https://www.explainxkcd.com/wiki/api.php?action=feedcontributions&user=Kylejlin&feedformat=atomexplain xkcd - User contributions [en]2024-03-28T15:12:51ZUser contributionsMediaWiki 1.30.0https://www.explainxkcd.com/wiki/index.php?title=Chrome_Extension&diff=166331Chrome Extension2018-11-25T05:03:52Z<p>Kylejlin: Add licensing details</p>
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<div>The [https://chrome.google.com/webstore/detail/explain-xkcd/fpmkngibepdfagmmmenjbfmgohlddakg Explain xkcd Chrome Extension] is an open source [https://en.wikipedia.org/wiki/Google_Chrome#Extensions Chrome extension] that allows users to navigate from [https://xkcd.com xkcd.com] to the corresponding wiki entry by just clicking a button.<br />
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== Installation ==<br />
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The extension can be installed [https://chrome.google.com/webstore/detail/explain-xkcd/fpmkngibepdfagmmmenjbfmgohlddakg here].<br />
<br />
== Usage ==<br />
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When viewing a comic on xkcd.com, click the [[Black Hat]] icon at the top right (where all the extension icons are located), and the explanation will be opened in a new tab.<br />
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== Contributing ==<br />
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The source can be found [https://github.com/kylejlin/explain-xkcd on GitHub], under the {{w|MIT License}}.</div>Kylejlinhttps://www.explainxkcd.com/wiki/index.php?title=Chrome_Extension&diff=166330Chrome Extension2018-11-25T05:02:15Z<p>Kylejlin: Add a page on the Chrome Extension</p>
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<div>The [https://chrome.google.com/webstore/detail/explain-xkcd/fpmkngibepdfagmmmenjbfmgohlddakg Explain xkcd Chrome Extension] is an open source [https://en.wikipedia.org/wiki/Google_Chrome#Extensions Chrome extension] that allows users to navigate from [https://xkcd.com xkcd.com] to the corresponding wiki entry by just clicking a button.<br />
<br />
== Installation ==<br />
<br />
The extension can be installed [https://chrome.google.com/webstore/detail/explain-xkcd/fpmkngibepdfagmmmenjbfmgohlddakg here].<br />
<br />
== Usage ==<br />
<br />
When viewing a comic on xkcd.com, click the [[Black Hat]] icon at the top right (where all the extension icons are located), and the explanation will be opened in a new tab.<br />
<br />
== Contributing ==<br />
<br />
The source can be found [https://github.com/kylejlin/explain-xkcd on GitHub].</div>Kylejlinhttps://www.explainxkcd.com/wiki/index.php?title=759:_3x9&diff=166223759: 3x92018-11-21T00:52:39Z<p>Kylejlin: Add alternate interpretation</p>
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<div>{{comic<br />
| number = 759<br />
| date = June 28, 2010 <br />
| title = 3x9<br />
| image = 3x9.png<br />
| titletext = Handy exam trick: when you know the answer but not the correct derivation, derive blindly forward from the givens and backward from the answer, and join the chains once the equations start looking similar. Sometimes the graders don't notice the seam.<br />
}}<br />
<br />
==Explanation==<br />
In college courses with a very large number of students (picture the huge, tired, amphitheater-style lecture halls shown in any movie or TV show about college), teaching assistants are often employed to help the professors grade student work. In math and science courses, students are expected to solve the problems and show their work as supporting evidence. Due to the high volume of work to grade, whether it's being done by the professor or a TA, the grader will get lazy and look for correct answers and the existence of work without checking that the work is accurate.<br />
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The math shown in this comic switches from √ being square root notation to it being division notation midway. That is an illegal operation. But the correct answer is reached anyway, because 27 is the correct answer to 3 &times; 9, 3√81, ''and'' 81 &divide; 3.<br />
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More generally, this pattern holds true for any number and its square; namely, 𝑥𝑦 = 𝑦&sup2; &divide; 𝑥 whenever 𝑦 = x&sup2; &nbsp; (... namely, x*y = y^2/x whenever y=x^2) .<br />
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The title text describes another technique usable when you remember the answer but not the calculations. It requires modifying the equation and the answer at the same time, hoping that at one point they'll look similar. Some students picture every step in the calculations, others skip some, as they seem obvious to them. Merging the equations once they look similar may trick the examiner into thinking that the step between them is obvious to the student, even if he IS checking the calculations. The side effect (not mentioned) is that while doing this, you may actually realize what the calculations should be.<br />
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Alternatively, the title text could be a description of the calculations shown in the comic.<br />
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==Transcript==<br />
:[A problem is given on an arithmetic test: "4) 3x9=?". In handwriting, the student's work follows. The student has accurately reformatted the question as 3 times the square root of 81, which visually resembles the long division problem of 3 divided into 81, and then solved the latter to get 27 — the correct answer to both.]<br />
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{{comic discussion}}<br />
[[Category:Math]]</div>Kylejlinhttps://www.explainxkcd.com/wiki/index.php?title=1078:_Knights&diff=1662221078: Knights2018-11-21T00:45:26Z<p>Kylejlin: Elaborate on "0-1"</p>
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<div>{{comic<br />
| number = 1078<br />
| date = July 6, 2012<br />
| title = Knights<br />
| image = knights.png<br />
| titletext = 1. Nf3 ... ↘↘↘ 2. Nc3 ... ↘↘↘ 0-1<br />
}}<br />
<br />
==Explanation==<br />
This comic is comparing the opening moves of the game of {{w|chess}} to the opening moves of the {{w|Battle of Agincourt}}, which was fought between the English and the French in the {{w|Hundred Years War}}. In the battle, just like in the comic, the English used their longbowmen effectively, neutralizing the French knights and infantry. The two pieces that are moved out of the white side of the board are both the pieces known as the Knights. And in the actual battle, the French knights on horseback attacked first. As you can see, all the pawns on the right side of the chess board have bows.<br />
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The title text uses the abbreviations for chess moves. Nf3 = Knight to square F3. Nc3 = Knight to square C3. N = Knight because the King piece has the K [abbreviation covered]. What comes after the typical chess move is what can only be read as a hail of arrows. And the 0-1 at the end means that "Black Wins". This implies that Black resigned, as he is not in checkmate (for non-timed chess games, the only ways to win are by checkmating your opponent or by accepting their resignation).<br />
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The word "{{Wiktionary|gambit}}" means "an opening in chess, in which a minor piece or a pawn is sacrificed to gain an advantage". The usual gambit of sacrificing a pawn is subverted to be a sacrifice of a high-value piece, as an analogy of what happened at Agincourt.<br />
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==Transcript==<br />
:[A chessboard, The black pawns have all gained longbows and have specifically taken down the white knights as they move forward, without any black pieces needing to move from their opening positions. Caption below the panel:]<br />
:The Agincourt gambit.<br />
<br />
{{comic discussion}}<br />
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[[Category:Chess]]</div>Kylejlinhttps://www.explainxkcd.com/wiki/index.php?title=1084:_Server_Problem&diff=1662211084: Server Problem2018-11-21T00:30:07Z<p>Kylejlin: Add alternate interpretation</p>
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<div>{{comic<br />
| number = 1084<br />
| date = July 20, 2012<br />
| title = Server Problem<br />
| image = server_problem.png<br />
| titletext = Protip: Annoy Ray Kurzweil by always referring to it as the 'Cybersingularity'.<br />
}}<br />
<br />
==Explanation==<br />
[[Cueball]] has messed up his Linux server, {{tvtropes|WalkingTechbane|apparently not for the first time}}. [[Megan]] offers to take a look at the PC, and she casually types in 'ls' — a very basic command that ''lists'' the files in the current directory. The computer returns a bizarre error message — it trips over one of the simplest commands, indicating that Cueball's system is messed up. ''Really'' messed up.<br />
<br />
The {{w|Filesystem Hierarchy Standard#Directory structure|/usr/share}} path should indicate "architecture-independent shared data". Adobe is a software company that produces Acrobat, Flash and Photoshop. Android VM would be a virtual machine for Android. The .jar extension suggests a Java-language program. None of Adobe software, Android, or Java are needed to run 'ls'. All of the above have nothing to do with each other, with the exception that Android applications (but not core command line utilities, like ls) are written in Java. Also, basic system executables like 'ls' would never be placed within /usr/share or within some 'example' or 'doc' directory. On Linux, executables don't have filename extensions like ".exe" or ".jar". Core executables such as 'ls' are often shipped with the operating system as binaries, so the presence of `ls.jar` suggests Cueball was attempting to unorthodoxly replace the existing executable with his own Java implementation. Additionally, it would require the folder to be within {{w|PATH (variable)|$PATH}}. In other words, the error message implies that the server is in a very bad state.<br />
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In the last frame Megan is bewildered by this result and asks ''what did you do''. Cueball suggest a course of action which mimics a common error message: "______ is busy, please try again later." Obviously he has seen this type of message frequently enough to try it as a general cure in all similar cases.<br />
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Megan then tells Cueball to "shut down the system and wait for the {{w|technological singularity|singularity}}," referring to a hypothetical future event when superintelligence can be artificially created. Since future superintelligent humans/computers transcend our comprehension, we can't predict or even understand what will happen after the singularity. One interpretation is that Megan is telling Cueball that his system is such a mess that it will take a post-singularity superintelligence to fix it (or run it in its current state, as only an intelligence beyond present comprehension would be capable of doing). It also indicates that either [[1782: Team Chat]] or [[1668: Singularity]] could be the sequel to this comic.<br />
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The title text is yet another [[:Category:Protip|protip]] from [[Randall]]. {{w|Ray Kurzweil}} is an author and futurist who has {{w|Singularity Summit|talked}} and {{w|The Singularity Is Near|written}} much about a ''{{w|technological singularity}}''. Presumably, mangling the jargon (by confusing the concept of the "singularity" with the science fiction term "{{w|cyberspace}}") is something Kurzweil (as an expert) would find annoying. Also, as Randall later pointed out in [[1573: Cyberintelligence]], the word has not really been used for a decade...<br />
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==Transcript==<br />
:[Cueball at his computer calls out for Megan who comes walking in to the frame.]<br />
:Cueball: I, um, messed up my server again.<br />
:Megan: I'll take a look. You have the ''weirdest'' tech problems<br />
<br />
:[Zoom in on only Megan who uses the root prompt on the computer.]<br />
:<code><font color="gray">~#</font> ls</code><br />
<br />
:[Megan stands next to the computer, Cueball sits behind her on his chair. The computer returns the following:]<br />
:<code>/usr/share/Adobe/doc/example/android_vm/root/sbin/ls.jar:</code><br />
:<code>Error: Device is not responding.</code><br />
<br />
:[Megan turns towards Cueball who lifts his hands with palm up.]<br />
:Megan: What did you ''do!?''<br />
:Cueball: Maybe the device is busy. Should I try it later?<br />
:Megan: You should shut down this system and wait for the Singularity.<br />
<br />
== Trivia ==<br />
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* This is the first comic to have a high-resolution (pixel-doubled) version of its image.<br />
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{{comic discussion}}<br />
[[Category:Comics featuring Cueball]]<br />
[[Category:Comics featuring Megan]]<br />
[[Category:Computers]]<br />
[[Category:Linux]]<br />
[[Category:Protip]]<br />
[[Category:Singularity]]<br />
[[Category:Cueball Computer Problems]]</div>Kylejlinhttps://www.explainxkcd.com/wiki/index.php?title=1188:_Bonding&diff=1661071188: Bonding2018-11-17T22:52:12Z<p>Kylejlin: Elaborate on algorithm</p>
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<div>{{comic<br />
| number = 1188<br />
| date = March 20, 2013<br />
| title = Bonding<br />
| image = bonding.png<br />
| titletext = I'm trying to build character, but Eclipse is really confusing.<br />
}}<br />
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==Explanation==<br />
This is {{w|source code}} written in the {{w|Java (programming language)|Java programming language}} which models a parent and a child playing a {{w|Catch (game)|game of catch}}. Normally this game is played with the parent throwing a ball to their child, who catches it and throws it back, and repeated back-and-forth. The comic title "Bonding" refers to the {{w|Paternal bond|building of relationship}} between the parent and the child. The joke lies in the puns using the words <code>try</code>, <code>throw</code>, <code>catch</code>, and <code>Throwable</code>. These can refer to actions in the real-life game, but are also keywords in the Java language that are used for {{w|exception handling}}, a method of signaling error conditions and responding to them. Also, the terms "parent" and "child" are usually interpreted more abstractly in programming, as generic terms used in hierarchical {{w|Data structure|data structures}}.<br />
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The program, as written, will {{w|Recursion (computer science)|recursively}} call the <code>aim</code> method alternately on the parent and the child indefinitely, causing each to take turns throwing and catching the <code>Ball</code> object. Note that unlike the real game, this program actually has the same person both throwing and catch the same ball on their turn. The ball is passed onto the other person by ''aiming'' it at them, which causes the person to both throw and catch the ball, and ''aim'' it back, perpetuating the cycle. This program will also eventually crash with a {{w|stack overflow}} error.<br />
<br />
The title text refers to the [http://www.eclipse.org/ Eclipse IDE], which is a tool commonly used to develop software in Java. "Building character" is something that you would expect a parent to do, in order to instill in his child positive traits, such as confidence and athleticism. This is possibly a reference to Calvin and Hobbes, where Calvin's dad often encourages him to build character in a number of ways, including playing baseball. This is made more likely by other references combining technology and C+H, such as xkcd comics [[409: Electric Skateboard (Double_Comic)]], [[702: Snow Tracking]] and [[1002: Game AIs]]. However, here, "build" might also be a play on the term of "{{w|Software build|building}}" a program, while "{{w|Character_(computing)|character}}" refers to a data type in programming languages. It may also refer to the common notion that programming in C++ or Java builds character due to their powerful but sometimes finicky libraries.<br />
<br />
===Program description===<br />
To compile this {{w|Java_(programming_language)|Java}} source code, the two [http://docs.oracle.com/javase/tutorial/java/javaOO/classdecl.html classes] would need to be in a .java file.<br />
The program defines two classes (types of objects):<br />
#The Ball class [http://docs.oracle.com/javase/tutorial/java/IandI/subclasses.html extends] [http://docs.oracle.com/javase/7/docs/api/java/lang/Throwable.html Throwable], making it possible to use an instance of Ball in [http://docs.oracle.com/javase/tutorial/essential/exceptions/handling.html exception handling]. In English, this means "a Ball is a kind of Throwable object".<br />
#The P class, representing a Person, which contains the following members (attributes):<br />
#*a [http://docs.oracle.com/javase/tutorial/java/javaOO/variables.html class variable] 'target' to point to another P to aim a Ball at.<br />
#*a [http://docs.oracle.com/javase/tutorial/java/javaOO/constructors.html constructor] 'P' (in Java the constructor always has the same name as the class) used to create an instance of P and initialize its state (with a target). The keyword [http://docs.oracle.com/javase/tutorial/java/javaOO/thiskey.html this] refers to the current instance of P.<br />
#*a [http://docs.oracle.com/javase/tutorial/java/javaOO/methods.html method] 'aim' that takes an instance of Ball named 'ball' as a parameter. This contains the code to actually throw, catch, and pass the ball onto the target.<br />
#*a [http://docs.oracle.com/javase/tutorial/java/javaOO/classvars.html static] method 'main' which is called when executing this class. This is the code that sets up the game and starts the process.<br />
<br />
The program executes in the following order:<br />
#The static main method is called. It sets up the game by doing the following:<br />
##An instance of P named 'parent' is created without a target ({{w|Nullable_type|null}}) using the 'new' keyword.<br />
##Another instance of P named 'child' is created with 'parent' as its target.<br />
##The parent's target is assigned to be the child. Unlike with 'child', setting the parent's target could not be done at the moment when 'parent' was created because its target (the child) has not yet been created at the time. This is why the code for parent and child don't look alike despite this being a symmetrical setup.<br />
#The game begins by having the parent aim a new instance of Ball.<br />
#The aim method first sets up a [http://docs.oracle.com/javase/tutorial/essential/exceptions/try.html try] block to handle exceptions. A "try" block is required in Java in order to "catch" later.<br />
#Next, the Ball instance 'ball' is [http://docs.oracle.com/javase/tutorial/essential/exceptions/throwing.html thrown]. This signals an exception situation and triggers the [http://docs.oracle.com/javase/tutorial/essential/exceptions/catch.html catch] block below.<br />
#In the catch block, the aim method of the target of the P instance is called with the Ball instance (now referred to as 'b').<br />
#The target now executes its own aim method, which is the same code continuing from step 3 except with the current class instance ('this') and its target switched between the parent and the child.<br />
<br />
==Transcript==<br />
class Ball extends Throwable {}<br />
class P{<br />
P target;<br />
P(P target) {<br />
this.target = target;<br />
}<br />
void aim (Ball ball) {<br />
try {<br />
throw ball;<br />
}<br />
catch (Ball b) {<br />
target.aim(b);<br />
}<br />
}<br />
public static void main(String[] args) {<br />
P parent = new P(null);<br />
P child = new P(parent);<br />
parent.target = child;<br />
parent.aim(new Ball());<br />
}<br />
}<br />
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{{comic discussion}}<br />
[[Category:Programming]]</div>Kylejlinhttps://www.explainxkcd.com/wiki/index.php?title=166:_Misusing_Slang&diff=166106166: Misusing Slang2018-11-17T22:39:55Z<p>Kylejlin: </p>
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<div>{{comic<br />
| number = 166<br />
| date = October 4, 2006<br />
| title = Misusing Slang<br />
| image = misusing_slang.png<br />
| titletext = It slowly dawns on us that our parents knew exactly what they were doing.<br />
}}<br />
<br />
==Explanation==<br />
[[Randall]] expresses excitement for the time in the future where he can intentionally misuse modern-day slang in order to make nearby teenagers feel uncomfortable. He illustrates this by using the word "pwned," the past tense of "pwn" (from "own," as in to defeat completely): "The noob was pwned by the veteran."<br />
<br />
Many teenagers believe their parents to be not "with the times," but Randall suggests that parents actually ''do'' know what the words mean, but are acting otherwise in order to mess with their heads for their personal amusement. The title text reinforces this, as every generation has had some form of slang that they used, and it could be possible that this practice has been continued for a good while. It also suggests that the parents of teenagers may be "pwning" their children by intentionally misusing these modern-day slang.<br />
<br />
==Transcript==<br />
:The best part of getting older is gonna be intentionally misusing slang around teenagers just to watch them squirm.<br />
:Cueball: Oh man, that song is so pwned!<br />
:Teenager: ''twitch''<br />
<br />
{{comic discussion}}<br />
[[Category:Comics featuring Cueball]]<br />
[[Category:Language]]<br />
[[Category:Multiple Cueballs]]</div>Kylejlinhttps://www.explainxkcd.com/wiki/index.php?title=165:_Turn_Signals&diff=166105165: Turn Signals2018-11-17T22:35:52Z<p>Kylejlin: Add alternate interpretation</p>
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<div>{{comic<br />
| number = 165<br />
| date = October 2, 2006<br />
| title = Turn Signals<br />
| image = turn_signals.png<br />
| titletext = I'm not very good at meeting people.<br />
}}<br />
<br />
==Explanation==<br />
{{w|Automotive lighting#Turn signals|Turn Signals}} are designed to flash between 60 and 120 times per minute. Most turn signals are driven by an {{w|electromechanical}} device. Due to manufacturing tolerances, battery state of charge, ambient temperature, and various other factors, two different turn signals rarely flash at the same rate, even among cars of the same make and model. Having two cars with turn signals flashing at the same rate would be a rare event.<br />
<br />
[[Cueball]] (or maybe Randall) notices this event, and expresses his excitement to the driver of the other car, despite being stopped at an intersection. The other driver is confused by this. Turn signal frequency is something that most people don't take notice of. Cueball, however, takes it as an opportunity to strike up a conversation and make a new friend. The title text refers to the fact that this is probably not a good strategy for making friends.{{Citation needed}}<br />
<br />
The beat frequency is the rate at which two frequencies transition from being ''{{w|phase (waves)|in phase}}'' with each other to being ''out of phase'' and then to being ''in phase'' again. In other words, two turn signals that begin by flashing together will transition to flashing opposite each other and then back to flashing together, and the rate at which this process cycles is the beat frequency. Because the beat frequency is simply the ''difference'' between the two turn signal frequencies, two turn signals whose frequencies are closer together will take longer to pass through the in-phase/out-of-phase cycle, and two signals whose frequencies are identical would take an infinite time (i.e., their relative phase never changes). The beating of turn signals is an easy phenomenon to observe when one is stopped at a {{w|traffic light}} with nothing to do but watch the flashing turn signals, and it is the lack of beating that Cueball noticed and excitedly reported.<br />
<br />
The title text suggests that the character presumed to be Cueball may be Randall.<br />
<br />
==Transcript==<br />
:[Two cars are seen sitting at a red light. One person is seen walking from his car up to the driver of the car in front of him. The turn signals of both cars seem to be blinking at the same time.]<br />
:Person in Street: Hey, our turn signals are in sync!<br />
:Person in Car: What the hell?<br />
<br />
:Person in Street: Usually they're at least a little off. But I've been watching like 30 seconds and haven't seen any beat frequency!<br />
:Person in Car: Who are you?<br />
<br />
:Person in Street: You know, from the beat frequency you can tell the difference in timing of the two signals.<br />
:Person in Car: ...<br />
:Person in Street: But ours are the same!<br />
:Person in Car: ...<br />
:Person in Street: So, wanna hang out later?<br />
<br />
{{comic discussion}}<br />
[[Category:Comics featuring Cueball]]<br />
[[Category:Comics with color]]<br />
[[Category:Traffic light]]<br />
[[Category:Multiple Cueballs]]</div>Kylejlinhttps://www.explainxkcd.com/wiki/index.php?title=1708:_Dehydration&diff=1660771708: Dehydration2018-11-17T06:57:31Z<p>Kylejlin: Remove irrelevant detail about 1744: Metabolism</p>
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<div>{{comic<br />
| number = 1708<br />
| date = July 18, 2016<br />
| title = Dehydration<br />
| image = dehydration.png<br />
| titletext = I don't care what the research says. Everybody knows you should drink 3,000 glasses of water a day and change your oil every 8 miles.<br />
}}<br />
<br />
==Explanation==<br />
This comic plays on the idea that there is little to no consensus in the scientific community with regard to the amount of water a person should drink per day. In the first panel [[White Hat]] presents [[Cueball]] with an innocent and sensible suggestion (although controversial) that people should drink six glasses of water per day. In the second panel, more characters join the discussion, an off-panel voice claims the most {{w|Drinking_water#Requirements|common misconception}} of eight glasses a day, a number which is not supported by scientific research. [[Ponytail]] again goes two higher with ten highlighting the existence of a wide range of so-called 'optimum' liquid consumption 'rule-of-thumb'. Implied here is the variety of health-related books, articles, blogs or other literature published that self-proclaims an optimum drinking formula.<br />
<br />
The first sign of absurdity also arises here in the second panel when [[Black Hat]] posits that we need 5 glasses of water every minute. This equates to 7200 glasses of water a day, and using an often cited "standard definition of a glass"[https://www.quora.com/One-glass-of-water-is-how-many-ounces], [https://answers.yahoo.com/question/index?qid=20061002110517AAltamZ], [http://www.sparkpeople.com/ma/How-many-ounces-is-a-glass-of-water?/7/1/27943956] being equal to 8 oz (236 ml), Black Hat is suggesting that we should each drink 1.7 cubic meters (1700 liters) of water a day, not only curing {{w|dehydration}} but also causing {{w|water intoxication}}. This is a typical Black Hat kind of statement that he uses to further emphasizes the absurdity of the problem at hand.<br />
<br />
Some time later [[Megan]], despite having read through all studies on dehydration (or low-grade dehydration in particular), still has not come to a solid conclusion. She becomes dizzy, admitting that she's been so focused on her work, she has ironically [http://tvtropes.org/pmwiki/pmwiki.php/Main/ForgetsToEat forgotten to eat or drink]. Her personal experience with dehydration prompts someone off-panel to get some water, but since she couldn't find any consensus in her research, she asks how many glasses they should bring her. Presumably to avoid the question of "how many glasses" entirely, Cueball finally suggests that she should drink straight from the tap, a (tenuously) sincere suggestion seeing her dehydration and following the good advice to drink when you are thirsty until that state has been absolved. In the title text of [[1744: Metabolism]], released less than 3 months after this one, Cueball mentions how he starts to feel bad if he refrains from drinking, just like Megan here.<br />
<br />
The title text contains a mix-up between two often stated intervals; drinking eight glasses of water per day (which makes no sense, see above) and changing the engine oil every {{w|3,000_mile_myth|3000 miles}} (almost 5000 km) which may be a good rule, but not a necessity. Obviously it's impossible to drink 3000 glasses of water, and changing the oil every eight miles (about 13 km) would make driving a car very impractical.<br />
<br />
The subject of this comic has been graphed in [[715: Numbers]] and mentioned in the what if? ''{{what if|74|Soda Planet}}'':<br />
<blockquote><br />
The question of how much water we should drink per day is the subject of furious debate—the "8 glasses" thing seems to be a myth—but the amount of water we actually drink per day seems to be about a liter.<br />
</blockquote><br />
<br />
Later, in the what if? ''{{what if|91|Faucet Power}}'', [[Randall]] comments on the preference for even numbers in the graph, and writes:<br />
<blockquote><br />
The only real solid advice I've heard is that if you're thirsty, you should drink some water.<br />
</blockquote><br />
''How many glasses is "some water"'' remains an open question...<br />
<br />
[[Beret Guy]] and Megan are participants of a thought experiment concerning glasses of water and vacuum in the [[what if?]] ''{{what if|6|Glass Half Empty}}''.<br />
<br />
And the six glasses of water that this comic began with is also mentioned later in [[1853: Once Per Day]].<br />
<br />
This is a rare example of a normal xkcd comic of few panels manages to use five of the seven [[Template:navbox characters|major characters]] who actually interact. It is the [[:Category:Characters with Hats|first comic]] where Black Hat has spoken (or directly interacted) with White Hat. Until this comic, they have only appeared together in complicated/large drawings where there is no interaction between the two. The only other time this has happened is in [[1881: Drone Training]].<br />
<br />
==Transcript==<br />
:[White Hat and Cueball standing together.]<br />
:White Hat: Many people are mildly dehydrated. And don't realize it. You should drink at least six glasses of water per day.<br />
<br />
:[A voice comes from off-panel to the left as Ponytail enters from the left and Black Hat from the right in this frameless panel.]<br />
:Off-panel voice: No, ''eight'' glasses!<br />
:Ponytail: I heard ten.<br />
:Black Hat: You need to drink at least five glasses of water per minute.<br />
<br />
:[Megan is standing to the left holding a book or a thick binder along her side while holding up a finger with the other hand. A question comes from off-panel to the right. Above her a caption is written in a small frame that breaks the top of this panel's frame:]<br />
:Later:<br />
:Megan: Okay, I just read through every study I could find to try to figure out whether low-grade dehydration is even a real thing.<br />
:Off-panel voice: What did you learn?<br />
<br />
:[Megan looking downwards, has two starbursts a circles and two dots above her head signifying dizziness. Cueball stands to the right as another voice comes from off-panel to the right.]<br />
:Megan: If you spend all day doing research and forget to eat or drink, you start to feel pretty bad.<br />
:Off-panel voice: I'll get some water.<br />
:Megan: ''But how many glas'' - Whoa, feeling dizzy.<br />
:Cueball: Maybe you should just drink straight from the tap.<br />
<br />
{{comic discussion}}<br />
[[Category:Comics featuring Cueball]]<br />
[[Category:Comics featuring White Hat]]<br />
[[Category:Comics featuring Ponytail]]<br />
[[Category:Comics featuring Black Hat]]<br />
[[Category:Comics featuring Megan]]</div>Kylejlinhttps://www.explainxkcd.com/wiki/index.php?title=1696:_AI_Research&diff=1660751696: AI Research2018-11-17T06:47:21Z<p>Kylejlin: elaborate on lambda calculus</p>
<hr />
<div>{{comic<br />
| number = 1696<br />
| date = June 20, 2016<br />
| title = AI Research<br />
| image = ai_research.png<br />
| titletext = Lambda calculus? More like SHAMbda calculus, amirite?<br />
}}<br />
<br />
==Explanation==<br />
Developing {{w|Artificial Intelligence}} (AI) has been a challenge for a long time. Even to develop one with the intelligence of a six-year-old child would be a great milestone, and presumably a stepping stone on the path to making one with the intelligence of an adult human.<br />
<br />
In this comic, [[Randall]]/[[Cueball]] jokingly suggests that in order to accomplish this goal, one can give him an AI that's already as smart as an adult, and let him teach it childish and silly things. He is shown teaching it dumb jokes, much like the ones a sassy six-year-old would make, as the first {{w|Flatulence humor|"fart" joke}} where ''art''ificial is changed to ''fart''ificial.<br />
<br />
The humor in the comic is that Randall is essentially accomplishing the present goal of a six-year-old-equivalent AI by starting with the final goal, which is a full human intelligence, and making it dumber, just by teaching it poor humor. This is not unlike the old joke, "The easiest way to make a small fortune on Wall Street [or similar] is to start with a large one."<br />
<br />
The specific situation may also be a reference to {{w|Tay (bot)|Tay}}, a Microsoft chatbot that was taught to {{w|internet troll|troll}} within hours of its exposure to the public.<br />
<br />
"[http://www.urbandictionary.com/define.php?term=up%20dog Updog]" refers to a light-hearted {{w|practical joke}} in which the perpetrator casually uses the neologism 'updog' in a sentence ("Hey, I'm going to get some updog, you want any?"). The unsuspecting listener is expected to be curious about the meaning of the neologism and ask the perpetrator its meaning, specifically in the format "What's 'updog'?", inadvertently invoking the highly casual greeting of "What's up, dawg?". The perpetrator then draws attention to this by replying along the lines of "Not much, you?", causing the target to realize the foolish thing they just said. Other neologisms used in the context of this joke include 'updoc', 'snoo', and 'samatta' ("[https://www.youtube.com/watch?v=pwLn_His9Yw What's up, doc?]", "What's new?", and "What's the matter?", respectively). Updog is mainly an American joke not particularly well known in other English-speaking countries.<br />
<br />
In the title text there is a joke on {{w|lambda calculus}}, where ''lam''bda is changed to ''SHAM''bda. Lambda calculus is an area of mathematical logic and theoretical computer science. It is a formal language which can express computation and evaluation. It is Turing Complete, which means it can do any computation which can be executed by a computer. However, it is very simple, consisting only of two primitive notions: ''abstraction'', which is forming a unary function (a function that takes one argument) and ''application'' which is applying a function to an input value. For example, a function which squares a given number can be written λx.x². Here the ''λ'' indicates an abstraction (hence the name ''lambda calculus''), the ''x'' is the input value and the output is ''x²''. As an example of application, if we apply this function to 5, we get (λx.x²)(5) = 5² = 25. The title text makes fun of this by inserting the word "Sham" into the phrase, a word used to describe a trick or con; essentially, it denies that such calculus is useful or valid.<br />
<br />
The title text finishes with ''[http://da.urbandictionary.com/define.php?term=amirite amirite]'', short for ''am I right?'' which is often used to finish sentences on web forums, to prevent anyone saying you are wrong. Not very mature to use in a serious discussion, so very fit to use for a AI that tries to emulate the intelligence of a six-year-old.<br />
<br />
''AI tip'' is yet another [[:Category:Tips|tips comic]].<br />
<br />
==Transcript==<br />
:[Cueball (representing Randall, or at least the person who wrote the caption) is standing in front of a computer console displaying AI, talking to it. The computers reply is indicated to come from the console with a zigzag line, rather than the straight lines for Cueball.]<br />
:Cueball: Then you say "More like ''fart''ificial intelligence!"<br />
:Computer: Understood.<br />
:Cueball: Great! Now let me teach you about "updog".<br />
<br />
:AI tip: To develop a computer with the intelligence of a six-year-old child, start with one as smart as an adult and let me teach it stuff.<br />
<br />
{{comic discussion}}<br />
<br />
[[Category:Comics featuring Cueball]]<br />
[[Category:Tips]]<br />
[[Category:Artificial Intelligence]]<br />
[[Category:Computers]]<br />
[[Category:Math]]</div>Kylejlinhttps://www.explainxkcd.com/wiki/index.php?title=1744:_Metabolism&diff=1660671744: Metabolism2018-11-16T23:21:20Z<p>Kylejlin: Cite eating disorders as a possible cause for people not gaining weight in addition to chronic disease and parasite infection</p>
<hr />
<div>{{comic<br />
| number = 1744<br />
| date = October 10, 2016<br />
| title = Metabolism<br />
| image = metabolism.png<br />
| titletext = I have this weird thing where if I don't drink enough water, I start feeling bad and then die of dehydration.<br />
}}<br />
<br />
==Explanation==<br />
Eating is fundamentally a process where energy from food gets absorbed into the body in order to drive every cellular process in the body. Energy that is absorbed but not needed in the short term gets converted and stored as body fat. This is called {{w|metabolism}}. Consuming too much food and not exercising enough are major factors for {{w|obesity}}, which is a problem in many first world countries today, {{w|Obesity in the United States|especially in the United States}}.<br />
<br />
For obese people, losing weight is often an enormously difficult task. Standing in stark contrast, there are also lean people who do not seem to ever gain any weight even though they appear to eat whatever and however much they want. This leads some people (including the lean people themselves) to believe that one can have a special {{w|metabolism}} where excess food energy somehow does not affect the body. This belief is common, though not supported by scientific evidence. The comic makes fun of that kind of notion. While [[Cueball]] describes to [[White Hat]] how his metabolism is "special" (the phrase "one of those" implicitly meaning unusual), he is in fact only describing the normal case: no matter what he eats, his body converts the food to energy and stores any excess food as fat which stays in his body for future use.<br />
<br />
The title text stretches this further, telling about the normal habit of drinking water (and the consequences of not drinking it) as something odd. Starting to feel bad at first and eventually dying if refraining from drinking for too long a time are perfectly normal consequences of dehydration. This was also touched upon in [[1708: Dehydration]], in which Megan spent all day researching whether low-grade dehydration is really a thing -- ironically forgetting to eat or drink at all, to predictable results.<br />
<br />
Obesity has only fairly recently become a public health issue due to lifestyle changes brought on by technologies such as industrialization and trade. Human bodies evolved under conditions where it was hard to ever find enough to eat, so to store as much excess energy as possible as fat was a beneficial adaptation. Historically, stored fat would be consumed during hard times that was sure to come. The act of collecting food through farming or hunting/gathering also demanded physical labor which limited the amount of excess energy that would remain. In comparison, people nowadays hardly need to expend any energy to buy their food from a nearby market. They also have much more sedentary lifestyles and rarely ever go hungry. Without an active commitment to exercise more or eat less, there would almost never be a shortage of energy and no chance for body fat to be used. Randall has previously shown how bad his health becomes when he starts eating lots of fat (or sweet) food in [[418: Stove Ownership]].<br />
<br />
There are many rational explanations for why some people might not gain weight despite eating a lot. For example, it's possible that they only eat a lot during special occasions and social gatherings, where they are easily '''seen''' eating. On more private occasions when no one is watching, they could just as well eat much less or even skip entire meals. They might also lead a much more active lifestyle and thus require more energy than an average person despite their thin appearance. Other less pleasant reasons might include chronic diseases, parasite infections, or eating disorders.<br />
<br />
This is the second comic in a row about food, the previous being [[1743: Coffee]].<br />
<br />
==Transcript==<br />
:[Cueball, on the left, and White Hat are sitting on chairs on either side of a table, facing each other. They each have plates of food and glasses of some beverage set in front of them. Each has picked up a portion of food on a fork to eat it.]<br />
<br />
:Cueball: I have one of those metabolisms where I can eat whatever I want and my body converts it to energy and stores the excess as fat.<br />
<br />
{{comic discussion}}<br />
<br />
[[Category:Comics featuring Cueball]]<br />
[[Category:Comics featuring White Hat]]<br />
[[Category:Food]]</div>Kylejlinhttps://www.explainxkcd.com/wiki/index.php?title=explain_xkcd:Sandbox&diff=166064explain xkcd:Sandbox2018-11-16T23:06:18Z<p>Kylejlin: Add link to the explain xkcd Chrome extension</p>
<hr />
<div>__NOINDEX__<br />
Make changes, try things out, or just have fun with the wiki here! Just leave everything above the line alone, please.<br />
[http://www.explainxkcd.com/wiki/index.php?title=explain_xkcd:Sandbox&action=edit&oldid=91667 clear sandbox]<br />
------<br />
What is your favorite comic on xkcd? I like [[977: Map Projections]].<br />
<br />
Checkout the [https://chrome.google.com/webstore/detail/explain-xkcd/fpmkngibepdfagmmmenjbfmgohlddakg?gl=001& explain xkcd Chrome extension]!</div>Kylejlin