Shattering glass with sound?

(Very "basic-basic" theory)

'The magic of resonance' - With Penguinslab videos!

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Here's one that was inspired by an old comic, Tintin. In one of the episodes the professor demonstrates his devastating invention, a speaker system that destroys any glass in a certain vicinity. It worked due to resonance, but what on earth is resonance anyway?

Image courtesy of labinalorry.scenta.co.uk

Image courtesy of www.montereysymphony.org

Resonance is the state of an object when the frequency of its oscillations matches perfectly its natural frequency of vibration. Natural frequencies of vibrations can be observed in simple examples like:

The 'ping' sound when you tap a wineglass
The 'ooong' sound when you blow across an empty glass/metal tube or bottle (like in a xylophone)
Waves crashing on the seashore
The up and down movement of a bridge
The sounds of a guitar/piano string when plucked
The 'hummm' from a tuning fork

When resonance occurs, the crests of the vibrations match the natural reactions of the object, and thus there is constructive interference: the crests become larger. Each vibration after this adds to the crest until something bad happens... like a bridge toppling over (the Tacoma Narrows bridge [right] is one hell of a good example of this).

Image courtesy of www.civil.ibaraki.ac.jp

This section is divided into subcategories... jump to: First experiment results or Second experiment results

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