Real numerical simulations you can nudge and watch respond — a spring-mass system across every damping regime, pendulums from predictable to chaotic, ballistics that carry their own drag, and orbits worked from Newton upwards. Beverage Cooling solves the same heat equation as the Steak Timer and the Egg Timer: same physics, different object. A can in a fridge, a steak in an oven and an egg in boiling water differ only in their boundary condition and what they are made of.
A second-order system across all four damping regimes — set the mass, spring and damping, and watch the step response ring, settle, or crawl.
Snell's law, critical angle and Fresnel reflection with a live ray diagram, plus single-slit, double-slit, grating and Airy-disc patterns drawn out.
The same Lagrangian mechanics, one, two, or three links deep — from a clean predictable swing to full chaotic motion.
A block on a slope, simulated with real friction — set the angle and coefficients and watch whether it holds, slides, or slides back.
A real 2D transient heat-transfer simulation — watch a can or bottle actually cool, with live convection and radiation physics.
The classic no-drag trajectory, plus a real 3D drag + Magnus-lift golf simulator — clubs, wind, world gravity, bounce and roll.
Race two falling objects with real drag physics — recreate Apollo 15's hammer-and-feather drop on the Moon.
Enter any three of s, u, v, a and t and get the other two, with the equation used and the working shown.
Built from one fact: everybody measures light at the same speed. Watch a light clock slow down, see why “now” is not universal, and find the 38 microseconds a day that satellite navigation depends on.
Every planet in 3D, drawn from its real orbital elements — at true scale, where they all but vanish, and compressed, where you can see them. Size against size, and a head-to-head on ten measures.
Kepler's laws and the vis-viva equation, with a live animated orbit — try the ISS, geostationary, or a Molniya orbit.
Stage a rocket, watch it launch, and see if it can actually reach orbit — real vehicle presets included.
Multi-ball collisions and Newton's Cradle, from perfectly elastic to perfectly inelastic — up to 10 balls.