The second law of thermodynamics

Even in ancient times, the regularity of heat distribution was noticed: heat can spontaneously transfer from a heated body with a higher temperature to a less heated one. The second law of thermodynamics, explaining this process, was discovered experimentally. For the first time its essence was expounded in 1824 by S. Carnot, a French engineer who determined how and under what conditions the fire went into useful work in the cars of that time. In the middle of the 19th century, on the basis of this, the German scientist Rudolf Clausius formulated a rule that is now known as the second law of thermodynamics. Its essence is that heat never passes to a warmer body from a less heated spontaneously, that is, the transition of heat to a body with a higher temperature must be compensated by an external energy supply. Examples include refrigeration. Later, W. Thomson and some other scientists clarified the formulation of this law.

This principle is understood even more widely than in the treatment of Rudolph Clausius. Take, for example, the transformation of work into heat. It can be produced by the force of friction. At the same time, work is transferred to the heat completely, without any additional effort and compensation. The reverse transformation is not possible by itself. The transfer of heat to work is already an artificial process, that is, requiring special, artificially organized conditions.

In general, the second law of thermodynamics formulates the principles of the course and direction of natural processes. Proceeding from it, it is possible to explain the functioning of a number of devices. So, thermal engines work at the expense of a difference of temperatures thanks to which heat passes from a heated part to a cold one - from a heat sink to a heat sink. And in this case, the efficiency of the device can not be 100%. That is, not all heat is converted into work, but only a part of it. This can partially explain the fact that it is impossible in principle to create a perpetual motion machine (of the second kind). In other words, a device that would completely and without any compensation turn heat into work will never be invented. Proceeding from all the above, the scientists R. Clausius and W. Thompson defined the formulation of the second law of thermodynamics. First, spontaneous heat can not pass from warmer to warmer bodies; Secondly, not all heat, directed from the heat sink to the heat sink, goes into useful work, but only a part of it. There are also several similar formulations, which, in general, are a reflection of the above. Passing from the heat transfer device to the heat receiver, the energy does not disappear anywhere, therefore the law of conservation of the total amount of energy does not contradict the second law of thermodynamics. Its definition was developed by several scientists and consists of several main theses, which are considered in this article.

The processes that are associated with the transformation of energy can spontaneously proceed only if the energy from the concentrated form has passed into the scattered one. One of the most important abilities, peculiar to people as well as the biosphere, ecosystems is the ability to low entropy. The latter term refers to the ratio of the amount of heat to the temperature value, is a kind of measure of chaos and is associated with the loss of the ability of any system to perform certain work; When the volume of the system or its energy changes, the entropy decreases.

In 1865 R. Clausius finally formulated the second law of thermodynamics. Entropy, by its definition, increases when spontaneous processes occur in any closed nonequilibrium system.

The second law of thermodynamics subordinates the so-called principle of ecological pyramids; In addition, he is the source of the Lindemann Law, which explains the principles of energy circulation in the ecosystem. It indicates the unidirectionality (irreversibility) of spontaneous processes occurring in nature. In accordance with this, energy is converted into heat, and heat is transferred to the colder body from the heated one, which leads to equalization of temperatures at a low level, the consequence of which is the cessation of all forms of motion of matter, or so-called. "Heat death". If we speak in clear and simple language, then the essence of the second law of thermodynamics is this: all spontaneous, natural processes result in chaos, degradation. This can be explained in this example: if the house is left for many years without the owner, it will gradually decline, collapse.