explain xkcd - User contributions [en]

Talk:3181: Jumping Frog Radius

2025-12-16T14:37:40Z

Bismuthfoot:

first[[User:Qwertyuiopfromdefly|Qwertyuiopfromdefly]] ([[User talk:Qwertyuiopfromdefly|talk]]) 05:17, 16 December 2025 (UTC)

Question: Would a correct interpretation be "if a champion jumping frog were to be located just under 1.5 light-days from earth, and if there we're no other gravitational bodies nearby, and if said frog then performed its mightiest jump directly away from earth, then the frog would eventually be overcome by Earth's gravitational field and would eventually land on Earth's surface"? [[User:Pgn674|Pgn674]] ([[User talk:Pgn674|talk]]) 06:26, 16 December 2025 (UTC)
:I guess that is exactly how it should be interpreted. Or more interesting if it was just outside this radius and somehow could gain exactly 4,5 m/s extra speed then it would escape Earth (if there was anything to push of against that was heavy enough to move basically only the frog forward, then that would change the mass behind the frog so... That was why I wrote gain exactly rather than jump). --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 07:36, 16 December 2025 (UTC)

: or its mightiest jump in any direction (that doesn't cause it to crash through the Earth) since the escape speed is the same in all directions (relevant xkcd:https://what-if.xkcd.com/68/ ) --[[Special:Contributions/178.197.223.163|178.197.223.163]] 09:21, 16 December 2025 (UTC)

The only two variables are rjf and M, so plotting a 2 axis graph plotting the relationship between M and rjf should be possible. [[User:Zabadoh|Zabadoh]] ([[User talk:Zabadoh|talk]]) 08:20, 16 December 2025 (UTC) [''You sign '''after''' your contribution'']

As frogs usually collect on the surface of worlds {{cn}}, the *surface* escape velocity is most important. The crossover point for a planet with earth-like density (5515 kg/m³) is 2.6km, above that, the rjf falls below the surface, and the planet can accumulate frogs. Smaller bodies are, however, usually less dense; an interesting borderline candidate is Chicxulub, which had an rjf of 3-4km, and a radius of 5-6km so could have just about held onto its frogs, for a while at least. [[User:JeffUK|JeffUK]] ([[User talk:JeffUK|talk]]) 10:04, 16 December 2025 (UTC)

It would be interesting to look at the Rjf values ''of a frog'', to consider where new limits are put upon the frog for M-masses that aren't totally dominating the scenario of "frog leaves mass"... [[Special:Contributions/82.132.237.93|82.132.237.93]] 11:03, 16 December 2025 (UTC)

I interpreted it as a reference to the Mark Twain short story The Celebrated Jumping Frog of Calaveras County.
[[User:Gustaveeiffel314|Gustaveeiffel314]] ([[User talk: Gustaveeiffel314|talk]]) 12:25, 16 December

I also suspected an allusion to Twain's short story, but then I read it at archive.org/details/celebratedjumpin00twai and found no parallels. The earth's radius wasn't the problem, it was 5 pounds of quail shot. That frog didn't land with a "plop" but "as solid as a gob of mud." There is no mention of "champion" in the story. The 1865 population of Calaveras County (post Gold Rush) was down below 15,000. That is, the frog shown in #3181 probably came from somewhere else that really knows how to breed frogs with muscular legs, maybe France. Before I risk overthinking this, I'm going to conclude that #3181 is not a Twain reference. [[User:Bismuthfoot|Bismuthfoot]] ([[User talk:Bismuthfoot|talk]]) 14:37, 16 December 2025 (UTC)

Talk:2929: Good and Bad Ideas

2024-05-07T17:47:58Z

Bismuthfoot:

Lots of bread/food in the "good" quadrant; I think Randall is hungry. [[Special:Contributions/162.158.154.73|162.158.154.73]] 05:33, 7 May 2024 (UTC)

Soup always seems like a very good idea to me. I guess I like soup. --[[Special:Contributions/172.69.79.182|172.69.79.182]] 07:15, 7 May 2024 (UTC)

I remember something like this in what if. [[Special:Contributions/SectorCorruptor|SectorCorruptor]] 07:21, 7 May 2024 (UTC)
:The title immediately reminded me on the Animaniacs shorts "Good Idea / Bad Idea" [[User:Elektrizikekswerk|Elektrizikekswerk]] ([[User talk:Elektrizikekswerk|talk]]) 07:33, 7 May 2024 (UTC)

Does anybody know why solar cars and transitions lenses are actually a bad idea? [[Special:Contributions/172.70.160.173|172.70.160.173]] 09:11, 7 May 2024 (UTC)
:Transitions lenses are misplaced. The only caveat is that if you like outdoor photography (landscapes, wildlife, etc.) you should get grey lenses rather than brown ones, because the brown ones make a blue sky seem overcast. [[User:Pjt33|Pjt33]] ([[User talk:Pjt33|talk]]) 09:22, 7 May 2024 (UTC)
::The precise opposite is true. Grey lenses make ''all'' things - blue sky included - look greyer, as is perhaps unsurprising. Brown tints involve a degree of orange, which means the overall impression is of a "warmer" colour pallette, rather than simply a duller one. There is a reason that "grey skies" and "overcast" mean ''exactly'' the same thing - an overcast sky ''is'' a grey tinted filter. [[User:Yorkshire Pudding|Yorkshire Pudding]] ([[User talk:Yorkshire Pudding|talk]]) 09:48, 7 May 2024 (UTC)
:I think the Transition lens issue is primarily that the bright light that can turn them dark need not be heading into the eye. With the Sun (say) off at an angle, it could be 'reacting' your lenses to dark needlesly, and reducing your ability to discern the things in front of you (which may be in shadow), working against the basic ability of the eye to adjust itself as per observed illumination.
:Conversely, a small bright light would not sufficiently darken the lenses but be still damaging to the spot(s) it falls upon in your retina (or do the "whole lens go dark" thing and ''still'' be too bright even as you can't see anything else beyond it). This might also be combined with the general secondary problem of potentially all regular sunglasses/goggles, that aren't industrial-grade or specific solar-specs, in that it might make it ''look'' safe to stare at bright things/skies through them but you cannot tell how much UV/etc is also being filtered out (some brands do have notable UV protection, but you really have to trust their claims/certifications – unless you have your own testing kit and knowledge of how much is good/bad anyway).
:I'd add that, but it needs a sharper explanation than I just gave. I'd like to make what's already there snappier, before that, plus correct the numerous typos and funny formatting (and lack of useful wikilinks), but will probably leave that to others with the time. [[Special:Contributions/172.71.242.204|172.71.242.204]] 10:08, 7 May 2024 (UTC)

Just as a note while we're here: "fecal transplant" is one of the most spectacular branding failures in the history of medical science, in my opinion. I mean, don't put the word "fecal" in anything you want people to feel positively about. And "microbiome transplant" is sitting right there, ready to serve.[[Special:Contributions/108.162.242.37|108.162.242.37]] 10:44, 7 May 2024 (UTC)

Double plug cords are VERY MUCH a bad idea. Used mostly to plug generators into an outlet to power a house, it tends to harm people working on the power lines who were not expecting them to be charged when the power was out. The statement about them being hard to use, is quite the understatement. OSHA, written in blood. [[Special:Contributions/172.70.115.103|172.70.115.103]]

How can soup be bland? There are bland soups, spicy soups, sweet soups, savory soups ... you can't call an entire very broad category of food "bland" like that. It makes no sense.[[User:Nitpicking|Nitpicking]] ([[User talk:Nitpicking|talk]]) 11:46, 7 May 2024 (UTC)
:I think they may have meant bland as in boring, not tasteless. I'll tweak it. [[User:Barmar|Barmar]] ([[User talk:Barmar|talk]]) 16:20, 7 May 2024 (UTC)

Citation format needed. (heelies) {{unsigned ip|172.70.178.103|12:57, 7 May 2024}}
:''Summary: (I don't know how to format correctly.)'' - no, you don't...
:For a link to an external URL, writting <code>[the_url]</code> will give you a "linked number", but a better format is using <code>[the_url text to replace]</code> (with a space betwixt the URL and the text that will link to it. e.g. [https://google.com a link to google] from <code><nowiki>[https://google.com a link to google]</nowiki></code>.
:There are full on citation/reference methods, but mostly I wouldn't bother with <nowiki><cite> and <ref> tags</nowiki> at all.
:Internal links, with [[]]s, and template-based ones, with {{}}s (e.g. the nicely-linking shortcut to wikipedia pages), use a pipe (the "|") between the sections. But you should be able to work that out by looking at what is already in the edit-source.
:If in doubt, Preview your intended change and see if it looks right. I'll let you correct your contribution. Or whoever else wants to shake up the whole article, as it has multiple problems from spelling mistakes to inconsistent style to repeating information and it needs a lot of rationalising that I can't even think of doing right now. [[Special:Contributions/172.69.195.113|172.69.195.113]] 14:09, 7 May 2024 (UTC)
::I didn't realize we actually have no citation templates. Quite a few pages have the actual citation needed template but not many of them ever get those citations. I think a lot of citations get put in just as external links. I probably should've done that but I was like oh I know how to do this from my small amount of Wikipedia editing, I'll just use the cite web template... oh we don't have that. So rather than just do an ad-hoc link I created the citation in my Wikipedia sandbox then manually recreated the formatting. But now it feels weird and out of character for this wiki so maybe someone should just change it to a link. idk, maybe being inconstant is exactly what is in-character for this wiki. [[User:Brycemw|Brycemw]] ([[User talk:Brycemw|talk]]) 15:10, 7 May 2024 (UTC)

As a Columbus native, I am HIGHLY offended by this anti–rectangular pizza slice speech. Rectangular pizza is by far the BEST shape that a pizza can be. (I'm not really offended, but I really do think rectangular pizza is superior.) [[Special:Contributions/108.162.216.229|108.162.216.229]] 14:04, 7 May 2024 (UTC)
:Sicilian pizza should be square and cut into square slices, Neapolitan pizza should be round and cut into sectors. The extra thickness of Sicilian means you don't eat it by holding the crust and folding, so the shape of the slices is less critical. But this does mean that the middle slices have no crust around the edges. [[User:Barmar|Barmar]] ([[User talk:Barmar|talk]]) 16:25, 7 May 2024 (UTC)

Leaded gasoline isn't to reduce *noise*. The noise is a symptom of detonation (aka knock), which is the real problem. Knock is caused by pressures and temperatures high enough and for long enough to detonate the fuel/air mixture (as opposed to the deflagration initiated by the spark plug at a set time), and can result in engine damage. Leaded gasoline (through complicated chemistry) increases the pressure/temperature required to get that detonation, and thus allows the engine to be designed to run at higher temperatures and compression ratios, which is where the efficiency improvements come from. [[Special:Contributions/172.70.39.41|172.70.39.41]] 14:38, 7 May 2024 (UTC)

Maybe, cross-reference "Sliced bread" to [[1065:_Shoes]] and [[1885:_Ensemble_Model]] (with sliced bread in both comic and title-text).

Talk:2743: Hand Dryers

2023-02-28T04:16:54Z

Bismuthfoot: thought about Covid's role in air dryer reputation.

The mouseover text is trolling, since that would be impossible. [[Special:Contributions/172.70.200.140|172.70.200.140]] 16:23, 27 February 2023 (UTC)
:Indeed, Randall wrote about that in ''How To 2''. [[User:Nitpicking|Nitpicking]] ([[User talk:Nitpicking|talk]]) 03:49, 28 February 2023 (UTC)

The Pratt & Whitney J58 is capable of producing exhaust velocities exceeding that of Mach 2 at ground level. It would be possible (though extremely inadvisable) to dry one's hands in the exhaust, at least for the brief period where one still has hands. [[Special:Contributions/172.70.115.72|172.70.115.72]] 16:44, 27 February 2023 (UTC) J. Kupec

With a low enough vacuum in the surrounding area, a supersonic hand dryer should be able to apply drying without enough energy dissipation to damage the skin. [[Special:Contributions/172.69.65.184|172.69.65.184]] 17:27, 27 February 2023 (UTC)

As far as I understand it, the low velocity dryers heat the air, the high velocity ones don't, but rely on the air being compressed and air speed is of the essence. The other problem with the idea of very high speed is that 'stuff' could penetrate the skin (there is a type of needle-less vaccination gun on that principle).[[User:RIIW - Ponder it|RIIW - Ponder it]] ([[User talk:RIIW - Ponder it|talk]]) 19:31, 27 February 2023 (UTC)

That matches my memory, the first ones I remember were fairly low airspeed and had a data tag "1500 watts" for the heating element. Has anyone tried one of these with *dry* hands, to see how long the element takes to get hot? I don't think they heat up instantly. They certainly get hot--motorcycling on cold days I've pointed the nozzle inside my clothing to warm up at a rest stop.[[Special:Contributions/172.70.111.76|172.70.111.76]] 19:40, 27 February 2023 (UTC)

I don't think this effect fully explains observations. For example, the airflow feels warmer sooner when someone has used the dryer just before you. [[User:P1h3r1e3d13|P1h3r1e3d13]] ([[User talk:P1h3r1e3d13|talk]]) 21:10, 27 February 2023 (UTC)

"though this was first achieved many decades ago, in the 1950s" Yeager broke the sound barrier in level flight on Oct. 14, 1947, and planes had been doing it in dives for years. [[User:Cser|Cser]] ([[User talk:Cser|talk]]) 21:29, 27 February 2023 (UTC)
:Without reading your comment, I further changed the (as it was for me) "1940s" version of the statement to include the original "inadvertent" barrier-breaking (of prop-planes in almost always irrecoverable dives, without control surfaces that would work well in supersonic/transonic airflows) and included the developments made, which these days are somewhat more trivial than having to sit on a rocket that is released from a high-altitude bomber's wing, and fight to keep it flying straight and level. (We even had a supersonic airliner, for several decades!) There's a lot of interesting history to this, but not really the place to say it all. [[Special:Contributions/172.70.85.57|172.70.85.57]] 01:45, 28 February 2023 (UTC)

Should we make an "airplane banner" category? [[Special:Contributions/172.70.111.76|172.70.111.76]] 02:31, 28 February 2023 (UTC) I was thinking the same thing, but I'm here about Covid (below).

Hand dryers were disabled in the early days of Covid in 2020 before hand transmission was ruled out as significant. I still feel awkward using one in a bathroom with others. I'm old and still mask when indoors publicly more than briefly. In 2023, I submit that you risk appearing hypocritical with a mask and a hand air dryer. Thus, I saw this XKCD as a reminder that hand air dryers had nothing to do with Covid. Still, there seems to be a bunch of fuss about the dryers. Apparently, some use mechanical air force (jet air) more than warm air for drying, from respectable gavi.org and wired.org in 2021 (https://www.gavi.org/vaccineswork/we-know-hand-dryers-can-circulate-germs-through-air-why-are-they-still-used and https://www.wired.com/story/wash-your-hands-but-beware-the-electric-hand-dryer/). I'm just rambling here; I'm not ready to do any editing. [[User:Bismuthfoot|Bismuthfoot]] ([[User talk:Bismuthfoot|talk]]) 04:16, 28 February 2023 (UTC)