The "Sound Light Fluid" three in one demonstration system designed specifically for primary and secondary schools as well as science popularization venues takes 3 minutes for students to "see" that sound requires a medium and "hear" that vacuum cannot transmit sound. Students "see" the air being sucked away and "hear" the sound disappearing, completely avoiding the misunderstanding of "glass cover sound insulation". All metal base+tempered glass, resistant to drop impact; The key components are modularized, and the electric bell or fan can be replaced within 1 minute. Used for physics classes on "Sound Phenomena" in primary and secondary schools, interactive exhibition areas in science museums, and teaching skills training in normal universities.