Physics Simulations

Free, interactive physics labs that run entirely in your browser — no sign-up, no downloads, nothing uploaded. Watch order emerge in Conway's Game of Life, launch planets in a gravity simulator, set a double pendulum spinning into chaos, trace a clean sine wave in simple harmonic motion, build interference fringes in the double-slit experiment, bounce a pulse along a string, pour sand and fire in a cellular playground, stir a real-time fluid, and dive into chaos and complexity with the Lorenz attractor, the bifurcation diagram, reaction-diffusion patterns and a charged particle in a magnetic field. Every lab is embeddable on your own site.

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Conway's Game of Life

The famous cellular-automaton sandbox. Draw cells or drop in gliders, guns and oscillators, then watch complex patterns evolve from four simple rules.

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Gravity Orbit Simulator

Newtonian gravity you can play with. Load the Sun–Earth–Moon, a binary star or the chaotic three-body problem, then fling in new planets and watch their trails.

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Double Pendulum

A textbook example of deterministic chaos. Set two pendulums a hair apart and watch identical rules send them onto wildly different paths.

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Simple Harmonic Motion

The smoothest motion in physics. Release a mass on a spring or a simple pendulum and watch it draw its own sine wave, trade energy back and forth, and reveal where "simple" breaks down.

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Double-Slit Experiment

The famous "only mystery" of quantum mechanics. Fire waves or single photons through two slits and watch interference fringes build up dot by dot — then close a slit and watch them vanish.

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Wave on a String

The simplest travelling wave. Send a pulse and watch it reflect — flipping at a fixed end, staying upright at a free one — or drive the end steadily until the string locks into a standing wave.

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Falling Sand

A cellular-automaton powder toy. Paint sand, water, oil, fire and smoke and watch them pile, flow and burn — water douses fire, fire races along oil, sand sinks through water.

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Fluid Simulation

Stir a real-time fluid with your mouse. A stable Navier–Stokes solver swirls dye and velocity across the grid — mesmerising, and surprisingly physical.

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Lorenz Attractor

The iconic butterfly of chaos theory, in rotatable 3D. A trajectory that never repeats yet stays forever on the same strange surface — nudge the start and watch two twins diverge.

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Bifurcation Diagram

Chaos theory's most famous picture. Sweep the logistic map's growth rate and watch one value split — 2, 4, 8 — into the period-doubling cascade, then zoom into the fractal.

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Reaction-Diffusion

Turing patterns growing in real time. Two diffusing chemicals react to paint spots, stripes, mazes and coral — the mechanism behind leopard spots and seashells. Paint your own.

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Charged Particle in a Magnetic Field

The Lorentz force made visible. Watch a charge circle in a magnetic field and drift under crossed fields — then switch to the dipole mode where particles spiral to the poles as the aurora.

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Twelve Ways to Watch Physics Happen

Each lab turns an equation into something you can poke at.

1

Emergence

In Conway's Game of Life, four rules on a grid of on/off cells produce gliders, guns and self-replicating structures — a classic demonstration that complexity can come from simplicity.

2

Gravity

The orbit simulator integrates Newton's law of gravitation between every body, so stable orbits, slingshots and the unsolvable three-body problem all fall out of the same equation.

3

Chaos

The double pendulum is fully deterministic yet unpredictable: a microscopic change in the starting angle completely changes where it ends up. Run two side by side to see it.

4

Oscillation

The simple harmonic motion lab is the calm counterpart to chaos: a mass on a spring or a pendulum draws a clean sine wave, its period set only by the physics and never by how far you pull it.

5

Interference

The double-slit experiment sends waves — or single photons — through two slits, and their overlap paints bright and dark fringes. Fire particles one at a time and the same pattern builds from thousands of random dots.

6

Reflection

The wave on a string sends a pulse down a string and bounces it back — inverted at a fixed end, upright at a free one — or drives the end into a standing wave of fixed nodes and swinging antinodes.

7

Powders

The falling sand playground is another cellular automaton: paint sand, water, oil and fire and watch simple per-cell rules pile, flow and burn — water dousing fire, sand sinking through water — all emerging from a few "if" statements.

8

Flow

The fluid sim solves a stable form of the Navier–Stokes equations every frame, letting you push velocity and dye around and watch vortices form.

9

Strange attractors

The Lorenz attractor traces a 3D path that never repeats or crosses itself, yet is forever trapped on a butterfly-shaped surface — the picture that gave us the phrase "the butterfly effect".

10

Routes into chaos

The bifurcation diagram shows exactly how order becomes chaos: turn up one parameter of the logistic map and a single steady state doubles to two, four, eight and then a chaotic blur, at the universal Feigenbaum rate.

11

Self-organisation

The reaction-diffusion lab lets two chemicals react and spread until they spontaneously break into spots and stripes — Alan Turing's proposed mechanism for the patterns on animal coats and seashells.

12

Fields and forces

The charged particle lab draws the Lorentz force: a charge circles in a magnetic field and drifts under crossed fields, and in dipole mode it spirals to the poles the way the solar wind lights up the aurora.