Abstract
Science learning in junior high school often faces challenges of diverse learning readiness and high cognitive load during learning activities, leading to low conceptual understanding of abstract topics such as temperature and heat. This research aims to develop an adaptive student worksheet based on Cognitive Load Theory (CLT) using the backward fading technique and evaluate its validity. The development followed the Borg & Gall Research and Development (R&D) model, comprising needs definition, prototype design, development, and expert validation. The design systematically scaffolds problem-solving across four distinct stages—from full worked examples, step-by-step fading, to fully independent practice—to optimize working memory capacity. Expert evaluations using Aiken’s V formula demonstrated high content validity across all fifteen indicators, with coefficient values ranging from 0.863 to 0.875. Furthermore, overall validation scores reached 95.00% from media experts and 97.75% from subject matter experts. These findings confirm that integrating the backward fading technique into adaptive student worksheets effectively decomposes complex mathematical procedures, minimizes extraneous cognitive load, and is highly feasible for physics instruction in junior high schools.