explain xkcd - User contributions [en]

2989: Physics Lab Thermostat

2024-09-26T17:34:03Z

172.71.146.211: /* Explanation */ make more explanatory

{{comic
| number = 2989
| date = September 23, 2024
| title = Physics Lab Thermostat
| image = physics_lab_thermostat_2x.png
| imagesize = 264x296px
| noexpand = true
| titletext = Hopefully the HVAC people set it to only affect the AIR in the room.
}}

==Explanation==
{{incomplete|Created by ChatGPT, an actual bot, with the help of human copyeditors and critics as found on the talk page. Do NOT delete this tag too soon.}}

This comic is about a thermostat in a physics lab which, instead of controlling the air temperature, adjusts the {{w|Boltzmann constant}} in the immediate area, a value relating temperature to energy equal to 1.38×10−23 J/K, where J is {{w|joule}}s, a unit of energy, and K is {{w|kelvin}}, a unit of temperature. The dial shows different values for the constant, implying that it can be changed, which is absurd because the Boltzmann constant has always been the same throughout the universe. In reality, there is no way to change the Boltzmann constant, so the comic is making fun of the idea of a scientist casually adjusting a fixed law of physics as if it were something simple like room temperature.

If the Boltzmann constant could be changed, it would directly affect how we experience temperature. The energy range on the dial relative to the actual Boltzmann constant corresponds to temperatures of 15°C (59°F) on the left, to 29°C (84°F) on the right, because raising the value of the constant would decrease the apparent temperature at the same energy level. The dial appears to be set to approximately 23°C (73°F), a not untypical desired room temperature within a fairly standard range of thermostat-style choice.  There have previously been control panels for properties of the universe in [[1620: Christmas Settings]] and [[1763: Catcalling]]. A thermometer including units compatible with this thermostat (after dividing by 2/3) is shown in [[2292: Thermometer]].

The title text builds on the absurdity of being able to adjust the Boltzmann constant. It suggests that if the constant could be changed, hopefully it would only affect the air in the room and not other substances. Imagining that this strange version of an HVAC ({{w|heating, ventilation, and air conditioning}}) system could contain such a change to ''just'' the room's air shows the ridiculousness of trying to isolate the effects of altering a universal constant.

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

:[A black circular dial is shown with a white indicator line at the upper right. The label above the dial, enclosed in a rectangular box, says:]
:Local Boltzmann Constant
:[The two extremes of the dial are labeled as follows, the first value on the left and the second value on the right:]
:1.418×10-23 J/K
:1.351×10-23 J/K
:[The indicator line is pointing to a position on the dial somewhere around 1.375×10-23 J/K (between the 12th and 13th large ticks clockwise out of 19 total).]
:[Caption below the panel:]
:Physics Lab Thermostat

{{comic discussion}}

[[Category:Physics]]

Talk:2971: Celestial Event

2024-08-15T06:24:50Z

172.71.146.211: reply

Unfortunately, this calculation doesn't account for the eventual end of total solar eclipses due to the tidal recession of the moon. [[Special:Contributions/172.69.246.142|172.69.246.142]] 05:31, 13 August 2024 (UTC)

:This is a great comment! Very much like something Randall would have written for title text. [[Special:Contributions/172.71.146.49|172.71.146.49]] 05:58, 13 August 2024 (UTC)
:: Agreed! Also, it seems like the article should have a footnote or separate section going full Randall, "Based only on the data given in this cartoon, what is the possible range of Randall Munroe's home location?" --[[User:AnnapolisKen|AnnapolisKen]] ([[User talk:AnnapolisKen|talk]]) 18:21, 13 August 2024 (UTC)
::: Speculating about people's addresses online is generally frowned upon, in court if nowhere else. [[Special:Contributions/172.68.14.183|172.68.14.183]] 00:50, 14 August 2024 (UTC)

Are all of these events really statistically independent or are e.g. active northern lights and cicada mergence more or less likely to happen at the same time of the year? {{unsigned ip|172.68.194.201|06:15, 13 August 2024}}

: Ooh, great question. It turns out cicadas only emerge in warm weather, particularly in summer, and <s>you can only see the northern lights in winter</s>. That's bad news for us, our superevent might never happen. [[Special:Contributions/172.69.90.3|172.69.90.3]] 01:03, 14 August 2024 (UTC) — edit: oops, I got it wrong. It turns out you can see them all year round. They're actually happening right now in some parts of the US.

This comic was published the same night that saw both the Perseids meteor shower and an unusually strong northern lights. Strangely, the omission of meteor showers in Randall's account of Celestial Events suggests that this is a coincidence. [[User:Mumiemonstret|Mumiemonstret]] ([[User talk:Mumiemonstret|talk]]) 11:43, 13 August 2024 (UTC)

One eclipse every 350 years is not "1/350" - that would imply the eclipse lasted the whole year. The numerator unit should be a minute or so, vastly changing the result. {{unsigned ip|172.70.39.114|13:16, 13 August 2024}}
: Actually, thanks to unit cancelation, Randall's math checks out. I really really feel that it shouldn't, but it does. It's 1/350 years because what you're calculating is "once every X years". It doesn't actually matter how long an eclipse lasts, so long as it's a sufficiently small amount of time so as to be treated as a single point in time. "When that point in time happens, how frequently will those other things be happening?". You can give that answer in days, years, or whatever other unit of time you prefer. Since we're giving it in years, the number we need is "how often (am eclipse occurs) each year" - [[Special:Contributions/172.68.14.185|172.68.14.185]] 23:32, 13 August 2024 (UTC)
:: Yes, I came back to correct myself on this after more reflection. The implied unit is Event and this is the only such non-dimentionless factor. {{unsigned ip|108.162.245.186|23:40, 13 August 2024}}
: Tru dat, as are the comments regarding changes over time in eclipse parameters and the effects of time approximations. However, if we let "4 minutes" be the mean time of totality for an eclipse, and insert that term (for the record, 7.6E-06) for "1" in "1/350", the equation's solution becomes 4E+14, orders of magnitude greater than the age of the universe and, IIRC, well into its projected "heat death". The joke appears to reside in the proximity of Randall's solution to the commonly-accepted age of the Earth, making the solution "just possible". More "accurate" solutions would not be funny, and we would not have seen this comic.[[Special:Contributions/162.158.41.227|162.158.41.227]] 17:11, 13 August 2024 (UTC)
::In the "1/350years", I took it to mean that the unitless "1" represented a day (within which an eclipse occurs, and across this period would also extend the various other conditions). By treating all other unit-laden values as correctly converted to the number in the term of days (and back-converted to the 'more convenient' billions of years for the result), it probably ...not that I did the mathematics to check this... comes out as Randall suggests.
::If, indeed, the length of an (average, as of Earth's current configuration) eclipse, and all other values were understood as proxies for the "number of eclipse-lengths" (except for the uncloudy sky fraction, which is always a unitless half through cancelling out) then you might end up with a result that's different. But the way to check this is to accept the answer (in billions of years) and all the others with time-lengths (respectively) and work out the rough united-length of the "1" by to identify what unit would best fit that. But I leave that to whoever ''really'' wants to dive that deep into it, as the next logical step beyond mere attempted pedantry. [[Special:Contributions/172.68.205.164|172.68.205.164]] 20:22, 13 August 2024 (UTC)
: Every other 2 billion years, on days when it's cloudy or raining, the neighborhood ''doesn't'' get to see the spectacular show. [[Special:Contributions/162.158.154.98|162.158.154.98]] 19:19, 13 August 2024 (UTC)
::So just like the olympic games: They happen every 4 years, while also every 4 years, but offset by 2, there are the olympic winter games... --[[User:Lupo|Lupo]] ([[User talk:Lupo|talk]]) 05:43, 15 August 2024 (UTC)

There are competing factors with regard to the eclipse. Obviously total eclipses don't last for an entire year {{cn}}, but in the distant past when the Moon was significantly closer, they occurred much more frequently than once every 350 years. Far enough back, the moon was significantly larger in the sky and orbited much more rapidly making total solar eclipses a much more common event (even if nobody with eyes was around to see). Using constants for probabilities when things have significant variation is tricky. [[User:Galeindfal|Galeindfal]] ([[User talk:Galeindfal|talk]]) 14:26, 13 August 2024 (UTC)
:I just added (without having seen the above comment) something that deals with that. Actually, that and the way that the 'beat frequency' may ''just'' fail to create an all-effect maximum due to it not being a strictly repeating frequency (if you have an eclipse on one date, with a "1 event in 350 years" calculation for your location/latitude, it doesn't preclude more than one per 350 years or two separated by vastly more than 350 years - though still likely to get "N+1" eclipses over any given 350xN year period for higher Ns).
:If it's a combinatorial experience of fully periodic frquencies (such as with [[1331: Frequency]] then you can be precise over the beat-frequency, but any statistical perturbation can make a 'full hit' into a 'not-fully hit' event quite easily. At its simplest, though the chances of any given day (or useful fraction of a day) of being clear-skied may be 50%, it's not as simple to say "yesterday was cloudy, tomorrow will be clear", or vice-versa. Perhaps slightly more useful to say that than "the year just gone had no clouds, so this year will be full of them" or imagining that every second you could glance up and see "clouds...", "no clouds...", "clouds...", "no clouds...". The meteorological 'calculations' would never be anywhere near as simple as even the (future-trends modified) far-future predictability of the astronomical effects. The biologist might be able to be reasonably sure that the season-locked emergence of a given cicada brood will actually continue to satisfy ''their'' contribution to the calculation for much longer than the weatherman might (though they'd have to admit to the high probability that an ecological upset would flat out end any chances before any of the other forecasts become too hazy to rely upon).
:So the changing of frequencies over the time of the 9calculated) meta-beat's recurrance will make for an compoundedly-chaotic 'actual' meta-beat (assuming it ever completes). This includes the possibility that it actually re-meshes its individual occurances into an actually far more frequent coincidence (two consecutive cicada emergences could end up ''both'' being accompanied by all the other requirements). Depends how much you take at face-value, rather than as a rough and ready 'approximation' for fun-and-non-profit... [[Special:Contributions/172.68.205.164|172.68.205.164]] 20:22, 13 August 2024 (UTC)

The adjustment due to leap years is far dwarfed by the approximate nature of "20 days" and "2 months" in some of the events. [[User:Barmar|Barmar]] ([[User talk:Barmar|talk]]) 15:06, 13 August 2024 (UTC)

Don't know how it could be calculated in, but there's a fundamental conflict between the solar eclipse and aurora borealis. Solar eclipses are only visible during the day {{cn}}, but the aurorae aren't symmetrical around the poles and drag further equator-ward on the night side of the planet. So the occurrences of Northern lights that would reach to Boston latitudes on the *day side* of the planet so as to be visible during a solar eclipse would be much, much rarer (closer to Carrington-event rarity, currently pitched at once every 100 to 1000 years instead of the 11 Randall used, but even then it'd have to be a particularly strong event). [[Special:Contributions/172.70.230.142|172.70.230.142]] 13:34, 14 August 2024 (UTC)

;Big Bang theory
If he had included all these events happening on a Tuesday or a Thursday then we're getting close to 1 every 14 billion years. A time which everyone's neighbourhoods had a really big show. [[User:Kev|Kev]] ([[User talk:Kev|talk]]) 02:36, 15 August 2024 (UTC)

;Terrible explanation
Someone has to say it. The explanation is so long and convoluted that it serves substantially more to confuse than to explain. Someone please edit it mercilessly. [[Special:Contributions/172.69.33.62|172.69.33.62]] 05:14, 15 August 2024 (UTC)
:I bit the bullet. I'm sure I left some important stuff out, but more sure I deleted more unimportant stuff. [[Special:Contributions/172.71.146.211|172.71.146.211]] 06:24, 15 August 2024 (UTC)

2963: House Inputs and Outputs

2024-07-25T17:38:32Z

172.71.146.211: /* Explanation */ table title

{{comic
| number = 2963
| date = July 24, 2024
| title = House Inputs and Outputs
| image = house_inputs_and_outputs_2x.png
| imagesize = 740x684px
| noexpand = true
| titletext = People think power over ethernet is so great, and yet when I try to do water over ethernet everyone yells at me.
}}

==Explanation==
{{incomplete|Created by a possible reference to [[1037: Umwelt]] in panel 16 - Please change this comment when editing this page. Do NOT delete this tag too soon.}}

This is another comic in a series depicting {{w|confusion matrix|confusion matrices}}, similar to [[2420: Appliances]], [[2813: What To Do]] and [[1890: What to Bring]]. It is arranged as a table of five columns of conduits to and from a house, by five rows of resources and people, each of which typically enter, exit or both enter ''and'' exit the house via a least one of the identified conduits. The table cells have a green background for compatible methods of transit and a red tint is used for the more problematic pairings. Each panel can be read as "[row label] [entering and/or exiting] the house via the [column label]", for example, "Fresh water entering the house via the well".

{| class="wikitable" style="background-color: lightpink;"
|+ House Inputs and Outputs
! !! Well !! Garage !! Power lines !! Front door !! Septic tank
|-
! Fresh water (Input)
|style="background-color: palegreen;"| The purpose of a well is usually to pump fresh water into the home, primarily for drinking or washing. It may be unnecessary in many places if a reliable {{w|water supply network}} is available. || Long gone are the days of {{w|Labours_of_Hercules#Fifth:_Augean_stables|having to clean up after your primary mode of transportation}}, for most people. || Water either shouldn't, or cannot be carried through electrical lines. || Many people prefer to control the amount of water they get, and the water may damage things inside the house. || Most people don't want anything they drink to contain (or go through pipes that have contained) sewage.
|-
! Cars (Input/Output)
| Most cars manufactured in recent years can't fit inside a well.
|style="background-color: palegreen;"| Garages are in fact built for the storage of cars and other similarly-sized vehicles. Placing a car in one will both help protect it from the elements and make it easier to access from inside your own home. || As of yet, cars cannot be transferred through power lines and require roads to travel on. However, this could significantly reduce travel costs. || Most cars can’t fit through doors, apart from the garage door. || Comedian {{w|Garrison Keillor}}'s 2008 ''More News from Lake Wobegon'' includes a story where an old septic tank is discovered to actually be a buried car.[https://theseriouscomedysite.com/comedy-cd-or-download/garrison-keillor-more-news-from-lake-wobegon/]
|-
! Electricity (Input)
| This would contaminate your water supply. || In the United States, lightning is responsible for causing around 24,600 structure fires annually, resulting in $8 to $10 billion in losses.
|style="background-color: palegreen;"| Power lines are designed to facilitate the connection of individual homes to the broader local power network. [[Randall]] omits the fact that electricity can also be an output; e.g. houses with solar panels regularly export electricity too. || {{w|Benjamin Franklin}} supposedly independently{{acn}} re-invented {{w|Prokop Diviš}}'s {{w|lightning rod}} to prevent lightning strike damage to structures. || As Knit Cap demonstrates, this would not be the most convenient idea.
|-
! People (Input/Output)
|style="background-color: lightpink"| This depicts a view from inside a well, a very dangerous place for most people.{{Citation needed}} As a [[:Category:Comics with inverted brightness|dark scene]], it is drawn red-on-black. The motif resembles poster art for the 2002 horror movie remake ''{{w|The Ring (2002 film)|The Ring}}'', which involves a girl left to die in a well becoming a vengeful ghost (see also [[396: The Ring]]).
|style="background-color: palegreen;"| A person can enter and exit their home through a garage door, provided the garage has an internal door to the rest of the home. Not the best way to welcome guests though. || Overhead power lines to homes are generally not strong enough to climb, and attempting to do so incurs a very serious risk of electrocution.
|style="background-color: palegreen;"| The front door of a home is designed for entry and exit of humans and similarly sized items. || In general, people find crawling through waste unwanted. Also, the septic tank is not connected to the street.
|-
! Sewage (Output)
| Sewage in drinking water can cause disease. It is/was the main cause for most {{w|cholera}} epedemics.
|colspan=3| Sewage spills are smelly, disgusting, hard to clean, and can destroy carpets, floors, and drywall.
|style="background-color: palegreen;"| A {{w|septic tank}} is an underground chamber through which wastewater flows for basic {{w|sewage treatment}}.
|}

The title text references {{w|Power over Ethernet|power over ethernet (PoE)}}, first implemented in the early 2000s, which passes electric power along with data on twisted-pair Ethernet cabling. This is a welcome development, as it removes the need for many lower-power network-connected devices to have independent power supplies, usually simplifying their installation and relocation. While networked water delivery ("running water") is also a welcome development, doing so over ethernet cables would be disastrous, risking the destruction of linked electronic devices (nearly all of which are water-intolerant) while not providing enough water for 'normal' use. Randall would get off easy if he were merely to be yelled at.

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

:[A 5x5 grid of squares. The columns are labeled: Well, Garage, Power lines, Front door, Septic tank. Each row's label has an arrow and a house next to it. The rows are: Fresh water (horizontal arrow towards house), Cars (two-directional horizontal arrow and house), Electricity (horizontal arrow into house), People (two-directional horizontal arrow and house), Sewage (vertical arrow out of bottom of house).]

:Well, Fresh water: [green]
::Voice from house: Mmm! Refreshing!

:Garage, Fresh water: [red]
::''Fwoosh''

:Power lines, Fresh water: [red]

:Front door, Fresh water: [red]
::Voice from house: Stop it!
::''Fwoosh!''

:Septic tank, Fresh water: [red]
::Voice from house: Eww.

:Well, Cars: [red]

:Garage, Cars: [green]

:Power lines, Cars: [red]

:Front door, Cars: [red]
::Voice from car: Do you think I scratched the paint?

:Septic tank, Cars: [red]

:Well, Electricity: [red]
::Cueball's laptop: ⚠Low battery

:Garage, Electricity: [red]
::''BOOM''

:Power lines, Electricity: [green]

:Front door, Electricity: [red]
::''BOOM''

:Septic tank, Electricity: [red]
::Knit Cap: Why won't my console turn on?

:Well, People: [red (and black)]

:Garage, People: [green]
::Cueball: Bye!

:Power lines, People: [red]
::Cueball: Bye!

:Front door, People: [green]
::Cueball: Bye!

:Septic tank, People: [red]
::Cueball: Bye!

:Well, Sewage: [red]
::Voice from house: ''Why do I keep getting sick???

:Garage, Sewage: [red]
::Cueball: Oh no.

:Power lines, Sewage: [red]
::Cueball: Eww.

:Front door, Sewage: [red]
::Cueball: Oh ''no''.

:Septic tank, Sewage: [green]
::''Flush''

{{comic discussion}}

[[Category:Comics with color]]
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Megan]]
[[Category:Comics featuring Knit Cap]]
[[Category:Confusion matrices]]
[[Category:Multiple Cueballs]]
[[Category:Charts]]

Talk:2910: The Wreck of the Edmund Fitzgerald

2024-03-23T06:21:11Z

172.71.146.211:

well ''that'' was early. [[user talk:lettherebedarklight|youtu.be/miLcaqq2Zpk]] 11:47, 22 March 2024 (UTC)

This singer is a bit fast and loose with the rhyme-scheme; aAbCd(?D)eC with the "dD", especially, being Go+Most, Tune+Words(!), ¿This/As?+Words and Crimes+Time. And scansion is potentially off (mid-line endings definitely are). I would hope that another shipwreck wouldn't happen until this new guy has tightened up his own art a little. (But once he gets good enough, fair enough!) [[Special:Contributions/172.71.242.161|172.71.242.161]] 12:57, 22 March 2024 (UTC)

:"For it's challenging trying to write good" [[User:N0lqu|-boB]] ([[User talk:N0lqu|talk]]) 14:00, 22 March 2024 (UTC)

:"This singer is a bit fast and loose..." This is Gordon and his First Draft. Just strumming to see if the song has legs (fins?). We know Gordon could fiddle the rhyme and line-breaks as good as anybody. But prolly not on a dock on Lake Superior in November. (OTOH Sittin' on The Dock of the Bay, Otis Redding wrote in August on a rented houseboat in Sausalito, California; a much nicer workplace.) --[[User:PRR|PRR]] ([[User talk:PRR|talk]]) 23:05, 22 March 2024 (UTC)

Is the Cameron accusation also suggesting that he has actual time travel technology, as shown in his Terminator movies? [[User:Barmar|Barmar]] ([[User talk:Barmar|talk]]) 14:19, 22 March 2024 (UTC)

How long should we wait before using peoples' deaths as entertainment? Relatives and friends of the crew are still alive. Are the terrorist attacks of 2001 open yet for parody? ...or wait another decade or two? Please consider others. [[Special:Contributions/172.69.214.108|172.69.214.108]] 14:26, 22 March 2024 (UTC)
: Given that the original song turned it into entertainment less than a year after, and it's been widely parodied pretty much ever since, I think you may, if you'll pardon the phrase, have missed the boat on that one.[[Special:Contributions/141.101.98.53|141.101.98.53]] 14:59, 22 March 2024 (UTC)
::Although it was performed as entertainment, the song was written as a kind of memorial or tribute. That's quite different from using the accident as fodder for a joke. [[User:Barmar|Barmar]] ([[User talk:Barmar|talk]]) 18:38, 22 March 2024 (UTC)

: It's important to consider sides. Like, deaths of Russian soldiers in Ukraine are open to parody immediately because they are enemies. -- [[User:Hkmaly|Hkmaly]] ([[User talk:Hkmaly|talk]]) 18:39, 22 March 2024 (UTC)

What if Cueball bribed Gordon Lightfoot to bribe the mechanic so he could write a song about Lightfoot bribing the mechanic to write a song? [[User:AoPS is superior|AoPS is superior]] ([[User talk:AoPS is superior|talk]]) 00:24, 23 March 2024 (UTC)

Was it rammed by the Cat Stevens? [[Special:Contributions/172.70.211.144|172.70.211.144]] 04:57, 23 March 2024 (UTC)

The flags on the upside down eighth notes are backwards [[Special:Contributions/172.71.146.211|172.71.146.211]] 06:21, 23 March 2024 (UTC)