Sound as longitudinal vibrations of air

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Discussion Overview

The discussion revolves around the nature of sound as longitudinal vibrations in air, exploring how sound is produced and transmitted, particularly in relation to human vocalization. Participants examine concepts such as diffraction, interference, and the mechanics of sound propagation in different environments.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant claims that sound originates from vibrations in the neck, specifically from the vocal cords, and questions how sound can be heard from behind a person.
  • Another participant suggests that diffraction is not the only factor in sound transmission and notes that sound can travel through mediums other than air.
  • It is proposed that sound waves can interfere similarly to light waves, with some participants sharing personal experiences of sound intensity variations in different seating positions in concert halls.
  • There is a discussion about the ability to produce sound while blocking the mouth and nose, with some participants asserting that it is impossible to make sound under those conditions, while others challenge this notion by suggesting alternative methods of sound production.

Areas of Agreement / Disagreement

Participants express differing views on the mechanisms of sound production and transmission, particularly regarding the role of diffraction and the ability to produce sound when the mouth and nose are blocked. The discussion remains unresolved with multiple competing perspectives.

Contextual Notes

Some claims depend on specific assumptions about sound propagation and the conditions under which sound can be produced, which are not fully explored or agreed upon in the discussion.

pivoxa15
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Sound is just Longitudinal vibrations of air that are detected from objects like the ear. Hence it originates from a vibrator.

For humans this vibrator is in the neck in the form of a vocal cord. So sound from humans really comes from the neck and the vibrations of air ascend up the neck and comes out from our mouth and nose.

The question is I am able to hear someone's voice even if I am right behind them. Does this occur because of the diffraction of sound which is a wave as it passes through that person's nose and mouth? What is the difference in intensity of sound between someone standing 1m in front and 1m behind a person producing sound?

Another question is sound waves interfere just like any other wave but when minima occurs, the sound doesn't neccessairly cancel (i.e. you would still hear some sound? Whereas light would, ie. dark fringes.
 
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It's not necessarily a diffraction through their nose and mouth. Keep in mind also that air is not the only carrier of sound waves. If I close my mouth and plug my nose, I can still make audible noises.

Air diffracts sound quite a bit, and the room you're in probably reflects sound fairly well. Both of these are the reason that sound spreads in many directions.
 
Just like light, you can consider every point on a sound wave a source of new waves. The sound diffracts through the air.

Sound waves do interfere exactly like light. I have been in orchestra halls where in some seats you could hear almost nothing. Similarly, those fringes are where the intensity is reduced, not where there is no light.
 
KingNothing said:
If I close my mouth and plug my nose, I can still make audible noises.

When I try to do that, whenever I make a sound, it's because I haven't closed my mouth and or nose properly. When they are completely shut, isn't sound from the vocal cord impossible?
 
pivoxa15 said:
When I try to do that, whenever I make a sound, it's because I haven't closed my mouth and or nose properly. When they are completely shut, isn't sound from the vocal cord impossible?
You can puff your cheeks out while your mouth is shut and your nose is plugged, right? Try humming as you puff them out.
 
Hurkyl said:
You can puff your cheeks out while your mouth is shut and your nose is plugged, right? Try humming as you puff them out.


Again when I make a hum noise, it's because I haven't closed by mouth or nose properly.
 

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