Engagement and Achievement in Grade 9 Chemical Reactions: Classroom Demonstrations and Teacher-Curated AI-Assisted Representational Presentations

Abstract Chemical reactions require learners to coordinate visible phenomena, particle-level explanations, and symbolic equations. This quasi-experimental study compared two teacher-led approaches in a grade 9 chemical reactions unit: classroom demonstrations organized through prediction, observation, and explanation, and teacher-curated AI-assisted presentations that kept macroscopic, particulate, and symbolic representations visible during interpretation. The study examined a representationally scaffolded classroom format rather than an autonomous AI intervention. Participants were 120 students from four intact classes in one middle school and were classified pragmatically as typical or struggling learners according to prior science achievement. Both conditions addressed the same curriculum, lesson duration, teacher, and postunit measures. Outcomes included learning motivation, scientific curiosity, and chemistry achievement. The presentation condition produced higher scores, especially among struggling learners. Supplementary moderated mediation indicated that motivation and curiosity partially explained the association between instructional condition and achievement. The findings suggest that carefully reviewed visual sequences can support chemistry learning when they connect visible events, particle changes, and symbolic equations.