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Can a guitar really blast you through a wall? We asked a physicist
By
Editorial Staff

Published

March 13, 2014

Genre

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by Dave Shumka

Remember back in the '80s when there was nothing cooler than an electric guitar, and it could do anything? Comedian Patton Oswalt says it best: "The one thing I really liked about the '80s hair band videos ... were the bands that rocked so f--king hard, they could change the physical properties of things!"

There were videos of shredding guitars smashing windows, launching people through roofs and deflecting bullets. Growing up at the time and knowing how cool guitars were, I just assumed it was all true. Now it seems a bit far-fetched.

So I decided to ask a theoretical physicist about some of my favourite movie and video guitar blasts, and whether I need to be worried that I might rock myself to death. Dr. Ben Tippett is a sessional instructor at the University of British Columbia's Okanagan campus and the host of the Titanium Physicists Podcast, which has featured guests like Ted Leo, Greg Proops and myself.

1. Marty McFly playing through Doc Brown's huge amp in Back to the Future.

Rock explanation: Marty plays one chord through the giant amp and is blown across the room, along with a bunch of papers. It can totally happen. That's why they're called "power chords," doi-oi-oi. Marty's totally fine, by the way.

Physics explanation: According to Tippett, sound waves are all about air pressure, and air pressure wants to be consistent in a room. The high pressure wave that blows Marty across the room would be followed by a low pressure wave that sucks him forward. Also, a sound blast this powerful would deafen him.

A speaker this size is capable of producing frequencies too low to hear, which would shake Marty a little bit — not knock him off his feet. Some engineering students tried to replicate this speaker with some bone-rattling results.

This real-life speaker produces frequencies as low as five hertz, which is in the range of the fabled, pants-ruining "brown note," or as Tippett suggests, "the Doc Brown note."

2. Macaulay Culkin smashing windows and blowing George Wendt through the roof in Michael Jackson's "Black or White" video.

Rock explanation: Culkin blasts a chord through his giant stereo speakers, smashing all the windows in the house. Then he wrenches on the whammy bar, which, as we all know, is the most badass thing you can do on a guitar. This sends Wendt (his dad? That seems weird) literally through the roof, and he eventually lands in Africa. Yeah! Screw you, dad!

Physics explanation: Tippett says it would take about 1,000 pascals of pressure difference to shatter windows, which is about as loud as a rocket launch. It's also well beyond the pain threshold, so Culkin would be clutching his ears before he even got to the whammy bar.

"Even the power of rock can't get rid of old guys in arm chairs," says Tippet.

3. This kid's powerful guitar blast pushing his drill sergeant dad through a window in Twisted Sister's "We're Not Gonna Take It" video.

Rock explanation: So badly does this kid wanna rock that even though he's not making a chord with his left hand or holding a pick in his right hand, his gentle strum causes his dad to tumble backwards through a window. Yeah! Screw you, dad!

Physics explanation: "Looks to me like the dad jumped," says Tippett. "That kid didn't even have a wall-sized amp. Also, the window didn't shatter like in the previous video."

4. Ted Nugent deflecting bullets with his guitar solo in Damn Yankees' "High Enough" video.

Rock explanation: So powerful is Nugent's guitar playing, combined with his sleeveless zebra duster, that bullets can't penetrate his skin. Either that, or he's hypnotized the police somehow, giving them Storm Trooper-like aim.

Physics explanation: "Bullets are really small and they're travelling really fast," says Tippett. "Whatever happens there needs to happen in a hundredth of a second." A quick calculation suggests Nugent needs to produce millions of pascals of pressure, like, say, a bomb exploding.

Tippett also points out that Nugent is producing this acoustic shield with an unamplified guitar. Although, even if there's an amp hidden behind him, the high and low pressure waves would push him towards the bullets and then suck them towards him.