Low-frequency sound waves in the 30 to 60 hertz range -- “the thump-thump bass in hip-hop" -- can actually separate oxygen from fuel,” Tran said, in a GMU news release.
“The pressure wave is going back and forth, and that stirs where the air is. That space is enough to keep the fire from reigniting,” Tran told the Washington Post.
This isn’t the first time that sound waves have been used to handle fire. Experiments and research stretch back to decades; in 2012, the Defense Advanced Research Projects Agency (DARPA) released a video depicting how a “wall of sound” could extinguish flames.
However, as New York Magazine notes, DARPA’s setup was both “bulky” and “impracticable.”
There’s “nothing on the market that works,” Robertson told the Post. For now, the students’ extinguisher has only been used to extinguish small fires that use rubbing alcohol as fuel, but they hope their innovation might one day be used for consumer or professional use.