Special Relativity
Lecture notes for From Classical to Modern Physics, PHYS20040
Preface
These pages form the lecture notes for the Special Relativity component of PHYS20040 - From Classical to Modern Physics. Keep an eye on these pages, as these notes will grow as the course progresses.
Errata and misunderstandings
If you discover any mistakes, no matter how small, please inform me via email or via the unit discussion boards. I would like to know about any typos, spelling mistakes, bad punctuation, etc. so that I can correct them for future students. If there is an error in the mathematics or physics, then definitely let me know — as a teacher, the last thing I want to do is confuse my students with bad mathematics.
If you find a part of the notes that you don’t understand, again feel free to contact me. I may be able to provide an alternative explanation that works better for you. Alternatively, I might be able to clarify that part of the notes or perhaps you have found an error in the notes without realising it. In any case, by requesting help to understand something in the notes, you may also be helping me to improve them.
I will endeavour to fix the lecture notes as any errors are found. Any recent edits will be listed below, so that you are alerted to any changes.
Updates
- (16th Sep 2025) Initial release.
- (3rd Oct 2025) Updated to include the Lorentz transformation, the invariant interval and Minkowski diagrams.
- (5th Oct 2025) Updated to include rapidity, momentum and energy.
Recent fixes and clarifications
- (29th Jan 2026) Fixed sentence in section 6.2 to read “momentum is conserved” rather than “momentum is converged”.
Recommended and suggested reading
While these lecture notes cover the contents of the course, I would strongly recommend some supplementary reading, perhaps to broaden your knowledge or merely to find alternative explanations for concepts you have difficulties with.
Core text
Chapters 11-13 of Introduction to Classical Mechanics With Problems and Solutions, by David Morin. The author not only provides clear explanations but also anticipates students questions, answering them in his “remarks”. This book is also a great source of classical mechanics problems (with worked solutions) and exercises (without). But beware: some of the problems are more than challenging, while the limericks might not be to your taste!
Unfortunately, this text is not available as an e-book. However, chapter 11 is available on the author’s website while the library has provided a scanned copy of Chapter 12 — find this in the unit resources. There are also a number of copies of this book in the library.
Suggesting reading
- Chapter 12, sections 1 and 2 of Introduction to Electrodynamics, by David J. Griffiths. You will undoubtedly be recommended this text for the Electromagnetism part of this unit and possibly for a part of Mathematical Physics too. You should be able to follow the first two sections of the special relativity chapter prior to studying electromagnetism, while you might wish to read section 12.3 after completing electromagnetism, to see how the two topics fit together. However, since this is only a single chapter, it is naturally more terse than the exposition in the core text.