Abstract: The objectives of this research are to improve (1) the conceptual understanding on Simple Machines and (2) the learning activities. This research used the classroom action research with 2 cycles. Each cycle consisted of four phases, namely: planning, implementation, observation, and reflection. The subjects of the research were the class teacher of Grade V and the students in Grade V of State Primary School Buluspesantren, Kebumen as many as 25 students. The sources of the data of the research were the students, the teacher, the prevailing related documents, and the on-going learning process. The data of the research were gathered through in-depth interview, observation, test, and documentation. The data were validated by using data source and data gathering technique triangulations. They were then analyzed by using the descriptive comparative statistical technique of analysis and the interactive technique of analysis. The conclusions are the application of Quantum Teaching by optimizing the realia learning media can improve (1) the conceptual understanding on Simple Machines , (2) the learning activities. Abstrak: Tujuan penelitian ini adalah (1) meningkatkan pemahaman konsep pesawat sederhana, (2) meningkatkan aktivitas belajar siswa. Penelitian dilaksanakan dalam dua siklus. Setiap siklus terdiri dari perencanaan, pelaksanaan tindakan, observasi, dan refleksi. Subjek penelitiannya adalah guru kelas V dan siswa kelas V SD Negeri Buluspesantren, Kebumen yang berjumlah 25 siswa. Sumber data berasal dari siswa, guru, dokumen, dan proses KBM. Teknik pengumpulan data adalah dengan wawancara, observasi, tes, dan dokumentasi. Validitas data menggunakan triangulasi sumber dan triangulasi teknik. Analisis data menggunakan teknik analisis statistik deskriptif komparatif dan analisis interaktif. Simpulan dari penelitian ini adalah penerapan Quantum Teaching dengan mengoptimalkan media realia dapat (1) meningkatkan pemahaman konsep pesawat sederhana, (2) meningkatkan aktivitas belajar siswa pada pembelajaran IPA materi pesawat sederhana. Kata kunci: Quantum Teaching, media realia, pemahaman konsep pesawat sederhana, aktivitas belajar
