Fire extinguishers may soon be a thing of the past: wave a magic electric wand at a flame and you can snuff it out in milliseconds, according to Dr Ludevico Cademartiri.
In a paper presented to the American Chemical Society, Cademartiri's Harvard University team reported that they had been able to extinguish an 18in flame merely by using an electrified metal wire.
The beam of electricity came from a 600 watt amplifier, about the same power as a car stereo system; so, the firefighter of the future would only need an ultra-portable power pack and wire rather than a cumbersome hose and large quantities of water or foam.
How does it work, though? It's based on the observation made some 200 years ago that electricity can change the shape of flames. Previous experiments involved direct current, or DC. But Cademartiri's team used oscillating AC voltage, and found that the effects were "completely different": the electrical field charges the carbon particles (or soot) generated by the fire, creating an organised "flow" of charged particles inside the flame that literally pushes the flame away from the fuel source, putting it out.
"Essentially, the [electrical field] separates the region that's hot and burning from the unburnt fuel, so that fuel will not continue to burn," says Kyle Bishop, a researcher who worked with the team.
Cademartiri thinks the method could be a more sophisticated way of putting out fires "than just throwing water at them". And he and his colleagues are looking at applications beyond firefighting: controlling flames at will in the combustion process could, for example, lead to far more efficient coal, oil and gas-fired energy production.
