility, and Transparency. Updates to the existing sequence included reordering the course content, adoption of open-access materials and interactive online platforms, and standardization processes to add structure to assignments and grading. In an effort to investigate this implementation in relation to student course experience, a set of surveys focused on student motivational and affective factors were developed and administered to students in the academic years immediately pre- and post-redesign. In the year following course updates, students reported significantly higher self-efficacy in learning chemistry, value of learning chemistry in the classroom and beyond, and higher satisfaction with the skills and content learned in General Chemistry, compared to the cohort of students in the previous year who did not experience the redesigned course. The frequency of students’ reported changes to their major and/or career plans as a result of General Chemistry did not differ significantly between cohorts. Combining multiple pedagogical strategies that aim to increase the approachability of content, clarity of communication, and engagement in the learning process may be a promising approach related to strengthening student beliefs about their own abilities and the value of the content they are learning in their chemistry courses.

An acid–base titrator connected to the Internet was developed for conducting remote investigative experiments. The experiment was broadcasted in a high school senior classroom, with the presence of a facilitating teacher. The activity required students to determine the indicator present in the solution. To carry out the activity, students added acid or base to sweep the pH range from 0 to 14 and noted the corresponding coloration to the pH through video analysis. The results obtained were very satisfactory, both in the identification of the indicator and in the acceptance and engagement of the students in the activity.

Initially, students performed a qualitative analysis to detect the presence of oxidizing compounds in cow’s milk samples. This was achieved by observing the oxidation of potassium iodide (KI) by hydrogen peroxide (H₂O₂). Subsequently, the concentrations of H₂O₂ in the milk samples were quantified using images of 96-well plates captured with a flatbed scanner. This method is straightforward, efficient, and ideal for high-throughput analysis. The RGB values from the 96-well plates were automatically extracted using the ImageJ plugin, ReadPlate. For the quantitative analysis, students explored various figures of merit, including the limit of detection (LOD), limit of quantification (LOQ), linearity, sensitivity, and recovery. Milk samples were spiked with H₂O₂ at three concentrations (0.03%, 0.06%, and 0.09%), and the measured concentrations in these spiked samples were compared to evaluate interclass repeatability using one-way ANOVA. Post hoc tests, including Games-Howell and Tukey, were used to identify significant differences between concentrations across the classes. Before conducting the one-way ANOVA, students assessed data normality using Q-Q plots, the Shapiro–Wilk test, and the Anderson–Darling test. They also evaluated the homogeneity of variance with Levene’s and Bartlett’s tests. Additionally, a two-way ANOVA was employed to analyze the effects of spiking concentrations and laboratory classes on the recovery. This analysis revealed a significant interaction between spiking concentrations and laboratory classes on recovery. All statistical tests were conducted using accessible and user-friendly freeware, providing students with practical experience in both data analysis and statistical interpretation.