explain xkcd - User contributions [en]

1973: Star Lore

2024-08-25T05:20:58Z

198.41.236.148: Removed extra right bracket ()) -> ()

{{comic
| number = 1973
| date = March 28, 2018
| title = Star Lore
| image = star_lore.png
| titletext = That one is a variable star which pulses every 30 seconds. Its name comes from a Greek word meaning "smoke alarm."
}}

==Explanation==
Computers, chargers, and other electronic items often have status lights in various colors. In a dark room, these lights appear as pinpricks of light, similar to constellations. Presumably, Randall's room has many such items. This comic may be part of the [[:Category:My Hobby|My Hobby series]] in the sense that his room doesn't really look like that, rather, he claims it does for humor value. It's also not clear whether this refers to Randall's bedroom (typical US usage of "my room" refers to one's bedroom) or some other room Randall spends a good deal of time in. However, since a bedroom is generally the only room in which one might spend significant time in the dark, it seems very likely this is referring to Randall's bedroom.

The comic's narrator is explaining how some of his lights remind him of stars, which gives him an opportunity to show off his knowledge of sci-fi trivia: "The Five Sisters" could be a reference to a pentagon-shaped constellation from Isaac Asimov's book ''Foundation's Edge'', though it could not have been 'known to the ancients' since it was less than 100 years old; though it could also be a somewhat more oblique reference to the Pleiades cluster (often called the Seven Sisters). It could also refer to the cluster of 5 lights next to the speech bubble, which is reinforced by the next bubble talking specifically about the bigger red light in the cluster. Interestingly, there are some green stars. Stars might look green due to a neighbouring star, but green stars are actually impossible due to the principle of {{w|black-body radiation}}. However, green status lights on electronics are common.{{Citation needed}}

In the title text, the narrator describes his {{w|smoke alarm}} status light as a pulsing variable star. A smoke alarm (which in ''modern'' Greek is "synagermós kapnoú", whatever name might be derived from the ancient-Greek version) is a device that detects smoke, which would indicate a fire. These are commonly placed in houses as a safety precaution. Typically, many smoke alarms have a status light that blinks to assure that they are still functioning. A subtle blinking light is more clear in its (intermittent) activation than a steady one that might actually be inactive but reflecting external illumination, while a high-intensity photoemitter capable of being seen in near-direct daylight would be annoyingly bright when the lights are off at night.

==Transcript==
:[A black panel with 31 dots of different sizes and in various colors (white, red, yellow, blue and green). These bright dots are scattered around three white speech bubbles for off-panel speakers. Next to the top left corner of the first bubble, there are five dots close together. Two white, two yellow (one brighter than the other) and a red dot that is clearly larger than any of the other four.]
:Person 1 (off panel): That cluster was known to the ancients as the Five Sisters.
:Person 1 (off panel): The red one is a supergiant and will probably explode within the next million years.
:Person 2 (off panel): Wow!

:[Caption below the panel:]
:There are too many status LEDs in my room.

{{comic discussion}}

[[Category:Comics with color]]
[[Category:Astronomy]]
[[Category:Computers]]

2856: Materials Scientists

2023-11-22T11:13:23Z

198.41.236.148: /* Explanation */ It's now "fixed"

{{comic
| number = 2856
| date = November 17, 2023
| title = Materials Scientists
| image = materials_scientists_2x.png
| imagesize = 296x445px
| noexpand = true
| titletext = If a materials scientist gives you a present, always ask whether regifting will incur any requirements for Federal paperwork.
}}

==Explanation==
{{incomplete|Created by a BIOLUMINESCENT DEPLETED URANIUM WRAPPING PAPER GIVING OFF A BIT TOO MUCH CHERENKOV RADIATION- Please change this comment when editing this page. Do NOT delete this tag too soon.}}

{{w|Materials science}} is essentially the study of materials, like {{w|steel}}, including some pretty strange ones such as {{w|Vantablack}} and {{w|triiodide}}. Here Ponytail and White Hat have given Cueball (a materials scientist) some sort of present. Cueball is amazed with the wrapping paper and tape itself, trying to make out what they are all made of. The caption reveals that the cardboard box is empty and the wrapping paper ''is'' the present; as a materials scientist, Cueball is more enamored by the (strange and exotic) wrapping paper, far more than he would be by any actual present inside.

The punchline also compares Cueball to a cat. A common stereotype ([https://www.reddit.com/r/funny/comments/8zw63a/thanks_for_box_human_oh_and_the_cat_tree_it_came/ with lots of image proof, to boot]) about domestic housecats is how they enjoy playing with empty boxes and discarded wrapping paper much more than the cat toys contained therein.

{{w|Aramid}} fibers (originally misspelled as "amarid" in the comic) are a class of strong synthetic fibers, built from aromatic rings connected via amide linkages. {{w|Kevlar}}, a material commonly and perhaps most famously used as a [https://youtu.be/gPKbOrxgx-w bullet-resistant fabric for] {{w|Bulletproof vest#Soft armor|soft bulletproof vests}}, is an example of an aramid. Due to their strength, they can be quite durable, even when thin, as depicted in the comic.

{{w|Triboluminescence}} refers to a phenomenon where mechanically working on a material (in this case pulling on the tape) causes it to glow. Triboluminescence is still not well understood by materials scientists, so they may find such materials particularly appealing. One famous example comes from crushing Wint-O-Green Lifesavers mints, which creates [https://youtu.be/tW8q_JfmcbU particularly bright blue sparks] compared to other hard candies. Staying in the realm of wrapping, Scotch tape exhibits this property too, [https://www.technologyreview.com/2008/10/23/217918/x-rays-made-with-scotch-tape/ to a point where it can even be used as an x-ray]. Phosphors, not to be confused with the element {{w|Phosphorus}}, are substances that glow when exposed to some other, typically more energetic, form of radiation, and can be used to produce a desired glowing effect by taking less useful parts of the spectrum (e.g. beyond the visible, or in an unnecessary area of the visible one) and shifting that into more practical hues.

{{w|Structural coloration}} is a phenomenon where the coloration of an animal or plant is not produced via pigments but via structural interactions with visible light at the scale of a wavelength (e.g. diffraction gratings, thin-film interference). More generally, it can also be used to refer to artificial materials that have a similar effect.

The title text states that if a materials scientist gives you a gift, you should ask if regifting it requires any form of federal paperwork. This is because the materials scientist may have access to items which are dangerous and strictly regulated, such as {{w|polonium}} (an extremely radioactive element), {{w|fluoroantimonic acid}} (the strongest acid discovered), {{w|nitrogen triiodide}} (one of the most sensitive explosives in the world), and {{w|n-butyllithium}} (an extremely flammable, pyrophoric, and caustic compound).

==Transcript==
:[Ponytail and White Hat are standing on the left side of a small table looking at Cueball. He stands on the other side of the table holding a gift wrapped in paper with thick black stripes. He is trying to open the gift. On the table lies two gift on top of each other. The bottom is thin and the wrapping paper has thin black stripes on it. The top present is a white box with a thick black ribbon around it and a large bow on top.]
:Cueball: Where is this wrapping paper from? It's so thin, but I can't tear it. Is this amarid fabric?!
:Cueball: Maybe I can unpeel the... oooh, the tape flashes as I pull it up! Triboluminescence! Did you add a phosphor? It's so bright!
:Cueball: Wait, are these patterns structural coloration?

:[Caption below the panel:]
:Materials scientists are like cats- the best present you can get them is an empty box with cool wrapping paper.

{{comic discussion}}

[[Category:Comics featuring Ponytail]]
[[Category:Comics featuring White Hat]]
[[Category:Comics featuring Cueball]]
[[Category:Science]]

Talk:2856: Materials Scientists

2023-11-22T11:11:06Z

198.41.236.148:

It isn't "amarid", it's "[https://en.wikipedia.org/wiki/Aramid aramid]"... -- [[User:Dtgriscom|Dtgriscom]] ([[User talk:Dtgriscom|talk]]) 03:03, 18 November 2023 (UTC)
: Sounds like a great case for a "Trivia" section below the transcript. [[User:Ianrbibtitlht|Ianrbibtitlht]] ([[User talk:Ianrbibtitlht|talk]]) 23:19, 18 November 2023 (UTC)

Damn, I'd love some gift wrap like that, it sounds fascinating, and I'm not even a materials scientist. [[Special:Contributions/172.70.130.91|172.70.130.91]] 08:29, 18 November 2023 (UTC)

Whoever added "This comic may also be an example of nerd sniping." should have said what the "nerd sniping" is that they detect here. Giving us terms to look up? Certainly not the spelling error, that's just a simple mistake. "Looking up" doesn't seem like enough to qualify, it should to be a problem to figure out, a solution begging to be found. I'll give it some time, but if I don't see this claim properly expanded I'll remove it next time I'm here. [[User:NiceGuy1|NiceGuy1]] ([[User talk:NiceGuy1|talk]]) 06:32, 19 November 2023 (UTC)

When I was in high school chemistry way back in 1960 or so, we used to make Nitrogen Triiodide. It is extremely easy to make — put some crystals of iodine in a filter paper in a funnel. Pour ammonia over them. Let dry — often the triiodide will explode as it dries. If scattered on the floor, it will explode if someone steps on it. The explosion is accompanied by a puff of purple smoke.
[[Special:Contributions/172.70.135.17|172.70.135.17]] 12:02, 20 November 2023 (UTC)

Is there any relationship between Materials Scientists and {{w|Material Girl}}s? --[[Special:Contributions/188.114.102.34|188.114.102.34]] 16:29, 20 November 2023 (UTC)
:Well, they're both living in a Material World.[[Special:Contributions/172.69.195.174|172.69.195.174]] 16:24, 21 November 2023 (UTC)

Is anyone else getting a HUGE image for this comic? It's showing up as a 4437 × 6680 pixels, 1200DPI, RGB image too big for the browser. I had to "open image in another tab" to view the whole thing. For comparison, the next comic is only 328 × 437 pixels, 80DPI, Gray. [[Special:Contributions/162.158.146.233|162.158.146.233]] 04:47, 22 November 2023 (UTC)
:Yeah, same issue here with the dimensions. It wasn't showing up that way when it was first posted, either. [[Special:Contributions/172.71.147.130|172.71.147.130]] 09:31, 22 November 2023 (UTC)
::Probably he reuploaded with a correction from "amarid" to "aramid" [[Special:Contributions/198.41.236.148|198.41.236.148]] 11:11, 22 November 2023 (UTC)