I can certainly help describe what such a piece of music might sound like and even suggest a structure for it - Light Airy piano melodies to start Creating a peaceful Happy base - A gentle Rhythmic acoustic guitar joins in Giving it a fun Laid-back vibe - Soft drum beats and light percussion keep the tempo lively but not overwhelming - Flute or light synth melodies weave in and out Adding a playful Whimsical touch - Maybe a subtle use of marimba or xylophone to add to the cheerful and serene atmosphere Here's a suggested structure for your 3-minute instrumental piece: 0:00 - 0:30: Intro with a light piano melody and gentle guitar strums 0:30 - 1:00: Drum beat kicks in softly Adding a steady rhythm along with the piano and guitar 1:00 - 1:30: Flute or synth melody joins Enhancing the playful atmosphere 1:30 - 2:00: Build a bit with marimba or xylophone adding a cheerful touch 2:00 - 2:30: Bridge section with a slight variation in melody or instrumentation Maintaining the tranquility 2:30 - 3:00: Return to initial themes Gently fading out with piano and guitar This structure should create a happy Fun Yet tranquil background sound that's appropriate and enjoyable for 16-year-olds in a classroom setting. Of course For a real piece of music This would need to be developed further by a composer or produced with the appropriate musical tools