An analysis of changes in the representation of the Nature of Science in Japanese grade10–grade12 science textbooks

Background: With the growing emphasis on scientific literacy, the Nature of Science (NOS) has become a core objective of science education, and its representation in textbooks has received increasing attention. Purpose: This study aims to systematically examine the representation of NOS in Japanese high school science textbooks and explore differences across subjects and grade levels. It seeks to provide empirical evidence to inform curriculum reform and textbook development in the Asian context. Method: Using the NOS analysis framework proposed by Abd-El-Khalick et al. this study analyzes the 2023 editions of high school physics, chemistry, and biology textbooks published by Tokyo Shoseki. A comparative analysis was conducted on the frequency, distribution, and explicit/implicit modes of NOS representation in chapters related to lower (10th) and upper (11th and 12th) grades. Results: The analysis revealed a downward trend in both coverage and frequency of NOS representation in the upper grades, particularly in the ‘Creative’ and ‘Social and cultural embeddedness’ dimensions. The proportion of explicit representation varied by subject and content type, with physics and chemistry showing more explicit representation in lower grades, while upper-grade materials tended toward implicit, theory-oriented content. Despite the generally positive overall performance across textbooks, issues such as weakened goal orientation and reduced content systematization were observed in upper-grade materials. Conclusions: To enhance and deepen students’ understanding of NOS, textbook development should focus more on ensuring a spiral progression of NOS dimensions across grade levels and adopt a balanced strategy that combines explicit and implicit representations. The findings offer practical guidance for optimizing science textbooks and advancing curriculum reform efforts in the region.