While something called a "vortex gun" might sound like a device from science fiction, the fact is that they have been available as novelties for years - if you've ever used a toy gun that shot out a ...

Vortex guns are those thing-of-the-movies type guns which can fire doughnut-shaped rings of air. Vortex guns have stayed as toys and odd gadgets for years, until now. But a U.S. lab is recently ...