Students Invent a Fire Extinguisher That Uses Sound

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.”

© 2017 USPS
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Speedy Delivery: Mister Rogers Will Get His Own Stamp in 2018
© 2017 USPS
© 2017 USPS

USPS 2018 Mister Rogers stamp
© 2017 USPS

After weeks of mailing out this year’s holiday cards, postage might be the last thing you want to think about. But the U.S. Postal Service has just given us a sneak peek at the many iconic people, places, and things that will be commemorated with their own stamps in 2018, and one in particular has us excited to send out a few birthday cards: Mister Rogers.

In celebration of the 50th anniversary of Mister Rogers’ Neighborhood, Fred Rogers’s groundbreaking PBS series that the USPS says “inspired and educated young viewers with warmth, sensitivity, and honesty,” the mail service shared a mockup of what the final stamp may look like. On it, Rogers—decked out in one of his trademark colorful cardigans (all of which were hand-knitted by his mom, by the way)—smiles for the camera alongside King Friday XIII, ruler of the Neighborhood of Make-Believe.

Though no official release date for Fred’s forever stamp has been given, Mister Rogers is just one of many legendary figures whose visages will grace a piece of postage in 2018. Singer/activist Lena Horne will be the 41st figure to appear as part of the USPS’s Black Heritage series, while former Beatle John Lennon will be the face of the newest Music Icons collection. Sally Ride, the first American woman in space, will also be honored.

Can You Spot the Christmas Pudding?

Whether it’s a sheep hanging out with Santa Claus or a panda bear hiding among some snowmen, regular Mental Floss readers know that hidden picture brainteasers are one of our favorite things. And the optical experts at have released a delicious one, just in time for Christmas. Somewhere in the midst of all these holiday-themed goodies above, there’s a holiday pudding just waiting to be discovered. Can you spot it? Your time starts … now.

If you give up, or are the kind of person who reads the last page of a book before the first one and just wants to know the answer, scroll down to see where it’s hiding.



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