Definition of Thermal Equilibrium

The Balance thermal It's that one state in which the temperatures of two bodies are equal, which, in their initial conditions, presented different temperatures. Once the temperatures are equal, the heat flow is suspended, reaching both bodies at the aforementioned term equilibrium.

State in which the temperatures of two bodies are equal

Thermal equilibrium is a concept that is part of thethermodynamics, the branch of physics concerned with describing equilibrium states at a macroscopic level.

Description of the process and the relevance of thermodynamics in its study

The bodies do not have heat in a natural and innate way in them but Energy, being that heat is the energy that is transferred from one body to another, from the largest to the smallest temperature.
This energy will pass between two materials that are joined by a diathermic surface until the other body balances the temperature. This question is what assures us of the change in vital development.

When two systems are in direct mechanical contact, or failing that, separated by a surface that facilitates heat transfer,

diathermic surface, it will be said that both are in thermal contact. Meanwhile, after a while, although the two systems that are in thermal contact are arranged in such a way that they cannot mix or although are placed inside a space in which it is impossible for them to exchange heat with the outside, they will inevitably reach the state of equilibrium thermal.

At a macroscopic level, the situation of two systems in thermal contact can be interpreted because the particles on the interface surface of the two systems are capable of interacting with each other; what will be seen is that the particles of the system that has a higher temperature will transfer part of their energy to the particles of the other system that has a lower temperature. The aforementioned interaction will make the particles of both systems achieve the same energy and therefore the same temperature.

When a body is hot it is easy to detect through our senses, especially touch, that we touch it and of course at the moment we feel its heat in our hands. In any case, on some occasions it is complex to explain the reason for this, that is, to determine the type of process that is maintained inside that body so that it occurs in such a way.

The reason is found in the movement, being that heat is the manifestation of the Kinetic energy.
When a body takes heat, the particles that make it up will begin to move with a velocity greater and thus the hotter the body is, its particles will move faster.
Of course, this process cannot be observed with the naked eye, that is, with our eyes, but it is possible to do it through the use of an element such as microscope, which precisely allows us to visualize the small particles.

When the movement of two systems of particles is observed, we must bear in mind that if it is identical in both, that system is already in equilibrium. While on the contrary, if the interacting systems have particles that move at different speeds, those that are They move less fast will tend to accelerate and those that move at a higher speed will become slower, that is, they will tend to Balance.

In order to know the temperature of a body or substance, the device of the thermometer. When the thermometer comes into thermal contact with the body in question, both will reach thermal equilibrium and then when they meet at the same temperature, we will know that the temperature indicated by the thermometer in its index will be the body temperature that occupies.

This process and the intervention of the aforementioned thermodynamics with its explanations and postulates in this regard are relevant to understand how various work procedures natural as well as to understand some forms of energy loss suffered by some machines.
Thermodynamics owes its development largely to the study that was carried out to discover alternatives that would lead to the greater efficiency of the machines, and that had its beginning in the Revolution Industrial.

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