Experiments in sound or acoustic levitation are common and ongoing. Dozens of researchers have managed to use sound waves to levitate and move tiny particles and liquid droplets. Multiple vibrating plates are used to create different frequencies and move an acoustic field with particles trapped inside.
The techniques developed have not been used to lift heavy or large objects. Twenty-first century scientists do not yet know if such a thing is possible.
But there have been breakthroughs, some of which are significant enough to suggest that large-scale acoustic levitation may some day be possible.
Floating on a Wave of Sound
In two experiments, scientist have successfully levitated lightweight polystyrene balls greater in size than the wavelengths used to elevate them, which represents an important step forward in the management of the force of concentrated sound.
One of these experiments, carried out by a joint team of researchers in the UK and Brazil in 2016, lifted a 50-millimeter polystyrene ball several centimeters off the ground, where it remained suspended for as long as the sound waves were generated. Just one year later, another group of researchers working out of the University of Bristol successfully levitated a polystyrene ball of two centimeters in diameter.
These experiments might seem redundant. But researchers used two entirely different methods for achieving this feat.