Course Content

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UBC Physics 203 lecture-by-lecture schedule

 
Date
Deadlines, tests and reminders
In-class topics and materials
Textbook readings
Things to do after class
Lecture
1
Tue
11/01
 
  • Course organization and syllabus
  • What is Thermal Physics?
  • Binomial coefficient distribution (worksheet)
  • Probability distribution of a large number of independent random variables: the central limit theorem
Intro slides
Worksheet 1: Binomial coefficients
Jupyter file: the coin toss experiment

Watch: The Galton Board YouTube video: another way to think about binomial coefficients
Schroeder 2.1 Read the course Syllabus.

Another great YouTube video (by 3Blue1Brown) on Binomial distributions. The details relevant to us start at 5:40 if you want to skip ahead.

Finally, if you are looking for a very basic intro to probability concepts, you can try this chapters 1 and 3 from this online textbook (highschool level) available from wikibooks.
Lecture
2
Thu
13/01
 
  • Finish Worksheet 1
  • Interactions: atoms moving between containers; energy moving between atoms
Lecture notes, including slides and clicker questions with answers

Worksheet 1 solution files: Jupyter code and output with some extra explanations and summary slides with answers and some more explanations.

Solutions to the optional page of WS1.
We are covering this material in different order than the book. Don't worry if the details don't make sense to you yet, we will get to them.

Schroeder 2.3 talks conceptualy about the same things as the lecture, but uses a different example (the Einstein solid, section 2.2) that we have not covered yet.

You can read 2.3 for review of the concepts, or 2.2 and 2.3 together to get a more detailed view.
Work on the first Weekly Practice on WeBWorK (opens a new tab; you must be logged into Canvas to have this link take you to your Phys 203 WebWork).  
Lecture
3
Tue
18/01
Weekly Practice 1 is due before class (9am).
  • Thermal equilibrium
  • Thermodynamic limit
  • Macrostates, microstate, multiplicity
Lecture notes, including clicker questions and answers
Schroeder 2.1-2.3, for definitions mostly  Weekly Practice 1 solutions  
Lecture
4
Thu
20/01
 
  • Temperature and beta
  • Probabilities and the Boltzmann factor
  • Partition function
Lecture notes
Practice with Boltzmann factors
Schroeder 6.1, 6.2 (pages 229-230 only)
  :-)
  Friday Jan 21 (tomorrow) is the last day to withdraw from a course without a W standing. EDIT: This deadline has moved. To withdraw from the course after Jan 21, contact Faculty of Science advising office.
Lecture
5
Tue
25/01
Weekly Practice 2 is due before class (9am).  
  • Average energy
  • Microscopic model of pressure
  • Ideal gas law (derivation)
  • Thermodynamics and functions of state
  • Functional definition of temperature and a gas thermometer
  • Equipartition theorem
Lecture notes
Schroeder 1.1, 1.2, 6.3
Note on Schroeder's approach vs our approach:
Since we were able to include the result of section 6.3 (average energy of a free, non-relativistic particle, equation (6.40)), we were able to derive the ideal gas law, rather than assume it the way the book does on page 12

Schroeder 1.3, 1.4, 1.5 (up to page 22)
Weekly Practice 2 solutions

Start working on Problem Set 1  
Lecture
6
Thu
27/01
 
    *** start of material for test 2***
  • More on the equipartition theorem (details and clicker questions from last lecture notes)
  • Work
  • Ideal gas and work: worksheet 2, parts 1 and 2
    *** end of material for test 1***
Worksheet 2: Compression work for ideal gas
Worksheet 2 solutions, parts 1 and 2 (full solutions available with next lecture)
Lecture notes
Schroeder 1.4, 1.5, 1.6  
Lecture
7
Tue
01/02
Weekly Practice 3 is due before class (9am).
  • Heat capacity: first look, ideal gas only
  • Finish WS2: part 3 work for an adiabatic curve
  • How a car engine works
  • Heat engines basic concept: efficiency
Animation
Worksheet 2 solutions (full)
Worksheets 3 and 4: Heat engines
Lecture notes
Schroeder 4.1 (up to and including equation (4.1) + figures 4.1, 4.2 and 4.3) Weekly Practice 3 solutions  
Lecture
8
Thu
03/02
Test 1: it will cover lectures 1-6, together with appropriate sections from Schroeder as listed above, worksheets 1-2 and Weekly Practice assignments 1-3.

This table of constants from Schroeder will be provided with the test.
  • Test 1: 9am-10am (50 minutes + 10 minutes for uploads etc...). Invigilated via Zoom.

  • Heat capacities (in general) and latent heat
  • Heat engine example: Carnot cycle with ideal gas
Lecture notes
Schroeder 4.3 (section on internal combustion engines only) Solutions to Test 1 (problems) (Answers to the multiple choice questions can be accessed directly from the Canvas test 1 quiz). 
Monday, Feb 7: Return to in-person learning.   (Current as of Jan 26, 2022)
Lectures will take place in Henn 200.
Lecture
9
Tue
08/02
Weekly Practice 4 is due before class (9am).

Problem Set 1 is due at 4pm.  
  • Worksheet 3
  • Worksheet 4, qualitative analysis
  • WS 4 computation (skipped)
  • The Otto cycle efficiency: Worksheet 4 extension (skipped for now)
  • Intensive vs extensive quantities
  • A bit of a review: microstates, macrostates, fundamental assumption of Statistical Mechanics, the Law of Increase of Multiplicity, thermodynamic limit, beta and temperature
Worksheets 3 and 4: Heat engines
Lecture notes
Worksheet 3 solutions
Solutions to WS 4


WS4 extension, Otto cycle questions
Solutions WS 4, Otto cycle questions
Schroeder 2.3
Schroeder 2.4 (page 60 only)
Schroeder 2.6 (up to page 77)
Schroeder 3.1
Schroeder 3.2 (section on The Macroscopic View of Entropy only)
Schroeder: Extensive end Intensive Quantities, pg 163-164
Weekly Practice 4 solutions

Problem Set 1 solutions  
Lecture
10
Thu
10/02
 
  • Entropy and the Second law of thermodynamics
  • Connection between entropy and heat capacities
  • Reversible and irreversible processes, examples
  • Pressure as a derivative of internal energy
  • The (fundamental) thermodynamic identity
Lecture notes
A brief note on some calculus
Schroeder 3.4
Schroeder 2.6 (reversible and irreversible processes)
 
Lecture
11
Tue
15/02
Weekly Practice 5 is due before class (9am).  
  • Entropy of the ideal gas
  • Mixing and entropy, entropy of mixing, identical particles
Lecture notes
Schroeder 2.6 (entropy of an ideal gas) Schroeder 2.4 (pg 60-62)
Schroeder Fig 2.10 and the second sentence underneath
Schroeder 2.6 (entropy of mixing)

+ Schroeder 2.5 (section of Multiplicity is covered on the Worksheet, section on Interacting gases is similar in spirit to PS1, Q3 and PS2, Q4)
Weekly Practice 5 solutions  
Lecture
12
Thu
17/02
 
  • Approximations, Stirling's Approximation
  • Multiplicity of the ideal gas
  • The paramagnet in microcannonical ensemble (WS5, part 1)
    *** end of material for test 2***
Lecture notes
Worksheet 5: quantum systems in microcannonical ensemble
Worksheet 5, part 1, solutions
Useful facts about Quantum Mechanics

Optional Worksheet : Multiplicity of the ideal gas
Solutions for the optional Worksheet
Schroeder 2.1
Schroeder 3.3
Schroeder 2.2
 
Mid-term break (Feb 21-25). Monday Feb 21 is Family Day and UBC is closed.
Lecture
13
Tue
01/03
Weekly Practice 6 is due before class (9am).

Problem Set 2 is due at 4pm.  
  • Brief review of the material so far (test 2 concept review)
  • Worksheet 5, part 2 (Einstein solid)
    *** start of material for test 3***
  • Helmholtz free energy F: introduction
Worksheet 5 solutions (both parts)
Lecture notes  
Schroeder 2.4 (pages 63-66: the book computes the multiplicity of the Einstein solid in the high temperature limit only, which makes the Stirling approximation harder to use; section on sharpness is similar in spirit to PS1, Q3 and PS2, Q4)
Schroeder 1.6 (enthalpy)
Schroeder 5.1 (up to page 155)
Weekly Practice 6 solutions

Problem Set 2 solutions  
Lecture
14
Thu
03/03
Test 2: it will cover lectures 6-12 (the first half of lecture 13 is a useful review), together with appropriate sections from Schroeder as listed above, worksheets 3 and 5 (Part 1) and Weekly Practice assignments 4-6

Practice material is posted on Canvas

You might find the following formula sheet useful: page of formulas and data (it will be included with the test).
  • Test 2: 9am-10am

  • Enthalpy H and Gibbs free energy G
  • Free energy as available work
  • Chemical reactions and batteries (as applications)
Lecture notes (including a summary of how/when to use H, F and G to think about work and heat)
Solutions to Test 2

Friday Mar 4 (tomorrow) is the last day to withdraw from a course (with a W standing).  
Lecture
15
Tue
08/03
Weekly Practice 7 is due before class starts (9am)
  • Thermodynamic identities
  • Maxwell relations
  • Free energy wants to be minimized
  • Pressure from free energy
  • Chemical potential and diffusive equilibrium
  • Thermodynamic identities with change in number of particles
  • Gibbs free energy and chemical potential
Worksheet 6 : thermodynamic potentials meet calculus
A simple proof showing that partial derivatives commute, needed for Maxwell relations (worksheet 6)
Worksheet 6 solutions
Lecture notes
Worksheet 7 : thermodynamic potentials meet chemical potential and calculus
Worksheet 7 solutions
Schroeder 5.1 (Thermodynamic Identities)
Schroeder 5.2
Schroeder 3.5 (for chemical potential)
Weekly Practice 7 solutions

If you want to know more about the mathematics of Legendre transform, check out this article
Lecture
16
Thu
10/03
 
  • Phase transitions and phase diagrams
  • Phase transitions and Gibbs free energy
  • Clausius-Clapeyron relation
Lecture notes
Schroeder 5.3 (pg 166-169, Clausius-Clapeyron)  
Lecture
17
Tue
15/03
Weekly Practice 8 is due before class starts (9am) 
  • Example: boiling water (worksheet 8)
  • Vapour equation, vapour partial pressure and humidity
  • More on phase transitions:
    • graphite and diamond
    • nucleation and boiling (optional)
    • superheated and supercooled water (optional)
Worksheet 8: Boiling water
Worksheet 8 solutions
Lecture notes
More (optional) material in the lecture notes: The van der Waals equation and a model of gas-liquid phase transitions
Schroeder 5.3 (except for van der Waals model)

Water behaving weirdly:
Behaviour of water at its triple point: youtube video
Supercooled water: youtube video Superheated water: youtube video

One more phase diagram video, this time with nitrogen and its triple point: youtube video
Weekly Practice 8 solutions
Lecture
18
Thu
16/03
 
  • Heat engines: the general set-up and theory
  • Heat engines on a T-S diagram (not in the book!)
  • Refrigerators and the COP
  • Real refrigerators and throttling (Joule-Thomson effect)
    *** end of material for test 3***
Lecture notes
Schroeder 4.1, 4.2
Schroeder 4.3 (except for steam engine)
Schroeder 4.4
 
Lecture
19
Tue
22/03
Weekly Practice 9 is due before class starts (9am) 
  • The steam engine (Worksheet 9)
  • COP of a real refrigerator

    Back to stat mech: chapters 6 and 7

  • Review of cannonical approach to stat mech from the beginning of course
    • Boltzmann factor and probabilities
    • Partition function
    • Spectrum, multiplicities
  • Average energies (magic formula)
Lecture notes
Worksheet 9: the steam engine

Worksheet 9 full solutions (the order of questions on this version is different, but the questions/answers are all there).
Schroeder 4.3 (steam engine)   Weekly Practice 9 solutions
Lecture
20
Thu
24/03
Test 3: it will cover lectures 13-18, together with appropriate sections from Schroeder as listed above, worksheets 6-8 and Weekly Practice assignments 7-9.

Practice material is available on Canvas.

You might find this page of formulas and data. useful (it will be included with the test).
  • Test 3: 9am (length: 1 hour)

  • Partition function and (Helmholtz) free energy
  • Average energy at fixed temperature (cannonical ensemble), example: paramagnetism
  • Partition function of composite systems (distinguishable particles)
Lecture notes
Worksheet 10: Averages and composite systems
Worksheet 10 solutions
Another optional Worksheet: Free energy from the partition function
Solutions for the optional Worksheet
Schroeder 6.1
Schroeder 6.2 (without paramagnetism or rotation of diatomic molecules sections)
Schroeder 6.5 (details of the proof are optional, presented in the optional Worksheet)
Solutions to Test 3

 
Lecture
21
Tue
29/03
Weekly Practice 10 is due before class (9am) 

Problem Set 3 is due at 4pm.
  • Continuous random variables and the probability density
  • Proof of the equipartition theorem (again)
  • Speed distribution for a particle in one dimension
  • Speed distribution for a particle in three dimensions (Maxwell Speed Distribution)
Lecture notes
Worksheet 11: Speed distribution in a 3D gas
Worksheet 11 solutions
Schroeder 6.2 (without rotation of diatomic molecules section)
Schroeder 6.3
Schroeder 6.4
Plots of the Maxwell distribution (useful for Weekly Practice 11)

Weekly Practice 10 solutions

Problem Set 3 solutions  
Lecture
22
Thu
31/03


 
  • Partition functions of distinguishable vs indistinguishable particles
  • Partition function of a dilute composite system of N indistinguishable particles
  • The partition function and thermodynamics of the ideal gas
Worksheet 12: ideal gas in a cannonical ensemble
Worksheet 12 solutions
Lecture notes
Schroeder 6.6, 6.7

(The textbook does a fully quantum mechanical treatment of the ideal gas in equations (6.75)-(6.79), before changing the sum to an integral which in effect takes the classical limit. This technique is not required material for the course.)
 
Lecture
23
Tue
05/04
Weekly Practice 11 due before class starts (9am) 
  • More on indistinguishable particles
  • Bosons and fermions
  • The Gibbs factor and the grand partition function
  • The Fermi-Dirac distribution (page 1 of Worksheet 13)
  • The Bose-Einstein distribution (page 2 of Worksheet 13)
Lecture notes
Worksheet 13: FD and BE distributions
Worksheet 13 solutions
Schroeder 7.1, 7.2 Weekly Practice 11 solutions 
Lecture
24
Thu
07/04
 
  • Density of normal modes
  • Density of states
  • Quantum gases (applications of FD and BE distributions):
    • Noninteracting fermion gas at T=0 (Worksheet 14, page 1)
    • Metals, electron bands, insulators, semiconductors
    • Blackbody radiation (Worksheet 14, page 2)
    • The Earth and the Sun (Worksheet 14, page 3, optional)
Sample normal modes animation
Lecture notes

Worksheet 14: Quantum gases (we only covered pages 1 and 2) Worksheet 14 solutions
Black body radiation simulation

Worksheet 15: Degenerate electron gas (optional, a much extended version of page 1 of worksheet 14)
Worksheet 15 solutions

Another optional worksheet: Computing densities of states
Solutions for the optional Worksheet above
Schroeder 7.4
Schroeder 7.3 (selected)
Quantum gases (photons and electrons) practice: (Weekly Practice 13 and the old Problem Set 5, not for credit, and the solutions), focusing on Black Body Radiation and the cold non-interacting fermion gas

Tomorrow, Fri April 8, is last day of classes   

Problem Set 4 is due on April 20. Solutions will be posted on April 21 (see below).
Exam period is April 12-27 inclusive, including Saturdays and Sundays.
Our exam has been scheduled for April 27 at noon.
UBC will be closed Friday April 15 and Monday April 18 for Easter long weekend.
After
classes
end
Weekly Practice 12 is an optional, bonus WW due Tuesday April 12. The grade will be used to replace a lower scoring WW (if any).
Weekly Practice 12 solutions

Problem Set 4 is due on April 20 (extended deadline). Problem Set 4 solutions posted April 21.

Test 2 and 3 reflection assignments are due anytime before the final exam.

Final Exam info and study materials.

Monday office hours will continue (Zoom, 3:30-4:30 pm). Information on additional pre-exam office hours and TA help sessions will be available on Canvas (check the Announcements).
Final
Exam
Wed
27/04
Time: 12:00 (noon)
Duration: 2.5 hours
Location: LSK 201
Format: Similar to the Tests

A formula sheet will be provided. Reviewing practice material posted on Canvas (link above) is strongly recommened.