PHOTOSYNTHESIS IN PLANTS: INTEGRATION OF CONCEPT MAPS AND EXPERIMENTAL ACTIVITIES

Abstract

This article presents a classroom-tested methodology for teaching photosynthesis in lower secondary biology through the combined use of concept maps and experimental activities. The approach answers a persistent challenge: many students memorize definitions yet fail to explain the mechanistic relationships among light, chloroplasts, pigments, water splitting, carbon fixation, oxygen release, and starch synthesis. Grounded in conceptual change theory, knowledge integration, and formative assessment, the intervention sequences lessons so that concept maps externalize prior ideas and guide inquiry, while practicals generate empirical evidence that is immediately reconciled on revised maps. The design was implemented over three to four 45-minute lessons using accessible materials: iodine starch tests on variegated leaves, carbon dioxide indicators for exploring gas exchange, and a leaf-disk assay to visualize oxygen evolution under different light conditions. Results indicate significant gains in mechanistic understanding, a reduction of common misconceptions (for example, “oxygen comes from carbon dioxide,” “plants photosynthesize at night,” or “plant mass comes from soil”), and improved ability to transfer ideas to novel contexts such as aquatic plants or shaded habitats.