EFFECTIVENESS SCIENCE LEARNING INNOVATION THROUGH ANDROID-BASED LEARNING MEDIA AND WATER PURIFICATION PRACTICE WITH PROBLEM-BASED LEARNING MODELS. SPEKTRA [Internet]. 2024 Apr. 30 [cited 2026 May 28];10(1):1-14. Available from: https://ojs.unsiq.ac.id/index.php/spektra/article/view/11086