Natural frequency of a wine glass

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Discussion Overview

The discussion centers on the natural frequency of wine glasses, particularly in the context of conducting an experiment to break a wine glass using sound waves. Participants explore the variability of frequencies among different glasses and share insights on the equipment needed for such an experiment.

Discussion Character

  • Exploratory
  • Technical explanation
  • Experimental/applied
  • Debate/contested

Main Points Raised

  • One participant inquires about the typical natural frequency of an empty wine glass for a demonstration experiment.
  • Another suggests that the resonant frequency can be determined by pinging the glass and comparing the sound to known musical notes.
  • A participant emphasizes that there is no "typical" frequency for wine glasses, as each glass has a unique frequency, and recommends using a wet finger to find it.
  • There are suggestions to start with a frequency close to the glass's pitch and fine-tune the signal for maximum amplitude.
  • Concerns are raised about using cheaper wine glasses, which may have a wider frequency range and lower amplitude, making them less likely to break.
  • A participant mentions that lead crystal glasses are considered the best for this purpose, as other types of glass may be too soft.

Areas of Agreement / Disagreement

Participants generally agree that the natural frequency varies among different wine glasses and that lead crystal is preferable for the experiment. However, there is no consensus on the specific frequency or the best approach to achieve the desired outcome.

Contextual Notes

Participants note that the effectiveness of the experiment may depend on the quality of the glass and the equipment used, including the type of loudspeaker and the amplitude of the sound wave. There are also references to varying opinions on the price and characteristics of suitable wine glasses.

sniffer
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Does anybody know the typical natural frequency of an empty wine glass?
I want to conduct a demo experiment of breaking a wine glass with
a sound wave from a distance. Has anyone here done it before?

I need a signal generator (sine wave) and an amplifier. What kind of
loudspeaker do I have to use? What frequency?

Thanks.
 
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Ping the wine glass with your finger. The note you hear will be the resonant frequency. Either measure it with a microphone and a-silly-scope, or just compare it with a known note on a piano or guitar or something.
 
sniffer said:
Does anybody know the typical natural frequency of an empty wine glass?
No such thing as a "typical" wine glass frequency. Each glass will be different.
I want to conduct a demo experiment of breaking a wine glass with
a sound wave from a distance. Has anyone here done it before?
I've played around with making wine glasses sound by running a wet finger around the rim. This is what you need to do to find the natural frequency of the glass in question.
I need a signal generator (sine wave) and an amplifier. What kind of loudspeaker do I have to use? What frequency?
The only way to find the frequency you need is to start off as close to the pitch of the glass as you can and then fine tune your generated signal. Wine glasses are high pitched, so I'd say use the best tweeter you have available. In general design your system for maximum amplitude.
 
Also, you can't do this with cheap wine glasses as these have a wider frequency range at which they will resonate, leading to a smaller amplitude when they do - they are therefore reluctant to break unless a very high amplitude signal is applied to them.

You are looking at £30 - £40 a glass ($50 - $60) from what I have been told by someone who pursued this...

Maybe they told me wrong??
 
Yeah, this site says lead crystal glass is best:

Can a very high-pitched scream really shatter glass?
Address:http://ask.yahoo.com/ask/20011212.html

Other glass is too soft by comparison.
 
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