DARPA (Defense Advanced Research Projects Agency) has developed a technique that extinguishes fire by using sound. And before you break out your stereo to full blast the next time your dinner catches on fire, let’s remember that this experiment was done in a controlled space with trained professionals.
In a video published on their website, two speakers are put on either side of a liquid fuel flame to demonstrate how this is done. As Wired explains, “The sound increases air velocity, which then thins the area of the flame where combustion occurs, known as the flame boundary. Once the boundary area is thinned, the flame is easier to extinguish.”
The Instant Fire Suppression project was launched to find new ways to stamp out flames in enclosed areas, like cockpits, ship holds and ground vehicles — where they're difficult to control. While the idea of manipulating fire goes back to the early 1900s, this is one of the first examples of extensive research in the area.