What is thermodynamics? This is a branch of physics that deals with the study of the properties of macroscopic systems. At the same time, methods of converting energy and methods of its transfer also fall under the study. Thermodynamics is a branch of physics that studies the processes occurring in systems and their states. We'll talk about what else is on the list of things she studies.
Definition
In the picture below you can see an example of a thermogram obtained when studying a jug of hot water.
Thermodynamics is a science that relies on generalized facts obtained empirically. The processes occurring in thermodynamic systems are described using macroscopic quantities. Their list includes parameters such as concentration, pressure, temperature, and the like. It is clear that they are not applicable to individual molecules, but are reduced to a description of the system in its general form (in contrast to those quantities that are used in electrodynamics, for example).
Thermodynamics is a branch of physics that also has its own laws. They, like the rest, are of a general nature. Specific details of the structure of aany other substance we have chosen will not have a significant effect on the nature of the laws. That is why they say that this branch of physics is one of the most applicable (or rather, successfully applied) in science and technology.
Application
The list of examples can be very long. For example, many solutions based on thermodynamic laws can be found in the field of thermal engineering or the electric power industry. Needless to say about the description and understanding of chemical reactions, phase transitions, transfer 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. Warm layers of matter rise up, cold layers fall down.
An alternative name for the laws, which, by the way, is used more often than not, is the beginning of thermodynamics. To date, there are three of them (plus one “zero”, or “general”). But before talking about what each of the laws implies, let's try to answer the question of what the principles of thermodynamics are.
They are a set of certain postulates that form the basis for understanding the processes occurring in macrosystems. The provisions of the principles of thermodynamics were established empirically as a whole series of experiments and scientific research was carried out. Thus, there is some evidenceallowing us to adopt the postulates without a single doubt about their accuracy.
Some people wonder why thermodynamics needs these very laws. Well, we can say that the need to use them is due to the fact that in this section of physics, macroscopic parameters are described in a general way, without any hint of consideration of their microscopic nature or features of the same plan. This is not the field of thermodynamics, but of statistical physics, to be more specific. Another important thing is the fact that the principles of thermodynamics are independent of each other. That is, one of the second will not work.
Application
The application of thermodynamics, as mentioned earlier, goes in many directions. By the way, one of its principles is taken as a basis, which is interpreted differently in the form of the law of conservation of energy. Thermodynamic solutions and postulates are being successfully implemented in such industries as the energy industry, biomedicine, and chemistry. Here in biological energy, the law of conservation of energy and the law of probability and direction of the thermodynamic process are widely used. Along with this, the three most common concepts are used there, on which the entire work and its description are based. This is a thermodynamic system, process and process phase.
Processes
Processes in thermodynamics have varying degrees of complexity. 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, inwhich the system was given earlier. It should be understood that the difference between the conditional initial state and the final result can be negligible.
If the difference is infinitely small, then we can call the process that has taken place elementary. If we discuss processes, we will have to resort to mentioning additional terms. One of them is the “working body”. A working fluid is a system in which one or several thermal processes take place.
Processes are conventionally divided into non-equilibrium and equilibrium. In the case of the latter, all the states through which the thermodynamic system has to pass are, respectively, nonequilibrium. Often, the change in states occurs in such cases at a rapid pace. But equilibrium processes are close to quasi-static ones. In them, changes are an order of magnitude slower.
Thermal processes occurring in thermodynamic systems can be both reversible and irreversible. In order to understand the essence, let us divide in our representation the sequence of actions into certain intervals. If we can do the same process in reverse with the same "way stations", then it can be called reversible. Otherwise, it will not work.
