Subscribe
Science Notebook

How to put out a fire using nothing but bass (+video)

Two George Mason University students built a fire extinguisher that can put out a blaze without using water, foam, or chemicals. The device emits a low-frequency hum that deprives the fire of oxygen.

  • close
    Two George Mason University engineering students built a fire extinguisher that uses sound waves to choke out flames.
    View Caption
  • About video ads
    View Caption
of

Firefighters use water or chemicals to put out fires, but two engineering students at George Mason University have shown that it’s possible to extinguish a blaze using nothing but sound. Seth Robertson and Viet Tran built a device that looks like a traditional fire extinguisher connected to a power unit the size of a small messenger bag, that uses booming bass notes to snuff out flames.

The video shows Mr. Robertson aiming the extinguisher at a small fire lit in a kitchen skillet. As the device emits a low hum, the flames waver briefly and almost immediately vanish – no water, chemicals, or foam needed.

How does it work? As music notes get deeper, the amount of air required to produce them increases. That’s why bass guitarists need big speakers to amplify the notes their instruments create. A deep tone is essentially a blast of air, and the deep hum created by Robertson’s and Mr. Tran’s invention is essentially a regular series of these blasts. The flames are extinguished just as if somebody blew them out.

Recommended: The 20 most fascinating accidental inventions

Why not simply blow out a blaze using an air compressor or similar device instead of employing an audible hum? It turns out that sound waves displace oxygen in a particular way, depriving fire of the air it needs to survive. Robertson and Tran found that a tones at higher frequencies caused flames to vibrate, but that deeper tones in the range of 30 to 60 hertz kept flames from getting oxygen.

The Defense Advanced Research Projects Agency (DARPA) built a similar device in 2012, but didn’t pursue the idea of extinguishing fire with sound. DARPA’s device is large and unwieldy, while Robertson’s and Tran’s is portable. It consists of an amplifier and a loudspeaker positioned at one end of a cardboard tube, which allows the user to point the sound waves in a certain direction. George Mason University is helping the two students secure a provisional patent for their device.

Would a fire extinguisher that uses sound be useful in everyday situations? Robertson and Tran think it could be used in households – perhaps mounted over a stove to automatically extinguish grease fires. Robertson also speculated to CNN that astronauts could use the device to put out blazes in space. Sound waves aren’t affected by gravity, he says, so they could be directed at a fire more easily than conventional chemicals.

The students still need to do more testing to see whether their device works on different types of fires, and whether it can keep a blaze from spontaneously reigniting. They’ve already begun working to secure a provisional patent on the unconventional extinguisher.

About these ads
Sponsored Content by LockerDome
 
 
Make a Difference
Inspired? Here are some ways to make a difference on this issue.
FREE Newsletters
Get the Monitor stories you care about delivered to your inbox.
 

We want to hear, did we miss an angle we should have covered? Should we come back to this topic? Or just give us a rating for this story. We want to hear from you.

Loading...

Loading...

Loading...

Save for later

Save
Cancel

Saved ( of items)

This item has been saved to read later from any device.
Access saved items through your user name at the top of the page.

View Saved Items

OK

Failed to save

You reached the limit of 20 saved items.
Please visit following link to manage you saved items.

View Saved Items

OK

Failed to save

You have already saved this item.

View Saved Items

OK