Interactive physics simulations you can run yourself.

Acceleration Lab a = Δv/Δt Change the initial velocity and acceleration and read the acceleration off the slope of a live velocity-time graph. Explore lab » Angular Velocity Free interactive angular velocity simulator: set the spin rate in rpm, slide the marker out from the axis, and watch rad/s, period and tangential speed respond. Explore lab » Distance vs Displacement Lab distance = |displacement| Build a multi-leg journey and compare the total path length with the straight-line displacement. Explore lab » Escape Velocity v_esc = sqrt(2·G·M / r) Set a launch speed as a percentage of escape velocity on four worlds and watch the apogee run away at 100 %. Explore lab » Motion Graphs s = u·t + ½·a·t² Set the initial velocity and acceleration and watch the position-time and velocity-time graphs draw themselves. Explore lab » SUVAT Equations Lab v = u + a·t Change the initial velocity, acceleration and time and watch displacement and final velocity respond through v = u + a·t. Explore lab » Tangential Acceleration ac = v²/r Brake into a bend and watch the acceleration lean off the centre, drawn against the grip budget. Explore lab » Terminal Velocity Lab vt = sqrt(2mg/ρACd) Change the mass, cross-sectional area and drag coefficient and watch drag rise until it balances weight. Explore lab » Vector Addition R = A + B Change two vectors\ Explore lab » Velocity vs Speed Lab v = d/t An object circles at constant speed while its velocity keeps turning — speed is a scalar, velocity a vector. Explore lab »

Absolute Zero T(K) = T(°C) + 273.15 Set a temperature from 600 K down to 0 K, pick a gas, and watch the molecules slow and the gas volume shrink to zero. Explore lab » Alpha Decay A - 4, Z - 2 Alpha decay simulator: a free simulation of twelve real alpha emitters. Pick one and read the daughter, the decay energy, the alpha's share and the half-life. Explore lab » Angular Momentum L = Iω Angular momentum simulator: a free simulation where you move two masses in or out on a turntable and read the spin rate, angular momentum and rotational energy. Explore lab » Antimatter Annihilation E = 2mc² Free interactive antimatter simulator: set the antimatter mass, pick electron-positron or proton-antiproton, and see the energy released by E = 2 m c squared. Explore lab » Atomic Structure A = Z + N Atom simulation: build any atom or ion from hydrogen to calcium with proton, neutron and electron sliders and see its atomic structure, charge and isotopes. Explore lab » Avogadro's Law V1/n1 = V2/n2 Avogadro's law simulator: a free simulation where you set the amount of gas in two cylinders and read back the volume, the molar volume and the volume ratio. Explore lab » Banked Curve tanθ = v²/rg Free interactive banked curve simulator: move the angle, radius, speed and friction sliders and watch tanθ = v²/rg set the ideal no-friction speed live. Explore lab » Blackbody Radiation M_lam Drag the temperature, shade any wavelength band and read what share of the radiated power lands in it. Explore lab » Capacitance C = Q/V Drag plate area, gap and dielectric to see capacitance, charge and stored energy update live from C = Q/V. No sign-up. Explore lab » Carbon Dating t = (t½ / ln 2) · ln(N0 / N) Carbon dating simulator: a free radiocarbon simulation where you set the measured carbon-14 level and read the radiocarbon age, its error bar and half-lives. Explore lab » Carnot Efficiency eta = 1 - Tc ÷ Th Drag the hot and cold reservoir temperatures and watch work and waste heat split live, from eta = 1 - Tc/Th. Explore lab » Center of Gravity θc = arctan((b/2)/h) Change the base width, centre-of-gravity height and tilt and watch an object stay stable or topple. Explore lab » Center of Mass xcm = Sum(m*x) / Sum(m) Slide three masses and watch the balance point move as x_cm = Sum(m*x)/Sum(m) updates live. Test it in your browser. Explore lab » Centripetal Force Lab F = mv²/r Change the speed and radius and watch the centripetal force, acceleration and period respond through F = mv²/r. Explore lab » Circular Motion a = v²/r Drag speed, radius and mass to watch a = v2/r respond live, and cut the string to see the tangent escape. Explore lab » Concave & Convex Mirror 1/f = 1/v + 1/u Move the object and flip the curvature to see real and virtual images form through 1/f = 1/v + 1/u. Explore lab » Decay Chain A1 = λ1N1 Decay chain simulator: a free simulation of a parent, its radioactive daughter and a stable end. Two half-life sliders set the shape, and a clock runs it. Explore lab » Decibel and Sound Intensity L = 10·log10(I / I0) Drag the power, distance and source-count sliders and watch the sound level update live using L = 10 log10(I/I0). Explore lab » Diffraction Grating d·sinθ = nλ Free interactive diffraction simulator: drag the wavelength, line density and slit count to watch the bright orders move and see d sin θ = nλ in action. Explore lab » Drag Force F = ½ρv²CdA Change speed, frontal area, drag coefficient and density and watch the drag and power readouts follow F = half rho v squared CdA. Explore lab » E=mc² E = mc² Free interactive E=mc² simulator: set a mass and how much of it converts, then watch the energy released in joules and tonnes of TNT. See why one gram equals a bomb. Explore lab » Elastic Potential Energy E = ½·k·x² Change the spring constant and displacement and watch the stored energy respond through E = ½·k·x². Explore lab » Electrical Resistance R = ρL/A Free interactive resistance simulator: drag length, area and temperature, switch metals, and watch R = ρL/A and the current update live. Explore lab » Energy Conservation PE = m·g·h Change the release height and watch potential and kinetic energy trade off in a frictionless valley. Explore lab » Equilibrium & Torque — Balance Beam Lab m1·d1 = m2·d2 Change the masses and their distances on a balance beam and watch the principle of moments balance the beam. Explore lab » Force & Acceleration F_net = m·a Free interactive Newton\ Explore lab » Fourier's Law Q/t = k · A · dT ÷ d Free interactive Fourier's law simulator: drag conductivity, area, thickness and temperature difference and watch the heat-loss rate in watts update live. Explore lab » Free Body Diagram N = mg cosθ − F sinφ Free interactive free body diagram simulator: drag the angle, mass, applied force and friction sliders and watch every force arrow resize live as N = mg cosθ. Explore lab » Free Fall Free interactive free fall simulator: drag the height and gravity sliders, drop two different masses, and watch fall time and impact speed update live. Explore lab » Friction on an Incline m·g·sin(θ) Change the ramp angle, the coefficients of friction and the mass, and watch static friction build. Explore lab » Gamma Ray Shielding μ Free interactive gamma ray simulator: set photon energy, shield material and thickness, and watch transmitted intensity follow I = I0 exp(-mu x) live. Explore lab » Hooke's Law Lab F = k·x Free interactive Hooke\ Explore lab » Inclined Plane mg sinθ Drag the angle, mass and friction sliders and watch mg sinθ, mg cosθ, N and the acceleration update live. Explore lab » Jerk in Physics j = da/dt Set the jerk and the clock, and read off the displacement a constant-acceleration equation cannot account for. Explore lab » Kepler's Laws T² = 4π²a³/(GM) Kepler's laws simulator: an orbit simulation where you set the semi-major axis, eccentricity and star mass, then watch equal areas, speeds and the period. Explore lab » Kirchhoff's Law det = R1·R2 + R1·R3 + R2·R3 Drag two EMFs and three resistances and watch the branch currents flip sign live, solving I1 + I2 = I3 as you go. Explore lab » Lenz's Law ε = -N dΦ/dt Lenz's law simulator: a free simulation where you set where the magnet is and which way it moves, then read the direction of the induced current and the force. Explore lab » Mechanical Advantage IMA = effort arm / load arm Try a lever, pulley or ramp and watch how each trades force for distance. Explore lab » Moment of Inertia Change mass, radius, shape and axis position, and watch I = k m r squared update live with the readouts. Explore lab » Momentum & Collisions Lab p = m·v Set the masses, velocities and restitution and watch momentum stay constant through every collision. Explore lab » Momentum & Impulse Lab J = F·Δt = Δp Set two masses and velocities and watch impulse, momentum and force play out through J = F·Δt = Δp. Explore lab » Newton's Second Law a = F/m Free interactive Newton\ Explore lab » Physics Constants Switch between g, c, h, G, R, k_e and sound, move one slider, and watch each constant do its actual job. Explore lab » Physics Formula Rearranger A = B × C Pick a relationship, choose the unknown, move the sliders, and watch the rearranged equation and unit check. Explore lab » Physics Symbols λ Free interactive physics symbols simulator: pick a symbol, move one slider, and watch the quantity it names change live with its SI unit and its formula. Explore lab » Polarization & Malus's Law I = I0·cos²θ Free interactive polarization simulator: rotate the analyzer and watch transmitted intensity follow Malus\ Explore lab » Potential Difference V = W/Q Free interactive potential difference simulator: drag the supply, resistance and charge sliders to see how volts split across a series circuit and why V = W/Q. Explore lab » Power Lab — Force × Velocity P = F·v Change the force and velocity and watch the power respond through P = F·v, in watts and horsepower. Explore lab » Projectile Motion R = v²·sin(2θ) / g Change the launch angle, initial velocity and gravity and watch the range, height and flight time respond. Explore lab » Quarks Build protons, neutrons and mesons from up, down and strange quarks and watch the fractional charges add to a whole number. Explore lab » RC Time Constant τ = R · C Drag R, C and supply voltage to watch a capacitor charge or discharge, and see why tau = RC alone sets the 63% timing. Explore lab » Refractive Index n = c/v Free interactive refractive index simulator: slide n from 1.00 to 2.50, watch light slow and its wavelength shrink, and read v = c/n live for any material. Explore lab » Reynolds Number Re = ρ·v·D/μ Pick water, air, glycerine or oil, set the speed and pipe bore, and watch a dye streak go from laminar to turbulent. Explore lab » Right-Hand Rule Trainer no direction (the force is zero) Pick any two directions and the trainer draws and names the third, for a moving charge, a wire or a coil. Explore lab » SI Units & Prefixes Free interactive SI units simulator: drag the exponent slider from quetta to quecto and watch one value get renamed by all 24 metric prefixes in real time. Explore lab » Simple Harmonic Motion Lab T = 2π·sqrt(m/k) Change the mass, spring constant and amplitude and watch the period, frequency and energy respond. Explore lab » Simple Pendulum T = 2π·sqrt(L/g) Change the length, gravity and starting angle and watch the period respond. Explore lab » Spring Constant k = F/x Free interactive spring constant simulator: hang masses, watch the spring stretch, and read k from the live force-extension graph. Uses k = F/x in N/m. Explore lab » Stefan-Boltzmann Law P = σεAT^4 Drag temperature, emissivity and area to see radiated power jump with the fourth power of temperature. Explore lab » Superconductor Critical Surface Bc(T) = Bc0[1 − (T/Tc)²] Drag the temperature, the field and the current, and watch a lead wire cross its critical surface and quench. Explore lab » Tension Force Lab T = m(g + a) Change the mass and a lift\ Explore lab » Time Dilation Free interactive time dilation simulator: set the speed and proper time, then watch the Lorentz factor climb as the moving clock falls behind a rest clock. Explore lab » Torque τ = r·F·sinθ Change the applied force, distance and angle and watch the torque and lever arm respond through τ = r·F·sinθ. Explore lab » Ultraviolet Radiation E = hc / lambda Drag one wavelength from 100 to 400 nm and watch the photon energy, the UV band and a threshold move. Explore lab » Unit Conversions Set any value, pick from and to units across force, energy, pressure, length and temperature, and see the factor. Explore lab » Universal Gravitation F = G·m1·m2 / r² Free interactive gravitation simulator: drag two masses apart and watch the force fall as one over r squared. Live force and field readouts, F = Gm1m2/r2. Explore lab » Watts to Amps I = P / (V × PF) Watts to amps simulator: set the load power, supply voltage, DC, single- or three-phase AC and power factor, and watch an ammeter show the current drawn. Explore lab » Weight on Other Planets W = m × g Free weight on other planets simulator: set a mass, pick the Moon, Mars, Earth or Jupiter, and watch W = mg change the scale reading live. Explore lab » Weight vs Mass W = m·g Carry a mass to the Moon, Mars, Earth and Jupiter and watch its weight change while its mass stays fixed. Explore lab » Work Done Lab W = F·d·cosθ Change the force, angle and displacement and watch the work respond through W = F·d·cosθ. Explore lab » Work-Energy Theorem Wnet = ½mv2² − ½mv1² Work energy theorem simulator: a free simulation where you push a block against friction and read the net work, the change in kinetic energy and the speed. Explore lab »

Atmospheric Pressure P = P0·(1 - L·h/T0)^5.256 Set any altitude to 20 km and a sea-level pressure and see a mercury barometer track the standard atmosphere. Explore lab » Bernoulli's Principle v2 = v1·(d1/d2)² Free interactive Bernoulli\ Explore lab » Buoyancy Lab W = ρ_object · V · g Change the object density, volume and fluid density and watch it float or sink, with the buoyant force. Explore lab » Density & Floatation Lab ρ = m/V Change an object\ Explore lab » Pascal's Law F2 = F1·(d2/d1)² Free interactive Pascal\ Explore lab » Pressure P = F/A Change the force, contact area and depth and watch contact pressure P = F/A and fluid pressure P = ρgh respond. Explore lab » Surface Tension, Beads and Capillary Rise γ = F / L Drag the tension, contact angle and tube radius sliders to watch a drop bead up and water climb a capillary. Explore lab » Viscosity and Shear Stress Drag the plate, change the gap and the fluid, and watch shear stress equal viscosity times shear rate in real time. Explore lab »

Boyle's Law P1V1 = P2V2 Free interactive Boyle\ Explore lab » Charles's Law V1/T1 = V2/T2 Free interactive Charles\ Explore lab » Combined Gas Law P1V1/T1 = P2V2/T2 Combined gas law simulator: a free simulation of one sealed gas in two states. Five sliders set the before and the after, and the volume after is worked out. Explore lab » Entropy S = Q / T Slide the heat and both reservoir temperatures to watch the entropy ledger, and see S = k ln W count microstates live. Explore lab » First Law of Thermodynamics ΔU = Q − W Adjust heat and process type, watch ΔU = Q - W update live. Explore isothermal to adiabatic paths. Explore lab » Gay-Lussac's Law P1/T1 = P2/T2 Gay-Lussac's law simulator: a constant-volume gas simulation where you set the sealed pressure, change the temperature and read absolute and gauge pressure. Explore lab » Heat Transfer Q/t = kAΔT/d Change the temperatures, conductivity, thickness and emissivity and compare conduction, convection and radiation. Explore lab » Heat vs Temperature Q = m·c·ΔT Heat two water beakers of different masses and see why heat is energy and temperature is how hot it is. Explore lab » Ideal Gas Law PV = nRT Change the moles, temperature and volume and watch the pressure respond through PV = nRT. Explore lab » Isothermal Process P = nRT/V Drag two volumes on a PV diagram, read the work as the shaded area, and compare it with a free expansion. Explore lab » Latent Heat Q = m·L Heat ice with a chosen power and watch the heating curve flatten at melting and boiling. Explore lab » Laws of Thermodynamics — Heat-Engine Lab η = 1 - Tc/Th Run a heat engine between hot and cold reservoirs and watch the first law and the Carnot efficiency. Explore lab » Specific Heat Q = m·c·ΔT Add the same energy to equal masses of water, aluminium and iron and watch them reach different temperatures. Explore lab » Thermal Diffusivity t = 0.4911 L²/α Thermal diffusivity simulator: a free interactive lab that draws the temperature through a warming slab and reads off the time it takes to reach steady state. Explore lab » Thermal Expansion ΔL = α·L0·ΔT Pick a metal, change the temperature and original length, and watch a rod stretch through ΔL = α·L0·ΔT. Explore lab »

Concave vs Convex Lens — Ray Diagram Lab 1/v = 1/f + 1/u Change lens type, focal length and object distance and watch real and virtual images form. Explore lab » De Broglie Wavelength lambda = h / (m · v) Drag the mass and speed sliders to see lambda = h/mv collapse from nanometres to nothing at all. Explore lab » Dispersion of Light — Interactive Prism Lab sin i = n sin r Free interactive dispersion of light simulator: set the prism angle, index and Abbe number to fan white light into a spectrum and read every deviation angle. Explore lab » Doppler Effect Lab f_ahead = f·c/(c − vs) Change the source speed and emitted frequency and watch the frequency ahead rise and the frequency behind fall. Explore lab » Electromagnetic Spectrum Explorer c = fλ Sweep from radio waves to gamma rays and watch wavelength, frequency and photon energy from c = fλ. Explore lab » Lens Equation 1/f = 1/do + 1/di Drag the object distance and focal length sliders to see image distance, magnification and image type update live. Explore lab » Reflection & Refraction Lab n1·sinθ1 = n2·sinθ2 Free interactive Snell\ Explore lab » Speed of Light Lab c = 299,792,458 m/s Pick a destination and see the light-travel time from distance/c, why we see the past, and how n = c/v slows light. Explore lab » Speed of Sound v = sqrt(γRT/M) Drag temperature, switch gas and add humidity to watch the pulse race, with live speed and Mach 1 readouts. Explore lab » Transverse vs Longitudinal Waves Lab v = f·λ Free interactive transverse and longitudinal waves simulator. Compare perpendicular and parallel particle motion, crests, compressions and v = f·λ. Explore lab » Wave Generator Open simulation » Wave Speed in Two Media Pick two media, set the frequency, and watch the wavelength change while v = f x lambda holds on both sides. Explore lab » Wave-Particle Duality lambda = h / p Fire single electrons at a double slit, see each arrive as one dot, then watch the dots build fringes. Explore lab »

AC vs DC Current Vrms = V0/sqrt(2) Slide peak voltage and frequency to see the sine wave, the flat DC line and the RMS value that makes them equal. Explore lab » Coulomb’s Law Lab F = k·q1q2/r² Free interactive Coulomb\ Explore lab » Eddy Currents d² Cut a copper block into up to 40 insulated laminations and watch the loss fall from 1.300 kW to 1.530 W. Explore lab » Electric Current I = Q/t I = Q/t Free interactive electric current simulator: slide the charge and time to see current I = Q/t and the electron count update. Explore lab » Electric Field of a Point Charge E = kQ/r² Change the charge and probe distance and watch the field of a point charge respond through E = kQ/r². Explore lab » Electric Potential Ex = -dV/dx Slide a probe between two point charges and see where V is zero while the field is not, and the reverse. Explore lab » Electricity Cost E = P × t ÷ 1000 Drag wattage, daily hours and your tariff to watch kWh and running cost update live. Cost = kWh times rate. Explore lab » Electromagnet B = μrμ0nI Free interactive electromagnet simulator: change turns, coil length, current and core, and watch the field follow B = permeability x turns per metre x current. Explore lab » Electromagnetic Induction — Faraday's Law Lab ε = -N ΔΦ/Δt Change the coil turns, field, area and drive frequency and watch Faraday\ Explore lab » Inside a Solenoid B = μ0nI Drag turns, length and current to see the magnetic field inside a coil change live, and watch B = mu0nI in action. Explore lab » Magnetic Field & the Lorentz Force F = qvB Change the charge, speed and field and watch a moving charge curve through F = qvB into a circle of radius r. Explore lab » Magnetic Flux 0.200 T Hold the flux density and the loop area still, tilt the loop, and watch the flux fall to zero and reverse. Explore lab » Ohm's Law Lab V = I·R Change the voltage and resistance and watch the current respond through V = I·R, with the ohmic physics explained. Explore lab » Series and Parallel Circuits Lab R_total = R1 + R2 + R3 Change the battery voltage and three resistors, flip between series and parallel. Explore lab »

Beta Decay & the Beta Spectrum Free interactive beta decay simulator: choose a real isotope, fire beta-minus, beta-plus or electron capture, and watch the true beta spectrum build up. Explore lab » Bohr Model of the Atom Set the start and end levels, fire the jump, and read the photon energy and wavelength live from E = -13.6/n² eV. Explore lab » Fission vs Fusion E = Δm·c² Slide along the binding-energy curve past iron-56 and see why fusion and fission both release energy. Explore lab » Half-Life & Radioactive Decay N = N0(1/2)^(t/t½) Change the half-life and the number of atoms and watch radioactive decay follow N = N0(1/2)^(t/t½). Explore lab » Neutrino Oscillation Interactive neutrino oscillation simulator: drag baseline, energy, mass splitting and mixing angle and watch flavour change as P = sin2(2t)sin2(1.27 dm2 L/E). Explore lab » Nuclear Reactor Control ρ = (k − 1) / k Move the control rods and fuel enrichment to set k, and watch reactor period and power respond in real time. Explore lab » Photoelectric Effect Kmax = hc/λ - φ Change the wavelength, intensity and work function and watch emission, stopping voltage and Kmax respond. Explore lab » Special Relativity Lab β = v/c Adjust the speed β = v/c and watch the Lorentz factor γ stretch time and contract length. Explore lab » The Schrodinger Equation: Particle in a Box E = n²h² / 8mL² Drag the box width and the quantum number and watch the energy levels climb as n squared over L squared, live. Explore lab » The Uncertainty Principle Δx · Δp >= h-bar/2 Slide the position spread and watch the momentum spread widen in step, with the product pinned at h-bar over 2. Explore lab »