Physics Experiments

Interactive, self-contained simulations of classic physics experiments. Each folder is an embedded web app — open it from the sidebar to launch full-screen.

Mechanics — how things move

• Galileo's Inclined Plane (inclined-plane/) — The 1604 experiment that broke Aristotle. Roll a ball down a tilted ramp, time the segments, watch distance grow as t² — proving constant acceleration before clocks could measure it directly.
• Brachistochrone (brachistochrone/) — Race three balls down straight, circular, and cycloid paths. The cycloid wins — every time. Bernoulli's 1696 puzzle.
• Projectile Motion (projectile-motion/) — Classical ballistics. Tune angle, velocity, and gravity; trace the parabola.
• Foucault Pendulum (foucault-pendulum/) — Paris, 1851. A 28 kg pendulum swings in the Panthéon and its plane appears to rotate — but it's the Earth turning underneath. Adjust latitude and watch the rotation period change.
• Pendulum Wave (pendulum-wave/) — 15 pendulums tuned to subtly different periods. Pull them in unison, watch chaos resolve into a standing wave, then back into chaos. Pure math, made visible.

Waves & light

• Double-Slit (double-slit/) — Wave-particle duality. Fire one photon at a time and watch an interference pattern emerge from individual hits. The experiment Feynman called "the only mystery."
• Wave Interference (wave-interference/) — Two coherent point sources on a ripple tank. Adjust separation and wavelength to reshape the pattern.

Quantum

• Stern-Gerlach Lab (stern-gerlach/) — Frankfurt, 1922. Send silver atoms through a non-uniform magnetic field. Classical physics predicts a smear; the screen shows two discrete spots. Spin is quantized. Now stack analyzers to discover the non-commutativity that built quantum mechanics.
• Millikan Oil Drop (millikan-oil-drop/) — Chicago, 1909. Suspend tiny charged oil droplets between charged plates, balance gravity against electric force, measure the charge. Find that every drop is an integer multiple of one number: e ≈ 1.602×10⁻¹⁹ C. Charge is quantized too.

Solid state

• Bragg X-ray Diffraction (bragg-diffraction/) — Cambridge, 1913 (Nobel 1915). Aim X-rays at a crystal, sweep the angle θ, watch peaks erupt only where 2d sin θ = nλ. The experiment that proved crystals are periodic lattices and gave us every structural-biology and materials-science result since. Toggle simple-cubic / BCC / FCC and see how the structure factor kills certain peaks.

Implementation notes

Each experiment is a directory with an index.html file plus a .app marker so Cabinet renders it full-screen. Built with vanilla JS + Canvas 2D — zero build step, zero external libs. Open any HTML file directly in a browser if you want to hack on it.

Why these ten

They cover the five moments physics changed:

1. Mechanics is mathematical (Galileo, Bernoulli, Newton via projectile motion)
2. The Earth moves (Foucault — physics confirms cosmology by direct demo)
3. Light is weirder than waves OR particles (double-slit, wave interference)
4. Reality is quantized (Stern-Gerlach for spin, Millikan for charge)
5. Matter is periodic (Bragg — and once you know that, every transistor follows)

Read the cabinet top-to-bottom and you've toured 350 years of physics in the order it actually happened.