Free physics notes
Physics, explained chapter by chapter
Notes that cover the concepts, work through the derivations, and show the results — with diagrams, typeset equations, and simulations you can try yourself.

“All my life through, the new sights of Nature made me rejoice like a child.”
Marie Curie1867–1934 · RadioactivityPierre Curie, 1923
Photograph by Henri Manuel, c. 1920s. Public domain.
Curriculum
The six branches of physics
Each branch is divided into chapters meant to be read in order, since later chapters build on earlier ones. Mechanics is available now; the remaining branches are in progress.
- 01
Mechanics
- 02
Oscillations & Waves
- 03
Thermodynamics
- 04
Electrodynamics
- 05
Optics
- 06
Modern Physics
Inside a chapter
What every chapter includes
Step-by-step derivations
Every result is derived from stated assumptions, so you can follow each step instead of taking it on trust.
Clearly typeset equations
Math is typeset with KaTeX, so it stays sharp, selectable, and readable at any size.
Diagrams and video
Labelled figures for the geometry, plus a video explanation where watching is easier than reading.
Interactive simulations
Simulations sit next to the theory, so you can change one variable and see how the rest responds.