About this reference
An independent, fast-lookup reference for the natural sciences — organized as Module → Unit → Topic → Detail, with every equation numbered for citation (e.g. E1.3.2). Content, wording, structure and numbering are original; nothing is reproduced from any textbook.
Modules run F (Foundations), M (Mechanics), W (Oscillations and Waves), T (Thermal Physics), E (Electricity and Magnetism), O (Optics), and Q (Modern Physics), grouped under the Physics domain; cross-cutting reference material — constants and units, problem-solving patterns, a connection map between related entries, and notation — lives under Appendices instead. A unit F2 contains topics F2.1, F2.2 …; each topic's equations are numbered within it, so F2.2 might contain entries F2.2.1 and F2.2.2.
Every entry is tagged with what kind of statement it is — not what it's about, but how it's true:
- DefinitionA meaning assigned by choice, not discovered.
- ConventionAn arbitrary but standard choice (a sign, a reference point).
- LawAn empirical regularity of nature.
- PrincipleA foundational assumption a theory is built on.
- ResultDerived from other statements — provable, not measured.
- ModelA deliberate simplification with a stated domain of validity.
- ConstantA measured number of nature.
Every equation has its own page: statement, symbols and units, when it applies, a derivation ending on the statement itself, worked examples chosen to teach something beyond arithmetic, common traps, and links to connected entries — including across modules, such as Coulomb's law linking to Newton's law of gravitation.
This is a work in progress, actively growing. Corrections and gaps are expected at this stage; treat it as a fast reference, not a final authority.