ESHS/HSS Annual Meeting

The Emergence of Energy Conservation: the Contribution of Developments in Mechanics

• In Event: Emergence and Interpretation of the Principle of Energy Conservation in the Long 19th Century

English Abstract

Historians have justly dismissed the anachronistic tendency to regard the principle of energy conservation as merely an extension of classical mechanics. Yet, consequently they often undermined the contribution of developments in mechanics and its employment in the first half of the 19th century to the emergence of the principle. Building on the studies of, inter-alia, Grattan-Guiness, Darrigol and myself, I will claim that developments within mechanics and the extension of its employment advanced the view of conservation in nature and the conceptualization of the conserved quantity. The denial of hard collisions, long considered as necessitated by the atomic hypothesis, allowed turning non-frictional mechanics itself to be conservative. The physical concept of work (and its equivalents), useful to describe loss of power, arose from discussions of such apparent interactions in machines. Within the later view of conservation, the concept of work facilitated the quantification of transformations. The principle of conservation of vis viva was employed in cases where motion was converted into a change of physical state in reversible processes, and was also associated with the impossibility of creating power out of nothing. Following the development of new subfields, its application was extended to include also optics, electrodynamics and thermodynamics, leading formally to pre-energetic conclusions about the impossibility to attain work out of nothing, at least for particular transformations. These ideas were further taken up and generalized by scientists without a similar mathematical background such as Faraday, Liebig and Joule. At least through Carnot, this tradition also influenced Helmholtz, who was well versed in its formalism.

Author

• Shaul Katzir, Tel Aviv University