2492: Commonly Mispronounced Equations

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Commonly Mispronounced Equations
"Epsihootamoo doopsiquorps" --the Schrödinger equation for the hydrogen atom
Title text: "Epsihootamoo doopsiquorps" --the Schrödinger equation for the hydrogen atom


Ambox notice.png This explanation may be incomplete or incorrect: Created by a LAGRONJ EYSIBARYMOODMOOSIOYLERSIBRYMOOAMOOBAMOOSIMASIBRSIQORTFAHMOOVYFAHMOOVY. Please mention here why this explanation isn't complete: the elided equation in the incomplete notice needs explanation. It would be interesting for more people to weigh in on personal history eliding equations. Do NOT delete this tag too soon.
If you can address this issue, please edit the page! Thanks.

This comic is a collection of very commonly used physics and mathematical equations, along with their "correct" pronunciations. Equations are normally voiced out loud either by their names ("Mass–energy equivalence") or by saying the parts out loud using normal linguistic rules ("E equals M C squared"). This comic instead asserts that equations are meant to be said out loud like words, using their own set of phonic rules.

Though this premise may seem absurd, sometimes this kind of pronunciation is used as an abbreviation or a mnemonic device. For example, the equation A=Pert used for compound interest is commonly taught and pronounced as the "pert" equation, while SOH-CAH-TOA, spoken as one word, is used as a mnemonic for the definitions of the main trigonometric functions: sine = opposite/hypotenuse, cosine = adjacent/hypotenuse, and tangent = opposite / adjacent.

Some nerds have both the trait of using equations as commonly as others might chat, and of finding it entertaining to make up new funny sounds ("input", "pwn"). Saying the equations more rapidly can speed up work or make work seem more enjoyable. This phenomenon is called elision.


Name Representation Pronounciation Explanation
Newton's law of universal gravitation F = G(m₁m₂/r²) Fuh-JAM-er F, gravitational force, is pronounced /f/. G, the gravitational constant, is prononounced as a soft G /dʒ/. The m's (mass 1 and 2) are both pronounced /m/, and the r (radius) is pronounced /r/. The numbers are unpronounced.
Mass–energy equivalence E = mc² EM-cah-too E, energy, is pronounced as a short E /e/, m (mass) is pronounced /m/, c is pronounced as a hard C /k/, and the exponent "2" is pronounced "two".
Pythagorean theorem a² + b² = c² at-BOOT-coot The side length "a" is pronounced as a short a. The side length "b" is pronounced /b/. The hypotenuse "c" is pronounced as a hard "c" /k/. Each exponent 2 is pronounced /t/ for "two", and the vowel sound /u/ of "two" is used as the filler vowel sound.
Area of a circle A = πr² APP-er-too A, the area, is pronounced as a short a. Pi is pronounced /p/. R is pronounced /r/. 2 is pronounced "two". For added bonus, this becomes very similar to the word "aperture", which can be described as just the area of a circle.
Shannon entropy H = -Σpᵢlog(pᵢ) Ha-SPLOG-pee H, entropy, is pronounced /h/. The minus sign is unpronounced. Sigma, the summation sign, is pronounced /s/. The first pᵢ is pronounced /p/ with the subscript i unpronounced. log, the logarithm function, is pronounced "log" (like a piece of lumber). The second pᵢ is pronounced /pi/, where the subscript i makes the long e sound /i/.
Ideal gas law PV = nrt PAV-nurt
Euler's identity e^(iπ) = -1 EYE-pin
Newton's 2nd law of motion F = ma FEE-mah The equal sign is pronounced as a long e. This becomes similar to FEMA, the Federal Emergency Management Agency in the United States.
Wave equation (c would conventionally be c²) ∂²u/∂t² = c(∂²u/∂x²) DOOT cah-DOOX
Derivative f'(x) = lim(h→0) (f(x+h)-f(x))/h FAX-lim-oh FAX-uh-fox
Quadratic formula x = (-b±√(b²-4ac))/2a za-BO-ba fak-TOH-ah
Schrödinger equation for a Coulomb potential Eψ = -(ℏ²/2μ)∇²ψ - (q²/r)ψ Epsihootamoo doopsiquorps The form of the Schrödinger equation intended seems to be "epsi" = − (ℏ2/2μ) "hootamoo" 2ψ "doopsi" - (q2/r)ψ "quorps" – where the 4πε0 required by SI units is not present due to a more suitable unit convention. (μ is mu, ψ is psi, ∇ is the nabla or del symbol and pronounced /d/ here.).


Ambox notice.png This transcript is incomplete. Please help editing it! Thanks.

[Each equation is bordered, with a pronunciation guide beneath.]

Commonly Mispronounced Equations

Row 1

F = G m₁m₂/r²

E = mc²

a² + b² = c²

Row 2

A = πr²

H = -Σpᵢlog pᵢ

PV = nrt

Row 3

e^iπ = -1

F = ma

∂²u/∂t² = c ∂²u/∂x²

Row 4

f'(x) = lim h→0 f(x+h) - f(x) / h

x = -b ± √(b² - 4ac) / 2a

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This comic is obviously a take on the generation Z style of writing words without vowels so that they fit on T-Shirts, text messages or to avoid censorship, like "BRLN", "O RLY", "PIX PLZ". Some of the people from that generation are now established scientist, leading their respective fields forward. Obviously this is how they refer to common equations. 13:10, 22 July 2021 (UTC)

I think the wave equation is wrong based on units, but it's been a while. The wave speed ought to be squared. Of course, c could be a squared speed, but it's usually not. 01:22, 22 July 2021 (UTC)

I agree, normally it's written as C squared... The equations in order are 1: Gravitational Attraction, 2: Einstein's Mass / Energy Conversion, 3: Pythagorean Theorem (triangle side relations), 4: Area of a Circle, 5: Entropy equation, 6: Ideal Gas Law, 7: Euler's Identity, 8: Newtons Second law, 9: Wave equation, 10: The derivative of a function f, and, 11: The Quadratic Equation... I don't understand the linguistic rules being applied to the names, but they seem to be visual as much as anything 02:04, 22 July 2021 (UTC)
You should turn that into a table in the explanation. We can have a column where we try to come up with the pronunciation rule. Barmar (talk) 04:10, 22 July 2021 (UTC)

The equation for the thing I have as what it was made by is 𝓛 = i(ѱ-macron)γᵘ(∂ᵤ)ѱ-e(ѱ-macron)γᵘ(Aᵤ + Bᵤ)ѱ - m(ѱ-macron)ѱ - (FᵤᵥFᵘᵛ)/4 here is the link: These are both the links. For archival, this is the thing: LAGRONJ EYSIBARYMOODMOOSIOYLERSIBRYMOOAMOOBAMOOSIMASIBRSIQORTFAHMOOVYFAHMOOVY. 4D4850 (talk) 02:22, 22 July 2021 (UTC)

My friends and I actually pretty often say "PəV-nert" for the ideal gas law. First syllable is kind of vowel-less, sort of a schwa if anything. But also stressed? Didn't know you could stress a schwa but, guess I did. 02:36, 22 July 2021 (UTC)

My teachers always pronounced it PIV-nert. 18:38, 22 July 2021 (UTC)

I think this is the XKCD that has made me laugh the most, out of all 2492.

I'd say it might be the one that made me laugh the most, out of all 2551. I won't, because it didn't, but I could. --4D4850 (talk) 03:23, 22 July 2021 (UTC)
"Doot-ca-doox" is so funny. I'm imagining Pingu saying that.  !!!!

I tried to transcribe these pronunciations into IPA, because reading them like this is kind of ambiguous. I probably got a bunch of stuff wrong though. fəˈdʒæmɚ | ˈɛmkɑˌtu | ætˈbutkut | ˈæpɚˌtu | həˈsplɒgpi | ˈpævnɚt | ˈaɪpɪn | ˈfimɑ | dut kəˈduks | ˈfækslɪmˌoʊ ˈfæksəˌfɒx | zəˈbɔbə fækˈtoʊɑ | ˌɛpsɪˈhutəˌmu ˈdupsɪˌkwɔrps

Why is it a soft G in the gravity equation? Barmar (talk) 04:10, 22 July 2021 (UTC)

I believe it's a reference to the "gif" pronunciation debate. "Fuh-gam-er" is the obvious pronunciation, Randal is facetiously asserting "Fuh-jam-er" is correct.-- 05:00, 22 July 2021 (UTC)
I think it might be because the English letter "G" is pronounced "Gee" (i.e. "Jee"), which made its way into the pronunciation here.BenjaminTheBenevolent (talk) 10:27, 22 July 2021 (UTC)
How would you pronounce the word 'give'? !!!!
(The English letter pronunciation is "Jee". It's also pronounced as an "F" in "Enough" and "" in "Gnome", etc.) 19:37, 28 July 2021 (UTC)

The most similar time when equations are actually 'pronounced' a bit like this is the "soh cah toa" mnemonic for the trigonometric identities - should this be in the explanation? (the comic made at least me think that might be the original inspiration) 06:42, 22 July 2021 (UTC)

How is "soh cah toa" a mnemonic?? It's just a bunch of random letters. Normally you memorize random letters by coming up with words that fit together, not vice versa. I think this is much harder to remember than the thing it is supposedly a mnemonic for. If anyone actually finds it useful, can you explain how it works for you? I've seen this before so I suppose it's a real thing, but I find it baffling. 04:15, 23 July 2021 (UTC)
You ask how it's a mnemonic, yet you say you've seen it before. Think about that for a sec.

Klo876 (talk) 01:58, 24 July 2021 (UTC)

Not sure it's a mnemonic, no, but I was taught SOHCAHTOA by a very good (but strict) maths teacher as in "... (like?) that volcanic eruption". Given we were 10, 11 years old, I don't think we even knew about Krakatoa at that point (despite having also a very good Geography teacher who readily identified lumps of 'Gneissian schist' that I may have brought back from holiday - he also had a much better sense of humour...) so whether I (or the teacher?) was mistaken in understanding "Sohcahtoa" to be purported to be a (now ironically memorable) volcano rather than it was a "it rhymes with..." mnemonic, I don't now know. But since then I have always used SOHCAHTOA to confirm in my mind which trigonometric identity I should use. And, later, I learnt and never forgot that Krakatoa is/was west of Java! 08:20, 23 July 2021 (UTC)
(PS - If I ever have to use the "Many Very Elderly Men Just..." mnemonic (or whatever it is, I was sure it had had Earthenware Vases, but maybe only in a reversed version!), I tend to have to backform it from my unclear recollection of the mnemonic(s) I've been told plus just knowing that it's "Mercury, Venus, Earth, Mars, **, Jupiter, Saturn, Uranus, Neptune*, Pluto-if-we're-counting-it*" (* - except between 1979 and 1999 when it was "...Pluto-definity-counted-at-this-time, Neptune") (** - and then there's possibly an A, B or C here for Asteroid, Belt or Ceres; nobody I know has ever added Kuiper and/or Oort into the string of words to need remembering, though) using very non-mnemonical direct or indirect knowledge about the solar-system, like Clarke's written version of 2001 aiming at Saturn but Kubrik's film 'only' going as far as Jupiter. So I "(Sometimes?) Might Very Earnestly Make And Join Something Unprecedented Never Known Originally" on the spur of the moment.)
The point of soh-cah-toa is that you learn to say it aloud as one word (which is therefore memorable), and then can expand it out as an acronym for sin(x) = o/h, cos(x) = a/h, tan(x) = o/a, which wouldn't be memorable. Much like BIDMAS/PEDMAS is pronounced as one word to learn an acronym. 18:32, 26 July 2021 (UTC)
The circle area might be meant to read out like "upper two", referencing the square. I can't see the same for any of the others though. / 06:52, 22 July 2021 (UTC)
Mneumonics are supposed to make it easier to remember the equations; this collection would actually make it more challenging to remember these. Mind you, as a math tutor, my first thought was that these were attempts at mnemonics that missed the mark, badly. Nutster (talk) 15:04, 22 July 2021 (UTC)

I see nobody has attempted the Transcript yet. (Also I'm wondering how to 'properly' pronounce P-One V-One Over T-One Equals P-Two V-Two Over T-Two.) 10:41, 22 July 2021 (UTC)

I started a transcript. --4D4850 (talk) 16:54, 22 July 2021 (UTC)

Sorry to come in as an amateur, but I think the equation pronounced Ha-SPLOG-pee is actually the equation for Shannon diversity. 11:58, 22 July 2021 (UTC)

In my opinion, most of the contributions here are from people pretending to know more than they do. Edit away. Be bold. 21:04, 22 July 2021 (UTC)

The Pythagorean Theorem one made me think of the AT-AT debate for Star Wars

The wave equation reminded me of Jimmy Durante's Ink A Dinka Doo: https://www.youtube.com/watch?v=EWqi9eWwXvk I think I'm dating myself (no one else will). Barmar (talk) 16:55, 22 July 2021 (UTC)

I don't think it's clear if the provided pronunciations are the Correct ones or the common mispronunciations

It's worth noting that the majority of these equations are especially likely to be elided, and that the way they're routinely elided is generally incorrect - and more than that, the stressed syllable in particular is likely wrong. Especially notably "Fu-Jam-Er" should be "Fu-Gam-Er" and "Pav-Nert" should be "Piv-Nert". The joke works on the level of equation pronunciation being pretty intrinsically funny if you're not familiar with the specific equation, but also on the level of the specific equations having a standard pronunciation that pointedly isn't the one in the comic.

It would be interesting to try and reverse-engineer the original equations behind, for example, "Fus ro dah", or "Avada Kedavra". Cavaler (talk) 12:53, 23 July 2021 (UTC)

What is the pronounciation notation this comic is using?? I can't even find them in Oxford/Cambridge/Merriam-Webster/Collins dictionary, though I think I occasionally see them somewhere else. --Lamty101 (talk) 08:43, 24 July 2021 (UTC)

It's probably not actually right to consider it a notation, per se. It's a trivial method that anyone can use (no need to use funny stuff like ɛ, ʑ or ɖʐ in IPA notation - or remember what they mean!), but it's also liable to inconsistency as you can be inconsistent in both production (some might consider "DOO" or "DU" an acceptible rendering for the same thing) or understanding (if "BAI" is written used, was that as in "goodbye" (see also "BIE") or "eBay" (also could have been "BAE"), etc?). How would you indicate syllable boundaries, "IN-DUH-KAYT" or "IND-UCK-ATE" or ? A Cockney or a Kiwi or a Cajun might each produce and voice notations completely differently. But it's better than nothing. And with either bolding (as in here), italicising or uppercase-contrasting-with-the-rest-in-lowercase you can indicate the stressed syllable(s). Maybe look at Pronunciation respelling for English (I didn't see a further link to qualify any 'standards' for this non-phonomic system, and doubt that there are any that travel well beyond any actual particular narrow dialectical territory).
I actually think it's part of the joke that it's an imprecise 'pronunciation guide', rather than a technically advanced one like /aɪ pʰiː eɪ/ itself is, further confusing the deliberately confused issue. 19:45, 24 July 2021 (UTC)

We teach the impulse-momentum equation f*(delta)t = m*deltaV as FAT MAV. And you're far more likely to hear a mentor remind a student to use 'FAT MAV' than 'the impulse-momentum equation' this comic seemed an obvious evolution that idea. Sraben (talk) 20:54, 25 July 2021 (UTC)

Something similar does indeed happen in reality, when you have to read things like tan y = sinh x, cot y = csch x. Many people read sinh like sin-ch, while some others read it as shine, etc. Yosei (talk) 23:22, 17 August 2021 (UTC)