Thermodynamics - the branch of physics which studies the mutual transformation of heat into movement, and vice versa.Being a fairly extensive section, this part of the Applied Physics is divided into several different divisions, which include:
- basic laws of thermodynamics.
- Phase transitions and thermodynamic processes.
- thermodynamic cycle, and others.
In fact, the laws of thermodynamics - not just the sub, but also postulates the basis of the underlying physics of the studied section.In total there are three thermodynamic start.
consider them in detail.
1. The first law of thermodynamics, or the beginning.First, let us remember that energy is constantly transferred from one species to another.Transforming, depending on the conditions of kinetic into potential energy and vice versa, the energy does not go out of the system.However, a simple example of the pendulum, which gives the acceleration, casts doubt on this theory.While in motion, the pendulum has a kinetic energy at the extremes of the amplitude - potential.Theoretically, this movement should have no end in sight, it is to be infinite.In practice, we see that the movement is gradually fading, the pendulum stops its course.This occurs due to the air resistance, which causes the friction force at movement.As a result of the energy that should have been given to the pendulum acceleration used to overcome the air barriers.As a consequence, the heat generated.According to the experience of scientists, the temperature of the suspension and the environment is enhanced by the chaotic movement of the molecules of matter of the pendulum and air.
Actually, the first law of thermodynamics is better known as law of conservation of energy. Its essence is that the energy of the system does not disappear, but only converted from one form to another and moves from one form to another.
similar observation was first described in the mid-nineteenth century.K. Moore.He pointed out that the energy can go into other states: heat, electricity, movement, magnetism, and so on. D. However, the law was formulated only in 1847, Helmholtz, and in the twentieth century.he was awarded the notorious formula E = mc2, which also included the conclusions of Einstein.
2. The second law of thermodynamics, or the beginning.Formed in 1850, scientists R. Clausius, it is the observation that the internal distribution of energy in a closed system changes randomly, so that useful energy is reduced, thereby increasing the entropy.
3. The third law of thermodynamics, or the beginning.Having in mind the idea that heat is a chaotic and random movement of molecules, we can conclude that the cooling system entails a decrease in their physical activity.Entropy is zero in the case where any random movement of molecules is completely stopped.
absolute value of the entropy of a substance can be calculated from his heat at absolute zero.W. Nernst by long and numerous studies it was found that all crystalline materials have the same heat capacity at zero and it is equal to zero.This conclusion is the third law of thermodynamics.Knowing this fact, it is possible to compare the entropy of the various materials during temperature changes.
There is also the so-called zero law of thermodynamics , s aklyuchaetsya it as follows: the heat from the heated portion of an isolated system applies to all of its elements.Thus, over time, the temperature within the one system is aligned.
laws of thermodynamics - is the basic components of the science of mechanics.Due to the findings committed at different times, modern science and society are enriched at the expense of the invention, the majority of machines.
The laws of thermodynamics are universal for all branches of mechanics.
