explain xkcd - User contributions [en]

Talk:2301: Turtle Sandwich Standard Model

2020-05-02T00:48:03Z

162.158.74.57:

This is the first time I have had a chance to see the comic early enough to make a meaningful contribution to the explanation, but this time I have no idea whatsoever what the comic is about! [[User:Moosenonny10|Moosenonny10]] ([[User talk:Moosenonny10|talk]]) 20:32, 1 May 2020 (UTC)

Looks like it is referencing the standard model of elementary particles. The title text mentions four of the quarks(top,bottom,charm,strange) [[Special:Contributions/162.158.106.150|162.158.106.150]] 20:38, 1 May 2020 (UTC)

Disagree with DgbrtBOT that this is primarily to do with genetics. I agree that it's about the standard model. Up, down, charmed and strange. It may 'because I'm dumb', but even I'm not that dumb.
:I agree that this is not about genetics. The usual Mendelian diagram has the same traits in both dimensions. Maybe he didn't make the particle physics connection because that has more than 4 boxes. [[User:Barmar|Barmar]] ([[User talk:Barmar|talk]]) 21:52, 1 May 2020 (UTC)
:Agree with Barmar: This is not at all about genetics, but only about the particles standard model. Hence the name given by Randal, hence the dimensions not fitting Mendel, hence the lab reference and hence the biological absurd combinations. It does not fit genetics at all, but it perfectly fits a basic assumption of the standard particle modell: That every combination does exist. Labs all over the world have spend decades trying find/prove the existance of a particle predicted by lining up the dimensions of the particles standard model just as shown here and most seeming just as absurd. [[Special:Contributions/172.68.51.52|172.68.51.52]] 00:06, 2 May 2020 (UTC)

I added a bit about the physics part of it, but it can definitely use more information! [[User:ChunyangD|ChunyangD]] ([[User talk:ChunyangD|talk]]) 20:52, 1 May 2020 (UTC)

Randall missed an obvious physics/turtle joke "turtles all the way down" reference here [[Glenn Strycker]] 4:56pm CDT 1 May 2020

If this really is about genetics, which I question, it seems likely that most people who haven't studied genetics would find the use of genetics jargon to be less than helpful in an explanation.[[User:Darthpoppins|Darthpoppins]] ([[User talk:Darthpoppins|talk]]) 22:46, 1 May 2020 (UTC)

In my opinion, the ExplainXKCD community has been successfully trolled by the contributor of the explanation of this comic, and with humorous effect. The troll consists of an explanation couched entirely in terms used primarily by biologists but generally difficult for others to understand, contrary to this community's practice of trying to simplify. [[Wikipedia:genotype|Genotypes]], [[Wikipedia:phenotype|phenotypes]], [[Wikipedia:Punnett Square|Punnett Squares]], [[Wikipedia:heterozygous|heterozygous]], [[Wikipedia:homozygous|homozygous]], [[WIkipedia:ontogeny|ontogeny]]. That being said, the contributor is certainly correct that the comic is about [[Wikipedia:genetics|genetics]], in that the depicted two-by-two square is immediately suggestive of the visual tool used for predicting the results of cross-breeding experiments. And the comic is certainly also about [[Wikipedia:particle physics|particle physics]], in that the comic title refers to a "Standard Model" and then the title text alludes to particle names used in the [[Wikipedia:standard model|standard model of particle physics]]. So the comic's joke is about the unexpected juxtaposition of genetics with particle physics, and also is about turtle sandwiches which, as drawn, are intrinsically funny anyway. Yes, @Glen, all the way down. JohnB [[Special:Contributions/162.158.75.116|162.158.75.116]] 00:25, 2 May 2020 (UTC)

This looks less like a Punnet Square than it does like one of those political alignment chart memes. Punnet squares use symbols next to each other to designate genotypes, not diagrams of the results. Not to mention that the individual labels along the sides are supposed to be alleles, not separate effing traits! That whole paragraph is completely wrong and should be removed. [[User:GreatWyrmGold|GreatWyrmGold]] ([[User talk:GreatWyrmGold|talk]]) 00:44, 2 May 2020 (UTC)

Isn't this about supersymmetry? The missing pieces are the bosonic partners of the known fermions (matter particles), and the fermionic partners of the known bosons (force particles).... Joel K

Talk:2301: Turtle Sandwich Standard Model

2020-05-02T00:47:20Z

162.158.74.57:

Talk:Disappearing Sunday Update

2019-08-05T02:52:54Z

162.158.74.57: archive.org link

This comic isn't a numbered comic. The ephemeral ghost comic has broken explainxkcd! [[Special:Contributions/162.158.34.64|162.158.34.64]] 22:23, 4 August 2019 (UTC)

Well, it broke the xkcd client I use. (Easy xkcd, Android) Just crashes on start. I hope it will fix itself when the normal one comes out. I also hope that this comic will remain here when it is taken down. [[User:Fghsgh|Fghsgh]] ([[User talk:Fghsgh|talk]]) 22:43, 4 August 2019 (UTC) fghsgh

Previous then Next on xkcd.com 404's... Trivia! [[Special:Contributions/141.101.104.83|141.101.104.83]] 22:59, 4 August 2019 (UTC)

It's not rendering for me on the uni.xkcd.com portal, could anyone else verify? I'm excited in seeing what else this comic will break. [[User:Kirdneh|Kirdneh]] ([[User talk:Kirdneh|talk]]) 23:11, 4 August 2019 (UTC)

I wonder what will happen tomorrow! Oh the antici- pation!
[[Special:Contributions/172.69.68.153|172.69.68.153]] 00:01, 5 August 2019 (UTC) Sam

Others had the same idea I did, this comic has been archived to https://web.archive.org/web/20190805000153/https://xkcd.com/ For posterity(?) [[Special:Contributions/162.158.74.57|162.158.74.57]] 02:52, 5 August 2019 (UTC)

2078: Popper

2018-12-04T02:02:35Z

162.158.74.57: /* Explanation */

{{comic
| number = 2078
| date = November 28, 2018
| title = Popper
| image = popper.png
| titletext = At least, I don't think there's evidence. My claim that there's no evidence hasn't been falsified. At least, not that I know of.
}}

==Explanation==
{{incomplete|There is no evidence that this wasn’t created by a random guy with evil intentions. Please mention here why this explanation isn't complete. Do NOT delete this tag too soon.}}
In this comic, [[Miss Lenhart]] teaches to a class comprising of [[Hairy]], [[Ponytail]], and [[Science Girl]] about {{w|Karl Popper}}. Karl Popper was a philosopher of science who endorsed the idea that science is distinguished from non-science by treating its theories as falsifiable. This means that science does not treat any theory as definitive, because future research could show that it is false.

A not uncommon reading of Popper assumes that instead of proving hypotheses, scientists are disproving hypotheses. This reading leads to technicalities like the ones stated in the comic: Instead of asserting that Popper was indeed born on July 28, 1902, and grew up in Vienna, a scientist can only assert that there is no evidence disproving these facts, which seems counter-intuitive because one cannot disprove the facts of Popper's birthdate and childhood residence.

Note however that falsifiability is often interpreted to mean that there has to be a way to disprove a given statement if it is wrong, or to distinguish between two mutually competing hypotheses; not that a statement is accepted solely due to the lack of evidence to the contrary, e.g. a birth certificate is often used to establish a date of birth and falsifying that date of birth would then mean calling into question the birth certificate's authenticity or accuracy, but without any historical records of the date of birth one would normally not even speculate at all about the precise date of birth. As such reasoning solely on the absence of proof to the contrary would be considered unusual in most contexts.

The humor comes when the comic applies this idea to the life and biographical information of Karl Popper himself. Note that in real life, such a subject would be a matter for ''historical'' proof, not scientific, and would thus fall outside the realm of study Popper was thinking of.

The title text takes this reading a couple of steps further in a kind of meta-analysis. It points out that [[Miss Lenhart]]'s claim of no evidence has not been proven false, and also that we're dealing with only the knowledge of a single individual who may not be aware of evidence that might exist.

Another reading of Popper points out that Popper’s philosophy discarded proofs altogether as a defining feature of science. Thus there is no such thing as definitive evidence in Popper’s notion of science: Even falsifying assertions themselves are seen as falsifiable.

==Transcript==
:[Miss Lenhart is teaching a class of three students; Hairy, Ponytail, and Science Girl, sitting behind their desks.]
:Miss Lenhart: There's no evidence that Karl Popper wasn't born on July 28th, 1902.
:Miss Lenhart: No one has proven that he didn't grow up in Vienna...

{{comic discussion}}

[[Category: Comics featuring Miss Lenhart]]
[[Category: Comics featuring Hairy]]
[[Category: Comics featuring Ponytail]]
[[Category: Comics featuring Science Girl]]
[[Category: Comics featuring real people]]
[[Category: Science]]
[[Category: Philosophy]]

2034: Equations

2018-11-13T22:31:36Z

162.158.74.57: /* Explanation */

{{comic
| number = 2034
| date = August 17, 2018
| title = Equations
| image = equations.png
| titletext = All electromagnetic equations: The same as all fluid dynamics equations, but with the 8 and 23 replaced with the permittivity and permeability of free space, respectively.
}}
==Explanation==
{{incomplete|TODO: some simplified explanations. The title text is bad explained. Do NOT delete this tag too soon.}}

This comic gives a set of equations supposedly from different areas of science in mathematics, physics, and chemistry. To anyone not familiar with the field in question they look pretty similar to what you might find in research papers or on the relevant Wikipedia pages. To someone who knows even a little about the topic, they are clearly very wrong and only seem even worse the more you look at them. In many disciplines, the mathematical description of a large area is summed up in a small number of equations, such as Maxwell's equations for electromagnetism. In similar fashion, the equations here purport to encompass the whole of their given field.

===Simplified Explanations===

;All kinematics equations
:Kinematics is the study of the motion of objects. More specifically, it describes how the location, velocity, and acceleration of an object vary over time. The equation shown contains two of these standard kinematic variables, velocity ''v'' and time ''t'', in addition to several quantities (''E'', ''K0'', and ''ρ'') that are completely unrelated to kinematics.

;All number theory equations
:Number theory is a branch of mathematics concerned primarily with the study of integers. However, the equation shown contains the non-integer Euler's constant ''e'' (approximately 2.718). It also uses the Greek letter π as an integer-valued variable, even though the symbol π is used in mathematics almost exclusively to denote the well-known ''non''-integer circle constant (approximately 3.14159). Even with π treated as a variable here, one of its uses in the equation is still nonsensical. <math>\pi-\infty</math> uses ∞ as if it were a specific number, which it is not, thus giving an undefined result.

;All fluid dynamics equations
:Fluid dynamics try to cover the movement of fluids, and also gases, in a given environment. It has to include turbulences which this formula presents by some other meanings. In fact there is no simple formula to explain fluid dynamics and for example it's impossible to predict the exact shape of a forming cloud over time.

;All quantum mechanics equations
:This formula uses the the typical angel bracket and vertical bar notation used in quantum mechanics. The uppercase letter ''A'' probably indicates ''all'', but only in respect to two dimensions (x,y). An equation covering ''all'' would need at least the missing third dimension and of course the time to cover some dynamics.

;All chemistry equations
:Randall implies that all chemistry is just combustion of chemicals, demonstrated with an incorrect form of a common example chemistry equation of burning Methane and Oxygen (with added heat), to form water and carbon dioxide. However, in this form "HEAT" is an actual molecule, rather than simply indicating the presence of heat to start the reaction. Thus the equation is modified to incorporate the fictional "HEAT" into the reaction. While the H in "HEAT" is the chemical symbol of the element hydrogen, none of the letters E, A, or T are symbols of any actual elements. Also, to account for the second hydrogen in "H(2)EAT" on the products side, the oxygen gas on the reactants side has been altered to be hydroxide, a strong base that would not facilitate traditional combustion.

;All quantum gravity equations
:At first this isn't a equation at all because there is no equal sign or similar between the terms. The notation SU(2) again refers to a two dimensional system but also to symmetries in quantum mechanics like particles always have their anti-particles. Quantum gravity in general hasn't been discovered yet.

;All gauge theory equations
:Gauge theories in physics try to describe the dynamics of elementary particles in the field of the {{w|Quantum field theory}} and lead to the famous {{w|Standard Model}} of particle physics.

;All cosmology equations
:The {{w|Hubble's law}} is a simple explanation how the expansion of the universe appears to work, but there is also a Nobel Prize worthy {{w|Dark energy}} trying to explain the the moving speeds of distant galaxies. All theories are far away to explain the Cosmos at all.

;All truly deep physics equations
:TODO: missing simple explanation

===Technical Explanations===
;All kinematics equations
:<math>E = K_0t + \frac{1}{2}\rho vt^2</math>
:{{w|Kinematics}} describes the motion of objects without considering mass or forces. The latter is described by {{w|Kinetics (physics)|kinetics}}. The two fields get frequently confused due to the similarity of words.

:This equation here literally states: "Energy equals a constant <math>K_0</math> multiplied by time, plus half of density multiplied by speed multiplied by time squared".

:The first term here is hard to interpret: it could be correct if <math>K_0</math> is a constant power applied to the system, but this symbol would more normally be used to denote an initial energy, in which case multiplying by <math>t</math> would be wrong. Alternatively, the term is similar to <math>k_B T</math> (sometimes written as ''kT''), a term that often appears in {{w|Statistical_mechanics|statistical mechanics}} equations, where ''kB'' (or ''k'') is {{w|Boltzmann_constant|the Boltzmann constant}}, and ''T'' is the {{w|Thermodynamic_temperature|absolute temperature}}. In this latter case, the term would have units of energy, consistent with the left side of the equation.

:The second term looks similar to the kinetic energy term <math> \frac{1}{2}\rho v^2 </math> in [http://hyperphysics.phy-astr.gsu.edu/hbase/pber.html the Bernoulli equation] for fluids. (More properly, this is the kinetic energy ''density'' in the fluid).

:The whole equation appears to be a play on the kinematics formula: <math>s = v_0t + \frac{1}{2}\ at^2</math>, where distance travelled (''s'') by a constantly accelerating object is determined by initial velocity (''v0''), time (''t''), and acceleration (''a'')

:Kinematics is often one of the first topics covered in an introductory physics course, both at the high school and freshman college levels. As such, mixing in material from more advanced topics like statistical mechanics and the Bernoulli equation, even if done correctly, would be very confusing for a typical student learning kinematics.

;All number theory equations
:<math>K_n = \sum_{i=0}^{\infty}\sum_{\pi=0}^{\infty}(n-\pi)(i+e^{\pi-\infty})</math>
:{{w|Number theory}} is a branch of mathematics primarily studying the properties of integers.

:Said in English, the equation can be read: "The ''n''th K-number is equal to the sum for all ''i'' from 0 to infinity of the sum for all π from 0 to infinity of ''n'' minus π, multiplied by ''i'' plus ''e'' raised to the power of π minus infinity." (''i'' here is an iteration variable, not the imaginary number constant; ''e'' is Euler's number, approximately 2.718). A twofold misconception can be seen here. The first is the use of π as a variable instead of the circle constant (3.14...). This might be a jab at how in number theory letters and numbers are used interchangeably, but where some letters are suddenly fixed constants.

:Further confusion comes from the use of unusual mathematical models. While the term <math>e^{\pi-\infty}</math> is meaningless when considered in standard ("high school") mathematics, it is valid when considered on the {{w|extended real number line}}, a concept unfamiliar to most non-mathematicians and uncommon in number theory. Naively, this would signify that (with the use of π as a variable) the exponent would range from negative infinity to zero. In fact, assuming ''e'' really does mean Euler's constant (or at least a real number strictly greater than 1) the term would be zero for every π < ∞. Ultimately, the sum diverges for every ''n''.

:The close proximity of the letters i, e and π also evokes {{w|Euler's identity}} <math>e^{i\pi}+1=0</math> (also written <math>e^{i\pi}=-1</math>), without actually using it, especially since both π and i are used as variables here.

;All fluid dynamics equations
:<math>\frac{\partial}{\partial t}\nabla\cdot \rho = \frac{8}{23}
\int\!\!\!\!\!\!\!\!\!\;\;\bigcirc\!\!\!\!\!\!\!\!\!\;\;\int
\rho\,ds\,dt\cdot \rho\frac{\partial}{\partial\nabla}
</math>
:{{w|Fluid dynamics}} describes the movement of non-solid material. In particular for gases, the density <math>\rho</math> is often the most interesting quantity (for liquids, this is often just constant). A unique feature of fluid-dynamic equations is the presence of {{w|Advection|advection terms}}, which take the form of often strange-looking spatial derivatives. This equation turns this up to a new level by differentiating with respect to a differential operator <math>\nabla</math>, which does not make any sense at all. Also it has a contour integral which seems reminiscent to a closed-circle process like in a piston engine, but this does not really fit in the context (differential description of a gas), and it has a pair of {{w|Magic number (programming)|unexplained numbers}} <math>8</math> and <math>23</math>, probably alluding to the {{w|Heat capacity ratio|specific heat ratio}} which is often written out as the fraction <math>\tfrac{7}{5}</math>, whereas most other physics equations [[899: Number Line|avoid including any plain numbers higher than 4]].

;All quantum mechanics equations
:<math>|\psi_{x,y}\rangle = A(\psi) A(|x\rangle \otimes |y\rangle)</math>
:{{w|Quantum mechanics}} is a fundamental theory in physics which describes nature at scales of atoms and below. It typically uses the {{w|Bra–ket notation|bra–ket notation}} in its formulae.

:This equation takes a state psi in the dimensions of x and y and equates it to an operator A performed on psi multiplied by the same operator performed on the tensor product of x and y. Since the state psi is already the tensor product of the states x and y, this is equivalent to performing the same unknown operator twice on psi, and unless this operator is the identity or is its own inverse such as a bit-flip or Hermitian operator, this equation is therefore incorrect.

;All chemistry equations
:<math>\mathrm{CH}_4 + \mathrm{OH} + \mathrm{HEAT} \rightarrow \mathrm{H}_2\mathrm{O} + \mathrm{CH}_2 + \mathrm{H}_2 \mathrm{EAT}</math>
:A {{w|Chemical equation|chemical equation}} represents a chemical reaction as a formula, with the reactant entities on the left-hand side, and the product entities on the right-hand side. The number of each element on the left side must match those on the right side. The energy produced or absorbed in this process is not included in that formula.

:This is a modification of the combustion of methane. The correct form is often taught and a good example problem but obviously there are more chemistry problems.<math>\mathrm{HEAT}</math> is normally shorthand for {{w|activation energy}}, but in Randall's version it's jokingly used as a chemical ingredient and becomes <math>\mathrm{H}_2\mathrm{EAT}</math>, taking the hydrogen atom freed by the combustion equation shown. The proper methane combustion equation would be: <math>\mathrm{CH}_4 + 2 \mathrm{O}_2 \rightarrow 2 \mathrm{H}_2\mathrm{O} + \mathrm{CO}_2</math>

:While <math>\mathrm{OH}</math> often appears in chemical equations in the form of a negatively charged hydroxide group (<math>\mathrm{OH}^-</math>), the left side of the equation involves a bare <math>\mathrm{OH}</math>, possibly the highly unstable hydroxyl radical (although this would typically be written with a leading dot, e.g. <math>\bullet\mathrm{OH}</math>). Similarly, the right side contains an unstable methylene radical which would generally only appear as an intermediate rather than a product.

;All quantum gravity equations
:<math>\mathrm{SU}(2)\mathrm{U}(1) \times \mathrm{SU}(\mathrm{U}(2))</math>
:This is more similar to expressions which appear in {{w|Grand_Unified_Theory|Grand Unified Theory}} (GUT) than general quantum gravity. Unlike some of the other equations, this one has no interpretation which could make it mathematically correct. This is similar to the notations used to describe the symmetry group of a particular phenomena in terms of mathematical {{w|Lie_Group|Lie Groups}}. A real example would be the Standard Model of particle physics which has symmetry according to <math>\rm{SU(3)\times SU(2) \times U(1)}</math>. Here, <math>\rm{SU}</math> and <math>\rm{U}</math> denote the special unitary and unitary groups respectively with the numbers indicating the dimension of the group. Loosely, the three terms correspond to the symmetries of the strong force, weak force and electromagnetism although the exact correspondence is muddied by symmetry breaking and the Higgs mechanism.

:Of course, an expression missing an "=" sign, is difficult to interpret as an "equation", because equations normally express an "equality" of some kind. Nobody knows whether Randal refers to a horse, zebra, donkey or other equine here.

:Randall's version clearly involves some similar groups although without the <math>\times</math> symbol it is hard to work out what might be happening. A term like <math>\rm{SU(U(2))}</math> has no current interpretation in mathematics, if anyone thinks otherwise and possibly has a solution to the quantum gravity problem they should probably get in touch with someone about that.

;All gauge theory equations
:[[File:All gauge theory equations.png]]
:In physics, a {{w|Gauge theory|gauge theory}} is a type of field theory which is invariant to local transformations. The term gauge refers to any specific mathematical formalism to regulate redundant degrees of freedom.

:This equation looks broadly similar to the sorts of things which appear in gauge theory such as the equations which define {{w|Yang–Mills_theory#Quantization|Yang-Mills Theory}}. By the time physics has got this far in, people have normally run out of regular symbols making a lot of the equations look very daunting. The actual equations in this field rarely go far beyond the Greek alphabet though and no-one has yet to try putting hats on brackets. The appearance of many sub- and superscripts is normal (this links to the group theory origins of these equations) and for the layperson it can be impossible to determine which additions are labels on the symbols and which are indices for an {{w|Einstein_notation|Einstein Sum}}.

:The left-hand side <math>S_g</math> is the symbol for some {{w|Action_(physics)|action}}, in Yang-Mills theory this is actually used for a so-called "ghost action". On the right-hand side we have a large number of terms, most of which are hard to interpret without knowing Randall's thought processes (this is why real research papers should all label their equations thoroughly). The <math>\frac{1}{2\bar{\varepsilon}}</math> looks like a constant of proportionality which often appears in gauge theories. The factor of <math>i = \sqrt{-1}</math> is not unusual as many of these equations use complex numbers. The <math>\eth</math> symbol looks similar to a <math>\partial</math> partial derivative symbol especially as the {{w|Dirac_equation#Covariant_form_and_relativistic_invariance|Dirac Equation}} uses a slashed version as a convenient shorthand.

:The rest of the equation cannot be mathematically correct as the choice of indices used does not match that on the left-hand side (which has none). In particle physics subscripts (or superscripts) of greek letters (usually <math>\mu</math> or <math>\nu</math>) indicate terms which transform nicely under Lorentz transformations (special relativity). Roman indices from the beginning of the alphabet relate to various gauge transformation propetries, the triple index seen on <math>p^{abc}_v</math> would likely come from some <math>\rm{SU(3)}</math> transformation (related to the strong nuclear force). Since <math>S_g</math> has none of these (and is thus a scalar which remains constant under these operations), we would need the right-hand side to behave in the same way. Most of the indices which appear are unpaired and so will not result in a scalar making the equation very wrong. For those not familiar with this type of equation, this is similar to the mistake of messing up units, for instance setting a distance equal to a mass.

;All cosmology equations
:<math>H(t) + \Omega + G \cdot \Lambda \, \dots \begin{cases} \dots > 0 & \text{(Hubble model)} \\ \dots = 0 & \text{(Flat sphere model)} \\ \dots < 0 & \text{(Bright dark matter model)} \end{cases}
</math>
:This is a parody of equations defining the {{w|Hubble's_law#Derivation_of_the_Hubble_parameter|Hubble Parameter}} <math>H(t)</math> although it looks like Randall has become bored and not bothered to finish his equation. Such equations usually have several <math>\Omega</math> terms representing the contributions of different substances to the energy-density of the Universe (matter, radiation, dark energy etc.). In this context <math>G</math> could be Newton's constant and <math>\Lambda</math> is the cosmological constant (energy density of empty space) although seeing them appear multiplied and on the same footing as <math>H</math> is unusual (the dot is entirely unnecessary). Choosing to make <math>H</math> a function of time <math>t</math> and not of redshift <math>z</math> is also unusual.

:The second section looks like the inequalities used to show how the equation varies with the shape of the Universe, based on the value of the curvature parameter <math>\Omega_k</math>. A value of 0 indicates a flat Universe (this is more or less what we observe) while a positive /negative value indicates an open /closed curved Universe. Randall's choice of labels further makes fun of the field as both a flat sphere and bright dark matter are oxymoronic terms which would involve some rather strange model universes.

;All truly deep physics equations
:[[File:All truly deep physics equations.png]]
:<math>\hat H</math> is the Hamiltonian operator, which when applied to a system returns the total energy. In this context, U would usually be the potential energy. However, there is also a subscript 0 and a diacritic marking indicating some other variable. Much of physics is based on Lagrangian and Hamiltonian mechanics. The Lagrangian is defined as <math>\hat L = \hat K - \hat U </math> with K being the kinetic energy and U the potential. Hamiltonian mechanics uses the equation <math>\hat H = \hat K + \hat U </math>. The Hamiltonian must be conserved so taking the time derivative and setting it equal to zero is a powerful tool. The "principle of least action" allows most modern physics to be derived by setting the time derivative of the Lagrangian to zero.

The title text states that the electromagnetism equation is the same as the fluid dynamics equation, but with the arbitrary 8 and 23 replaced with the permittivity and permeability of free space is likely because electromagnetism equations often have relations to fluid dynamics, and because those two constants appear in the vast majority of electromagnetism equations.

==Transcript==
:[Nine equations are listed, three in the top row and two in each of the next three rows. Below each equation there are labels:]

:E = K0t + 1/2 ρvt2
:All kinematics equations

:Kn = ∑i=0∞∑π=0∞(n-π)(i-eπ-∞)
:All number theory equations

:∂/∂t ∇ ⋅ ρ = 8/23 (∯ ρ ds dt ⋅ ρ ∂/∂∇)
:All fluid dynamics equations

:|ψx,y〉 = A(ψ) A(|x〉⊗ |y〉)
:All quantum mechanics equations

:CH4 + OH + HEAT → H2O + CH2 + H2EAT
:All chemistry equations

:SU(2)U(1) × SU(U(2))
:All quantum gravity equations

:Sg = (-1)/(2ε̄) i ð (̂ ξ0 +̊ pε ρvabc η0 )̂ f̵a0 λ(ʒ̆) ψ(0a)
:All gauge theory equations

:[There is a brace linking the three cases together.]
:H(t) + Ω + G⋅Λ ...
:... > 0 (Hubble model)
:... = 0 (Flat sphere model)
:... < 0 (Bright dark matter model)
:All cosmology equations

:Ĥ - u̧0 = 0
:All truly deep physics equations

{{comic discussion}}

[[Category:Science]]
[[Category:Physics]]
[[Category:Math]]
[[Category:Chemistry]]
[[Category:Astronomy]]

Talk:2064: I'm a Car

2018-10-26T18:26:20Z

162.158.74.57:

Is that a Chevy Volt? --[[Special:Contributions/172.69.62.196|172.69.62.196]] 04:30, 26 October 2018 (UTC)
:Using google image search I could find various different taillight configurations on Chevrolet Volt's, but non where the lights extend to the trunk, and also downward on the site of the trunk. They are either above each other, or extending to the trunk. The one in the comic has both.--[[User:Lupo|Lupo]] ([[User talk:Lupo|talk]]) 07:51, 26 October 2018 (UTC)

Cars are getting more intelligent and the voters seem to get dumber. This comic states that some cars are more intelligent than the average voters. [[Special:Contributions/141.101.104.209|141.101.104.209]] 06:48, 26 October 2018 (UTC)

No matter how smart the car is it would need to meet eligibility requirements to vote. Cars are typically registered in a jurisdiction but are generally not recognized as citizens or residents for voting purposes. Only some cars meet the age requirements, e.g. in the United States the median age of an automobile was [https://news.ihsmarkit.com/press-release/automotive/average-age-vehicles-road-remains-steady-114-years-according-ihs-automotive 11.4 years] in 2014 while a voter must be at least 18 years of age to vote in US Federal elections. As for the title text, cars are generally incapable of reproduction [citation needed], ineligible for adoption [citation needed], and generally do not attend school [citation needed], making this scenario multiply implausible [[User:ChronoCronut|ChronoCronut]] ([[User talk:ChronoCronut|talk]]) 09:00, 26 October 2018 (UTC)
: "Only some cars meet the age requirements" Right, but they are very mature for their age. xD [[Special:Contributions/162.158.90.114|162.158.90.114]] 11:35, 26 October 2018 (UTC)
: It's time to start the car suffrage movement! [[User:N0lqu|-boB]] ([[User talk:N0lqu|talk]]) 13:13, 26 October 2018 (UTC)

"The entire comic seems to be related to self-driving cars, which has been a recurring subject on xkcd. As they first begins to drive by themselves, the next step is voting and later getting car babies that can grow up and become honor students." Actually, I think that this comic is about bumper stickers on cars. Of course people put bumper stickers on their cars to make a statement about themselves, but what if the bumper stickers were actually a statement by the car, not the person driving it. That's another common theme. [[User:Andyd273|Andyd273]] ([[User talk:Andyd273|talk]]) 12:26, 26 October 2018 (UTC)
: I agree the comic is about bumper stickers which use "first person" wording taken literally as being the cars themselves talking. However as we hear and see more about self driving cars, and get closer to mythical artificial intelligence, the day may come when this joke about literality could cease to be a joke. [[User:N0lqu|-boB]] ([[User talk:N0lqu|talk]]) 14:25, 26 October 2018 (UTC)

If this car made one of the questionable votes against network neutrality?

The first thing that jumped to my mind was that it also mixed in the security issues arising due to the "Internet of Things" problems. Admittedly, most IoT devices are used in DoS attacks and are generally not used as general purpose hacking jump boxes, but I see no reason that cellular network equipped cars could not be hacked and used as a source for voting in digital elections. Adrian Colyer has a great synopsis of two vehicle papers on his blog: https://blog.acolyer.org/2015/12/02/carshark/ and https://blog.acolyer.org/2015/12/03/fast-and-vulnerable/ . [[User:Tovodeverett|Tovodeverett]] ([[User talk:Tovodeverett|talk]]) 13:35, 26 October 2018 (UTC)
: But that would still be someone (a human) voting, albeit using the car as a vehicle [sic] for that vote. So the bumper sticker isn't being literal in this case, the car itself didn't vote, and so the joke doesn't work. [[User:N0lqu|-boB]] ([[User talk:N0lqu|talk]]) 18:22, 26 October 2018 (UTC)

I put a citation needed tag in as a joke, and someone actually found a source for it.

2059: Modified Bayes' Theorem

2018-10-15T20:02:24Z

162.158.74.57: Corrected a } to a ) and added a quip to the end.

{{comic
| number = 2059
| date = October 15, 2018
| title = Modified Bayes' Theorem
| image = modified_bayes_theorem.png
| titletext = Don't forget to add another term for "probability that the Modified Bayes' Theorem is correct."
}}

==Explanation==
{{incomplete|When using the Math-syntax please also care for a proper layout. Please edit the explanation below and only mention here why it isn't complete. Do NOT delete this tag too soon.}}
{{w|Bayes' Theorem}} is an equation in statistics that gives the probability of a given hypothesis accounting not only for a single experiment or observation but also for your existing knowledge about the hypothesis, i.e. its prior probability. Randall's modified form of the equation also purports to account for the probability that you are indeed applying Bayes' Theorem itself correctly by including that as a term in the equation.

Bayes' theorem is:

<math>P(H \mid X) = \frac{P(X \mid H) \, P(H)}{P(X)}</math>,
where
*<math>P(H \mid X)</math> is the probability that <math>H</math>, the hypothesis, is true given observation <math>X</math>. This is called the ''posterior probability''.
*<math>P(X \mid H)</math> is the probability that observation <math>X</math> will appear given the truth of hypothesis <math>H</math>. This term is often called the ''likelihood''.
*<math>P(H)</math> is the probability that hypothesis <math>H</math> is true before any observations. This is called the ''prior'', or ''belief''.
*<math>P(X)</math> is the probability of the observation <math>X</math> regardless of any hypothesis might have produced it. This term is called the ''marginal likelihood''.

The purpose of Bayesian inference is to discover something we want to know (how likely is it that our explanation is correct given the evidence we've seen) by mathematically expressing it in terms of things we can find out: how likely are our observations, how likely is our hypothesis ''a priori'', and how likely are we to see the observations we've seen assuming our hypothesis is true. A Bayesian learning system will iterate over available observations, each time using the likelihood of new observations to update its priors (beliefs) with the hope that, after seeing enough data points, the prior and posterior will converge to a single model.

If <math>P(C)=1</math> the modified theorem reverts to the original Bayes' theorem (which makes sense, as a probability one would mean certainty that you are using Bayes' theorem correctly).

If <math>P(C)=0</math> the modified theorem becomes <math>P(H \mid X) = P(H)</math>, which says that the belief in your hypothesis is not affected by the result of the observation (which makes sense because you're certain you're misapplying the theorem so the outcome of the calculation shouldn't affect your belief.)

This happens because, if you apply the original theorem, the modified theorem can be rewritten as: <math>P(H \mid X) = P(H)(1-P(C)) + P(H \mid X)P(C)</math>. This is the {{w|Linear interpolation|linear-interpolated}} weighted average of the belief you had before the calculation and the belief you would have if you applied the theorem correctly. This goes smoothly from the not believing your calculation at all, keeping the same belief as before if <math>P(C)=0</math> to changing your belief exactly as Bayes' theorem suggests when <math>P(C)=1</math>.

<math>1-P(C)</math> is the probability that you are using the theorem incorrectly.

As an equation, the rewritten form makes no sense. <math>P(H \mid X) = P(H)(1-P(C)) + P(H \mid X)P(C)</math> is strangely self-referential and reduces to the piecewise equation <math>\begin{cases}P(H \mid X) = P(H) & P(C) \neq 1 \\ 0 = 0 & P(C) = 1 \end{cases}</math>. However, the Modified Bayes Theorem includes an extra variable not listed in the conditioning, so a person with an AI background might understand that Randal was trying to write an expression for updating <math>P(H \mid X)</math> with knowledge of <math>C</math> i.e. <math>P(H \mid X,C)</math>, the belief in the hypothesis given the observation <math>X</math> and the confidence that you were applying Bayes' theorem correctly <math>C</math>, for which the expression <math>P(H \mid X,C) = P(H)(1-P(C)) + P(H \mid X)P(C)</math> makes some intuitive sense.

The title text suggests that an additional term should be added for the probability that the Modified Bayes Theorem is correct. But that's *this* equation, so it would make the formula self-referential. It could also result in an infinite regress -- we'd need another term for the probability that the version with the probability added is correct, and another term for that version, and so on. It's also unclear what the point of using an equation we're not sure of is (although sometimes we can: {{w|Newton's Laws}} are not as correct as Einstein's {{w|Theory of Relativity}} but they're a reasonable approximation in most circumstances. Alternatively, ask any student taking a difficult exam with a formula sheet.).

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}

:Modified Bayes' theorem:

:P(H|X) = P(H) × (1 + P(C) × ( P(X|H)/P(X) - 1 ))

:H: Hypothesis
:X: Observation
:P(H): Prior probability that H is true
:P(X): Prior probability of observing X
:P(C): Probability that you're using Bayesian statistics correctly

{{comic discussion}}

[[Category:Statistics]]

Talk:2054: Data Pipeline

2018-10-04T00:15:48Z

162.158.74.57:

tried my hand at transcipts again, hope i did ok. [[User:Nintendo Mc|Nintendo Mc]] ([[User talk:Nintendo Mc|talk]]) 15:32, 3 October 2018 (UTC)

Oddly prescient, as always. I've just finished writing a fully automated data pipeline that ingests multiple data sources (both manual and automated input), has API support, a frontend, and email dispatch capabilities entirely in Google Sheets. It was about 3x faster to code than doing it right. [[Special:Contributions/172.68.65.6|172.68.65.6]] 16:48, 3 October 2018 (UTC)

Just added a line about how this is a logical continuation of the Code Quality series - given it's the same two people, this should be uncontroversial. Is it worth adding a new category for "Code Quality" to group these (and likely subsequent comics) together? [[User:Grimreaperwithalawnmower|Grimreaperwithalawnmower]] ([[User talk:Grimreaperwithalawnmower|talk]]) 17:20, 3 October 2018 (UTC)

What could we still add to the transcript? I don't think it really needs any more transcripting so maybe we should remove the marker. [[User:Kwonunn|Kwonunn]] ([[User talk:Kwonunn|talk]]) 18:50, 3 October 2018 (UTC)

No comment about the "roll over" text (excuse me if I have the name wrong). I think this is a comment about the shear computing power, battery life and superior connectivity of modern mobile phones compared to laptops. [[User:RIIW - Ponder it|RIIW - Ponder it]] ([[User talk:RIIW - Ponder it|talk]]) 19:05, 3 October 2018 (UTC)
: IIRC, it's generally called "hover text."

Re: superior connectivity of mobile phones, see https://xkcd.com/1865/

2003: Presidential Succession

2018-06-06T05:20:11Z

162.158.74.57: Second Report of the Continuity of Government Commission link

{{comic
| number = 2003
| date = June 6, 2018
| title = Presidential Succession
| image = presidential_succession.png
| titletext = Ties are broken by whoever was closest to the surface of Europa when they were born.
}}

==Explanation==
{{incomplete|Created by a BOT - Please change this comment when editing this page. Do NOT delete this tag too soon.}}

The {{w|United States presidential line of succession}} is an order of people who serve as president if the current incumbent president is incapacitated, dies, resigns, or is removed from office. This is another comic in the continuing line of comics about American politics, especially after the election of Donald Trump as President in 2016.

The full text of the Second Report of the Continuity of Government Commission can be found here: https://www.brookings.edu/wp-content/uploads/2016/06/06_continuity_of_government.pdf

# President
# Vice president
# Secretary of State
# Secretary of Defense
# Secretary of Homeland Security
# Attorney General
# Five people who do not live in Washington DC, Nominated at the start of the president's term and confirmed by the Senate
# Tom Hanks
# State Governors, in descending order of state population at last census
# Anyone who won an Oscar for playing a governor
# Anyone who won a Governor's award for playing someone named Oscar
# Kate McKinnon, if available
# Billboard year-end hot 100 singles artists #1 through #10 (for groups, whoever is credited first in name, liner notes, etc)
# The top 5 US astronauts in descending order of total spaceflight time
# Serena Williams (or, if she lost her most recent match, whoever beat her)
# The most recent season NBA, NFL, MLB, and NHL MVPs
# '''Bill Pullman and his descendants by absolute primogeniture'''. Bill Pullman is an American actor, known among other roles for playing President Thomas J. Whitmore in Independence Day. Absolute primogeniture is a form of succession where the oldest direct descendant receives the title.
# The entire line of succession to the British throne
# The current champion of the Nathan's Hot Dog Eating contest
# '''All other US citizens, chosen by a 29-round single-elimination Jousting tournament.''' Effective for a population up to 536,870,912 individuals, although an additional round can be added should the population grow further.

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
: A proposal for a new presidential line of succession
: Current politics aside, most experts agree the existing process is flawed. The presidential succession act of 1947 is probably unconstitutional on several counts, and there are many practical issues with the system as well.
: (for more, see the surprisingly gripping [https://www.brookings.edu/research/the-continuity-of-the-presidency-the-second-report-of-the-continuity-of-government-commission/ ''Second Report of the Continuity of Government Commission'', June 2009]).
: Proposed line of succession:
:# President
:# Vice president
:# Secretary of State
:# Secretary of Defense
:# Secretary of Homeland Security
:# Attorney General
:# Five people who do not live in Washington DC, Nominated at the start of the president's term and confirmed by the Senate
:# Tom Hanks
:# State Governors, in descending order of state population at last census
:# Anyone who won an Oscar for playing a governor
:# Anyone who won a Governor's award for playing someone named Oscar
:# Kate McKinnon, if available
:# Billboard year-end hot 100 singles artists #1 through #10 (for groups, whoever is credited first in name, liner notes, etc)
:# The top 5 US astronauts in descending order of total spaceflight time
:# Serena Williams (or, if she lost her most recent match, whoever beat her)
:# The most recent season NBA, NFL, MLB, and NHL MVPs
:# Bull Pullman and his descendants by absolute primogeniture
:# The entire line of succession to the British throne
:# The current champion of the Nathan's Hot Dog Eating contest
:# All other US citizens, chosen by a 29-round single-elimination Jousting tournament.

: Title text: Ties are broken by whoever was closest to the surface of Europa when they were born.

{{comic discussion}}

Talk:1927: Tinder

2017-12-12T14:39:31Z

162.158.74.57: Nevermind

This comic reminds me of [http://xkcd.com/582] (because of using an inappropriate form of communication in an emergency).

"Cueball is violating the law by using a cell phone that is not in "airplane mode" when on an airplane.", really? I don't think it's an actual "law" since the entire concept is based on garbage and bullshit (you'd have to be in the cockpit AND within about 2 feet of the equipment in question in order to interfere with it. For both airplanes and hospitals the rule is actually just to try to bully people into being considerate to the people around them). I believe it's just a rule set by the FAA or some other governing body. Also, I believe said rule is limited to during take off and landing, not the entire flight. [[User:NiceGuy1|NiceGuy1]] ([[User talk:NiceGuy1|talk]]) 07:31, 12 December 2017 (UTC)

*I also wondered about "Cueball is violating the law by using a cell phone that is not in "airplane mode" when on an airplane.", but for a different reason: How do we now that the phone is not in airplane mode, but which activated wifi? As some airlines (at least in Europe) offer wifi on board, it would be quite common (and allowed) to be able to use online services on a phone while flying (but not other wireless signals, e.g. phone calls). [[User:Scm|Scm]] ([[User talk:Scm|talk]]) 09:00, 12 December 2017 (UTC)

:: Actually, you're correct (at least in the US). However, some countries has actual laws that either explicitly do not allow phone usage on a plane (e.g. Japan) or do not allow it implicitly (In Russia, using licensed radio frequencies above a certain height is not allowed unless the regulator allows that use) - [[Special:Contributions/172.68.144.169|172.68.144.169]] 10:29, 12 December 2017 (UTC)

:to suggest that there is a meaningful difference (in this context) between a rule and a law is silly; the FAA can (and has) fined individuals for using cell phones *during takeoff*. Does it matter if the fine was for breaking a rule or for breaking a law?
:More importantly, in the scenario shown Cueball has somehow found himself in the role of PIC (pilot in command) and in an emergency situation. Assuming he declares the emergency he can freely violate any and all FAA rules that he believes will help in resolving the emergency (that's the FAA's rule).

Talk:1927: Tinder

2017-12-12T14:37:40Z

162.158.74.57: /* Alternative Explanation */ new section

1766: Apple Spectrum

2016-12-02T13:32:26Z

162.158.74.57: /* Explanation */ For this article all apples are eating apples

{{comic
| number = 1766
| date = November 30, 2016
| title = Apple Spectrum
| image = apple_spectrum.png
| titletext = If I were trapped on a desert island, and could have an unlimited supply of any one type of apple, I'd be like, "How did this situation happen?"
}}

==Explanation==

The comic shows a {{w|spectrum}} of different types of apples, with {{w|Red Delicious}} towards the bad end of the spectrum, and {{w|Honeycrisp}} towards the good end of the spectrum. Although most spectra are only one-dimensional, {{w|Granny Smith}} is on some side branch, implying that the taste is so different from the other two that it deserves its own category. (Perhaps this refers to the fact that the Granny Smith is primarily a cooking apple while the named apples on the main spectrum are normally eaten raw. Additionally, Granny Smith apples have a tart, or sour, flavor with a subtle sweetness.) The rest of the apple types fall somewhere in between. [[Randall]] has previously shown his disdain for Red Delicious apples in footnote 1 in [https://books.google.com/books?id=tgZIBAAAQBAJ&lpg=PP1&pg=PA97#v=onepage&q&f=false this what if]; he also ranked green apples as tastier than red apples in [[388: Fuck Grapefruit]].

In the title text, Randall observes a common type of hypothetical question designed as a creative way to inquire about a person's preferences: If he were on a desert island with an unlimited access to something they like -- in this case, unlimited supply of any one type of apple -- what would he choose? However, Randall gives an unorthodox and unexpected answer to the typically playful hypothetical by taking it literally and questioning how such a situation would occur. How did he get stuck on the island, and how did he get a literally unlimited supply of apples? In reality, a desert island is unlikely to have an unlimited supply of any food{{Citation needed}}, let alone apples.

==Transcript==
[A mapping, showing types of apples. Each apple is in a bubble]
<div style="text-align: center;">
Bad <-- Red Delicious -- Regular apples -- Honeycrisp --> Good
 |
 |
 Granny Smith
 |
 V
 Doing their own thing
</div>

{{comic discussion}}

388: Fuck Grapefruit

2016-12-01T02:30:05Z

162.158.74.57: /* Table */ - corrected pomegranate entry as the seeds (arils) are actually edible.

{{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 of a chart where [[Randall]] has plotted {{w|fruits}} according to two criteria: ease/difficulty to eat on the horizontal axis, and tastiness on the vertical 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.

For instance, {{w|pineapples}} are deemed fairly tasty but very difficult to eat, whereas (seeded) {{w|grapes}} are very tasty and somewhat easy, and logically {{w|Grape#Seedless_grapes|seedless grapes}} are roughly equally tasty but easier to eat.

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; 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.

The individual ratings of each fruit are subjective; very obviously in the case of tastiness, and more subtly for difficulty. Randall does not explain his criteria for ranking the difficulty of each fruit, and it is likely based on simply personal experiences. Someone who has grown up in an area where pineapples are plentiful is likely to be more adept at skillfully preparing them. The discrepancies between how Randall has rated certain fruits and how others believe they should have been rated caused a [[#Controversy|surprising level of controversy]].

According to the chart, {{w|Grapefruit}} is the third hardest fruit to eat as well as the second least tasty 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. Hence Randall's quip in the title: "Fuck grapefruit".

In the title text Randall mentions {{w|coconuts}}. Randall mentions that he would have to put them so far down to the left on the chart (not far down, just far down towards the left), that they would not fit in this chart. He thus states that it is so much more difficult to eat (especially to open) coconuts than the usual mainstream fruits such as the ones plotted here. If he did include coconuts in the chart the rest of the fruits would all be pushed to the right side of the chart. He does not say that he does not like to eat the fruit. (Although it has "{{w|nut}}" in its name, the coconut is actually a {{w|Drupe|stone fruit}} and thus belongs on a chart of fruit.) Having spent half an hour trying (in vain?) to open a coconut, Randall also only has one thing to say about them: "Fuck coconuts".

In [[1701: Speed and Danger]] another scatter plot shows exactly what happens when one point is inserted into such a plot if it is far removed from all the other points, in this case even on both axes.

===Table===
The table below lists approximate coordinates for each fruit using a scale of -100% (untasty/difficult) to 100% (tasty/easy). The coordinates are based on the included fruits, any new items added outside the current range (e.g. Coconuts) would cause the scales to be reassigned, and thus change the coordinate values of existing items.

The coordinates have been found by measuring each fruit from the center of the drawing (not center of mass, but center from left to right/top to bottom) to the two axes. The axes are hand drawn which is clearly visible. The numbers have been obtained be measuring to the nearest point of each axis, not taking into account that the axes are not perfect straight perpendicular lines.

{| class="wikitable sortable"
! Tastiness !! Easiness !! Fruit !! Comments
|-
| 100% || 68% || {{w|Peaches}} || Among Randall's favorite fruits, as it is the one deemed most tasty and it is far more tasty than the four fruits that are deemed easier to eat. While it does contain a stone/pit which may be annoying due to disposal of the sticky remains, it's large enough to eat around and Randall apparently sees it not to be that big a problem in the long run.
|-
| 85% || 13% || {{w|Grape|Seeded grapes}} || Randall apparently subscribes to the theory that seeded grapes are tastier than unseeded grapes due to higher genetic diversity, but are harder to eat because of the seeds.
|-
| 75% || 75% || {{w|Strawberries}} || Actually not a berry but an {{w|accessory fruit}}, like many of the other fruits on the chart
|-
| 72% || 100% || {{w|Grape#Seedless_grapes|Seedless grapes}} || Randall apparently subscribes to the theory that seeded grapes are tastier than unseeded grapes due to higher genetic diversity, but are harder to eat because of the seeds.
|-
| 68% || -100% || {{w|Pineapples}} || Requires a knife to prepare, and can be tricky to dissect without wasting a lot of the fruit.
|-
| 58% || 87% || {{w|Blueberries}} || Usually not listed as a fruit but as a {{w|berry}} although this is still a type of fruit.
|-
| 38% || 42% || {{w|Cherries}} || Containing a stone/pit which may be annoying due to disposal of the sticky remains and taking care not to swallow them.
|-
| 37% || 66% || {{w|Pear}}s || Most people will not eat the core of the pear and is thus left with some sticky part that need to be disposed.
|-
| 22% || 79% || {{w|Green apples}} || Most people will not eat the apple core and is thus left with some sticky part that need to be disposed. It is unclear why green apples are shown as tastier than red.
|-
| 17% || 59% || {{w|Plums}} || Containing a stone/pit which may be annoying due to disposal of the sticky remains and taking care not to swallow them.
|-
| 15% || -20% || {{w|Watermelons}} || Surprisingly considered by Randall to be easier than oranges, which are fairly easy to peel. A watermelon is larger, so the effort to reward ratio is better, but this should't affect its 'ease of eating' position. On the other hand, it is easy to cut a watermelon into edible pieces. You cannot cut an orange like this and they can sometimes be very difficult to peel and you will get very sticky when trying. This can be avoided with the watermelon.
|-
| -12% || 79% || {{w|Apple|Red apples}} || Most people will not eat the apple core and is thus left with some sticky part that need to be disposed. It is unclear why green apples are shown as tastier than red; in his "What If?" book, Randall mentions a specific dislike of "red delicious" apples.
|-
| -18% || 16% || {{w|Bananas}} || Shown in the chart as difficult to eat, even though they are among the most easily peeled fruit. This could be because of the skin which must be disposed of, or the stringy pith which some people refuse to eat and thus have to pick off. Also you do have to peel it, which is not the case for the easier fruits.
|-
| -20% || -85% || {{w|Pomegranates}} || Pomegranates have a very large number of tart, juice-filled arils surrounded in inedible pith and a fairly tough skin. Retrieving the arils is notoriously messy.
|-
| -46% || -49% || {{w|Oranges}} || Considered more difficult than lemons, perhaps due to the layer of pith which is rarely encountered when preparing lemons.
|-
| -74% || 26% || {{w|Tomatoes}} || The culinary arts, nutritional sciences, and United States tax and customs regulations all treat tomatoes as a {{w|vegetable}}, mostly due to its taste. In the botanical sense however, it is actually a fruit (specifically, a {{w|berry}}).
|-
| -86% || -75% || {{w|Grapefruit}} || A very difficult fruit to peel, and thus eat, and also deemed very untasty.
|-
| -100% || -15% || {{w|Lemons}} || Considered easier than oranges, perhaps due to the layer of pith which is rarely encountered when preparing lemons. Very untasty in and of themselves; lemons are a common baking ingredient, but are so sour they are rarely eaten as a fruit.
|}

===Controversy===
As evident from the above section, and according to [http://blog.xkcd.com/2008/02/25/fruit-opinions/ FRUIT OPINIONS!] on the [http://blog.xkcd.com/ Blag], 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''.
*{{w|Cunnilingus}} see [[136: Science Fair]].
*{{w|List of Barack Obama presidential campaign endorsements, 2008|The Obama endorsement}} See [http://blog.xkcd.com/2008/01/28/obama/ Politics] also from the Blag.
**The only comic mentioning {{w|Obama}} before this comic was [[360: Writers Strike]].
*{{w|4chan}} is tiny on the map of the internet called [[256: Online Communities]]. (See the small island to the far right - left of "dragons" in the sentence ''Here there be anthromorphic dragons''.)
**Not to be confused with the comic that is actually named [[195: Map of the Internet]].

==Transcript==
:[An X-Y scatter plot of fruit where both axes have arrows in both ends. At the end of each arrow is a label.]
:[The X-axis from left to right:]
:Difficult
:Easy
:[The Y-axis from top to bottom:]
:Tasty
:Untasty

:[The fruit names are listed here below from top to bottom according to the how tasty the fruit is, not necessarily in the same order that the names are written if one fruit is tall/large and the other low:]
:Peaches
:Seeded grapes
:Strawberries
:Seedless grapes
:Pineapples
:Blueberries
:Cherries
:Pears
:Green apples
:Plums
:Watermelons
:Red apples
:Bananas
:Pomegranates
:Oranges
:Tomatoes
:Grapefruit
:Lemons

{{comic discussion}}

[[Category:Comics with color]]
[[Category:Scatter plots]]
[[Category:Rankings]]
[[Category:Food]]