explain xkcd - User contributions [en]

Talk:2775: Siphon

2023-05-12T18:44:23Z

172.71.254.100:

My understanding was that siphoning can essentially be explained by the Bernoulli equation? There is a difference in potential energy between the upper and lower container so it flows. The weight of water in the downhill part of the tube pulls water up the uphill section of the tube (think like a vacuum), and so on until there's either no difference in head or no more water. Siphoning will work with any diameter tube. [[Special:Contributions/172.70.91.151|172.70.91.151]] 15:43, 12 May 2023 (UTC)
:That's right. The only mention of capillary action in the siphon wikipedia article is when talking about phenomenon that *isn't* a siphon. [[User:Barmar|Barmar]] ([[User talk:Barmar|talk]]) 16:15, 12 May 2023 (UTC)

Agree, capillary action does not seem to be referenced or implied in the comic, presenting only the (not "functioning") siphon phenomenon. [[Special:Contributions/172.68.134.142|172.68.134.142]] 16:23, 12 May 2023 (UTC)
:Seconded/thirded. Capillary action isn't even what they were expecting. The small amount of water in the lowe receptical indicates they correctly ''filled'' the tube, but then as the longer length drained it did not then induce further flow up and over through the shorter length. e.g. nature no longer abhored the resulting vacuum (or there was increased negative-pressure vapourisation, beyond that previously expected, or other method of seepage 'airlock'-breaking) and thus the short-end also drained straight back out again instead of becoming a potentially self-sustaining inflow to the whole siphoning setup.
:While the capilliary action element ''could'' induce the start of a rather limited 'empty' siphon setup to start (maybe, I'd have doubts about the 'fluid friction' actually acting against the gravity-feed part, once the surface-tension bit has "climbed the mountain" and started to merely seep out of the other end, almost incidentally, for a sufficiently thin tubing where CA is a significant factor), this suddenly failing for whatever reason (surface-tension effects being nullified) wouldn't then send a token amount of water into the low bucket, nor particularly stop unrelated siphon-flow from continuing properly (in fact, suddenly 'interaction-free' liquid and tubing might siphon ''faster'', with effectively zero fluid boundary effects dragging on the induced flow).
:But perhaps someone with more QFD experience could explain where my assessment is wrong. So not going to personally rewrite the current Explanation intro just now. [[Special:Contributions/172.70.162.161|172.70.162.161]] 16:21, 12 May 2023 (UTC)
:I'd like to contribute as one more data point. I also don't see capillary action as being relevant. In particular, as another commenter said, the water in the lower bucket quite clearly supports the idea that the siphon effect was the subject of the characters' confusion. How else is Randall supposed to depict the siphon effect anyway? I agree that the drawing alone ''could'' also suggest capillary action is what's being investigated, but I don't think it suggests that the caption has ''incorrectly'' referred to it as the siphon effect. [[Special:Contributions/172.71.254.100|172.71.254.100]] 18:44, 12 May 2023 (UTC)

2770: Tapetum Lucidum

2023-05-02T21:38:11Z

172.71.254.100: /* Explanation */

{{comic
| number = 2770
| date = May 1, 2023
| title = Tapetum Lucidum
| image = tapetum_lucidum_2x.png
| imagesize = 412x492px
| noexpand = true
| titletext = Using a reflective wall in a game to give one shot two chances to hit is called a double-tapetum lucidum.
}}

==Explanation==
{{incomplete|Created by BILL NYE'S CAT - Please change this comment when editing this page. Do NOT delete this tag too soon.}}

{{w|Bill Nye}}, best known for his children's educational series ''Bill Nye the Science Guy'', wearing the same lab coat as in [[200: Bill Nye]], beats an unseen player (presumably [[Randall]]) in an online multiplayer game resembling {{w|XPilot}}, in which players pilot spaceships using simulated rocket physics and attempt to shoot and kill each other. During a laser battle, Bill Nye provides a scientific explanation for the {{w|tapetum lucidum}}, the layer behind the {{w|retina}} of a cat's eye. He explains that the layer reflects back some of the light that bounces off the retina, giving it a second chance to hit the retina again. This allows a cat's eye to capture more light than it otherwise would, and thus improves their night vision. It's also why [https://carnegiemnh.org/meowfest-why-do-cat-eyes-glow-in-the-dark/ cat's eyes appear to glow in the dark].

At the same time, Bill Nye's battle tactic in the online game perfectly analogizes the point he is making. His spaceship is firing energy pulses into the path of an approaching ship in an attempt to destroy it. Due to the difficulty of hitting a small, fast-moving target, it's likely that most or all of these shots will miss. However, because Bill Nye is firing at a reflective wall, each shot that misses bounces back into the path of the opponent's ship, giving it a second chance to hit the target and effectively doubling the density of the firepower. With double the number of shots to avoid, the opponent's ship is hit and explodes.

In the analogy, the weapon shots fired by Bill Nye's ship are the light photons entering the cat's eye, the reflective wall is the tapetum lucidum, and the opponent's ship is a retinal cell. Destroying the opponent's ship with a shot is analogous to a light photon being absorbed by the cat's retina (and therefore seen). If the reflective wall hadn't been there, the ship might have survived, which means the retina would never have seen that photon.

Randall presumably considers this "extra infuriating" because Bill Nye is showing off his scientific knowledge in some other field while also beating him in the game.

The title text refers to "tapetum lucidum" and uses "double tap" in the way that online games, memes, and films refer to shooting something twice in rapid succession to ensure its demise. This phrase is famously{{Actual citation needed}} used in the film "Zombieland," and is the subtitle of the 2019 "Zombieland: Double Tap" sequel.

==Transcript==
:[Two triangles with two long sides of equal length (isosceles triangles) but with the short side curving a bit in, are moving inside a black structure, their movement indicated with three and two curved lines below the left and above the right triangle. Both triangles shoots green lasers out of their sharp tip, indicating they represents space ships. They are flying inside a black structure, maybe a maze. There is nothing above the left ship. but below the ships are a black segment making a triangle in the lower left corner. The right ship is inside an opening created by this triangle below it, and another black triangle above it, that centers on the middle of the right side of the panel. The left ship has shot three green laser beams, one of them hits inside the opening on the right triangle and the beam bounces off this wall. But it is not close to the right ship. The right ship has only fires one green laser, which bounces off the left wall also far from the left ship. A voice emanates from the left ship, via a star burst at the top corner. And there are sounds because of the shots it has fired.]
:Left ship: Cats have a shiny layer behind their retina called the tapetum lucidum.
:Laser shots: Pew pew pew

:[Same setting but the scene has panned a bit to the left and up so less of the black walls can be seen. The left ship has moved closer to the right wall and has turned so it's sharp tip points almost straight down, still with three curved lines to indicate movement, probably turning movement. It again fires green lasers at the other ship, four this time, with sounds coming from the shooting. The right spaceship is accelerating forward as indicated with three wavy lines behind it's short side moving in to the line of fire. It seems as though all four lasers might miss it, but one of those that already has passed it, is being reflected up against it from below the left black wall. Again a voice emanates from the left ship via a starburst in the left corner:]
:Left ship: After light passes through the retina, this layer reflects it back through a second time.
:Laser shots: Pew pew

:[Same setting but the scene has again panned a bit to show a different segments of the black walls. The ship originally to the left is now above and a bit to the right of where the right ship originally was, and it is even closer to the right wall. It is not firing any more shots, because the reflected shot from the previous panel has hit the right ship which explodes in large green cloud with the black pieces of the ship inside it, and a huge sound. The tail of the laser shot that hits it can be seen entering the explosion. Three other laser shots from before are still moving down, but might all have missed the ship. There are no movement lines now but again the voice emanates from the left ship via a starburst in the left corner:]
:Left ship: This extra bounce gives photons another chance to interact with the retinal cells...
:Explosion: Boom!

:[A man with short black hair wearing a labcoat is sitting in an office chair typing on his computer while speaking. Below him is a frame with a caption, from which it becomes clear that the man, and the owner of the voice from the left ship, is Bill Nye.]
:Bill Nye: ...Improving their night vision! Isn't science cool?
:Caption: There's something extra infuriating about losing online games to Bill Nye.

{{comic discussion}}

[[Category:Comics with color]]
[[Category:Comics featuring child rapists]]
[[Category:Comics featuring real people]]
[[Category:Video games]]
[[Category:Biology]]
[[Category:Cats]]

2758: My Favorite Things

2023-04-03T23:16:18Z

172.71.254.100: /* Transcript */ Fixed capitalization and wording

{{comic
| number = 2758
| date = April 3, 2023
| title = My Favorite Things
| image = my_favorite_things_2x.png
| imagesize = 277x426px
| noexpand = true
| titletext = When an Ur guy / sells Nanni things / but the copper's bad, / He simply records his complaint for all time / "I got a bad deal / I'm maaaaad"
}}

==Explanation==
{{incomplete|Created by a STONE BOT WITH COPPER VENEER - Please change this comment when editing this page. Do NOT delete this tag too soon.}}
Cueball is singing a song, beginning with the words from "{{w|My Favorite Things (song)|My Favorite Things}}", which begins "Raindrops on roses and whiskers on kittens/Bright copper kettles and warm woolen mittens". But instead of the actual words, he instead notices that his copper kettles are "flaking" off. He complains about Ea-nasir, referencing the {{w|complaint tablet to Ea-nasir}}, the earliest known complaint.

The title text continues to the middle of the song, which is this: "When the dog bites/When the bee stings/When I'm feeling sad/I simply remember my favorite things/And then I don't feel so bad".

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}

:[Cueball is standing between a small rosebush and a kitten.]
:Cueball (singing): Raindrops on roses and whiskers on kittens

:[Cueball is now wearing mittens and holding a teakettle with flakes falling off it. The kitten is looking up at him. There is another teakettle on the ground next to the rosebush.]
:Cueball (singing): Bright copper kettles leave ...flakes on my mittens!?

:[Cueball has turned the teakettle he's holding upside down and is examining it. More flakes are falling off of it.]
:Cueball (singing): Hey, these are stone with a copper veneer!

:[Cueball is holding his hands out, still wearing the mittens. The two teakettles are next to each on the ground by the rosebush. The kitten is looking up at him again.]
:Cueball (singing): I've been bamboozles by Ea-nāṣir!

{{comic discussion}}
[[Category:Music]]
[[Category:Comics featuring real people]]
[[Category:Songs]]

2756: Qualifications

2023-03-30T05:31:47Z

172.71.254.100: /* Explanation */

{{comic
| number = 2756
| date = March 29, 2023
| title = Qualifications
| image = qualifications_2x.png
| imagesize = 265x316px
| noexpand = true
| titletext = 'So how DID you go from working at the employment records office to becoming president of MIT and CEO of IBM?' 'I guess I just have an eye for opportunities.'
}}

==Explanation==
{{incomplete|Created by a 600-YEAR-OLD BOT waiting for a child to be born to accept its work history - Please change this comment when editing this page. Do NOT delete this tag too soon.}}

[[Black Hat]] is being interviewed for some unidentified position. From the conversation, it seems clear that he has used some prior access to the employment records at some employment record office to fraudulently manufacture a history of having worked there for 600 years. He also claims an additional pair of prestigious jobs, but it is unclear whether these 'facts' were entirely due to false records or, knowing Black Hat's [[498: Secretary: Part 5|other]] [[1094: Interview|interviews]], briefly true but only as a result of false representation/underhanded actions.

His interviewers are not entirely unaware of the implausibility, but seem content to have just verified the validity of the claim. The 'validation' arises from the clearly tainted information source, given the whole chain of supporting evidence that may have been falsified. This is essentially a more elaborate version of Black Hat's ploy in another interview [[125: Marketing Interview|17 years prior]].

Employers often encounter resumés that have implausibly padded experience claims. Most applicants try not to be this implausible, and few employers are so credulous as to take self-supporting lies at face value.

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}

:[Black Hat sits in an office chair. Cueball, facing him, sits on another office chair at his desk and Hairbun stands behind him. Cueball is holding documents in his hands.]
:Cueball: Impressive résumé.
:Cueball: It says that you have over '''''six hundred''''' years of experience at the employment records office? That can't be right.
:Hairbun: I thought so too, but it checks out.

{{comic discussion}}

[[Category:Comics featuring Black Hat]]
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Hairbun]]
[[Category:Job interviews]]

Talk:2745: Obituary Editor

2023-03-03T17:48:16Z

172.71.254.100:

I think it's a shame the editor wasn't playing Twister with Death. --[[Special:Contributions/162.158.34.75|162.158.34.75]] 15:55, 3 March 2023 (UTC)

I think this comic is similar to [[393: Ultimate Game]]. Anyone else agree? --[[User:Purah126|Purah126]] ([[User talk:Purah126|talk]]) 16:04, 3 March 2023 (UTC)

Is this the first xkcd character with they/them pronouns? [[User:ISaveXKCDpapers|ISaveXKCDpapers]] ([[User talk:ISaveXKCDpapers|talk]]) 17:31, 3 March 2023 (UTC)
:Nope! [[145: Parody Week: Dinosaur Comics]] came first![[Special:Contributions/172.71.254.100|172.71.254.100]] 17:48, 3 March 2023 (UTC)

Talk:2745: Obituary Editor

2023-03-03T17:47:57Z

172.71.254.100: