This video is from the physics site Physclips: https://www.animations.physics.unsw.edu.au/ It uses flutes, clarinets – and crossbreeds! – to demonstrate standing waves and harmonics. Much more about physics and music here: https://newt.phys.unsw.edu.au/music/ And some of my music here: https://www.youtube.com/watch?v=ox18_1pxYjE