Smoke rings from a toy gun don't do much more than entertain a child. But by giving them an electrical charge, a company called Battelle has discovered a way to make them more useful for firefighting and even crowd control.
Its new gun has a special cylinder on the end that creates vortex rings that leave the barrel at 140km/h, and travel for more than 45m at a speed of at least 96km/h. And by giving the particles that are emitted an electrical charge, they actually stick to their target on impact.
So firefighters could launch a charged vortex ring into a smoky room, which would cause the smoke particles to disperse and seek out the nearest grounded surface. Or, in a more disturbing application, riot police could fire rings of pepper spray from a distance, ensuring the painful payload would be delivered and would actually stick to the skin of the intended target. So the next time you see a mesmerizing smoke ring coming towards you, I'd suggest looking away just in case.