Thermal Physics
Temperature, heat and the laws of thermodynamics, explained both from the macroscopic laws and from the statistics of atoms: macrostates and microstates, fluctuations and the arrow of time with the Ehrenfest urn model; the zeroth law, thermometers, the ideal-gas and kelvin scales and the 2019 definition of the kelvin through the Boltzmann constant; heat, work, internal energy and the first law, quasistatic processes, heat capacities and the adiabatic law; kinetic theory of the ideal gas, the meaning of temperature, the Maxwell speed distribution and a collision simulation that produces it, mean free paths and the van der Waals gas; heat capacities of gases and solids, freezing out of rotation and vibration, the Einstein and Debye models, latent heat and the phase diagram of water; conduction, convection and radiation, thermal resistance of walls, Newton cooling, the Stefan–Boltzmann, Wien and Planck laws; the Kelvin–Planck and Clausius statements of the second law, Carnot's theorem, engine efficiencies and the performance of refrigerators and cold-climate heat pumps; entropy, the Clausius inequality, entropy changes in heating, phase changes, free expansion and mixing, and lost work; enthalpy, free energies and Maxwell relations, the critical point and equal-area construction for a van der Waals fluid and the Clausius–Clapeyron equation; counting microstates of Einstein solids, Boltzmann's entropy and the statistical definition of temperature, with the Sackur–Tetrode entropy of an ideal gas; the Boltzmann distribution, partition functions, two-level systems, equipartition, atmospheric structure and escape; and a capstone on the energy balance and greenhouse effect of the Earth, climate sensitivity, the luminosity and negative heat capacity of stars, the entropy budget of life and Landauer's limit on erasing information, with runnable Python examples throughout.
PHYS-261 Year 2 3 credits 12 lessons · 4 h 38 min ▶ Video lessons coming soon
Offered by HSM University · Physics
This is the Canadian version of this course. See the American version.
What you'll learn
- Distinguish macrostates from microstates, explain how the approach to equilibrium and the arrow of time arise from counting, and estimate the size of thermal fluctuations.
- State the zeroth law, explain how thermometers and the kelvin scale are defined, including the 2019 redefinition through the Boltzmann constant, and convert between temperature scales.
- Apply the first law of thermodynamics to quasistatic processes in ideal gases, calculating work, heat and internal energy changes, and derive and use the adiabatic law \(PV^\gamma = \text{constant}\).
- Derive the pressure of an ideal gas from kinetic theory, interpret temperature as mean molecular kinetic energy, and use the Maxwell speed distribution and the mean free path.
- Explain heat capacities of gases and solids using equipartition, freezing out and the Einstein and Debye models, and solve problems involving latent heat and phase diagrams.
- Calculate heat flow by conduction, convection and radiation, including thermal resistances in series, Newton cooling, the Stefan–Boltzmann law and Wien's law.
- State the Kelvin–Planck and Clausius forms of the second law, prove Carnot's theorem, and compute efficiencies of engines and coefficients of performance of refrigerators and heat pumps.
- Define entropy through the Clausius inequality, calculate entropy changes for heating, phase changes, ideal gases, free expansion and mixing, and relate entropy generation to lost work.
- Use the enthalpy and the Helmholtz and Gibbs free energies with their natural variables, derive and apply Maxwell relations, and analyse the van der Waals gas and the Clausius–Clapeyron equation.
- Count microstates of an Einstein solid, explain why the most probable macrostate dominates, and use \(S = k\ln\Omega\) and \(1/T = \partial S/\partial U\) to derive thermodynamic results.
- Derive the Boltzmann distribution and use the partition function, equipartition and the Maxwell distribution to compute heat capacities, populations, atmospheric structure and escape.
- Apply thermal physics to the Earth's energy balance and greenhouse effect, climate sensitivity, stellar luminosity and structure, the entropy budget of life and Landauer's limit on computation.
Course content
12 lessons · 4 h 38 min total · final exam
- 1 Why thermal physics: from steam engines to the arrow of time 25 min · quiz
- 2 Temperature, thermometry and the zeroth law 23 min · quiz
- 3 Heat, work and the first law of thermodynamics 23 min · quiz
- 4 Ideal gases and kinetic theory 23 min · quiz
- 5 Heat capacity, phase changes and latent heat 23 min · quiz
- 6 Heat transfer: conduction, convection and radiation 22 min · quiz
- 7 The second law: heat engines, refrigerators and Carnot 22 min · quiz
- 8 Entropy and irreversibility 23 min · quiz
- 9 Thermodynamic potentials and Maxwell relations 23 min · quiz
- 10 The statistical interpretation: microstates, multiplicity and Boltzmann's entropy 23 min · quiz
- 11 The Boltzmann distribution, equipartition and the Maxwell speed distribution 23 min · quiz
- 12 Capstone: thermal physics of the Earth, stars and life 25 min · quiz
- E Final exam 20 questions
Requirements
Recommended background. You can start any course at any time.
Description
Temperature, heat and the laws of thermodynamics, explained both from the macroscopic laws and from the statistics of atoms: macrostates and microstates, fluctuations and the arrow of time with the Ehrenfest urn model; the zeroth law, thermometers, the ideal-gas and kelvin scales and the 2019 definition of the kelvin through the Boltzmann constant; heat, work, internal energy and the first law, quasistatic processes, heat capacities and the adiabatic law; kinetic theory of the ideal gas, the meaning of temperature, the Maxwell speed distribution and a collision simulation that produces it, mean free paths and the van der Waals gas; heat capacities of gases and solids, freezing out of rotation and vibration, the Einstein and Debye models, latent heat and the phase diagram of water; conduction, convection and radiation, thermal resistance of walls, Newton cooling, the Stefan–Boltzmann, Wien and Planck laws; the Kelvin–Planck and Clausius statements of the second law, Carnot's theorem, engine efficiencies and the performance of refrigerators and cold-climate heat pumps; entropy, the Clausius inequality, entropy changes in heating, phase changes, free expansion and mixing, and lost work; enthalpy, free energies and Maxwell relations, the critical point and equal-area construction for a van der Waals fluid and the Clausius–Clapeyron equation; counting microstates of Einstein solids, Boltzmann's entropy and the statistical definition of temperature, with the Sackur–Tetrode entropy of an ideal gas; the Boltzmann distribution, partition functions, two-level systems, equipartition, atmospheric structure and escape; and a capstone on the energy balance and greenhouse effect of the Earth, climate sensitivity, the luminosity and negative heat capacity of stars, the entropy budget of life and Landauer's limit on erasing information, with runnable Python examples throughout.
Part of the Science stream, typically taken in year 2.