Two engineering students at George Mason University in Fairfax, USA, have created an ingenious gadget which can extinguish a fire using nothing but sound.
Viet Tran and Seth Robertson developed the sound extinguisher based around the principle of the 'Goldilocks Zone' which -- at around 30 to 60 hertz -- can effectively deprive a fire of the oxygen it needs.
The sound waves move the oxygen away from the fire, cutting off its ability to burn. Of course the method isn't without its hurdles. For starters the sound extinguisher simply moves oxygen, it doesn't cool it, so you'll need to use it until the surrounding area and the fuel itself has cooled down enough that it won't just reignite.
This is a big step though, while DARPA has worked on prototypes in the past, this is the first time that a portable unit has been developed suggesting that it could now finally be a viable alternative to current extinguishers.