explain xkcd - User contributions [en]

Talk:2913: Periodic Table Regions

2024-03-30T12:39:03Z

172.70.85.141:

Working on the table catalog. For ones that are part of multiple groups, I used the one that takes up the most. For split ones like Mn, I put them both. For Cs, please don't change it because Randall's American and that's how he would think of it. I know what all the elements are so please don't edit conflict me. --[[User:Purah126|Purah #126]] ([[User talk:Purah126|talk]]) 20:50, 29 March 2024 (UTC)

:I'm done. Again, please don't have an edit war over cesium and aluminum. --[[User:Purah126|Purah #126]] ([[User talk:Purah126|talk]]) 20:50, 29 March 2024 (UTC)
::What about Hahnium? ;) [[Special:Contributions/172.70.163.31|172.70.163.31]] 20:54, 29 March 2024 (UTC)
:::That's only for some people in Berkeley, if someone can find evidence that he's used it before in a comic then sure lol. --[[User:Purah126|Purah #126]] ([[User talk:Purah126|talk]]) 21:12, 29 March 2024 (UTC)
::::At times, dubnium, hassium, meitnerium ''and'' darmstadtium were considered for naming after Otto Hahn, and it reached several stages of international deliberation.
::::I actually learnt my chemistry in a (UK) lab with a wall-poster periodic table that had Hahnium shown on it. But I can't quite remember in what position, nor can I remember enough of the other differences (there being several) from the actual 'official' namings, so cannot be sure exactly what provenance it had. Pre '92, though, which rules out some of the options.
::::...but memorable enough for me to 'keep an eye out' for the fate of the name in later years. [[Special:Contributions/172.69.43.243|172.69.43.243]] 21:56, 29 March 2024 (UTC)

What about the two categories implied by "Ends in a number, let it slumber. Ends in a letter, not much better"? Which elements are in which? -- [[User:Dtgriscom|Dtgriscom]] ([[User talk:Dtgriscom|talk]]) 01:36, 30 March 2024 (UTC)
:I'd say "all in both". Any given "fooium" is going to be a reactive element that (especially as you go further down) is nasty to deal with 'raw'. But not as nasty as "fooium-123", which highly suggests a nuclear decay product that will further decay. [[Special:Contributions/172.71.178.218|172.71.178.218]] 02:39, 30 March 2024 (UTC)

Correcting some errors in the stuff about radon led me to add perhaps too much information about how it's formed, how it accumulates in basements, and how it causes health problems. I spent a few years in a lab whose primary research focus was on uranium mine waste and its consequences, so I've got some bias and blind spots. Others may want to edit it down. [[User:BunsenH|BunsenH]] ([[User talk:BunsenH|talk]]) 01:39, 30 March 2024 (UTC)
:FWIW, the idea that radon collects in basements because of its density is a myth. It mixes with air; any variation with altitude is negligible, just as xenon and CFCs don't collect at low altitudes. [[User:BunsenH|BunsenH]] ([[User talk:BunsenH|talk]]) 04:42, 30 March 2024 (UTC)

I'm too lazy to add this myself, but should there be something in the explanation about the overlap between "weird metals" and "murder weapons? (I checked over it quickly, correct me if there is already something about it) EDIT - just realized this could be due to mercury being in "murder weapons" - Thexkcdnerd 02:02, 30 March 2024 (UTC)

There should be a comment on the fact that people have included that last row inside the table, [such as here](https://en.wikipedia.org/wiki/Extended_periodic_table#Predicted_structures_of_an_extended_periodic_table). It makes it really long, but there's a pretty basic pattern you can extend endlessly. Every other row, you lengthen it by four more than the previous pairs of rows. Though I understand the way orbitals work that make that useful doesn't really apply after you get too far down. [[User:DanielLC|DanielLC]] ([[User talk:DanielLC|talk]]) 03:23, 30 March 2024 (UTC)
:That has been done (not by me), now. But I also added (along the way) something about how not all PTs actually shift La and Ac out of the table. Though, honestly, I actually find it darn unusual (in my experience) to do that, often with those two under Sc and Y, and then the 'floating' groups go from up to Lu and Lr, ''perhaps'' starting with a 'repeat hint' of the eponymous elements, then Ce and Th. Otherwise, a split indicated between Group 2 and 3 and the two 14-long sets (La to Yb and Ac to No) with Lu and Lr group-3ed (more accurate to f-block?).
:Actually just overturned a few piles of books to try to find my old (30+ years!) degree-level material to confirm what exactly I recall working with back then, but they're probably stashed away elsewhere. Contemporary online versions do all kinds of things, sometimes seemingly according to abstract whims and clearly there's still no 'official' concensus... Hence I left it at "not all" doing so. [[Special:Contributions/172.70.85.27|172.70.85.27]] 09:33, 30 March 2024 (UTC)
::I mean, "Lanthanide" means "Lanthanum-like". Is lanthanum like itself? It either very definitely is, pretty much pefectly,{{Citation needed}} or it really isn't ''like'' it, for the same reason... (But, whatever the answer, we should probably say that actinide is the opposite for the actinides. To satisfy everyone!) [[Special:Contributions/172.70.85.141|172.70.85.141]] 12:39, 30 March 2024 (UTC)

2911: Greenland Size

2024-03-27T09:24:10Z

172.70.85.141: /* Explanation */ Not necessarily easy, for the mathematically challenged (especially if in non-metric units)

{{comic
| number = 2911
| date = March 25, 2024
| title = Greenland Size
| image = greenland_size_2x.png
| imagesize = 262x304px
| noexpand = true
| titletext = The Mercator projection drastically distorts the size of almost every area of land except a small ring around the North and South Poles.
}}

==Explanation==
{{incomplete|Created by a GREEN LAND FOR ANTS - Please change this comment when editing this page. Do NOT delete this tag too soon.}}
Because the {{w|Earth}} is curved, all flat maps have some distortion. (A common comparison is flattening an orange peel, which cannot be done without tearing and wrinkling it.) Different {{w|map projection}}s can distort different {{w|Map projection#Metric properties of maps|metric properties}}, such as distances, areas, and angles, while leaving others intact. It can be desirable to preserve different metrics in different applications.

The {{w|Mercator projection}}, depicted in the comic, prioritizes depicting correct angles. This allows for easy course planning at sea, and makes shapes fairly accurate. In exchange, Mercator is often criticized for distorting size: distances near the poles look larger than the same distance near the {{w|equator}}. A common complaint is that {{w|Greenland}} appears as big on the map as {{w|Africa}}, when Africa actually has 14 times as much area as Greenland. When these size distortions are presented out of context, they can create bias and misconceptions about different places.

[[Cueball]]'s dialogue leads the reader to expect this complaint. However, instead of comparing ''relative'' sizes of two landmasses within the map, [[Cueball]] compares the ''absolute'' sizes of the depiction of Greenland and the actual Greenland. On a typical world map, Greenland might be centimeters or inches across. Judging from the human characters, the mapped Greenland in this comic might be 10 cm across. In real life, Greenland is about 650 miles or 1,050 km across from east to west ([//britannica.com/place/Greenland source]). Cueball deems this difference misleading, presenting it as a failure of this specific map or projection.

Of course, this is absurd. The purpose of any map is to present information much more compactly so that it is easy to read and interpret. Any actual-size world map would have to be the size of the Earth's surface, in which case it would have few uses. In addition, if a map includes a {{w|Scale (map)|scale}}, it enables the user to use the ratio to calculate the actual size of the places depicted.

The title text is about the fact that a horizontal line on a worldwide Mercator projection corresponds to a line of latitude. Most lines of latitude are thousands of miles (kilometers) long, but they become smaller and smaller approaching the poles, and in fact there ''is'' a line of latitude in a small-diameter circle around each pole whose length would equal the width of the map that Cueball is looking at. If Cueball's map were 1 m wide, then this line of latitude would be at 89.999998568° N or S - that is, the line of latitude there would be a circle with a circumference of 1 m around each of the poles.

A map at a scale of 1:1 was discussed in {{w|Lewis Carroll}}'s "{{w|Sylvie and Bruno Concluded}}":

<blockquote>
''"What a useful thing a pocket-map is!" I remarked.'' 
''"That's another thing we've learned from ''your'' Nation," said Mein Herr, "map-making. But we've carried it much further than ''you''. What do you consider the ''largest'' map that would be really useful?"'' 
''"About six inches to the mile."'' 
''"Only ''six inches''!" exclaimed Mein Herr. "We very soon got to six ''yards'' to the mile. Then we tried a ''hundred'' yards to the mile. And then came the grandest idea of all! We actually made a map of the country, on the scale of ''a mile to the mile''!"'' 
''"Have you used it much?" I enquired.'' 
''"It has never been spread out, yet," said Mein Herr: "the farmers objected: they said it would cover the whole country, and shut out the sunlight! So we now use the country itself, as its own map, and I assure you it does nearly as well."''
</blockquote>

The same idea was expanded in {{w|Jorge Luis Borges}}'s "{{w|On Exactitude in Science}}".

Mercator projections have been mentioned previously in [[977: Map Projections]], [[2082: Mercator Projection]], and [[2613: Bad Map Projection: Madagascator]].

==Transcript==

:[Cueball and White Hat are looking at a world map on the wall showing a Mercator projection, with Cueball gesturing with his hand towards the map.]
:Cueball: This map is really misleading about the size of Greenland.
:Cueball: It's actually '''''much''''' bigger than that - it's hundreds of miles across.

{{comic discussion}}

[[Category:Comics featuring Cueball]]
[[Category:Comics featuring White Hat]]
[[Category:Maps]]
[[Category:Geography]]