Microscopic Thermal Physics
Microscopic Thermal Physics
Aims and Objectives
General aims:
- 1. To revise basic concepts of heat, temperature, work and energy in thermal systems.
- 2. To relate microscopic and macroscopic descriptions of thermal systems and to demonstrate the statistical nature of the microscopic approach.
- 3. To relate the arguments underlying the derivation of the Maxwell-Boltzmann energy distribution and to demonstrate the widespread applicability of the concepts involved in many diverse areas of physics.
- 4. To investigate further properties of ideal gases.
- 5. To examine diffusion and thermal conductivity from a statistical viewpoint.
Section 1. Introduction to macroscopic thermal variables - 1 lecture
Objectives: On completion of this section you should be able to:
- 1. Express the meanings of “heat”, “temperature”, “work” and “internal energy”.
- 2. To select appropriate conjugate variables to describe a given thermal system.
- 3. State the First Law of Thermodynamics.
- 4. Derive expressions for the work done in thermodynamic processes.
- 5. Explain what is meant by an “equation of state” and give suitable examples.
Section 2. Statistical concepts in thermodynamics - 3 lectures
Objectives: On completion of this section you should be able to:
- 1. Distinguish between microscopic and macroscopic variables.
- 2. Explain the relative probability of different microscopic configurations.
- 3. Explain why microscopic states can only be treated statistically.
- 4. Discuss the relationship between microscopic states and macroscopic variables.
- 5. Illustrates this relationship with a suitable example.
- 6. Describe the meaning of thermodynamic equilibrium from both the microscopic and macroscopic viewpoints.
- 7. Discuss the reversibility of thermodynamic processes from a microscopic viewpoint.
- 8. Discuss the idea of entropy from a statistical viewpoint.
Section 3. Boltzmann’s Law for the distribution of energies and related quantities in thermal systems - 3 lectures
Objectives: On completion of this section you should be able to:
- 1. State the ideal gas law.
- 2. Derive equations describing the mean kinetic energy of molecules in an ideal gas.
- 3. Relate the temperature of a thermal system to the microscopic description of the system.
- 4. Explain why molecules of an ideal gas have a distribution of energies and velocities.
- 5. Describe the general form of the energy distribution and identify the Boltzmann factor.
- 6. Discuss the distribution of velocities of an ideal gas, and the temperature dependence of this distribution.
- 7. Express the meaning of thermodynamic degrees of freedom.
- 8. State the “equipartition of energy” theorem.
- 9. Apply the Maxwell-Boltzmann energy distribution to examples in several diverse areas of physics.
Section 4. Further properties of ideal gases - 3 lectures
Objectives: On completion of this section you should be able to:
- 1. State Dalton’s Law of partial pressures and apply it in appropriate situations.
- 2. Derive molar specific heats cP and cV
of an ideal gas and show that cP - cV = R.
- 3. Demonstrate that pVg
is a constant in a adiabatic expansion of an ideal gas.
- 4. Discuss the Second Law of Thermodynamics with examples.
Section 5. Molecular processes - 3 lectures
Objectives: On completion of this section you should be able to:
- 1. Define “mean free path” and “drift speed”.
- 2. Derive an expression for mean free path.
- 3. Explain what “Brownian motion” is and how it provides evidence of the distribution of molecular energies.
- 4. Explain the process of diffusion.
- 5. Employ statistical arguments to derive an expression for the mean rate of spread of molecules due to diffusion.
- 6. Discuss the process of thermal conductivity.