Talk:Temperature

why manifolds

There are a few references to manifolds in this article, i.e. "Hotness may be represented abstractly as a one-dimensional manifold." In this context, it seems like this introduces unnecessary jargon, and is less precise: there are only two one-dimensional manifolds, the circle and the real line, and hotness is represented abstractly as the real line, not the circle.

Before making this change, I want to check in with people that I'm not missing some historical reason to use the term manifold here--my background is in math, not physics. ProboscideaRubber15 (talk) 00:09, 13 February 2022 (UTC)

Hi @ProboscideaRubber15:. The literature contains discussions of temperature in terms of a hotness manifold. I haven't thought much about this, but I guess that so-called 'negative temperatures' can be seen as residing in the circle.Chjoaygame (talk) 15:57, 28 August 2022 (UTC)

How is the real line a two-dimensional manifold? 81.225.32.185 (talk) 22:10, 15 September 2023 (UTC)

Temperature scales

This section is very confusing, redundant, and probably erroneous...

All physically reasonable temperature scales are related by affine relations of the form T' = a T + T0. I believe the article should only mention the Fahrenheit and Celsius "relative scales" (i.e. defining a 1° difference) and the Kelvin scale (absolute zero at 0, same 1° difference than Celsius). The reader should understand that °C or °F are 2 definitions of ° difference, with their respective offsets, and that K is like °C up to an offset. Olivier Peltre (talk) 09:17, 28 August 2022 (UTC)

Hi @Olivier Peltre:. Thank you for your concern. Yes, the article is overloaded with part repetition, and even confusing, and could do with improvements. If you find things in it that are "probably erroneous", please identify them, settle whether they are actually or just probably erroneous, and get them corrected, all by use of reliable sources. Quite likely there are erroneous things in the article. Much in Wikipedia is erroneous.

Perhaps all "physically reasonable" temperature scales would be of the form $T^{\prime }=aT+T_{0}$; indeed, I suppose that all physically reasonable absolute temperature scales are so. But by that criterion, there are notable temperature scales that are "physically unreasonable". In particular, there is no general way of relating empirical temperature scales precisely affinely to the absolute scales. Material thermometric properties are often nearly but rarely precisely so. Much practical thermometry is empirical.

There are many notable temperature scales beyond the SI, Kelvin, Celsius, and Fahrenheit.Chjoaygame (talk) 15:36, 28 August 2022 (UTC)

Too talky

This wikipage is way too talky and mentions a lot of irrelevant stuff. Is it really necessary to include a graph of the human body temperature over the course of a day and various temperature scales before giving a formal definition and description of what temperature comes from?

I added the thermodynamical definition in the intro and consider moving/deleting several sections that feels like word fillers. 81.225.32.185 (talk) 21:48, 15 September 2023 (UTC)

• Sorry, but I undid your edit: I think there was a formatting error, it messed up the layout of the intro, and I don't see the point of that highly technical thing in the lead. Drmies (talk) 21:51, 15 September 2023 (UTC)
  • I think at least one proper definition is suitable. Compare with the article on momentum. It starts with: "In Newtonian mechanics, momentum (PL: momenta or momentums; more specifically linear momentum or translational momentum) is the product of the mass and velocity of an object." It isn't unreasonable to demand one sentence with a more scientific definition. 81.225.32.185 (talk) 21:56, 15 September 2023 (UTC)
    • A sentence is fine, but that's not really what you wrote. Drmies (talk) 22:26, 17 September 2023 (UTC)

Are all temperature measuring devices "thermometers"?

@Remsense: re: [1] Despite the etymology of "thermometer", there are temperature measurement devices or temperature sensors not commonly called thermometers. This is supported by the table of contents of the following textbooks:

• Temperature Measurement and Control [2]
• Principles and Methods of Temperature Measurement [3]
• Temperature Measurement [4]
• Temperature Measurement [5]

Especially temperature imaging devices, such as satellite temperature measurement sensors, are not commonly called "thermometer". A thermometer onboard a satellite would be understood as measuring the satellite body temperature. Likewise, "thermal imaging" could have been called in principle "imaging thermometry", but it's not normally done so. If we don't agree on this, then temperature measurement should be nominated for merging into thermometer, for consistency. See previous related discussion: Talk:Thermometer#Distinction_between_thermometers_and_temperature_sensors. fgnievinski (talk) 01:02, 18 November 2023 (UTC)

I would be fine with a phrasing such as "temperature measurement devices, such as household thermometers." Remsense聊 01:55, 18 November 2023 (UTC)

There may be some confusion about the physics here. Satellites don't measure temperature directly. They do not use temperature sensors, except for monitoring themselves. Instead they measure incoming radiation at various wavelengths and, assuming a model of how the radiation is produced by the radiating body, calculate the temperature. For stars this is a fairly simple process. For measuring temperatures on earth from a satellite this can get quite complicated. The temperature determinations are done back on earth.

There are many names for scientific thermometers. Using a table of contents that lists types of devices by name rather than calling each a thermometer doesn't support your argument. The third book link has 6 chapters titled by type of thermometer. Thermocouples, for example, are in the chapter titled "Thermoelectric thermometers". These are followed by three chapters on pyrometers, which measure incoming radiation and convert that to temperature. While I would call just the first thermometers, with the advent of handheld remote infrared sensor devices such as those that became popular during the epidemic, some of the pyrometers are known as infrared thermometers. Industrial models are now called radiation thermometers. I would say that any device that reads out a result as temperature is considered a thermometer. If the output is radiation readings that need computer processing elsewhere, then it isn't a thermometer. But that is just my opinion on where the field is going.

Temperature measurement is a rather strange article. It starts out as the process of measuring a current local temperature for immediate or later evaluation, then has a section on satellite temperature measurements. I would not merge the articles. Not all determinations of temperature are done using thermometers. It could be rewritten into the top-level article on the subject. StarryGrandma (talk) 14:25, 18 November 2023 (UTC)

As for the sentence in the lead paragraph, I suggest "measured with a thermometer or by other means." This is comprehensive enough that it covers any sort of device or method of determining temperature, including those model-dependent satellite measurements of the earth's temperature. StarryGrandma (talk) 20:52, 19 November 2023 (UTC)