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The rubber band experiment can be modeled as a thermodynamic cycle as shown in the diagram. The stretching of the rubber band is an isobaric expansion (A → B) that increases the energy but reduces the entropy (this is a property of a rubber bands due to rubber elasticity). Holding the rubber band in tension at ambient temperature is an ...
Rubber as an Engineering Material (book), by Khairi Nagdi: "The Joule effect is a phenomenon of practical importance that must be considered by machine designers. The simplest way of demonstrating this effect is to suspend a weight on a rubber band sufficient to elongate it at least 50%.
A rubber band is a single molecule, as is a latex glove. ... The concept of entropy comes to us from the area of mathematical physics called statistical mechanics ...
Note however, the work done by a stretched rubber band is not an example of elastic energy. [citation needed] It is an example of entropic elasticity.) The elastic potential energy equation is used in calculations of positions of mechanical equilibrium.
He is known for being the first to apply Boltzmann's entropy formula: [2] = to the modeling of rubber molecules, i.e. the "rubber band entropy model", molecules which he imagined as chains of N independently oriented links of length b with an end-to-end distance of r. [3]
The relationship between entropy, order, and disorder in the Boltzmann equation is so clear among physicists that according to the views of thermodynamic ecologists Sven Jorgensen and Yuri Svirezhev, "it is obvious that entropy is a measure of order or, most likely, disorder in the system."
When stretching the rubber band, you also align the structure to be more ordered. Therefore, when releasing the rubber band, it will spontaneously seek higher entropy state hence goes back to its initial state. This is what we called entropy-driven elasticity shape recovery. Region IV: The behavior in the rubbery flow region is highly time ...
A further analogy consists in the already mentioned similarity to polymer physics, where, analogously to Wilson loops, so-called "entangled nets" appear, which are important for the formation of the entropy-elasticity (force proportional to the length) of a rubber band.