Sakuragaoka Junior High School, Setagaya-ku, Tokyo, Japan

Abstract: This paper presents the development and implementation of an AI-Enhanced Three-Dimensional Assessment (AI-3DA) model for junior high school chemistry education, designed and validated by a classroom teacher at Sakuragaoka Junior High School in Tokyo. Departing from traditional assessment approaches that focus primarily on knowledge recall and procedural skills, the AI-3DA model evaluates student learning across three interconnected dimensions: conceptual understanding, scientific practice, and scientific attitude and thinking. Artificial intelligence serves as an "intelligent assessment partner" that enhances rather than replaces teacher judgment, providing automated analysis of descriptive responses, experimental reports, and classroom dialogue data. The model was implemented over a 10-week period with 92 Grade 8 students across three classes, focusing on the unit on chemical reactions and atoms/molecules. A mixed-methods approach was employed, combining quantitative assessment data with qualitative evidence from classroom observations, teacher journals, and student interviews. Results indicate statistically significant improvements across all three dimensions, with the largest gains observed in scientific practice (d=0.82) and conceptual understanding (d=0.76). Students also showed significant growth in scientific attitude and thinking, including increased curiosity, better question-asking skills, and more metacognitive awareness. The AI tools were found to save teachers approximately 40% of grading time while providing richer, more detailed assessment data. The study contributes to the growing Japanese literature on competency-based assessment and AI integration in science education, offering a practical, teacher-developed model aligned with the Japanese Course of Study's emphasis on developing "zisshitsu nouryoku" (competencies and abilities).

Keywords: three-dimensional assessment, AI in education, junior high school chemistry, competency-based evaluation, scientific practice, Japanese science education