# XKCD cartoon: Equations **URL:** \ **Category:** Cafe Society\ **Created:** [August 17, 2018, 8:45pm UTC](https://boards.straightdope.com/t/xkcd-cartoon-equations/819808 "2018-08-17T20:45:51Z")\ **Posts on this page:** 19\ **Page:** 1
**Author:** ![Lumpy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lumpy/32/446_2.png) [@Lumpy](https://boards.straightdope.com/u/Lumpy)\ **Post date:** [August 17, 2018, 8:45pm UTC](https://boards.straightdope.com/t/xkcd-cartoon-equations/819808/1 "2018-08-17T20:45:51Z")
> **[Equations](https://xkcd.com/2034/)** > > All electromagnetic equations: The same as all fluid dynamics equations, but with the 8 and 23 replaced with the permittivity and permeability of free space, respectively. Unfortunately I’m not educated enough to get any of the jokes except for the chemistry equation. Will someone break it down for me? ---
**Author:** ![ebb](https://avatars.discourse-cdn.com/v4/letter/e/c57346/32.png) [@ebb](https://boards.straightdope.com/u/ebb)\ **Post date:** [August 17, 2018, 9:15pm UTC](https://boards.straightdope.com/t/xkcd-cartoon-equations/819808/2 "2018-08-17T21:15:52Z")
You may find this (and the rest of the site) helpful: > **[2034: Equations - explain xkcd](https://www.explainxkcd.com/wiki/index.php/2034:_Equations)** > > Explain xkcd is a wiki dedicated to explaining the webcomic xkcd. Go figure. ---
**Author:** ![ftg](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ftg/32/2801_2.png) [@ftg](https://boards.straightdope.com/u/ftg)\ **Post date:** [August 17, 2018, 9:55pm UTC](https://boards.straightdope.com/t/xkcd-cartoon-equations/819808/3 "2018-08-17T21:55:38Z")
When I saw this I thought of a recent thread where somebody asked about an equation and the answer was more or less it’s a ??? equation. I can’t remember the category that was given. Maybe heat or fluid. I tried Googling for the thread and can’t find it. Google has been failing me on finding threads here recently. Anyone? Ferris? ---
**Author:** ![DPRK](https://avatars.discourse-cdn.com/v4/letter/d/4491bb/32.png) [@DPRK](https://boards.straightdope.com/u/DPRK)\ **Post date:** [August 17, 2018, 10:51pm UTC](https://boards.straightdope.com/t/xkcd-cartoon-equations/819808/4 "2018-08-17T22:51:17Z")
You mean this? [Physicists: What makes sense on this gigantic blackboard, and how much holds together topically? - Factual Questions - Straight Dope Message Board](https://boards.straightdope.com/sdmb/showthread.php?t=696794) Mostly physics there. ---
**Author:** ![Little\_Nemo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/little_nemo/32/3120_2.png) [@Little\_Nemo](https://boards.straightdope.com/u/Little_Nemo)\ **Post date:** [August 18, 2018, 12:32am UTC](https://boards.straightdope.com/t/xkcd-cartoon-equations/819808/5 "2018-08-18T00:32:58Z")
There have been a number of occasions when I didn’t get the punchline in an xkcd strip. But this time, I figured I wouldn’t even understand the explanation of the punchline. ---
**Author:** ![ftg](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ftg/32/2801_2.png) [@ftg](https://boards.straightdope.com/u/ftg)\ **Post date:** [August 18, 2018, 1:54pm UTC](https://boards.straightdope.com/t/xkcd-cartoon-equations/819808/6 "2018-08-18T13:54:23Z")
> [@DPRK](#): > > You mean this? [Physicists: What makes sense on this gigantic blackboard, and how much holds together topically? - Factual Questions - Straight Dope Message Board](https://boards.straightdope.com/sdmb/showthread.php?t=696794) > > Mostly physics there. Nope. I found that one in my search. The one I remember was a question about one on a t-shirt. And it was a single equation like a heat flow one or some such. ---
**Author:** ![digs](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/digs/32/14889_2.png) [@digs](https://boards.straightdope.com/u/digs)\ **Post date:** [August 18, 2018, 2:55pm UTC](https://boards.straightdope.com/t/xkcd-cartoon-equations/819808/7 "2018-08-18T14:55:40Z")
The chemistry equation is funny, treating HEAT like a actual compound. If I take the time to understand the others (yes, I’m willing to spend a semester studying Gauge Theory and Fluid Dynamics) will they be funny, too? ---
**Author:** ![Peter\_Morris](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/peter_morris/32/359_2.png) [@Peter\_Morris](https://boards.straightdope.com/u/Peter_Morris)\ **Post date:** [August 18, 2018, 3:19pm UTC](https://boards.straightdope.com/t/xkcd-cartoon-equations/819808/8 "2018-08-18T15:19:50Z")
Was it any of these? [30 + 30 = 39. Please Explain](https://boards.straightdope.com/sdmb/showthread.php?t=247849) [What’s Your Perspective on the Image on This Shirt?](https://boards.straightdope.com/sdmb/showthread.php?t=504771) [Maxwell’s Equations on a t-shirt: summing up light](https://boards.straightdope.com/sdmb/showthread.php?t=288907) [Looking for science/mathematics shirts!!](https://boards.straightdope.com/sdmb/showthread.php?t=248479) [Lift formula](https://boards.straightdope.com/sdmb/showthread.php?t=762080) [Identify the equation on this t-shirt?](https://boards.straightdope.com/sdmb/showthread.php?t=371315) ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [August 18, 2018, 4:29pm UTC](https://boards.straightdope.com/t/xkcd-cartoon-equations/819808/9 "2018-08-18T16:29:00Z")
It’s possible to explain the joke without explaining the equations themselves. In broad terms, the equations of certain areas of science tend to have certain mathematical features. One who’s at least passingly familiar with those fields can look at such an equation and say, at a glance, “That looks like a relativity equation”, or “that looks like a stat mech equation”, or the like. One might or might not, depending on familiarity with the field in question, be able to take a closer look and say “Oh, yes, that’s the Schwartz-Bupkus Equation”, or the like, but you’ll usually be able to recognize at least the general field. None of the equations in this comic are correct, and most of them don’t even make any sense. But they all _look_ right for equations of the appropriate field. Which is probably a sign of expertise: Anyone can grab a random textbook off of the shelf and pick out some real equation out of it, but it’s tough to come up with a fake equation that _looks_ real. ---
**Author:** ![Little\_Nemo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/little_nemo/32/3120_2.png) [@Little\_Nemo](https://boards.straightdope.com/u/Little_Nemo)\ **Post date:** [August 18, 2018, 4:59pm UTC](https://boards.straightdope.com/t/xkcd-cartoon-equations/819808/10 "2018-08-18T16:59:40Z")
> [@Chronos](#): > > It’s possible to explain the joke without explaining the equations themselves. In broad terms, the equations of certain areas of science tend to have certain mathematical features. One who’s at least passingly familiar with those fields can look at such an equation and say, at a glance, “That looks like a relativity equation”, or “that looks like a stat mech equation”, or the like. One might or might not, depending on familiarity with the field in question, be able to take a closer look and say “Oh, yes, that’s the Schwartz-Bupkus Equation”, or the like, but you’ll usually be able to recognize at least the general field. > > None of the equations in this comic are correct, and most of them don’t even make any sense. But they all _look_ right for equations of the appropriate field. Which is probably a sign of expertise: Anyone can grab a random textbook off of the shelf and pick out some real equation out of it, but it’s tough to come up with a fake equation that _looks_ real. True. But being fake isn’t a joke. CH[sub]2[/sub] + O[sub]4[/sub]N -\> CHO[sub]2[/sub] + HN + O[sub]2[/sub] looks like a chemical equation even though its complete nonsense. But it doesn’t have a punchline. By adding HEAT the way he did, Munroe made a fake chemical equation that was funny. I’m assuming he did the same with the other equations. That they’re not just convincing fakes but that they also contain some detail that is humorous. So that people who understand the science involved can see the fake equation and say something like _“Did you see that? He used έ as a divisor instead of a multiplier. That’s hilarious.”_ ---
**Author:** ![running\_coach](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/running_coach/32/15836_2.png) [@running\_coach](https://boards.straightdope.com/u/running_coach)\ **Post date:** [August 18, 2018, 5:06pm UTC](https://boards.straightdope.com/t/xkcd-cartoon-equations/819808/11 "2018-08-18T17:06:03Z")
> [@Little\_Nemo](#): > > I’m assuming he did the same with the other equations. That they’re not just convincing fakes but that they also contain some detail that is humorous. So that people who understand the science involved can see the fake equation and say something like _“Did you see that? He used έ as a divisor instead of a multiplier. That’s hilarious.”_ [Dilbert](http://dilbert.com/strip/1993-10-2) ---
**Author:** ![Half\_Man\_Half\_Wit](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/half_man_half_wit/32/21766_2.png) [@Half\_Man\_Half\_Wit](https://boards.straightdope.com/u/Half_Man_Half_Wit)\ **Post date:** [August 18, 2018, 5:53pm UTC](https://boards.straightdope.com/t/xkcd-cartoon-equations/819808/12 "2018-08-18T17:53:24Z")
> [@Chronos](#): > > It’s possible to explain the joke without explaining the equations themselves. In broad terms, the equations of certain areas of science tend to have certain mathematical features. One who’s at least passingly familiar with those fields can look at such an equation and say, at a glance, “That looks like a relativity equation”, or “that looks like a stat mech equation”, or the like. One might or might not, depending on familiarity with the field in question, be able to take a closer look and say “Oh, yes, that’s the Schwartz-Bupkus Equation”, or the like, but you’ll usually be able to recognize at least the general field. > > None of the equations in this comic are correct, and most of them don’t even make any sense. But they all _look_ right for equations of the appropriate field. Which is probably a sign of expertise: Anyone can grab a random textbook off of the shelf and pick out some real equation out of it, but it’s tough to come up with a fake equation that _looks_ real. The supposed ‘quantum gravity’-equation doesn’t fit, though: you’d expect to see things like that as the symmetry group of some gauge theory (such as the Standard Model’s SU(3)xSU(2)xU(1)), so this would perhaps better fit the label ‘all grand unified theory equations’. Of course, as written, it’s just nonsense. ---
**Author:** ![ftg](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ftg/32/2801_2.png) [@ftg](https://boards.straightdope.com/u/ftg)\ **Post date:** [August 18, 2018, 10:05pm UTC](https://boards.straightdope.com/t/xkcd-cartoon-equations/819808/13 "2018-08-18T22:05:15Z")
> [@Peter\_Morris](#): > > Was it any of these? > > … I appreciate the effort, but to be clear this was from a thread just a few months ago. ---
**Author:** ![pulykamell](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pulykamell/32/3166_2.png) [@pulykamell](https://boards.straightdope.com/u/pulykamell)\ **Post date:** [August 19, 2018, 1:37am UTC](https://boards.straightdope.com/t/xkcd-cartoon-equations/819808/14 "2018-08-19T01:37:49Z")
> [@ftg](#): > > I appreciate the effort, but to be clear this was from a thread just a few months ago. It’s [this one.](https://boards.straightdope.com/sdmb/showthread.php?p=21072360&styleid=12) ---
**Author:** ![ftg](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ftg/32/2801_2.png) [@ftg](https://boards.straightdope.com/u/ftg)\ **Post date:** [August 19, 2018, 1:19pm UTC](https://boards.straightdope.com/t/xkcd-cartoon-equations/819808/15 "2018-08-19T13:19:29Z")
> [@pulykamell](#): > > It’s [this one.](https://boards.straightdope.com/sdmb/showthread.php?p=21072360&styleid=12) That’s it!!! Thank you. Yeah, comparing the equation on that t-shirt with the fluid dynamics one in the strip shows they are quite different. So **Randall** missed this one. After all, as **watchwolf49** said: “It looks complicated, must be Navier-Stokes …” (Note: I searched Google/this board for “equation” and “fluid dynamics” for the past year and that thread did not turn up.) ---
**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:** [August 20, 2018, 2:26pm UTC](https://boards.straightdope.com/t/xkcd-cartoon-equations/819808/16 "2018-08-20T14:26:15Z")
> [@Chronos](#): > > None of the equations in this comic are correct, and most of them don’t even make any sense. But they all _look_ right for equations of the appropriate field. Which is probably a sign of expertise: Anyone can grab a random textbook off of the shelf and pick out some real equation out of it, but it’s tough to come up with a fake equation that _looks_ real. I am impressed that Munroe has that expertise in all those fields. Actually I’m impressed that \*\*Chronos \*\*knows that all the equations are wrong. I don’t even know what gauge theory _is_. This comic is like the math version of the joke, “Everything in French sounds like lovemaking, everything in Italian sounds like a fight, and everything in German sounds like a command.” ---
**Author:** ![DavidwithanR](https://avatars.discourse-cdn.com/v4/letter/d/3bc359/32.png) [@DavidwithanR](https://boards.straightdope.com/u/DavidwithanR)\ **Post date:** [August 20, 2018, 2:52pm UTC](https://boards.straightdope.com/t/xkcd-cartoon-equations/819808/17 "2018-08-20T14:52:11Z")
> [@CookingWithGas](#): > > I am impressed that Munroe has that expertise in all those fields. Actually I’m impressed that \*\*Chronos \*\*knows that all the equations are wrong. I don’t even know what gauge theory _is_. My gauge theory is “If the needle never moves, or if the needle swings around wildly, the gauge is probably broken.” 🙂 ---
**Author:** ![Lumpy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lumpy/32/446_2.png) [@Lumpy](https://boards.straightdope.com/u/Lumpy)\ **Post date:** [August 20, 2018, 4:14pm UTC](https://boards.straightdope.com/t/xkcd-cartoon-equations/819808/18 "2018-08-20T16:14:27Z")
> [@DavidwithanR](#): > > My gauge theory is “If the needle never moves, or if the needle swings around wildly, the gauge is probably broken.” 🙂 Mine is: “a tool or part will always be exactly one size too large or too small”. ---
**Author:** ![DavidwithanR](https://avatars.discourse-cdn.com/v4/letter/d/3bc359/32.png) [@DavidwithanR](https://boards.straightdope.com/u/DavidwithanR)\ **Post date:** [August 20, 2018, 5:40pm UTC](https://boards.straightdope.com/t/xkcd-cartoon-equations/819808/19 "2018-08-20T17:40:06Z")
> [@Lumpy](#): > > Mine is: “a tool or part will always be exactly one size too large or too small”. That’s because you’re a reasonably good guesser. When I choose a tool or part, it might be exactly right, or nine sizes too large or small - you never know. 🙂