Talk:Conversion of scales of temperature

Delisle to Fahrenheit conversions (and vice versa)

Please note that the current conversion from the Delisle scale to the Fahrenheit scale is currently: [°F] = 121 − [°De] × 6⁄5 and the Fahrenheit to Delisle conversation is: [°De] = (121 − [°F]) × 5⁄6
These equations do not give the correct temperatures, the "121" should be "212". I did not check the Delisle conversation to other temperature scales, but it might be worth checking. I am pretty positive this is an error, if someone could please edit the page to reflect the correct equation (I would do it but I have no idea how to edit these tables). Also note that this equation must be changed on the Delisle wikipedia page.--Corilof (talk) 16:19, 10 July 2008 (UTC)

Leyden scale

Details are sketchy.

Introduced circa 1894? Leiden, Leide, Leyde or Leyden? Symbol °L?

The scale is supposed to be the Kelvin scale shifted so the boiling points of hydrogen and oxygen are zero and 70 respectively. For oxygen, the 1 atm boiling point is in the 90.15 to 90.18 K range. For hydrogen, it depends on the variety; it is 20.390 K for "normal" hydrogen [75% orthohydrogen, 25% parahydrogen] and 20.268 K for pure parahydrogen. Assuming that absolute zero is -20.15 °L is close enough and has the virtue of giving a round shift to the Kelvin and Celsius scales.

Urhixidur 22:47, 2004 Aug 16 (UTC)

Brackets

The new by Crissov invented brackets arround [°F] look crazy. What does that mean?

Smoky 10:50, 2005 May 11 (UTC)

I didn't invent them. It's not uncommon to enclose a unit symbol in square brackets for any value given in this unit, not the unit itself. Elsewhere the convention is to use a letter for the kind of the value (e.g. F for force, W for energy or T for temperature) and make the unit/scale an index of that, often by subscripts or round brackets. In HTML there is also an element type for variables, 'var', but in most circumstances it's just italic. So what shall we use in your opinion?

Kelvin

Celsius	T°C = TK − 273.15	TK = T°C + 273.15
Celsius	TC = TK − 273.15	TK = TC + 273.15
Celsius	TCelsius = TKelvin − 273.15	TKelvin = TCelsius + 273.15
Celsius	T(°C) = T(K) − 273.15	T(K) = T(°C) + 273.15
Celsius	[°C] = [K] − 273.15	[K] = [°C] + 273.15
Celsius	°C = K − 273.15	K = °C + 273.15

Maybe this is also a matter for the MoS.

I always forget when to use lowercase Greek theta (ϑ) or uppercase Latin tee (T) for temperature values. Christoph Päper 16:48, 11 May 2005 (UTC)

The first in your table is the best way I think. However, I prefer to use italics because it is a variable.

T_°C = T_K – 273.15

T_K = T_°C + 273.15

What do you think? Yves Revi 21:06, 28 October 2006 (UTC)

Plank

Let's add the Planck unit of temperature. Jimp 17Oct05

There are several Planck units and the only one related to temperature seems to be a constant. Which unit do you mean? --ZeroOne 09:40, 17 October 2005 (UTC)

I think Jimp means to add each scale's equivalent to the Planck constant. Hans404 03:38, 9 January 2007 (UTC)

$T_{P}={\frac {m_{P}c^{2}}{k}}={\sqrt {\frac {\hbar c^{5}}{Gk^{2}}}}$ as a unit. Jɪmp 08:46, 16 January 2008 (UTC)

However, I'm not so for it now ... in fact, I wonder whether there's much point to this page at all since Conversion of units covers the main four and on the article pages for each of these there's an info box with formulae and a nav. box with links to the articles on the other scales some of which have such infoboxes and others could easily have them added (I think I'll be doing this). Jɪmp 01:44, 24 January 2008 (UTC)

Brackets again

the use of the brackets is against the standard defined in ISO 31 - it's not wrong, but in Wikipedia we should not use them this way. The right way to use the brackets is:

[T] = °C

to say this: the unit of the T (Temperature) is °C (degrees Celsius) (well it should better say Kelvin, but °C shows it better here). It would be great, if someone could add a good explanation to ISO 31-0 (I just added a short sentence there). Greetings -- 217.84.150.117 01:14, 28 July 2007 (UTC)

Wiki conversion templates

There's a handy template to display the same temperate in two units, e.g. {{convert|18|°C|°F|1}} yields 18 °C (64.4 °F). Should be mentioned somehow in the articles to teach editors about their existence. Also, there are tables which have been subject to subtle changes, which could be avoided by using the template. -- Matthead ^discuß!     O       01:03, 30 September 2007 (UTC)

It'll do three, even four, (e.g. {{convert|18|C|K F R}} yields 18 °C (291 K; 64 °F; 524 °R)) but the article space is not the place to talk about templates. Jɪmp 14:34, 24 January 2008 (UTC)

Incorrect conversion formulas

The conversion formulas on this page are incorrect, as are ALL the temperature conversions throughout various pages, for Réaumur and Rømer. The "273.13" in each of these forumlas should actually be "273.15" since this is the correct Kelvin value for 0˚C. As it stands, a conversion from Celsius -> Kelvin -> Réaumur gives an incorrect conversion from 0˚C to 0.016˚Re. Similar inaccuracies occur with Rømer conversions. I would change them all myself, but I'm not sure where to. Sbrocket (talk) 04:36, 11 March 2008 (UTC)

I noticed that. For example, this is wrong

Celsius [℃] = [K] − 273.15 [K] = [℃] + 273.15

Because Celsius clearly is not Kelvin minus 273.15 degrees. That would mean the Celsius scale is below absolute zero? (86.2.105.34 (talk) 16:19, 15 March 2008 (UTC)):

No, 0˚C = 273.15K. That is the correct conversion for Kelvin to and from Celsius. Absolute zero on an absolute temperature scale such as Kelvin or Rankine is defined as 0 degrees on that scale. Absolute zero in Celsius is -273.15˚C, since this is 0K. My comment above still stands, however - the conversion formulas are incorrect since "273.13" is used rather than "273.15". Sbrocket (talk) 17:08, 26 March 2008 (UTC)

The conversion from Kelvin to Fahrenheit is incorrect. The correct conversion is:

[°F] = ([K] * 9/5) - 241.15

and therefore from Fahrenheit to Kelvin:

[K] = ([°F] + 241.15) * 5/9  —Preceding unsigned comment added by Avens19 (talk • contribs) 16:15, 9 July 2010 (UTC) 

Your assumption that "[°F] = ([K] * 9/5) - 241.15" is wrong. Consider the freezing point of water: 0 °C = 273.15 K = 32 °F. But using your formula to derive [°F] from [K], (273.15 × 9/5) − 241.15 = 491.67 − 241.15 = 250.52 which does not equal the expected value of 32. It follows that your formula to derive [K] from [°F] is also wrong. On the other hand, using the formula in the article, [°F] = [K] × 9/5 − 459.67 = 273.15 × 9/5 - 459.67 = 491.67 - 459.67 = 32.00, as expected. — Richardguk (talk) 00:22, 10 July 2010 (UTC)

Image to table

We should remake the table image as a proper table. I'll lay the basis here. Please continue to fill it out. (Checking for errors is also good.) —Bromskloss (talk) 09:52, 13 May 2008 (UTC)

Silly me. A table like this should of course be computer generated. I've done that now with this piece of C code:

#include <stdlib.h>
#include <stdio.h>

int main(){
  double celsius, fahrenheit, kelvin, rankine, delisle, newton, reaumur, romer;

  printf("{| class=\"wikitable\" style=\"text-align:center\"\n! Celsius !! Fahrenheit !! Kelvin !! Rankine !! Delisle !! Newton !! Réaumur !! Rømer\n");

  for(celsius = 300; celsius >= -260; celsius -= 10){
    fahrenheit = celsius * 9/5 + 32;
    kelvin = celsius + 273.15;
    rankine = kelvin * 9/5;
    delisle = (100 - celsius) * 3/2;
    newton = celsius * 33/100;
    reaumur = celsius * 4/5;
    romer = celsius * 21/40 + 7.5;
    printf("|-\n| %.0f || %.0f || %.2f || %.2f || %.0f || %.1f || %.0f || %.2f \n", celsius, fahrenheit, kelvin, rankine, delisle, newton, reaumur, romer);
  }

  printf("|-\n| -273.15 || -459.67 || 0 || 0 || 559.725 || -90.1395 || -218.52 || -135.90375\n|}\n");
  exit(0);
}

—Bromskloss (talk) 12:31, 2 June 2008 (UTC)

Merge

Merged Comparison of temperature scales into this article, since no-one seemed to care either way.

Removing the graph

I'm removing the graph as it is either incorrect or at least easily misinterpreted. For example, the Celsius line would seem to indicate that ice melts at about -100C, and the Fahrenheit line seems to indicate that average human body temperature is about 40F, both of which are clearly incorrect. BW95 (talk) 20:26, 26 August 2009 (UTC)

Never mind. I see the diagonal linking lines now and have undone the deletion. Still, their lightness in color makes them hard to see and, again, contributes to easy misinterpretation of the chart (as I've just done). BW95 (talk) 20:41, 26 August 2009 (UTC)

Possible additional external link

I'd like to propose an addition to the external link section. Right now there is a single link to a converter handling Fahrenheit, Celsius, Kelvin and Rankine. The following converter handles (as of this writing) those four scales plus 38 additional ones and furnishes the conversion formula and intersection points (if any) for whichever pair you choose:

http://www.curiousnotions.com/temperature-conversion

Many of those scales are pretty ancient and informally defined, but the page acknowledges this. Kukisvoomchor (talk) 00:26, 25 June 2010 (UTC)

Comparison of temperature scales graph png -> svg

The new chart doesn't seem to be working for me. The text at the bottom overlaps. My regular browser is Chrome, but the problem occurs in IE9 and Firefox as well. My Wikipedia appearance preference is default, and thus Vector theme. Hope this helps. Zyxwv99 (talk) 13:33, 28 April 2012 (UTC)

Dead link

References link 1 (for the lowest temperature ever recorded on Earth) is dead. — Preceding unsigned comment added by 2.80.202.159 (talk) 18:29, 2 May 2012 (UTC)

Celsius

The conversion from celsius to Rankine is wrong. It currently says: [°R] = ([°C] + 273.15) × 9⁄5 It should be: [°R] = ([°C] + 491.67) × 9⁄5 — Preceding unsigned comment added by 86.88.184.43 (talk) 14:49, 7 May 2013 (UTC)

Intersections chart/table

It would be nice to have a chart/table showing intersections, such as where Celsius (°C) and Fahrenheit (°F) meet at -40.00°. -- Brangifer (talk) 19:12, 11 October 2013 (UTC)

Add indications of Current vs Archaic -- if possible

I come to Wikipedia for clear, concise and accurate information. Today's search for "standard temperatures" has wasted my entire afternoon (I am an engineer). While this topic should include "conversions" between most (or all) units or scales of temperature -- there should be some indication (somewhere) of Current or Common vs. Archaic, Abandoned or Obscure scales. Please improve. Thanks for your work HalFonts (talk) 22:29, 4 March 2015 (UTC)

Your complaint and its remedy isn't clearly expressed. I have though added more obvious links to the sections on each scale. Andy Dingley (talk) 23:01, 4 March 2015 (UTC)

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Boiling point in the table comparing scales

The boiling point does appear in the graphic but not in the table above 87.218.84.22 (talk) 12:30, 17 December 2023 (UTC)

It's the third line from the bottom in Conversion of scales of temperature#Comparison of temperature scales. NebY (talk) 13:23, 17 December 2023 (UTC)