explain xkcd - User contributions [en]

Talk:2919: Sitting in a Tree

2024-04-13T20:04:38Z

108.162.241.170: comment

Meh, they're just dropping burning pine cones on the wargs. [[User:BunsenH|BunsenH]] ([[User talk:BunsenH|talk]]) 04:06, 13 April 2024 (UTC)

I hope I did this right, seeing as this was my first ever edit! [[User:Name of User|Name of User]] ([[User talk:Name of User|talk]]) 04:15, 13 April 2024 (UTC)

Did Randall mean e-filing as in submitting your tax return on the web, and how is that more alarming than ironing sitting on a branch? Or is there some other meaning to efiling?
:I assumed it was a reference to the tax filing deadline in the USA. [[Special:Contributions/162.158.154.207|162.158.154.207]] 14:15, 13 April 2024 (UTC)
[[Special:Contributions/172.68.243.77|172.68.243.77]] 06:46, 13 April 2024 (UTC)
:Could be that they're sitting in a ''data tree'', selectively traversing it to find [[2918: Tick Marks|a fraudulent subset of transactional records]] to 'declare'... [[Special:Contributions/141.101.99.74|141.101.99.74]] 10:18, 13 April 2024 (UTC)
To me it seems "efiling" could be supporting/enacting efilism? Definitely more disturbing.

So, "whaling" can mean hitting (usually in the form "whaling on"), but "whaling" also means spending a lot of money, such as when gambling or in a video game. {{unsigned ip|172.71.222.210|11:05, 13 April 2024}}
:Personally, I just automatically thought they would be ''actually'' hunting marine mammals![[[731: Desert Island|''cetacean]] [[1402: Harpoons|needed'']]] [[Special:Contributions/172.69.194.204|172.69.194.204]] 11:30, 13 April 2024 (UTC)
::Absolutely - in the hierarchy "what words mean", I'd say "what the word literally means" has a good argument for being at the top. "Whaling" ''also'' means "hitting", and even then, only phrasally: it's surely only ever "whaling on + object". "Whaling", in isolation, is hunting whales.[[User:Yorkshire Pudding|Yorkshire Pudding]] ([[User talk:Yorkshire Pudding|talk]]) 11:54, 13 April 2024 (UTC)
::I believe it only applies to Ishmael and Queequeg, I guess. They're quite homosexual. [[Special:Contributions/108.162.241.170|108.162.241.170]] 20:04, 13 April 2024 (UTC)

Do "perish/carriage" actually rhyme in (perhaps) the Bostonian accent? I'm drawn back to the state of the Edmund Fitzgerald lyrical rhyming scheme. It might work better using something like "pillage/carriage", with ''only'' the vowel-problem. At which point I could imagine it sort of working in a (bad) Kiwi or Africaans 'iccint'. [[Special:Contributions/172.69.195.121|172.69.195.121]] 11:42, 13 April 2024 (UTC)
:I think they come quite close in a "general" North American accent. The "pairish" and "cairidge" sounds, stretched out a little to fit the tune, sit well enough together.[[User:Yorkshire Pudding|Yorkshire Pudding]] ([[User talk:Yorkshire Pudding|talk]]) 11:48, 13 April 2024 (UTC)

I came here looking for explanations of "efiling", and I have to say "efilism", which I'd never heard of before, certainly sounds more in keeping with that frame than "e-filing", which just sounds tedious, even if the first result DuckDuckGo offers me is for [https://secure.sarsefiling.co.za/landing something called SARS] which [https://en.wikipedia.org/wiki/SARS seems an unfortunate name]. - [[User:IMSoP|IMSoP]] ([[User talk:IMSoP|talk]]) 13:31, 13 April 2024 (UTC)

2913: Periodic Table Regions

2024-03-30T22:10:02Z

108.162.241.170: Clarification that 'proton' hydrogen is specifically of the H-1 isotope

{{comic
| number = 2913
| date = March 29, 2024
| title = Periodic Table Regions
| image = periodic_table_regions_2x.png
| imagesize = 740x501px
| noexpand = true
| titletext = Cesium-133, let it be. Cesium-134, let it be even more.
}}

==Explanation==
{{incomplete|Created by a LAWFUL NEUTRAL MURDER WEAPON COMMONLY USED TO MAKE SPARK PLUGS' VOICES SQUEAKY- Please change this comment when editing this page. Do NOT delete this tag too soon.}}

The {{w|periodic table}} is used to arrange {{w|chemical element}}s based on their properties. This comic groups them together into regions with labels humorously reflecting their properties, characteristics, or uses.

=== Table Sections ===

{| class=wikitable
! scope="col" | Section
! scope="col" | Real table
! scope="col" | Elements contained
! scope="col" | Explanation
|-
| Slightly fancy protons || Hydrogen || Hydrogen || Most hydrogen atoms (specifically of the isotope H-1, making up 99.9844% of all hydrogen on Earth) are a proton and an electron. Since the electron can be removed (so only a proton remains) and you can call that a H+ ion, [[Randall]] calls hydrogen atoms "slightly fancy protons".
|-
| Weird dirt || Lighter alkali and alkaline earth metals || Lithium, Beryllium || Lithium and beryllium, as some of the lightest elements, have unusual properties compared to heavier metals. Lithium, for instance, is the least dense metal on the periodic table, and is used in applications such as [https://www.rsc.org/periodic-table/element/3/lithium rechargeable batteries]. Beryllium is both toxic and transparent to x-rays, but also keeps its shape and stiffness over a wide range of temperatures, leading to its use in the primary mirrors of the [https://webb.nasa.gov/content/observatory/ote/mirrors/index.html#3 James Webb Space Telescope].
|-
| Regular dirt || Middle alkali and alkaline earth metals || Sodium, Magnesium, Potassium, Calcium || Despite being metals, these are listed as "dirt" rather than "metal." Perhaps this is because they are commonly found in dirt, as they are essential nutrients for plant life and for many other forms of life, including humans).
|-
| Ends in a number, let it slumber. Ends in a letter, not much better. || Heavier alkali and alkaline earth metals || Rubidium, Strontium, Cesium, Barium, Francium, Radium || Highly reactive metals, some of which are commonly used as radioactive isotopes (which are known by a number; e.g. radium-223). The title text mentions cesium-133 and cesium-134, with the former being the only stable isotope of cesium. Cesium-134 however isn't the most notorious radioactive isotope. That would likely be cesium-137.
|-
| Boring alloy metals. Probably crucial to the spark plug industry or something. (But one of them is radioactive so stay on your toes.) || The left transition metals || Scandium, Titanium, Vanadium, Chromium, Manganese, Yttrium, Zirconium, Niobium, Molybdenum, Technetium, Ruthenium, Hafnium, Tantalum, Tungsten, Rhenium, Osmium || Not actually so boring, but they tend to be used as constituents (sometimes as a small but vital trace) in alloys with specific uses, including {{w|stainless steel}}, {{w|Electric light|bulb filaments}} and {{w|Superconductivity|superconductors}}. A {{w|spark plug}} may use {{w|austenitic stainless steel}}, which includes chromium and (in some cases) molybdenum, for heat and oxidation resistance. {{w|Technetium}} is the lightest element that has no stable isotope and is thus radioactive. Technetium is commonly used in medical imaging.
|-
| Regular metals || The top transition metals || Titanium, Manganese, Iron, Cobalt, Nickel, Copper, Zinc, Aluminum, Silicon || Commonly known metals (and one metalloid, silicon). These all have important uses in construction and other major industries.
|-
| $$$$ || The platinum group || Rhodium, Palladium, Silver, Osmium, Iridium, Platinum, Gold || Rare and highly prized metals.
|-
| Weird metals || The "ordinary metals" and some transition metals || Gallium, Germanium, Cadmium, Indium, Tin, Mercury || These are more obscure than the other metals (except tin and mercury) and tend to have fewer or more specialized uses. Mercury is also the only metal that is liquid at room temperature, and gallium melts just above that at 30 °C (86 °F).
|-
| Boron (fool's carbon) || Boron || Boron || Just as like how {{w|pyrite}} is commonly called "fool's gold", Randall calls {{w|boron}} "fool's carbon" due to its similarities in the way both elements can make stable {{w|covalently bonded}} molecules. Many of boron's {{w|allotropes}} are also analogous with those of carbon.
|-
| You are here || Nonmetals || Carbon, Nitrogen, Oxygen, Phosphorus || Other than hydrogen, these are all the elements required to make {{w|DNA}}, and they make up the majority of atoms in other biological molecules, thus placing you over here.
|-
| Murder weapons || Ordinary metals and metalloids || Arsenic, Antimony, Tellurium, Thallium, Lead, Bismuth, Polonium || Arsenic, thallium, lead, and polonium are highly toxic and have been involved in many notorious poisoning cases. Antimony and tellurium are also hazardous, though to a lesser degree. Bismuth is the odd one out, having little toxicity at all, but it is used in lead free bullets and shot.
|-
| Safety goggles required || The lighter halogens + some of group 16 || Fluorine, Sulfur, Chlorine, Selenium, Bromine || These elements are highly reactive, so safety goggles are required. Randall has previously mentioned the nasty properties of {{w|bromine}} at room temperature in [https://what-if.xkcd.com/50/ Extreme Boating].
|-
| Very specific health problems || Iodine and radon || Iodine, Radon || {{w|Radon}} gas is formed in the radioactive decay series of uranium and thorium, which occur in trace levels in many common minerals. The gravel and concrete used in construction include such minerals, and the radon is released into air via pores and cracks in the stone and concrete. The relatively poor ventilation in underground spaces such as basements and cellars can cause the radon to accumulate rather than being released into the environment. Eventually, the radon itself decays into other elements, which are also radioactive. Radon is chemically very inert and doesn't bind to anything, but it can still be inhaled, and its daughter elements can bind to dust particles. The radioactive materials, when inhaled, can cause damage to cells, especially in the lungs, with lung cancers as a possible long-term consequence. Iodine is a required nutrient that humans need in trace amounts to remain healthy, with an iodine deficiency typically causing thyroid problems such as goitre. Radioactive iodine is easily taken into the body, deliberately to counteract hyperthyroidism or uncontrollably due to exposure to material in nuclear fallout/accidents. Giving high doses of 'normal' iodine would ideally flush out the problematic isotope. Even comparing the two radioactive effects, these two specific health problems are entirely unrelated, and it is only by coincidence that they are corner-to-corner on the periodic table.
|-
| Lawful Neutral || Noble gases || Helium, Neon, Argon, Krypton, Xenon || These elements are mostly unreactive. (The first three don't form chemical compounds at all, apart from things like unstable ionic complexes. The other two do form a few compounds, but these are rather difficult to synthesize and are quite reactive.)
Lawful Neutral is a reference to the D&D alignment chart, which gives moral categories for characters. The chart goes from Lawful to Chaotic on one axis, and Good to Evil on another. Lawful Neutral means following the law without any bias towards Good or Evil, which could be exemplified by the unreactivity of the Noble Gases.
|-
| Don't bother learning their names – they're not staying long || Astatine and Period 7 from Rutherfordium onwards || Astatine, Rutherfordium, Dubnium, Seaborgium, Bohrium, Hassium, Meitnerium, Darmstadtium, Roentgenium, Copernicum, Nihonium, Flevorium, Moscovium, Livermorium, Tennessine, Oganesson || These elements are hard to produce in large quantities and decay within hours or less... in some cases, milliseconds. (Their names haven't exactly been stable, either, with previous multiple systems of placeholder names. For example, dubnium has been called nielsbohrium, hahnium, joliotium, unnilpentium, and eka-tantalum.)
|-
| Whoever figures out a better way to fit these up there gets the next Nobel Prize || The internal transition metals || Lanthanum, Cerium, Praseodymium, Neodymium, Promethium, Samarium, Europium, Gadolinium, Terbium, Dysprosium, Holmium, Erbium, Thulium, Ytterbium, Lutetium, Actinium, Thorium, Protactinium, Uranium, Neptunium, Plutonium, Americium, Curium, Berkelium, Californium, Einsteinium, Fermium, Mendelevium, Nobelium, Lawrencium|| The {{w|lanthanide}}s and {{w|actinide}}s are placed awkwardly "outside" of the main periodic table, taking two elements out of their own position (not all versions with separated rows do this); there are alternative {{w|types of periodic tables}} with differing ways of displaying the elements, however they are usually considered either less visually appealing or more difficult to understand.
|}

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

:[A periodic table with regions labeled. Regions are marked with shapes that have rounded edges and sometimes a chemical element can be partially in two regions.]

:[Hydrogen:]
:Slightly fancy protons
:[Lithium and beryllium:]
:Weird dirt
:[4 elements below:]
:Regular dirt
:[6 elements further below:]
:Ends in a number, let it slumber
:ends in a letter, not much better
:[Left side of the transition metals group:]
:Boring alloy metals
:Probably critical to the spark plug industry or something
:(but one of them is radioactive so stay on your toes)
:[Most of the top row of the transition metals + aluminum:]
:Regular metals
:[Below the rightmost "regular metals":]
:Weird metals
:[Between "boring alloy metals" and "weird metals":]
:$$$$
:[Boron:]
:Boron (fool's carbon)
:[Top-center of p-block:]
:You are here
:[Top-right of p-block, excluding the rightmost column:]
:Safety goggles required
:[5 uppermost elements of the rightmost column:]
:Lawful neutral
:[Iodine and radon:]
:Very specific health problems
:[Below and to the right of "weird metals":]
:Murder weapons
:[Bottom row from the fourth column onwards:]
:Don't bother learning their names - they're not staying long
:[The lanthanides and actinides below the rest of the table, two rows of fifteen elements, arrow pointing to a conspicuous gap in the third column of the main table where the fifteenth would ordinarily be:]
:Whoever figures out a better way to fit these up there gets the next Nobel Prize

{{comic discussion}}

[[Category:Chemistry]]

Talk:2880: Sheet Bend

2024-01-14T14:42:40Z

108.162.241.170: Added comment(s). Edited one grammar error.

Why is this called a "sheet" bend? [[User:SystemParadox|SystemParadox]] ([[User talk:SystemParadox|talk]]) 21:17, 12 January 2024 (UTC)
:I don't know the full answer but it's a sailing thing: the 'sheet' is the rope you pull in or let out to control the position of the sail. I guess bend describes the category of knot. [[Special:Contributions/172.70.90.48|172.70.90.48]] 21:23, 12 January 2024 (UTC)
::NO NO NO. The sheet is the sail. [[User:JohnB|JohnB]] ([[User talk:JohnB|talk]]) 21:36, 12 January 2024 (UTC)
:::It is the rope - {{w|Sheet (sailing)}}. "In sailing, a sheet is a line (rope, cable or chain) used to control the movable corner(s) (clews) of a sail." [[Special:Contributions/172.71.242.5|172.71.242.5]] 21:56, 12 January 2024 (UTC)
::::Huh. Dueling Wikipedia articles. The Sheet_bend article has a definition section that says the term "sheet bend" derives from its use bending ropes to sails (sheets). But the Sheet_(sailing) article says a sheet is a line used to control the movable corner(s) of a sail. [[User:JohnB|JohnB]] ([[User talk:JohnB|talk]]) 23:08, 12 January 2024 (UTC)
::The sheet bend is named for its ability to to secure a sail, or sheet. You fold over the corner of the sail and that's one of your "ropes". The sheet bend is generally used as a knot for tying a large, inflexible rope (or rope-like object) to a smaller, more flexible rope.[[Special:Contributions/172.69.70.22|172.69.70.22]] 22:30, 12 January 2024 (UTC)
::I would take the Ashley Book of Knots as authoritative. Sheet Bend is the first knot in the book, and is always (in modern terms) rope-to-rope, not to sail. It is one of the basic knots. https://en.wikipedia.org/wiki/The_Ashley_Book_of_Knots https://en.wikipedia.org/wiki/Sheet_bend
::{{unsigned|PRR|04:04, 13 January 2024}} 
:::But what dispute are you taking TABoK's authority on? Two things can have the same name in different contexts (or namespaces). And does Ashley use anything other than ropes exclusively in the whole book? [[Special:Contributions/108.162.241.170|108.162.241.170]] 14:42, 14 January 2024 (UTC)
:I added a link to the wikipedia entry, it explains the name. [[User:Barmar|Barmar]] ([[User talk:Barmar|talk]]) 21:25, 12 January 2024 (UTC)
:Presumably the "different loads" title text is a pun between electrical load and mechanical stress on the knot? [[User:Jim-at-home|Jim-at-home]] ([[User talk:Jim-at-home|talk]]) 21:56, 12 January 2024 (UTC)

A sail is never, and was never, properly called a "sheet", since at least the 13th century. The Wikipedia explanation of the name is misleading. According to https://www.etymonline.com/word/sheet, it's "shortened from Old English sceatline "sheet-line," from sceata "lower part of sail," originally "piece of cloth," from same Proto-Germanic source as sheet (n.1)." [[User:Jlearman|Jlearman]] ([[User talk:Jlearman|talk]]) 17:44, 13 January 2024 (UTC)
: When I took a sailing class as a kid they used the word “sheet”, I think it was the lines connected to the sails used for adjusting them? [[Special:Contributions/108.162.245.82|108.162.245.82]] 19:46, 13 January 2024 (UTC)

“silver being joined to silver and gold being joined to gold within the insulating white cable” is not the conventional way to join cables.
Unless you are joining one cable to itself (like a Möbius strip), you have ''two'' cables with insulation.
And usually you use non-cursed connectors, where you first remove the insulation at the end of the cable and then crimp or solder the conductors to metal parts of the connector; or solder the conductors and then add a different type of insulation for protection; or use screw terminals;...
Only with insulation displacement connectors you keep using all the insulation of the two cables.
And finally, conductors are usually copper ''or'' aluminum, and very rarely silver ''and'' gold. --[[Special:Contributions/162.158.94.141|162.158.94.141]] 08:45, 13 January 2024 (UTC)
:I think the gold and silver is just color coded for the reader. Not that they are meant to indicate that the conductors are made from this material. Apart from that you comment sounds like you know what you are talking about. So please improve the explanation if you can. --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 10:58, 13 January 2024 (UTC)

::: I changed it to gold- and silver-colored. It was obvious to me that it was the colours used in the comic that were being referenced, but fixed for the avoidance of doubt. The join being made within the one cable was clearly an error though. [[Special:Contributions/172.70.85.161|172.70.85.161]] 22:13, 13 January 2024 (UTC)

:: cables often have the signal parts copper-colored (described gold atm) and they are obviously copper, and the outer ground more the color of steel or something, not sure what metal it is, but it’s easy to solder like copper or silver is, not aluminum which is very hard to solder. usually gold and silver are used at the contacts of a connector, not inside a wire, i don’t know who would ever make that mistake. [[Special:Contributions/108.162.245.83|108.162.245.83]] 19:49, 13 January 2024 (UTC)
:::"''more the color of steel or something, not sure what metal it is, but it’s easy to solder like copper or silver''" Traditionally tinned copper. Tinned not just for identification, or easier soldering, but because early rubber insulation actively rotted copper and tinning slowed the damage. Many sorts of damage, why much copper today is silvery. [[User:PRR|PRR]] ([[User talk:PRR|talk]]) 04:16, 14 January 2024 (UTC)
::: Not wishing to spoil it, but the series finale of {{w|Cabin Pressure (radio series)|a certain radio comedy}} reveals... ah well, that's the spoiler (in the article, if you read that far down... rather than just listen to it if you haven't heard about it already but now think you like the premise). [[Special:Contributions/172.69.79.188|172.69.79.188]] 21:01, 13 January 2024 (UTC)

Okay I looked at the wikipedia article and the knot depicted in the comic looks like a right handed one. I still don't know why it's called right handed, or why the left handed one is insecure.[[Special:Contributions/198.41.236.207|198.41.236.207]] 11:46, 13 January 2024 (UTC)

A note I nearly added in the bit about short-circuits (or, as I added, 'un'circuiting) is that the electrical behaviour of the knot is different according to which 'end' slips. If the left-side cable 'slips through' enough, then its gold and silver bits of sheath could contact (would short-circuit any current driven at that side). If the right-side cable slips out, it is in no danger of doing so for a right-driven current (it would just disconnect). That ignores the cross-talking that could occur (on one conducting line at a time, so may not matter if there's no external ground-return element, except as far as not being a proper connection any more), or ''both'' ends slipping (where one of the LHS sheaths ''might'' shuffle into a position to bridge the two RHS sheaths). But, as tied, the LHS silver (being bent in and out of the page around its crossing counterpart wire) seems unlikely to be pressed against both gold and silver, should it trivially untwine/slip through. Actual studies with actual knots might be useful. I thought I had a spare length of unterminated Cat5, nearby, but apparently (k)not... that, with some coloured permanent marker-pen marks made upon it, would probably have made a decent analogue for visual analysis of failure conditions. Maybe I'll de-plug an old cable (I've got a number of damaged USB cables I could chop, but their being thinner would change the scale and dynamics of the knot, meaning I might as well just use a scrap of twisted-pair internally-sheathed strands). – But I thought you'd like my mind's-eye analysis of the knot behaviour, before I get around to trying anything practical to this end. [[Special:Contributions/141.101.99.7|141.101.99.7]] 17:08, 13 January 2024 (UTC) (<- ex Cub-/Boy-/Venture-Scout, but never got any Knot ''Un''tying badge... that brief stint with escapology aside... ;) )

This comic contained material familiar to a hobby engineer that was cast critically and derogatorily (e.g. “sheety” bend) throughout the explanation. I edited a lot of it. I’ve seen this happen repeatedly in other explanations. I don’t edit most of them. [[Special:Contributions/172.71.150.155|172.71.150.155]] 18:41, 13 January 2024 (UTC) 

"this is a scenario commonly encountered by hobby engineers from the last millenium"
"commonly"? Can any hobbyist engineers from the last millennium attest? Also, this sounds ageist - is it ageist? [[Special:Contributions/172.70.86.166|172.70.86.166]] 21:56, 13 January 2024 (UTC)
:Well, I definitely did electrics/electronics pre-millenium. I'm not at all unhappy with the idea with the possibility of an occasional 'bodge job' connection having happened (e.g. tying a cable in a simple knot, in suitable cases, to add mechanical resistance to any further tendency for a cable to be tugged out of a grommit-hole and the core conducting wires being tugged out of whatever terminal/patch-block they need to be connected to - or, more likely, pulling the core copper strands beyond their tensile limits).
:Although (while I respected the ''idea'' of this being based upon a repair-bodge), I don't see this as a "this wire was damaged, this is how the two ends are reconnected", but rather as a deliberate cable termination method (like adding moulded plugs/etc) which could then be mated end-to-end with another similarly terminated cable. (Like using a gender-changer 'double-socket' between two phono-ended lengths of cable, or using a {{w|File:BNC Tee connector, with Ethernet cable connected-92166.jpg|BNC T-connector just to join two lengths of networking cable}} but without the need for the extra connector ''and'' adding intrinsic tensile resistance - though actually not as much as the BNC 'bayonet' version already does...)
:If I was writing this from scratch, I'd actually remove all the 'repair' aspect of it, TBH. It looks more like a deliberate patch-type cable (1x2core) manufactured to be directly and hermaphroditically compatible with any other such cable, tied together without the need for tools (screwdrivers, crimpers, punch-downs, etc) ''and'' untied as and when required (at least as easily as any similar rope-knot can be undone, which isn't always a given if mishandled and overtightened).
:I'd also be looking at various knots and working out which (if any) could support ''more'' than two contact-patches/sleavings per cable, for three-core or more-core connections between any two such cables. The geometry of the knots would define roughly where (and how long) the external contact-sleaves would need to be (presumably identical for both cables) such that they made appropriate connections between the two halves (cross-overs could be allowed, but that'd have to be down to the IEEE specifications of how to detect/interpret RX/TX assymetry at the end devices, etc). But then I'd also be writing a vastly more complicated alternate explanation. Perhaps just remove the bodge-job implications, someone? Clearly it's not an end-user bodge. Though it could be a manufacturer/industry bodge (such as using an 8P8C connector for essentially 6P4C purposes). [[Special:Contributions/172.69.79.138|172.69.79.138]] 00:53, 14 January 2024 (UTC)
I use the reader app in inverted color mode, so I could not for the life of me figure out what all the discussion about silver and gold was about. Also, can I just comment on how the conductive sleeves are magically flexible? I wonder if they are braided. Even then, this would severely limit how tight the knot could be pulled. [[Special:Contributions/162.158.154.238|162.158.154.238]] 13:26, 14 January 2024 (UTC)

2755: Effect Size

2024-01-12T17:18:21Z

108.162.241.170: /* Explanation */ change to template

{{comic
| number = 2755
| date = March 27, 2023
| title = Effect Size
| image = effect_size_2x.png
| imagesize = 278x366px
| noexpand = true
| titletext = Subgroup analysis is ongoing.
}}

==Explanation==
This comic outlines a {{w|meta-analysis}}, or more aptly THE meta-analysis, as its inclusion criteria are simply all studies.

A meta-analysis, true to its name, is a statistical analysis of statistical analyses, usually those attempting to answer a single question. Meta-analyses are intended to account for possible individual error within each study, summarizing the general results of all of its studies in order to potentially draw a useful conclusion. For a meta-analysis to be possible, there must be some measured variable in common across the included studies.

Here, the meta-analysis consists of a graph of {{w|effect sizes}} for what is allegedly every single study ever conducted. Accordingly, even page 53,589 of the meta-analysis is only about 1/4 of the total graph, as the scroll bar on the right is only about 1/4 of the way down; this makes the total included in the meta-analysis approximately 210,000 pages, or around 2.3 million studies. Below the graph is an estimate of the "average effect" across all of these variables, the effect normally being the relationship being analyzed by the studies within a meta-analysis, though here it seems again to be just a conglomerate of all known effects, along with a (likely) 95% {{w|confidence interval}} for the findings of the meta-analysis. It's absurd to analyze all studies this way, as the variables that all of those studies measure are wildly different and it makes no sense whatsoever to average (or otherwise analyze) them together. In addition, 2.3 million scientific studies is much too small a number; a [https://www.stm-assoc.org/about-stm/ recent estimate] is that about 3 million papers are published ''each year'', and while not all of them would have a numerical hypothesis test, many others would have several such tests.

Statistical studies are produced by generating hypotheses and then testing those hypotheses. A meta-analysis of all studies would therefore include both studies where the original hypothesis turns out to be false, as well as studies where the original hypothesis is confirmed. Hypotheses that fail to be confirmed by studies are often discarded; however, these studies would still be included in this meta-analysis.

In the caption, Randall delivers the bad news: that the meta-analysis of "all of science" has finally been performed, and as it turns out, the results are not significant. {{w|Statistical significance}} is the degree to which the results of a sample or study are likely due to a correlation, as opposed to chance or {{w|sampling variation}} alone. Apparently, across the entirety of human science in the study of our universe, the study has found a lack of significance, or of a relationship between all the variables measured by all the studies ever.

The joke lies in the absurdity of the claim that "all of science" can be analyzed at all. Science is not a singular term that can be subcategorized in such a manner, but is rather hundreds of different fields of study, many of which have little or no overlap. Doing a meta-analysis of geology and philosophy, for example, would be patently ridiculous, so the 53,589 (or 210,000) page study is comical in its very existence, much less conclusion. In addition the comic conflates two meanings of "significant": the statistical meaning, and the more everyday meaning of importance or noteworthiness.

Additionally to the absurdity, one can see the whole joke as an instance of the {{w|Liar paradox}}: if one considers that the conclusion of the meta-analysis is that "science" is statistically unable to provide information on the truth of a statement, then the meta-analysis itself (in it has been made following the general principles of rigor and methods of "science") is subject to its conclusion. Hence, the conclusion of the meta-analysis might have nothing to do with the truth, and "science" might well be significant after all. But if it is, then the present meta-analysis should be considered significant as well and one should believe its conclusion, etc.

In the title text, Randall reports that {{w|subgroup analysis}} is ongoing. The joke here is that since all scientific studies are subsets of the overall meta-analysis, every field of scientific endeavor can be separately assessed by constraining the subgroup to include only studies in that field. Hence the subgroup analysis could be considered to include analyses of every individual area or question that scientists have made subject to statistical studies. Again, analyzing any subgroup would lump together studies that measured very different things and hence would still be meaningless.

XKCD has previously considered the topic of subgroup analyses around the important issue of [[882|jelly beans]]. Subgroup analyses may be used as {{w|data dredging}} or [[1478|p-hacking]] in order to identify anything that is "significant" and thus publishable.

==Transcript==
:Meta-analysis
:Inclusion criteria: All studies

:[A forest plot is shown. In the tab on the top right, there is a label "Page 53,589". On the right side of the plot, there is a vertical scrollbar where the scroll box is about one quarter from the top. A horizontal axis centered on 0 is shown at the bottom and -1 and +1 on either side are labeled. In the middle of the plot, there is a dashed vertical line. On both sides of the vertical line in separate rows, there are black boxes of different sizes with horizontal bars of varying lengths on the sides of the boxes. Below the plot, slightly to the right of the vertical line, there is a black diamond wider than it is tall, labeled "0.17 (-0.14, 0.52)".]

:[Caption below the panel:]
:Bad news: They finally did a meta-analysis of all science, and it turns out it's not significant.

{{comic discussion}}

[[Category:Statistics]]
[[Category:Science]]

55: Useless

2024-01-04T02:10:55Z

108.162.241.170: trim

{{comic
| number = 55
| date = January 27, 2006
| title = Useless
| before = <big><big>[https://web.archive.org/web/20060529063441/http://xkcd-drawings.livejournal.com/#:~:text=4%3A38%20am-,Useless,-(3%20Comments LiveJournal title]: '''Useless'''</big></big>
| image = useless.jpg
| titletext = Even the identity matrix doesn't work normally
}}

==Explanation==
This was the fifty-second and last comic originally posted to [[LiveJournal]]. The previous one was [[53: Hobby]], but the next comic, [[56: The Cure]], was never posted to LiveJournal. It was among the [[:Category:Posted on LiveJournal after xkcd.com|last eleven comics]] posted both on LiveJournal and on [https://xkcd.com xkcd.com] after the new site was launched. This comic was published on the same day across both sites, but not all of them shared the same posting day.

[[Randall Munroe|Randall]] is attempting to apply mathematics to the concept of love to no avail. Specifically, he is attempting his "normal approach", which is a term used in mathematics for the method one typically uses to solve a certain type of problem. However, as love is not a well-defined mathematical entity, his normal approach is useless. Simply put: he's saying he has found no way of describing love using only the tools of mathematics.

From the top, moving left to right, he tries the {{w|square root}} of love, the {{w|cosine}} of love, and the {{w|derivative}} of love with respect to x. He then attempts to left-multiply love by a 2x2 {{w|identity matrix}}, and finally he defines a {{w|Function (mathematics)|function}} of love as a {{w|Fourier transform}}. These are all "normal approaches" to solving certain math problems. The message of the comic is that for someone who uses math to solve all their problems, defining love is impossible. It also indicates that love is not always a rational (or irrational) phenomenon.

===Basic explanations of the functions===
* The {{w|square root}}s of x are the two numbers (positive and negative) where each multiplied by itself equals x. Often only the positive answer is quoted.
* {{w|Cosine}} is a {{w|trigonometric function}} that, when given the measure of an angle in a {{w|right triangle}} as an input, outputs the ratio of the lengths of two sides of that triangle (for cosine, it is the non-{{w|hypotenuse}} side adjacent to the angle and the hypotenuse).
* A {{w|derivative}} of a function is the rate of change of that function at a given value of x. It is a primary focus of {{w|calculus}}. A basic example is where "velocity" is the rate of change of displacement at a given time, the derivative of velocity is "acceleration", which is the rate of change of velocity at a given time.
* {{w|identity matrix|Identity matrices}} are {{w|matrix (mathematics)|matrices}} that consist of only zeros and ones, with zeros everywhere except along the {{w|main diagonal}}. Multiplying a matrix by the equal-sized identity matrix will result in the same output in the same way that multiplying a non-matrix by 1 does not change the original term. The title text suggests that multiplying love by the identity matrix does not return the same "love" value.
* A {{w|Fourier transform}} converts a function from one (sophisticated) function into an endless continuous series of simpler functions, where each next part is bringing the equation closer to the real result. This means that you can stop your calculations after a few iterations and you are very close to the real result, and it also can be used to deconstruct signals.

==Transcript==
:[Different mathematical equations, all with a heart on left side, and all ending up with question marks.]
:√♥ = ?
:cos ♥ = ?
:d/dx ♥ = ?
:[1 0]♥ = ?
:[0 1]
:F{♥} = 1/√2π ∫∞-∞f(t)eit♥dt = ?
:[Caption below the equations:]
:My normal approach is useless here.

==Trivia==
* In the book ''[[xkcd: volume 0]]'', this comic is slightly different. The derivative is with respect to time (''t'') instead of ''x'', and the function at the bottom is a {{w|Laplace transform}} instead of the bottom integral.
* Also in the book, a cipher is displayed prominently below the comic:

<pre>
CY-O CMLROOCXN. YR M.AOGP. NRK.W ABE ,CYDRGY M.AOGP.M.BY YD.P. JAB X. BR OJC.BJ.V <D.B CY JRM.O YR NRK.W ,.-P. ANN CB YD. EAPTV [[TCBO.F
</pre>

:This is a Dvorak to Qwerty cipher. Undeciphered, it reads:

::it"s impossiblE to mEasurE lovE, and Without mEasurEmEnt thErE can bE no sciEncE. whEn it comEs to lovE, WE"rE all in thE dark. __kinsEy
::: It's impossible to measure love, and without measurement there can be no science. When it comes to love, we're all in the dark. --{{w|Kinsey_(movie)|Kinsey}}

* The modified book version used to be [https://web.archive.org/web/20211215085605/https://store.xkcd.com/products/useless available as a T-shirt] in the xkcd store before it was [[Store|shut down]].
* This used to be one of the [[Footer comics|footer comics]] featured in the bottom segment of [https://xkcd.com xkcd.com].

{{comic discussion}}

[[Category:Posted on LiveJournal| 52]]
[[Category:Posted on LiveJournal after xkcd.com]]
[[Category:Romance]]
[[Category:Math]]
[[Category:Footer comics]] 
[[Category:Comics with xkcd store products]]
[[Category:Comics with lowercase text]]

xkcd: volume 0

2024-01-03T17:38:58Z

108.162.241.170: /* Transcript */

[[File:xkcd_volume_0.jpeg|260px|right|thumb|The cover of the book]]
{{notice|'''This explanation may be incomplete or incorrect:''' The article is missing more information and links about the book. If you can address this issue, please '''[{{fullurl:{{{target|{{FULLPAGENAME}}}}}|action=edit}} edit the page]!''' Thanks.}}

{{Quote|<nowiki></nowiki>''xkcd: volume 0'' is the first xkcd book! It features selections from the first 600 comics, including various author and fan favorites. It was lovingly assembled from high-resolution original scans of the comics (the mouseover text is discreetly included), and features a lot of doodles, notes, and puzzles in the margins.
|''[[Randall Munroe]]|[https://web.archive.org/web/20100701115034/http://store.xkcd.com/ Source]}}

'''''xkcd: volume 0''''' is a book by [[Randall Munroe]] released on August 24, 2010. It features a collection of comics personally chosen by the artist from the initial 600 entries of the webcomic. These comics were assembled from high-resolution original scans and include the original or, sometimes, a different title text. The book is available to [https://archive.org/details/2009Xkcd read in full on the Internet Archive].

The book is published by {{w|Breadpig}}, a company founded by Randall's friend Alexis, and their portion of the profits will go to build a school in Laos through the charity {{w|Room to Read}}.

==Included comics==
* [[10: Pi Equals]]
* [[242: The Difference]]
* [[249: Chess Photo]]
* [[123: Centrifugal Force]]
* [[214: The Problem with Wikipedia]]
* [[221: Random Number]]
* [[231: Cat Proximity]]
* [[20: Ferret]]
* [[21: Kepler]]
* [[30: Donner]]
* [[37: Hyphen]]
* [[82: Frame]]
* [[44: Love]]
* [[54: Science]]
* [[55: Useless]]
* [[85: Paths]]
* [[105: Parallel Universe]]
* [[108: M.C. Hammer Slide]]
* [[112: Baring My Heart]]
* [[114: Computational Linguists]]
* [[120: Dating Service]]
* [[116: City]]
* [[117: Pong]]
* [[124: Blogofractal]]
* [[128: dPain over dt]]
* [[134: Myspace]]
* [[135: Substitute]]
* [[136: Science Fair]]
* [[137: Dreams]]
* [[138: Pointers]]
* [[149: Sandwich]]
* [[152: Hamster Ball]]
* [[160: Penny Arcade Parody]]
* [[153: Cryptography]]
* [[159: Boombox]]
* [[157: Filler Art]]
* [[161: Accident]]
* [[162: Angular Momentum]]
* [[184: Matrix Transform]]
* [[163: Donald Knuth]]
* [[165: Turn Signals]]
* [[201: Christmas GPS]]
* [[177: Alice and Bob]]
* [[173: Movie Seating]]
* [[179: e to the pi times i]]
* [[191: Lojban]]
* [[210: 90's Flowchart]]
* [[200: Bill Nye]]
* [[182: Nash]]
* [[180: Canada]]
* [[215: Letting Go]]
* [[239: Blagofaire]]
* [[225: Open Source]]
* [[230: Hamiltonian]]
* [[240: Dream Girl]]
* [[247: Factoring the Time]]
* [[248: Hypotheticals]]
* [[253: Highway Engineer Pranks]]
* [[257: Code Talkers]]
* [[258: Conspiracy Theories]]
* [[262: IN UR REALITY]]
* [[276: Fixed Width]]
* [[274: With Apologies to The Who]]
* [[279: Pickup Lines]]
* [[275: Thoughts]]
* [[77: Bored with the Internet]]
* [[150: Grownups]]
* [[167: Nihilism]]
* [[144: Parody Week: A Softer World]]
* [[209: Kayak]]
* [[202: YouTube]]
* [[285: Wikipedian Protester]]
* [[472: House of Pancakes]]
* [[556: Alternative Energy Revolution]]
* [[442: xkcd Loves the Discovery Channel]]
* [[264: Choices: Part 1]]
* [[265: Choices: Part 2]]
* [[266: Choices: Part 3]]
* [[267: Choices: Part 4]]
* [[268: Choices: Part 5]]
* [[282: Organic Fuel]]
* [[280: Librarians]]
* [[320: 28-Hour Day]]
* [[316: Loud Sex]]
* [[284: Tape Measure]]
* [[287: NP-Complete]]
* [[290: Fucking Blue Shells]]
* [[303: Compiling]]
* [[291: Dignified]]
* [[305: Rule 34]]
* [[327: Exploits of a Mom]]
* [[333: Getting Out of Hand]]
* [[323: Ballmer Peak]]
* [[322: Pix Plz]]
* [[325: A-Minus-Minus]]
* [[340: Fight]]
* [[356: Nerd Sniping]]
* [[349: Success]]
* [[366: Your Mom]]
* [[369: Dangers]]
* [[372: To Be Wanted]]
* [[374: Journal]]
* [[377: Journal 2]]
* [[373: The Data So Far]]
* [[376: Bug]]
* [[380: Emoticon]]
* [[387: Advanced Technology]]
* [[386: Duty Calls]]
* [[412: Startled]]
* [[389: Keeping Time]]
* [[397: Unscientific]]
* [[391: Anti-Mindvirus]]
* [[393: Ultimate Game]]
* [[416: Zealous Autoconfig]]
* [[396: The Ring]]
* [[398: Tap That Ass]]
* [[420: Jealousy]]
* [[429: Fantasy]]
* [[434: xkcd Goes to the Airport]]
* [[435: Purity]]
* [[445: I Am Not Good with Boomerangs]]
* [[475: Further Boomerang Difficulties]]
* [[451: Impostor]]
* [[452: Mission]]
* [[463: Voting Machines]]
* [[500: Election]]
* [[481: Listen to Yourself]]
* [[486: I am Not a Ninja]]
* [[487: Numerical Sex Positions]]
* [[505: A Bunch of Rocks]]
* [[488: Steal This Comic]]
* [[511: Sleet]]
* [[530: I'm An Idiot]]
* [[513: Friends]]
* [[518: Flow Charts]]
* [[540: Base System]]
* [[569: Borders]]
* [[565: Security Question]]
* [[552: Correlation]]
* [[559: No Pun Intended]]
* [[591: Troll Slayer]]
* [[571: Can't Sleep]]
* [[592: Drama]]
* [[585: Outreach]]



==Transcript==
{{Incomplete transcript}}
===Front cover===
===Back cover===
:[There are several otherwise nondescript gray rectangles on which the characters stand on. Red spiders are present throughout the panel.]
:[Two of these rectangles are attached from above and going off of the cover, in an L-shape. Black Hat stands on it, taking notes on a journal. Twenty-three red spiders lie on the object. Nine of them are clustered in the inner L corner, four of them forming chains. An additional red spider has just fallen off of the object from the right.]



[[Category:Red Spiders]]
[[Category:Problematic pages]]
[[Category:Books]]
{{xkcdmeta}}

xkcd: volume 0

2024-01-03T17:37:59Z

108.162.241.170: Transcript of back cover (partial)

[[File:xkcd_volume_0.jpeg|260px|right|thumb|The cover of the book]]
{{notice|'''This explanation may be incomplete or incorrect:''' The article is missing more information and links about the book. If you can address this issue, please '''[{{fullurl:{{{target|{{FULLPAGENAME}}}}}|action=edit}} edit the page]!''' Thanks.}}

{{Quote|<nowiki></nowiki>''xkcd: volume 0'' is the first xkcd book! It features selections from the first 600 comics, including various author and fan favorites. It was lovingly assembled from high-resolution original scans of the comics (the mouseover text is discreetly included), and features a lot of doodles, notes, and puzzles in the margins.
|''[[Randall Munroe]]|[https://web.archive.org/web/20100701115034/http://store.xkcd.com/ Source]}}

'''''xkcd: volume 0''''' is a book by [[Randall Munroe]] released on August 24, 2010. It features a collection of comics personally chosen by the artist from the initial 600 entries of the webcomic. These comics were assembled from high-resolution original scans and include the original or, sometimes, a different title text. The book is available to [https://archive.org/details/2009Xkcd read in full on the Internet Archive].

The book is published by {{w|Breadpig}}, a company founded by Randall's friend Alexis, and their portion of the profits will go to build a school in Laos through the charity {{w|Room to Read}}.

==Included comics==
* [[10: Pi Equals]]
* [[242: The Difference]]
* [[249: Chess Photo]]
* [[123: Centrifugal Force]]
* [[214: The Problem with Wikipedia]]
* [[221: Random Number]]
* [[231: Cat Proximity]]
* [[20: Ferret]]
* [[21: Kepler]]
* [[30: Donner]]
* [[37: Hyphen]]
* [[82: Frame]]
* [[44: Love]]
* [[54: Science]]
* [[55: Useless]]
* [[85: Paths]]
* [[105: Parallel Universe]]
* [[108: M.C. Hammer Slide]]
* [[112: Baring My Heart]]
* [[114: Computational Linguists]]
* [[120: Dating Service]]
* [[116: City]]
* [[117: Pong]]
* [[124: Blogofractal]]
* [[128: dPain over dt]]
* [[134: Myspace]]
* [[135: Substitute]]
* [[136: Science Fair]]
* [[137: Dreams]]
* [[138: Pointers]]
* [[149: Sandwich]]
* [[152: Hamster Ball]]
* [[160: Penny Arcade Parody]]
* [[153: Cryptography]]
* [[159: Boombox]]
* [[157: Filler Art]]
* [[161: Accident]]
* [[162: Angular Momentum]]
* [[184: Matrix Transform]]
* [[163: Donald Knuth]]
* [[165: Turn Signals]]
* [[201: Christmas GPS]]
* [[177: Alice and Bob]]
* [[173: Movie Seating]]
* [[179: e to the pi times i]]
* [[191: Lojban]]
* [[210: 90's Flowchart]]
* [[200: Bill Nye]]
* [[182: Nash]]
* [[180: Canada]]
* [[215: Letting Go]]
* [[239: Blagofaire]]
* [[225: Open Source]]
* [[230: Hamiltonian]]
* [[240: Dream Girl]]
* [[247: Factoring the Time]]
* [[248: Hypotheticals]]
* [[253: Highway Engineer Pranks]]
* [[257: Code Talkers]]
* [[258: Conspiracy Theories]]
* [[262: IN UR REALITY]]
* [[276: Fixed Width]]
* [[274: With Apologies to The Who]]
* [[279: Pickup Lines]]
* [[275: Thoughts]]
* [[77: Bored with the Internet]]
* [[150: Grownups]]
* [[167: Nihilism]]
* [[144: Parody Week: A Softer World]]
* [[209: Kayak]]
* [[202: YouTube]]
* [[285: Wikipedian Protester]]
* [[472: House of Pancakes]]
* [[556: Alternative Energy Revolution]]
* [[442: xkcd Loves the Discovery Channel]]
* [[264: Choices: Part 1]]
* [[265: Choices: Part 2]]
* [[266: Choices: Part 3]]
* [[267: Choices: Part 4]]
* [[268: Choices: Part 5]]
* [[282: Organic Fuel]]
* [[280: Librarians]]
* [[320: 28-Hour Day]]
* [[316: Loud Sex]]
* [[284: Tape Measure]]
* [[287: NP-Complete]]
* [[290: Fucking Blue Shells]]
* [[303: Compiling]]
* [[291: Dignified]]
* [[305: Rule 34]]
* [[327: Exploits of a Mom]]
* [[333: Getting Out of Hand]]
* [[323: Ballmer Peak]]
* [[322: Pix Plz]]
* [[325: A-Minus-Minus]]
* [[340: Fight]]
* [[356: Nerd Sniping]]
* [[349: Success]]
* [[366: Your Mom]]
* [[369: Dangers]]
* [[372: To Be Wanted]]
* [[374: Journal]]
* [[377: Journal 2]]
* [[373: The Data So Far]]
* [[376: Bug]]
* [[380: Emoticon]]
* [[387: Advanced Technology]]
* [[386: Duty Calls]]
* [[412: Startled]]
* [[389: Keeping Time]]
* [[397: Unscientific]]
* [[391: Anti-Mindvirus]]
* [[393: Ultimate Game]]
* [[416: Zealous Autoconfig]]
* [[396: The Ring]]
* [[398: Tap That Ass]]
* [[420: Jealousy]]
* [[429: Fantasy]]
* [[434: xkcd Goes to the Airport]]
* [[435: Purity]]
* [[445: I Am Not Good with Boomerangs]]
* [[475: Further Boomerang Difficulties]]
* [[451: Impostor]]
* [[452: Mission]]
* [[463: Voting Machines]]
* [[500: Election]]
* [[481: Listen to Yourself]]
* [[486: I am Not a Ninja]]
* [[487: Numerical Sex Positions]]
* [[505: A Bunch of Rocks]]
* [[488: Steal This Comic]]
* [[511: Sleet]]
* [[530: I'm An Idiot]]
* [[513: Friends]]
* [[518: Flow Charts]]
* [[540: Base System]]
* [[569: Borders]]
* [[565: Security Question]]
* [[552: Correlation]]
* [[559: No Pun Intended]]
* [[591: Troll Slayer]]
* [[571: Can't Sleep]]
* [[592: Drama]]
* [[585: Outreach]]



==Transcript==
{{Incomplete transcript}}
===Front cover===
===Back cover===
:[There are several otherwise nondescript gray rectangles on which the characters stand on. Red spiders are present throughout the panel.]
:[Two of these rectangles are attached from above and going off of the cover, in an L-shape. Black Hat stands on it, taking notes on a journal. Twenty-three red spiders lie on the object. Nine of them are clustered in the inner L corner, four of them forming chains. An additional red spider has just fallen off of the object from the right.]



[[Category:Red spiders]]
[[Category:Problematic pages]]
[[Category:Books]]
{{xkcdmeta}}

2869: Puzzles

2023-12-18T22:55:21Z

108.162.241.170: /* Transcript */ extraneous space

{{comic
| number = 2869
| date = December 18, 2023
| title = Puzzles
| image = puzzles_2x.png
| imagesize = 328x455px
| noexpand = true
| titletext = Why couldn't the amulet have been hidden by Aunt Alice, who understands modern key exchange algorithms?
}}

==Explanation==
{{incomplete|Created by AUNT '''A'''MY, AS IN AN '''A'''WFUL CLUE FROM A CHILDREN'S BOOK - Please change this comment when editing this page. Do NOT delete this tag too soon.}}



The comic explains that some of the books that Randall read as a kid had horrible puzzles. It lists a (fake?) example about Aunt Gertrude's amulet, which the characters guess is hidden in the Ground because that starts with a G, like Gertrude, and that they should diG a hole. These guesses are unreasonable unless the answer is already known. (It is supposedly not already known by the characters.) There are several other unrelated words that begin with G, such as Gulf, or Gull, or Go-Get-a-plane-and-fly-to-Greenland.

The title text references {{w|Alice and Bob|Alice}}, a fictional character commonly used in discussions about cryptography. In those discussions, Alice is often sending and receiving encrypted messages, and she would be expected to be able to make a better puzzle than the one shown in the comic. Alice and Bob and other characters from the same set have been mentioned previously in xkcd, like in [[177: Alice and Bob]]. Using modern cryptography in lieu of riddles in children's stories was also mentioned in [[370: Redwall]].

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
:[Hairy, Jill, Ponytail, and Cueball, listed from left to right, are standing in a line. Hairy is in a thinking pose, Jill faces Hairy, and Ponytail and Cueball are walking to the right; Cueball is pointing off-panel.]
:Hairy: Aunt Gertrude must have left a clue to the amulet's location.
:Jill: Hmm. Wait a minute.
:Jill: '''G'''ertrude. '''G'''.
:Hairy: As in "'''G'''round!"
:Jill: And "di'''G''' a hole!"
:Ponytail: I'll get a shovel!
:Cueball: To the yard!

:[Caption below the panel:]
:Some of the authors of books I read as a kid were '''''terrible''''' at designing puzzles.

{{comic discussion}}

[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Hairy]]
[[Category:Comics featuring Jill]]
[[Category:Comics featuring Ponytail]]
[[Category:Cryptography]]
[[Category:Kids]]

2869: Puzzles

2023-12-18T22:54:49Z

108.162.241.170: /* Transcript */

{{comic
| number = 2869
| date = December 18, 2023
| title = Puzzles
| image = puzzles_2x.png
| imagesize = 328x455px
| noexpand = true
| titletext = Why couldn't the amulet have been hidden by Aunt Alice, who understands modern key exchange algorithms?
}}

==Explanation==
{{incomplete|Created by AUNT '''A'''MY, AS IN AN '''A'''WFUL CLUE FROM A CHILDREN'S BOOK - Please change this comment when editing this page. Do NOT delete this tag too soon.}}



The comic explains that some of the books that Randall read as a kid had horrible puzzles. It lists a (fake?) example about Aunt Gertrude's amulet, which the characters guess is hidden in the Ground because that starts with a G, like Gertrude, and that they should diG a hole. These guesses are unreasonable unless the answer is already known. (It is supposedly not already known by the characters.) There are several other unrelated words that begin with G, such as Gulf, or Gull, or Go-Get-a-plane-and-fly-to-Greenland.

The title text references {{w|Alice and Bob|Alice}}, a fictional character commonly used in discussions about cryptography. In those discussions, Alice is often sending and receiving encrypted messages, and she would be expected to be able to make a better puzzle than the one shown in the comic. Alice and Bob and other characters from the same set have been mentioned previously in xkcd, like in [[177: Alice and Bob]]. Using modern cryptography in lieu of riddles in children's stories was also mentioned in [[370: Redwall]].

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
:[Hairy, Jill, Ponytail, and Cueball , listed from left to right, are standing in a line. Hairy is in a thinking pose, Jill faces Hairy, and Ponytail and Cueball are walking to the right; Cueball is pointing off-panel.]
:Hairy: Aunt Gertrude must have left a clue to the amulet's location.
:Jill: Hmm. Wait a minute.
:Jill: '''G'''ertrude. '''G'''.
:Hairy: As in "'''G'''round!"
:Jill: And "di'''G''' a hole!"
:Ponytail: I'll get a shovel!
:Cueball: To the yard!

:[Caption below the panel:]
:Some of the authors of books I read as a kid were '''''terrible''''' at designing puzzles.

{{comic discussion}}

[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Hairy]]
[[Category:Comics featuring Jill]]
[[Category:Comics featuring Ponytail]]
[[Category:Cryptography]]
[[Category:Kids]]

2856: Materials Scientists

2023-11-23T20:04:55Z

108.162.241.170: trivia

{{comic
| number = 2856
| date = November 17, 2023
| title = Materials Scientists
| image = materials_scientists_2x.png
| imagesize = 296x445px
| noexpand = true
| titletext = If a materials scientist gives you a present, always ask whether regifting will incur any requirements for Federal paperwork.
}}

==Explanation==
{{incomplete|Created by a BIOLUMINESCENT DEPLETED URANIUM WRAPPING PAPER GIVING OFF A BIT TOO MUCH CHERENKOV RADIATION- Please change this comment when editing this page. Do NOT delete this tag too soon.}}

{{w|Materials science}} is essentially the study of materials, like {{w|steel}}, including some pretty strange ones such as {{w|Vantablack}} and {{w|triiodide}}. Here Ponytail and White Hat have given Cueball (a materials scientist) some sort of present. Cueball is amazed with the wrapping paper and tape itself, trying to make out what they are all made of. The caption reveals that the cardboard box is empty and the wrapping paper ''is'' the present; as a materials scientist, Cueball is more enamored by the (strange and exotic) wrapping paper, far more than he would be by any actual present inside.

The punchline also compares Cueball to a cat. A common stereotype ([https://www.reddit.com/r/funny/comments/8zw63a/thanks_for_box_human_oh_and_the_cat_tree_it_came/ with lots of image proof, to boot]) about domestic housecats is how they enjoy playing with empty boxes and discarded wrapping paper much more than the cat toys contained therein.

{{w|Aramid}} fibers are a class of strong synthetic fibers, built from aromatic rings connected via amide linkages. {{w|Kevlar}}, a material commonly and perhaps most famously used as a [https://youtu.be/gPKbOrxgx-w bullet-resistant fabric for] {{w|Bulletproof vest#Soft armor|soft bulletproof vests}}, is an example of an aramid. Due to their strength, they can be quite durable, even when thin, as depicted in the comic.

{{w|Triboluminescence}} refers to a phenomenon where mechanically working on a material (in this case pulling on the tape) causes it to glow. Triboluminescence is still not well understood by materials scientists, so they may find such materials particularly appealing. One famous example comes from crushing Wint-O-Green Lifesavers mints, which creates [https://youtu.be/tW8q_JfmcbU particularly bright blue sparks] compared to other hard candies. Staying in the realm of wrapping, Scotch tape exhibits this property too, [https://www.technologyreview.com/2008/10/23/217918/x-rays-made-with-scotch-tape/ to a point where it can even be used as an x-ray]. Phosphors, not to be confused with the element {{w|Phosphorus}}, are substances that glow when exposed to some other, typically more energetic, form of radiation, and can be used to produce a desired glowing effect by taking less useful parts of the spectrum (e.g. beyond the visible, or in an unnecessary area of the visible one) and shifting that into more practical hues.

{{w|Structural coloration}} is a phenomenon where the coloration of an animal or plant is not produced via pigments but via structural interactions with visible light at the scale of a wavelength (e.g. diffraction gratings, thin-film interference). More generally, it can also be used to refer to artificial materials that have a similar effect.

The title text states that if a materials scientist gives you a gift, you should ask if regifting it requires any form of federal paperwork. This is because the materials scientist may have access to items which are dangerous and strictly regulated, such as {{w|polonium}} (an extremely radioactive element), {{w|fluoroantimonic acid}} (the strongest acid discovered), {{w|nitrogen triiodide}} (one of the most sensitive explosives in the world), and {{w|n-butyllithium}} (an extremely flammable, pyrophoric, and caustic compound).

==Transcript==
:[Ponytail and White Hat are standing on the left side of a small table looking at Cueball. He stands on the other side of the table holding a gift wrapped in paper with thick black stripes. He is trying to open the gift. On the table lies two gift on top of each other. The bottom is thin and the wrapping paper has thin black stripes on it. The top present is a white box with a thick black ribbon around it and a large bow on top.]
:Cueball: Where is this wrapping paper from? It's so thin, but I can't tear it. Is this aramid fabric?!
:Cueball: Maybe I can unpeel the... oooh, the tape flashes as I pull it up! Triboluminescence! Did you add a phosphor? It's so bright!
:Cueball: Wait, are these patterns structural coloration?

:[Caption below the panel:]
:Materials scientists are like cats- the best present you can get them is an empty box with cool wrapping paper.

==Trivia==
* The [https://www.explainxkcd.com/wiki/images/archive/4/49/20231122150210%21materials_scientists_2x.png original version] of the comic mispelled aramid as "amarid".

{{comic discussion}}

[[Category:Comics featuring Ponytail]]
[[Category:Comics featuring White Hat]]
[[Category:Comics featuring Cueball]]
[[Category:Science]]

2818: Circuit Symbols

2023-08-22T02:23:27Z

108.162.241.170: Added inductor to sheep

{{comic
| number = 2818
| date = August 21, 2023
| title = Circuit Symbols
| image = circuit_symbols_2x.png
| imagesize = 438x362px
| noexpand = true
| titletext = A circle with an A in it means that the circuit has committed a sin and has been marked as punishment.
}}

==Explanation==
{{incomplete|Created by a REALLY COOL SHEEP DIODE - Please change this comment when editing this page. Do NOT delete this tag too soon.}}
{| class="wikitable"
! Symbol !! Comic Description !! Comments
|-
| Switch
| Drawbridge
| The symbol represents a physical on/off switch in a circuit, but also resembles a medieval drawbridge.
|-
| Capacitor
| Overpass
| A capacitor is a component that can be used to hold electric charge, but also looks a bit like the map symbol for a highway overpass.
|-
| Ground
| Pogo Stick
| This symbol represents a connection to "ground" (aka earth for folks in the UK). If you squint, it also looks like a pogo stick
|-
| ?
| Sheep
| An inductor is a component that can be used to hold electric current, but is also very curly
|-
| Transformer
| Two sheep in love, trapped on opposite side of a fence.
| The input and output looks on a transform are represented as curly loops, which Randal claims resemble sheep, and the straight line (which represents the core) is a fence.
|-
| Battery
| Battery
| No joke, that's the symbol for a battery
|-
| None
| Baertty
| Randall seems to be mapping the vowels and 't's to the inner lines in the symbol, and asserting that if you sort them long long, short short, you need to put the vowels in the front and the 't's in the back.
|-
| Really None
| Batttttttttttery
| Or, you know, you could just throw in a ton of 't's.
|-
| Photodiode
| Check out this really cool diode
| A photodiode generates current in response to light (the arrows pointing at it.) Randall is instead pretending that the arrows are pointing at it because it's really cool.
|-
| Oscillator
| Wave Pool
| An oscillator generates signals at a given frequencies. A wave pool, it could be argued, is in fact a type of oscillator, just with water instead of electricity
|-
| Transistor
| Trolly Problem
| A transistor will switch on a current flow depending on the input from a input signal. Thus, it switches electricity in the same way that the trolly problem
switches the trolly. The symbol also somewhat resembles the usual pictorial depiction of the problem.
|}

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
picture of drawbridge:drawbridge

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