Science Degree Program in China - Thermology

1. Introduction

Thermology is a branch of physics that studies the properties and laws of matter in a state of heat. It originates from the exploration of the phenomenon of heat and cold. The phenomenon of cold and hot phenomena is one of the natural phenomena in the natural world, which is one of the earliest observations and understanding in the natural world.

2. Thermodynamics

Thermodynamics is mainly from the point of view of energy conversion to study the thermal properties of the material, it reveals the energy from one form to another form of compliance to the macro law.

Thermodynamics is the thermal theory obtaining from the summary of the macroscopic phenomena of the material, which does not relate to the microscopic structure of the material and the interaction of the microscopic particles. So it is a phenomenological macro theory, with a high degree of reliability and universality.

The three laws of thermodynamics is the basic theory of thermodynamics. The first law of thermodynamics reflects the relationship between energy conservation and transformation, which introduces the state function of the system. The first law of thermodynamics can be expressed as: the first kind is not possible.

One of the important phenomena in thermology is to tend to the equilibrium state, which is an irreversible process. For example, the temperature of different two objects in contact, and finally reach the equilibrium state, the two objects will have the same temperature. But its inverse process, that has the same temperature of two objects, will not go back to the temperature of the different state.

3. Zero Law of Thermodynamics

In the case of no external influence, as long as A and B are in a thermal balance at the same time with C, even if A and B have no thermal contact, they are still in a state of thermal equilibrium.

Physical meaning: there is a common characteristic between the objects of heat balance -- their temperature is the same; not only the concept of temperature, but also the method of judging whether the temperature is the same.

4. First Law of Thermodynamics

Heat can be transferred from one object to another, and can be converted to mechanical energy or other energy, but in the conversion process, the total value of the energy remains constant.

5. Second Law of Thermodynamics

1) It is impossible to make the heat from the object with low temperature to the object with high temperature without other changes.

2) The direction of heat conduction

The process of heat conduction is directional, and this process can be carried out spontaneously, but not in the opposite direction.

3) The second kind of perpetual motion machine

Only a single heat source, the heat that it absorbs from the single heat source can all be used to act, without causing other changes, people call this kind of imaged heat engine the second kind of perpetual motion machine. The second kind of perpetual motion machine cannot be made, shows that the transformation process of mechanical energy and internal energy have direction.

4) Energy dissipation

Energy dissipation is a reflection of the nature of the macro process from the perspective of energy conversion.

6. Research Objects

Thermal expansion and contraction of the material, heat conduction, diffusion, conductor resistance change with temperature and material can proceed three state changes of solid, liquid, gas; the phenomenon that the physical properties change with the temperature is known as thermal phenomena.

The heat phenomenon is caused by a large number of molecules in the interior of the material. When the laws of thermal phenomena are discussed and studied, the whole macroscopic mechanical motion of the object is no longer in the category of discussion, and the people will look at the large amount of molecular motion in the interior of the material. Different from the concept of mechanical movement, people will be a large number of irregular movements of the molecules formed by the macro material to the thermal phenomenon as the main symbol of the movement form called thermal motion. A thermal phenomenon is the macroscopic manifestation of the thermal motion, and the thermal motion is the microscopic nature of the thermal phenomenon.