IMPROVEMENT OF STUDENTS’ SCIENCE PROCESS SKILLS IN SCAFFOLDING-BASED PROBLEM BASED LEARNING ON THE MATERIAL OF TRAVELLING WAVES AND STATIONARY WAVES. SPEKTRA [Internet]. 2026 Mar. 9 [cited 2026 May 28];11(1):49-61. Available from: https://ojs.unsiq.ac.id/index.php/spektra/article/view/7812