# Flatulence - Loud or Silent?

**URL:** <https://boards.straightdope.com/t/flatulence-loud-or-silent/730373>\
**Category:** Factual Questions\
**Created:** [September 8, 2015, 7:55pm UTC](https://boards.straightdope.com/t/flatulence-loud-or-silent/730373 "2015-09-08T19:55:10Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![cuz789n10](https://avatars.discourse-cdn.com/v4/letter/c/4af34b/32.png) [@cuz789n10](https://boards.straightdope.com/u/cuz789n10)\
**Post date:** [September 8, 2015, 7:55pm UTC](https://boards.straightdope.com/t/flatulence-loud-or-silent/730373/1 "2015-09-08T19:55:10Z")

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So why do some farts come out noisy and others silent?

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**Author:** ![Duckster](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/duckster/32/1244_2.png) [@Duckster](https://boards.straightdope.com/u/Duckster)\
**Post date:** [September 8, 2015, 8:40pm UTC](https://boards.straightdope.com/t/flatulence-loud-or-silent/730373/2 "2015-09-08T20:40:44Z")

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loudness = ( distance\_to\_others / smelliness )^2

> [@](#):
>
> Contrary to movies and television aimed at school age boys, a big loud fart is rarely a stinky one. As you might expect there is actually some science behind this. Most farts come from swallowed air which is mostly nitrogen and CO2 and tend to be fairly odorless. The bubbles from theses farts are large in volume and thusly, produce the largest sounds. It is actually the bacterial fermentation and digestions process that produce the various pungent gases in other farts. The bubbles for these farts are usually much smaller and smellier and because of their size do not produce much sound lending them the common title “silent but deadly”.

[http://www.onlineeducation.net/farts](http://www.onlineeducation.net/farts)

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**Author:** ![Tim\_R.Mortiss](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tim_r.mortiss/32/142_2.png) [@Tim\_R.Mortiss](https://boards.straightdope.com/u/Tim_R.Mortiss)\
**Post date:** [September 9, 2015, 6:29pm UTC](https://boards.straightdope.com/t/flatulence-loud-or-silent/730373/3 "2015-09-09T18:29:12Z")

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> [@](#):
>
> …lending them the common title “silent but deadly”.

Sometimes called “Silent but Violent.”

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**Author:** ![Omar\_Little](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/omar_little/32/269_2.png) [@Omar\_Little](https://boards.straightdope.com/u/Omar_Little)\
**Post date:** [September 9, 2015, 7:11pm UTC](https://boards.straightdope.com/t/flatulence-loud-or-silent/730373/4 "2015-09-09T19:11:36Z")

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Does sphincter tightness have anything to do with decibel level of the fart?

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**Author:** ![CookingWithGas](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cookingwithgas/32/485_2.png) [@CookingWithGas](https://boards.straightdope.com/u/CookingWithGas)\
**Post date:** [September 9, 2015, 7:26pm UTC](https://boards.straightdope.com/t/flatulence-loud-or-silent/730373/5 "2015-09-09T19:26:05Z")

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> [@Omar\_Little](#):
>
> Does sphincter tightness have anything to do with decibel level of the fart?

No, that controls the pitch.

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**Author:** ![Kelevra](https://avatars.discourse-cdn.com/v4/letter/k/97f17d/32.png) [@Kelevra](https://boards.straightdope.com/u/Kelevra)\
**Post date:** [September 9, 2015, 8:01pm UTC](https://boards.straightdope.com/t/flatulence-loud-or-silent/730373/6 "2015-09-09T20:01:39Z")

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> [@CookingWithGas](#):
>
> No, that controls the pitch.

Excellent post/user name combo!