Talk:2292: Thermometer

Explain xkcd: It's 'cause you're dumb.
Revision as of 16:29, 13 April 2020 by (talk) (0.02€ for thermodynamics and neutron diffraction)
Jump to: navigation, search

First non-Covid post other than April fools? 23:04, 10 April 2020 (UTC)

Since a fever is a common symptom of Covid-19, I'd say this is as much about Covid-19 as all the previous comics on the topic. Ianrbibtitlht (talk) 02:59, 11 April 2020 (UTC)
I'd disagree. Fevers aren't inherently related to COVID-19, and while it's certainly easy to draw a connection based on current events, at no point is the connection made explicit. 10:29, 11 April 2020 (UTC)
Seriously? Fever is associated with 88% of COVID-19 cases! I'd say that's inherently related, and I'm drawing a connection based on that fact. Ianrbibtitlht (talk) 12:59, 11 April 2020 (UTC)
Fevers are associated with almost all infectious diseases. By that logic, this could be about the flu, mono, or a hundred other conditions. Shamino (talk) 17:24, 11 April 2020 (UTC)
I, too, think calling this a Covid-19 comic is excessive. Sure, thermometers for measuring body temperature are sold out at my local drugstore, and pandemic likely inspired the comic, but if it had been published a year ago, we wouldn't infer any connection to a specific disease or global epidemic. - Ada in New Hampshire, USA 07:56, 12 April 2020 (UTC)
I would assume anything that can be linked, even loosely, is probably part of this chain. I have been assuming since the 6th one that Randel would aim for 19 of these just because. Though perhaps he will keep going till the hype is over. Either way, requiring that it directly mentions the topic it was inspired by would be way overkill. Mentioning things that likely inspired a comic is something we have done for a long time, and the virus seems like the most likely inspiration, especially when taking the full comic chain into account172.69.198.52 21:33, 12 April 2020 (UTC)
The comic doesn't mention a fever. For all we know Cueball is trying to measure the outside air temperature, or how hot his coffee is. We can rule out the idea that he is trying to measure the temperature of some liquid helium only because he skipped past the kelvin scale. Jeremyp (talk) 18:39, 12 April 2020 (UTC)

A common practice in schools and the like prior to quarantine was temperature taking upon arrival. So it's like that this comic continues that to the home setting. 23:19, 10 April 2020 (UTC)

A pessimist would guess that this means someone in Randall's household has a fever. 23:26, 10 April 2020 (UTC)

> The Physician Ducks172.69.62.94 23:32, 10 April 2020 (UTC)

Personally I'd welcome a home thermometer marked off in Kelvin, avois all the "twice as cold" sort of confusion you can get with an arbitrary zero as used in Celsius and Fahrenheit. 23:21, 10 April 2020 (UTC)

I might have enjoyed a "Degrees of Kevin Bacon" joke in this comic somewhere. :-) 23:42, 10 April 2020 (UTC)

Double-plus-dissapointed we didn't get the Delisle measure referenced at all... 01:17, 11 April 2020 (UTC) ...and now added. It would be better in any Trivia section, but we don't have one so hoping it's no more out of place in the explanation as Fahrenheit. 02:02, 11 April 2020 (UTC) ...aaaand someone removed it (as pure trivia, of course), fair enough. Anticipated. Anyone still interested in what I put just needs to check this IP, at about this timestamp, in Page History, though, so not going to argue the point. 02:08, 11 April 2020 (UTC)

No temperature scale is defined using melting or boiling points of water anymore. Since 2019 Kelvin is defined via the Boltzmann constant, and all other temperature scales have been (re-)defined relative to the Kelvin scale for quite a while. -- 01:24, 11 April 2020 (UTC)

Randall forgot the Réaumur scale. 03:00, 11 April 2020 (UTC)

I'm not sure why some people seem to look for any opportunity to take a dig at the US, but I removed the line in the explanation about US-based readers not being familiar with the Celsius temperature scale. I'm sure most Americans are familiar with it but prefer the Fahrenheit scale instead. I don't understand why anyone holds that against us. Ianrbibtitlht (talk) 03:04, 11 April 2020 (UTC)

Hey, let's assume good faith. Chances are, some rando just genuinely had no idea how that kind of stuff works here. 10:22, 11 April 2020 (UTC)

Regarding USA Fahrenheit and non-USA Celsius preference, I was in Niagra Falls a few years back, listening to a Canadian station on the radio (ok, more than a few years ago...) and the DJ gave a weather report, saying “The current temperature is 25 degrees, that’s 77 on the understandable scale.” 04:22, 11 April 2020 (UTC)

I guess if you wanted to use the Newton scale you'd need to have Newton's original "degrees of heat" measuring device. 04:31, 11 April 2020 (UTC)

Nitpicking alert : the correct writing is "kelvin", not "Kelvin".

100°F is "really hot"? Maybe on a stripper... 13:00, 11 April 2020 (UTC)

Also nitpicking: "Kelvin" is correct, as it is a name like Fahrenheit (,_1st_Baron_Kelvin or as you like...)Tier666 (talk) 14:59, 13 April 2020 (UTC)

Randall, as a physicist, should know about the equipartition theorem. It states that all degrees of freedom will carry the same average amount of energy in thermal equilibrium, not only the translational kinetic ones (but also rotational, and potential energies). It is technically not false to exclude some of these, but an arbitrary choice. I guess he just wanted to include the terms “translational” and “kinetic” to make sure it sounds ridiculously over-specific (which works well). 15:07, 11 April 2020 (UTC)

No, it's still an important distinction. Many Thermometers can only 'measure' the average Translational energy and the rotational and elastic energy is just assumed to match that. (The only Thermometers that measure rotational and elastic Energy are the ones who only measure their own temperature... which is 99.5 of all consumer Thermometers.) And it probably does except in some very specific cases with ultra high speed pressure changes.
Let's be scientific and [up things] before asserting false claims. Energies are not “assumed to match”, but it is the very core of Boltzmann's statistics that they have no other choice than doing so (that's one of the consequences of the second law of thermodynamics). That's why it is sufficient to know the first moment of any of the energy distributions to know about the thermal budget (definition of temperature). The way how thermometers measure temperature in practice is a totally different topic (take liquid thermometers: they exploit thermal expansion aka anharmonicity of inter-molecular potential energies). 16:29, 13 April 2020 (UTC)

+Using the average Translational Energy would would sidestep all the problems with the different units of temperature and would also eliminate the necessity of using the Boltzmann constant, simplyfying a lot of physics. But nobody wants to make the transition since most everyday temperatures would be between 5 and 8zJ, with 5 being freezing, six being tolerable and seven a desert at noon. The Unit, Zeejays would sound cool though. 09:30, 13 April 2020 (UTC)

Alternatively, use molar mean disordered translational kinetic energy per mole, making the numbers nicer by a factor of Avogadro's number, and bringing the scale to 2-3kJ/mol. Or add in a factor of 1.5 as well to make the gas K.E. formula simpler. Sqek (talk) 10:27, 13 April 2020 (UTC)
Eww, nobody likes (or uses) SI units in atomic physics. Contrary, electron-volts are a totally common measure of temperature. Think of the typical 25 meV of thermal neutrons off a research reactor. You literally see temperature (diffraction patterns on detectors), their De Broglie wavelengths are just in the inter-atomic distances range that makes them perfect diffraction probes of molecular/crystalline structure (weren't there these nasty radioactivity issues). 16:29, 13 April 2020 (UTC)

Well, it has Fahrenheit after a fashion. Just substract 460 from Rankine. It's even easier than converting Kelvin to Celsius!

I find it much quicker to subtract 0.01C° 27,315 times than to subtract 0.01F° 45,967 times, personally. I think you're quite barmy to suggest otherwise, Unsigned... :P 16:17, 11 April 2020 (UTC)
Now that I, the formerly Unsigned, think of it, I must agree with you - but for an entirely different reason. 273.15 in binary is a nice, round 100010001.001(00101) with 3 1's in the integer and 4+2n 1's for every 3+5n fractional digits, whereas 459.67 is much messier: 111001011.10110001111110... , with 6 1's in the integer alone. The more 1's there are in a number, the more operations you have to do for each addition or subtraction. So in binary, Kelvin-to-Celsius is much easier to convert than Rankine-to-Fahrenheit. Yet another point in favor of the glorious metric master system, da? Osato (talk) 19:57, 11 April 2020 (UTC)

I removed the weasel words, indicating that Fahrenheit is "generally appreciated" because 0 means very cold and 100 very hot. I adjusted it to "some claim" and adjusted the text to fit.

Make the scale in Celsius 0 to 200, and I think you would have a system much more relatable to Fahrenheit users.

I can imagine a worse scaling system! Base it on Cat-Scratch-Fever, Hot-Blooded, Yellow Snow, SpringTime in Alaska, Beds are Burning, Burning Down the House . (not in that order) Cellocgw (talk) 12:49, 13 April 2020 (UTC)

By a strange coincident, I went for a walk to the real Rømer's Observatorium Tusculanum today (full details in the Danish wiki). If you like Historical Science, it's worth a visit next time you're in Denmark... --Fod (talk) 16:25, 13 April 2020 (UTC)