https://www.explainxkcd.com/wiki/api.php?action=feedcontributions&user=162.158.203.10&feedformat=atomexplain xkcd - User contributions [en]2024-03-29T15:04:33ZUser contributionsMediaWiki 1.30.0https://www.explainxkcd.com/wiki/index.php?title=2649:_Physics_Cost-Saving_Tips&diff=2905422649: Physics Cost-Saving Tips2022-07-24T19:43:31Z<p>162.158.203.10: Undo revision 290535 by Davidy22 the tranny killer (talk)</p>
<hr />
<div>{{comic<br />
| number = 2649<br />
| date = July 22, 2022<br />
| title = Physics Cost-Saving Tips<br />
| image = physics_cost_saving_tips.png<br />
| titletext = I got banned from the county fair for handing out Helium-2 balloons. Apparently the instant massive plasma explosions violated some local ordinance or something.<br />
}}<br />
<br />
==Explanation==<br />
{{incomplete|Created by a FAUX VECTOR - Please change this comment when editing this page. Do NOT delete this tag too soon.}}<br />
<br />
This comic is another one of [[Randall|Randall's]] [[:Category:Tips|Tips]], this time to reduce costs or provide something for free for physicists to save money on their research. None of these would provide any real advantages even when possible to implement. It continues the previous [[2648: Chemicals]] comic's jocular theme of tricks to supposedly save money based on misinterpretations of science. Obtaining money from physics experiments was also described in [[2007: Brookhaven RHIC]].<br />
<br />
{| class="wikitable"<br />
|-<br />
! scope="col" |Cost-Saving Tip<br />
! scope="col" |Explanation<br />
|-<br />
|Try replacing regular vectors with pseudovectors whenever possible<br />
|[[File:Torque animation.gif|frame|right|Relationship of pseudovectors {{w|torque}} ('''τ''') and {{w|angular momentum}} ('''L''') to "regular" Euclidian vectors {{w|Position (vector)|position}} ('''r'''), {{w|force}} ('''F'''), and linear {{w|momentum}} ('''p''') in an oscillatory rotating system. Not shown is the {{w|centripetal force}} of the spoke's {{w|Tension (physics)|tension}}, a Euclidian vector towards the axle proportional to linear momentum, converting it to angular momentum.]]<br />
<br />
The prefix "pseudo-" refers to an inauthentic variation of something. Fakes are usually cheaper than their original brand-name product, while often working just as well, so the comic implies a {{w|pseudovector}} could be a less expensive substitute for a regular vector. On the contrary, pseudovectors, or axial vectors, are distinct from regular {{w|Euclidean vector}}s, the former usually being involved with rotation or physical effects that share properties with rotation, similar to the relationship between angles and lengths. Pseudovectors are formed from the {{w|cross product}}s of Euclidean vectors, in three dimensions, and while similar to Euclidean vectors, there is no physical meaning to their specific direction, only their magnitude and portions of their position. For example, {{w|angular momentum}} is described by a pseudovector, labeled '''L''' in the comic, {{w|Normal (geometry)|normal}} to the {{w|plane of rotation}}, originating from the center of rotation, with magnitude equal to the angular velocity of rotation '''ω''' multiplied by the {{w|moment of inertia}} '''I'''. (The comic's diagram is drawn according to very uncommon {{w|Right-hand rule#Coordinates|left-handed coordinates}} instead of the standard {{w|right-hand rule}}. Randall is right-handed.[https://www.youtube.com/watch?v=j1tcyEo2tQk&t=28s])<br />
|-<br />
|A square wave can be broken down into an infinite supply of valuable sine waves<br />
|{{w|Fourier analysis}} can decompose any periodic function into a series of {{w|sine wave}}s. A {{w|square wave}} can thereby be represented as the sum of an infinite series of sine waves. However, the sine waves are not removed or separated individually, so such a {{w|Fourier transform}} does not produce a "supply" of sine waves for practical use in any tasks other than analysis, and as abstract mathematical objects exempt from the laws of supply and demand, their value is similarly limited.<br />
|-<br />
|Cut waste by buying lighter isotopes that don't have any dead-weight neutrons<br />
|Chemical elements are identified by the number of protons in each atomic nucleus, equal to the number of electrons in their shell (unless the atom is ionized), which dictates most of their chemical behavior. {{w|Isotopes}} are variants of the element with different numbers of neutrons in the nucleus, among which chemical behavior is usually nearly identical. The comic suggests that the neutrons don't serve any useful purpose, so, in theory, if purchasing an element by weight, and its isotopes have the same price per unit weight, then you can save money by buying isotopes with no neutrons at all. In reality, the cost per unit weight for material containing a larger concentration of normally rare isotopes, such as {{w|heavy water}} or {{w|enriched uranium}}, is much higher than the cost of material containing isotopes in their ordinary proportions. (An exception is {{w|depleted uranium}}, which costs less than regular uranium because it is a byproduct of the production of enriched uranium.) In addition, a certain range of neutron quantity is needed to keep atoms stable, as atoms with too many or too few neutrons will decay more quickly than the common isotopes. The image shown is helium-2, an {{w|Isotopes of helium|isotope of helium}} which has a half-life of less than a nanosecond. It decays into two ionized hydrogen atoms, releasing a large amount of energy—hence the explosions mentioned in the title text.<br />
|-<br />
|Conductors are a great source of free electrons (may carry charges)<br />
|{{w|Charge carrier|Free}} {{w|electron}}s are electrons that are not tightly bound to specific atoms so they can move freely, such as in {{w|conduction band}}s of the {{w|metallic bond}}s throughout the iron ingot depicted in the comic. Randall interprets "free" in a different sense, meaning no cost. The charges free electrons carry are electric, not monetary as implied by the pun.<br />
|}<br />
<br />
In the title text, Randall claims to have been banned from the county fair for handing out helium-2 balloons because of the instant massive explosions caused by its radioactive decay. He jokes they violated a local ordinance. Helium balloons are often given out at county fairs and similar events, but they are filled with helium-4 and therefore inert. A balloon filled with helium-2 is a practical impossibility because of its nanosecond half-life. Assuming a 12-inch diameter balloon at 1 atmosphere of pressure, the balloon-bomb would have a yield of roughly 17 {{w|TNT equivalent|tons of TNT equivalent}}.<br />
<br />
{{cot|[[User:SqueakSquawk4|Calculations]]}}<br />
{{User:SqueakSquawk4}} <!-- want to subst: this if it's okay with SqueakSquawk4 --><br />
{{cob}}<br />
<br />
The smallest nuclear bomb, the {{w|W54}}, had a yield of between 10 and 1,000 tons of TNT. The largest conventional bomb, the {{w|GBU-43/B MOAB}}, has a yield of roughly 11 tons. The {{w|2020 Beirut explosion}} was roughly equivalent to 300-1200 tons. So, while the helium-2 balloon bomb would be larger than all conventional bombs, it would still be smaller than most nukes. Handing out what are effectively small atomic bombs at a county fair would not go down well with any surviving local authorities, so merely being banned is a very mild punishment. Criminal charges such as mass murder and terrorism would be more likely if it weren't for the absurd impossibility of the scenario.<br />
<br />
==Transcript==<br />
{{incomplete transcript|Do NOT delete this tag too soon.}}<br />
<br />
:[Title]<br />
:Physics Cost-Saving Tips<br />
<br />
:[A diagramatical spinning disc, at an angle]<br />
:[It is identified with an 'I', with a dotted axial arrow labelled 'L' and a rotational movement labelled 'ω' (small omega)]<br />
:[It sits on the left, and to the right of this is text...]<br />
:Try replacing regular vectors with pseudovectors whenever possible<br />
<br />
:[A square wave with three maxima (between four minima), and arrows pointing down into a collection of five sine waves of different wavelengths]<br />
:[One of the waves having the same frequency as the square wave and the rest of them are of shorter lengths with more peaks and troughs]<br />
:[It sits on the right, and to the left of this is text...]<br />
:A square wave can be broken down into an infinite supply of valuable sine waves<br />
<br />
:[Two atomic models]<br />
:[The left containing two protons (white with a "+" sign), two neutrons (black) and orbited by two electrons (small outlines, dotted orbits/movement lines), labelled below with the text of superscript atomic weight and element symbol]<br />
:<sup>4</sup>He<br />
:[The right model has just the two protons and the two electrons, labelled below with the text of an atomic weight and elemental symbol, and some subtext within brackets]<br />
:<sup>2</sup>He<br />
:(Decays fast - use quickly)<br />
:[Both models sit on the left of the comic, and to the right is text...]<br />
:Cut waste by buying lighter isotopes that don't have any dead-weight neutrons<br />
<br />
:[A flat rectangular bar, drawn in perspective with a scattering of dots/small circles on the top face and on the forward-facing one the label]<br />
:Iron<br />
:[An arrow points to the dots, from the text...]<br />
:Free electrons<br />
:[It sits to the right, and there is text to the left...]<br />
:Conductors are a great source of free electrons<br />
:(May carry charges)<br />
<br />
{{comic discussion}}<br />
<br />
[[Category:Tips]]<br />
[[Category:Physics]]<br />
[[Category:Chemistry]]</div>162.158.203.10https://www.explainxkcd.com/wiki/index.php?title=78:_Garfield&diff=29039478: Garfield2022-07-24T04:42:25Z<p>162.158.203.10: /* Explanation */ Richard Stallman promotes free software, not open-source software</p>
<hr />
<div>{{comic<br />
| number = 78<br />
| date = March 20, 2006<br />
| title = Garfield<br />
| image = garfield.jpg<br />
| titletext = The use of the 'Garfield' character for the purposes of this parody qualifies as fair use under the Copyright Act of 1976, 17 U.S.C. sec. 107. See Campbell v. Acuff-Rose Music (92-1292), 510 U.S. 569<br />
}}<br />
<br />
==Explanation==<br />
The newspaper comic strip {{w|Garfield}}, which features an orange cat as the main character, has increasingly been known for repetitive, quality-lacking strips. In the past, this was because the creator, {{w|Jim Davis (cartoonist)|Jim Davis}}, prefers to explore the same subjects he is comfortable with but in different ways — or from a less charitable view, because the strip is intended for a wide audience and thus becomes homogenized and inoffensive by nature. This attitude has only become more pronounced in the 21st century, as the aging Davis becomes less and less interested in the franchise. Regardless of the reason, these strips are now {{w|Ghostwriter|ghost written}} with little input from Davis and rarely explore the unconventional. The comic is challenging Davis to do something unexpected and surprise us all. The comic also accuses Davis of being a "sell out", sticking to bourgeois/commercial logic, something that dadaist artists challenged.<br />
<br />
{{w|Dadaism}} was an artistic movement in the early 20th century marked primarily by chaos, irrationality, and surrealism. Some of the artists believed that the bourgeois logic made human beings unhappy and therefore led to war.<br />
<br />
Randall leads by example by featuring a strip that parodies the style of Garfield, with multiple colors (xkcd usually contains only black and white, with some few containing an additional color like red or yellow) and a character that is not a stick figure breaking the normal xkcd pattern. Another dadaist aspect is the fact that while Garfield is smiling, he is communicating something that could be considered terrifying.<br />
<br />
The title text explains that xkcd is exercising legal use of Davis's intellectual property, namely the title character of his comic. The Supreme Court case mentioned, ''{{w|Campbell v. Acuff-Rose Music}}'', confirmed that parody is legal even when there is commercial gain as a result, and also referenced the {{w|Copyright Act of 1976}}, 17 U.S.C. § 107, for the same reason.<br />
<br />
While this is normally understood by most anyone who questions such matters, [[Randall]] includes it as a reference to the lessening of strict copyright law, which many comics also mention, usually in the context of {{w|free software}} and those who promote it, like in the comics featuring [[:Category:Comics featuring Richard Stallman|Richard Stallman]].<br />
<br />
==Transcript==<br />
:I want to see something unexpected in comics. Just one strip could make up for it all.<br />
:[Garfield is standing on hind legs facing and looking directly at the camera. But is off-center in the frame, about 1/3 from the left, rotated very slightly clockwise.]<br />
:[Zoom in on Garfield, still to the left, now rotated slightly counterclockwise.]<br />
:[Zoom in again on Garfield, now the frame clips off the left side of his face.]<br />
:Garfield thought bubble: The world is burning.<br />
:[Final zoom in, the frame is ripped like a page, offset, and Garfield's eyes are half closed on the right half.]<br />
:Garfield thought bubble: Run.<br />
:Jim Davis, throw off your commercial shackles. Challenge us. Go out in a blaze of Dadaist glory. There is still time.<br />
<br />
==Trivia==<br />
*The comic number, #78, corresponds to the year Garfield debuted, 1978.<br />
<br />
<br />
{{comic discussion}}<br />
[[Category:Comics with color]]<br />
[[Category:Comics featuring real people]]</div>162.158.203.10https://www.explainxkcd.com/wiki/index.php?title=2619:_Cr%C3%AApe&diff=2735732619: Crêpe2022-05-21T17:13:45Z<p>162.158.203.10: /* Explanation */ typo</p>
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<div>{{comic<br />
| number = 2619<br />
| date = May 13, 2022<br />
| title = Crêpe<br />
| image = crepe.png<br />
| titletext = A medicine that makes you put two dots over your letters more often is a diäretic.<br />
}}<br />
<br />
==Explanation==<br />
{{incomplete|Created by a ÇRÊPË - Please change this comment when editing this page. Do NOT delete this tag too soon.}}<br />
[[File:crêpe.png|thumb|The word "crêpe" in the comic]]<br />
[[Cueball]] has made a {{w|crêpe}}, a thin pancake known for its legendary status in French cuisine, which he proudly announces. However, the {{w|circumflex}} (the accent above the e) is written strangely. Instead of the usual simple angle (^), it looks more like the outline of a flattened arrowhead (<span style="text-fill-color: transparent; text-stroke: 1pt currentColor; -webkit-text-fill-color: transparent; -webkit-text-stroke: 1pt currentColor;">⮝</span>). [[Megan]], who can apparently {{tvtropes|PsmithPsyndrome|hear the orthography}} of spoken text, comments on the odd shape with an appropriate pun. <br />
<br />
Megan's response, "Weird circumflex but okay" is a play on the recent expression [https://www.urbandictionary.com/define.php?term=Weird%20flex%20but%20ok Weird flex, but ok]. A "flex" is bragging about something. A "weird flex" is used when the speaker acknowledges (perhaps ironically) that the first person is attempting to brag about something, but doesn't recognise the thing as brag-worthy. <br />
<br />
Her answer could also be applied to the shape of the crêpe, as circumflex means "bent around".<br />
<br />
In some dialects of English (e.g. British English), and in the original French pronunciation, "crêpe" is said so that the ê is pronounced as in "get" (i.e. "cr-eh-p"), but American English speakers pronounce it like an "A" (i.e. "cr-ay-p").<br />
<br />
The title text continues the wordplay by saying that "A medicine that makes you put two dots over your letters more often is a diäretic".<br />
<br />
The word diäretic is a pun on {{w|diuretic}} (a substance promoting increased urine production), {{w|Diaeresis (diacritic)|diaeresis}} (a symbol in the form of two dots placed above a vowel, as the ä in the made up word diäretic; the adjective form of diaeresis can be spelled "[https://www.thefreedictionary.com/Diaresis dieretic]") and {{w|diacritic}} (a glyph added to a letter to distinguish its sound from the normal version, what both the circumflex and the diaeresis are). See also the comic [[1647: Diacritics]] about the use of these. Taking a diäretic medicine would supposedly cause you to use diaeresis (also known as umlaut) över möre lëtters thän wöuld üsuallÿ bë thë cäse.<br />
<br />
Diacritics are rarely used in English, potentially because of the diverse set of origin languages it developed from, or the wide variation of pronunciations within a same nation, but are a common feature of other languages. In English, they are normally only seen in specific loanwords (such as crêpe) or used for emphasis or decoration (for example the {{w|metal umlaut}} seen in rock bands like {{w|Motörhead}}, {{w|Mötley Crüe}}, {{w|Queensrÿche}}, or {{w|Spın̈al Tap}}). The exception to this is the diaresis, which when it is used at all, is placed over the second vowel in a double-vowel word to indicate a morphological break between them as opposed to a diphthong (e.g. naïve or coöperation). The diaresis is optional, and, especially with words beginning with the co- prefix (e.g. cooperation, coevolution, or coincidence), rarely used. The New Yorker magazine is a famous outlier, advising consistent use of the diaresis in [https://www.newyorker.com/culture/culture-desk/the-curse-of-the-diaeresis its style guide].<br />
<br />
==Transcript==<br />
:[Cueball is holding a plate up in both hand, showing Megan the crepe lying on the plate. His word for crêpe has a different diacritic over the "e" than the normal circumflex (^). Instead it looks more like an open arrow head.]<br />
:Cueball: Check out this crêpe I made!<br />
:Megan: Weird circumflex, but okay.<br />
<br />
{{comic discussion}}<br />
<br />
[[Category:Comics featuring Cueball]]<br />
[[Category:Comics featuring Megan]]<br />
[[Category:Language]]<br />
[[Category:Puns]]<br />
[[Category:Food]]</div>162.158.203.10https://www.explainxkcd.com/wiki/index.php?title=977:_Map_Projections&diff=226643977: Map Projections2022-02-06T10:56:38Z<p>162.158.203.10: /* Winkel-Tripel */</p>
<hr />
<div>{{comic<br />
| number = 977<br />
| date = November 14, 2011<br />
| title = Map Projections<br />
| before = [[#Explanation|↓ Skip to explanation ↓]]<br />
| image = map_projections.png<br />
| titletext = What's that? You think I don't like the Peters map because I'm uncomfortable with having my cultural assumptions challenged? Are you sure you're not... ::puts on sunglasses:: ...projecting?<br />
}}<br />
{{TOC}}<br />
==Explanation==<br />
{{w|Map projection}}, or how to represent the spherical Earth surface onto a flat support (paper, screen...) to have a usable map, is a long-time issue with very practical aspects (navigation, geographical shapes and masses visualization, etc.) as well as very scientific/mathematical ones, involving geometry or even abstract algebra among other things. There is no universal solution to this problem: Any 2D map projection will always distort in a way the spherical reality. Many projections have been proposed in various contexts, each intending to minimize distortions for specific uses (for nautical navigation, for aerial navigation, for landmass size comparisons, etc.) but having drawbacks from other points of view. Some of them are more frequently used than others in mass media and therefore more well-known than others, some are purely historical and now deprecated, some are very obscure, etc.<br />
<br />
[[Randall]] suggests here the idea that someone's "favorite" map projection can reveal aspects of their personality, then goes through a series of them to show what they can mean. <br />
<br />
He may actually believe that all map projections are in a way bad. This could be inferred from the fact that he much later began publishing a series of [[:Category:Bad Map Projections|Bad Map Projections]].<br />
===Mercator===<br />
[[File:MercatorProjection.jpg|frame|The Mercator projection]]<br />
The {{w|Mercator projection}} was introduced by Flemish cartographer Gerardus Mercator in 1569. The main purpose of this map is to preserve compass bearings; for example 13 degrees east of north will be 13 degrees clockwise from the ray pointing toward the top of the map, at every point. A mathematical consequence is the mapping is conformal, i.e. if two roads meet at a certain angle on the surface of the Earth, they will meet at that same angle on the map. It also follows that at every point the vertical and horizontal scales are the same, so locally i.e. considering only a small part of the map, geographical features (shapes, angles) are well represented, which helps a lot in recognizing them on-the-field, or for local navigation in that small part only. For this reason, that projection (or a close variant) is used in several online mapping services (such as Google Maps), which means that it is frequently encountered by the general public. A straight line on the map corresponds to a course of constant bearing (direction), which was very useful for nautical navigation in the past (and thus made that projection very well-known).<br />
<br />
However, from a global point of view, this projection is radically incorrect in how it shows the size of landmasses (for instance, Antarctica and Greenland seem gigantic), and furthermore, it always excludes a small region around each pole (otherwise the map would be of infinite height), so it doesn't provide a complete solution for the problem of map projection. The comic implies that people who like that projection aren't very interested with map issues, and typically use what they are offered without thinking much about it.<br />
<br />
{{clear}}<br />
<br />
===Van der Grinten===<br />
[[File:VanDerGrintenProjection.jpg|frame|The Van der Grinten projection]]<br />
The {{w|Van der Grinten projection}} is not much better than the Mercator. It was adopted by {{w|National Geographic}} in 1922 and was used until they updated to the Robinson projection in 1988.<br />
<br />
The Van der Grinten projection is circular as opposed to the Mercator projection. The fictional person believes a circular map is more fitting to the real Earth's three-dimensional spherical nature because both are round. This belief fails to recognize that a two-dimensional circle has very little in common with the surface of a sphere, and thus this projection still causes a vast distortion of space and area. Because of this, Randall implies the Van der Grinten enthusiast to be optimistic and childishly simple-minded (e.g. "you like circles").<br />
<br />
{{clear}}<br />
<br />
===Robinson===<br />
[[File:RobinsonProjection.jpg|frame|The Robinson projection]]<br />
The {{w|Robinson projection}} was developed by {{w|Arthur H. Robinson}} as a map that was supposed to look nice and is often used for classroom maps. National Geographic switched to this projection in 1988, and used it for ten years, switching to the {{w|Winkel tripel projection|Winkel-Tripel}} in 1998.<br />
<br />
{{w|The Beatles}} was a rock band that enjoyed great commercial success in the 1960s, and are widely considered the best act ever in the genre of popular music. The Beatles, coffee, and running shoes are all things that are very commonly enjoyed and largely uncontroversial, as well as being comforting. Liking these specific things suggests an ordinary, easygoing lifestyle paralleled by the projection.<br />
<br />
{{clear}}<br />
<br />
===Dymaxion===<br />
[[File:DymaxionProjection.jpg|frame|The Dymaxion projection]]<br />
Also called the Fuller Map, the {{w|Dymaxion map}} takes a sphere and projects it onto an icosahedron, that is a polyhedron with 20 triangular faces. It is far easier to unwrap an icosahedron than it is to unwrap a sphere into a 2D object and has very little skewing of the poles. {{w|Buckminster Fuller}} was an eccentric futurist who believed, for example, that world maps should allow no conception of "up" or "down". He was therefore more than happy to defy people's expectations about maps in the pursuit of mathematical accuracy.<br />
<br />
Randall associates the projection to geek subculture and niche markets:<br />
*{{w|Isaac Asimov}} was an American science-fiction writer, who (as well as publishing many textbooks) is considered the father of the modern concept of robots. He invented the {{w|Three Laws of Robotics}}. He also worked on more than 500 books throughout his career.<br />
*{{w|XML}} is the eXtensible Markup Language. It is used to represent data in a format that machines can read and understand, as well as being human-readable. In practice, XML is cumbersome to read.<br />
*{{w|Vibram FiveFingers|Toed shoes}} are a [[1065: Shoes|favorite]] of Randall's to pick on. In society they are seen as a {{w|geek}} clothing item.<br />
*Brought to the world by {{w|Dean Kamen}}, the {{w|Segway PT}} was supposed to be a device that changed the way cities were built. In reality, most jurisdictions have put in place rules specifically against Segways, making them a frustration to own and use within the law (in some states in Australia, it is illegal to use them on public footpaths or roads). Also, the former owner of {{w|Segway Inc.}}, the late {{w|Jimi Heselden}}, accidentally rode his Segway off a cliff in 2010. Ninebot, then owner of the Segway brand, announced in 2020 that the flagship 2-wheeled self-balancing vehicle would be discontinued.<br />
*At the time of comic release, 3D goggles, nowadays widely known as {{w|Virtual reality headset|VR headsets}}, were considered a gimmick at best. The original idea is as old as 3D graphics, but it never really took off until mid-2010s. Earlier products were very unwieldy and offered poor graphics quality, so no one took this technology seriously.<br />
*{{w|Dvorak Simplified Keyboard|Dvorak}} is an alternate keyboard layout to {{w|QWERTY}}. According to legend, QWERTY was invented to help keep manual typewriters from jamming (by placing the most used keys far from each other) but Dr. {{w|August Dvorak}} performed many studies and found the mathematically optimal keyboard layout to reduce finger travel for right handed typists. While some claim Dvorak is technically better than QWERTY, QWERTY had become the standard. Most keyboards were laid out in QWERTY format, but a lot of software exists to remap the keys to DVORAK for those interested in typing faster. Retraining the brain to use Dvorak takes perhaps a week. It has become a [[:Category:Dvorak|recurrent theme]] on xkcd.<br />
<br />
<br />
{{clear}}<br />
<br />
===Winkel-Tripel===<br />
[[File:Winkel-TripelProjection.jpg|frame|The Winkel Tripel projection]]<br />
Proposed by Oswald Winkel in 1921, the {{w|Winkel tripel projection}} tried to reduce a set of three (German: Tripel) main problems with map projections: area, direction, and distance. The {{w|Kavrayskiy VII projection|Kavrayskiy projection}} is very similar to the Winkel Tripel and was used by the USSR, but very few in the Western world know of it.<br />
<br />
The comic links this projection to {{w|hipster}} subculture. The hipster stereotype is to avoid conforming to mainstream fashions. "Post-" refers to a variety of musical genres such as {{w|post-punk}}, {{w|post-grunge}}, {{w|post-minimalism}}, etc. that branch off of other genres.<br />
<br />
;Trivia<br />
*In German "Winkel-Tripel-Projektion" means Winkel's triple projection, and therefore the hyphen shouldn't be there: "Winkel Tripel" or "Winkel tripel".<br />
*This projection was later used in [[2242: Ground vs Air]].<br />
*Winkel is also the German word for "angle".<br />
{{clear}}<br />
<br />
===Goode Homolosine===<br />
[[File:GoodeHomolosineProjection.jpg|frame|The Goode Homolosine projection]]<br />
The {{w|Goode homolosine projection}} takes a different approach to skewing a sphere into a roughly circular surface. An orange peel can be taken from an orange and flattened with fair success; this is roughly the procedure that {{w|John Paule Goode}} followed in creating this projection. Randall is suggesting that people who like this map also prefer relatively easy solutions to other things in life, despite those solutions having nuanced problems that are more difficult to address.<br />
<br />
People often make arguments that if normal people ran the United States, then the US wouldn't be in the trouble it is. This is from the belief that career politicians are simply out to make money and will only act in the interest of their constituency when their continued easy life is threatened (usually around election time). While some form of this view is very common and probably pretty much correct, Randall is saying that someone who likes this map may take this to extremes.<br />
<br />
Airline food is another, much maligned, problem. How do you store enough food to feed people on long airplane trips? What kind of food can be served in an enclosed, low-air-pressure environment? The common solution is to use some kind of prepackaged, reheated meal. Randall is saying that the people in favor of the Goode Homolosine wonder why the airlines don't simply order meals from the restaurants in the airport, store that food, and serve it, rather than using bland reheated food. However, this seemingly-obvious solution ignores how being in an airplane dulls your sense of taste. Airplane food is actually over seasoned for eating on the ground, meaning that if airlines switched to restaurant food it would probably taste even blander.<br />
<br />
Older cars burned oil like mad fiends, and oil back then would become corrosive to the innards of an engine, so oil had to be changed often. But, with the introduction of synthetic motor oil and better designed engines, new cars only need their oil changed about every 10,000 to 15,000 miles. A common conspiracy theory is that modern automobile oil manufacturers still recommend that car owners change their oil every 3,000-5,000 miles to "drum" up more business, even though that frequency is unnecessary.<br />
<br />
All of these references suggest that people who like the Goode Homolosine projection are fans of easy solutions to problems. However, the solutions would not necessarily work in practice. For instance: the restaurants might have trouble making enough food for the whole plane, and it could get cold before being served; the air conditions [http://www.nbcnews.com/health/one-reason-airline-food-so-bad-your-own-tastebuds-6C10823522 aboard planes] can affect taste, so airlines say they optimize for this; there is no such thing as a "normal" person, and if there were, he/she would have virtually no chance at actually getting into government office; and the Goode Homolosine projection, while mostly resembling a flattened orange peel as suggested by the earlier analogy, does indeed cut down on distortion, but also has serious problems of its own, such as leaving huge gaps of nothingness between the continents, making distances across the oceans difficult to visualize.<br />
<br />
{{clear}}<br />
<br />
===Hobo–Dyer===<br />
[[File:Hobo-DyerProjection.jpg|frame|The Hobo–Dyer projection]]<br />
The {{w|Hobo–Dyer projection}} was commissioned by Bob Abramms and Howard Bronstein and was drafted by Mick Dyer in 2002. It is a modified {{w|Behrmann projection}}. The goal was to be a more visually pleasing version of the Gall–Peters.<br />
<br />
As is discussed in the Gall–Peters explanation, the Gall–Peters was developed to be equal area, so that economically disadvantaged areas can at least take comfort in the fact that their country is represented correctly by area on maps.<br />
<br />
Randall associates the Hobo–Dyer projection to "crunchy granola" — a stereotype associated with vegetarianism, environmental activism, anti-war activism, liberal political leanings, and some traces of {{w|hippie}} culture.<br />
<br />
With feminism becoming mainstream and alternative genders being more widely accepted, some have begun to invent gender-neutral pronouns so that when referring to a person whose gender is not known they cannot be offended by being referred to by the wrong pronouns. In {{w|Middle English}} 'they' and 'their' were {{w|Singular they|accepted genderless pronouns that could replace 'he', 'she'}} as well as be used to represent a crowd, but this usage is considered by some to be grammatically incorrect because of the plural/singular debate ([https://www.merriam-webster.com/video/the-awkward-case-of-his-or-her stupid Victorian Grammarians!]). There have been {{w|gender-neutral pronoun#Invented pronouns|many attempts at popularizing invented gender-neutral pronouns}} and they are beginning to achieve some degree of success in the mainstream.<br />
<br />
{{clear}}<br />
<br />
===Plate Carrée===<br />
[[File:PlateCarreeProjection.jpg|frame|The Plate Carrée projection]]<br />
Also known as the {{w|Equirectangular projection}}, it has been in use since, apparently, 100 AD. The benefit of this projection is that latitude and longitude can be used as x,y coordinates. This makes it especially easy for computers to graph data on top of it.<br />
<br />
According to the comic, the projection appeals to people who find much beauty in simplicity.<br />
<br />
{{clear}}<br />
<br />
===A Globe!===<br />
[[File:GlobeProjection.jpg|frame|The Globe "projection"]]<br />
In any good discussion there has to be at least one smart-ass. This is a comic about map projections, that is, the science of taking a sphere and flattening it into 2 dimensions. The smart-ass believes that we shouldn't even try: a sphere is, tautologically, the perfect representation of a sphere.<br />
<br />
To quote ''{{w|The Princess Bride}}'': "Yes, you're very smart. Shut up."<br />
<br />
A globe is, of course, the "map projection" used by {{w|Google Earth}} when zoomed out.<br />
<br />
{{clear}}<br />
<br />
===Waterman butterfly===<br />
[[File:WatermanButterflyProjection.jpg|frame|The Waterman Butterfly projection]]<br />
Similar to the Dymaxion, the {{w|Waterman butterfly projection}} turns a sphere into an octahedron, and then unfolds the net of the octahedron, which was devised by mathematician {{w|Waterman polyhedron|Steve Waterman}} based upon the work of {{w|Bernard J.S. Cahill}}.<br />
<br />
Bernard Cahill published a [http://www.genekeyes.com/B.J.S._CAHILL_RESOURCE.html butterfly map] in 1909. Steve Waterman probably has the only extant "ready to go" map following the same general principles, though Gene Keys may not be far behind. Waterman has a poem with graphics in a similar vein to this xkcd comic that is worth reading.[http://web.archive.org/web/20120118095915/http://watermanpolyhedron.com/worldmap.html]<br />
<br />
[https://www.degruyter.com/downloadpdf/j/pcr.2016.48.issue-4/pcr-2016-0014/pcr-2016-0014.pdf Polyhedral projections] like Cahill, Dymaxion or Waterman typically offer better accuracy of size, shape and area than flat projections, at the expense of compass directionality, connectedness, and other complications.<br />
<br />
The joke is that the person responding deeply understands map projections; anyone who knows of this projection is a person that Randall would like to get to know.<br />
<br />
{{clear}}<br />
<br />
===Peirce quincuncial===<br />
[[File:PeirceQuincuncialProjection.jpg|frame|The Peirce Quincuncial projection]]<br />
The {{w|Peirce quincuncial projection}} was devised by {{w|Charles Sanders Peirce}} in 1879 and uses {{w|complex analysis}} to make a {{w|conformal mapping}} of the Earth, that conforms except for four points which would make up the midpoints of sides and lie on equator (the equator is represented by a square and the corners connect the sides in the middle.)<br />
<br />
{{w|Inception}} was a 2010 movie about {{w|meta}} {{w|lucid dream}}ing. It has a complex story that is difficult to follow and leaves the viewer with many questions at the end, and almost needs to be watched multiple times to be understood.<br />
<br />
The human brain is not well developed to deal with oddly obvious things. One example is that everyone has a skeleton, but everyone is surprised to see a part of their body represented by an X-ray. Another is the fascinating complexity of the human hand, a machine which is amazingly complex, driven by a complex interplay of electrical and chemical signals; yet is the size of the hand and so useful. A fascination with or fixation on {{tvtropes|ContemplatingYourHands|such thoughts}} is often associated with an altered state of mind brought on by marijuana consumption. Therefore, Randall may be implying that this map would appeal to stoners.<br />
<br />
{{clear}}<br />
<br />
===Gall–Peters===<br />
[[File:Gall-PetersProjection.jpg|frame|The Gall–Peters projection]]<br />
The {{w|Gall–Peters projection}} is mired in controversy, surprisingly for a map. {{w|James Gall}}, a 19th-century clergyman, presented this projection in 1855 before the {{w|British Association for the Advancement of Science}}. In 1967, the filmmaker {{w|Arno Peters}} created the same projection and presented it to the world as a "new invention" that put poorer, less powerful countries into their rightful proportions (as opposed to the Mercator). Peters played the marketing game and got quite a few followers of his map by saying it had "absolute angle conformality," "no extreme distortions of form," and was "totally distance-factual" in an age when society was very concerned about social justice. All of these claims were in fact false. The Mercator projection distorts size in favor of shape, and Gall-Peters distorts shape in favor of size, being especially inaccurate at the equator and the poles.<br />
<br />
The implication is that the fans of this map are pompously concerned with social justice, and willing either to lie or convey marketing mistruths to promote that cause. Alternatively Randall just dislikes this map projection so much due to the above mentioned inaccuracies, that he hates anyone who likes it.<br />
<br />
{{clear}}<br />
<br />
===Title text===<br />
The title text makes a joke that goes to the familiar meme from ''{{w|CSI: Miami}}'', in which the star, David Caruso starts a sentence, then puts on his sunglasses and ends the sentence with a corny pun. In this case, the pun is on {{w|map projection}} and {{w|projection (psychology)|projection}} in psychology. Psychological projection is an unconscious defense mechanism wherein a person who is uncomfortable with their own impulses denies having them and attributes them to other people, and blames these people for these impulses. The Sunglasses internet meme has been used [[:Category:Puts on sunglasses|in other comics]] as well.<br />
<br />
==Transcript==<br />
:What your favorite<br />
:'''Map Projection'''<br />
:says about you<br />
:[All of these are organized as Title, a copy of the particular projection underneath, and what it says about you under that.]<br />
<br />
:*Mercator<br />
:**You're not really into maps.<br />
:*Van der Grinten<br />
:**You're not a complicated person. You love the Mercator projection; you just wish it weren't square. The Earth's not a square, it's a circle. You like circles. Today is gonna be a good day!<br />
:*Robinson<br />
:**You have a comfortable pair of running shoes that you wear everywhere. You like coffee and enjoy The Beatles. You think the Robinson is the best-looking projection, hands down.<br />
:*Dymaxion<br />
:**You like Isaac Asimov, XML, and shoes with toes. You think the Segway got a bad rap. You own 3D goggles, which you use to view rotating models of better 3D goggles. You type in Dvorak.<br />
:*Winkel-Tripel<br />
:**National Geographic adopted the Winkel-Tripel in 1998, but you've been a W-T fan since ''long'' before "Nat Geo" showed up. You're worried it's getting played out, and are thinking of switching to the Kavrayskiy. You once left a party in disgust when a guest showed up wearing shoes with toes. Your favorite musical genre is "Post–".<br />
:*Goode Homolosine<br />
:**They say mapping the Earth on a 2D surface is like flattening an orange peel, which seems enough to you. You like easy solutions.You think we wouldn't have so many problems if we'd just elect ''normal'' people to Congress instead of Politicians. You think airlines should just buy food from the restaurants near the gates and serve ''that'' on board. You change your car's oil, but secretly wonder if you really ''need'' to.<br />
:*Hobo-Dyer<br />
:**You want to avoid cultural imperialism, but you've heard bad things about Gall-Peters. You're conflict-averse and buy organic. You use a recently-invented set of gender-neutral pronouns and think that what the world needs is a revolution in consciousness.<br />
:*Plate Carrée <small>(Equirectangular)</small><br />
:**You think this one is fine. You like how X and Y map to latitude and longitude. The other projections overcomplicate things. You want me to stop asking about maps so you can enjoy dinner.<br />
:*A Globe!<br />
:**Yes, you're very clever.<br />
:*Waterman Butterfly<br />
:**Really? You know the Waterman? Have you seen the 1909 Cahill Map it's based— ...You have a framed reproduction at home?! Whoa. ...Listen, forget these questions. Are you doing anything tonight?<br />
:*Peirce Quincuncial<br />
:**You think that when we look at a map, what we really see is ourselves. After you first saw ''Inception'', you sat silent in the theater for six hours. It freaks you out to realize that everyone around you has a skeleton inside them. You ''have'' really looked at your hands.<br />
:*Gall-Peters<br />
:**I ''hate'' you.<br />
<br />
{{comic discussion}}<br />
<br />
[[Category:Maps]]<br />
[[Category:Dvorak]]<br />
[[Category:Puts on sunglasses]]<br />
[[Category:Puns]]</div>162.158.203.10https://www.explainxkcd.com/wiki/index.php?title=Talk:2572:_Alien_Observers&diff=226138Talk:2572: Alien Observers2022-01-31T16:12:03Z<p>162.158.203.10: reconstructed original quoting structure</p>
<hr />
<div><!--Please sign your posts with ~~~~ and don't delete this text. New comments should be added at the bottom.--><br />
<br />
This is my first explanation, i know it is really bad but i wanted to give it a go[[User:ElijahRock|ElijahRock]] ([[User talk:ElijahRock|talk]]) 20:39, 24 January 2022 (UTC)<br />
:Great you are helping. Often easier to continue and improve existing explanations rather than start as you did from scratch. Even if most of the original version end up getting changed. I make alot of edits but rarely begin the explanation. --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 22:01, 24 January 2022 (UTC)<br />
::thanks! glad i could be helpful [[User:ElijahRock|ElijahRock]] ([[User talk:ElijahRock|talk]]) 16:02, 25 January 2022 (UTC)<br />
<br />
I don't think it makes sense to track each human individually, I was under the impression that it was a "before and after" picture. - [[Special:Contributions/172.70.130.153|172.70.130.153]] 22:14, 24 January 2022 (UTC)<br />
:I think they ''both'' track humans individually, and that this is a (representative) before-and-after picture. They probably have minions/computers/whatever continuously updating the actual flight-boundaries as people move around (and go into camera/phone/cameraphone stores and come out with something new) but this is a 'management briefing' that extraordinarily reports this otherwise mundane development as an individual matter, with a visual aid to make the report sink in. Just going to show how aliens can be both so alien and yet amazingly human in their bureaucratic minutiae. [[Special:Contributions/172.70.85.73|172.70.85.73]] 01:21, 25 January 2022 (UTC) <br />
::What I was trying to say is that they don't actually keep track of which phone any random person has (or alter their flight path respectively), it's just a matter of "this is the furthest human technology can go". - [[Special:Contributions/172.70.131.122|172.70.131.122]] 00:28, 26 January 2022 (UTC)<br />
:::I think they ''do'' track everyone's individual capabilities. (They're that good at observation!) That's why they're so specific about what two individuals have done to upgrade their media capabilities. On the other hand, I think the on-screen image is just a representative diagram, rather than real-time/real-geography with real UFO positions - but it depicts the effective alterations of approach distances that this person's now 'toy' has enforced upon these Little Green Voyeurs. [[Special:Contributions/172.70.162.155|172.70.162.155]] 00:46, 26 January 2022 (UTC)<br />
<br />
Feels like this is a partial rebuttal of https://www.explainxkcd.com/wiki/index.php/1235:_Settled [[User:Boatster|Boatster]] ([[User talk:Boatster|talk]]) 23:08, 24 January 2022 (UTC)<br />
:Didn't see your comment, before, but added this link myself in my own way. [[Special:Contributions/172.70.85.73|172.70.85.73]] 01:21, 25 January 2022 (UTC)<br />
:: cheers [[User:Boatster|Boatster]] ([[User talk:Boatster|talk]]) 14:21, 26 January 2022 (UTC)<br />
<br />
I think that Randall is also referring to the fact that all footage of "UFOs" show them flying erratically. This being due to the fact that this is the way refraction works. Sorry for the bad English, not sure how to explain it :) EDIT: It could also refer to the fact that a lot of people still believe in UFOs even though this is a well-known phenomenon that is known to be the cause of a lot of these sightings. As I said below though most of these kind of sightings are reported by pilots flying at high altitudes, so now I'm not sure...[[User:The Cat Lady|-- The Cat Lady]] ([[User talk:The Cat Lady|talk]]) 23:18, 24 January 2022 (UTC)<br />
:(Ditto above, didn't see this before starting editing, but...) I put it down to zoom-wobble in what I just inserted. Though didn't say that this is just normal (acceptable) hand-wobble augmented by the zoom needed to frame the distant whateveritis. Yes, rapidly changing refraction through moving air is probably also a thing (usually heat haze during the day, or the subtler stuff that astronomical telescopes have to deal with at night with lasers and adaptive optics and/or electronic post-processing) but I'm happy to leave it at zoom-wobble without going back and adding your suggestion. Do edit it if you feel like it, though, that being how this site works. [[Special:Contributions/172.70.85.73|172.70.85.73]] 01:21, 25 January 2022 (UTC)<br />
<br />
:: The zoom-wobble is a great explanation! I didn't think of that at all :P However, there's lots of footage that exists from non-zoomed, fixed cameras like security cameras and 8 mm film cameras on tripods, which sort of obviates that explanation. But also, I did a quick search for footage like that and it looks nothing like refraction phenoma (at least the examples I could find) so my explanation isn't quite correct either. I think those kind of sightings are mostly reported by pilots at high altitudes, as those are more likely conditions for this to happen. I'm still leaning more towards my explanation than yours for now though:) I'm going to leave this here for now and wait for more discussion before I change anything [[User:The Cat Lady|-- The Cat Lady]] ([[User talk:The Cat Lady|talk]]) 08:53, 25 January 2022 (UTC)<br />
<br />
Zoom is a misnomer for the lens setups modern phones come with. As an example, the Xiaomi Mi 11 Ultra does not have any zoom - it has three distinct cameras, each with their own prime lens. You can switch between the cameras, but this is not zooming. [[User:Paul-Simon|Paul-Simon]] ([[User talk:Paul-Simon|talk]]) 13:13, 25 January 2022 (UTC)<br />
<br />
I have added that "Human 38XT11" is a reference to THX 1138... anyone who can spot something similar with Human 910-25J-1Q38 or B-C54? --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 13:42, 25 January 2022 (UTC)<br />
:1Q38 can be seen as the 1st quarter of 2038, also known as {{w|Epochalypse}}.[[Special:Contributions/162.158.202.177|162.158.202.177]] 11:32, 26 January 2022 (UTC)<br />
:[https://en.wikipedia.org/wiki/1Q84 1Q84] is the title of a novel by Haruki Murakami. The meaning of the title is the year 1984, since 9 in Japanese is ''kyū''. So perhaps 1Q38 is code for 1938? [[User:Entropy|Entropy]] ([[User talk:Entropy|talk]]) 14:05, 25 January 2022 (UTC)<br />
:Can't they just be random numbers that Randall decided to use? Why does everything need to be a reference to something? [[Special:Contributions/172.70.206.205|172.70.206.205]] 18:43, 25 January 2022 (UTC)<br />
::people like to see patterns even if there are none[[User:New editor|New editor]] ([[User talk:New editor|talk]]) 21:27, 25 January 2022 (UTC)<br />
::If Randall had chosen them randomly, they'd both [[221:_Random_Number|have ended up]] as "4444-4444-4444-4444"... ;) [[Special:Contributions/162.158.159.125|162.158.159.125]] 20:44, 25 January 2022 (UTC)<br />
::I agree that some of the numbers may have been chosen randomly. But with Randall, being fan of Starwars, and often putting in funny references, I cannot imagine he would manage to put in the letters from THX1138 numbers in the first part of the first humans code, by a random coincidence, it is just too unlikely. But that doesn't mean the other numbers need to reference anything. --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 17:41, 27 January 2022 (UTC)<br />
<br />
I don't get why starting a YouTube-channel should have any impact on flying patterns because it's the filming and not the publishing that is the problem. The videos shown on that particular channel can be years old so the erratic flight behavior should take place as soon as a human has the capability to '''shoot''' a video rather than '''publish''' it. [[User:Kimmerin|Kimmerin]] ([[User talk:Kimmerin|talk]]) 08:25, 26 January 2022 (UTC)<br />
:Maybe the aliens is [[:Category:Alien Visitors|not that bright]], just good at technology, I still don't get the lines spoken by the other alien and the reply to that. It makes no sense to me. As with the title text. Agree that it makes no difference to have a channel. --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 17:42, 27 January 2022 (UTC)<br />
<br />
These aliens need to do a better job of tracking human technology. One camera, the [https://www.dpreview.com/products/nikon/compacts/nikon_cpp900 Nikon P900] has an optical zoom ratio of 83x and a digital zoom of 166x. They should have made flight compensations immediately upon its product announcement back in 2015. Or at least upon its consumer rollout in 2017, not after the fact. [[User:These Are Not The Comments You Are Looking For|These Are Not The Comments You Are Looking For]] ([[User talk:These Are Not The Comments You Are Looking For|talk]]) 04:29, 30 January 2022 (UTC)</div>162.158.203.10https://www.explainxkcd.com/wiki/index.php?title=2568:_Spinthariscope&diff=2245342568: Spinthariscope2022-01-16T10:17:15Z<p>162.158.203.10: /* Explanation */ wp link</p>
<hr />
<div>{{comic<br />
| number = 2568<br />
| date = January 14, 2022<br />
| title = Spinthariscope<br />
| image = spinthariscope.png<br />
| titletext = Other high scorers are melt-in-your-hand aluminum-destroying gallium and tritium-powered glowsticks. Lawn darts are toward the other end.<br />
}}<br />
*This was the third comic to come out after the [[Countdown in header text]] started. <br />
<br />
==Explanation==<br />
{{incomplete|Created by a SPINTHARISCOPE - Please change this comment when editing this page. Do NOT delete this tag too soon.}}<br />
This is another comic with one of [[Randall|Randall's]] [[:Category:Fun fact|fun facts]].<br />
<br />
As stated in the comic, a {{w|spinthariscope}} is a device with a small amount of radioactive material ({{w|americium}} or <br />
{{w|thorium}}) and a screen. When one of the radioactive atoms decays, it emits an {{w|alpha particle}}, which strikes the screen, which emits a small flash of light. You can see these flashes by looking through a lens.<br />
<br />
It was invented in 1903 initially as a scientific instrument, but was soon replaced by more accurate and quantitative devices. But the original device was still popular for some time as an educational toy for children, and you can still get them today.<br />
<br />
The joke in the comic is that most people have little understanding of radiation, and overreact to any mention that something is radioactive. So when Cueball tells Megan, White Hat, and Ponytail that the toy contains radioactive material, they're shocked and scared. But the amount of radioactive material in the toy is very tiny and the radiation is itself so trivially contained that there's practically no risk from it. The short-ranged {{w|alpha particles}} are likely stopped by the lens through which the harmless flashes of light (from particles that instead hit and neutralise in the internal screen element) are seen. Alpha decay always leads to an unstable decay product, which results in further decay (always gamma decay, and sometimes beta decay as well) which are less easily blocked; but the amount of such radiation from these decay products is negligible.<br />
<br />
The fun fact in the caption says that Spinthariscopes have the highest ratio of "that can't possibly be safe and legal" to actual safety and legality of any known toy. Because, when people hear about Spinthariscopes for the first time, they instantly assume, due to the radioactive material inside, that they must be very dangerous. They thus also question if such a toy is at all legal to make or own in the first place. But the fact is that Spinthariscopes are both safe and are legal to make, sell and own. So, the perceived danger and presumption that it must be illegal is at a very high number, and the actual danger and the actual legality results in a very low number on the same scale. It is this ratio between those two numbers that are the highest for Spinthariscopes, higher than for any other known toys.<br />
<br />
The formulation, however, is confusion, because the actual safety and legality of Spinthariscopes are high. And if looked at like this, then it is two large numbers that should be divided. This is obviously not the case as can be seen from the other toys mentioned in the title text.<br />
<br />
The title text mentions some other materials/toys that sound dangerous but aren't. {{w|Gallium}} is a metallic element with a low melting point of 29.76°C (85.568°F) so it will melt in your hand. Additionally, gallium has strange properties when it interacts with aluminum, causing it to [https://www.youtube.com/watch?v=IgXNwLoS-Hw "melt"] or become brittle. {{w|Tritium}} is a radioactive isotope of hydrogen, but {{w|Tritium radioluminescence|can be used}} to create {{w|glowstick}}s and other lighted objects. Though these two toys might seem dangerous, they are actually typically used perfectly safely.<br />
<br />
At the opposite end of the spectrum is {{w|lawn darts}}, a toy containing large darts that are thrown into the air to fall back down onto a target that's placed or marked upon the ground quite near the players' positions. Contrary to the spinthariscope, which sounds dangerous but is actually harmless, lawn darts sound relatively innocent but can cause severe injury if you accidentally hit a person (and a few children were even {{w|Lawn darts|killed}}), so they were {{w|Lawn_darts#Safety_and_bans_in_the_U.S._and_Canada|banned in the US and Canada}} in the 1980s. When sharpened, these toys even [https://www.youtube.com/watch?v=1EFAVGIylqE compare] quite favorably to {{w|plumbata|weapons of war}}.<br />
<br />
Today many houses have {{w|Smoke_detector|smoke detectors}} using {{w|Smoke_detector#Ionization|ionization}} caused by radioactive decay of {{w|Americium-241}} to detect the smoke. So having something with radioactive material in your house is quite common, and in this case increases the safety level for those houses.<br />
<br />
==Transcript==<br />
:[Cueball is holding a small item up in on hand in front of his three friends. Megan has her arms lifted and bent in front of her, White Hat has his arms raised over his head and Ponytail is pointing at Cueball while her other hand, held down behind her, is balled into a fist.]<br />
:Cueball: It's a spinthariscope, a 1940s toy with a radioactive isotope inside. If you let your eyes adjust to total darkness and look into the lens, you can see the flashes of individual atoms decaying.<br />
:Megan: What??<br />
:White Hat: ''Aaaaa!''<br />
:Ponytail: Get it away!<br />
<br />
:[Caption below the panel:]<br />
:Fun fact: Spinthariscopes have the highest ratio of "that can't possibly be safe and legal" to actual safety and legality of any known toy.<br />
<br />
{{comic discussion}}<br />
<br />
[[Category:Fun fact]]<br />
[[Category:Comics featuring Cueball]]<br />
[[Category:Comics featuring Megan]]<br />
[[Category:Comics featuring White Hat]]<br />
[[Category:Comics featuring Ponytail]]<br />
[[Category:Chemistry]]<br />
[[Category:Physics]]</div>162.158.203.10https://www.explainxkcd.com/wiki/index.php?title=2560:_Confounding_Variables&diff=2231442560: Confounding Variables2021-12-27T18:13:00Z<p>162.158.203.10: /* Explanation */</p>
<hr />
<div>{{comic<br />
| number = 2560<br />
| date = December 27, 2021<br />
| title = Confounding Variables<br />
| image = confounding_variables.png<br />
| titletext = You can find a perfect correlation if you just control for the residual.<br />
}}<br />
<br />
==Explanation==<br />
{{incomplete|Created by a MISLEADING DATASET - Please change this comment when editing this page. Do NOT delete this tag too soon.}}<br />
In statistics, a ''confounding variable'' is a third variable that's related to the independent variable, and also causally related to the dependent variable. An example is that you see a correlation between sunburn rates and ice cream consumption; the confounding variable is temperature: high temperatures cause people go out in the sun and get burned more, and also eat more ice cream.<br />
<br />
One way to control for a confounding variable by restricting your dataset to samples with the same value of the confounding variable. But if you do this too much, your choice of that "same value" can produce results that don't generalize. Common examples of this in medical testing are using subjects of the same sex or race -- the results may only be valid for that sex/race, not for all people.<br />
<br />
There can also often be multiple confounding variables. It may be difficult to control for all of them without narrowing down your dataset so much that it's not useful. So you have to choose which variables to control for, and this choice biases your results.<br />
<br />
In the final panel, Blondie suggests a sweet spot in the middle, where both confounding variables and your control impact the end result, thus making you "doubly wrong". "Doubly wrong" result would simultaineously display wrong correlations (not enough of controlled variables) and be too narrow to be useful (too many controlled variables).<br />
<br />
Finally she admits that no matter what you do the results will be misleading, so statistics are useless.<br />
<br />
In the title text, the ''residual'' refers to the difference between any particular data point and the graph that's supposed to describe the overall relationship. The collection of all residuals is used to determine how well the curve fits the data. If you control for this by selecting only points with the same residual you'll get a perfect correlation, but the results are meaningless because you're ignoring all the data points that don't agree with your hypothesis.<br />
<br />
==Transcript==<br />
{{incomplete transcript|Do NOT delete this tag too soon.}}<br />
If you don't control for confounding variables, they'll mask the real effect and mislead you.<br />
But if you control for too MANY variables, your choices will shape the data and you'll mislead yourself.<br />
Somewhere in the middle is the sweet spot where you do both, making you doubly wrong. <br />
Stats are a farce and truth is unknowable. See you next week!<br />
{{comic discussion}}</div>162.158.203.10https://www.explainxkcd.com/wiki/index.php?title=2547:_Siren&diff=2214512547: Siren2021-11-27T08:54:06Z<p>162.158.203.10: Title text explanation</p>
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<div>{{comic<br />
| number = 2547<br />
| date = November 26, 2021<br />
| title = Siren<br />
| image = siren.png<br />
| titletext = Directions from CITY OF TROY to ITHACA / Total time: 10y 54d 14h 25m / Warning: Route crosses an international border / route includes capture by the goddess Calypso / route includes a ferry<br />
}}<br />
<br />
==Explanation==<br />
{{incomplete|Created by a ODYSSEUS’S BROKEN GPS - Please change this comment when editing this page. Do NOT delete this tag too soon.}}<br />
{{w|Odysseus}} is the hero of the Greek epic ''{{w|Odyssey}}'' by {{w|Homer}}. The poem concerns the journey of Odysseus back home to his homeland from the newly defeated Troy, however he inadvertently angered Poseidon causing the journey to take 10 years. In the poem, {{w|Circe}} warns Odysseus of the {{w|siren (mythology)|sirens}}, who sing beautiful songs that lure sailors to the shore, their boat sinking before they reach it due to jagged rocks surrounding the islands. This comic suggests that Odysseus was being told to ignore a {{w|Satellite navigation device|GPS}}, rather than the Sirens. GPSs did not exist during the time the poem was written {{citation needed}}, so this is not the case.<br />
<br />
The title text shows what the route description could have looked like, had Odysseus indeed used a modern navigation system. It includes the start and destination of the route, the estimated duration and warnings about special circumstances of the journey.<br />
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Normally, the sea voyage from the City of Troy to Ithaca should take much less than ten years. For Odysseus it took so long because of the many obstacles he had to face, so the navigation system would have some sort of clairvoyance function built in.<br />
<br />
"Route crosses an international border" and "Route includes a ferry" are standard warnings included in a route description. The latter alludes to the fact that Odysseus made the voyage by sea. "Route includes capture by the goddess Calypso" is not normally something that a navigation system would warn about.<br />
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==Transcript==<br />
{{incomplete transcript|Do NOT delete this tag too soon.}}<br />
<br />
:[Circe is speaking to Odysseus.]<br />
:Circe: Remember, Odysseus:<br />
:Circe: As you pass the rocks you will hear a woman calling out to you, urging you to stray from your path, but plug your ears and hold your course, for her beguiling lies will draw you to a watery grave.<br />
:Circe: I don't know ''why'' they can't just fix it. I keep filing error reports.<br />
<br />
:[Caption below the panel:]<br />
:Circe was actually just telling Odysseus to ignore his GPS.<br />
<br />
{{comic discussion}}</div>162.158.203.10https://www.explainxkcd.com/wiki/index.php?title=Talk:2536:_Wirecutter&diff=220183Talk:2536: Wirecutter2021-11-02T07:33:19Z<p>162.158.203.10: </p>
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<div><!--Please sign your posts with ~~~~ and don't delete this text. New comments should be added at the bottom.--><br />
Note: they don't say they tried out a large number of ''religions'' but a large number of '''belief systems'''. This could include things like "Libertarianism" or "Monarchists". (By CWALLENPOOLE, but not signed in.)<br />
:But the picture of the article title says “The Best Religion” [[Special:Contributions/108.162.216.233|108.162.216.233]] 20:31, 1 November 2021 (UTC)<br />
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The phrase "highly controversial" should not be used in the explanation. For the record, I am opposed to the things listed in that sentence and my objection is not based in a desire to defend them. Religion itself might be said to be "highly controversial" so the use in the last sentence is both superfluous and biased. [[Special:Contributions/172.70.82.53|172.70.82.53]] 00:34, 2 November 2021 (UTC)<br />
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I really want this article to be real. ----Dave<br />
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The major problem with trying multiple religions is that to fully test a religion you need to die - and most people only die once, with the ability to die multiple times being exclusive feature of small number of religions. -- [[User:Hkmaly|Hkmaly]] ([[User talk:Hkmaly|talk]]) 04:49, 2 November 2021 (UTC)<br />
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It doesn't look like the search bar text says "search," but I can't make out what it actually says.--[[User:KrazyKat|KrazyKat]] ([[User talk:KrazyKat|talk]]) 06:33, 2 November 2021 (UTC)<br />
:Maybe it says Seance, since for "seach" the high stoke from the H is missing. -- [[Special:Contributions/162.158.203.10|162.158.203.10]] 07:33, 2 November 2021 (UTC)</div>162.158.203.10