Building Chemistry Knowledge Through Images in Secondary School Chemistry Textbooks: A Legitimation Code Theory Perspective

This study explores the knowledge-building of chemistry through images in secondary school chemistry textbooks, focusing on their changing abstraction and complexity across learning stages. Drawing on Semantics in Legitimation Code Theory, this study analyzes how these images develop across learning stages to cumulatively build chemistry knowledge in terms of their changing semantic gravity and semantic density and shifts of semantic codes in semantic planes. The findings reveal two typical patterns for the development of semantic gravity and semantic density of these images: (1) throughout the knowledge-building process, semantic gravity continuously weakens, while semantic density keeps strengthening; (2) semantic gravity weakens initially and then stabilizes at a certain level, while semantic density keeps strengthening throughout. These patterns correspond with two semantic pathways in semantic planes, respectively: 1) from a prosaic code through a worldly code to a rhizomatic code; (2) from a prosaic code to a rhizomatic code and then to a more right-positioned rhizomatic code. The first semantic pathway allows the images to present a concrete and everyday phenomenon, then provide an abstract and technical explanation for this phenomenon at the microscopic level, and finally develop a more abstract and complex theoretical explanation at the symbolic level. The second semantic pathway enables images to transition directly from a concrete and everyday phenomenon to an abstract and technical explanation of this phenomenon at the symbolic level and further to a more complex theoretical explanation at the symbolic level.