Development and Usability of RETEPI: An Augmented Reality Module on Image Formation by Spherical Mirrors for Form 4 Physics

This study focuses on the development and usability study of Realiti Terimbuh Pembentukan Imej Cermin Sfera (RETEPI), an Augmented Reality (AR) learning tool designed to assist Form 4 Physics students in visualizing the complex concepts of Image Formation by Spherical Mirrors. Geometric optics is traditionally challenging due to its reliance on abstract, two-dimensional textbook diagrams that often lead to student misconceptions. To address this, a developmental research design was employed, guided by the ADDIE model, utilizing the MAKAR XR platform to transition static diagrams into interactive 3D learning experiences. The research population comprised 108 Form 4 students, of whom 30 were selected through convenience sampling to participate in the field study, while 15 participated in a preliminary pilot study. Expert validation by two experienced Physics teachers demonstrated a high average validity level of 98%, indicating strong expert agreement on the tool's content accuracy and pedagogical suitability. The pilot study confirmed excellent instrument reliability with a Cronbach's Alpha of 0.905. The field study assessed the tool’s usability across three constructs: perceived product usefulness, ease of use, and satisfaction. Quantitative analysis revealed a high overall mean usability score of 4.28 (SD = 0.709), indicating highly positive student feedback. Specifically, the constructs of usefulness (mean = 4.21), ease of use (mean = 4.31), and satisfaction (mean = 4.31) scored exceptionally well. These findings suggest that students perceive RETEPI as an engaging, user-friendly mobile learning tool that effectively supports their conceptual understanding and simplifies complex optical phenomena. Ultimately, RETEPI serves as a highly promising digital intervention that successfully bridges the gap between abstract physics theory and experiential learning.