# How fast do farts travel?

**URL:** <https://boards.straightdope.com/t/how-fast-do-farts-travel/450569>\
**Category:** Factual Questions\
**Created:** [May 25, 2008, 4:20pm UTC](https://boards.straightdope.com/t/how-fast-do-farts-travel/450569 "2008-05-25T16:20:29Z")\
**Posts on this page:** 20\
**Page:** 1

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**Author:** ![Love\_Rhombus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/love_rhombus/32/10694_2.png) [@Love\_Rhombus](https://boards.straightdope.com/u/Love_Rhombus)\
**Post date:** [May 25, 2008, 4:20pm UTC](https://boards.straightdope.com/t/how-fast-do-farts-travel/450569/1 "2008-05-25T16:20:29Z")

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I (sigh) :rolleyes: promised a friend I’d ask. He’s quite proud of his “thunderbutt”. So, what’s the word?

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**Author:** ![Duck\_Duck\_Goose](https://avatars.discourse-cdn.com/v4/letter/d/50afbb/32.png) [@Duck\_Duck\_Goose](https://boards.straightdope.com/u/Duck_Duck_Goose)\
**Post date:** [May 25, 2008, 4:34pm UTC](https://boards.straightdope.com/t/how-fast-do-farts-travel/450569/2 "2008-05-25T16:34:05Z")

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I have absolutely no idea why Google should even return one hit for a search string titled “speed farts”, but it did.

> **[Stupid Facts - Fart Facts](http://mistupid.com/facts/page070.htm)**
>
> Stupid Facts from MIStupid.com

> [@](#):
>
> Farts have been clocked at a speed of 10 feet per second.

Your friend may take that for what it is worth. And you can let Mr. Thunderbutt do the math for how many miles per hour that is.

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**Author:** ![ultrafilter](https://avatars.discourse-cdn.com/v4/letter/u/3d9bf3/32.png) [@ultrafilter](https://boards.straightdope.com/u/ultrafilter)\
**Post date:** [May 25, 2008, 4:39pm UTC](https://boards.straightdope.com/t/how-fast-do-farts-travel/450569/3 "2008-05-25T16:39:25Z")

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Slightly less than 7 mph according to Google calculator.

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**Author:** ![Chez\_Guevara](https://avatars.discourse-cdn.com/v4/letter/c/aeb1de/32.png) [@Chez\_Guevara](https://boards.straightdope.com/u/Chez_Guevara)\
**Post date:** [May 25, 2008, 4:49pm UTC](https://boards.straightdope.com/t/how-fast-do-farts-travel/450569/4 "2008-05-25T16:49:44Z")

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Initial velocity or speed of deceleration?

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**Author:** ![Qadgop\_the\_Mercotan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/qadgop_the_mercotan/32/83_2.png) [@Qadgop\_the\_Mercotan](https://boards.straightdope.com/u/Qadgop_the_Mercotan)\
**Post date:** [May 25, 2008, 4:50pm UTC](https://boards.straightdope.com/t/how-fast-do-farts-travel/450569/5 "2008-05-25T16:50:22Z")

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At the speed of smell, of course.

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**Author:** ![Sage\_Rat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sage_rat/32/399_2.png) [@Sage\_Rat](https://boards.straightdope.com/u/Sage_Rat)\
**Post date:** [May 25, 2008, 5:05pm UTC](https://boards.straightdope.com/t/how-fast-do-farts-travel/450569/6 "2008-05-25T17:05:29Z")

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“Muzzle” velocity or?

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**Author:** ![Chefguy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chefguy/32/138_2.png) [@Chefguy](https://boards.straightdope.com/u/Chefguy)\
**Post date:** [May 25, 2008, 5:11pm UTC](https://boards.straightdope.com/t/how-fast-do-farts-travel/450569/7 "2008-05-25T17:11:19Z")

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Tell him speed is irrelevant. It’s ‘hang time’ that’s critical.

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**Author:** ![Don\_t\_Panic](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/don_t_panic/32/398_2.png) [@Don\_t\_Panic](https://boards.straightdope.com/u/Don_t_Panic)\
**Post date:** [May 25, 2008, 5:12pm UTC](https://boards.straightdope.com/t/how-fast-do-farts-travel/450569/8 "2008-05-25T17:12:45Z")

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Oddly enough, the word “fart” in Danish means “speed”.

Apart from that, I got nuttin’.

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**Author:** ![Myglaren](https://avatars.discourse-cdn.com/v4/letter/m/f1d935/32.png) [@Myglaren](https://boards.straightdope.com/u/Myglaren)\
**Post date:** [May 25, 2008, 5:38pm UTC](https://boards.straightdope.com/t/how-fast-do-farts-travel/450569/9 "2008-05-25T17:38:35Z")

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Oddly enough “Brainiac” tested this recently.  
I don’t watch it and only caught the last half minute but IIRC it was in the region of 4 metres a minute in still air. Stink bombs (half a dozen crushed in a shallow bowl) around 10M/m.

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**Author:** ![Chefguy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chefguy/32/138_2.png) [@Chefguy](https://boards.straightdope.com/u/Chefguy)\
**Post date:** [May 25, 2008, 5:41pm UTC](https://boards.straightdope.com/t/how-fast-do-farts-travel/450569/10 "2008-05-25T17:41:29Z")

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[QUOTE=Peak Banana]  
Oddly enough, the word “fart” in Danish means “speed”.

Apart from that, I got nuttin’.  
[/QUOTE]

And in German, it means ‘exit’. Okay, it’s actually ‘fahrt’. Okay, _ausfahrt_, if you want to get all technical about it.

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**Author:** ![chowder](https://avatars.discourse-cdn.com/v4/letter/c/977dab/32.png) [@chowder](https://boards.straightdope.com/u/chowder)\
**Post date:** [May 25, 2008, 5:43pm UTC](https://boards.straightdope.com/t/how-fast-do-farts-travel/450569/11 "2008-05-25T17:43:02Z")

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Lit or unlit?

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**Author:** ![Love\_Rhombus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/love_rhombus/32/10694_2.png) [@Love\_Rhombus](https://boards.straightdope.com/u/Love_Rhombus)\
**Post date:** [May 25, 2008, 6:00pm UTC](https://boards.straightdope.com/t/how-fast-do-farts-travel/450569/12 "2008-05-25T18:00:20Z")

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[QUOTE=chowder]  
Lit or unlit?  
[/QUOTE]

Now my damnable curiosity is peaked: how fast are lit ones? And how hot?

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**Author:** ![AskNott](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/asknott/32/5790_2.png) [@AskNott](https://boards.straightdope.com/u/AskNott)\
**Post date:** [May 25, 2008, 6:11pm UTC](https://boards.straightdope.com/t/how-fast-do-farts-travel/450569/13 "2008-05-25T18:11:41Z")

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[QUOTE=Peak Banana]  
Oddly enough, the word “fart” in Danish means “speed”.

Apart from that, I got nuttin’.  
[/QUOTE]

So, “fart speed” is redundant, like “pizza pie.”

**Love Rhombus** , unless your rumble-sphinctered pal is asking about muzzle velocity, the sound runs at Mach 1. The aromatic particles travel as fast as the air they’re pooted into. In a wind tunnel, a fart could travel at 200mph. Other than that, it depends on the local wind speed. A naked farter would have a brief, or boxer, advantage over a clothed one, because of the exit delay.

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**Author:** ![elmwood](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/elmwood/32/3060_2.png) [@elmwood](https://boards.straightdope.com/u/elmwood)\
**Post date:** [May 25, 2008, 6:15pm UTC](https://boards.straightdope.com/t/how-fast-do-farts-travel/450569/14 "2008-05-25T18:15:24Z")

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Well, the anal reverberation travels at the speed of sound.

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**Author:** ![Santo\_Rugger](https://avatars.discourse-cdn.com/v4/letter/s/e95f7d/32.png) [@Santo\_Rugger](https://boards.straightdope.com/u/Santo_Rugger)\
**Post date:** [May 25, 2008, 6:17pm UTC](https://boards.straightdope.com/t/how-fast-do-farts-travel/450569/15 "2008-05-25T18:17:51Z")

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If one were to model this phenomenon, a Gaussian plume would probably be the most straightforward method. So, what do we know? According to the site submitted by **Duck Duck Goose:**

> [@](#):
>
> On the average a fart is composed of about 59% nitrogen, 21% hydrogen, 9% carbon dioxide, 7% methane, and 4% oxygen.

We can use that info to find the expected density of the gas using the ideal gas law comparing 98.6F to STP. For the purposes of this equation, we’d assume the stinky parts are homogeneous with the bulk of the fart at least until the room is filled. We’d also assume that the plume would have a turbulent interface.

There would have to be two parts to the equation, one with a pure momentum flux (buoyancy), that would be used in the case of a person sitting down (with their sphincter pointing down, therefore not imparting any horizontal component into the plume’s velocity vector). The additional part, the mass flux, would therefore (and obviously) take into account the horizontal velocity imparted onto the plume by the bum. Finally, ambient wind speed must be taken into account.

Now, to use my least favorite textbook phrase: I’ll leave the solution to the reader.

🆒

Disclaimer: I took most of this info about plumes from the wiki page. Most of what I know about plumes is from reading about how a MEOI (maximally exposed offsite individual) would be effected in the event of a radionuclide spill. Most of the actual simulations are done via computer programs.

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**Author:** ![WarmNPrickly](https://avatars.discourse-cdn.com/v4/letter/w/d78d45/32.png) [@WarmNPrickly](https://boards.straightdope.com/u/WarmNPrickly)\
**Post date:** [May 25, 2008, 6:19pm UTC](https://boards.straightdope.com/t/how-fast-do-farts-travel/450569/16 "2008-05-25T18:19:05Z")

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Farts travel like the wind.

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**Author:** ![Love\_Rhombus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/love_rhombus/32/10694_2.png) [@Love\_Rhombus](https://boards.straightdope.com/u/Love_Rhombus)\
**Post date:** [May 25, 2008, 6:30pm UTC](https://boards.straightdope.com/t/how-fast-do-farts-travel/450569/17 "2008-05-25T18:30:08Z")

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[QUOTE=WarmNPrickly]  
Farts travel like the wind.  
[/QUOTE]

AANNNND that’s just such a perfect name/subject pairing that I salute you.

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**Author:** ![Muffin](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/muffin/32/4341_2.png) [@Muffin](https://boards.straightdope.com/u/Muffin)\
**Post date:** [May 25, 2008, 8:25pm UTC](https://boards.straightdope.com/t/how-fast-do-farts-travel/450569/18 "2008-05-25T20:25:01Z")

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[QUOTE=Peak Banana]  
Oddly enough, the word “fart” in Danish means “speed”.

Apart from that, I got nuttin’.  
[/QUOTE]  
I always did wonder why ski wax was labeled “Fart Wax”. Nice to know that it isn’t due to the nature of tucking.

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**Author:** ![Ignatz](https://avatars.discourse-cdn.com/v4/letter/i/3be4f8/32.png) [@Ignatz](https://boards.straightdope.com/u/Ignatz)\
**Post date:** [May 25, 2008, 8:50pm UTC](https://boards.straightdope.com/t/how-fast-do-farts-travel/450569/19 "2008-05-25T20:50:06Z")

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[QUOTE=Chefguy]  
And in German, it means ‘exit’. Okay, it’s actually ‘fahrt’. Okay, _ausfahrt_, if you want to get all technical about it.  
[/QUOTE]

Oh, really? When I was in the German train stations, I always held my nose near those signs and thought they were for the toilets. But when I went to them, I found myself outside.

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**Author:** ![K364](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/k364/32/5_2.png) [@K364](https://boards.straightdope.com/u/K364)\
**Post date:** [May 25, 2008, 11:15pm UTC](https://boards.straightdope.com/t/how-fast-do-farts-travel/450569/20 "2008-05-25T23:15:16Z")

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How nice to know that you are snorting up gas molecules that were in some other person’s intestines only 1 second ago.

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