Mike,

This is in regards to what you said about it "not being proven for a large structure." I just recently finished Physics 20 and we did some research on the Tacoma Narrows bridge (it`s somewhere in the USA) as part of our unit on harmonic systems. This bridge, in the late 1960`s (I think), collapsed because of this very principle we are talking about. The Tacoma Narrows bridge was built in a very windy environment, and one day, the conditions were perfect for disaster.

You see, the wind was blowing across the bridge at a near constant speed, therefore making it vibrate at a near constant frequency. The amplitude of the waves continued to get larger and larger, until the bridge was moving violently from side to side. The stress of the motion was too much for the bridge to handle, and it collapsed.

In light of what happened at the Tacoma Narrows bridge, all modern bridges are now built with frequency cancellation devices in order to prevent something like that from happening again.

As was recently proven in Mythbusters, you can break glass with an un-amplified human voice. I didn`t know it was possible myself. You can also collapse a bridge if its motion has the right frequency proportional to its size.

Thomas

it has been done jamie vanderra did it on go morning america and on mythbusters unamplified !!

I am a singer and i am wanting to break glass with my voice. At the moment the highest note I can reach with my voice is an octave below to C on the piano.

forget glass i watched this program on `sky one` ages ago called `brainiac science abuse` (sad, i know) and they produce low frequencies that could loosen the bowel muscles so people..you know... themselves.

Charlotte Church broke a glass on a TV program by just singing with the glass very close to her lips.

yes its very possible seen in this video http://thatvideosite.com/view/1042.html

Actually they did it on myth busters but they had to use a crazy pitch and a huge speaker....

"Mike,

This is in regards to what you said about it "not being proven for a large structure." I just recently finished Physics 20 and we did some research on the Tacoma Narrows bridge (it`s somewhere in the USA) as part of our unit on harmonic systems. This bridge, in the late 1960`s (I think), collapsed because of this very principle we are talking about. The Tacoma Narrows bridge was built in a very windy environment, and one day, the conditions were perfect for disaster.

You see, the wind was blowing across the bridge at a near constant speed, therefore making it vibrate at a near constant frequency. The amplitude of the waves continued to get larger and larger, until the bridge was moving violently from side to side. The stress of the motion was too much for the bridge to handle, and it collapsed.

In light of what happened at the Tacoma Narrows bridge, all modern bridges are now built with frequency cancellation devices in order to prevent something like that from happening again.

As was recently proven in Mythbusters, you can break glass with an un-amplified human voice. I didn`t know it was possible myself. You can also collapse a bridge if its motion has the right frequency proportional to its size.

Thomas"


I live by this bridge, and have to hear this story every time we go over it. :P

Re: "has anyone actually ever brocken glass and is it possible?"

I`ve done it many times, and no, it is not possible.

It is primarily a function of volume and I saw it done on Mythbusters (discovery channel).

Take a thin wine glass and hold it directly in front of your face. Place a straw in the glass and slide up the scale until the straw moves (about 80db should get the straw moving). That is the resonant frequency you need to sing in order to break the glass. It is now up to you to generate the 110 decibels to shatter it. You can cheat and amplify your voice if you want to see it shatter.

i play trumpet and sax and can scream on both high and loud enough to break wineglasses and some windows

Check out www.thevoiceconnection.com for information on Jaime Vendera and glass breaking. He is the man.

Yes it can be done because, like a lot of you, i saw it on myth busters. On a personal note, the guy who did that is from my hometown. His stepson is one year older than me in school.

quote:
<if you want to hurt a person with sound, go with low frequencies... they would do more dammage.... sound physics is awesome stuff>

Its true. Contrasound creates a vibration rather than sound,
and ppl hu feel it mostly get nauseus or hav a splitting headache

PS. It smth happens on saloon cars which have their roofs retracted,so when they drive at a certain speed in relative to the surrounding air, the air runsoff the wind sheild and creates a low murmur abt 4 hz i think.....

Theorist

correction its infrasound. not contrasound