explain xkcd - User contributions [en]

2952: Routine Maintenance

2024-07-02T04:03:01Z

172.68.2.100: /* Explanation */

{{comic
| number = 2952
| date = June 28, 2024
| title = Routine Maintenance
| image = routine_maintenance_2x.png
| imagesize = 299x413px
| noexpand = true
| titletext = The worst was the time they accidentally held the can upside down and froze all the Earth's magma chambers solid.
}}

==Explanation==
{{incomplete|Created by an ONCOMING LETHAL DUST CLOUD - Please change this comment when editing this page. Do NOT delete this tag too soon.}}

A recommended routine maintenance step for many electronics, such as desktop computer towers, is to remove the buildup of dust on a regular basis. This bit of routine maintenance can help prevent the electrical components from overheating, and lengthen the lifetime of these electronics. To make this job easier, safer, and cleaner, there exist {{w|Gas duster|cans}} of high-pressure gas, as depicted, which force through high-flow gas to displace the dust. (Attempting to do this with air from the lungs would be less effective, may add unintended moisture to the electronics, and could result in a faceful of dust).

The comic suggests that a similar maintenance step is performed on the Earth itself, blowing gas into the Earth to force out the dust from its magma chambers. However, filling the atmosphere with dust would be unhealthy and fatal to living beings, so as a safety measure everyone would have to take shelter.

This may be a reference to one theory about the K-T extinction event — that a crashing meteor sent so much dust into the air that it killed off many plants and animals, including all non-avian dinosaurs, in a much wider area than that directly affected by the initial impact. Those lineages that chanced to survive the global effects must have been able to escape the worst of the disrupted ecosphere while the worst of the atmospheric effects subsided, and were then able to exploit various newly vacant (and/or changed) environmental niches. (This would include our own mammalian ancestors, and the avian dinosaurs that led to todays birds; some of them may, perhaps, have survived by already being more inclined/suited to living in burrows.) However, this dust cloud would have lasted longer than the 48 hours suggested in the comic.

The image suggests that the "routine maintenance" for Earth would involve using the {{w|Hawaii hotspot}} (possibly <em>via</em> its most active volcano, {{w|Kilauea}}), as the point to insert the high-pressure gas, causing volcanoes to erupt in Iceland, the {{w|Aleutian Islands}} or the {{w|Kamchatka Peninsula}}, the {{w|Andes}}, and elsewhere; the two geographically-indeterminate plumes may represent Italy and Indonesia.

The title text mentions using the can upside-down, and this freezing solid the magma chambers. Pressurised canisters of "air", as with similar aerosol sprayers, contain a propellant gas that condenses into a liquid when compressed. When the spray valve is opened, the release of pressure allows some of the liquid to evaporate and take the place of the released gases, or become some of the gas subsequently released (or all of it, if its purpose is not to spray other contents). The transition of the propellant liquid/gas from dense liquid to space-filling gas requires it to 'boil off', this process needing to pick up {{w|Enthalpy of vaporization|heat (or 'enthalpy') energy}}. Under typical operation, the cooling liquid/gas takes heat from the general mass of the can itself as it tries to attain thermal equilibrium. As a result, the can (and the expelled gases) will be cooled a little. Then (ultimately) heat will also be taken from anything touching or surrounding the slightly cooled can and its spray. This is precisely how a purposeful refrigerant acts, either as a one-time process or as a reversible cycle where repressurising a suitable gas can 'release' heat (the heat/enthalpy of condensation) at the 'hot side' of a refrigerator, returning the gas in the system to liquid that it can later let boil again and cool the 'cold side' of the refrigerator.

It is not normally useful for such a can to allow the liquid propellant-in-waiting to exit the container, as it would waste its usefulness as a source of pressure once it does. But by holding the container the wrong way up (which way that is being dependent upon its design, and intended use...) the pressurised contents push the liquid out via the nozzle's stream. The now exposed propellant is now free to evaporate into the air at atmospheric pressure, typically much lower than the constraints it had within the can, after landing directly upon whatever the can was sprayed at. The resulting demand for heat energy (much more rapid than normal, and likely concentrated upon a much smaller target than the can itself represents) produces a greater localised drop in temperature and can lead to freezing nearby liquids (which may or may not be intended/useful). Of course, the total 'cooling effect' of such a can does not change, depending upon how it is (mis)used, it merely changes the extent (and lifetime) of application, and how extreme the temperature change may be within a much more limited 'liberation' of its cooling ability.

Spraying "canned air" with the can inverted is a party trick used to very quickly cool beverages, being able to bring them down from room temperature to ice cold in seconds if performed correctly.

{{w|Freeze spray|Some spray cans are designed to freeze objects}}, e.g. to help in plumbing repairs or finding overheating electronic components. Freeze spray is also used in medical applications. These require careful use to avoid unintentionally damaging exposed skin or objects that can be damaged by local temperature differences, such as glass.

Given the location of the planetary-scale dust-busting 'air canister', it may be considered confusing which 'way up' is the correct orientation, given that Earth-gravity would be pulling the contents sideways (however that changes what the nozzle ends up ejecting from the can itself). But such a large can would also have its own significant internal 'can-centric' gravity that possibly (depending upon how full of still-liquid propellant it is) exceeds that of the Moon, possibly letting all the denser liquid hold itself into the centre of the canister, even against the nearby Earth's gravity. Being significantly closer to the Earth than the Moon is, this can could also be a far greater influence upon Earth's own tides (not alluded to in the comic), making the dusting of the atmosphere or the freezing of some of its magma secondary issues to the sheltering population. But if magma froze to the extent of disrupting or disabling the {{w|Earth's magnetic field}}, this "secondary" issue could quickly become primary, even existential.

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

:[The nozzle of a "Dust-Off" (compressed air) gas duster can is pointing into a hole on the Earth's surface in the Pacific Ocean around where Hawaii is located, and its trigger is pressed as an arrow indicates, resulting in dust clouds being released from five visible spots of the Earth. These eruptions can be seen in the Aleutian Islands or Kamchatka Peninsula, Iceland, the Andes, and two further in the eastern hemisphere on the other side of the Earth.]

:[Caption below the panel:]
:I know routine maintenance is important, but I hate how we all have to take shelter for 48 hours every year while they flush out the Earth's magma system for cleaning.

{{comic discussion}}

[[Category:Geology]]

2948: Electric vs Gas

2024-06-19T18:34:04Z

172.68.2.100: /* Explanation */ fix typo

{{comic
| number = 2948
| date = June 19, 2024
| title = Electric vs Gas
| image = electric_vs_gas_2x.png
| imagesize = 284x385px
| noexpand = true
| titletext = An idling gas engine may be annoyingly loud, but that's the price you pay for having WAY less torque available at a standstill.
}}

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

Internal combustion engines are the most common technology used to propel vehicles. In US vernacular, the most common motor fuel is known as "gasoline", or "gas" for short, leading to these engines being referred to as "gas engines".

Electric motors, which were long considered to be impractical for most forms of transportation, are rapidly rising in popularity, and now constitute 18% of all global vehicle sales. [[Randall]] has long been a strong proponent of electric vehicles.

In this strip, [[White Hat]] claims to be comparing the pros and cons of electric motors and gas engines. The joke is that every point he makes goes in favor of electric motors. Despite it being posed as a dilemma, it's very clear which side of the debate White Hat is promoting.

The strip offers the following points in favor of electric motors:

- "Cleaner and more efficient". Internal combustion engines produce and vent harmful combustion products, while electric motors produce no byproducts. The efficiency of both gas and electric motors vary, but the typical vehicle in the US converts around 25% of available energy into motion, while the typical electric vehicle is in the neighborhood of 80%. (It should be noted that all of this refers to the motors only, and ignores how the fuel and electricity are produced).

- "More powerful". While both types of engines can be built for very high power, electric motors can often carry more power in a compact design.

- "Annoyingly loud". Internal combustion engines, by their nature, produce significant noise. Despite noise attenuation measures (such as mufflers), they contribute significantly to urban noise. Properly designed electric motors are nearly silent.

- "WAY less torque available at standstill". Internal combustion engines need to continually operate within a specific range of rotational speeds, which means that a complex system of transmission gearing is needed to convert this motion into the specific speeds needed at the wheels. When starting from a stand-still, this means that torque must be applied to the wheels relatively gradually to avoid stalling the engine. Electric motors, by contrast, can apply nearly all available torque, even at a standstill. This results in electric vehicles having significantly better acceleration and engine responsiveness.

It should be noted that White Hat is deliberately confining his arguments to electric vs gas ''motors'' rather than electric or gas-powered ''vehicles''. Doing so ignores the basic reason why internal combustion vehicles have long dominated transportation: hydrocarbon fuels are a very dense and fairly easy to handle form of energy storage. Providing electrical power to a moving vehicle requires a large number of high-capacity batteries, which was impractical until comparatively recently (other methods, such a fuel cells, have been proposed but remain experimental).

A more comprehensive comparison would include the cons of electric vehicles, including:

- Higher cost (primarily due to the cost of batteries)
- Long charging times
- Limited range
- Limited charging infrastructure

Advancing technologies may change how serious these cons are, but they currently remain genuine issues.

White Hat's argument that electric motors are superior in every way is likely true, if we consider only the motor itself. This is evidenced by the fact that gas motors are virtually never used in applications where a reliable source of electricity is available to run an electric motor. However, if we consider the entire system of motor, power, and power storage, the matter becomes significantly more complex.

==Transcript==
:[White Hat, with his palm raised, is talking to Cueball.]
:White Hat: Electric motors and gas engines each have their pros and cons.
:White Hat: On one hand, electric motors are cleaner and more efficient. On the other hand, electric motors are more powerful.
:White Hat: So it's hard to say which is better overall.

{{comic discussion}}

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

Talk:2933: Elementary Physics Paths

2024-05-18T14:56:34Z

172.68.2.100:

First comment, heh. [[User:Psychoticpotato|Psychoticpotato]] ([[User talk:Psychoticpotato|talk]]) 20:27, 15 May 2024 (UTC)
:See also [[1258: First]]. --[[Special:Contributions/162.158.159.7|162.158.159.7]] 23:21, 15 May 2024 (UTC)
::Let me have my first "first" moment, man. [[User:Psychoticpotato|Psychoticpotato]] ([[User talk:Psychoticpotato|talk]]) 12:46, 16 May 2024 (UTC)
:::Could this be the last first? Or just the first of the last firsts. [[User:N0lqu|-boB]] ([[User talk:N0lqu|talk]]) 14:16, 17 May 2024 (UTC)

I assume the cosmology comment from the alt text is related to the speculative nature of dark matter and dark energy, but I am too ignorant of of cosmology to know if there is something more specific being referenced.[[Special:Contributions/172.69.23.203|172.69.23.203]] 22:27, 15 May 2024 (UTC)
:I think its more jokinly questioning the knowlege of the cosmos, saying "space is big, so are we 100% that EVERYTHING is made of these complicated little things, or just the parts we can see?" [[User:Apollo11|Apollo11]] ([[User talk:Apollo11|talk]]) 00:26, 16 May 2024 (UTC)

::I thought it was a reference to the incompatibility of the leading cosmological theory (Relativity) with Quantum theory. [[Special:Contributions/172.68.210.117|172.68.210.117]] 02:49, 16 May 2024 (UTC)

Am I the only one where it seems like the explanation was written by an AI? It seems like obvious things are left out, like the presence of dark matter in astronomy, or saying “quantum physics” instead of “quantum field theory”. It’s like in some areas it could be convincingly explaining without knowing, a little like chatgpt does. However, I’m thinking a lot of the explanations are like that and I’ve probably participated in it myself … [[Special:Contributions/172.68.23.215|172.68.23.215]] 00:46, 16 May 2024 (UTC)
:The reason we're using "Quantum Theory" (at least my reason) is because thats what the comic used [[User:Apollo11|Apollo11]] ([[User talk:Apollo11|talk]]) 00:59, 16 May 2024 (UTC)

According to the Copenhagen Interpretation, it's not determined whether a physicist studies Condensed Matter or Quantum Field Theory until we open his box. [[User:Doctorhook|Doctorhook]] ([[User talk:Doctorhook|talk]]) 02:45, 16 May 2024 (UTC)
: According to the Communist Russia Interpretation, the Universe studies physicists.[[Special:Contributions/172.71.178.172|172.71.178.172]] 08:22, 16 May 2024 (UTC)

you guys really need to solve your chatgpt problem
--[[Special:Contributions/172.70.143.28|172.70.143.28]] 03:59, 16 May 2024 (UTC)

Schrodinger's 'cat box thought experiment' is more complex than even Schrodinger realised, since for the duration of the experiment the cat assumes EVERY possible quantum state, including 'not actually in the box' and 'suddenly not being a cat any more'.
[[Special:Contributions/172.70.91.231|172.70.91.231]] 05:09, 16 May 2024 (UTC)

Schrodinger did not argue against QM; he argued against a certain interpretation of it. Specifically, he argued that QM does not tell us how things really are; at most, it tells us what we can detect about those things. His cat in a box idea aims to make clear that we do not know what happens between observations and that using QM to describe this leads to nonsense.
[[Special:Contributions/172.70.46.13|172.70.46.13]] 06:44, 16 May 2024 (UTC)
:I removed the "further examples" and the mentioning of Schrödinger. Interesting for sure, but not relevant for the explanation of the comic. Schrödinger isn't even mentioned in the comic... [[User:Elektrizikekswerk|Elektrizikekswerk]] ([[User talk:Elektrizikekswerk|talk]]) 07:26, 16 May 2024 (UTC)

It feels like Randall has gone down the same Wikipedia rabbit hole that I have (spurred on by another comic). The universe is full of extremely weird things on every level. Even the Copenhagen Interpretation of QM isn't actually one interpretation. Everyone has different ideas because it's all so weird. I remember my physics teacher telling me about the time before QM was discovered when it seemed like we had figured out most of physics and now it seems like we barely know anything. [[User:Brycemw|Brycemw]] ([[User talk:Brycemw|talk]]) 13:31, 16 May 2024 (UTC)

It seems like there should be a third branch for chemistry, leading to biology. Just putting a bunch of atoms together gives a bunch of new, unrelated properties in the new molecules compared to their constituent atoms. When you look at organic chemistry, especially the self-perpetuating version (life), then the level of complexity is ''huge''. {unsigned|Nutster|16:04, 17 May 2024}}

I was reading it, and as 172.68.23.215 said, it looks like Kyrodes put in multiple overriding edits which directly erased the original explaination in lieu of a ChatGPT version (analysis courtesy of gptzero). I'd personally prefer there being more human-made stuff here, and some of the writing isn't exactly coherent... But this isn't up to me to decide, eh? [[User:Eelitee|Eelitee]] ([[User talk:Eelitee|talk]]) 21:25, 17 May 2024 (UTC)

Yesterday I was trying to read a journal article that was trying to model the way water moves through a soil column and has some of its impurities removed. They were using a system of 12 simultaneous partial differential equations, had dramatically run out of letters for naming variables, constants, and functions, and were nesting equations three deep to try to make the PDEs readable. And this was AFTER they made a large number of simplifying assumptions. To top it off, the results aren't even perfectly accurate for already highly purified water running through a column in a super controlled environment. Reality is complicated, y'all.[[Special:Contributions/172.68.2.100|172.68.2.100]] 14:56, 18 May 2024 (UTC)

Talk:514: Simultaneous

2024-03-28T17:05:38Z

172.68.2.100:

When reading "one of whom is moving at close to the speed of light compared to the other" in the explanation I'm reminded of the (non-)joke "What's the difference between a duck? One of its legs is not the same." Because of frames of reference ''both'' of them are moving at close to the speed of light compared with the respective other. Which doesn't affect the disagreement about the simultaneity of observed events, of course. That still potentially/inevitably happens. [[Special:Contributions/31.111.87.233|31.111.87.233]] 13:36, 28 May 2013 (UTC)
:Fixed. I also removed the acceleration bit, as it's not relevant here and made the sentence too wordy and confusing. --[[User:Someone Else 37|Someone Else 37]] ([[User talk:Someone Else 37|talk]]) 03:10, 31 March 2014 (UTC)

You don't have to move close to the speed of light to create this effect, you just need to go close to the speed of light to make a noticeable difference.

Any amount of movement would cause this difference in perception, it would just be so small you would not notice it. In fact very accurate clocks have demonstrated this simply by flying one in a jet around the world while the other sat still.

Even if you walked around the world there would still be some effect. So there is no need to assume the there was any near speed of light sex, just a disparity in the amount of movement made by the two partners. [[Special:Contributions/184.66.160.91|184.66.160.91]] 19:37, 7 July 2013 (UTC)

OH GOD WHAT IS THIS COMIC?!? [[Special:Contributions/172.68.2.100|172.68.2.100]] 17:05, 28 March 2024 (UTC)

2894: Research Account

2024-02-15T15:45:09Z

172.68.2.100:

{{comic
| number = 2894
| date = February 14, 2024
| title = Research Account
| image = research_account_2x.png
| imagesize = 291x479px
| noexpand = true
| titletext = Focus of your research: EXTREME PETTINESS AND UNWILLINGNESS TO LET ANYTHING GO
}}

==Explanation==
{{incomplete|Created by a BOT THAT WILL ARGUE WITHOUT MERCY - Please change this comment when editing this page. Do NOT delete this tag too soon.}}

In the comic, [[Cueball]] is filling out a form to register for a research account. Such accounts are typically intended for people doing serious work in the relevant field, who need access to the materials provided to support that work. Cueball, however, has filled out “other/none” for institution, and “to win an argument with someone in a group chat” for “reason for requesting access to our datasets”, making it clear that his interest is both petty and personal. While this may be honest, it doesn't match the assumed purpose, and he may be worried that it might mean that his registration would be rejected or subsequently cancelled. So he then selects all and deletes his previous justification, replacing it with “independent research”, which is an accurate, if generic, explanation.

In the title text, he says that his research focuses on “extreme pettiness and unwillingness to let anything go” (in all caps), further reinforcing the reason that he is doing this solely to win an argument. It is possible this is a pun on different meanings of the word "focus" - while the question about the focus of one's research is typically about the subject matter they are researching (raft building in fire ants, etc), Cueball appears to be writing about what drives his desire to do research. This is more like the idea of a "spell focus" in fantasy settings, an object meant to allow a spellcaster to focus their energies and perform magic. Similarly, Cueball is not doing research INTO pettiness, but rather is focusing entirely on his pettiness as his main reason to perform research and achieve his goals.

It is not uncommon for online forms to include fields like these, where it's unclear what, if anything, will be done with the input, and therefore how much it matters what is entered. It's unlikely that anyone would have the capacity to review all the freetext answers submitted, and in any case, by the time they did so, Cueball would presumably have already accessed the materials he wanted. They may be able to mine the data for insight about their users, or simply be collecting data against a vague ambition to do so in the future. However, even if nothing is subsequently done with the data, the very existence of the field may be serving a purpose, by deterring some people from completing the registration for frivolous purposes (though as Cueball illustrates, this is not infallible).

The feel of this comic is slightly similar to [[1346: Career]].

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

:[Cueball sits at a desk, typing at his laptop computer.]

:[Above him, there is a box indicating his computer screen.]

:[Caption above screen:] Application for research account

:[Under the caption, there is a panel, representing the computer screen; in the panel: (cut off from above) "Institution: Other/none", where the option has been selected from a drop-down menu. Under that is written "Reason for requesting access to our datasets:", under which is a comment field where "To win an argument with someone in a group chat" has been written. Under that, two long bubbles containing the words "Select all" and "Delete" separate another panel, with a panel featuring the comment field with "Independent research" written. The cursoar can still be seen blinking.]

:[Caption below the comic panel:]
:I never know how honest to be on these forms.

{{comic discussion}}

[[Category:Comics featuring Cueball]]
[[Category:Science]]