The first law of thermodynamics for the average person.

All human activity is based on energy consumption. Without energy it is difficult to imagine the activity of the organism, the functioning of all goods for people. It is important both within a person and for his external existence. Different industries cannot work on their own, because they require energy. Transportation of goods, space heating, synthesis of new substances in the cells of the body - all this is due to the ability to produce work.

The place of energy in thermodynamics

first law of thermodynamics definition

In order to determine the place of energy in this branch of science, one should find out what exactly the term "thermodynamics" implies. This is a field of physics in which energy conversion processes are studied in depth. Everyone knows the fact that energy is represented in several forms: it can be chemical, electrical, thermal, mechanical and light. This branch of science even has its own laws and principles, for example, the first law of thermodynamics, as well as some others.On this basis, it can be said that this area of ​​knowledge would not exist if the properties of the above-described physical quantity were not known.

How is the transformation of energy?

first law of thermodynamics

Many people do not understand the fact of energy transfer from one state to another. But we in everyday life so often use the transient energy that we no longer give an account of where it comes from. So, for example, when we get into a car every day, we do not think that at the moment of driving the chemical energy goes into electrical energy. In an electric motor, the initial electrical energy is converted into mechanical energy, and in a steam turbine, heat is converted into mechanical physical quantity. With all this, there are certain quantitative ratios of different forms of energy. But during the transformation processes occur with some quantitative losses: the consumption of useful energy is always higher than its production. This phenomenon is easily explained: transformation is not complete without friction; during it, some of the energy becomes heat and is dissipated in space. It turns out that this part can no longer be used as a useful quantity.Thus, any conversion is not lossless.

The first law of thermodynamics

Studying the process of energy conversion, scientists discovered two fundamental laws. This article will be devoted to the first of them. This law of thermodynamics says: for any change - chemical or physical - the amount of energy remains constant. In another way, it is also called the law of conservation of energy. From this definition it follows that energy does not suddenly appear and simply does not disappear. If in the process of any activity it goes into different forms, from one to another, then its total number does not change. In other words, energy is not created or destroyed, which reflects the first law of thermodynamics. Definition in different sources may vary, but the essence remains the same.

first law of thermodynamics

The history of the discovery of this law

Begins its law since the middle of the XIX century. The German physician Mayer, watching how the color of human blood changes in the tropics, thought about the relationship between such physical concepts as heat and energy. In turn, the famous scientist Joule drew attention to the development of Mayer, something added on his part.All the data on this law was united by another German doctor, Helmholtz, when he studied the physical fundamentals of the organs of perception - human hearing and vision. It was he who formulated the law in such a way that the whole world knows it today.

Types of energy exchange

The heat that occurs when one type of energy is transferred to another affects the change in the internal energy of an object. When it changes, there is opposition to the work of external forces that affect this object. The internal energy can be kinetic (this is the movement of atoms of an object), potential (it is stored in chemical bonds between atoms), the gravitational energy of the entire system (that is, the influence of gravitational forces on the object, which also appear inside). Based on these species, scientists have identified certain types of energy exchange.

  • The first of them is commonly understood as pre-insulated systems - there is no exchange of energy and other elements of a particular system.
  • The second type is closed systems, characterized by the lack of exchange of system elements, but to an insignificant degree energy is exchanged.
  • Open systems (the third type of exchange) are characterized by the exchange and energy, and their elements.

The concept of internal energy in thermodynamics

first law of thermodynamics

The internal energy of an object or system in thermodynamics plays an almost key role. In fact, this is a complex combination of several activity streams of molecules and atoms. It consists of such species as the energy of the rotational and translational motion of molecules, the energy of the motions of atoms and groups of atoms, which is inside the molecules and is emitted when these particles oscillate. More to the internal energy of the subject include the nuclear energy of atoms and the energy of interaction between molecules. Uextdepends on the initial state of the object and the final indicators of its state. This energy is continuous, as its first law of thermodynamics. It can be easily calculated by the following formula: the heat added to the system, minus the work done by this system. Here we are not talking about the nature of the process of changing internal energy, not even about the final state of equilibrium, as this determines the second law of thermodynamics.

The relationship of heat and internal energy

These concepts are very closely related. It is assumed that heat is part of the internal energy of the system. We will understand what is the heat.The subject itself does not have such in the usual sense of the word. It can be said that heat is the energy that passes from an object having a high temperature to an object with a temperature lower than that of the first.

first law of thermodynamics

In other words, it is a part of the internal energy of the object, which is transferred from it, since it has temperature indicators higher. Such a transfer in physics and chemistry is called heating.

The first law of thermodynamics, chemistry

This law is of fundamental importance not only for physical experiments, the study of phenomena and the discovery of new processes, but also for another science - chemistry - and its related industries. When studying the existence and transfer of energy into different forms from the perspective of chemical reactions of the body or object, a horizon of interesting research and patterns in the bioenergy plane opens.

first law of thermodynamics chemistry

Many may feel that the first law of thermodynamics is distant from the life of an ordinary person, that molecules and atoms are only subject to understanding by a small number of dedicated people. But this is far from the case. The basis of life of every living organism is metabolism, which cannot occur without the transformation of energy.Therefore, chemical processes of energy conversion in the human body are of particular interest not only for physicists, but also for dietitians and sports instructors. After all, knowing all the features of this process, you can successfully help people get rid of extra pounds, as well as look after themselves with the help of a correctly composed menu consisting of healthy food.

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