Graphical Thermodynamics in the Works of J. Willard Gibbs
Gibbs first two papers on thermodynamics were entitled “Graphical Methods in the Thermodynamics of Fluids” [1] and “A Method of Geometrical Representation of the Thermodynamic Properties of Substances by Means of Surfaces” [2]. In these papers he utilized the combined First and Second Laws of Thermodynamics to show that the equilibrium states of a simple one component system are represented by a surface in the Internal Energy- Entropy and Volume (U-S-V) three-dimensional space. From this U-S-T plot all the thermodynamic variables of a simple system (U, S, V, T and P) at a given state can be determined.
I will present highlights of these two papers and show how they can be used in clarifying various aspects of thermodynamics in a geometric fashion. Of particular interest is the Temperature- Entropy (T-S) plot, and the Internal Energy-Entropy (U-S) plot (Figure 3 of paper [2] of Gibbs). In addition, the U-S plot can be used to develop a geometric visualization of the Third Law of thermodynamics (Gibbs was very close to getting it!). Other thermodynamic plots will be presented to demonstrate the graphical connectedness of the thermodynamics as developed by Gibbs. If time permits other interesting thermodynamic topics will be discussed.
[1] Transactions of the Connecticut Academy, II 309-342, April-May 1873.
[2] Transactions of the Connecticut Academy, II 382- 404, December 1873.