This study aims to investigate the influence of result-centric narrative structures in textbooks on teachers' explanatory mechanisms and to analyze the effects of providing mechanism-centered explanatory tools on shifting teachers' perceptions. The research procedure followed a four-stage design, which involved analyzing the narrative structures of textbooks for "Matter and Energy"-a high school elective under the 2022 Revised National Curriculum-and diagnosing the initial explanatory mechanisms of ten in-service chemistry teachers. Subsequently, after providing educational materials on catalytic mechanisms, the changes in teachers' perceptions were analyzed. The results revealed that all four textbooks focused predominantly on result-centric descriptions, such as the reduction of activation energy, and visual representations centered on energy diagrams. This structure was found to be a cause for confining teachers' thinking to a phenomenological level. However, teachers who subsequently encountered qualitative mechanism-based explanatory tools re-envisioned them as essential cognitive scaffolding rather than an instructional burden, demonstrating a distinct epistemological shift from simple 'conclusion transmitters' to 'causal explainers' who reveal the underlying causes of phenomena. This study suggests that for teachers to grow as agents of scientific explanation, it is necessary to strengthen their capacity for causal explanation within teacher education programs. Furthermore, it proposes that institutional legitimacy for providing causal explanations should be granted to teachers by officially specifying the inclusion of mechanistic explanations of catalysis within the national curriculum and textbooks.
This study aims to explore how high school students understand dynamic equilibrium from a kinetic perspective in phase equilibrium contexts. To this end, a survey was administered to 92 students enrolled in Chemistry II at a general high school in Chungcheongnam-do, South Korea. The survey asked students to describe changes in evaporation and condensation rates, as well as the time required to reach equilibrium and the rates at equilibrium under conditions of temperature change. Students' responses were analyzed by categorizing response types and identifying patterns of reasoning. The results showed that students experienced greater difficulty in understanding evaporation rates and rates at equilibrium than condensation rates. In particular, the concept of evaporation rate was found to function as a threshold concept that drives integrative understanding of related kinetic concepts in students' kinetic understanding of dynamic equilibrium. In addition, many students showed a tendency to struggle with integratively considering the time to reach equilibrium and the rates at equilibrium when temperature changed. These findings suggest the need to explicitly address the concept of evaporation rate in teaching dynamic equilibrium and to emphasize an integrative kinetic approach to equilibrium shifts under temperature change, rather than treating each aspect as an isolated category.
This study analyzed teachers' noticing of high school student's problem-solving through the think-aloud method. Ten teachers with diverse backgrounds participated. Student problem-solving videos and worksheets were used during semi-structured interviews. The findings revealed that many teachers attended to the overall aspects of the understanding stage in students' problem-solving process. The teachers focused on student's recall of related concepts or laws where errors occurred, while only a few paid attention to setting of subgoals. In addition, although teachers attended to student's formulation of equations, only a few attended to the deriving physical quantities using alternative approaches. Teachers who did not consider the understanding stage relied on subjective reasoning and provided interpretations that lacked sufficient evidence, while their instructional responses to promote the identification of conditions and the setting of subgoals were generally superficial when suggested. In contrast, among the teachers who considered the understanding stage and distinguished student's problem-solving process into understanding and planning stages offered interpretations based on valid evidence and proposed instructional responses that linked the identified conditions and goals to the planning stage. Some teachers proposed instructional responses that synthesized the related concepts or laws necessary for problem-solving. Additionally, they connected formulating equations and calculation processes to their instructional responses. Based on these findings, we proposed ways to improve teachers' noticing of student's problem-solving process.
Volatile Organic Compounds (VOCs) are significant pollutants emitted during industrial processes, with their release continuously increasing due to rapid industrialization, posing critical threats to environmental quality and human health. Catalytic oxidation is regarded as one of the most effective methods for VOC removal due to its low cost and high elimination efficiency. In pursuit of safety, energy savings, cost-effectiveness, and environmental friendliness, extensive efforts have been devoted to developing efficient catalysts that leverage the synergistic effects of catalysts and reactive oxygen species (ROSs) by incorporating ozone molecules, thereby reducing the temperature required for VOC catalytic oxidation. Based on research into largescale treatment of industrial VOC waste gases, this study proposes an integrated adsorption-catalysis process system that balances cost and efficiency. Waste disposable bamboo chopsticks were recycled as precursors for carbon-based materials, and transition metal manganese oxides with different crystal phases were loaded onto the carbon substrate. The MnOx-BC composite with the highest catalytic activity was selected for the catalytic oxidation of recalcitrant industrial o-xylene.
This study compared entropy descriptions and inquiry-activity structures across Korean high school Chemistry II textbooks aligned with the 2009 revised curriculum, Matter and Energy textbooks aligned with the 2022 revised curriculum, and college-level general chemistry textbooks. We conducted a deductive content analysis with binary coding and frequency summaries, complemented by comparisons of representative passages. The analytic criteria addressed the placement of the disorder metaphor, the presentation and use of the system-surroundings perspective, the inclusion of statistical explanatory elements and thermodynamic definitions and their explicit linkage, and the types, contexts, and process elements of inquiry activities. The results showed that in the 2022 revised textbooks, where Gibbs free energy is not introduced, the selection and organization of explanatory elements and the use of the system-surroundings perspective varied across publishers, whereas the disorder metaphor persisted mainly in definitions and examples. Inquiry activities increased overall, but quantitative experiments and calculations decreased, shifting toward data interpretation, discussion, and project-based tasks. These patterns suggest that presenting explanatory elements as separate components without explicit connections may place greater demands on students as they transition to college general chemistry, where explanations are typically more integrated. Accordingly, we propose that textbook descriptions and task designs explicitly connect statistical and thermodynamic perspectives through system-surroundings reasoning and require students to apply these connections in justification tasks.
