explain xkcd - User contributions [en]

Talk:3138: Dimensional Lumber Tape Measure

2025-09-08T23:49:52Z

80.189.2.17: .

I was under the impression this was actually a thing that exists, somewhere. (Separate and apart from so-called "shrink rules" used by patternmakers who create patterns for metal castings). No? [[User:JohnHawkinson|JohnHawkinson]] ([[User talk:JohnHawkinson|talk]]) 00:36, 6 September 2025 (UTC)

https://www.inchcalculator.com/actual-size-of-dimensional-lumber/ for reference --- MEL

: Wikipedia has {{w|Lumber#Dimensional_lumber|a similar table}}. Interestingly, if the values on this table are correct, the xkcd measure fails for the 8 x 8 board. [[Special:Contributions/2605:59C8:160:DB08:988B:772A:4E5:B209|2605:59C8:160:DB08:988B:772A:4E5:B209]] 02:18, 6 September 2025 (UTC)

:: >''the xkcd measure fails for the 8 x 8 board'' Studs and joists are routine repetitive structure and should be the same as their neighbors. 8x8 are non-routine; even in say a heavy mill building 8x8s are costly enough for the carpenter to measure or trim every column. --[[User:PRR|PRR]] ([[User talk:PRR|talk]]) 17:10, 8 September 2025 (UTC)
:: My house has near full-size 2x4s and 2x6. Very-dry trees were sawn on site, the saw set for 2.0" centers. Band saw has very narrow kerf. About 1.9". A profitable saw-mill would use a coarser blade and push the size down as much as customers would accept (and even a junior carpenter can tell an undersize stud by feel). But here they were clearing land as much as saving money. --[[User:PRR|PRR]] ([[User talk:PRR|talk]]) 17:10, 8 September 2025 (UTC)

:"I was under the impression this was actually a thing that exists, somewhere" - if doesn't exist now, it soon will. [[Special:Contributions/70.115.234.146|70.115.234.146]] 03:59, 6 September 2025 (UTC)

Thinking that there might be a typo in the comic - It says : A "1x8" IS "3/4 BY 7 1/8", yet it should be "3/4 BY 7 1/4".

I no longer want to be a lumberjack! [[Special:Contributions/2A02:2455:1960:4000:748F:2291:F005:1989|2A02:2455:1960:4000:748F:2291:F005:1989]] 06:57, 6 September 2025 (UTC)
:I'm a lumberjack and I'm OK. I sleep all night and I work all day! ;-) --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 05:31, 8 September 2025 (UTC)

This reminds me of when I changed my friend’s text replacements to be slightly misspelled whenever she tried to type a common word in college. She was getting a degree in linguistics and it was SO FUNNY 《プロキシ》(XKCD中毒者) 13:29, 6 September 2025 (UTC)
:She should have claimed that she was undertaking "applied linguistics" and investigating how to create a deliberate {{w|language change}}! [[Special:Contributions/92.17.62.87|92.17.62.87]] 20:23, 6 September 2025 (UTC)

I was told (and maybe this is wrong), that the dimensions are intended to represent the final thickness of a wall when drywall (usually 0.5" thick) is attached to the studs. [[User:Shamino|Shamino]] ([[User talk:Shamino|talk]]) 20:58, 6 September 2025 (UTC)
:I think that's just a convenient side effect. Of course, if the drywall is 1/2 thick, a wall with 2x4 studs will be 4.5 inch thick. [[User:RegularSizedGuy|RegularSizedGuy]] ([[User talk:RegularSizedGuy|talk]]) 22:22, 6 September 2025 (UTC)

:That would be pretty ahistorical, so I think it is indeed wrong. Drywall is a relatively modern invention, and I think the standardization of 2x4s as 1.5″ thick predates it (need to check that…but even if it didn't, then it would be worse). Wood lath and plaster walls are more like 5/8″ from the stud face, if not more. And, of course, in modern American multifamily residential construction 5/8″ walls are more common, or even double-5/8″ walls (making 1 1/4″) in fire-rated assemblies. So it does not even end up being "convenient," not that a 4" wall assembly is particulary more "convenient" than a 4.5″ or a 4.125″ or a 4.75″ wall assembly…very little turns on the thickness of the stud plus wallboard, but a lot turns on the thickness of the stud cavity (insulation, space for utilities, &c.) or the thickness of the drywall (spacing of electrical outlets, mudrings, etc.). [[User:JohnHawkinson|JohnHawkinson]] ([[User talk:JohnHawkinson|talk]]) 04:20, 7 September 2025 (UTC)
Once again, the UK wins on ridiculousness. I bought some fencing materials yesterday. The panels were 1.83m x 1.22m, so they could be metric but nevertheless 6' x 4'. I got some presawn posts that were 2400mm long (so kind of 8', or close enough), and they were sold as 75mm x 75mm, so they were 3x3, but they fit perfectly into the 70mm x 70mm post supports I got to go with them. Using metric to sidestep the need for traditional-measurement nonsense...but just keeping the nonsense and throwing new numbers at it. Actually, that should rendered into Latin and put on a scroll as part of a national coat of arms. [[User:Yorkshire Pudding|Yorkshire Pudding]] ([[User talk:Yorkshire Pudding|talk]]) 09:49, 7 September 2025 (UTC)

Since the tape measure uses variable length inches, the watch (provided by the cartoonist) might be similar to Vetinari's clock. (Where individual ticks are of random duration.) I looked to see if xkcd had covered such a clock before (for possible link), but didn't find one. [[Special:Contributions/2600:387:4:803:0:0:0:90|2600:387:4:803:0:0:0:90]] 19:16, 7 September 2025 (UTC)

As an aside, I am always bemused about Americans being so stuck on imperial measurements when metric is so much easier. Oh except money...Americans are happy with metric money :o). [[Special:Contributions/59.101.181.77|59.101.181.77]] 20:42, 7 September 2025 (UTC)
:Oh, undoubtedly. It's literally just counting. The system we all use for enumerating everything (including feet and inches, or furlongs and chains, or drachms and scruples, or whatever else) is base 10. So just use base 10 and give names to 1,10,100,1000, etc. of length/capacity/mass/etc. units, and nobody needs to know anything beyond counting to deal with absolutely everything. Anybody who says pounds and ounces, or yards and miles (or whatever) is superior is objectively wrong.

:But.

:People get used to things.

:So you get the mess I mentioned above.

:Adopt the metric system, but then sell milk in 568ml bottles, because that's a pint, and milk inherently belongs in pints, so people have to have that much milk as a unit. Sell syrup and treacle in 454g and 907g cans, so 1lb and 2lb cans of sugary stuff can still exist. Nobody would be able to cope with 400g, 450g, 500g, 900g or 1kg! Keep selling beer and cider in pints, but change spirits to 25ml or 35ml (which you choose is up to you as a licensed bar) from 1/6 of a gill (or 1/5 of a gill in Scotland). Sell fuel in litres, but advertise vehicle fuel consumption in miles per gallon. [[User:Yorkshire Pudding|Yorkshire Pudding]] ([[User talk:Yorkshire Pudding|talk]]) 22:59, 7 September 2025 (UTC)
:I know, obviously not {{wiktionary|the full shilling}}! [[Special:Contributions/92.17.62.87|92.17.62.87]] 23:16, 7 September 2025 (UTC)

::I will venture the hypothesis that folk in this conversation are not cooks. It's in the kitchen that the difficulties with the metric system are most frequently encountered. Many Imperial measures are factors of two; it's easy and intuitive to double something or halve something and have the result make sense, as several kitchen veterans have told me over the years, with varying degrees of irritation. A pound (16 ounces), half a pound (8), a quarter pound (4), yada. Too many halvings in the metric system, and you're into fussy decimals. Moreover, if the recipe calls for a pound of butter, and you feed it half a kilogram, thinking that's the metric equivalent and close enough, the biscuits/cookies ain't gonna come out the same, and folk are gonna come after you. I learned years ago to check the cup measure carefully to see if it was graded in ounces or milliliters, and whether the recipe it was supposed to be serving came from Yankeeland or Godzone. Or else. The metric system may be logically superior, but may not be practically superior in all contexts. It might be well to seek reasons, other than the usual dismissive ones, for why, for example, {{w|https://en.wikipedia.org/wiki/Metrication_in_Canada#Metrication_stalled|Canada took 15 years to fail to fully convert to the metric system}}.[[Special:Contributions/2605:59C8:160:DB08:F102:9332:DCBD:89C6|2605:59C8:160:DB08:F102:9332:DCBD:89C6]] 03:10, 8 September 2025 (UTC)
:::I very much ''am'' a cook, and that is, I'm afraid, nonsense. Cooking is the perfect example of why metric is better! A recipe written in imperial, or the almost-identical US Customary Units, doesn't work if you substitute a round number of grams in for it, no. Obviously. But that presupposes that recipes naturally occur in imperial, with conversion being necessary if grams are used. Plenty of recipes exist natively in metric though, and are a clumsy mess if performed in avoirdupois.

:::And "fussy" decimals aren't a problem. If you need to halve 325ml (for example), no recipe will be affected by your using 163ml instead of 162.5 – much as fluid ounce measurements aren't accurate to the half millilitre, millilitres don't need to be either. Being a Brit, I learned to bake bread in imperial because we're across two systems here, and were even more so when I was young, but I forced myself to change, because metric is, inarguably, vastly superior. Working with percentages of hydration when you're in fluid ounces of water and pounds of flour (or the entirely nonsensical volumetric cup system) is utterly ridiculous when you could just use numbers that are exactly equivalent to each other. 1kg of flour, at a 66% hydration ratio? Why, that'll be 660ml of water, which can simply be weighed into the bowl at 660g. Can pounds, ounces, pints, fluid ounces and cups do that? Very much no.

:::And your halveable measures are all well and good...if you're halving those particular numbers. Anyone can think of numbers that are easily halved though. But what if it's a 2 egg recipe with 3oz of flour, and you want to make 3 eggs' worth? Well, then you need 4.5oz of flour. A bit...fussy, no? Imperial and US-measure recipes feel like examples of pounds working neatly, because they've been constructed around easy-to-use quantities in that system. But metric recipes behave just as neatly, and are far more readily scalable, because the numbers are all just base 10, which everybody uses for everything all the time.

:::I know both. I can use both. I started out with imperial. But I choose to use metric, because metric is so very obviously superior. [[User:Yorkshire Pudding|Yorkshire Pudding]] ([[User talk:Yorkshire Pudding|talk]]) 15:17, 8 September 2025 (UTC)

::::See Technology Connection's latest video where he goes through a ridiculous series of imperial conversions to get from 192g of water to "about 0.2L".

Talk:3135: Sea Level

2025-09-03T22:38:03Z

80.189.2.17: Romans

Holy crud empty page! F1RST P0ST! [[User:RadiantRainwing|RadiantRainwing]] ([[User talk:RadiantRainwing|talk]]) 01:38, 30 August 2025 (UTC)
:2038: Last of the original Star Wars cast dies. —megan [[user talk:megan|talk]] [[special:contribs/megan|contribs]] 02:18, 30 August 2025 (UTC)
::What? If you're trying to get back at me because I was being useless and just "first posting", it's a reference to [[269: TCMP]], and I also, by the way, wrote the whole first paragraph of this explanation. [[User:RadiantRainwing|RadiantRainwing]] ([[User talk:RadiantRainwing|talk]]) 02:50, 30 August 2025 (UTC)
:::Alright, sorry, just realized what you did is a reference to [[493: Actuarial]]. Sorry about that! [[User:RadiantRainwing|RadiantRainwing]] ([[User talk:RadiantRainwing|talk]]) 02:53, 30 August 2025 (UTC)
::::I guess you're one of today's lucky [[Ten Thousand]]...
::::Wait, no, not everyone has read comic 493 by the time they're adults. I'm too lazy right now to calculate how many people learn about comic 493 each day, so I'll leave it as [[356|an exercise for the reader]]. —megan [[user talk:megan|talk]] [[special:contribs/megan|contribs]] 01:01, 31 August 2025 (UTC)
::::This is where it pays to have read every XKCD comic :P [[User:Logalex8369|Logalex8369]] ([[User talk:Logalex8369|talk]]) 16:45, 1 September 2025 (UTC)

This one is related to the [https://xkcd.com/2809/ Moon] comic. [[User:Pgn674|Pgn674]] ([[User talk:Pgn674|talk]]) 01:39, 30 August 2025 (UTC)
:Clearly. [[User:RadiantRainwing|RadiantRainwing]] ([[User talk:RadiantRainwing|talk]]) 01:49, 30 August 2025 (UTC)

Definitely easy to see, even the references are the same…Randall we trust in you not to copy again…《プロキシ》(XKCD中毒者) 19:07, 1 September 2025 (UTC)

::it's almost a repeat. is he running out of ideas? [[user:lett‪herebedarklight|raeb]] 09:54, 30 August 2025 (UTC)
:::Hope not. [[User:RadiantRainwing|RadiantRainwing]] ([[User talk:RadiantRainwing|talk]]) 16:56, 30 August 2025 (UTC)
:::Why do people talk about running out of ideas? That is something I can't imagine. The world throws ideas and absurdities at you all the time. Running out of time to execute an idea - sure. Seems much more likely to be filtering error (have to check current idea against 3000 previous strips). [[Special:Contributions/107.77.205.64|107.77.205.64]] 19:42, 30 August 2025 (UTC)

Larry Niven had a story about alien-made indestructible spaceship hulls, except the makers didn't account for tidal effects when grazing a star. The test pilot was nearly ripped apart, but figured a way to survive. He sued their butts off against the guarantee. He concluded that their home planet did not have a large moon, a Clue. --[[User:PRR|PRR]] ([[User talk:PRR|talk]]) 02:41, 30 August 2025 (UTC)
: Isn't it frakking ridiculous that the Puppeteers, with all their brains, haven't observed or couldn't deduce the existence of tides? I did like the deduction about their homeworld making them nervous and their legal system of blackmail/extortion, though. --DW [[Special:Contributions/2607:FB90:8FA9:E54A:5856:AACD:B913:6DD8|2607:FB90:8FA9:E54A:5856:AACD:B913:6DD8]] 13:59, 2 September 2025 (UTC)

I think I finally figured out the common thread. All the items here are here because they are elements of Life on Earth. The way the explanation was written kind of buried that important part of the comic.

Overall, if you just look at them as unrelated phenomena, then Lightning seems quite common. Islands made by microskeletons, and life-forms which change their form during development seem like they would be pretty common where there is life. Large tides - thought to be uncommon, but don't have much data, and models are hard. [[Special:Contributions/2600:387:4:803:0:0:0:A0|2600:387:4:803:0:0:0:A0]] 18:04, 30 August 2025 (UTC)

All planets with intelligent life we know have tides. In fact one could argue that tides play an important role in the development in life. Thus any intelligent observe is arguably familiar with tides. Thus the text is wrong in arguing that tides are surprising based on the observation that most known planets likely do not have large tides. --[[Special:Contributions/2A01:599:114:9E35:D827:C56:FF88:1858|2A01:599:114:9E35:D827:C56:FF88:1858]] 19:09, 30 August 2025 (UTC)

:Argument has problems - insufficient sample size, selection bias. Nothing in the comic talked about intelligent life.
:The role of tides in development of life certainly makes sense to add.
:Tides are strange in that they are very complex and hard to explain in detail. Fluid dynamics in a very complex, non-ridgid vessel, involve gravitational forces from multiple bodies. [[Special:Contributions/107.77.205.64|107.77.205.64]] 20:00, 30 August 2025 (UTC)

:: Sample size is definitely a problem. Nothing in the comic talks about tides being strange in a cosmic sense. They are just very weird for one of the two observers from earth. --[[Special:Contributions/195.63.76.62|195.63.76.62]] 20:39, 30 August 2025 (UTC)

::: Realistic. Early Romans had no experience of tides until they ventured out of the Medditeranean, and were probably as spooked by them as the observer here. [[Special:Contributions/80.189.2.17|80.189.2.17]] 22:38, 3 September 2025 (UTC)

:All planets with intelligent life that we know of also have microwave ovens and television cameras and rubber ducks. Perhaps those are also essential for the long-term continued existence of intelligent life? [[User:PotatoGod|PotatoGod]] ([[User talk:PotatoGod|talk]]) 19:09, 31 August 2025 (UTC)

::Well, I can confirm that microwave ovens are essential for the continued existence of this intelligent lifeform. [[Special:Contributions/159.118.184.96|159.118.184.96]] 04:47, 1 September 2025 (UTC)

I'm shocked that Randal didn't include some sort of reference to climate change- and how tides effectively, at least in 2025 and for the foreseeable future, dwarf sea rise due to melting ice. [[User:Seebert|Seebert]] ([[User talk:Seebert|talk]]) 20:18, 30 August 2025 (UTC)
:On a (twice-)daily basis, yes. But that's like saying an unseasonal/hyperseasonal cold snap belies the possibility of global warming. (If that's the point you're trying to make.)
:And I'm not sure if you're saying that Randall "is the sort of person who would go on and on about climate change, but for soe reason he surprisingly didn't do so here" or "he really ought to be mentioning climate change at every opportunity, but he missed the opportunity to convey the concept"..? I'd disagree with ''both'' of those assessments of his (non-)inclusion here, though, and perhaps you're even coming from a completely different third direction that I might or might not understand. But really not the place to discuss it, as he obviously hasn't made that part of the joke/message in this comic. [[Special:Contributions/92.17.62.87|92.17.62.87]] 23:27, 30 August 2025 (UTC)

Lightning should be common throughout the universe, as the ingredients for it (planetary atmospheres containing things like dust that can build up differential static charges through agitation) appear to be. It's still a very weird phenomenon, with many aspects not understood (how does the triboelectric effect work, can breakdown patterns be predicted, wtf is going on with sprites and ball lightning, etc) but it really isn't likely to be rare. --[[Special:Contributions/81.96.108.67|81.96.108.67]] 05:48, 31 August 2025 (UTC)

Ten feet tidal range on a remote island - isn't this too much? I thought it should be less, with stronger tides only in some gulfs where an amplification exists. https://en.wikipedia.org/wiki/Tide figure 15 shows 5 feet tidal range maximum
: In the channel tides can get pretty high and some parts of it would be remote islands by European standards. Also the comic doesn't mention remoteness. --[[Special:Contributions/195.52.138.253|195.52.138.253]] 18:42, 31 August 2025 (UTC)

Significant tides can also bother or surprise people who are used to comparatively smaller tides. I should know, I am one of those people. I live by the Mediterranean Sea and any time I go to the beach on the Ocean, I am worried that I will once again lose my towel to the moving shoreline... [[Special:Contributions/2001:861:51C2:B540:1593:36EE:75F9:1F83|2001:861:51C2:B540:1593:36EE:75F9:1F83]] 18:35, 1 September 2025 (UTC)

^V^ 8th place! Learning English lol…love autocorrect. in South Carolina, tides are HELL on coast《プロキシ》(XKCD中毒者) 19:05, 1 September 2025 (UTC)

Rolled over to tuesday and no new comic?? {{unsigned|SteveTheNoob|23:40, 1 September 2025}}
:It's still (as we write) Monday for Randall, even if it's ''slightly'' after midnight for some of us Rightpondians. And there are have definitely been more extreme 'delays' to the scheduled comics. Take a deep breath, man... If you have to go to sleep and wake up to the comic, then that's what you have to do... [[Special:Contributions/92.17.62.87|92.17.62.87]] 23:48, 1 September 2025 (UTC)
::I thought Randall would just publish using +00 timezone for the love of the game. Oh well, I’ll stay awake until he publishes {{unsigned|SteveTheNoob|00:40, 2 September 2025}}
:::It just varies so much. Sometimes it's "late afternoon 'tommorow'", for any given day, sometimes it has been so early, by ±0 UTC standards, that one wonders if he was effectively staying up to post it 'very late the night before'.
:::When he was on his book tour over this side of the Atlantic, I know at least some of them were 'sensibly' posted at times relative to his being in these time-zones (i.e. 5 or hours ahead of the non-'late' instances, usually.
:::Special comics (huge and/or dynamic ones) seem to be posted any time at all, at least by my possibly faulty combined recollection, which is perhaps due to last-minute tweaks (the lateness of April Fool comics is such that, whilst ''something'' is often posted, if 1/Apr is a M/W/F, it might have been an emergency-filler, or perhaps brought forward from the W/F/M following - and then days, or occasionally even a week or more, later, it happens).
:::It's only really possible, right now, to go into the edit history of various comics and see when they were uploaded by the BOT of the time (or, when BOTs have been temporarily or permanently broken, when a human editor decided it needed doing manually). This introduces some small polling-lag and response time between 'Randall time' and 'wiki time', but if you're eagerly awaiting the comic ''here'', that's probably the end-timing that most interests you.
:::I can't recall any "so late, it was almost Randall's tomorrow" instances, recently, but there was a "so early, it was not too long after his prior midnight". And if Randall ever uses an automated method of posting, I think it's only for exceptional circumstances (not noticably for individual strips, that is - things like the Time comic probably were automated-and-queued, out of planned necessity).
:::And you asked ''before'' 00:00 UTC (I restored the time... and used the Unsigned template as a quickish way to overcome you apparently not using <nowiki>~~~~</nowiki> properly), so even if he were of that habit, you were asking too soon. If he was supposed to be posting at 24:00 UTC, anyway. - Quickly checking, though, and he still hasn't posted as of this moment. But it's still only late evening on Monday, where he is, and has maybe a couple more hours to spare before it becomes notably (and maybe fashionably) late. If you're under UK or one of the EU timezones, that's a long time to wait up. Not sure even ''I'' should be here, right now, though I do have my 'reasons' for it.
:::No, still no change on xkcd.com, just checked before I signed it off. Whether you'll get more or less sleep than myself, I leave up to your circumstances, possibly your other morning commitments. But I'm expecting to see the Monday comic in a few hours, when I check, even though that'll be actually the start of my own Tuesday. [[Special:Contributions/82.132.239.156|82.132.239.156]] 02:00, 2 September 2025 (UTC)
:The new comic is out now, although I don't think explainXKCD has updated yet.[[Special:Contributions/47.150.145.249|47.150.145.249]] 04:46, 2 September 2025 (UTC)

Not sure the premise of this comic is correct. The sun generates tides on Earth of about half the amplitude of the tides generated by the moon, and those vary on close to the same period. Tidal force is proportional to rM/R^3, where r is the radius of the planet experiencing the tide, M is the mass of the body creating the tide, and R is the distance between them. Something like Gliese 581c is 6.8 times the mass of Earth, and assuming comparable density, would have r = 1.9 times the Earth. The star Gliese 581 is 0.3 times the mass of our Sun, and the planet orbits at R = 0.07 that of earth. So we have 1.9 * 0.3 / 0.07^3, a star-induced tidal force on Gliese 581c of more than 1600 times that of the Sun on Earth, and more than 800 times that of the Moon on Earth. So, while large moons near a planet might be uncommon, those aren't the only sources of tides comparable to those on Earth.[[Special:Contributions/163.116.145.92|163.116.145.92]] 17:00, 2 September 2025 (UTC)

As we're still mentioning Pluto-Charon, just need to properly point out that (regardless of planethood), its moon is ''so good'' at causing tides, on Pluto's actual hard-mass, that Pluto would now not experience cyclic tides ''anything like'' Earth's twice-daily version. It's perhaps a bit anthropocentrically-expdriential, but we could say that Earth's sweet-spot of tides lies between those of moons too small+distant to create notable tides and those so large+near that they've dominated the 'planet' into a situation where tides are meaningless. (Ditto other twin-dwarf-planets out there.) 
We also have an oceanic, but land-studded, surface; pretty much without precedent on any other body that we know sufficient information about. Tides on Titan (by Saturn, i.e. planet-on-moon) can't do quite so much with its methane 'lakes', Tides on Europa (by Jupiter) can at most flex the icy shell over its substantial water-ocean with no 'land' to flood/reveal. Which might well each produce interesting alternative tide-related effects, to the tides as ''we'' best known them, but very much not the same thing. (Titan, in particular, seems to have possible dominating 'seasonal' transference of liquid from hemisphere to hemisphere, but not by a tide-type mechanism. Any nominal Titanians would perhaps be used to that change of local shorelines, but still be mystified/surprised by ''our'' tides. What potential Europans might think is even harder to say, as we have even less unambiguous understanding about what ''their'' home-experience is, like if there's any 'spires' of base rock that reach significantly up the local column of liquid-water to make the icy shell movement a notable effect. And our world would already be considered strange enough to their 'eyes'.) [[Special:Contributions/82.132.238.108|82.132.238.108]] 18:24, 3 September 2025 (UTC)