explain xkcd - User contributions [en]

Talk:2810: How to Coil a Cable

2023-08-04T08:40:19Z

162.158.111.19: /* White Hat presents the well-coiled cable */ new section

I don't actually know what name of 'coiling' it has, but the way I was taught to coil an AV cable (by an AV technician), and these days mostly use with long (garden-mower) power extensions, was ''maybe'' the 'quarter-turn' - though it's not a quarter, so maybe not - in finger-rotating the latest "end of loop" around the axis of the cable to leave it effectively twistless in its looped form (whilst introducing a 'one twist per loop-so-far' longitudinal twist in the still trailing unlooped cable that easily 'rolls-out' as you progress towards the free end/drag the length towards you). Done right, it's like smoothly 'drum-winding' the cable. But you ''can'' over-/under-twist the cable (especially if it has an internal/inherent twisting, like those christmas lights probably have with probably two entwined single-cores) so you may need to keep an eye on the multiloop you're forming and backtrack a bit if it looks like it's starting to figure-of-eight from the combined helical forces. But tricky to get perfect, may have a bit of a loop-twist (that only stays untangled due to it being ultimately hung on a hook). Maybe I've just not been taught the right methods by a powercord expert. [[Special:Contributions/172.70.90.20|172.70.90.20]] 19:39, 2 August 2023 (UTC)

: That first method is pretty much how I was taught by a guy with rather expensive microphone cables. It really does help the cable to last longer, since it's not stored with a twist. As a bonus, coiling a rope or extension cord this way also lets you throw it without it tangling in midair. Just make sure to hold onto/step on the non-thrown end... [[Special:Contributions/108.162.237.142|108.162.237.142]] 20:12, 2 August 2023 (UTC)

: I don't think they're meant to be Christmas lights. The lumpy bits that look a bit like lights are, I think, meant to be knots in the cable. [[Special:Contributions/172.70.210.148|172.70.210.148]] 15:45, 3 August 2023 (UTC)

Another profession that deals with hose/cable managment is nursing (e.g. in operating room). Don't know if they have any techniques distinct from those in the mentioned professions. [[Special:Contributions/172.69.135.82|172.69.135.82]] 21:50, 2 August 2023 (UTC)

Still wondering how topology factors into this... as of this comment, there's no explanation. - [[Special:Contributions/172.70.130.234|172.70.130.234]] 22:38, 2 August 2023 (UTC)

:Probably referencing [https://en.wikipedia.org/wiki/Knot_theory Knot Theory]. [[Special:Contributions/141.101.76.97|141.101.76.97]] 23:17, 2 August 2023 (UTC)

As a sailor once explained to me, the AV method (over/under) can potentially form a clove hitch around one's ankle while on deck, hence their use of figure-8. Meanwhile, there's another technique espoused by the likes of 'Essential Craftsman' where you basically use a chain stitch to hold it all together. [[User:Nayhem|Nayhem]] ([[User talk:Nayhem|talk]]) 00:35, 3 August 2023 (UTC)

:I have a flat extension cord that was stored for some years using the "chain stitch" method. I ended up hanging the center of the cord from my garage ceiling for a week to get the worst of the kinks out, then wound it around a 5-gallon bucket to try to flatten it out some more. For the sake of your cables, DON'T use the chain stitch method!

This sentence makes absolutely no sense to me:

: ''... alternating each obvious helix loop with a backhand loop (backwards helix turn) where the loop curls the same way as the other loops, but its 'helix height' is backwards ...''

I think I need an "Explain Explain xkcd"... 😕 [[User:IMSoP|IMSoP]] ([[User talk:IMSoP|talk]]) 10:03, 3 August 2023 (UTC)

The idea of enlisting the help of an "expert" reminds me of how my father would always have the best charcoal barbecue at the picnic site. He would bring the charcoal and lighter to the picnic area and then walk around to see what everyone else's barbecue looked like. When he identified the best burning site, he would would walk over to the barbecue master and say to that person something like, "Excuse me, I really admire how your fire is burning, my kids are over there and I'm a little embarrassed that I don't really know how to do this. Could you show me how you got such a great fire?" The expert was always willing to build the fire for him. That's how, time after time, we always had a great burning barbecue.{{unsigned}}

My reading of the comic was different to what's currently in the explanation. I read it as Cueball has just uncoiled the cable ready for use, and is annoyed at all the kinks and tangles that have resulted from it having been coiled up. The others are then so keen to demonstrate how to do it better, that they end up coiling it all back up again, which doesn't actually help him in the slightest. Which seems funnier to me. [[Special:Contributions/172.70.211.190|172.70.211.190]] 15:34, 3 August 2023 (UTC)

There is some controversy over "flake" vs "fake", see https://tradewindssailing.com/wordpress/?p=1343 for example. I learned "fake," the comic uses "flake." IDK.

== Methods explained ==

The over-over(quarter turn twist)

The over-under
https://youtu.be/JtOGJZ_gYy8
https://youtu.be/cpuutP6Df84

Chain technique
https://youtu.be/L7av0C0jWQw

See also https://people.maths.bris.ac.uk/~majge/hjce.06.pdf "Knotting probability of a shaken ball-chain" [[Special:Contributions/172.70.251.170|172.70.251.170]] 10:08, 3 August 2023 (UTC)

== White Hat presents the well-coiled cable ==

“Neatly coiled!” doesn’t look like a speech bubble, but more like an annotation bubble—it uses an arrow instead of a simple line. Thus it is not a “White Hat presents”, but the final step in this tutorial.--[[Special:Contributions/162.158.111.19|162.158.111.19]] 08:40, 4 August 2023 (UTC)

1032: Networking

2018-10-03T08:58:15Z

162.158.111.19:

{{comic
| number = 1032
| date = March 21, 2012
| title = Networking
| image = networking.png
| titletext = Our company is agile and lean with a focus on the long tail. Ok, our company is actually a polecat I found in my backyard.
}}

==Explanation==
Obviously, [[Beret Guy]]'s [[1021|business plan]] worked.

Networking, in business, is the act of expanding your group of contacts in order to help your career down the line. Here, in this comic, [[Beret Guy]] meets Chief Technology Officer (CTO, an executive level position overseeing development of new technologies) Connr Clark (perhaps a typo for "Connor" or perhaps a reference to common "Web 2.0" names like the businesses {{w|Flickr}}, {{w|Tumblr}}, etc.) and Beret Guy is as strange as he usually is: he introduces himself as a "business professional" rather than as someone with any kind of specific job, and then goes on to mention that he photocopied a burrito, which he presumably believes is the sort of thing business professionals do. He also has a business card; usually this would contain contact information, but his only says "This is my business card". He calls his briefcase, or suitcase, a "handlebox", and it is full of a quarter of a million dollars in cash. Then Beret Guy proceeds to eat Connr's business card. All of these things are not common behavior.

"Networking" is often an over-hyped, empty affair. There are zillions of networking meetings of every description going on every day everywhere, and mostly people trade cards and continue to not make money. So that's the joke – Beret Guy does the networking {{w|schtick}}, badly, and yet is somehow making huge amounts of money at it.

The comic is also likely a joke on the idea that many people are excited about becoming a "business professional" who carries a briefcase, hands out business cards, and makes tons of money, without having an adequate plan for how to make those things happen, or possibly even knowing what their actual job would be. Beret Guy never says what he does, simply introducing himself as a "business professional," and explains his piles of cash with "I am a business grown-up who makes business profits!" In this world —and in people's dreams— when you "grow up" and start a business, money magically appears. Obviously, that's not how it works.

The "Eusocial" in "Eusocial Media Ventures" is a reference to {{w|eusociality}}, the highest level of social cooperation found in the animal kingdom. Eusocial animals (termites being a common example) cooperate together to raise their young, have different generations living in the same colony, and have specialized individuals for reproductive and non-reproductive tasks.

The title text is a pun on three common business buzzwords: agile, lean and long-tail. An agile business is one that can change course quickly based on customer demands and the business environment. A lean business is one with minimal inventory or assets; nothing is idle or warehoused, so everything in active use or on the move. Long-tail describes the strategy of offering a large number of unique items with relatively small quantities sold of each – usually in addition to selling fewer popular items in large quantities. Netflix is a popular example of long-tail because they have (almost) every movie imaginable, including rare titles that only a few people would be interested in.

And of course, the pun here is one animal that is agile and lean with a long ''tail'' is a {{w|polecat}}.

Furthermore, although "agile" and "lean" do mean a quick, nimble, and efficient business, they also refer to specific practices, as in {{w|agile software development}}, {{w|lean manufacturing}} and {{w|lean Six Sigma}}. Many people think these terms have devolved to overused jargon. While agile development is supposed to be a highly structured method to get programmers to produce more working code quickly, when someone from the marketing department says "''agile''" it often means "''We don't know what we're supposed to be producing, so we'll just chuck some stuff together, and keep those bits that the customer says he likes. We'll then do it all over again until we've got something that he'll pay for.''" "''Lean''" is supposed to mean that a business keeps its costs as low as possible, employing one person to do marketing and PR, not really having a Human Resources department, etc. But, in practice it often becomes "''Keep as little stock as possible so that we don't have a lot of money tied up in it, and don't need a big warehouse; make stuff just before it is supposed to ship so that we don't have to store it either; make frequent prayers and virgin sacrifices to whatever gods we can find to ensure that nothing slips up anywhere along the line that our lawyers can't get us out of.''"

See also [[1117: My Sky]].

==Transcript==
:[A man approaches Beret Guy at a party and they extend arms to shake hands. Beret Guy is holding a metal briefcase. Ponytail is a waitress in the background, carrying a tray with a wine glass on it.]
:Connr: I'm Connr Clark, CTO at Eusocial Media Ventures.
:Beret Guy: I'm a business professional! Earlier I photocopied a burrito!

:[Connr hands Beret Guy a business card. Beret Guy takes it and hands Connr another business card. Beret Guy has put his suitcase on the floor.]
:Connr: You should check us out! Here's my card.
:Beret Guy: Here's mine! Networking!

:[Connr takes a closer look at the card, and Beret Guy holds up his case.]
:Connr: ...this just says "This is my business card!"
:Beret Guy: Do you like it? I have more in my handlebox.

:[Beret Guy puts his case on a table and opens it to reveal it is full of cash. Connr looks on in shock.]
:Connr: Uh, that's ok, I think I'll—
:Beret Guy: Here, have ten of them!
:Connr: —holy shit that thing is full of ''cash!''

:[Connr raises his arms in excitement. Beret Guy turns to face him and chews on Connr's business card.]
:Connr: Where did you ''get'' that?
:Beret Guy: I am a business grown-up who makes business profits!
:Connr: That's like a quarter of a million dollars!
:Beret Guy: Yay! Business is fun! Do you have more of your cards? They're ''delicious!''

{{comic discussion}}
[[Category:Comics with color]]
[[Category:Comics featuring Beret Guy]]
[[Category:Comics featuring Hairy]]
[[Category:Beret Guy's Business]]
[[Category:Comics featuring Ponytail]]

969: Delta-P

2018-09-24T19:37:58Z

162.158.111.19: /* Explanation */

{{comic
| number = 969
| date = October 26, 2011
| title = Delta-P
| image = delta p.png
| titletext = If you fire a Portal gun through the door of the wardrobe, space and time knot together, which leads to a frustrated Aslan trying to impart Christian morality to the Space sphere.
}}

==Explanation==
''{{w|The Lion, the Witch and the Wardrobe}}'' is a book in which four children accidentally wander into a world known as {{w|Narnia}} through a wardrobe that only allows passage through to Narnia when you aren't looking for it. In the comic, someone connects an anchor to the wardrobe and throws it into the ocean. The formula describes the flow of water through the open doors when the wardrobe sits at the bottom of the ocean in 2 km depth, which means that a steady stream of water at an approximate velocity of 200 meters per second will flow into Narnia.

The evil {{w|White Witch}}, who has made it [http://www.goodreads.com/quotes/93155-always-winter-but-never-christmas "always winter, and never Christmas,"] could not have anticipated that a wardrobe portal would suddenly begin spewing approximately 400,000 liters of water per second into Narnia.{{Citation needed}}

Sea water freezes at low temperatures and flowing water freezes at even lower temperatures, depending how fast it is going. Water jetting out from this portal would be flowing very quickly indeed, approximately 200 meters per second (450 mph or 720 km/h) as the comic says; this is over half the speed of sound. And the water flow is approximately 400,000 liters per second, again, provided in the image above. The force of this water jet would be incredible. If you can imagine the force of a tractor trailer truck careening down the highway, the force of this jet is much much larger than that.

This water would not freeze. First it would decimate any forest trees or iron lamp posts in front of it until it eventually slowed down and fell to the ground. There it would create a rapidly expanding river of sea water. Narnia would not stay frozen for long. Snow would melt, ice would break apart and the valley would quickly flood.

Delta-P is a mathematical term for the difference in pressure. The shown formula is based on the {{w|Hagen–Poiseuille equation}} which can be applied to a flowing liquid in a long cylindrical pipe; thus the equation here results in an unphysically high flow rate because the opening is rectangular and too short for a {{w|Laminar flow|laminar flow}}. Using the ''Hagen–Poiseuille equation'' the maximum flow rate is given by:
:<math>Q_\max{} = \pi R^2 \sqrt\frac{2 \Delta P}{\rho}</math>
:<math>\pi R^2</math> is the pipe cross-sectional area (m2) and <math>\rho</math> is the fluid density (kg/m3).
From the {{w|Hydrostatics|hydrostatics}} of water the pressure difference depends on gravity and the height:
:<math>\Delta P = \rho g h,</math>
:<math>g</math> is the gravitational acceleration (m/s2) and <math>h</math> is the height (m).
Putting this together and changing the cross-sectional area to a rectangular area <math>A</math> we get the formula used by Randall:
:<math>Q_\max{} = A \sqrt{2 g h}</math>
Assuming the wardrobe is two meter high and one in width (''A = 2 m2'') and using the gravitational constant ''g = 9.81 m/s2'' the flow rate is 396 m3 per second, or roughly 400.000 liters per second.
The water jet velocity ''v'' is based on {{w|Torricelli's law}}:
:<math>v=\sqrt{{2 g}{h}}</math>
It gives 198 m/s in this scenario.

The title text references the video game ''{{w|Portal (video game)|Portal}}'' in which you solve puzzles using a gun which projects portals onto certain surfaces. In the game you cannot shoot a portal through a portal, but [[Randall]] says that if you try to create a portal with the portal gun through the wardrobe, space and time knot together. {{w|Aslan}} is a lion and a main character in C. S. Lewis's ''{{w|The Chronicles of Narnia}}'' series and represents Jesus Christ. The Space Sphere is a minor character in the game ''{{w|Portal 2}}''; it is a barely-sentient AI whose only preoccupation is going to space, and it would not be receptive to Aslan's teachings.

==Transcript==
:[An open wardrobe, with a boat anchor attached to one corner, falling towards water.]
:[Below the water line a formula with its variables explained is shown:]
:Q = A * sqrt(2 * g * d)
:Q = flow rate
:A = area of opening
:d = ocean depth (2 km)
:g = Earth gravity

:[And below the formula:]
:Flow: ~400,000 liters/s
:Water jet velocity: ~200 m/s

:[Caption below the frame:]
:The White Witch didn't know what hit her.

{{comic discussion}}
[[Category:Comics with color]]
[[Category:Physics]]
[[Category:Video games]]
[[Category:Fiction]]
[[Category:Chronicles of Narnia]]

Talk:1818: Rayleigh Scattering

2017-03-31T16:41:59Z

162.158.111.19: agreement

I keep trying to correct the misspelled joung Girl to Young Girl but it keeps reverting. I corrected the two non-capitalized sentences and they stay put. Does "joung" have a meaning i don't understand? [[User:ExternalMonolog|ExternalMonolog]] ([[User talk:ExternalMonolog|talk]]) 14:55, 31 March 2017 (UTC)

Question - while I understand the intent of the comic is that overly complicated explanations can be confusing, isn't the title-text analogy incorrect? Doesn't chlorophyll scatter green light and absorbs other colors, whereas with the sky, it's really just different levels of scattering and very little absorbing (hence why a clear sky at dusk can appear red, the sky wasn't absorbing red light, it was just scattering it differently than blue light). Isn't that fundamentally different from the way most other common objects get their perceived color? (ps - I'm not a scientist, just curious, appreciate any feedback)

:There might be conflicting edits, that happens a lot with new comics[[User:Dontknow|Dontknow]] ([[User talk:Dontknow|talk]]) 15:34, 31 March 2017 (UTC)

"Why are leaves green?" "Well, the leaf absorbs most of the colors, but not the green light, which it scatters instead." "Why is my shirt black?" "Well the cloth absorbs most of the colors, but just scatters the black light... wait..." [[User:Andyd273|Andyd273]] ([[User talk:Andyd273|talk]]) 15:46, 31 March 2017 (UTC)

I like to think this is Miss Lenhart, continuing her science teaching in the same vein as in 'Venus'. There's no proof in the comic, but it fits nicely. Potentially something to add as a possibility in the explanation? [[Special:Contributions/162.158.154.247|162.158.154.247]] 16:38, 31 March 2017 (UTC)
ht... wait..." [[User:Andyd273|Andyd273]] ([[User talk:Andyd273|talk]]) 15:46, 31 March 2017 (UTC)

Yesssss <3 I had the exact same thought the first time Rayleigh scattering was explained to me: "isn't that just a specific mechanism of air being blue?" For some reason such explanations majorly tend to insist that the air is not in fact blue, and it has always bothered me. [[Special:Contributions/162.158.111.19|162.158.111.19]] 16:41, 31 March 2017 (UTC)