explain xkcd - User contributions [en]

1133: Up Goer Five

2013-08-14T04:59:41Z

24.142.134.100: 547

{{comic
| number = 1133
| date = November 12, 2012
| title = Up Goer Five
| image = up goer five.png
| titletext = Another thing that is a bad problem is if you're flying up to space and the parts start to fall off your space car in the wrong order. If that happens, it means you won't go to space today, or maybe ever.
}}

==Explanation==
Most of the jargon used in rocket science is not among the most commonly used words in everyday life. This comic is a commentary on the absurdity of boiling down technical explanations for lay people, with Randall challenging himself to "translate" the blueprints using only the one thousand most commonly-used words in the English language.

This comic is a diagram of the {{w|Saturn V}} rocket, "Saturn" isn't a very common word apparently, and neither is rocket, so [[Randall]] decided to use "Up Goer" which is a fair approximation of a craft designed to lift a payload from the earth to space. The Saturn V vehicle, which was in use by {{w|NASA}} from 1967 to 1972, is the vehicle as a whole. The engines of the Saturn V (the part that makes it go up) were divided into three stages. The first stage ({{w|S-IC}}) had five {{w|F-1 (rocket engine)|F-1}} engines which burned {{w|RP-1|refined kerosene}} mixed with oxygen as its fuel. That stage burned for 2 minutes 48 seconds and pushed the whole thing up about 61 kilometers (~38 miles) into the sky. After it fell away the {{w|S-II}} stage was activated. It used 5 {{w|J-2 (rocket engine)|J-2}} engines in the same configuration as the F-1s, and burned {{w|liquid hydrogen}} mixed with {{w|liquid oxygen}} for 6 minutes 35 seconds pushing the astronauts up to 184 kilometers (114.5 miles). The third stage ({{w|S-IVB}}) was a single J-2 engine burning liquid hydrogen and liquid oxygen. This stage was used in two parts, the first was to put the spacecraft into a stable orbit around Earth to perform a systems check and make sure the craft will be safe for going to the moon. This would usually take three orbits around Earth. As they came around the Earth they would burn the second part of the fuel, which is called a {{w|trans-lunar injection}} which put them on course for the moon. The first burn took 2 minutes 45 seconds, which put them in orbit 185 kilometers (115 miles) high.

It was first used as the launch vehicle for the {{w|Apollo 4}} mission, and it was used as the launch vehicle for most of the subsequent {{w|Apollo mission}}s (the exceptions being Apollo 7, Skylab 2-4, and the Apollo-Soyuz Test Project missions, which were launched using the smaller {{w|Saturn IB}} launch vehicle). One of the last missions of this design was the unmanned launch of {{w|Skylab}}, the U.S.'s first space station; for this payloader configuration, the Saturn V launch vehicle was officially designated the {{w|Saturn INT-21}}.

The Service Module (SM) Oxygen tanks, have a note that "This part had a ''VERY'' big problem once". This is a reference to the {{w|Apollo 13}} mission. 55 hours after launch, mission control requested the oxygen tanks contents be stirred to get an accurate reading of its contents. There was {{w|Apollo 13#Oxygen tank incident|a large bang}}, and power fluctuated throughout the craft. NASA had to scramble to ensure the safe return of the astronauts. Needless to say, the moon landing for that mission was canceled.

The {{w|Hindenburg disaster}} is referenced in the text "The kind of air that once burned a big sky bag and people died and someone said "oh, the [humans]!". The term "big sky bag" is used as the closest approximation of {{w|zeppelin}} which is a big bag filled with a lighter-than-air gas which makes the whole contraption float. The {{w|LZ 129 Hindenburg|Hindenburg}} on the day of the disaster was filled with {{w|hydrogen}}, despite being initially designed for use with {{w|helium}}. Helium is much less prone to catching fire, but was unavailable due to a US export ban on the element. The risks seemed acceptable at the time because the Germans had a history of flying hydrogen-based passenger airships. The original quote is "Oh, the humanity!" [http://www.youtube.com/watch?v=F54rqDh2mWA] (skip to 0:47 for the quote).

The bottom tank, which [[Randall]] describes as "...full of that stuff they burned in lights before houses had power" is highly refined kerosene, called {{w|RP-1}}, it is similar to jet fuel, burns well and is not likely to explode; unlike {{w|liquid hydrogen}}, which is much more likely to explode.

An earlier flirt with simple words is in [[547: Simple]].

==Transcript==
:US Space Team's Up Goer Five
:The only flying space car that's taken anyone to another world (explained using only the ten hundred words people use the most often)
:[A list of Saturn-V parts, top to bottom, with their "Up Goer" description follows]
:[Launch Escape System (LES)]: Thing to help people escape really fast if there's a problem and everything is on fire so they decide not to go to space
::[LES side nozzle]: Thing to control which direction the escaping people go
::[LES fuel]: Stuff to burn to make the box with the people in it escape ''really fast''
::[LES bottom nozzles]: Place where fire comes out to help them escape
:[Apollo spacecraft]
::[Command Module (CM)]: Part that flies around the other world and comes back home with the people in it and fall in the water.
:::[CM capsule parts]: People box, door, chairs
::[Service Module (SM)]: Part that goes along to give people air, water, computers and stuff. It comes back home with them but burns up without landing.
:::[SM oxygen tanks]: Cold air for burning (and breathing). This part had a ''VERY'' big problem once.
::[Lunar Module (LM)]: Part that flies down to the other world with two people inside
:::[LM descent stage]: Part that stays on the other world (it's still there)
:::[LM feet]: Feet that go on the ground of the other world
:[Instrument Unit]: Ring holding most of the computers
:[S-IVB third stage]: Part that falls off third (this part flew away from our world into space and hit the world we were going toward)
::[Fuel tanks]: Wet and ''very'' cold
:::[Liquid hydrogen (LH2) tank]: The kind of air that once burned a big sky bag and people died and someone said "Oh, the [humans]!" (used for burning)
:::[Liquid oxygen (LOX) tank]: The part of air you need to breathe, but not the other stuff (used for burning)
:::[Helium pressurizing tanks]: Things holding that kind of air that makes your voice funny (it's for filling up the space left when they take the cold air out to burn it.)
::[J-2 engine nozzle]: Fire comes out here
:[S-II second stage]: Part that falls off second
::[LH2 tank]: More sky bag air (for burning) (cold + wet)
::[LOX tank]: More breathing-type air (for burning) (cold + wet)
::[Tank-to-engine fuel lines]: Thing that brings in cold wet air to burn
::[J-2 engine nozzles (qty. 5)]: Fire comes out here
:[S-IC first stage]: Part that falls off first
::[LOX tank]: More breathing-type air (for burning) (cold + wet)
::[Helium pressurizing tank]: More funny voice air (for filling up space)
::[LOX fill line]: Opening for putting in cold wet air
::[RP-1 fuel tank]: This is full of that stuff they burned in lights before houses had power.It goes together with the cold air when it's time to start going up.
::[F-1 engine nozzles (qty. 5)]: Lots of fire comes out here.
:[Bottom of spacecraft]: This end should point toward the ground if you want to go to space. If it starts pointing toward space you are having a bad problem and you will not go to space today.

==External links==
*[http://history.msfc.nasa.gov/saturn_apollo/documents/First_Stage.pdf First Stage Fact Sheet]
*[http://history.msfc.nasa.gov/saturn_apollo/documents/Second_Stage.pdf Second Stage Fact Sheet]
*[http://history.msfc.nasa.gov/saturn_apollo/documents/Third_Stage.pdf Third Stage Fact Sheet]
*[http://splasho.com/upgoer5/ The Up-Goer Five Text Editor]

{{comic discussion}}
[[Category:Comics with color]]
[[Category:Charts]]
[[Category:Language]]
[[Category:Physics]]

1124: Law of Drama

2013-08-14T04:53:45Z

24.142.134.100: 592

{{comic
| number = 1124
| date = October 22, 2012
| title = Law of Drama
| image = law of drama.png
| titletext = 'Drama' is just 'people being upset,' when someone says they're always surrounded by drama and they just ignore it, it starts to make sense that their strategy might be backfiring.
}}

==Explanation==
The comic comments on how often people who label themselves as an innocent party in a debate are often far from it. Essentially, [[Randall]] seems to be graphically stating that people who claim to want to avoid drama are invariably associated with it. (But since {{w|correlation does not imply causation}}, it might be a leap — at least scientifically speaking — to actually surmise that they're the cause of it.)

[[592: Drama]] gives another, not dissimilar, take on drama avoidance.

==Transcript==
:[A cartesian graph labelled 'How often someone declares that they hate "drama" and always avoid it' on the x axis and 'Rate at which they create drama' labelled on the y axis. The graph is a slightly exponential curve sloping upwards.]

{{comic discussion}}
[[Category:Charts]]
[[Category:Psychology]]

898: Chain of Command

2013-08-14T04:47:09Z

24.142.134.100: source and explain quote

{{comic
| number = 898
| date = May 13, 2011
| title = Chain of Command
| image = chain of command.png
| titletext = Themistocles said his infant son ruled all Greece -- "Athens rules all Greece; I control Athens; my wife controls me; and my infant son controls her." Thus, nowadays the world is controlled by whoever buys advertising time on Dora the Explorer.
}}

==Explanation==
{{w|Themistocles}} was an Ancient Greek politician and this comic and image text are about uncommon chains of command.

The President of the United States is at the top of the US Nuclear Chain of Command, but the engineer is ''de facto'' above him because the engineer is in charge of configuring how the button works. The "Red Button" is usually a worst case scenario as it launches all nuclear capabilities.

In the image text is a similar joke placed at the top of the chain of command, this time in Ancient Greece. The title text refers to Plutarch's [http://penelope.uchicago.edu/Thayer/E/Roman/Texts/Plutarch/Lives/Themistocles*.html#p53 ''Life of Themistocles'']:

Of his son, who lorded it over his mother, and through her over himself, he said, jestingly, that the boy was the most powerful of all the Hellenes; for the Hellenes were commanded by the Athenians, the Athenians by himself, himself by the boy's mother, and the mother by her boy.

This paradoxical situation applies in many other fields. In a major corporation commercially sensitive information is generally hidden from employees at lower levels but available to management, but the database administrator (who usually sits low on the hierarchy and doesn't manage any other employees) can access not only the sensitive information but the raw data that it's calculated from. Not only that, but the database administrator is usually responsible for controlling who has access to the information - making him/her the most powerful person in the company (as far as the database is concerned). Many managers think of themselves as being "above" engineers and have trouble coming to grips with this concept.

==Transcript==
:[A flowchart shows the President at the top, with an arrow to the Secretary of Defense, and then fourteen arrows leading to a series of boxes labeled Unified Combat Commanders. On the side, a box with a dotted outline has a dotted arrow leading to the president. It's labeled "Engineer Who Installed the Red Button."]
:US NUCLEAR CHAIN OF COMMAND

{{comic discussion}}
[[Category:Charts]]
[[Category:Politics]]

Category:Zombies

2013-08-14T04:31:06Z

24.142.134.100: quick category

These comics feature {{w|Zombie|zombies}}, either as monsters (348, 734) or historical figures brought to life:
* Erdős: 599
* Feynman: 397
* Curie: 896

348: Close to You

2013-08-14T04:30:58Z

24.142.134.100: zombies

{{comic
| number =348
| date =November 23, 2007
| title =Close to You
| image =close_to_you.png
| titletext =We should probably talk about this before the wedding.
}}

==Explanation==
This is Randall's version of the popular {{w|Carpenters (band)|Carpenters}} song, "{{w|(They Long to Be) Close to You}}". The actual first verse goes like this:

:''Why do birds suddenly appear''
:''Every time you are near?''
:''Just like me, they long to be''
:''Close to you''

In this parody, the reason birds suddenly appear whenever the girl is near is because the girl is a zombie, and those are turkey vultures, carrion birds that prey on the flesh of dead bodies. It's probably a good idea to talk about this before the wedding, as the title text says.

==Transcript==
:[Cueball singing to zombie Megan.]
:Cueball: Why do birds suddenly appear
:Cueball: Every tiiiime you are neeear
:Cueball: Wait, are those turkey vultures?
:Cueball: Okay, listen, are you a zombie?
:Megan: Hurrghhh...

{{comic discussion}}
[[Category:Comics featuring Cueball]]
[[Category:Songs]]
[[Category:Zombies]]

599: Apocalypse

2013-08-14T04:30:04Z

24.142.134.100: zombies

{{comic
| number = 599
| date = June 19, 2009
| title = Apocalypse
| image = apocalypse.png
| titletext = I wonder if I still have time to go shoot a short film with Kevin Bacon.
| imagesize =
}}

== Explanation ==
According to Wikipedia, {{w|Paul Erdős}} (26 March 1913 – 20 September 1996) was a Hungarian mathematician who published more papers than any other mathematician in history, working with hundreds of collaborators.

An in-joke developed among mathematicians called the {{w|Erdős number}}. By definition, Erdős has an Erdős number of 0. Everyone who has co-written a mathematical paper with Erdős has an Erdős number of 1. Everyone who collaborated with them (but not Erdős himself) is assigned an Erdős number of 2. In general, if ''k'' is the minimal Erdős number of all the people you've written papers with, your Erdős number is ''k'' + 1. The Erdős number is the length of the shortest "chain" from you to Erdős.

Not everyone has an Erdős number, meaning that they don't have any chain linking them to Erdős. Most non-mathematicians do not have an Erdős number.

In this comic, the apocalypse happens. [[Cueball]] quickly writes a math paper and gets everyone from the math dept. to sign it. Then he gets the resurrected Erdős to sign it. This way everyone from the math dept. has an Erdős number of 1.

Paul Erdős described people who had stopped doing mathematics as "dead."

The title text mentions a similar (and less esoteric) meme called {{w|Six degrees of Kevin Bacon}}. This time, the chain's center is actor {{w|Kevin Bacon}}, and the links are formed by two people appearing in the same movie.

==Transcript==
:[Scene of meteors showering the earth.]

:Beret Guy: The apocalypse! The skies burn, the seas turn to blood, and the dead walk the earth!

:[Cueball and Beret Guy.]
:Cueball: The dead what?
:Beret Guy: Walk the earth!

:[Cueball running.]
:Cueball: I have to go.

:[Cueball scribbling at a table. Mathematical symbols and equations are above Cueball's head.]
:''Scribble scribble''

:[Cueball running, paper in hand.]

:[Cueball opening door labelled "Math dept."]
:Cueball: The dead return!
:Cueball: Everyone, quick, get your names on here!

:[People lining up.]
:Woman signing paper: At last!
:Man in line: I hope there's still time!

:[Cueball running.]

:[Cueball at a cemetery.]
:Rising dead: ''Hurrghhh''

:[Cueball finds a man rising from his grave.]

:Cueball: Paul Erdős?
:Erdős: Yes?
:Cueball: We need you to sign this.

{{Comic discussion}}
[[Category:Comics featuring Beret Guy]]
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Megan]]
[[Category:Comics featuring Ponytail]]
[[Category:Comics with color]]
[[Category:Math]]
[[Category:Zombies]]

734: Outbreak

2013-08-14T04:26:21Z

24.142.134.100: zombies

{{comic
| number = 734
| date = April 30, 2010
| title = Outbreak
| image = outbreak.png
| titletext = Let's get dinner after we promptly destroy all the X-7 we've manufactured.
}}

==Explanation==
Patient Zero is the usual terminology for the first patient tested or infected with an outbreak-style infection.

Also, it seems every zombie movie is rife with terrible mistakes which allow the slowly lurching zombies (or outbreak) to escape and spread. For example, the nurse will look at the chart and not look at the patient and then walk away. The security guard will cross the hall 2 seconds after the zombie has left the doorway.

This sounds more realistic...blast the zombie, destroy the toxin and then go on a date.

==Transcript==
:[Two scientists, Cueball and Megan, stand outside a lab. A zombie is visible through the window.]
:The outbreak started with Patient Zero...
:Cueball: He was exposed to toxin X-7—now he's a bloodthirsty monster!
:Megan: Has he been in isolation?
:Zombie: Braaains!

:Cueball: Yes, but I can't hold this door for long!
:Megan: Hang on, I've got a gun in my truck.
:[She runs off.]
:Zombie (through door): <<wham>>

:[Cueball opens the door as Megan shoots through it.]
:<<BLAM>>

:And ended with Patient Zero five minutes later.
:Cueball: So, I never got your name. I'm Ryan.
:Megan: Laura.
:The remaining 90 minutes of the movie will be a romantic comedy.

{{comic discussion}}
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Megan]]
[[Category:Comics with color]]
[[Category:Zombies]]

397: Unscientific

2013-08-14T04:26:08Z

24.142.134.100: zombies

{{comic
| number = 397
| date = March 17, 2008
| title = Unscientific
| image = unscientific.png
| titletext = Last week, we busted the myth that electroweak gauge symmetry is broken by the Higgs mechanism. We'll also examine the existence of God and whether true love exists.
}}

==Explanation==
In the first and second frames, [[Megan]] can be seen accusing {{w|MythBusters}} of not actually "doing science" because of its lack of {{w|scientific rigor|rigor}} - a debate beyond the scope of this Wiki. The zombie of deceased physicist, {{w|Richard Feynman}}, comes to explain to [[Megan]] that she has failed to recognize the purpose of MythBusters. He explains that MythBusters is only meant to get people to accept and understand the basics of science, and that more complex lessons (such as on rigor) would be wasted on people who don't understand those basics.

In the last frame, [[Cueball]] attempts to save himself and [[Megan]] from zombie Feynman by implying that physicists, being extremely intelligent, would have more desirable brains. Also, being a lab, the number of brains available would be higher than just two. Feynman's closing remark implies that string theorists are less intelligent that other types of physicists. This notion fits appropriately with Feynman's description of the core of science. Moreover, Feynman's own career involved applying physics to real world applications (such as for the Manhattan Project), whereas the work of string theorists is theoretical and untested.

It is also a pun on {{w|Membrane_(M-theory)|M-theory}} (also called Brane theory), a part of string theory, which some argue is impossible to test scientifically.

The title text starts by rebounding against the complaint of validity as science by purportedly tackling a ''really'' big scientific enquiry. Then veers away into two far more esoteric proposed fields of study, of which at least one is not even determinable by the scientific method.

==Transcript==
:TV: Can a ninja catch an arrow? On this episode, we'll find out!
:Cueball: Mmm, science.
:Megan: Hey, Mythbusters is entertaining, but it's not science.
:Zombie Feynman: ''BRAAAIIIINNS''...
:Cueball: Zombie Feynman!
:Zombie Feynman: You got a problem with Mythbusters?
:Megan: They fail at basic rigor!
:Zombie Feynman: "Ideas are tested by experiment." That is the core of science. Everything else is bookkeeping.
:Zombie Feynman: By teaching people to hold their beliefs up to experiment, ''Mythbusters'' is doing more to drag humanity out of the unscientific darkness than a thousand lessons in rigor. Show them some love.
:Zombie Feynman: Anyway, back to zombie stuff. I hunger for ''BRAAAAAIIINNS!''
:Cueball: Try the physics lab next door.
:Zombie Feynman: I said brains. All they've got are string theorists.

{{comic discussion}}
[[Category:Comics featuring real people]]
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Megan]]
[[Category:Zombies]]

896: Marie Curie

2013-08-14T04:25:43Z

24.142.134.100: zombies

{{comic
| number = 896
| date = May 9, 2011
| title = Marie Curie
| image = marie curie.png
| titletext = Although not permanently.
}}

==Explanation==
In this comic, [[Ponytail]] is standing (possibly by herself and talking to herself) and looking at a picture of {{w|Marie Curie}}. When she mentions Marie Curie's name, Zombie Marie Curie comes forth to give some life lessons and inspiration.

Marie Curie pioneered research on radioactivity and as it says in the comic she earned two nobel prizes. She died from {{w|aplastic anemia}} contracted from exposure to radiation — although in the image text it says that it does not kill you permanently, because you come back as a zombie.

Everything that Zombie Marie Curie says about {{w|Emmy Noether}} and {{w|Lise Meitner}} above is true as well.

==Transcript==
:Ponytail: My teacher always told me that if I applied myself, I could become the next Marie Curie.
:Zombie Marie Curie: You know, I wish they'd get over me.

:Ponytail: Zombie Marie Curie!

:Zombie Marie Curie: Not that I don't deserve it. These two Nobels ain't decorative. But I make a sorry role model if girls just see me over and over as the one token lady scientist.

:Zombie Marie Curie: Lise Meitner figured out that nuclear fission was happening, while her colleague Otto was staring blankly at their data in confusion, and proved Enrico Fermi wrong in the process. Enrico and Otto both got Nobel Prizes. Lise got a National Women's Press Club award.
:Zombie Marie Curie: They finally named an element after her, but not until 60 years later.

:Zombie Marie Curie: Emmy Noether fought past her Victorian-era finishing-school upbringing, pursued mathematics by auditing classes, and, after finally getting a Ph.D, was permitted to teach only as an unpaid lecturer (often under male colleagues' names).
:Ponytail: Was she as good as them?
:Zombie Marie Curie: She revolutionized abstract algebra, filled gaps in relativity, and found what some call the most beautiful, deepest result in theoretical physics.
:Ponytail: Oh.

:Zombie Marie Curie: But you don't become great by trying to be great. You become great by wanting to do something, and then doing it so hard that you become great in the process.

:Zombie Marie Curie: So don't try to be the next me, Noether, or Meitner. Just remember that if you want to do this stuff, you're not alone.
:Ponytail: Thanks.
:Zombie Marie Curie: Also, avoid radium. Turns out it kills you.
:Ponytail: I'll try.

{{comic discussion}}
[[Category:Comics featuring Ponytail]]
[[Category:Zombies]]

894: Progeny

2013-08-14T04:24:16Z

24.142.134.100: 1002

{{comic
| number = 894
| date = May 4, 2011
| title = Progeny
| image = progeny.png
| imagesize =
| titletext = I tell my children 'it's not whether you win or lose, it's how you play the game.' I'm trying to take the edge off their competitive drive to ensure that I can always beat them.
}}

==Explanation==
This comic is a reference to IBM's computer {{w|Watson (computer)|Watson}} that beat humans at {{w|Jeopardy}} (see [[1002: Game AIs]]). The IBM team created a computer that could formulate a response to a Jeopardy-style question. In case you are not familiar, Jeopardy is a game played where the contestants are given the answer to a question, and must devise the question. A question might be "The United States joined this war in 1941" to which the contestant must answer "What is World War II?". When going up against two Jeopardy champions, Watson was able to beat them both.

Megan chimes in that we are "pretty awesome at teaching" which is very true. Humans are the best (on this planet) at teaching other things to do a set of tasks. We train dogs, cats, lizards, birds, other people, and now we are getting quite good at getting a computer, a simple machine completely of our own design, to mimic our own thought patterns and make decisions similar to what we would make.

The title text makes fun of teaching our children values by suggesting we are just trying to hold on to our ability to beat them in something.

==Transcript==
:[Cueball sits at a computer; Megan stands behind him.]
:Cueball: Wow — researchers taught a computer to beat the world's best humans at yet ''ANOTHER'' task. Does our species have ''ANYTHING'' left to be proud of?
:Megan: Well, it sounds like we're pretty awesome at teaching.
:Cueball: Huh? What good is ''THAT''?

{{comic discussion}}
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Megan]]

893: 65 Years

2013-08-14T04:20:10Z

24.142.134.100: 493 and the blag

{{comic
| number = 893
| date = May 2, 2011
| title = 65 Years
| image = 65 years.png
| titletext = The universe is probably littered with the one-planet graves of cultures which made the sensible economic decision that there's no good reason to go into space--each discovered, studied, and remembered by the ones who made the irrational decision.
}}

==Explanation==
In this comic, over 65 years, Randall is projecting the number of living humans who have walked on another world, counting the Moon as a 'world'. He is using {{w|actuarial table}}s or life tables which shows for each age the probability that a certain person will be alive by their next birthday. Although not named, the graph refers to the 12 {{w|List of Apollo astronauts#Apollo astronauts who walked on the Moon|Apollo astronauts}} who landed on the Moon between 1969 and 1972.

This comic assumes that no one else is going to walk on another world going forward into the future which, as is mentioned in the image text, is a terrible idea for the future of the human race. If the human race only exists on one planet — one disaster can destroy the whole race. However, if humans extend their society to other planets, they lessen the risk of complete extinction.

The theme of actuarial projections was explored earlier in [[493: Actuarial]]; [[Randall]]'s script for both was given in [http://blog.xkcd.com/2012/07/12/a-morbid-python-script/ the blag].

==Transcript==
:[A graph titled 'Number of Living Humans Who Have Walked on Another World' — its y-axis is numbered 5, 10, 15; its x-axis increments every ten years from 1960–2040. The line of the graph has a bracket above it that says '65 Years', starting at 1969, ending in 2034.

:The line starts at 1969 and increases steeply to 12 by 1972. It then plateaus until 1991, then declines in three steps to 9 by 1999, and then plateaus again.

:From 2011–2035, which is labeled 'Projected Actuarial Tables', the line branches into three and begins to decline more steeply to zero. The first is labeled '5th {{w|percentile}}' and the third is labeled '95th percentile'; the middle is presumably for the 50th percentile. The area between the lines is shaded. The lines reach zero between about 2022 and 2034, indicating that there is less than a 5% chance that anyone in the group will be alive after that ... unless new people are added.]

{{comic discussion}}
[[Category:Charts]]
[[Category:Math]]

883: Pain Rating

2013-08-14T04:04:15Z

24.142.134.100: 2 -> 1

{{comic
| number = 883
| date = April 8, 2011
| title = Pain Rating
| image = pain rating.png
| titletext = If it were a two or above I wouldn't be able to answer because it would mean a pause in the screaming.
}}

==Explanation==
In medical examinations, a doctor will sometimes ask the patient to {{w|Pain scale|assess their pain}}, to give the doctor a rough idea of the patient's condition. In the comic, Cueball is asked to compare the pain in his arm with the worst pain that he can imagine; the thought of that pain reduces him to a huddled ball.

The title text further emphasizes that idea: if the pain was higher than a 1 on his pain scale, it would already be so high that he would be reduced to uncontrollable screaming.

==Transcript==
:[Ponytail is carrying a clipboard and consulting with Cueball, who's sitting on a high medical table.]
:Ponytail: Any pain?
:Cueball: My arm really hurts.

:[Megan is standing behind Ponytail, as the panel widens.]
:Ponytail: How would you rate the pain, from one to ten, where ten is the worst pain you can imagine?

:[The patient sits on the table.]
:Patient: The worst pain I can imagine?

:[Cueball ponders this, raising a thoughtful hand to his jaw.]

:[Cueball appears to be shocked.]

:[Cueball is huddled up on the table.]
:Cueball: One.
:Ponytail: ... What the hell is wrong with his imagination?
:Megan: It's not a normal place.

{{comic discussion}}
[[Category:Comics featuring Ponytail]]
[[Category:Comics featuring Megan]]
[[Category:Comics featuring Cueball]]

881: Probability

2013-08-14T04:03:13Z

24.142.134.100: fix misunderstanding

{{comic
| number = 881
| date = April 4, 2011
| title = Probability
| image = probability.png
| titletext = My normal approach is useless here, too.
}}

==Explanation==
As the title text says, [[55|my normal approach is useless here]].

[[Cueball]] and [[Megan]] are sitting on a hospital bed reading a piece of paper, with the statistics for {{w|breast cancer}} survival. It looks like Megan has just been diagnosed with breast cancer. The dotted line represents the survival rate distribution: 81% are alive at 5 years, while 77% survive to 10 years.

[[Randall]] posted [http://blog.xkcd.com/2011/06/30/family-illness/ this] blog post two months after posting this strip explaining the cancer strips.

==Transcript==
:[A plot of years vs. percent, with a solid and a dashed line. The solid line starts at 100%, and drops constantly. The dashed line starts around 85%, rises to 95% after 5 years, then drops.]

:[A simple table.]
:5 years 81%
:10 years 77%

:[Two people are sitting on a bench, next to an IV drip hanging from a rack. One is holding a paper.]
:Cueball: You know, probability used to be my favorite branch of math
:Cueball: Because it had so many real-life applications.

:[They embrace, faces together.]

{{comic discussion}}
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Megan]]
[[Category:Romance]]
[[Category:Cancer]]
[[Category:Charts]]
[[Category:Math]]
[[Category:Statistics]]

1047: Approximations

2013-08-14T03:18:36Z

24.142.134.100: /* Transcript */ link ries

{{comic
| number = 1047
| date = April 25, 2012
| title = Approximations
| image = approximations.png
| titletext = Two tips: 1) 8675309 is not just prime, it's a twin prime, and 2) if you ever find yourself raising log(anything)^e or taking the pi-th root of anything, set down the marker and back away from the whiteboard; something has gone horribly wrong.
}}

==Explanation==
This comic lists some approximations for numbers, most of them mathematical and physical constants. All them work astonishingly well. There are reoccurring math jokes along the lines of, “3/5 + π/(7 – π) – √2 = 0, but your calculator is probably not good enough to compute this correctly”, which are mainly used to troll geeks. Those interested in number theory may easily compute that sqrt(2) is not even algebraic in the quotient field of Z[pi], which disproves the equality.

Furthermore, there are some useful approximations (which were even more useful in times before calculators) such as “pi is approximately equal to 22/7”.

[[Randall]] makes fun of both of these, using rather strange approximations (honestly: you may handle 22/7, but who can calculate in a sensible way with 99^8, let alone 30^(pi^e)?) to calculate some constants that are easy enough to handle in the decimal system, and stating such “slightly wrong” trick equations, one of which ''is'' actually correct (which may astonish only those who are not familiar with cosines).

There are a few cultural references in this comic:

* 998 and 698 are sexual references.
* “Rent Method” refers to the song “Seasons of Love” from the musical “{{w|Rent (musical)|Rent}}.” The song asks, “How do you measure a year?” One line says “525,600 minutes” while most of the rest of the song suggests the best way to measure a year is moments shared with a loved one.
* (202) 456-1415 was (at least during the Bush administration) the phone number for the White House switchboard. Randall's formula gives approximately 0.2024561415.
* Jenny's constant comes from Tommy Tutone's tune {{w|867-5309/Jenny}}. Randall's formula gives approximately 867.530901981685.
* {{w|42 (number)|42}} is, according to Douglas Adams' ''The Hitchhiker's Guide to the Galaxy'', the Answer to Life, the Universe, and Everything.

And here are some of the mathematical and physical ones, with Wikipedia links.

* Informally, the {{w|Planck constant}} is the smallest action possible in quantum mechanics.
* The {{w|fine structure constant}} indicates the strength of electromagnetism. It is unitless and around 0.007297, close to 1/137. At one point it was believed to be exactly the reciprocal of 137, and many people have tried to find a simple formula explaining this (with a pinch of {{w|numerology}} thrown in at times).
* In {{w|mathematics}}, the {{w|Euler-Mascheroni constant}} (Euler gamma constant) is a mysterious number describing the relationship between the {{w|harmonic series}} and the {{w|natural logarithm}}.
* The {{w|gravitational constant}} relates to, uh, gravity.
* The {{w|gas constant}} relates energy to temperature in physics.
* ϕ is the {{w|golden ratio}}, or (1 + √5)/2. It has many interesting geometrical properties.
* The ruby laser wavelength varies because “ruby” is not clearly defined.
* The {{w|Earth radios#mean radii|mean earth radius}} varies because there is not one single way to make a sphere out of the earth. Randall's value lies within the actual variation of Earth's radius.

The correct equation in the "Pro tip - Not all of these are wrong" section is cos(pi/7) + cos(3pi/7) + cos(5pi/7) = 1/2 as [http://math.stackexchange.com/questions/140388/how-can-one-prove-cos-pi-7-cos3-pi-7-cos5-pi-7-1-2 shown here].

The image text gives more or less useful information. {{w|Twin prime}}s have always been a subject of interest, because they are comparatively rare, and because it is not yet known whether there are infinitely many of them.

{{w|Pi}} is a natural constant that arises in describing circles or ellipses. As such, useful as it may be, it really shouldn't occur anywhere in an exponent (unless you deal with complex numbers).

Same goes for the e-th power: e typically appears in the basis of a power (forming the {{w|exponential function}}), not in the exponent.

==Transcript==
A table of slightly wrong equations and identities useful for approximations and/or trolling teachers. (Found using a mix of trial-and-error, Mathematica, and Robert Munafo's [http://mrob.com/pub/ries/ ries].) All units are SI MKS unless otherwise noted.

*Relation: One light year(m) ~= 99^8
Accurate to within: one part in 40

*Relation: Earth Surface(m^2) ~= 69^8
Accurate to within: one part in 130

*Relation: Ocean's volume(m^3) ~= 9^19
Accurate to within: one part in 70

*Relation: Seconds in a year ~= 75^4
Accurate to within: one part in 400

*Relation: Seconds in a year (rent method) ~= 525,600 x 60
Accurate to within: one part in 1400

*Relation: Age of the universe (seconds) ~= 15^15
Accurate to within: one part in 70

*Relation: Planck's constant ~= 1/(30^pi^e)
Accurate to within: one part in 110

*Relation: Fine structure constant ~= 1/140
Accurate to within: [I've had enough of this 137 crap]

*Relation: Fundamental charge ~= 3/(14 * pi^pi^pi)
Accurate to within: one part in 500

*Relation: White House Switchboard ~= 1/(e^((1 + 8^(1/(e-1)))^(1/pi)))

*Relation: Jenny's Constant ~= (7^(e/1 - 1/e) - 9) * pi^2

----
Intermission: World Population Estimate which should stay current for a decade or two:

Take the last two digits of the current year

Example: 20[14]

Subtract the number of leap years since hurricane Katrina

Example:14 (minus 2008 and 2012) is 12

Add a decimal point

Example: 1.2

Add 6

Example: 6 + 1.2

7.2 ~= World population in billions.

Version for US population:

Example: 20[14]

Subtract 10

Example: 4

Multiply by 3

Example: 12

Add 10

Example: 3[22] million
----

*Relation: Electron rest energy ~= e/7^16 Joules
Accurate to within: one part in 1000

*Relation: Light-year(miles) ~= 2^(42.42)
Accurate to within: one part in 1000

*Relation: sin(60 degrees) = (3^(1/2))/2 ~= e/pi
Accurate to within: one part in 1000

*Relation: 3^(1/2) ~= 2e/pi
Accurate to within: one part in 1000

*Relation: gamma(Euler's gamma constant) ~= 1/(3^(1/2))
Accurate to within: One part in 4000

*Relation: Feet in a meter ~= 5/(pi^(1/e))
Accurate to within: one part in 4000

*Relation: 5^(1/2) ~= 2/e + 3/2
Accurate to within: one part in 7000

*Relation: Avogadro's number ~= 69^pi^(5^(1/2))
Accurate to within: one part in 25,000

*Relation: Gravitational constant G ~= 1/(e^((pi - 1)^(pi + 1)))
Accurate to within: one part in 25,000

*Relation: R(gas constant) ~= (e+1) * (5^(1/2))
Accurate to within: one part in 50,000

*Relation: Proton-electron mass ratio ~= 6*pi^5
Accurate to within: one part in 50,000

*Relation: Liters in a gallon ~= 3 + pi/4
Accurate to within: one part in 500,000

*Relation: g ~= 6 + ln(45)
Accurate to within: one part in 750,000

*Relation: Proton-electron mass ratio ~= (e^8 - 10)/phi
Accurate to within: one part in 5,000,000

*Relation: Ruby laser wavelength ~= 1/(1200^2)
Accurate to within: [within actual variation]

*Relation: Mean Earth Radius ~= (5^8)*6e
Accurate to within: [within actual variation]

----
Protip - not all of these are wrong:

*2^(1/2) ~= 3/5 + pi/(7-pi)

*cos(pi/7) + cos(3pi/7) + cos(5pi/7) ~= 1/2

*gamma(Euler's gamma constant) ~= e/3^4 + e/5

*5^(1/2) ~= (13 + 4pi)/(24 - 4pi)

*sigma(1/n^n) ~= ln(3)^e

{{comic discussion}}
[[Category:Charts]]
[[Category:Math]]
[[Category:Physics]]
[[Category:Protip]]

Talk:1002: Game AIs

2013-08-14T01:40:45Z

24.142.134.100: Watson

Mornington Crescent would be impossible for a computer to play, let alone win... {{unsigned|188.29.119.251}}
It is unclear which side of the line jeopard fall upon. Why so close to the line I wonder. [[User:DruidDriver|DruidDriver]] ([[User talk:DruidDriver|talk]]) 01:04, 16 January 2013 (UTC)

: Because of {{w|Watson (computer)}}. (Anon) 13 August 2013

Could the "CounterStrike" be referring instead to the [http://en.wikipedia.org/wiki/Counter-Strike computer game] which can have computer-controlled players? --[[Special:Contributions/131.187.75.20|131.187.75.20]] 15:49, 29 April 2013 (UTC)

Talk:734: Outbreak

2013-08-14T01:17:46Z

24.142.134.100: correction/annotation

A romantic comedy in which the couple tries to hide evidence of the battered corpse while making out. Would pay to watch. '''[[User:Davidy22|Davidy22]]'''[[User talk:Davidy22|<tt>[talk]</tt>]] 13:22, 18 February 2013 (UTC)

cueball and megan? the text clearly name the characters as ryan and laura [[Special:Contributions/189.135.111.140|189.135.111.140]] 18:48, 17 April 2013 (UTC)

:# Cueball and Megan are acting in a movie.
:# In the transcript, Randall specifically names them as Cueball and Megan. :-) [[User:Saibot84|Saibot84]] ([[User talk:Saibot84|talk]]) 02:38, 18 May 2013 (UTC)

::: Note that "Cueball" and "Megan" are merely the ''Explain xkcd'' names. [http://xkcd.com/734/info.0.json The official transcript] refers to them only as "Man" and "Woman". (Anon) 13 August 2013

I love how Ryan is covering his face when he holds the door open. [[Special:Contributions/76.106.251.87|76.106.251.87]] 23:27, 20 April 2013 (UTC)
:I saw it as trying to plug his ear. Shotguns are loud, especially indoors.[[User:Tryc|Tryc]] ([[User talk:Tryc|talk]]) 14:24, 8 July 2013 (UTC)

718: The Flake Equation

2013-08-13T23:46:17Z

24.142.134.100: 384

{{comic
| number = 718
| date = March 24, 2010
| title = The Flake Equation
| image = the flake equation.png
| titletext = Statistics suggest that there should be tons of alien encounter stories, and in practice there are tons of alien encounter stories. This is known as Fermi's Lack-of-a-Paradox.
}}

==Explanation==
{{incomplete}}
The Flake equation is a parody of the {{w|Drake equation}}, which estimates the number of detectable extraterrestrial civilizations in the galaxy.

The title text refers to Fermi's Lack-of-a-Paradox as a parody of the {{w|Fermi paradox}}: the contradiction between the high estimated probability of extraterrestrial civilization and humanity's lack of evidence for such civilizations.

Another comic parodying this equation is [[384: The Drake Equation]].

==Transcript==
:

{{comic discussion}}
[[Category:Math]]

712: Single Ladies

2013-08-13T23:42:56Z

24.142.134.100: correction regarding elves, better explanation of plot

{{comic
| number = 712
| date = March 10, 2010
| title = Single Ladies
| image = single_ladies.png
| titletext = Using a ring to bind someone you covet into your dark and twisted world? Wow, just got the subtext there. Also, the apparently eager Beyoncé would've made one badass Nazgûl.
}}

==Explanation==
The character in armor is {{w|Sauron}}, the main villain in ''{{w|The Lord of the Rings}}'' trilogy. In the backstory, he takes control of Middle-earth by giving several rings as "gifts" to the great kings of dwarves, men, and possibly elves. However, he also forged a master ring, the {{w|One Ring}}, to control the gifted rings and ultimately power over the kings. However, the elves were not deceived by his plan and Sauron is eventually defeated by a human who cuts off his ring finger. The books tell the story of a small group of adventurers who rediscover the lost Ring and attempt to destroy it, as Sauron's army gathers its forces to attempt to reclaim the Ring for their master.

{{w|Gil-galad}} is a high Elven-king, and {{w|Galadriel}} is an Elf of royal blood who serves as a matriarch of sorts to the remnants of the Elven race. Lindon is a location on the westernmost side of the continent, serving as the final transition point for Elves passing on to the Undying lands. Sauron refers to an actual event in the first panel, when he tried to gain control of Lindon through deceit; Galadriel and Gil-galad saw through his disguise and cast him out.

The song playing in the background is "All the Single Ladies" by Beyoncé, which includes the line "If you liked it then you should have put a ring on it," referring to ''wedding'' rings. This, evidently, is what inspired Sauron to devise his plan to control others through the gift of rings.

The title text refers to an often-suggested fan theory that the One Ring ''is'' actually meant to be symbolic of marriage. The {{w|Nazgûl}}, also known as ringwraiths, are a band of nine servants to Sauron who constantly seek out the Ring for him. As a bit of trivia, Randall used the wrong "û" character when editing the title text; the character he used was U+0217 LATIN SMALL LETTER U WITH INVERTED BREVE, but the correct character is U+00FB LATIN SMALL LETTER U WITH CIRCUMFLEX. They look very similar at standard font sizes, but the inverted breve is curved, while the circumflex is pointed.

==Transcript==
:[Beret Guy is talking to Sauron; Sauron is wearing his trademark helmet, but his head is downcast. Music plays in the background.]
:''Music: All the single ladies, All the single ladies''
:Beret Guy: Hey Sauron, why so glum?
:Sauron: Gil-galad saw through me and threw me out of Lindon. Galadriel as well. I'll never rule ''anyone'' at this rate.

:''Music: All the single ladies, All the single ladies''
:Sauron: Eru created such beautiful creatures - Elves and men and dwarves - and all I've got are these stupid orcs.

:''Music: 'Cause if you liked it then you should have put a ring on it''
:Sauron: I mean, I -

:[Sauron is suddenly quiet]
:''Music: If you liked it then you should have put a ring on it''

{{comic discussion}}
[[Category:Romance]]
[[Category:Comics featuring Beret Guy]]
[[Category:LOTR]]

677: Asshole

2013-08-13T23:09:19Z

24.142.134.100: 437

{{comic
| number =677
| date =December 18, 2009
| title =Asshole
| image =asshole.png
| titletext =[Shortly thereafter, at a nearby bakery] ::CRASH:: ::RUMBLE:: ::VRRRRRR:: "... I don't know, officer. It just scooped up an entire rack of scones and drove away!"
}}

==Explanation==
SUVs are incredibly large personal vehicles with a massive amount of cargo space, and notorious gas-guzzlers. The stereotype is that SUV owners drive such massive cars because they're compensating for something. Upon hearing [[Cueball]] call him an asshole for driving an SUV, [[Beret Guy]], hoping to win peoples' approval, trades his SUV in at the dealership for a hybrid subcompact.

Hybrid sedans are vehicles that can be powered by both gasoline and electricity - that is, by plugging them into a wall socket between uses. The stereotype is that people drive them so that they can feel superior to others, and that's exactly what [[Megan]] says when Beret Guy drives past them a second time.

Annoyed, Beret Guy trades in his car a second time, this time to get a massive construction vehicle and smack them with it. In the title text, he also uses it to get himself a whole bunch of scones, one of Beret Guy's trademarks.

[[437: SUV]] is another take on this comic.

==Transcript==
:[A couple watches Beret Guy drive by in an SUV.]
:Cueball: Look at that asshole in his SUV, thinking he's so badass while he guzzles gas driving around suburbia.
:Beret Guy: Oh no! Am I an asshole? I hope not.

:[Beret Guy trades in his keys at the dealership.]

:[Now he is driving by in a hybrid sedan.]
:Megan: Look at that smug asshole thinking he's better than us because he drives a hybrid.
:Beret Guy: ...

:[He trades in his keys again.]

:[The couple is standing.]
:Off-panel: ''RUMBLE''

:[Beret Guy drives a backhoe in and smacks the couple out of the panel with the digger.]

:[He drives off, whistling.]

{{comic discussion}}
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Megan]]
[[Category:Comics featuring Beret Guy]]

676: Abstraction

2013-08-13T23:09:13Z

24.142.134.100: 484

{{comic
| number = 676
| date = December 16, 2009
| title = Abstraction
| image = abstraction.png
| titletext = If I'm such a god, why isn't Maru *my* cat?
}}

==Explanation==
The comics points out the large number of levels of abstraction working together at any given time in today's computers.

Programs on current computers do not run "directly on hardware". Instead, the hardware (in this case, a {{w|Central processing unit|processor}} of the {{w|x86-64}} architecture) is controlled by the {{w|operating system}} {{w|Kernel (computing)|kernel}} (in this specific case, {{w|XNU}} is the kernel used in Apple-branded devices). Many operating systems offer a standardized {{w|Interface (computing)|interface}} called {{w|POSIX}}, which wraps the services offered by the different operating systems so that applications do not need to cope with the differences between the operating systems. {{w|Darwin (operating system)|Darwin}} is the name of the core set of components on which the Apple's {{w|OS X}} operating system runs. And using this operating system, the user runs the {{w|Firefox}} web browser. However, the browser itself contains further abstraction layers: {{w|Gecko (layout engine)|Gecko}} is the engine handling the display of web pages on the screen, but in this case, it only allows a separate software, {{w|Adobe Flash Player}}, to render a video requested by the user.

And all of this work is, in this case, done only because the user wanted to watch a funny cat video on the Internet; which makes the user feel like he is a god.

The title text refers to {{w|Maru (cat)|Maru the cat}}, a cat who became very popular on YouTube. Cueball questions his god-like capabilities by wondering why can't he own Maru.

[[484: Flash Games]] offers another take on the highly abstracted layers of a computer.

==Transcript==
:[Cueball is sitting at a computer.]
:An x64 processor is screaming along at billions of cycles per second to run the XNU kernel, which is frantically working through all the POSIX-specified abstraction to create the Darwin system underlying OS X, which in turn is straining itself to run Firefox and its Gecko renderer, which creates a Flash object which renders dozens of video frames every second

:because I wanted to see a cat jump into a box and fall over.

:I am a god.

{{comic discussion}}
[[Category:Comics featuring Cueball]]
[[Category:Computers]]

674: Natural Parenting

2013-08-13T23:04:47Z

24.142.134.100: 441

{{comic
| number = 674
| date = December 11, 2009
| title = Natural Parenting
| image = natural_parenting.png
| imagesize =
| titletext = On one hand, every single one of my ancestors going back billions of years has managed to figure it out. On the other hand, that's the mother of all sampling biases.
}}

== Explanation ==

This comic relates to the anxiety most couples experience after having a child. Some couples employ an approach called natural parenting or {{w|attachment parenting}}. This strategy for child-rearing normally entails providing whole foods and extended nursing but can also include birth without anesthetics, applying reusable cloth diapers, using herbal remedies instead of medicine, and other decisions intended to protect the environment and raise a baby to be physically and mentally healthy. Natural parenting approaches can vary greatly from parent to parent, with some being very extreme and possibly detrimental. Because of the awkwardness and stigma of breastfeeding as well as its traditionalism, attachment parenting can elicit powerful opinions from both its opponents and proponents. Various media and politicians have seized on this hot topic, as well as motherhood in general. Extreme natural parenting methods became the notorious cover story of TIME Magazine in May 2012.

However, the characters in this strip took natural parenting to mean doing "what comes naturally", i.e. having another baby.

[[441: Babies]] is another strip featuring clueless new parents.

===Title text===
One interpretation of the title-text is as note of the sentiments expressed by proponents of natural parenting, stating that traditional or instinctive methods have worked for thousands of years. It is also possible that the narrator means that parenting can't be too hard because historically everyone must have figured it out. Randall jokes that this is the "mother" of all sampling biases because his ancestors represent only the (possibly small) fraction who survived the instinctive or easily learned methods of parenthood, instead of the entire sample of people attempting to raise children.

==Transcript==

:[A man and woman are standing with a baby in between them.]
:Man: Oh man, we made a baby.
:Woman: Don't panic. Don't panic.
:Baby: Baby!

:Man: Parenting can't be that hard. Let's just do what comes naturally.

:[Beat frame]

:Soon:
:[There are now two babies in between them.]
:Woman: Aw, crap.

{{comic discussion}}

[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Megan]]
[[Category:Romance]]

560: Lithium Batteries

2013-08-13T03:56:29Z

24.142.134.100: /* Explanation */ White?

{{comic
| number = 560
| date = March 25, 2009
| title = Lithium Batteries
| image = lithium_batteries.png
| titletext = I'm normally a pretty frugal person, but I still compulsively buy any R/C aircraft that's less than $30. In the last few years, this has become a problem.
}}

==Explanation==
In this comic, Randall muses that his life would have been better if he aged in reverse based on a timeline of the usage of lithium-ion batteries. Presumably, the reason is that each of these uses would come to realization when he most needed it (i.e. a pacemaker when he is old, a phone when he is a rich businessperson, etc.). This comic might be a shout-out to "The Curious Case of Benjamin Button", by F. Scott Fitzgerald or "The Once and Future King" by T. H. White.

==Transcript==
:Timeline of Commercial Uses of Lithium Batteries:
:[The panel has a timeline that goes from Past to Present. The timeline has 4 notches on it.]
:Past
:[the first notch, closest to the past side, has a picture of an old man with a walking stick.]
:Pacemakers
:[The second notch has an image of a man in a car, who is talking on his cell phone.]
:Phones for Rich Business People
:[The third notch, has a teen taking on his cellphone.]
:Phones for Teenagers
:[The forth notch, closest to the present on the timeline, and an image of a toy plane box with $10 written on it.]
:Really cheap r/c planes and helicopters
:Present
:[Below the main panel.]
:Life would be so much better if I was one of those people who aged backward.

{{comic discussion}}

Talk:541: TED Talk

2013-08-13T03:38:18Z

24.142.134.100: category?

It's not the first time Randall gets banned from conventions, see [[153: Cryptography]].
[[User:Xylon|Xylon]] ([[User talk:Xylon|talk]]) 13:10, 9 April 2013 (UTC)

: There are enough of these that it should probably be a category. (Anon) 12 August 2013

Talk:457: Frustration

2013-08-12T04:49:52Z

24.142.134.100: analysis seems off

...or "I can do '''it''' in under a minute" is taken as a euphamism for speedy performance ''after'' the bra puzzle is solved (or ignored). Which doesn't always impress a partner. I've heard. --[[Special:Contributions/178.107.249.215|178.107.249.215]] 22:20, 13 June 2013 (UTC)

The previous description ended with:

:The second person replies that they've noticed, perhaps sarcastically suggesting that the first person is far more interested in solving a Rubik's cube than actually removing the bra and... everything that follows.

While a subtle perspective, it glosses over the obvious joke about the Rubik's solver's speedy performance in the sack. --[[User:MisterSpike|MisterSpike]] ([[User talk:MisterSpike|talk]]) 18:39, 26 June 2013 (UTC)

I think this analysis is off. I think is should not be interpreted as an actual bra with a cube fastener, but rather comparing the difficulty of removing a bra with solving a cube. He says he can get it but opens himself up to the obvious joke by so proclaiming. -anon

453: Upcoming Hurricanes

2013-08-12T04:43:09Z

24.142.134.100: Wikipedia link

{{comic
| number = 453
| date = July 23, 2008
| title = Upcoming Hurricanes
| image = upcoming_hurricanes.png
| imagesize =
| titletext = I'd like to see more damage assessments for hurricanes hitting New York and flooding Manhattan -- something like the 1938 Long Island Express, but aimed a bit more to the west. It's just a matter of time.
}}

==Explanation==
It must be hurricane season! This comic gives some ideas on upcoming hurricane paths. Lets look at each path.

Hurricane Illinois-Has-It-Too-Easy: They really do. This smart hurricane, while actually impossible, comes from Canada to strike little old Chicago before heading back to Canada. Interestingly, though it did not affect the Chicago area or correspond with the path displayed in the comic, roughly one year later a superderecho, a storm resembling a hurricane or tropical storm in movement and form, struck central and South Illinois, in addition to much of Missouri and Kansas: {{w|May 2009 Southern Midwest derecho}}.

Hurricane Where-The-Hell-Is-Bermuda: Nice little irony here, normally people get lost once they get to the triangle and never come back. This poor hurricane can't even get there to get lost.

Hurricane Screw-It-Let's-Just-Trash-Florida-Again: Why you would want to live in Florida during hurricane season is beyond me. Sticking out from the rest of the US, Florida is in a nice spot to get hurricanes from the East, South, and West. And with the state not being very high or wide, it is common for a hurricane to run over Florida, lose some strength, then rebuild in the Gulf of Mexico, only to do a U-turn and strike again.

Hurricane Freud: You just need to know that {{w|Sigmund Freud}} had a thing about sex, and let's just leave it at that.

Hurricane Red and Blue: Playing a game of Light Cycles from {{w|Tron}}, Hurricane Blue lost — it crashed into the lightwall of Hurricane Red.

Hurricane Cos(x): Its path resembles a sine wave, though it's not actually centered on the equator, ranging from about 5.5° to 9.5° north latitude.

The title text refers to a 1938 Category 5 Hurricane that caused $41.1 billion in damage in current money. Had it been further west it could have caused more damage as the right side of a hurricane is stronger and more destructive than the left side as the winds on the right side push water inland. Four years after this cartoon was published, {{w|Hurricane Sandy}} did strike the New York–New Jersey area, causing an estimated $74 billion in damages.

==Transcript==
:[An unlabeled map shows the region roughly between central Canada and northern Brazil. Dotted lines indicating hurricane paths cover the map, all red except where noted.
:Hurricane Illinois-Has-It-Too-Easy comes from somewhere to the northwest, goes through Illinois, and then back to the northwest.
:Hurricane Where-the-Hell-Is-Bermuda enters from the east side of the map, wanders around the Atlantic in a scribble, goes north for a while, and then peters out.
:Hurricane Screw-It-Let's-Just-Trash-Florida-Again comes from the east, starts to curve to the north, and then turns sharply to head straight for Florida and zigzag through it.
:Hurricane Freud starts in the Gulf of Mexico, draws a set of balls to Florida's cock, and then comes on land and stops.
:Hurricane Red and Hurricane Blue (which is a blue line) are playing a game of Tron, zipping in straight lines and right angles around Haiti, Jamaica, and Cuba. Red successfully cuts off Blue and then dies shortly thereafter.
:Hurricane cos(x) forms a graph of cos(x) along the bottom edge of the map.]

{{comic discussion}}
[[Category:Hurricanes]]
[[Category:Comics with color]]

452: Mission

2013-08-12T04:38:50Z

24.142.134.100: link 434

{{comic
| number = 452
| date = July 21, 2008
| title = Mission
| image = mission.png
| titletext = Don't you know? The chances of a random object being a scone are about one in six.
| imagesize =
}}

==Explanation==
[[Cueball]] and [[Beret Guy]] are on a mission, intending to destroy whatever machine they are in. Except that [[Beret Guy]] tends to be a bit surreal and brought a bag for holding pastries instead of explosive charges.

This is not the first time he's mistaken a mission for a trip to a bakery; see [[434: xkcd Goes to the Airport]].

==Transcript==
:[Beret Guy and Cueball are rappelling down separate ropes into the interior workings of a large machine]
:Cueball: Okay, we're in the belly of the machine. You got the charges?
:Beret Guy (with beret): The what?

:[The two are standing next to some large pieces of machinery]
:Cueball [gesturing]: The explosive charges!
:Beret Guy [pulling out a bag]: I just brought this bag for pastries.
:Cueball: The hell? We're on a mission here!

:Beret Guy [looking around]: This isn't a bakery?
:Cueball [head in hand]: Oh, Christ, not this shit again.

:Beret Guy [crouching by some lug nuts lying on a piece of machinery]: What about these scones?
:Cueball: Those are lug nuts.
:Beret Guy [stuffing them in his mouth]: ...Maybe SOME of them aren't. ''crunch'' Ow! ''crunch''

{{Comic discussion}}
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Beret Guy]]

398: Tap That Ass

2013-08-12T03:33:36Z

24.142.134.100: grammar

{{comic
| number = 398
| date = March 19, 2008
| title = Tap That Ass
| image = tap_that_ass.png
| titletext = Hey, when you're done draining the syrup, just leave the hole, okay?
}}

==Explanation==
This comic uses verbal irony to exploit the application of double meanings. The phrase "tap that ass" is a colloquialism for "to have intercourse with that person" and is most likely how the reader expects the phrase to be used. However, throughout the comic, this is not the case.

In the first panel, it is possible that [[Cueball]] is using "tap that ass" sexually. However, it is more likely that he is using "tap" to mean "pick" or "choose", in which case he would be willing to be chosen to be the committee chair. "That ass" refers to one of the individuals in the meeting room to exchange positions with.

In the second panel, "tap" is referring to wiretapping. It is possible that it is being referenced in a sexual manner, but makes much less sense that the wiretapping explanation. "That ass" refers to the person on the telephone.

In the third panel, "tap" is referring to extracting sap from trees. A sexual connotation would make no sense in this context. "That ass" refers to the maple tree.

In the final panel, [[Cueball]] attempts to take the scenario from the third frame and interpret it sexually, showing how absurd it would be to assume "tap that ass" always refers to having intercourse.

[[Cueball]] is not the same individual throughout the frames of this particular comic.

==Transcript==
:[Cueball in a hallway looking in on a board meeting.]
:Cueball: I'd tap that ass
:Cueball: To be the new committee chair.
:[Cueball wearing headphones with a briefcase and a laptop. Another man on a telephone.]
:Cueball: I'd tap that ass
:Cueball: Without a warrant.
:[Cueball with his hand on his chin, looking at a tree.]
:Cueball: I'd tap that ass
:Cueball: And extract delicious maple syrup.
:[Cueball standing in a blank frame.]
:Cueball: I'd have sex
:Cueball: With that tree.

{{comic discussion}}
[[Category:Comics featuring Cueball]]
[[Category:Language]]

388: Fuck Grapefruit

2013-08-12T03:13:44Z

24.142.134.100: /* Explanation */ "most controversial"

{{comic
| number = 388
| date = February 25, 2008
| title = Fuck Grapefruit
| image = fuck_grapefruit.png
| titletext = Coconuts are so far down to the left they couldn't be fit on the chart. Ever spent half an hour trying to open a coconut with a rock? Fuck coconuts.
}}

==Explanation==
This comic consists in a chart where [[Randall]] plotted fruits according to two criteria: ease/difficulty to eat, and tastiness. For instance, pineapples are deemed fairly tasty but very difficult to eat, whereas (seeded) grapes are very tasty and rather easy, and logically seedless grapes are equally tasty while being far more easy at the same time.

Obviously being easy to eat is preferable to being difficult, and being tasty is preferable to being untasty, so the "best" fruits (regarding these two aspects only) are in the top-right corner, and the worst in the bottom-left one; additionally, in the top-left corner are the "difficult-but-worthy" fruits, and in the bottom-right one, the "not-so-tasty-but-easy-anyway" ones.

According to the resulting chart, grapefruit is the worst fruit (from the ones listed at least): eating one of them is like spending too much of one's time and energy without much reward. Therefore, fuck grapefruit.

The title text adds a joke about coconuts, concerning the fact that they are incredibly more difficult to eat (especially to open) than the usual mainstream fruits such as the ones plotted here. Therefore, 1/ coconuts could not fit on the chart, they are too much on the left (or if they had been put in the chart, they would have relegated all the other fruits on the far right, all equally "easy" in comparison to coconuts and therefore indiscernible between each other on this criterion); and 2/ fuck coconuts as well.

According to the blag, [http://blog.xkcd.com/2008/02/25/fruit-opinions/ this was the most controversial comic written to this point], "beating out comics about cunnilingus, the Obama endorsement, and my making 4chan tiny on the map of the internet".

==Transcript==
:[A X Y plot of fruit, showing tastiness on the vertical axis and difficulty-of-consumption on the horizontal axis. The Y-axis goes from "tasty" at the top, to "untasty" at the bottom. The X-axis goes from "easy" on the right to "difficult" on the left.]
:{The following listing for each fruit assumes that the extremes of each axis are 100%. Note that this does not agree with the alt text, but whatever.}
:[Seedless grapes: 75% tasty, 100% easy
:Peaches: 100% tasty, 75% easy
:Strawberries: 80% tasty, 75% easy
:Blueberries: 70% tasty, 90% easy
:Pears: 30% tasty, 75% easy
:Green apples: 25% tasty, 80% easy
:Seeded grapes: 75% tasty, 10% easy
:Cherries: 30% tasty, 40% easy
:Plums: 10% tasty, 60% easy
:Red apples: 5% untasty, 80% easy
:Bananas: 10% untasty, 10% easy
:Watermelons: 10% tasty, 10% difficult
:Tomatoes: 60% untasty, 20% easy
:Pineapples: 50% tasty, 100% difficult
:Oranges: 40% untasty, 50% difficult
:Lemons: 100% untasty, 10% difficult
:Pomegranates: 10% untasty, 90% difficult
:Grapefruit: 90% untasty, 80% difficult]

{{comic discussion}}
[[Category:Charts]]
[[Category:Comics with color]]

346: Diet Coke+Mentos

2013-08-11T17:58:44Z

24.142.134.100: 1053 reference

{{comic
| number = 346
| date = November 19, 2007
| title = Diet Coke+Mentos
| image = diet_coke_mentos.png
| titletext = The cola+Mentos trick is up there with corn starch+water (vibrating platter optional) in scientific coolness out of common kitchen supplies.
}}

==Explanation==
This strip exploits irony using the popular meme of mixing Mentos into a bottle of soda. There was a period of time when a large portion of videos depicting this phenomena floated around the Internet, but the novelty starts to wear off once you've seen a bunch of these. So, you expect the character in the strip to show off the incredible phenomena to his friend, because it's "the coolest thing", but it turns out instead of fizzling Diet Coke everywhere, the friend's father magically shows up (presumably from the dead or from abandonment). That would surely be "cooler" than just some soda reacting with sugars. This hints that the author might consider the fad unworthy of too much excitement, and that he considers people's liberal use of the phrase "the coolest thing" unjustified.

An alternate take appears in [[1053|1053: Ten Thousand]].

==Transcript==
:Friend: This is the coolest thing. You just drop the mentos in the Diet Coke...
:Cueball: Uh huh.
:Friend: Give it a moment...
:[Diet Coke starts to fizzle.]
:[Someone teleports into frame in a magic puff.]
:Cueball: D-Dad?
:Dad: I'm back, son. We can be a family again.

{{comic discussion}}
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Hairy]]