The Physics Codex
The most complete, sourced, and machine-readable reference to the laws, concepts, and history of physics — from Newton to quantum fields. Every claim cited. Every equation derived. Three reading levels on every page.
Every entry in The Physics Codex is written at three levels — Curious, for a reader meeting a concept for the first time; Exploring, for the undergraduate or educator who wants working detail; and Deep Dive, for the researcher who needs full formalism and primary citations. No content is hidden behind a paywall or an account. Nothing here is advice — this is documentation of what verified sources record. See the full disclaimer.
Domains
Classical Mechanics
Kinematics, Newton's laws, energy, momentum, rotational motion, and oscillations.
55 entries plannedThermodynamics & Statistical Mechanics
Laws of thermodynamics, entropy, heat engines, kinetic theory, and statistical ensembles.
48 entries plannedElectromagnetism
Electric and magnetic fields, Maxwell's equations, circuits, and electromagnetic waves.
60 entries plannedQuantum Mechanics
Wavefunctions, the Schrödinger equation, spin, entanglement, and interpretations.
65 entries plannedSpecial & General Relativity
Spacetime, Lorentz transformations, the equivalence principle, and Einstein's field equations.
40 entries plannedNuclear & Particle Physics
Radioactivity, nuclear structure, the Standard Model, and fundamental forces.
55 entries plannedCondensed Matter Physics
Crystal structure, band theory, superconductivity, and phases of matter.
50 entries plannedAstrophysics & Cosmology
Stellar evolution, black holes, dark matter, dark energy, and the Big Bang.
52 entries plannedOptics & Photonics
Reflection, refraction, interference, diffraction, and laser physics.
38 entries plannedWaves, Acoustics & Oscillations
Wave mechanics, sound, resonance, and the physics of oscillating systems.
32 entries plannedAtomic & Molecular Physics
Atomic structure, spectroscopy, chemical bonding physics, and molecular energy levels.
40 entries plannedHistory, Philosophy & Foundations
The development of physical theory, foundational debates, and the philosophy of physics.
35 entries plannedCross-Cutting Sections
Constants Reference
All CODATA 2022 values, machine-readable.
Equations Library
Every named equation, derived and indexed.
Physicist Biographies
50+ figures across the history of physics.
Simulations
Interactive browser-based visualisers.
Glossary
80+ terms, defined precisely.
Learning Paths
Guided sequences through related entries.
What Makes This Different
Wikipedia is broad but inconsistently cited, with no derivations and no reading levels. HyperPhysics is comprehensive but has no machine-readable layer and is not actively maintained as a citable source. Khan Academy is excellent pedagogy but has no graduate-level content and no primary sourcing. MIT OpenCourseWare is excellent course material but has no unified reference structure.
The Physics Codex combines complete coverage from introductory to graduate level, full derivations for every named equation, primary-source citation for every claim, machine-readable JSON for every entry, and three simultaneous reading levels on every page. No existing resource does all five at once.