Talk:Mechanical equivalent of heat

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Modern connections needed

At present this article is only a historical retrospective, and a gloss at that. A modern presentation of our understanding of the connection between the kinetic macro and thermo micro scale is missing as is a more thorough mathematical treatment of the topic. 76.182.76.243 (talk) 14:17, 3 July 2020 (UTC)[reply]

Priority

The sentance which starts with "However, in 1848, Mayer had first had sight of Joule's papers..." is very confusing. Both because of the double "had" and also because it isn't clear (to me) what "first sight" is supposed to imply.

Rumford

I have to point out that the priority should be credit to Count Rumford (Benjamin Thompson) for his work "An Experimental Enquiry Concerning the Source of the Heat which is Excited by Friction" where he suggested that heat is a form of motion. This work was published in 1798 more them 40 years before Joule and Mayer's works.

Although Mayer and Joule are to be credit as the first ones to find the proportional relation between the Unity of mechanical work (now called Joule) and the unity of heat (calorie), they are certain not the first ones to propose the concept equivalence.

Picture of Apparatus

Someone needs to provide a simplified diagram of the calorimeter which is used to find the electrical equivalent of heat. An EQUATION for the electrical equivent is NOT the same thing as a --- however simplified ---picture of the corresponding experiment.

This is now the second time that I have tried to find a picture and run instead into equations. If Wikipedia is to serve the general population, PICTURES ARE ESSENTIAL Whillier (talk) 02:41, 20 November 2009 (UTC)Whillier[reply]

Definition of Heat

The definition of heat is a transfer of energy due to a temperature difference between two systems. It is a process, not a state. This article uses the term incorrectly in several places. Historically, there may not have been a distinction between heat (process) and thermal energy (state), but now there is. This article fails to make this distinction. —Preceding unsigned comment added by 199.101.9.8 (talk) 18:15, 23 February 2010 (UTC)[reply]

History - Mayer

One might mention that already in 1842 Mayer provided a value for conversion cal/J. In

Robert Julius von Mayer: Bemerkungen über die Kräfte der unbelebten Natur. In: Annalen der Chemie und Pharmacie. XLII, No 1, 1842, page 240 [1] page 240

he writes: "...das dem Herabsinken eines Gewichtstheiles von einer Höhe circa 365 m die Erwärmung eines gleichen Gewichttheiles Wasser von 0° auf 1° entspreche." i.e. a mass descending by 365 meters corresponds to heating the same mass of water from 0 to 1 degrees Celsius, which is in modern units (with mass = 1 kg)

1 kcal₀ ≙ 365 kp·m = 3,58 kJ

This is deviates by 15 % from to today's value 4,2 J/cal

Wassermaus (talk) 09:49, 12 February 2025 (UTC)[reply]