Introduction To Thermodynamics: Thermal Physics

Thermodynamics: Thermal physics

By:Guled Elmi

Teacher: Mr.Ali Kammar

1.1 Introduction to Thermodynamics:

Thermodynamics is the branch of physical science that deals with the relations between heat and other forms of energy (such as mechanical, electrical, or chemical energy), and, by extension, of the relationships between all forms of energy.

The first law states maintain energy: energy can be stored in the system on the internal energy or kinetic energy form, and can be exchanged with the outside world in the form of work or heat.

First law of Thermodynamics:

Increase in internal energy = Energy supplied by heating +energy supplied by doing work

Thermal energy is the energy that comes from heat. This heat is generated by the movement of tiny particles within an object. The faster these particles move, the more heat is generated. Thermal energy flows from region of higher temperature to lower temperature.

Direction of thermal energy flow:

1.3 . Equilibrium States:

When two regions are at the same temperature, no transfer of thermal energy takes place; this is called (Thermal Equilibrium). Thermal energy flows from the region of higher temperature to the region of lower temperature.

Transfer of power in the form of temperature process heat, because whenever continued heat transfer energy from one object to another, the molecules that sucks the heat in the body speed will increase, and therefore the kinetic energy of the body increases. It is known that the greater the kinetic energy of the body temperature increases.

Example: Thermal energy is transferred from lower temperature to higher temperature because of the temperature difference between them and also since the thin wall allows good heat flow. When they are at the same temperature, there is no transfer of thermal energy since they are in thermal

It makes use of a certain thermal property that varies with temperature.

4.1 Transfer of thermal energy:

Thermal energy is always transferring from a place with high temperature to a place with low temperature. So we can say that the direction of the thermal energy transferring is from warmer place to a colder one.

The main ways for transfer of thermal energy are:

• conduction

• convection

• radiation

Conduction: When we have a direct contact between at least two objects with a different temperature. The warmer objects transfer energy to the colder object and because of that it occurs: the temperature of the colder object became to rise when at the same time the temperature of the warmer object became to decrease. The process is continuing until the energy of these objects became equal, i.e. when their temperatures are equal.

Convection: Is the process of transferring the thermal energy trough the movement of a gas or liquid (fluid).

For example: if you turn on the electric fan oven the temperature in the room is increasing.

Radiation: Is the process of heat transfer by radiant energy that travels through by electromagnetic waves.

This is the way by which the Earth receive heat from the