-THERMODYNAMICS-
In the field of thermodynamics, Ludwig Boltzmann has been able to explain various phenomena in relation to the exchange of energies of gas systems based on the kinetic energies of the molecules. Such a theory was also a unification of works previously done by Gottfried Leibniz, Sadit Carnot and Rudolf Clausius. The point was to understand how the energy exchanges took place and what happened in this process.
Sadit Carnot said that Heat has a sense, a flow and this flow was from the higher to the lower temperature system, such concepts are those that were used in the creation of thermal machines in the 19th century. Rudolf Clausius said that "every thermodynamic system has its energy dissipated over time, a concept he called Entropy, in other words, Entropy always increases over time.
But what is Entropy? A simple way to understand what entropy is ...
Imagine a mug that is filled with hot coffee, and you leave it on the table and wait a few hours, when you touch the mug again, you realize that it was not as hot as before, that is, the heat dissipated into the room. Similarly, we say that the mug was in thermal equilibrium with the environment. Entropy, we might say, is a quantity that measures the disorder of the system, or its disorganization, as in the example cited ... the heat was concentrated at a certain point (mug) then spread to the environment.
With these two concepts formulated by Rudolf Clausius and Sadit Carnot, Boltzmann had the following interpretation of the second law of thermodynamics (entropy). Boltzmann said that to better understand entropy we need to better understand the microscopic world, how gas molecules behave at low and high temperatures.
Seeing this Boltzmann studied hard and concluded that in order to understand the physics of the molecules of a gas, one would have to expect to analyze molecule by molecule, something inconceivable! Impossible to do such a study, then Boltzmann realized that in order to understand the physics behind the molecules of a gas he would have to abandon certainty (determinism) and adopt probability and statistics (stochastic) in order to fully understand the motions of gas. molecules of a gas. The equation that describes this discovery today is written on his tombstone in his honor.
S-entropy; k- Boltzmann constant; W- probability
Video edited and subtitled to Portuguese, taken from a BBC documentary "Order and Disorder, The History of Energy"