The whole of physics,
derived in the open.
Every assumption is declared before it is used. Every step is justified — not just stated. Every result is told where it stops being true. The one-stop reference for students learning it the first time and working scientists checking it the last.
Open the curriculum → See a specimen page
Three ways in
Follow the curriculum
Twenty-four units across four years, ordered so each result rests only on what came before. Start at mechanics, arrive at fields.
Find one thing fast
Search by result, symbol, or law. Land on the exact derivation, see what it assumes, and check where it breaks.
Trace a concept thread
Watch one idea — force, energy, symmetry — recur across the whole degree, from Newton's second law to Noether's theorem.
The difference, shown not told
Most textbooks hand you the answer. We show you the fine print it depends on — taken here from the Euler–Lagrange derivation, D-001.
Fixed endpoints
The path is varied while its start and end points are held fixed, so the boundary term [ ∂L/∂q̇ · δq ] vanishes at both limits.
Drop it — allow the endpoints to move — and that boundary term survives. You no longer get Euler–Lagrange alone; you get transversality conditions too. The "law" quietly had a domain all along.
Where this result stops being true
- The Lagrangian depends explicitly on higher derivatives q̈ — the variation must be redone.
- Constraints are non-holonomic — use Lagrange multipliers instead.
- The action is not differentiable in q (impacts, kinks).
- The configuration space is not a smooth manifold — the calculus of variations assumes one.
Where students stall — Wave 1 is live
The three units that trip people up most, verified end to end and open to read now.
Analytical Mechanics
Lagrangian and Hamiltonian formulations — the leap from forces to action that most degrees rush.
Electromagnetism
Maxwell's equations built from the field concept up, with every gauge choice made explicit.
Quantum Mechanics
From the Schrödinger equation to operators and measurement — the postulates stated plainly, then earned.