2734: Electron Color

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Electron Color
There's quark color, but that's not really color--it's just an admission by 20th century physicists that numbers are boring.
Title text: There's quark color, but that's not really color--it's just an admission by 20th century physicists that numbers are boring.


In this comic Miss Lenhart is teaching a school physics class. One of her students asks what the color of electrons is.

This is a relevant question for a kid to ask since on many scientific diagrams of atoms, the subatomic particles have been assigned colors to identify them for the reader. Neutrons are generally red, green, or gray; protons red or green and electrons might be blue or yellow. But there is no accepted rule for coloring such diagrams, so the kid may be confused. Additionally, some scientific diagrams use color coding rather than actually representative colors, and the kid may be wondering what color particles actually are.

In completely off-character style, Miss Lenhart actually gives a correct fact ...so "color" isn't even defined for them. and states that, unlike the diagrams, which are colored for convenience, the particles are not colored. She however gives a bogus, pseudoscientific explanation: They're too small to interact with visible light, ... In fact, every optical effect in our world is due to electrons interacting with light. That leads to color because the electrons are usually bound to various atomic nuclei in molecules etc., which leads to differences in how they take up and give out various energies of photon. But the electron itself does not have a particular hue that can be shone upon and absorbed/reflected, it merely governs the possible quanta of energy changes involved in generating the broad spectrum of light that the substance formed of the atom(s) may be seen by. Also protons are far "bigger" than electrons (and would interact strongly!), but their interaction with light (and generally electromagnetic radiation) is rarely observable, because they are shielded by the tiny electrons in ordinary matter. So, whether intended or not, Miss Lenhart is in her usual role of talking bullshit, also see for instance 1519: Venus.

She then continues by saying that electrons are definitely yellow. The reason for this isn't clear. She may be:

  • meaning that they should be yellow on diagrams, because she feels this is the correct way to depict them in drawings of atoms,
  • referring to the Greek etymology of the word electron (elektron is an old name for amber, a yellow gem),
  • merely teasing her young pupils, or
  • stating how she feels they would be, if they could possess color.

But her off-panel pupils take her word for it. One of the kids says "I knew it", to the "fact" that electrons are yellow, and likewise the other pupils completely ignore what Miss Lenhart just told them. The debate then starts as one pupil claims and protons are red?, and another chimes in, with a No, they're gray! This only makes sense in a debate of how to draw atoms, not regarding their actual color, as Miss Lenhart just explained.

The opinions over the colors are probably based on what kind of diagrams people were initially exposed to, leading to a predisposition to think that those colors are 'correct'.

Although individual electrons do not have a color, it's possible to produce a solution of so-called 'solvated' electrons. In ammonia and amines, in certain concentrations, the solution color is blue, and in higher concentrations metallic gold to bronze.

The title text refers to the color charge property of quarks, a property which is part of quantum chromodynamics. In quantum chromodynamics, a quark's color can take one of three values or charges: red, green, and blue. An antiquark can take one of three anticolors: called antired, antigreen, and antiblue. As mentioned by Randall, these have nothing to do with color as we know it, but is just a way to represent interactions between quarks in a sufficiently analogous fashion that avoids inventing entirely new words to describe a particular threefold quality of the necessary inter-quark groupings. And he jokingly says that the 20th century physicists that came up with the three color system did this as as admission that numbers are boring. They could just have called the color charges "1", "2" and "3", though this may imply an unwarranted hierarchy, progression or other standard mathematical relationship that does not actually apply.


[Miss Lenhart is teaching a class. A boy with spiky hair sits at his desks with his hand raised asking a question. Jill sits in front of him looking back at him while leaning an arm on the back of her chair.]
Miss Lenhart: You have a question?
Boy: Yeah-What color are electrons and protons? Are they yellow? Red? Blue?
[Zoom in on Miss Lenhart's head.]
Miss Lenhart: Subatomic particles don't have a color.
Miss Lenhart: They're too small to interact with visible light, so "color" isn't even defined for them.
[Zoom back out but only showing Miss Lenhart. Three pupils reply from off-panel with speech lines coming from starburst at the right edge of the panel.]
Miss Lenhart: That said, electrons are definitely yellow.
Off-panel voice 1: I knew it!
Off-panel voice 2: And protons are red, right?
Off-panel voice 3: What? No! They're gray!

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Electrons have no color?! BUt lIgHTnIng strIKeS aRe YEllOw, aND LigHTNing IS MaDe uP of eLECTrOns. 22:43, 6 February 2023 (UTC)

Actually most colors are emitted by electrons orbiting atoms after absorbing light. The color electrons emit depend on their kinetic energy and available places they can travel, a tiny bit similar to how things change color as they get hotter, but more extreme and general.
I'm pretty sure lighting strikes are white. -- Hkmaly (talk) 20:58, 7 February 2023 (UTC)

It may refer to the Greek etymology of the word "electron". Originally it meant amber, a yellow gem. 23:20, 6 February 2023 (UTC)

But amber isn't yellow - it's... amber. 10:40, 8 February 2023 (UTC)

I can't do formatting, I'm new. Sorry! -- No Idea If There's A Character Limit LMAO (talk) (please sign your comments with ~~~~)

To me, this is 1000% building on the idea of debating the colors of school subjects. I've added a bit of explanation to the text about it. I used my own color associations & reasons (science = green, history = red) as an example, and I'm sure people will disagree with me. Leave your color/subject associations in a reply to this comment, could be a fun little debate! (also, English = blue) Zman350x (talk) 23:50, 6 February 2023 (UTC)

SocStud is yellow, Math is red, Science is green?, ELA is gray, French is blue, and orange is my least favorite subject out of the rest. I have gotten into many arguments with my friends. 00:10, 7 February 2023 (UTC)
Science = Green (green flask bubbling)
Social Studies = Blue (blue and green globe, green is taking)
Math = Red (math is reliable, red is a strong color so i associate it with reliability)
English = Yellow (all other colors are taken)
Also electrons are blue
Iffy (talk) 23:53, 6 February 2023 (UTC)
Science is Green, Math is Red, S.S. is Orange, and ELA is YellowApollo11 (talk) 16:48, 30 April 2024 (UTC)
Hm! I've never heard of school subjects having any assigned colors; much less any debate about it! If we're identifying them by the folders they're kept in, my favorite subject was Ferrari & my least favorite was Porsche.
ProphetZarquon (talk) 04:41, 7 February 2023 (UTC)
I don't recall colour-coded (UK) schoolbooks, in particular (except the "red pirate, green pirate, blue pirate, etc" stories for young kids, the red pirate like only rubies, the green one emeralds, the blue probably sapphires, and had clothing/etc that matched, naturally), but I had (have still, somewhere!) a collection of Usborne Encyclopaedias at home with a veritable rainbow of colours. Mathematics was yellow, I think, Computers a shade of blue, one of the Red or off-Red (slightly pinker, but still deep red) might have been Physics (had geophysics in it, IIRC), I think History was a light-green. I'm sure I never had the whole set, but I had enough to arrange in as close to Richard Of York order as I felt most content to do, when on the bookshelf.
Insert: moot now, but I dug them up. Pinky-Red: Science; Red: Universe; Orange: Prehistoric Life; Yellow(-verging on amber, but faded): History; Yellow(-unfaded): Mathematics; Light-Green: Geography; Green-Blue: Nature; Dark-Blue: Computers And Electronics. Not all have publication dates in them, but (e.g.) the latter is 1983. So you can imagine how up-to-date the contents are not... ;) 16:15, 9 February 2023 (UTC)
Obviously there were colours involved with the school stuff. I'm sure different levels of SPMG (Scottish Primary Maths Group?) workbooks were colour-coded, perhaps more for the benefit of the teacher, though the later SMP ones were probably more just identified as "13a", "5b", etc, to work through various sub-subjects and the increasingly advanced techniques thereof, perhaps coloured with highlights only to not be boring black-on-white monochrome covers.
And there's so many other colour-classifications that I instituted for myself, over the years, showing just how useful a hue can be to represent and differentiate a class of something, such as various 3M-style "post-it"-like arrow stickers stuck into the pages of a book for quick reference to all instances of one particular thing or another. For which I suppose I'm grateful to not having any notable form of colour-blindness, to limit my options. 08:20, 7 February 2023 (UTC)
Personally, I've always thought that English is red, Math is blue, Sciences are green, History is yellow, and "personal events" are orange.
This is completely BS. This is about the diagrams used for drawing atoms where colors are used for different elementary particles. And Randall clearly explains that they do not have real color. And the jokes that people still have feelings for what colors are chosen based on the conventions used where people first learned about atoms. Have removed the color on subjects completely as it has nothing to do with this comic. --Kynde (talk) 09:43, 7 February 2023 (UTC)
PS you cannot be more than 100% on anything :-D --Kynde (talk) 09:46, 7 February 2023 (UTC)

I believe this comic was made in response to a book talk Randall did in Seattle, where this question was actually asked to him in person! If you want to hear it yourself, someone recorded the talk here: https://www.reddit.com/r/xkcd/comments/xjuc4i/a_recording_and_autotranscript_of_randalls_latest/ 00:45, 7 February 2023 (UTC) A random new user

Was it the dorky randall with red hair or the photogenic one with brown hair and blue eyes or am I going wildly mad? 00:51, 7 February 2023 (UTC)

Am I crazy, I always thought of electrons as blue to contrast with the protons which are red172.70.211.89 04:47, 7 February 2023 (UTC)

You're all crazy! Elections are 2817.9am & protons are 1.5am. "Yellow" is over 557,000,000,000am! Maybe you've all got your displays' color gamut set too low?  ;S
ProphetZarquon (talk) 09:18, 7 February 2023 (UTC)
I have also seen protons as red and neutons as white and electron as blue in the diagrams I remember. Never yellow electrons. --Kynde (talk) 09:43, 7 February 2023 (UTC)
I'm not entirely sure about proton and electrons, but neutrons were black. -- Hkmaly (talk) 20:58, 7 February 2023 (UTC)

"This comic appears to "elevate" that discussion to the college level." - considering that the students are considerably smaller than the teacher (notice the heads), I seriously doubt this is meant to be set in a college classroom - high school at most, IMHO. Also, "One common debate among schoolchildren is over the "color" of various subjects. Because of the brightly colored folders commonly used to separate subjects in the binder of a young student, the students tend to associate those colors with the subject." - well, not in any school I ever attended, nor with any school class I've ever worked with. I'd be inclined to dispute that this is at all common.

I agree that this is probably not supposed to be college-level, but the color-subject coordination is definitely real (albeit not a very common topic of debate). 08:01, 7 February 2023 (UTC)
I find it hard to believe Randall is referencing colors of school subjects without alluding to them in any way; to the contrary, I feel fairly certain he's directly referencing the various colors assigned to electrons, protons, quarks, etc, in diagrammatic illustrations of atomic structure. I think the whole first paragraph is way off base (though interesting tangentially).
ProphetZarquon (talk) 09:18, 7 February 2023 (UTC)
I agree with all above here and have corrected the explanation to school class and pupils and diagram colors removing school subject color completely! --Kynde (talk) 09:43, 7 February 2023 (UTC)
Was it also worth removing the synesthesia bit? Entirely unrelated to school-subject organisation-by-colour that I also think was an incarnadine clupea harengus, but very possibly relevent to "but I happen think it's obvious that <concept> is a <hue> thing!"... For consideration, or as a side-note, whether or not you restore that possible reference. 10:42, 7 February 2023 (UTC)

Electrons are blue, right? In all my textbooks (Germany) electrons are blue. Is this a generally accepted addition? 07:13, 7 February 2023 (UTC)

I stopped the explanation saying that electrons were (by implication, solely) yellow. If green is used for a nucleon (neutron? red being proton?), they might choose blue for an electron, as contrast. Or black dot or white (black-outlined) small circle to contrast with whatever the nucleons are with their much bigger circles clumped in the middle.
But, given other regular colour-conventions, I could imagine yellow as a popular 'electron' colour. Either in its own right (influencing the choices given to the other things depicted) or as the main obviously remaining option (the other things having been decided upon first). Horses for courses. And I can imagine cultural/national differences (e.g. what colours your household wiring was set up as, at least before EU standardisation but then red and black still exists in the mindset, despite blue and brown, or whatever it might have been) if not localised 'linguistic puns' to make some choices more 'obvious' than others. 08:20, 7 February 2023 (UTC)
Indeed, yellow is sometimes indicative of electrical hazard, as opposed to red for flame... So many ways to draw associations!
ProphetZarquon (talk) 09:18, 7 February 2023 (UTC)
Yes blue electrons, red protons and white neutrons are probably common on Europe, it is in Denmark. I'm a physicist and word with radioactive isotopes and teach about them. My drawings are red protons and white neutrons and blue electrons. --Kynde (talk) 09:43, 7 February 2023 (UTC)

I don’t know what Ms. Lenhart is talking about. Electrons are blue, protons are red, and neutrons are definitely grey. Not sure how to sign my comment tho. Oh well (talk) 13:00, 7 February 2023 (please sign your comments with ~~~~)

(You sign your comments with a string of ~~~~ (as suggested by the comment at the top of many a comic-discussion page, when you start to edit it)... or you wait for someone else to do what I just did for you, but that's more effort than the four tildes on your part.)
For what it's worth, I'm mostly with you. Red and grey/dark-grey/black in the centre, as you say. Light blue (or yer actual electric blue?) or (bluish?) white electrons. Depends what colour-pallettes are available to the illustrator/modeller, I imagine, and what else needs a distinct colour alongside the basic trio (e.g. yellow fission/fusion "sparky-flame energy things" or general labelling stuff). 13:15, 7 February 2023 (UTC)
I did some data collection on image searches for atom diagrams, and yes, the defacto color standard is protons red, neutrons grey (less commonly yellow or green), and electrons blue.
I like this because it gives opposing colors to the opposing positive and negative charges, (the same color choices as the traditional magnet north and south ends, likely not coincidentally,) and a neutral color to the uncharged neutron.
Which makes me think that when Lenhart says "electrons are yellow" she does not mean in the diagram sense, but rather in the sense "if you make an electron big enough to see, it is yellow".
SomeDee (talk) 16:58, 7 February 2023 (UTC)
electrons are green. y'all are trippin 17:27, 7 February 2023 (UTC)
definitely green. Have none of you ever used a transmission electron microscope? Or an oscilloscope? Green shine everywhere! 09:01, 8 February 2023 (UTC)

I made a survey for this: https://forms.gle/Pu5mkEtBZPUZ6dbb8 RamenChef (talk) 18:03, 7 February 2023 (UTC)

results https://docs.google.com/forms/d/e/1FAIpQLScYkKUvHse7kI1w8OP77fCOso9jiHr7xbB-NOH7xN7rVSvR6g/viewanalytics JohnHawkinson (talk) 20:47, 26 March 2023 (UTC)

Electrons are yellow, protons are red, and neutrons are gray. End of discussion.

What about roses and violets? 10:49, 8 February 2023 (UTC)

Quark is white, or off-white. 10:47, 8 February 2023 (UTC)

I find this comic puzzling. Virtually all colors we see are due to electrons (transitions between different states in atoms, molecules, and solids), so saying they are "too small to interact with visible light" is quite incorrect. 18:48, 8 February 2023 (UTC)
Yeah. They totally interact with visible light. But only with light of specific frequency matching the energy difference between some electron and free higher orbit it can move to. -- Hkmaly (talk) 19:00, 8 February 2023 (UTC)

light is insensitive to features which are much smaller than the optical wavelength.


What language is this? This is and English site, so please write in English. Google Translate detects it as Hungarian, but leaves almost all of the words untranslated. 04:31, 9 February 2023 (UTC)
It's just a past troll. Who has several times said they've finished trolling, or promised to finish trolling in a given instance if only someone would include some word or other in their next edit. (Spoiler: they never stopped, so we just have to deal with it and carry on.)
The 'language' was worked out (it's a conlang that's a mix of actual non-English root words and 'cod Latin'-type transforms, essentially) but I'm not wasting braincells on its inanity or going to make it a 'mainstream thing'. They do worse things to vandalise the site, but that doesn't mean that the above can be left unchallenged as relatively benign.
My advice is to ignore it (or revert it away, if nobody else does that quickly enough). 09:14, 9 February 2023 (UTC)
What is a conlang and what is cod Latin? 15:12, 9 February 2023 (UTC)
"Conlang" means a Constructed language. And I think they actually meant Dog Latin or (more likely, in context) Pig Latin, though "Cod" does sometimes mean a fake/imitation of something, so Pig Latin might perhaps be described as a cod-Latin. Or confusingly misrefered to as such, by accident... - ooo... I'm routing through the exact same IP, which is rare enough when I edit my own submissions. Above editor is probably with the same ISP as me. ;)

The might not have a color not even a quark color, but they do have a flavour. The are quantum flavoured: Electro 16:06, 9 February 2023 (UTC)

Ohoh, Ms. Lenhart, where were you in undergrad? Whenevery you notice that something has interacted with light, it's electrons. -- 09:01, 10 February 2023 (UTC)

The consensus on Quora points toward the colour of electrons being neutral. [1] --Annatars Gift (talk) 10:46, 10 February 2023 (UTC)

Clearly, the antiquark colors should be cyan (for antired), magenta (for antigreen), and yellow (for antiblue). 03:38, 14 February 2023 (UTC)

This seems like an obvious color-association joke... I feel like the explanation completely misses the mark. 06:16, 17 February 2023 (UTC)

As an electron microscopist, I see electrons all day long: Real electrons are green (on the fluorescent screen). -- 13:08, 2 June 2023 (UTC)