Acoustic levitation results when a small object is placed into the node of a standing wave—an area where the acoustic pressure is almost zero. The technology enables scientists to work with materials that might crystallize or become contaminated upon contact with containers.
from Smarter Every Day
Key Facts In This Video
Two identical sound waves projecting in opposite directions can create a standing wave, which has neutral areas that don't oscillate. (1:22)
Acoustic levitation "floats" objects in the neutral areas of a standing wave. (1:43)
Water droplets undergoing acoustic levitation will explode when the amplitude of sound is increased beyond a certain threshold. (3:42)