Abstract
This action research explores the effectiveness of collaborative teaching in enhancing senior students’ argumentation skills through integrated Science and Global Perspectives lessons. The intervention combines the BSCS 5E Instructional Model with individualized instruction to foster critical thinking, reasoning, and evidence-based discourse. Conducted over two action research cycles, data were collected through classroom observations, student questionnaires, reflective journals, and analysis of students’ argumentation using the Claim–Evidence–Reasoning framework. Findings indicate significant improvement in students’ ability to construct well-supported arguments, engage in critical discussions, and apply reasoning across interdisciplinary contexts. Beyond academic performance, students demonstrated increased confidence in expressing ideas, effective teamwork, and a greater appreciation for multiple perspectives. The study concludes that collaborative teaching, supported by 5E lessons and individualized tasks, enhances student-centered learning, inclusivity, and essential 21st-century skills. Implications for curriculum design and teacher professional development are discussed, providing guidance for scaling this approach in diverse educational settings.