# velocity of flatulence **URL:** \ **Category:** Factual Questions\ **Created:** [October 9, 2001, 1:53am UTC](https://boards.straightdope.com/t/velocity-of-flatulence/86233 "2001-10-09T01:53:10Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![ScottHaneda](https://avatars.discourse-cdn.com/v4/letter/s/9d8465/32.png) [@ScottHaneda](https://boards.straightdope.com/u/ScottHaneda)\ **Post date:** [October 9, 2001, 1:53am UTC](https://boards.straightdope.com/t/velocity-of-flatulence/86233/1 "2001-10-09T01:53:10Z")
I was wondering how one might go about accurately measuring the velocity of a fart. I think that by using a microphone to record the sound pressure level you might get a rough idea, since the diaphram inside the mic is being vibrated by the velocity of the sound of the fart. I suppose that by inserting a tube up an ass and connecting that tube to some type of psi guage, a more accurate reading might occur. i wonder what the highest velocity of a fart has ever been recorded? ---
**Author:** ![imthjckaz](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/imthjckaz/32/3223_2.png) [@imthjckaz](https://boards.straightdope.com/u/imthjckaz)\ **Post date:** [October 9, 2001, 2:03am UTC](https://boards.straightdope.com/t/velocity-of-flatulence/86233/2 "2001-10-09T02:03:12Z")
Maybe, you could use a radar gun. You know, position a cop near your ass, and let fly. He is bound to come up with some sort of reading, they always do. You could also use a lighter and a thermometer, and measure the heat created. Either way, this experiment stinks. ---
**Author:** ![johnson](https://avatars.discourse-cdn.com/v4/letter/j/d07c76/32.png) [@johnson](https://boards.straightdope.com/u/johnson)\ **Post date:** [October 9, 2001, 2:05am UTC](https://boards.straightdope.com/t/velocity-of-flatulence/86233/3 "2001-10-09T02:05:42Z")
Isn’t that what an **anumometer** is for? ---
**Author:** ![Violet](https://avatars.discourse-cdn.com/v4/letter/v/ebca7d/32.png) [@Violet](https://boards.straightdope.com/u/Violet)\ **Post date:** [October 9, 2001, 5:49am UTC](https://boards.straightdope.com/t/velocity-of-flatulence/86233/4 "2001-10-09T05:49:49Z")
Here is a starting reference point for such questions: [http://www.heptune.com/farts.html](http://www.heptune.com/farts.html) ---
**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:** [October 9, 2001, 7:23am UTC](https://boards.straightdope.com/t/velocity-of-flatulence/86233/5 "2001-10-09T07:23:10Z")
> [@](#): > > \*\*Originally posted by imthjckaz \*\* > \*Maybe, you could use a radar gun. > > You know, position a cop near your ass, and let fly. He is bound to come up with some sort of reading, they always do. > \* I don’t think this proposed solution addresses the complexities of the problem. Whereas the proximity of a cop (with radar gun) to the ass in question might be enough to measure _farts perpetrated from a motionless position_, it should be accepted that many people (not me of course) move and fart _at the same time_. The only way to measure farts emanating from the ass of a person _already in motion_ is to adapt speed cameras to measure Fart Velocity taking into account the Relative Velocity vis-a-vis the forward (or backward) motion of the Person Doing The Farting. So in future, if you are walking down the road and you pass a speed camera whilst farting, don’t be surprised if it takes your photograph and you subsequently receive a Farting Ticket in the post. ---
**Author:** ![KeithT](https://avatars.discourse-cdn.com/v4/letter/k/e47774/32.png) [@KeithT](https://boards.straightdope.com/u/KeithT)\ **Post date:** [October 9, 2001, 7:30am UTC](https://boards.straightdope.com/t/velocity-of-flatulence/86233/6 "2001-10-09T07:30:11Z")
[http://www.dwyer-inst.com/htdocs/flow/pf.html](http://www.dwyer-inst.com/htdocs/flow/pf.html) Accurate to within 1%. Possibly a bit uncomfortable, but you had to know. 🙂 ---
**Author:** ![Violet](https://avatars.discourse-cdn.com/v4/letter/v/ebca7d/32.png) [@Violet](https://boards.straightdope.com/u/Violet)\ **Post date:** [October 9, 2001, 9:07am UTC](https://boards.straightdope.com/t/velocity-of-flatulence/86233/7 "2001-10-09T09:07:13Z")
“We have lift off!” Good nite! 🙂 ---
**Author:** ![Cougarfang](https://avatars.discourse-cdn.com/v4/letter/c/c67d28/32.png) [@Cougarfang](https://boards.straightdope.com/u/Cougarfang)\ **Post date:** [October 9, 2001, 10:22am UTC](https://boards.straightdope.com/t/velocity-of-flatulence/86233/8 "2001-10-09T10:22:27Z")
> [@](#): > > \*Originally posted by imthjckaz \* > \*\*Either way, this experiment stinks. \*\* _pelts **imthjckaz** with moldy cat food_ bad joke! bad! bad! SIT! 😃 _d&r_ ---
**Author:** ![lieu](https://avatars.discourse-cdn.com/v4/letter/l/c2a13f/32.png) [@lieu](https://boards.straightdope.com/u/lieu)\ **Post date:** [October 9, 2001, 12:08pm UTC](https://boards.straightdope.com/t/velocity-of-flatulence/86233/9 "2001-10-09T12:08:04Z")
Radar gun? Are you willing to make allowances and corrections for the doppler effect? That seems like a pain in the ass. Why not just use an infrared camera on a farting eskimo? Resolution will be much improved and it won’t stink until spring. ---
**Author:** ![El\_Zagna](https://avatars.discourse-cdn.com/v4/letter/e/d2c977/32.png) [@El\_Zagna](https://boards.straightdope.com/u/El_Zagna)\ **Post date:** [October 9, 2001, 1:45pm UTC](https://boards.straightdope.com/t/velocity-of-flatulence/86233/10 "2001-10-09T13:45:46Z")
I’ve given this a lot of thought and I can see several possible approaches. First… **Doppler Radar** - Just go down to the local news station and ask the weatherguy if you can check out his equipment. Be sure to explain to him what you are trying to do and remind him that it is in the name of science, otherwise he may call the police. **Wind gauges** - You’ll need to go to an airport for this. Just back up to one of those cupped twirly wind things, get down in a football stance and let her rip. Keep at it until you get a good reading. Don’t worry about the extra security these days - I’m sure they won’t mind. **High speed cameras** - This has been discussed already. The trick is observing an invisible gas. Perhaps infra-red film or night vision goggles. **Substituting liquid expellorant** - This assumes that the velocity of a liquid is roughly the same as that of a gas. If that’s the case you could measure the **distance** the liquid is propelled, apply some fancy calculations, and figure the velocity. I’m sure some aerospace engineers could help you with this - this is, after all, rocket science. Any other questiuons for us, Scott? ---
**Author:** ![NotMrKnowItAll](https://avatars.discourse-cdn.com/v4/letter/n/6bbea6/32.png) [@NotMrKnowItAll](https://boards.straightdope.com/u/NotMrKnowItAll)\ **Post date:** [October 9, 2001, 5:26pm UTC](https://boards.straightdope.com/t/velocity-of-flatulence/86233/11 "2001-10-09T17:26:17Z")
I have a sure-fire way to measure the average velocity. It’s rather simple affair, all you need is gassy food, a bath, a length of tubing of known inside diameter(1 cm ID would be grand), stopwatch, and a graduated cylinder. Here’s the protocol: 1. Draw up the bath, disrobe and insert one end of the tubing a short way up your anus. 2. Submerge the graduated cylinder, being careful to remove all air bubbles. 3. Get in the tub, invert the cylinder and insert free end of tube in cylinder. The air in the tubing will be replaced 1 to 1 with flatus (right word?). 4. Time several farts, and note volume of water displaced. The average velocity, in M/s is given by the equation: v=T/(1000_pi_r[sup]2[/sup]\*t) Where, T is Total fart volume in liters (the 1000 converts liters to M[sup]3[/sup]) r is tube inside radius in Meters t is time in seconds ---
**Author:** ![NotMrKnowItAll](https://avatars.discourse-cdn.com/v4/letter/n/6bbea6/32.png) [@NotMrKnowItAll](https://boards.straightdope.com/u/NotMrKnowItAll)\ **Post date:** [October 9, 2001, 5:31pm UTC](https://boards.straightdope.com/t/velocity-of-flatulence/86233/12 "2001-10-09T17:31:44Z")
Oh, forget that. The velocity is inversely proportional to the orifice cross sectional area. ---
**Author:** ![lieu](https://avatars.discourse-cdn.com/v4/letter/l/c2a13f/32.png) [@lieu](https://boards.straightdope.com/u/lieu)\ **Post date:** [October 9, 2001, 7:22pm UTC](https://boards.straightdope.com/t/velocity-of-flatulence/86233/13 "2001-10-09T19:22:34Z")
Are you suggesting that sphincters are migratory? ---
**Author:** ![Anal\_Scurvy](https://avatars.discourse-cdn.com/v4/letter/a/c57346/32.png) [@Anal\_Scurvy](https://boards.straightdope.com/u/Anal_Scurvy)\ **Post date:** [October 9, 2001, 7:35pm UTC](https://boards.straightdope.com/t/velocity-of-flatulence/86233/14 "2001-10-09T19:35:58Z")
I love you guys ---
**Author:** ![imthjckaz](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/imthjckaz/32/3223_2.png) [@imthjckaz](https://boards.straightdope.com/u/imthjckaz)\ **Post date:** [October 9, 2001, 10:28pm UTC](https://boards.straightdope.com/t/velocity-of-flatulence/86233/15 "2001-10-09T22:28:53Z")
> [@](#): > > \*Originally posted by Nostradamus \* > \*\* > > > [@](#): > > > > \*\*Originally posted by imthjckaz \*\* > > \*Maybe, you could use a radar gun. > > > > You know, position a cop near your ass, and let fly. He is bound to come up with some sort of reading, they always do. > > \* > > I don’t think this proposed solution addresses the complexities of the problem. > > Whereas the proximity of a cop (with radar gun) to the ass in question might be enough to measure _farts perpetrated from a motionless position_, it should be accepted that many people (not me of course) move and fart _at the same time_. > > The only way to measure farts emanating from the ass of a person _already in motion_ is to adapt speed cameras to measure Fart Velocity taking into account the Relative Velocity vis-a-vis the forward (or backward) motion of the Person Doing The Farting. > \*\* Your right, what was I thinking! I posted a half-ass answer to a big-ass question. Research, yes, I must do more research. As soon as I finish this burrito, I’ll let you guys know how things come out. Science is fun. 😛 ---
**Author:** ![Coldfire](https://avatars.discourse-cdn.com/v4/letter/c/a587f6/32.png) [@Coldfire](https://boards.straightdope.com/u/Coldfire)\ **Post date:** [October 9, 2001, 11:06pm UTC](https://boards.straightdope.com/t/velocity-of-flatulence/86233/16 "2001-10-09T23:06:55Z")
> [@](#): > > \*Originally posted by lieu \* > \*\*Why not just use an infrared camera on a farting eskimo? Resolution will be much improved and it won’t stink until spring. \*\* You know, I hate to be PC, but I feel it’s my duty to point it out to you that the accepted term these days is “a _flatulating_ eskimo”. Carry on. You guys make me snicker. 😃 ---
**Author:** ![johnson](https://avatars.discourse-cdn.com/v4/letter/j/d07c76/32.png) [@johnson](https://boards.straightdope.com/u/johnson)\ **Post date:** [October 9, 2001, 11:08pm UTC](https://boards.straightdope.com/t/velocity-of-flatulence/86233/17 "2001-10-09T23:08:09Z")
**Anumometer** …anemometer…anus…get it? And “this experiment stinks” is high humor? Nevermind… 🙂 ---
**Author:** ![Strainger](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/strainger/32/244_2.png) [@Strainger](https://boards.straightdope.com/u/Strainger)\ **Post date:** [October 10, 2001, 5:59pm UTC](https://boards.straightdope.com/t/velocity-of-flatulence/86233/18 "2001-10-10T17:59:36Z")
Use a [Pitot tube](http://www.wsu.edu/~gmhyde/433_web_pages/433fluidflow/pitot_tube.html). Duuuuuhh. ---
**Author:** ![Nymaz](https://avatars.discourse-cdn.com/v4/letter/n/d9b06d/32.png) [@Nymaz](https://boards.straightdope.com/u/Nymaz)\ **Post date:** [October 10, 2001, 6:27pm UTC](https://boards.straightdope.com/t/velocity-of-flatulence/86233/19 "2001-10-10T18:27:08Z")
> [@](#): > > _lieu gave us this poser:_ > Are you suggesting that sphincters are migratory? I suppose it could grip the coconut with its cheeks… ---
**Author:** ![jab1](https://avatars.discourse-cdn.com/v4/letter/j/ee7513/32.png) [@jab1](https://boards.straightdope.com/u/jab1)\ **Post date:** [October 10, 2001, 6:32pm UTC](https://boards.straightdope.com/t/velocity-of-flatulence/86233/20 "2001-10-10T18:32:26Z")
Well, this should shoot down the notion that people who surf the internet have too much time on their hands. I mean, this is \*important! [Next page](https://boards.straightdope.com/t/velocity-of-flatulence/86233.md?page=2)