<![CDATA[IPAS (Natural and Social Sciences) learning in class V C at SD Negeri Mranggen 2 was predominantly delivered through the lecture method, utilizing visual media with worksheets (LKS) as the primary learning resource. Teachers need to employ innovative learning models and digital media to stimulate students' learning motivation, thereby increasing their activity and learning outcomes. To address this, the teacher created a learning innovation called the MASTER model (Masalah, Agregasi, Solusi proyek, Tampilkan, Evaluasi, Refleksi) combined with MeSSI (Media Site Simulasi Interaktif) and implemented it in the classroom. The purpose of this study is to describe the changes in learning activities and outcomes of class V C students at SDN Mranggen 2 during the 2025/2026 academic year on electrical circuits material by implementing the MASTER model assisted by MeSSI. This type of research is classroom action research, which consists of four stages: planning, acting, observing, and reflecting. The results of the learning implementation after applying the MASTER model assisted by MeSSI showed an increase in students' activities and learning outcomes on electrical circuits material. The data obtained indicated a shift toward excellent student activity. Learning outcomes also improved across all three aspects: the cognitive aspect showed an average normalized gain (N-gain) score increase of 0.88, categorized as high, with an average score of 96; the psychomotor aspect achieved the excellent category; and the affective aspect, specifically in the dimensions of creativity and collaboration, also achieved the excellent category.]]>
