Researchers have been trying for decades to trap objects using only the power of sound but it has always proved impossible to hold an item steady if it was larger than the wavelength of the sound.

A 2cm ball hovered without moving CREDIT: UNIVERSITY OF BRISTOL 

Objects inevitably ended up spinning uncontrollably and eventually shooting away from the beams, after picking up the movement of the rotating sound field.

But now engineers from the University of Bristol say they have solved the problem. Instead of using a spinning field of sound to hold an object in place, they have built a device which turns to soundwaves into mini tornadoes.