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PhysicsDaily

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.

Start with the introductionBrowse the curriculum
Portrait of Srinivasa Ramanujan.
“An equation has no meaning for me unless it expresses a thought of God.”

Srinivasa Ramanujan1887–1920 · MathematicsAs recalled by S. R. Ranganathan, Ramanujan, the Man and the Mathematician, 1967

Photograph c. 1919, Cambridge University Library. 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.

  1. 01

    Mechanics

    2 chapters
  2. 02

    Oscillations & Waves

    Planned
  3. 03

    Thermodynamics

    Planned
  4. 04

    Electrodynamics

    Planned
  5. 05

    Optics

    Planned
  6. 06

    Modern Physics

    Planned

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.