What is thermodynamics?This is a section of physics that deals with the study of the properties of macroscopic systems. At the same time, the methods of energy conversion and methods of its transmission also fall under the study. Thermodynamics is a branch of physics that studies the processes taking place in systems and their states. About what else falls into the list of things studied by her, we'll talk today.
Definition
In the picture below you can see an example of a thermogram obtained from a jar with hot water.
Thermodynamics is a science that relies ongeneralized facts obtained empirically. The processes occurring in thermodynamic systems are described by using macroscopic quantities. Their list includes such parameters as concentration, pressure, temperature and the like. It is clear that they can not be applied to individual molecules, but are reduced to describing the system in its general form (in contrast to those used in electrodynamics, for example).
Thermodynamics is a branch of physics that alsohas its own laws. They, like the rest, are of a general nature. The concrete details of the structure of a given substance will not have a significant effect on the nature of the laws. That is why it is said that this section of physics is one of the most applicable (or, to be more correctly, successfully applicable) in science and technology.
Application
Enumerate examples can be very long.For example, many solutions based on thermodynamic laws can be found in the field of thermal engineering or electric power engineering. What about the description and understanding of chemical reactions, phase transitions, transport phenomena. In a way, thermodynamics "cooperates" with quantum dynamics. The sphere of their contact is a description of the phenomenon of black holes.
Laws
The picture above demonstrates the essence of one of the thermodynamic processes - convection. The warm layers of matter rise to the top, the cold layers - go down.
The alternative name of laws, which, by the way,it is used not as an example more often, it is the beginning of thermodynamics. To date, they know three (plus one "zero", or "general"). But before talking about what each of the laws implies, we will try to answer the question of what the beginnings of thermodynamics are.
They are a collection of definitepostulates, which form the basis for understanding the processes occurring in macrosystems. The positions of the beginning of thermodynamics were established empirically as the series of experiments and scientific research were carried out. Thus, there are certain proofs that allow us to take the postulates into service without any doubt about their accuracy.
Some people are wondering whyThermodynamics needs these same laws. Well, we can say that the need for their use is due to the fact that in this section of physics the macroscopic parameters are described in a general way, without any hint of considering their microscopic nature or features of the same plan. This is not the sphere of thermodynamics, but of statistical physics, to be more specific. Another important thing is the fact that the onset of thermodynamics does not depend on each other. That is, one of the second can not be deduced.
Application
The application of thermodynamics, as was said earlier,goes in many directions. By the way, one of its principles is taken as a basis, which is otherwise interpreted in the form of the law of conservation of energy. Thermodynamic solutions and postulates are successfully introduced into such branches as energy industry, biomedicine, chemistry. In biological energy, the law of conservation of energy and the law of probability and direction of the thermodynamic process are universally used. Along with this, three most common concepts are used there, on which all work and its description are based. This is a thermodynamic system, the process and the phase of the process.
Processes
The processes in thermodynamics have different degreesdifficulties. There are seven of them. In general, the process in this case should be understood as nothing more than a change in the macroscopic state into which the system was introduced earlier. It should be understood that the difference between the conditional initial state and the final result can be negligible.
If the difference is infinitesimal, then what happenedwe can easily call the process elementary. If we discuss processes, we will have to resort to mentioning additional terms. One of them is the "working body". A working body is a system in which one thermal process takes place or several.
Conditionally the processes are subdivided into nonequilibriumand equilibrium. In the case of the latter, all the states through which the thermodynamic system has to go through are, respectively, nonequilibrium. Often, the change in state occurs in such cases at a rapid pace. But the equilibrium processes are close to quasi-static. In them, the changes are much slower.
Thermal processes occurring inthermodynamic systems can be both reversible and irreversible. In order to understand the essence, we divide in our view the sequence of actions into certain intervals. If we can do the same process in the opposite direction with the same “intermediate stations”, then it can be called reversible. Otherwise, it will not work.
