explain xkcd - User contributions [en]

Talk:3023: The Maritime Approximation

2024-12-12T00:09:43Z

162.158.186.248:

1.609*3.1416926 looks like 1.852*2.718281828
''seems legit'' {{unsigned ip|172.71.124.233|21:37, 11 December 2024 (UTC)}}

I added the basics of an explanation, it definitely needs some work, but it should do as a starting point. Hope I did well! [[Special:Contributions/172.68.22.92|172.68.22.92]] 23:06, 11 December 2024 (UTC)

The knot is exactly 1 nautical mile per hour. Meanwhile π/e ≈ 1.155727, which is close to nm/mi = kt/mph ≈ 1.15078
[[Special:Contributions/172.70.134.135|172.70.134.135]] 23:26, 11 December 2024 (UTC)

This article says one knot is 1.2 MPH, which is true for the number of digits of precision stated. But in context of the claimed precision of 0.5% it would be more helpful to state that one knot is approximately 1.151 MPH. https://en.wikipedia.org/wiki/Knot_(unit) [[Special:Contributions/172.71.159.7|172.71.159.7]] 00:08, 12 December 2024 (UTC)

Transcendental : relating to a spiritual realm. eg "the transcendental importance of each person's soul". Works for me.

Talk:3001: Temperature Scales

2024-10-24T05:21:02Z

162.158.186.248: 0.1694×C+46.27?

Shouldn't Rankine say "0ºR is set to absolute zero"? {{unsigned ip|172.70.230.29|22:58, 21 October 2024 (UTC)}}
:Yep. [[Special:Contributions/162.158.186.253|162.158.186.253]] 04:38, 22 October 2024 (UTC)

yo,i thought comic 3000 was anticlimactic so randall would make this one COOL but sadly not
Same. Hope he does something cool for 3072.[[Special:Contributions/172.69.134.225|172.69.134.225]] 23:44, 21 October 2024 (UTC)

really he didn't do anything special for this either? come ON randall if you don't do something cool for comic 3072 i will come to your house personally and yell at you [[User:RadiantRainwing|RadiantRainwing]] ([[User talk:RadiantRainwing|talk]]) 23:57, 21 October 2024 (UTC)

 
What's random about Fahrenheit? (Answer: nothing.) 0F is the freezing point of brine, 100F (or 98.7) is the human body temperature. [[Special:Contributions/172.68.54.65|172.68.54.65]] 00:00, 22 October 2024 (UTC)
:What concentration of brine? (And which specific salt... No, not NaCl, as you might presume but NH4Cl!)
:And body temperature varies a lot ('typically' 36.5–37.5°C or 97.7–99.5°F, though even this range is thought to be too small), across genders, individuals, time of day ''and'' which orifices/surfaces you try to measure it from. (Originally, it was set so that '''90°F''' was to be the 'best guess' of human body temperature. It gradually changed, including via various {{w|Human body temperature#Historical understanding|compounded misunderstandings}} so that the best you can say is that 100°F is arbitrarily ''slightly above'' most afebrile human body temperature measurements.)
:Celsius might be a bit off (arguments about triple-point or STP freezing, etc), but it still has far more physical logic to it. [[Special:Contributions/172.70.160.188|172.70.160.188]] 01:14, 22 October 2024 (UTC)

Sorry, Randall, for my comfort, Fahrenheit is the least cursed. It's the best scale to use for my personal use, especially when hearing the weather report and deciding what to wear outdoors: temp in the 80's - no jacket. temp in 70's - maybe a windbreaker if it's breezy. 60's - sweater weather. 50's - medium weight coat. 40's - winter coat. 30'3 - winter coat with scarf and gloves. 20's - multiple layers. teens - stay indoors. None of the other scales provide such convenient distinctions for my daily life. Kelvin is great for astro physics or super conductivity, but useless for any common uses. Celsius is great for hanging out with the Euro crowd but still not so useful to scale my home thermostat. I judge Fahrenheit as 1.0 for cursedness. [[User:Rtanenbaum|Rtanenbaum]] ([[User talk:Rtanenbaum|talk]]) 14:19, 22 October 2024 (UTC)
:I conveniently use Celsius in tens, also. Negative °C: Cold; 0-10°C: Nippy; 10-20°C: Generally pleasant; 20-30°C: Too warm to exert oneself; 30°C+: ''Definitely'' too warm. [[Special:Contributions/172.70.86.205|172.70.86.205]] 15:24, 22 October 2024 (UTC)

Personally, I'm most disappointed that {{w|Delisle scale}} was not represented... [[Special:Contributions/172.70.160.188|172.70.160.188]] 01:14, 22 October 2024 (UTC)
: I was so hoping for a {{w|Planck temperature}} quip. Like: "Water freezing point: 0; Water boiling point: 0; Notes: 1 = highest possible temperature (1.4E32K) where thermal radiation creates black holes; Cursedness: 0/0" [[Special:Contributions/162.158.164.184|162.158.164.184]] 01:27, 22 October 2024 (UTC)
:: Same here. Freezing is 0.000000000000000000000000000001928 and boiling is 0.0000000000000000000000000000026338. [[User:DanielLC|DanielLC]] ([[User talk:DanielLC|talk]]) 03:38, 22 October 2024 (UTC)
::: Wow, those are even smaller than the IEEE floating point representations of 1-1.0/3*3! [[Special:Contributions/162.158.90.109|162.158.90.109]] 03:59, 22 October 2024 (UTC)
:: The Planck temperature quip is definitely well deserved. Good catch! [[User:Mumingpo|Mumingpo]] ([[User talk:Mumingpo|talk]]) 17:24, 23 October 2024 (UTC)
I guess I was wrong in my comment on the last comic. sigh. -[[User:Psychoticpotato|P?sych??otic?pot??at???o ]] ([[User talk:Psychoticpotato|talk]]) 01:16, 22 October 2024 (UTC)

It's actually spelled {{w|Wedgwood scale}}, not Wedgewood. [[User:Wilh3lm|Wilh3lm]] ([[User talk:Wilh3lm|talk]]) 01:17, 22 October 2024 (UTC)

I still call the modern version of the "Celsius" scale "centigrade", but if people start nitpicking, I'm happy to switch to "Carolus" to avoid ambiguity. For some reason that tends to annoy people more though. [[Special:Contributions/172.68.22.191|172.68.22.191]] 01:32, 22 October 2024 (UTC)

Every temperature scale is equally "random" as every other scale. People always say that Celsius is so much better because it's defined by the phase changes of water. Okay, cool...why should THAT of all things be what we use as the base for a system of temperature measurement? And, who cares? I'm a ''Homo sapiens'', not a water molecule. If anything we should use the freezing and melting points of humans as our two reference points for temperature (which, I must say, Fahrenheit approximates better than Celsius, assuming 0 and 100 are your points "A" and "B"). [[User:Pie Guy|Pie Guy]] ([[User talk:Pie Guy|talk]]) 03:42, 22 October 2024 (UTC)
: Every temperature scale is arbitrary, but since boiling and freezing water is a thing humans have a lot of experience with it makes sense to use that as the reference point. At least it makes more sense than whatever the coldest recorded temperature in Fahrenheit's home town was, because he didn't like negative numbers [[Special:Contributions/172.70.250.23|172.70.250.23]] 03:56, 22 October 2024 (UTC)
::Planck temperature (as above) is probably the least arbitrary, and some would say it is to some extent free from arbitrariness. However, it's completely impractical for everyday use (as above.) [[Special:Contributions/172.69.34.138|172.69.34.138]] 04:31, 22 October 2024 (UTC)
:::Do the physics of black holes or neutron stars involve Planck temperatures greater than 0.0000001? [[User:Liv2splain|Liv2splain]] ([[User talk:Liv2splain|talk]]) 07:23, 22 October 2024 (UTC)
::::Chat Gippity told me:

:::::Black holes and neutron stars do not typically involve temperatures reaching the Planck scale. While both objects exhibit extreme physical conditions, their temperatures are far below the Planck temperature, even though they can be incredibly high compared to everyday phenomena.

::::: - **Neutron stars** have surface temperatures in the range of millions of Kelvin, and the core can reach even higher, possibly up to a few billion Kelvin. These temperatures are still vastly lower than the Planck temperature.

::::: - **Black holes**, especially the smaller ones, can emit Hawking radiation, with temperatures inversely proportional to their mass. However, the temperature of even a very small black hole is still far below the Planck temperature. Hawking radiation is not expected to reach temperatures close to the Planck scale under normal circumstances.

::::: The Planck temperature (TP=1) represents an energy scale so extreme that no known physical models, including those describing black holes and neutron stars, operate near or above this threshold. Temperatures reaching **0.0000001 TP** (or 1.416 × 10^26 K) would still be beyond current observational and theoretical frameworks related to these cosmic objects. A quantum theory of gravity would be required to describe physics at or near the Planck temperature, which remains speculative and is far beyond the conditions found in black holes or neutron stars.

::::[[User:Liv2splain|Liv2splain]] ([[User talk:Liv2splain|talk]]) 08:46, 22 October 2024 (UTC)

If the °X scale is based on the temperatures of Earth from all time (for some definition of "Earth"), then the scale is very hard to define and highly impractical. The earth appears to have gotten to more than 2,300 Kelvin (hot enough to melt steel and platinum and to boil lead) and while I can't find any sources for the lowest temperature, I imagine it is lower than -100°C. The recorded minimum, maximum and average temperatures appear to be around -89.2 °C, 56.7 °C and 15 °C respectively. This would make the scale somewhat useful, but this would make typical values between 41 °X (cold winter's day) and 68 °X (hot summers day) which I think is pretty cursed. I recommend the clearly superior °Y, based around average temp at 0 °Y, low at -100 °Y and high at 100 °Y. These would be measured by the yearly high, low and mean temperatures averaged per person. Then saying "It's 2 times colder than yesterday" would have some reasonable meaning. --[[Special:Contributions/198.41.236.147|198.41.236.147]] 04:01, 22 October 2024 (UTC)
:"''Record'' ... surface temperature" implies it was recorded. [[Special:Contributions/172.68.22.9|172.68.22.9]] 04:08, 22 October 2024 (UTC)

How do you all feel about adding an additional column for room temperature 22C/72F?
{| class=wikitable style="text-align:right;"
! scope="col" | Unit
! scope="col" | Room temperature
|-
| Celsius || 22
|-
| Kelvin || 295
|-
| Fahrenheit || 72
|-
| Réaumur || 18
|-
| Rømer || 18
|-
| Rankine || 531
|-
| Newton || 7
|-
| Wedgwood || -7
|-
| Galen || 0
|-
| ''Real'' Celsius || 78
|-
| °X || 59
|}

Or 0.00000000000000000000000000000208 °Planck, lol. [[Special:Contributions/108.162.245.211|108.162.245.211]] 05:36, 22 October 2024 (UTC)
:I feel like decigalens would be the most practical unit. Who's with me? [[Special:Contributions/162.158.186.5|162.158.186.5]] 06:20, 22 October 2024 (UTC)
::It's interesting; calculating the equilibrium temperature (with 2.05 and 4.24 being used for the heat capacities of ice and boiling water) gives 67... If I use water that's about to freeze and steam, I get 31. [[Special:Contributions/172.69.0.178|172.69.0.178]] 07:59, 22 October 2024 (UTC)
:::Would you please explain in more detail? [[User:Liv2splain|Liv2splain]] ([[User talk:Liv2splain|talk]]) 09:03, 22 October 2024 (UTC)
:::: The equilibrium temperature of a mixture (?) of equal quantities of ice at 0 C and water at 100 C (with the heat capacities 2.05 and 4.24) is 67 C; if I use the data for water at 0 C and steam, I get 31 C. Additionally, if I use equal volumes, I get 68 (which isn't much different.) [[Special:Contributions/172.69.0.178|172.69.0.178]] 17:15, 22 October 2024 (UTC)
:::: One can obtain 0 = 22 C by setting the heat capacity of ice to be 39 and that of water to be 11. For any particular "normal temperature" ''R'' °C (that is, the temperature at 0 is ''R'',), I find that ''x'' °C = 50''R''(''x''+4)/(''x''(''R''-50)+200). In particular, for ''R'' = 22, we get (1100+275''x'')/(50-7''x''). [[Special:Contributions/198.41.236.163|198.41.236.163]] 05:58, 23 October 2024 (UTC)
::How about 0.1694×C+46.27, where 0 is absolute zero and 50 is room temperature? [[Special:Contributions/162.158.186.248|162.158.186.248]] 05:21, 24 October 2024 (UTC)

Question regarding the X scale - when it‘s defined by *three* (somewhat, implying average is real and not just calculated by (max-min)/2)) independent points, how will linearity be achieved? [[Special:Contributions/162.158.155.76|162.158.155.76]] 05:43, 22 October 2024 (UTC)
[[File:Explanation length.png|right|thumb|Or click "[Expand]" in the bottom right table cell Derivation.]]
:Please see [[2701: Change in Slope]]. [[Special:Contributions/172.70.206.179|172.70.206.179]] 05:50, 22 October 2024 (UTC)
:Sure, "a linear scale between each point":
[[File:XvsC.png|thumb|left|Here you go. [[User:Liv2splain|Liv2splain]] ([[User talk:Liv2splain|talk]]) 06:33, 22 October 2024 (UTC)]]
{{clear}}

The reference for the average surface temperature, https://www.space.com/17816-earth-temperature.html, suggests it has increased above 15°C. What value should we use in late 2024? [[User:Liv2splain|Liv2splain]] ([[User talk:Liv2splain|talk]]) 07:30, 22 October 2024 (UTC)
:The [https://wmo.int/media/news/earth-experiences-warmest-day-recent-history World Meteorological Organization], [https://www.carbonbrief.org/state-of-the-climate-2024-now-very-likely-to-be-warmest-year-on-record/ Carbon Brief], and [https://climate.copernicus.eu/new-record-daily-global-average-temperature-reached-july-2024 Copernicus Climate Change Service] suggest 17.16°C. [[User:Liv2splain|Liv2splain]] ([[User talk:Liv2splain|talk]]) 07:42, 22 October 2024 (UTC)
::Updated water temperatures, Derivation, and graph. So we've already had more than the +2°C warming we were trying to avoid in 2019? [[User:Liv2splain|Liv2splain]] ([[User talk:Liv2splain|talk]]) 08:05, 22 October 2024 (UTC)
::: The +2°C (or +1.5°C that we were originally supposed to be avoiding) is over some (undefined) number of years, though, which allows us to ignore the fact that we're cooking ourselves by repeatedly saying 'Oh, but it doesn't count ''yet''.' [[Special:Contributions/172.70.91.62|172.70.91.62]] 11:13, 23 October 2024 (UTC)
Regarding [https://www.explainxkcd.com/wiki/index.php?title=3001%3A_Temperature_Scales&type=revision&diff=353635&oldid=353632], are the average surface temperatures from the sources supposed to be yearly or overall averages? [[User:Liv2splain|Liv2splain]] ([[User talk:Liv2splain|talk]]) 09:06, 22 October 2024 (UTC)
:According to https://climate.copernicus.eu/climate-indicators/temperature the global average near-surface temperature in 2023 was 14.4 + 0.4 = 14.8°C. (see Figure 1 and click "Increase above: [1991–2020 reference period].") [[Special:Contributions/172.68.22.8|172.68.22.8]] 21:06, 23 October 2024 (UTC)

where is the interactive epic 3000 comic we should've gotten? This one's cool but 1000 seemed to have more effort in it and 2000 was at least tangetially related. Does Randall just not like making these anymore and is only making more comics as a business? [[Special:Contributions/108.162.238.185|108.162.238.185]] 12:14, 22 October 2024 (UTC)
:The comic is free on the website and it doesn't have ads; although the comic is part of his "brand" there are many more profitable things he could be doing with his time, and yet he continues to update it every Monday, Wednesday, and Friday. I just don't like the idea of claiming that a creative person "should" produce any particular thing to satisfy their fans. He's a busy guy! Maybe he's working on a book, or a Scientific American article, or a TV show. He's under no obligation to give us anything, and maybe one day he'll stop making xkcd altogether; that's his choice. Sorry to single you out; I know a lot of people feel the same way as you do, but to me it doesn't make sense. He's not a content machine--he's a guy who started posting sketches on the internet. [[User:Dextrous Fred|Dextrous Fred]] ([[User talk:Dextrous Fred|talk]]) 15:23, 22 October 2024 (UTC)
::Sorry if I sounded overly brash, I wasn't trying to imply "wahhh no special entry wahhh", I was just wondering if Randall still likes to make these or if he doesn't, mainly because he just didn't do anything special, which feels like he just didn't care. I wasn't trying to imply Randall should just do it for the fans[[Special:Contributions/108.162.238.80|108.162.238.80]] 17:52, 22 October 2024 (UTC)
:::It ''could'' be that 3000 (or even 3001) ''was'' going to be special but, as fairly frequently with April Fool 'specials', it just wasn't doable on time. (If it's still considered fixablez it might pop up sometime before 3020 or so. Or, if transferable to another occasion (rebranding the obvious "3000!"ness), held over until Haloween, Christmas, April or 4000, perhaps with additional perfections.)
:::Hard to know, unless Randall (or his technical collaborators) say anything. And it's probably not worth doing so right now. Maybe "Hey guys, this ''was'' going to be #3000!" might accompany its eventual emergence, but also maybe not. Does it really matter? [[Special:Contributions/172.70.85.139|172.70.85.139]] 13:03, 23 October 2024 (UTC)

Is this the first list-style comic where every single entry is real? (Usually he has several joke entries.) [[Special:Contributions/172.70.114.182|172.70.114.182]] 14:26, 22 October 2024 (UTC)

Where would [[1923: Felsius|Felsius]] go on this list?

One can find a smooth function for °X, namely, (477879''x''-17634840)/(3341''x''+197700), which takes °X and returns °C. The inverse is (-197700''x''-17634840)/(3341''x''-477879). Should this be included in the wiki article? Or maybe another way of fitting it (like exponential) should be used. [[Special:Contributions/172.69.0.165|172.69.0.165]] 06:27, 23 October 2024 (UTC)
:It says "a linear scale between each point". [[Special:Contributions/172.70.210.130|172.70.210.130]] 21:09, 23 October 2024 (UTC)

Should it be noted that in the first _What If?_ book, there's a reference to units and how much Randall loathes rankine? Someone can go take the book and cite it; it's in one of the early pages [[Special:Contributions/172.64.236.10|172.64.236.10]] 08:45, 23 October 2024 (UTC)

I remember it being drummed into us in school physics (admittedly over 50 years ago) that 0 Celsius is defined as the melting point of ice, not the freezing point of water (presumably because of supercooling). [[Special:Contributions/172.70.160.189|172.70.160.189]] 08:49, 23 October 2024 (UTC)

It seems he wrote "Earths'" (plural possessive) instead of "Earth's". [[Special:Contributions/141.101.98.151|141.101.98.151]] 08:58, 23 October 2024 (UTC)

What? No gas mark? It's linear for temperatures over 275°F but inverse powers of 2 below That's pretty cursed, but I still put it in my unit conversion app. It's only used in gas stoves in a few countries, so it doesn't come up very often. By the way, boiling is 1/5.7358 and freezing/melting is 1/843.3572. Interestingly, France has it's own stove temperature scale that seems to be based on °F.

Also, my understanding is that 7.5 and 32 aren't random. Both Romer and Fahrenheit put numbers on things so that freezing/melting of water and "Normal human body temperature", which was thought to be standard at the time, would be some number X (15 for Romer and 64 for Fahrenheit) and the water thing would be to be X/2 and NHBT would be X/2+X. Pretty nerdy. Sadly, the calibration was off and 212 degrees for boiling was found to be less cursed. But I could be wrong.[[Special:Contributions/172.68.54.138|172.68.54.138]] 20:39, 23 October 2024 (UTC)
:Re: water/ice point 'random number', I think it's more that it wasn't considered "special", such that "On my scale, that will be zero" (or whatever choice of handily round number, including zero, some scale-setters allocated to the BP of water).
:After all the other messing about ("my zero will be that of brine!", etc), obviously then the ~0°C equivalent would ''have'' a number, and ''perhaps'' there would then be a slight change to make it a ''whole'' (or easy-fraction) number for convenience's sake, but (before the concept of binary computers) there's not much special about landing on the number 32, for what is actually a temperature that is quite significant to the human experience, and less so with 7-''and-a-half''.
:Maybe landing on 90°F (at one time) for body temperature (and 180 F° ''between'' MP and BP) was considered useful as the analogue to angular-degrees where 90 (and 180) indeed features significantly, but I don't think there'd have been too much fuss if the value would have turned out to be 60(/120), also with plenty of handy factors to divide by, 70(/140), without so much, or whatever number(s) happened to depict one realistic real-world measurement that (overall) has no reason to have a factor-based relationship with various quite separate phenomenon measurements.
:''And'' it went through several {{w|Human body temperature#Historical understanding|'corrective' iterations}} so that even its handy relationship with 'about 100°F' can be said to be an incidental accident, at best, unless we do something like Randall's °X scale and actively triple-tie the central value of the slope(s) to be exactly something useful by using the "currently accepted mean human body temperature (given various complicated caveats)".
:It's pretty much all random, in the same way that only because of anthropocentric choices of 'standard' time and distance measurements is the speed of light 'pretty much' 3×10⁸ m/s (a handily round value that works well enough for most purposes, even after back-standardising its component SI measurements to make "actually, precisely 299792458" the ''proper'' answer, and [https://conversion.org/speed/speed-of-light/furlong-per-fortnight it could be far worse...]). Avagadro's number never had it so good (6.022(+change)×1023...? ...where's the handily mnemonic value in that?), and Pi (in this universe's system of fundemental mathematics) clearly never ever had a chance! And, on {{w|Mount Everest#19th century|at least one occasion}}, such happenstance numeric roundedness in its exactitude (29''',000''' ft) was considered actually quite awkward... [[Special:Contributions/172.70.91.90|172.70.91.90]] 21:33, 23 October 2024 (UTC)

Ok, then, regarding {{diff|353895|this edit}} (and the original IP-led one(s) that even made huge and revert-necessary changes), was it ''really'' intended to get rid of whole paragraphs such as "Randall also fails to specify what happens with temperatures[...]" that had nothing to do with the numeric adjustments? When I see that, I see mistakes (especially in light of the "clobber" that happened, where typos reappeared and other things became unexplained/worse-explained once more). — Basically, if your edit summary is nust about updating baseline data, and the resulting maths, I don't expect (maybe good, maybe bad) edits to unrelated bits. Or I may (and have) presumed accidental (or deliberate?) carelessness that I'd rather not try to go back to first principles to re-re-check for the editor concerned. That is all. At least try to justify enough of your edit in its own way, even if it means diving in several times to get enough space to summarise your whole "why" to each tweak. [[Special:Contributions/172.68.186.104|172.68.186.104]] 22:44, 23 October 2024 (UTC)
:Yes. I have re-removed the removals piecemeal with individual edit summaries for clarity. Many of them involved detailed obscure technical misunderstandings, such as whether the Vostok and Death Valley measurements were surface temperatures (the WMO says they are, and there are the WMO's photos of the observation stations in the linked references now) which combined with the incorrect yearly average global mean temperature, added five paragraphs unnecessarily. [[Special:Contributions/172.68.23.152|172.68.23.152]] 01:46, 24 October 2024 (UTC)
::Definitely some points made (some incorrect, "ne er" was ''obviously'' more just a basic typo of "never", not my attempt to use "ne'er" for no good reason, and my attempt to fix that and some other bits ran into a set of Edit Conflicts ...hope I caught all the remaining ones when I finally could try again on the settled-down page) and I've blended answers to your objections in while giving back what useful nuances (from a number of past editors, only a couple of bits even having had my own hand primarilly behind them as they were) really needn't have been removed. I dispute the terms of your objections (as summarised) behind {{diff|353937|some changes}}, but have rephrased based upon what I ''think'' you mean, giving you should prefer and wouldn't feel the need to be as randomly censorious about. [[Special:Contributions/172.69.195.173|172.69.195.173]] 02:54, 24 October 2024 (UTC)
:::Figure 1 in https://climate.copernicus.eu/climate-indicators/temperature does not seem like a random walk to me. [[Special:Contributions/172.69.33.118|172.69.33.118]] 05:02, 24 October 2024 (UTC)

== Division by zero ==

I saw this in an edit summary: "10/0 is not ∞, it's also an error, not NaN according to the IEEE. It's closer to {+∞, -∞} than NaN but it's still neither because you can't make limits work"

Actually, IEEE floating point 10/0 can be an error, +∞, or NaN depending on the rounding mode. This is one of the reasons why mathemeticians don't appreciate the IEEE as much as they might. Division by zero is strictly undefined because of the problems with limits alluded to in the summary. https://www.youtube.com/watch?v=dHdg1yn1SgE [[Special:Contributions/108.162.245.66|108.162.245.66]] 03:48, 24 October 2024 (UTC)

Talk:2974: Storage Tanks

2024-08-23T08:29:05Z

162.158.186.248: reply

The symmetry of the truss intrigues me. Struts that are diagonal across the faces of the cuboids is normal, but is it a real thing to also use the body diagonal? Never seen that IRL, not sure if it makes sense from the statics. --[[Special:Contributions/172.70.247.82|172.70.247.82]] 22:16, 19 August 2024 (UTC)
: Struts as shown provide some left-right stability, but not as effectively as struts across the face would. They also provide some redundant front-back stability with the struts running along the faces. [[Special:Contributions/172.68.71.90|172.68.71.90]] 14:47, 21 August 2024 (UTC)
: I mentally modeled the flexibility modes, and it very much depends upon whether the verticals are solid (with their resistence to bending playing a big part alongside the incident horizontals'/diagonals' exactvmethod of attachment) or are just sections of rod between a suitable receiver-'node' at each junction.
: in particular, the strength of any one of the three 'boxes' (each level between adjacent horizontal cross-sectional perimeters) is somewhat less secure, as a single level can 'fold' sideways over each side's vertical-diagonal strut (along with the respective front/back horizontals, held 'square' by the internal cross-brscing). Only the continuation and linking with the other 'boxes' really guarantees any innate stability, and if each node is free-twisting then the likely first result of any failure is that the tower topples forwards and/or backwards as it folds up due to the unbraced facing and hindside quadrilaterals.
: But it does depend a lot upon the exact nature of the linkages (which can only be guessed at), and other failure-modes could involve node-slippage if they merely grip the cross-braces to the entirely top-to-bottom poles and there's potential for sliding there instead of primarily rotation (or over-stressed failure in any given length of rod).
: The support (or additional pressure) provided by the access staircase is also probably a factor. It could even be the most important bit in holding it up! ...if firmly anchored at the other end and robust enough in itself.
: I'd definitely add other diagonals (including opposite-type body-diagonals, perhaps tied to the existing one as they pass right across each other), just to be sure. The more the better, of course, but there's probably a limit through diminishing concerns. And too many diagonals primarily in a helical pattern could concentrate forces into a particular type of rotational failure if you also add too much brace-weight in doing so. [[Special:Contributions/172.70.163.120|172.70.163.120]] 15:07, 21 August 2024 (UTC)

Seems like a pretty menial job for the "head of security". I think he would delegate this to a security guard. [[User:Barmar|Barmar]] ([[User talk:Barmar|talk]]) 00:47, 20 August 2024 (UTC)
: They may be head of a department of one.[[Special:Contributions/172.70.85.139|172.70.85.139]] 08:50, 20 August 2024 (UTC)
:: That's part of the joke, that the #1 concern of the Head of Security is calculus teachers wielding power drills for class demonstrations. [[User:Laser813|Laser813]] ([[User talk:Laser813|talk]]) 17:33, 20 August 2024 (UTC)

The explanation mentions there might be more complex calculus examples where the shape might not be a cylinder. I think some further explanation could be added that this does not change the pressure (hydrostatic paradox) but indeed change the rate of emptying the object. If differing cross sections are relevant at all. [[Special:Contributions/108.162.221.103|108.162.221.103]] 05:40, 20 August 2024 (UTC)
: Non-prismatic geometries are I think the ones being alluded to here, i.e a frustrum with the pointy end down will have a greater reduction in pressure for a given volume of flow towards the end than at the start, which may offset the reduction in absolute pressure. I've also seen examples where the flow rate is considered constant and the problem is to work out the fluid depth as a function of time, e.g. filling a pyramidal pool from a hose. [[Special:Contributions/172.70.58.4|172.70.58.4]] 16:44, 20 August 2024 (UTC)

Its the most difficult job in history, even the best workers couldn't stand 1 day as head of security.[[User:I HAVE NO NAME|I HAVE NO NAME]] ([[User talk:I HAVE NO NAME|talk]]) 05:55, 20 August 2024 (UTC)

I have to admit, I thought I knew calc as I had two semesters of it, but I had to look up what he meant by this. Ouch [[Special:Contributions/172.70.242.55|172.70.242.55]] 13:01, 20 August 2024 (UTC)student

If anyone could suggest something I can do for my class now that I can no longer drill holes in tanks, I'd appreciate the advice, thanks. [[User:Fephisto|Fephisto]] ([[User talk:Fephisto|talk]]) 16:18, 20 August 2024 (UTC)

Someone should do the math on the calculus problem as presented, as well as the algebra version. [[User:Laser813|Laser813]] ([[User talk:Laser813|talk]]) 17:33, 20 August 2024 (UTC)
: Randall, like all good mathematics textbook authors, left the problem as an exercise for the reader. Does this happen often enough to warrant a tag? [[User:Paddles|Paddles]] ([[User talk:Paddles|talk]]) 05:57, 21 August 2024 (UTC)
:: Yes... [[User:Transgalactic|Transgalactic]] ([[User talk:Transgalactic|talk]]) 10:10, 21 August 2024 (UTC)

Is there anyone else who thought the calculus teacher was abusing the tank as a model for the complex plane, demonstrating how to [https://en.wikipedia.org/wiki/Removable_singularity remove a singularity] from a holomorphic function by puncturing the plane? I wasn't confronted with that particular tank-emptying problem in high school, so my first encounter with "holes" in maths was in complex analysis. The title text was a mystery. [[User:Transgalactic|Transgalactic]] ([[User talk:Transgalactic|talk]]) 10:10, 21 August 2024 (UTC)

As a mathematician, I'm surprised I didn't know about this idea. (It's definitely not my field!) I actually thought the flow would be constant, an algebraic problem. Oh, I'm sure I saw these types of problems in Calculus (and I remember problems like this in Differential Equations), but I thought those were just to make the math more complicated, not based in reality... So is it the weight of the liquid remaining above the hole that is the source of the pressure (i.e., would it be the same if the top of the tank were open), or is it the air pressure in the tank as the volume of liquid decreases and volume of air increases? [[User:Mathmannix|Mathmannix]] ([[User talk:Mathmannix|talk]]) 11:08, 21 August 2024 (UTC)
:A sealed-top would change the dynamics (like trying to pour the contents of a 2 litre (or whatever the US equivalent is) pop/soda bottle, it will tend to 'glug glug glug' intermittently unless you: a) incline the bottle to allow an optimum amount lf free akr back into the emltying bottle or, b) initialise the up-ended emptying with a spin sufficient to create a 'waterspout' effect up through which the replacement air can (more) freely pass.
:Though there are other possible factors, in that example, including the potential pressure of any self-releasing carbonation pressure (e.g. giving the bottle a shake, or a foreign body, before releasing the 'pour') and/or squeezing/'milking' the soft plastic container strategically to create another form of pressurised expulsion.
:For the 'classical' problem, one should probably assume sufficient inward venting (either an open/part-open top or a second hole drilled near the top to effect this purpose) as well as a reasonably unexotic liquid (neither molasses, cornstarch-mixture, anything that is actually a very fine dry powder, anything that reacts significantly with/upon air, any liquid very close to its vapour-point nor ''specifically'' supercooled helium) or any additional elements (stirrers, baffles, spongey inners, inner membranes or the contents being a layered combination of imiscable liquids of different densities that may or may not react slightly all across the interface plane). Most things that aren't actually exotic (and even a few that are, and might warrant a warning /¡\) are close enough to water to treat as if just that, at least under the further assumption that we're working at or around Standard Temperature and Pressure. But a slightly different density, viscosity and surface tension (plus the nature of the container, e.g. extreme hydrophilic or hydrophobic inner coatings where water is involved) ''could'' (in combination) drastically change the actual outcome given enough of the right kind of simultaneous differences imparted. [[Special:Contributions/172.70.86.37|172.70.86.37]] 14:28, 21 August 2024 (UTC)
::We have these at my work: https://shop.snydernet.com/images/snyder-6370721n95402.pdf The viscosity is a huge deal, unless you can afford to waste a bunch of supply. [[Special:Contributions/162.158.186.248|162.158.186.248]] 08:29, 23 August 2024 (UTC)

In order to remove calculus from the scenario one needs a pressurization system that keeps Pair + Pliquid, constant at the hole. This requires sensing the height of the liquid surface and increasing the air pressure as the surface drops, the relationship depending on the density of the liquid. [[User:Mjackson|Mjackson]] ([[User talk:Mjackson|talk]]) 22:02, 22 August 2024 (UTC)

Talk:2964: Olympic Sports

2024-07-27T19:56:49Z

162.158.186.248: furthermore

What took bro so long
Is he stupid [[Special:Contributions/141.101.98.119|141.101.98.119]] 13:05, 27 July 2024 (UTC)
:Seems totally unclear what you're referring to, here.
:[[User:ProphetZarquon|ProphetZarquon]] ([[User talk:ProphetZarquon|talk]]) 15:00, 27 July 2024 (UTC)
::i think they're referring to this comic being somewhat late. [[user talk:lettherebedarklight|youtu.be/miLcaqq2Zpk]] 15:07, 27 July 2024 (UTC)
:: The comic appeared around 0800 EDT 20240727 (Saturday, a day late). As most folks here surely know, late posts are common on xkcd but aren't often later than the stated "MWF". After 19 years, and without the "weeks ahead" buffer insisted upon by "traditional" syndicated comics (as shown by [https://xkcd.com/2961/ Crowdstrike], posted the day of the event), I think Randall has done remarkably well. I'd struggle to keep a schedule like this for 19 weeks.[[Special:Contributions/172.71.151.95|172.71.151.95]] 15:34, 27 July 2024 (UTC)

I think "''Synchronized'' Swimming" would be the most hilarious. One person flailing while a whole team tries to make it look choreographed.
[[User:ProphetZarquon|ProphetZarquon]] ([[User talk:ProphetZarquon|talk]]) 15:00, 27 July 2024 (UTC)
:I picture two people that are synchronized to each other while the third person tries to look choreographed - [[Special:Contributions/162.158.212.172|162.158.212.172]] 15:11, 27 July 2024 (UTC)
:Why must I think of "The fox has left his lair"... [[Special:Contributions/172.71.160.71|172.71.160.71]] 16:39, 27 July 2024 (UTC)

I hear there's an opening on the GB equestrian team. Just sayin'...
[[Special:Contributions/141.101.69.119|141.101.69.119]] 19:15, 27 July 2024 (UTC)

I'm going to disagree about a couple. Beginning pole vaulters are incredibly funny. Beginners on the pommel horse aren't usually very funny. [[Special:Contributions/162.158.186.252|162.158.186.252]] 19:54, 27 July 2024 (UTC)

Talk:2871: Definitely

2023-12-23T16:28:07Z

162.158.186.248:

Regrettably for someone who has mild dyslexia, and with it in All Caps, I have difficulty seeing the subtleties of the spellings. [[User:RIIW - Ponder it|RIIW - Ponder it]] ([[User talk:RIIW - Ponder it|talk]]) 09:08, 23 December 2023 (UTC)
:Seems intentional; it would be less funny if the typos were more obvious?
:[[User:ProphetZarquon|ProphetZarquon]] ([[User talk:ProphetZarquon|talk]]) 13:40, 23 December 2023 (UTC)

I have defiantly left this typo as-is, on purpose, before.
[[User:ProphetZarquon|ProphetZarquon]] ([[User talk:ProphetZarquon|talk]]) 13:40, 23 December 2023 (UTC)

I buffed up the Explanation (basically replaced it, the editor-suggestions for 'other not-wrong-honest spellings' didn't fit. Maybe I should transplant that down here as a game for us all to play 'aside' from any Explain). Some phrasing or language I can see being ripe for going under the scalpel/wrecking-ball of the next editor to arrive here, but I think it's a decent framework that covers most of the points. Just the one thing I nearly added, but left off, was actually going into the various Word-Meaning pairs. I can imagine why some of the Meanings are used (seem to have a sense that aligns with the letter-jumble that makes the Word wrong), but not enough to do a full table about it (as an obvious attempt at over-analysis). But if anyone else has a yen to do so then... Just remember that I thought of it first. ;) [[Special:Contributions/141.101.99.59|141.101.99.59]] 16:14, 23 December 2023 (UTC)
: You beat me to it. I was unable to ascertain any way to link clues in the misspellings to the meanings assigned to them, and I think that the meanings were haphazardly, even absurdly, assigned. [[Special:Contributions/162.158.186.248|162.158.186.248]] 16:28, 23 December 2023 (UTC)