> at room temperature the average velocity of a particle is a staggering 460 m/s so to make the particles visible I’m showing their motion significantly slowed

> at room temperature the average velocity of a particle is a staggering 460 m/s so to make the particles visible I’m showing their motion significantly slowed down Isn't 460 m/s the speed of the shock waves? I mean, it you make some "air particle" move, it'll hit a nearby particle, and so on, and this wave has a speed of 460 m/s. In a solid object (wood, for example) the particles are close together and the speed will be greater. If you remove air particles it'll decrease the pressure and the speed will be slower...