# 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:** 2
**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 10, 2001, 6:43pm UTC](https://boards.straightdope.com/t/velocity-of-flatulence/86233/21 "2001-10-10T18:43:16Z")
> [@](#): > > \*Originally posted by NotMrKnowItAll \* > \*\*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 \*\* This doesn’t work, guys. Once my sphincter is open, the gas just mosies out at its own pace. The sphincter appears to be important in building up the pressure for firing off a good flatus, once that impediment is removed the pressure doesn’t build and “farting”, as we know it, ceases. So science has failed me and I’m sitting here with a tube up my ass. I’m feeling pretty bad about myself. ---
**Author:** ![saudade](https://avatars.discourse-cdn.com/v4/letter/s/c0e974/32.png) [@saudade](https://boards.straightdope.com/u/saudade)\ **Post date:** [October 10, 2001, 8:56pm UTC](https://boards.straightdope.com/t/velocity-of-flatulence/86233/22 "2001-10-10T20:56:16Z")
I remember this as if it was yesterday… I was in 9th grade gym class, running laps around the track. Right when I was entering the bend, near the end zone - a certain Coach Weatherwax, standing on the opposite 40 yard line, let rip the loudest fart I have heard in all my 25 years. Now after I heard it, and looked back to see the proud grin on Coach Weatherwax, I started to catch wind of something. I estimated that the fart had a tremendous volume, equal to the gaseous content of a Chico’s Tacos 3.99 special with what had to be a Dr. Pepper - straw ingested of course. He was approximately 60 yards away. If the speed of sound is roughly 335 meters a second…that meant that the fart was let a little over 1/5 of a second before the smell hit. It took approximately 3.5 seconds for me to think " Whoa!.. I hope I’m not downwind from…SHIT!". So I estimate that the fart’s smell traveled the 60 yards in 3.75 seconds. Where I got stuck was where I tried to make a slope of the exponential decay - I figured the initial velocity was probably several times greater - and at 120 yards or so, it would have dissipated into the general scent. Also, since this was in a football field the metal bleachers would have created a fart echo - perhaps a fartdoppler effect - reverberating the fart in undulating waves. Also there may have been secondary interference. Speaking from experience, if someone lets a really loud one, others seize the opportunity and squeeze off some of their gas with relative impunity. With 10 or 12 other guys along the track that morning, there may have been a compound fart effect (observe dissert. of M. Brooks on that subject, from 1973) An finally, pant thickness is a major factor. As a result, any accurate fart speed measurement must involve a naked subject in an insulated seal level tunnel, with precise calibrating equipment. Any volunteers? ---
**Author:** ![saudade](https://avatars.discourse-cdn.com/v4/letter/s/c0e974/32.png) [@saudade](https://boards.straightdope.com/u/saudade)\ **Post date:** [October 10, 2001, 8:57pm UTC](https://boards.straightdope.com/t/velocity-of-flatulence/86233/23 "2001-10-10T20:57:33Z")
I remember this as if it was yesterday… I was in 9th grade gym class, running laps around the track. Right when I was entering the bend, near the end zone - a certain Coach Weatherwax, standing on the opposite 40 yard line, let rip the loudest fart I have heard in all my 25 years. Now after I heard it, and looked back to see the proud grin on Coach Weatherwax, I started to catch wind of something. I estimated that the fart had a tremendous volume, equal to the gaseous content of a Chico’s Tacos 3.99 special with what had to be a Dr. Pepper - straw ingested of course. He was approximately 60 yards away. If the speed of sound is roughly 335 meters a second…that meant that the fart was let a little over 1/5 of a second before the smell hit. It took approximately 3.5 seconds for me to think " Whoa!.. I hope I’m not downwind from…SHIT!". So I estimate that the fart’s smell traveled the 60 yards in 3.75 seconds. Where I got stuck was where I tried to make a slope of the exponential decay - I figured the initial velocity was probably several times greater - and at 120 yards or so, it would have dissipated into the general scent. Also, since this was in a football field the metal bleachers would have created a fart echo - perhaps a fartdoppler effect - reverberating the fart in undulating waves. Also there may have been secondary interference. Speaking from experience, if someone lets a really loud one, others seize the opportunity and squeeze off some of their gas with relative impunity. With 10 or 12 other guys along the track that morning, there may have been a compound fart effect (observe dissert. of M. Brooks on that subject, from 1973) An finally, pant thickness is a major factor. As a result, any accurate fart speed measurement must involve a naked subject in an insulated sea level tunnel, with precise calibrating equipment. Any volunteers? ---
**Author:** ![saudade](https://avatars.discourse-cdn.com/v4/letter/s/c0e974/32.png) [@saudade](https://boards.straightdope.com/u/saudade)\ **Post date:** [October 10, 2001, 9:01pm UTC](https://boards.straightdope.com/t/velocity-of-flatulence/86233/24 "2001-10-10T21:01:37Z")
I thought it was fixed to where you couln’t double post. I feel like a fartknocker now… ---
**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 10, 2001, 10:26pm UTC](https://boards.straightdope.com/t/velocity-of-flatulence/86233/25 "2001-10-10T22:26:03Z")
> [@](#): > > \*Originally posted by saudade \* > \*\*I feel like a fartknocker now… \*\* No, now **saudade** , don’t be so hard on yourself. It’s just that you used to be a smart feller, now, you’re a fart smeller. 😛 ---
**Author:** ![astro](https://avatars.discourse-cdn.com/v4/letter/a/9dc877/32.png) [@astro](https://boards.straightdope.com/u/astro)\ **Post date:** [October 10, 2001, 11:10pm UTC](https://boards.straightdope.com/t/velocity-of-flatulence/86233/26 "2001-10-10T23:10:43Z")
> [@](#): > > \*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. > > You could also use a lighter and a thermometer, and measure the heat created. > > Either way, this experiment stinks. \*\* Doppler weather radar might be the most appropriate as it is particularly tuned for atmospheric “microbursts”. ---
**Author:** ![Doctordec](https://avatars.discourse-cdn.com/v4/letter/d/cdc98d/32.png) [@Doctordec](https://boards.straightdope.com/u/Doctordec)\ **Post date:** [October 10, 2001, 11:13pm UTC](https://boards.straightdope.com/t/velocity-of-flatulence/86233/27 "2001-10-10T23:13:47Z")
The easiest way is to have someone blow smoke up your ass and then let it out in front of a good slow motion camera with a ruler or scale nearby. It should be a simple matter to look at the film (video ?) and get some idea how far the smoke travelled over time. I think the camera would have to be focused pretty tightly. No, I’m not volunteering for any part of the experiment. Another option might be to wait until it’s really cold outside, say 20 below, eat some good chili, drop trou, and then do the same filming. Assuming the “gas” is warm enough it should be visible just like your breath is under the same conditions. All you high-schoolers may feel free to use this as a science project. ---
**Author:** ![barbitu8](https://avatars.discourse-cdn.com/v4/letter/b/839c29/32.png) [@barbitu8](https://boards.straightdope.com/u/barbitu8)\ **Post date:** [October 11, 2001, 1:52am UTC](https://boards.straightdope.com/t/velocity-of-flatulence/86233/28 "2001-10-11T01:52:25Z")
> [@](#): > > \*Originally posted by saudade \* > \*\*I remember this as if it was yesterday… > > I was in 9th grade gym class, running laps around the track. Right when I was entering the bend, near the end zone - a certain Coach Weatherwax, standing on the opposite 40 yard line, let rip the loudest fart I have heard in all my 25 years. \*\* He just wanted you to catch a second wind. ---
**Author:** ![dil](https://avatars.discourse-cdn.com/v4/letter/d/f04885/32.png) [@dil](https://boards.straightdope.com/u/dil)\ **Post date:** [October 11, 2001, 6:05am UTC](https://boards.straightdope.com/t/velocity-of-flatulence/86233/29 "2001-10-11T06:05:28Z")
You could convince someone in Zero-G to fart, (hey NASA is pretty hard-up for material these days) then you can measure the resulting acceleration (equal and opposite) to determine the force of the fart. Then I suppose you could figure out an average velocity based on the volume of gas that was moved. ---
**Author:** ![Kid\_Gilligan](https://avatars.discourse-cdn.com/v4/letter/k/b19c9b/32.png) [@Kid\_Gilligan](https://boards.straightdope.com/u/Kid_Gilligan)\ **Post date:** [October 11, 2001, 11:42am UTC](https://boards.straightdope.com/t/velocity-of-flatulence/86233/30 "2001-10-11T11:42:27Z")
There are so many variables involved here that an accurate measurement is almost impossible to obtain. You could use the method used by homeless advocacy groups, and gay rights organizations. An accurate count of homeless is difficult since they are not stationary. A count of homosexuals is difficult since the number of “closeted” gays would be hard to determine. The obvious solution: Make up a number that suits you, and stick to it. Since measurement is so difficult, who will be able to dispute your statistics? ---
**Author:** ![lieu](https://avatars.discourse-cdn.com/v4/letter/l/c2a13f/32.png) [@lieu](https://boards.straightdope.com/u/lieu)\ **Post date:** [October 11, 2001, 12:16pm UTC](https://boards.straightdope.com/t/velocity-of-flatulence/86233/31 "2001-10-11T12:16:28Z")
Hey, maybe a radar gun would work on Kiki Farnon’s gerbil. Did anybody else catch the transcript or audio clip about the two felchers that got a gerbil stuck up one of 'em’s anus? Felcher #1 lit a match near felcher #2’s netheregions in an attempt to view and extricate the little tunneling Hogan, which in turn ignited a gas pocket and propelled the suddenly smoking brown gerbil into felcher #1’s nose and broke it. Now that’s a two two punch. If anyone has that transcript and could link to it here, maybe a solution to this important question can be found. ---
**Author:** ![CnoteChris](https://avatars.discourse-cdn.com/v4/letter/c/278dde/32.png) [@CnoteChris](https://boards.straightdope.com/u/CnoteChris)\ **Post date:** [October 11, 2001, 12:32pm UTC](https://boards.straightdope.com/t/velocity-of-flatulence/86233/32 "2001-10-11T12:32:26Z")
**Docterdec** - I dunno about blowing smoke up someone’s ass… that sounds kinda uncomfortable. A far easier method, in my opinion, and one in which the subject gets something out of the experiment too, is simply to head on over to Taco Bell and pick up a couple chili cheese burritos. Not only does that increase the number of trials you’ll get out of the subject, but if my experience is any indication, you’ll have plenty of visible objects to track. ---
**Author:** ![WordMan](https://avatars.discourse-cdn.com/v4/letter/w/e8c25b/32.png) [@WordMan](https://boards.straightdope.com/u/WordMan)\ **Post date:** [October 11, 2001, 12:51pm UTC](https://boards.straightdope.com/t/velocity-of-flatulence/86233/33 "2001-10-11T12:51:59Z")
Two ideas: 1. Tape one end of a piece of paper next to the subject’s sphincter in such a way that the free end of the paper covers said orifice. When the subject cuts loose, videotape the event and measure the rate at which the paper vibrates. Shouldn’t one be able to calculate the velocity of the flatus taking into account the rigidity of the paper, air resistance, etc.? 2. A variation on \*\* saudade’s \*\*fond memory - couldn’t subject ingest a food or other substance that would be discretely identifiable, then fart in front of a detection device that is a specific distance away? The moment that the device detects the particle would enable a standard measure of velocity… Man, whoever cracks this problems (sorry) would surely be doing the world a greater service than any discoverer of a Bose-Einstein condensate… ---
**Author:** ![Vector](https://avatars.discourse-cdn.com/v4/letter/v/dc4da7/32.png) [@Vector](https://boards.straightdope.com/u/Vector)\ **Post date:** [October 11, 2001, 12:52pm UTC](https://boards.straightdope.com/t/velocity-of-flatulence/86233/34 "2001-10-11T12:52:28Z")
All this talk about the speed of smell. Doesn’t anyone consider effective fart distance anymore? ---
**Author:** ![Superdude](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/superdude/32/13450_2.png) [@Superdude](https://boards.straightdope.com/u/Superdude)\ **Post date:** [October 11, 2001, 1:23pm UTC](https://boards.straightdope.com/t/velocity-of-flatulence/86233/35 "2001-10-11T13:23:14Z")
> [@](#): > > \*Originally posted by Anal Scurvy \* > \*\* > So science has failed me and I’m sitting here with a tube up my ass. I’m feeling pretty bad about myself. \*\* Wow. _Deja Vu_\*. The same thing happened to me on prom night. ---
**Author:** ![WordMan](https://avatars.discourse-cdn.com/v4/letter/w/e8c25b/32.png) [@WordMan](https://boards.straightdope.com/u/WordMan)\ **Post date:** [October 11, 2001, 2:19pm UTC](https://boards.straightdope.com/t/velocity-of-flatulence/86233/36 "2001-10-11T14:19:14Z")
> [@](#): > > \*Originally posted by Superdude \* > \*\* > > > [@](#): > > > > \*Originally posted by Anal Scurvy \* > > \*\* > > So science has failed me and I’m sitting here with a tube up my ass. I’m feeling pretty bad about myself. \*\* > > Wow. _Deja Vu_\*. The same thing happened to me on prom night. \*\* Richard? Richard Gere? Wow, I thought “American Gigolo” was your best work… ---
**Author:** ![Superdude](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/superdude/32/13450_2.png) [@Superdude](https://boards.straightdope.com/u/Superdude)\ **Post date:** [October 11, 2001, 3:42pm UTC](https://boards.straightdope.com/t/velocity-of-flatulence/86233/37 "2001-10-11T15:42:15Z")
Nope. Sorry. There wasn’t a gerbil involved in mine. 🙂 ---
**Author:** ![yakboy](https://avatars.discourse-cdn.com/v4/letter/y/a3d4f5/32.png) [@yakboy](https://boards.straightdope.com/u/yakboy)\ **Post date:** [October 11, 2001, 3:46pm UTC](https://boards.straightdope.com/t/velocity-of-flatulence/86233/38 "2001-10-11T15:46:13Z")
> [@](#): > > \*Originally posted by lieu \* > \*\*Did anybody else catch the transcript or audio clip about the two felchers that got a gerbil stuck up one of 'em’s anus? Felcher #1 lit a match near felcher #2’s netheregions in an attempt to view and extricate the little tunneling Hogan, which in turn ignited a gas pocket and propelled the suddenly smoking brown gerbil into felcher #1’s nose and broke it. Now that’s a two two punch. > \*\* I have some concerns about the gerbil-cannon theory. In order for the fart to ignite it must be mixed with oxygen, and as we learned at [http://www.heptune.com/farts.html](http://www.heptune.com/farts.html) it is not typical for farts to contain significant amounts of oxygen prior to emission. Even if enough oxygen drifted in with the gerbil to create a combustible mixture, it seems to me that the gerbil would need to be chambered up in the tube and the point of ignition would have to be behind the critter (upstream, so to speak) to get any kind of “muzzle velocity” built up. ---
**Author:** ![Niobium\_Knight](https://avatars.discourse-cdn.com/v4/letter/n/bc8723/32.png) [@Niobium\_Knight](https://boards.straightdope.com/u/Niobium_Knight)\ **Post date:** [October 11, 2001, 3:51pm UTC](https://boards.straightdope.com/t/velocity-of-flatulence/86233/39 "2001-10-11T15:51:01Z")
surely the original poster’s method using a microphone would just measure the frequency of the sphincter? ---
**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 11, 2001, 5:00pm UTC](https://boards.straightdope.com/t/velocity-of-flatulence/86233/40 "2001-10-11T17:00:56Z")
> [@](#): > > \*Originally posted by WordMan \* > \*\* > Man, whoever cracks this problems (sorry) would surely be doing the world a greater service than any discoverer of a Bose-Einstein condensate… \*\* Didn’t they already discover a Bose-Einstein condensate? [![](http://www.angryflower.com/2001sc.gif) ](http://www.angryflower.com/2001sc.gif) [Previous page](https://boards.straightdope.com/t/velocity-of-flatulence/86233.md?page=1) [Next page](https://boards.straightdope.com/t/velocity-of-flatulence/86233.md?page=3)