How the sonic 'tractor beam' levitates and manipulates objects
Key Excerpts from Article on Website of Christian Science Monitor
Posted: November 1st, 2015
It may seem straight out of "Star Trek," but it's real: Scientists have created a sonic "tractor beam" that can pull, push and pirouette objects that levitate in thin air. The sonic tractor beam relies on a precisely timed sequence of sound waves that create a region of low pressure that traps tiny objects that can then be manipulated solely by sound waves. Though the new demonstration was just a proof of concept, the same technique could be adapted to remotely manipulate cells inside the human body or target the release of medicine locked in acoustically activated drug capsules, said study co-author Bruce Drinkwater. The principle behind the new system is simple: Sound waves, which are waves of high and low pressure that travel through a medium such as air, produce force. "We've all experienced the force of sound," Drinkwater told Live Science. "It's a question of harnessing that force." By tightly orchestrating the release of these sound waves, it should be possible to create a region with low pressure that effectively counteracts gravity. Drinkwater, his Ph.D. student Asier Marzo and other colleagues ... found three different acoustic force fields. One works like tweezers and seems to grab the particles in thin air. Another traps the object in a high-pressure cage. The third type of force field acts a bit like a swirling tornado, with a rotating high-pressure field surrounding a low-pressure, quiet "eye" that holds the object in place.
Note: Watch a video of this incredible tractor beam in action.