The physics behind human whistling-where does the sound come from?

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Discussion Overview

The discussion centers on the physics of human whistling, specifically exploring the mechanisms behind sound production when whistling. It examines theoretical aspects, potential models, and the role of anatomical features in sound generation.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation

Main Points Raised

  • One participant suggests that the mouth acts as a resonance chamber, with pitch being altered by the position of the tongue and palate, despite the mouth being open at both ends.
  • Another participant references a wiki article but finds it vague regarding the actual mechanics of whistling.
  • One participant reports differing opinions from physics professors: one claims vibrations are caused by pressurized air at the lips, another suggests that external vortices cause vibrations, and a third believes the tongue acts like a reed to produce sound.
  • A later reply introduces the concept of acoustic resonance, explaining that whistling occurs at the resonance frequencies of the mouth, which can be altered by tongue position and blowing intensity, with initial pressure oscillations resulting from turbulence in the throat and at the lips.

Areas of Agreement / Disagreement

Participants express differing views on the mechanisms of sound production in whistling, with no consensus reached on which explanation is correct.

Contextual Notes

Participants highlight the complexity of the phenomenon, noting that assumptions about the mechanics of whistling may vary and that definitions of terms like "vibration" and "resonance" may influence interpretations.

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The physics behind human whistling--where does the sound come from?

In most whistles, air is split somehow. When humans whistle (by forming a small hole with their lips), this is definitely not the case. I would assume that the mouth is the resonance chamber because pitch can be altered by moving the tongue, palate, etc. However, our mouths are open at BOTH ends. And we can whistle by both exhaling and inhaling. How is it possible that blowing air OUT of our mouths could create enough vibration that then resonates INSIDE out mouths? What is creating the whistling sound, and where, and how?
 
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I have read it. It is very vague about what is actually happening. I have asked a few physics professors about how whistling works.

One person is absolutely adamant that the vibrations are caused because of the air being pressurized as it goes out the lips, causing the lips to vibrate. Another claims that vibrations are caused outside of the mouth, as the air stream forms vortices that interfere with each other. And another insists that the tongue causes vibrations in the mouth, acting like a reed. Which is it? I'm not crazy about any of these explanations.
 


maybe this one is more clear, although still a bit basic:
http://en.wikipedia.org/wiki/Acoustic_resonance

The basics is just moving air inside a hollow tube that's closed at one end will do to produce a clear sound. You can only make whistling sounds at the resonance frequencies of your mouth, because only at the resonance frequencies the pressure changes due to the moving air will get amplified. You can change the resonance frequencies by changing the position of your tongue. You can move to higher order resonance frequencies by blowing harder.

The initial pressure oscillations are caused because the air becomes turbulent in the back of your throat and at your lips.
 

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