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PX121 Thermal Physics I

Lecturer: Neil Wilson

Weighting: 6 CATS



The module introduces kinetic theory and the methods of classical thermodynamics. These can be used to determine the behaviour of certain physical parameters in a model-independent fashion, using only the results of experimental measurements of other physical quantities. The results of thermodynamics are fundamental to physics and will be used in later years in the description of all forms of matter and energy.


At the end of the module you should

  • Be familiar with solid, liquid and gas phases of matter and how their properties depend on thermal motion and the forces between atoms and molecules.
  • Have a working knowledge of the kinetic theory of gases and how this relates to what is actually observed in real gases
  • Be able to explain and use the first and second laws of thermodynamics to solve some simple problems concerned with heat and work changes in systems. You should know the fundamental limits for the efficiency of heat engines, and be able to derive the thermodynamic temperature scale from the operation of an ideal Carnot heat engine.


Heat and Temperature
The zeroth law of thermodynamics: thermal equilibrium, thermometry and temperature scales.
Thermal expansion
Heat capacity and phase changes
Heat transport.

Modelling of ideal gases
Equations of state and isotherms
Kinetic model of gases
Equipartition of energy and heat capacities
Interactions and the condensed phases

First law of thermodynamics.
Thermodynamic systems and processes
Internal energy and heat capacity
Adiabatic processes

Second law of thermodynamics.
Reversible and irreversible processes
Heat engines: petrol engine (Otto cycle), refrigerators and heat pumps
Second Law: Clausius and Kelvin- Planck statements
Carnot cycles and Carnot heat engines
Entropy and entropy changes

Commitment: 15 Lectures + 3 problems classes

Assessment: 1 hour examination

Recommended Text: H D Young and R A Freedman, University Physics, Pearson.

Leads from: A level Physics and Mathematics

Leads to: PX265 Thermal Physics II