explain xkcd - User contributions [en]

Talk:5: Blown apart

2022-11-30T22:26:31Z

Flukx: explain empty product

No 70s were harmed in the making of this comic. '''[[User:Davidy22|Davidy22]]'''[[User talk:Davidy22|<tt>[talk]</tt>]] 14:06, 8 January 2013 (UTC)

Also, the 70 is black, and, in a subtractive colour system, black = red+green+blue. [[Special:Contributions/108.162.216.85|108.162.216.85]] 19:14, 30 September 2015 (UTC)
: ... or rather black = magenta+yellow+cyan (red, green, blue are used in additive colour system), I suppose. Then again, who has magenta, yellow, cyan pens available during a boring lecture? [[User:Hagman|Hagman]] ([[User talk:Hagman|talk]]) 22:26, 2 November 2015 (UTC)
::No it is the subtractive color system that is refereed as the additive ends up white. But true about the colors, but when mixing the primary colors magenta+yellow+cyan two by two you get red, green, blue, which would then in that system also mix to black! Have added this to the explanation. So thanks to both of you. --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 18:18, 3 August 2016 (UTC)

I always read the factors and as 7, 5, and N. Then I realize N must be 2, and finally that it's literally 2. {{unsigned ip|162.158.222.94}}

I think it's worth keeping the message around that was just edited in and then out again: The bomb is PRIMED, that may be the reason why it makes PRIME numbers. [[User:Fabian42|Fabian42]] ([[User talk:Fabian42|talk]]) 19:03, 14 June 2018 (UTC)
:Thanks for your critics but that sentence explains nothing. There is no bomb mentioned in the comic, it's an exploding package. And was it drunken, prepared, armed (obviously it was), or a mathematic variable like x' (x primed) referring to the prime symbol. You can find even more meanings of this simple word. I also don't understand why it should be ''the reason''. Bombs are often armed but they don't produce prime factors on detonation. The explanation should be no puzzle game. --[[User:Dgbrt|Dgbrt]] ([[User talk:Dgbrt|talk]]) 19:53, 14 June 2018 (UTC)

"70 has other factors, including 1, 10, 14, 35, and 70, but 2, 5, and 7 are the only factors that are prime. All other factors of 70 can be formed by choosing zero, two, or three of the prime factors and multiplying them together." This is incorrect. You can not multiply zero, two, or three of the prime factors to obtain 1. [[User:Nitpicking|Nitpicking]] ([[User talk:Nitpicking|talk]]) 02:33, 25 November 2021 (UTC)
:Usually in math, we consider the empty product to be equal to 1 because multiplying by 1 does nothing and adding zero factors to a product does nothing as well. So in this interpretation we obtain 1 by multiply zero of the prime factors. I opt for keeping the text the way it is. --[[User:Flukx|Flukx]] 23:35 30 Nov 2022

2658: Coffee Cup Holes

2022-08-13T11:19:58Z

Flukx: IDK explained

{{comic
| number = 2658
| date = August 12, 2022
| title = Coffee Cup Holes
| image = coffee_cup_holes.png
| titletext = Theoretical physicist: At the Planck length, uncountably many.
}}

==Explanation==
{{incomplete|Created by a CAFFEINE MOLECULE WITH A HOLE DRILLED IN ITS SIDE. Do NOT delete this tag too soon.}}

[[File:Mug and Torus morph.gif|thumb|150px|The coffee cup and donut shown in this animation both have genus one.]]

This comic depicts people in different fields of study answering the question, "How many holes are there in a coffee cup?" This question can have multiple interpretations, in particular concerning the definition of a hole.

[[Ponytail]], a {{w|topology|topologist}}, states the coffee cup belongs in the {{w|Genus (mathematics)#Topology|genus}} of one hole. A common joke is that topologists can't tell the difference between a coffee cup and a donut since they're homeomorphic to each other — they have the same genus.  From the topologist's point of view, the coffee cup definitely has one hole. See [[2625: Field Topology]] for more information about topology.

[[Hairy]], a normal person is not sure, (The acronym "IDK" stands for "I don't know".) and asks for clarification about whether the opening at the top counts as a hole. This shows flaws in the question, which suffers from the mathematically imprecise, ambiguous common usage of the word hole. Topologists would refer to the opening as a concavity, not a hole, and while they consider such geometrical properties generally outside their field, most practical applications of topolgy do involve geometrical components.{{cn}}

[[File:Double torus illustration.png|thumb|150px|A genus-2 surface]]

[[Hairbun]], a philosopher, answers the question with an elucidating counter-question, considering a hypothetical scenario. Drilling a new hole should increase the number of holes by one, and after the hole has been drilled, a common teacup or mug has two holes according to topologists. Since drilling a hole increases the number of holes by one, the philosopher's question requires the original questioner to reveal the answer to their own question.

[[Cueball]], a chemist, looks at the cup on a molecular level, which naturally means it has lots and lots of holes: 1,000,000,000,000,000,000,000 (1021 or 1 sextillion) “in the [https://chemapps.stolaf.edu/jmol/jmol.php?model=CN1C%3DNC2%3DC1C%28%3DO%29N%28C%28%3DO%29N2C%29C caffeine] alone.” The implication is that there are more in the cup itself, depending on what material it’s made out of. Also, the coffee itself could have other holes, depending on the type of coffee. For example, espresso contains significant amounts of niacin and riboflavin, each of which has at least one hole in its chemical structure. However, this ignores the fact that bonds are not discrete sticks as portrayed in many molecular models. The "holes" in the middle of a caffeine molecule are not completely empty but instead merely have lower electron densities/probabilities. In a {{w|space-filling model}}, a caffeine molecule has zero holes. So the point-cloud duality of electron orbitals and bonds might not satisfy a topologist's, normal person's, or philosopher's criteria for a connected substrate in which holes may be formed.

In the title text, the theoretical physicist looks even deeper, at a subatomic level. Since fundamental particle interaction is governed by fundamental forces and collision instead of tensile or ductile solid connectedness, the theoretical physicist posits that any definition providing for a single hole would also describe a number of holes akin to the factorial of the number of particles in the universe, or at least within the cup's {{w|light cone}}, which is a number impractical to accurately count, but not uncountable in a mathematical sense.

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

:[The first panel has text only. The "Q:" below is a large letter Q representing a question, not a character name.]
:Q:
:How many holes are there in a coffee cup?

:[Each of the next four panels has a caption at the top to indicate the kind of person answering the question.]
:Caption: Topologist
:[Ponytail stands holding a coffee mug.]
:Ponytail: One.

:Caption: Normal person
:[Hairy stands to the right of Ponytail, holding a coffee mug at an angle to look into it.]
:Hairy: IDK, does the opening count as a hole?

:Caption: Philosopher
:[Hairbun is shown in closeup, with two drawings of coffee mugs to her left.]
:Hairbun: To answer that question, consider another: If we drill a hole in the side, how many holes are there now?

:Caption: Chemist
:[Cueball stands with a drawing of a caffeine molecule above him and to the right.]
:Cueball: 1021 in the caffeine alone

{{comic discussion}}
[[Category:Comics featuring Ponytail]]
[[Category:Comics featuring Hairy]]
[[Category:Comics featuring Hairbun]]
[[Category:Comics featuring Cueball]]
[[Category:Math]]
[[Category:Food]]
[[Category:Science]]
[[Category:Chemistry]]
[[Category:Philosophy]]

Talk:2655: Asking Scientists Questions

2022-08-06T08:37:52Z

Flukx: blag explanation wanted

I am of three minds. Part of me wants to write a basic explanation to get us started. Part of me is worried I'll lay a terrible foundation. And part of me doesn't want to get rid of "This is a comic about scientists.{{citation needed}}" without memorializing it first. [[User:GreatWyrmGold|GreatWyrmGold]] ([[User talk:GreatWyrmGold|talk]]) 22:12, 5 August 2022 (UTC)
:That was cute, but your relocated {{citation needed}} is a fine replacement. [[User:Barmar|Barmar]] ([[User talk:Barmar|talk]]) 22:37, 5 August 2022 (UTC)

Considering "tastes awful", I'm a chemist and know an old recipe for amalgam-related stuff, quote, "...the reaction is over when the stuff doesn't taste metallic anymore". mode=Homer "Mmmmh, mercury!" [[Special:Contributions/172.71.94.187|172.71.94.187]] 07:52, 6 August 2022 (UTC)

The first line of the explanation contains the word 'blag' in parenthesis. I don't know this word and the translations that dic.cc give are 'badly behaving child' and 'armed robbery' which don't make sense in this context. Can someone explain, please? [[User:Flukx|Flukx]] ([[User talk:Flukx|talk]]) 08:37, 6 August 2022 (UTC)