For educators
Every simulation here runs entirely in the browser — no sign-up, no downloads, and no student data ever leaves the device. Embed them free in your course site or LMS, and assign the ready-made classroom worksheets that come with the core labs.
Motion & Gravity
Free Body Diagram Maker
Draw the forces on a body and solve them. Load a classic scenario or add your own arrows, drag to resize, and read the net force, equilibrium and acceleration live.
Open lab FreeInclined Plane
Rest a block on a ramp and split gravity into components. Change the angle and friction and watch it hold or break loose — with the weight, normal and friction arrows live.
Open lab FreeProjectile Motion Simulator
Launch a projectile and watch its parabola. Set the angle, speed and gravity, toggle air resistance, and read off the range, maximum height and flight time — or drag on the canvas to aim.
Open lab FreeCollision Simulator
Fire two carts together and watch momentum and energy trade hands. Set the masses, speeds and elasticity — from a perfectly elastic bounce to a dead-stop stick — and see momentum stay conserved.
Open lab FreeSimple 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.
Open lab FreeSimple Pendulum
The cleanest oscillation in physics. Release a single bob and watch it trace its arc, then compare the measured period with the ideal T = 2π√(L/g) as you widen the swing.
Open lab FreeDouble Pendulum
A textbook example of deterministic chaos. Set two pendulums a hair apart and watch identical rules send them onto wildly different paths.
Open lab FreeGravity Simulator
A gravity simulator 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 orbits and trails.
Open lab FreeBlack Hole
Gravity at its limit. Watch a Doppler-beamed accretion disk orbit an event horizon ringed by trapped light, and read the Schwarzschild radius, photon sphere and ISCO for any mass.
Open lab FreeCentripetal Force
What keeps anything moving in a circle. Swing a mass on a string, set the mass, radius and speed, read F = mv²/r live, then cut the string and watch it fly off along the tangent.
Open lab FreeTorque
Why a long spanner beats a short one. Place weights on a balance beam, see each moment τ = m·g·d, and trade mass for distance until the lever sits level.
Open lab FreeHooke's Law
The straight line behind every spring. Hang a mass, watch it stretch by x = mg/k, and read the spring constant straight off the force-versus-extension graph.
Open labWaves & Optics
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.
Open lab FreeDouble-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.
Open lab FreePhotoelectric Effect
The experiment that forced physics to accept the photon. Shine light on a metal, watch electrons fly off above a threshold frequency, and read Planck's constant off the stopping-voltage line.
Open lab FreeBohr Model
The atom that comes in steps. Move an electron between hydrogen's energy levels, watch it emit a photon as it falls, and build the red-cyan-violet Balmer spectrum line by line.
Open lab FreeDoppler Effect
Why a passing siren drops in pitch. A moving source bunches its wavefronts ahead and stretches them behind — push it to Mach 1 and the waves pile into a sonic boom.
Open lab FreeRefraction & Snell's Law
Watch light bend as it crosses a boundary. Change the angle and the two media, read every angle by Snell's law, and push past the critical angle into total internal reflection.
Open lab FreeGeometric Optics: Ray Diagrams
Draw ray diagrams for lenses and mirrors. Trace the principal rays through a convex lens or concave mirror, drag the object, and read the image distance, magnification and type live.
Open lab FreePrism Light Dispersion
Send white light through a triangular prism and watch it fan into a rainbow. Tilt the apex and incidence angles, swap crown glass for flint or water, and read the deviation, dispersion and total internal reflection live.
Open lab FreeQuantum Tunneling
Fire a particle at a wall it cannot climb — and watch part of the wave appear on the other side. Change the energy and barrier and read the exact transmission probability.
Open labElectricity & Circuits
Electric Field Simulator
Drop positive and negative point charges and watch the electric field appear as field lines or vectors. Drag charges to reshape the field and see how it points away from + and into −.
Open lab FreeCharged 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.
Open lab FreeAurora Simulator
How the northern lights form. Solar-wind particles spiral along Earth's magnetic field; the ones in the loss cone reach the atmosphere and light green, red and purple curtains at both poles.
Open lab FreeCoulomb's Law
What makes charges attract or repel — and how hard. Set two charges and their separation and see the force F = kq₁q₂/r², with the inverse-square drop-off as you pull them apart.
Open lab FreeElectromagnetic Induction
Make electricity from motion. Push a magnet through a coil and watch Faraday's law induce a voltage — the galvanometer needle flipping as the magnet passes through.
Open lab FreeCircuit Simulator
Ohm's law you can watch. Wire a battery to three resistors, flip between series and parallel, and read the current, voltage and power as V = I·R re-solves the whole circuit.
Open lab FreeRC & RL Circuits
Circuits that take time. Charge a capacitor or inductor through a resistor and watch the exponential curve, with the time constant τ = RC or L/R and the 63% mark.
Open lab FreeLogic Gates
The building blocks of every computer. Flip binary inputs through AND, OR, NOT, NAND, NOR, XOR and XNOR gates and watch the output and truth table light up.
Open lab FreeVoltage Drop
Every metre of cable loses a little voltage. Set the current, run length, conductor and AWG gauge and see the drop in volts and percent, the load voltage and the power wasted as heat.
Open lab FreeOhm's Law + Power
Enter any two of voltage, current, resistance and power and get the other two, from V = I·R and P = V·I, on a battery-and-resistor circuit whose resistor glows with the power it burns.
Open lab FreeResistor Color Code
Turn the colored stripes on a resistor into a number. Pick 4, 5 or 6 bands and read the resistance, tolerance and range, with a color-coded resistor drawn live.
Open lab FreeLED Resistor
Size the current-limiting resistor for your LEDs from R = (Vs − Vf) / If, with the nearest standard value, a safe power rating and a warning when the supply is too low.
Open lab FreeVoltage Divider
Two resistors turn one voltage into a smaller one: Vout = Vin·R2/(R1+R2). See the tapped output, the loading effect of a connected load, and the current it draws.
Open labFields & Fluids
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.
Open lab FreeParticle Collider Simulator
Smash particles together in your browser. Send an electron and a positron around a particle accelerator, collide them, and read the curving tracks in a detector — crank the energy to 91 GeV and light up a Z⁰ boson.
Open lab FreeIdeal Gas in a Box
Watch PV = nRT emerge from bouncing particles. Change the number of particles, the temperature and the volume, and see the pressure respond while PV/NT stays constant.
Open lab FreeStates of Matter
Heat a box of atoms and watch it melt and boil. A real Lennard-Jones molecular-dynamics sim: cool to a solid crystal, warm to a flowing liquid, heat to a gas, with live temperature and phase.
Open lab FreeCarnot Cycle
The perfect heat engine that sets the efficiency ceiling. Watch a gas trace its PV-diagram loop between hot and cold reservoirs and read η = 1 − T꜀/Tʜ live.
Open lab FreeBuoyancy
Why a ship of steel floats but a nail sinks. Drop a block into a fluid, watch it float or sink by density, and see the buoyant force equal the weight of fluid displaced.
Open lab Free4-Stroke Engine
How a petrol engine turns fire into motion. Watch the piston cycle through intake, compression, power and exhaust, with the Otto-cycle PV diagram and the thermal efficiency that climbs with compression ratio.
Open labEnergy
Wind Turbine
The Betz limit, the power curve, and where the energy actually goes. Spin a turbine against the wind, watch losses stack up, and see how much lands in the battery.
Open lab FreeSolar Panel
Real sun geometry, the Shockley-Queisser limit, and where the energy actually goes. Set panel tilt and latitude, watch losses stack up, and see how much lands in the battery.
Open lab FreeNuclear Energy Lab
The Carnot ceiling, the decay heat that never really switches off, and where the energy actually goes. Run the reactor, trip a shutdown, and watch the cooldown safety margin play out.
Open lab FreeGeothermal Energy Lab
The low-ΔT Carnot ceiling, the waste heat that dominates the balance, and how fast a reservoir can cool. Run the plant across decades and watch the sustainable draw rate emerge.
Open labStorage
Battery Storage Lab
Round-trip efficiency, how fast charging wastes energy as heat, and how depth and heat shorten cycle life. Run a charge-hold-discharge cycle and watch the losses stack up.
Open lab FreePumped Hydro Storage Lab
Round-trip efficiency, friction losses at high flow, and how head and reservoir size set capacity. Pump uphill, hold, then generate back down and watch the losses stack up.
Open lab FreeFlywheel Energy Storage Lab
Round-trip efficiency, its fast bearing-friction and windage self-discharge, and how rotor mass, radius and speed set capacity. Spin up, hold, then discharge and watch the losses stack up.
Open lab FreeHydrogen Energy Storage Lab
Two conversions cut round-trip efficiency, but a sealed tank holds its charge for months. Electrolyze, hold, then run the fuel cell and watch the losses stack up.
Open labPropulsion
Rocket Launch Lab
The rocket equation's Δv ceiling, why it costs exponentially, and how gravity and drag eat into it on the way up. Fly ignition through burnout and watch the losses stack up.
Open lab FreeJet Engine Lab
Overall efficiency splits into thermal times propulsive, why static thrust wastes the second term, and the high-bypass tradeoff that saves fuel. Spool up, accelerate and cruise while the loss bar tracks where the energy goes.
Open lab FreeIon Thruster Lab
Total efficiency splits into electrical times mass utilization times beam divergence, and the thrust-to-power vs specific-impulse tradeoff that swaps fast bursts for huge Δv on a long burn. Throttle up, run the mission and watch the loss slices add up.
Open lab FreePropeller Lab
Efficiency splits into induced times profile times swirl, why static thrust burns power for zero efficiency, and the bigger-disk-vs-tip-Mach tradeoff. Run up, take off and cruise while the loss bar tracks where the power goes.
Open labChaos & Complexity
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.
Open lab FreeBifurcation 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.
Open lab FreeReaction-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.
Open lab FreeConway'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.
Open lab FreeRadioactive Decay
Watch nuclei decay one by one at random, yet trace a perfectly smooth exponential curve. See the half-life law N = N₀·2^(−t/t½) rise out of pure chance.
Open lab