Acoustic Levitation: The Floating Skull (3D)

Ultrasonic acoustic levitators trap small, light objects in mid-air using nothing but sound: two opposing transducers set up a resonant standing wave, and the acoustic radiation force pushes anything sufficiently small and dense toward the wave's pressure nodes. This 3D simulator renders a real standing wave between an emitter and a reflector — tuned to a whole number of half-wavelengths for resonance, with node spacing set by the true relation λ = c/f — and integrates a small floating skull's motion under the acoustic trapping force, gravity, and air drag. Drag the skull off its node to see the restoring force pull it back, or turn the drive amplitude down until the trap can no longer support its weight.