The video that accompanies this page has been produced by “Argonne Labs” and demonstrates the ability to levitate small objects with fluids and sound waves produced by two small speakers with frequencies above 20 KHz (22.000 Hertz)
The two loudspeakers, aligned with high precision, generate some points in space ,called nodes, in which there is no energy transfer; the pressure of the sound waves is able to counteract the force of gravity allowing the drop to remain in suspension. An interesting effect developed by NASA to simulate microgravity and can be used at present for the synthesis of drugs.