Free interactive simulations
Move a slider, drag an object and watch the science respond instantly. Every simulation runs in your browser.
Physics
Projectile Motion
Fire a cannon. Explore angle, speed, gravity and air resistance.
Pendulum Lab
Swing pendulums, measure the period, and watch kinetic and potential energy trade places.
Masses and Springs
Hang masses from springs. Hooke's law, oscillation period and energy.
Wave Interference
Ripple tank with two sources or a double slit: constructive and destructive interference.
Gravity and Orbits
N-body gravity sandbox: planets, moons, binary stars and the figure-eight orbit.
Collision Lab
Balls collide in 1D or 2D. Momentum is conserved; kinetic energy depends on elasticity.
Energy Skate Park
Build a track and watch a skater trade potential energy for kinetic energy.
Charges and Fields
Arrange point charges and see the electric field, potential map and field lines.
Photoelectric Effect
Shine light on a metal and knock out electrons. See why colour, not brightness, decides whether it works.
Hydrogen Atom and Spectra
Kick the electron up the energy levels and watch it fall back, giving out light of exact colours.
Radioactive Decay and Half-Life
Watch unstable nuclei decay one by one at random, and see the half-life appear from the chaos.
Blackbody Radiation
Heat an object from body temperature to a blue star and watch its colour and spectrum change.
Chemistry
Gas Properties
Pump particles into a box, heat it and change its volume. Ideal gas law and speed distribution.
States of Matter
Heat and cool atoms bound by intermolecular forces: watch solid, liquid and gas form.
pH Scale
Test everyday liquids, dilute them with water, and see how H₃O⁺ and OH⁻ change.
Build an Atom
Add protons, neutrons and electrons. Find the element, its charge and mass number, and whether it is stable.
Balancing Chemical Equations
Adjust the coefficients until every atom is conserved. Twelve levels.
Beer's Law Lab
Shine light through a coloured solution: absorbance depends on concentration, path length and wavelength.
Molecule Shapes
Type any molecule or ion, or build one in 3D. VSEPR predicts the shape and bond angles.
Biology
Natural Selection
Bunnies with mutations face wolves and changing environments. Watch allele frequencies evolve.
Diffusion & Membranes
Remove the divider or open membrane channels and watch particles spread down their concentration gradient.
Predator–Prey Dynamics
Lotka–Volterra model: rabbit and fox populations rise and fall in linked cycles.
Math
Calculus Grapher
Type any function and see its derivative, integral and a draggable tangent line.
Fourier: Making Waves
Add sine harmonics to build square, sawtooth and triangle waves, and hear them.
Vector Addition
Type or drag vectors, see their components, and build the resultant tip to tail.
Plinko Probability
Drop balls through a Galton board and watch the binomial distribution emerge.
Trig Tour
Drag a point around the unit circle and trace sin, cos and tan.