Mental Floss

Students Invent a Fire Extinguisher That Uses Sound

Rebecca OConnell

Scientists have used sound to do all kinds of amazing things, from levitation to brain surgery. Now, they've shown that sound can be used to put out fires.

Students Seth Robertson and Viet Tran from George Mason University have developed a way to harness sound and use it as a fire extinguisher. Low frequency sound waves—similar to the deep bass often found in hip-hop music—can apparently displace oxygen. If the oxygen is pushed away from the fuel, the fire will starve and go out.

The team started their endeavor after learning that sound had the ability to disrupt flames. They did not hear of any products on the market that worked, so they sought to make their own. Robertson and Tram originally experimented with high frequency sound between 20,000 and 30,000 hertz, but they found that 30 to 60 hertz was the ideal range. The students also learned to avoid music because the sounds were not consistent enough.

The resulting invention is a portable device that works similarly to a traditional extinguisher. A frequency generator was plugged into a power source and a cardboard tube then channeled the sound into a localized place. By pointing at the fire with the new invention, the flames dispersed, seemingly by magic.

This could do some serious good—not just on Earth, but also in outer space. "Fire is a huge issue in space," said Tran in a release. "In space, extinguisher contents spread all over. But you can direct sound waves without gravity," explained Robertson. The lack of foam is also perfect for outdoor settings or small rooms where the extra mess wouldn’t make sense.

The project has a lot of potential, but is not yet patented. “We still want to do a lot more testing," Tran said.

Kenneth E. Isman, a clinical professor at the University of Maryland, told the Washington Post that the invention still had some limitations. “One of the problems with sound waves is that they do not cool the fuel,” Isman said. “So even if you get the fire out, it will rekindle if you don’t either take away the fuel or cool it.”