Physics simulations

Spin a platform up, then pull two hand-held masses in toward the axis and watch the spin rate jump — angular momentum stays fixed the whole time, so pulling the masses in tighter is the only thing driving the speed-up.

Hang two masses from a string over a pulley — adjust each mass, gravity, the pulley's own mass, and rope/pulley friction to see which side descends, how their tensions differ, and watch the balanced case where equal masses simply hang still.

Heat an object toward a chosen target temperature and watch it glow the colour a real blackbody emits — deep red to blue-white — while its radiated power rises steeply with temperature.

Fire a charged particle into a uniform magnetic field (a closed cyclotron circle), add a uniform electric field (a bending parabola), or combine both to see the guiding center drift sideways — adjust charge sign, mass, speed, and both fields.

Send two disks toward each other with a chosen impact parameter — adjust their masses, starting speeds, and how off-center the hit is to see a head-on collision exchange velocities and a glancing one deflect both disks sideways, momentum and kinetic energy conserved exactly.

Fire an X-ray or gamma photon at an electron and watch it bounce off with less energy — the wavelength shift depends only on the angle, which is the evidence that light comes in particles.

Fire a charge into a uniform magnetic field, perpendicular to its velocity — adjust the entry speed, field strength, and charge-to-mass ratio to see the radius and period of the resulting circular orbit.

Fly a sound source past a fixed observer — adjust its speed, true pitch, the speed of sound, and how close it passes to hear (and see, in the compressed and stretched wavefronts) the classic pitch glide, and watch a Mach cone form once it goes supersonic.

Hinge a second rod off a swinging pendulum's bob and release both from a large starting angle — watch a genuinely chaotic system where a fraction-of-a-degree difference in the start sends it on a completely different path.

Shine coherent light through two narrow slits and watch the exact bright/dark fringe pattern form on a screen — adjust wavelength, slit separation, slit width, and screen distance to see the fringes tighten, widen, and even lose whole orders to the single-slit diffraction envelope.

Push a damped mass on a spring with a sinusoidal driving force — sweep the driving frequency through the natural frequency and watch the transient build into a steady-state oscillation, tracing out the resonance curve as you go.

Slide a bar magnet through a coil — adjust its speed, the coil's turns, and the magnet's strength to see the induced EMF rise, peak, flip sign as the magnet passes through, and fade as it recedes.

Move a spacecraft from a low orbit to a higher one with two engine burns — see the half-ellipse it coasts along, read both speed changes, and find out why the cheap route is also the slow one.

Live interactive gas cylinder — set the amount of gas, then drag temperature and applied pressure and watch the piston respond in real time as PV=nRT holds exactly.

Watch a planet trace an exact elliptical orbit with the star at one focus, its equal-time sectors shaded to show equal-area sweeps, and a second comparison planet whose period and semi-major axis satisfy the same T^2/a^3 ratio.

Drive a series RLC circuit with an AC source — sweep the drive frequency through the resonant frequency and watch the steady-state current amplitude peak, with the peak's sharpness controlled by the circuit's resistance.

Pick a real gas and sweep its temperature, and watch the curve of how many molecules move at each speed shift, broaden, and flatten — track the shaded fraction moving faster than a chosen speed threshold as the temperature climbs.

Load a sample of some isotope — adjust the isotope, purity, fuel amount, moderator, and cooling/control rods to see the chain reaction fizzle out, self-sustain, or run away, generation by generation.

Shine light of a chosen frequency onto a metal plate — adjust the frequency and the metal's work function to see whether an electron is ejected at all, and at what speed, exactly as Einstein's photon picture predicts.

Push a thick or thin liquid through a narrow pipe and watch the flow profile form — the fluid at the wall barely moves, the centre races, and halving the radius cuts the flow to a sixteenth.

Charge or discharge a capacitor through a resistor — adjust the source voltage, resistance, and capacitance to see the exponential voltage/current curves and the circuit's time constant.

Choose your launch bearing, injection speed, flight-path angle, and lead the Moon's own motion — simulate a real Earth-Moon transfer and see if you reach the Moon's sphere of influence. Reaching it refunds your run.

Release a hoop, a solid disk, and a solid sphere from rest together — each on its own ramp curve (straight incline, brachistochrone, exponential decay, circular arc, or parabola) — and see how both the SHAPE (moment of inertia) and the PATH decide who reaches the bottom first.

Spin up a solid disc, a hoop, and a solid sphere — all sharing the same mass and radius — under the same applied torque, and watch them visibly pull apart purely because of how each one's mass is spread out from the axle.

Fire a beam of alpha particles at a single heavy nucleus — adjust the alpha energy, target atomic number, particle count, and impact-parameter spread to watch Coulomb repulsion alone deflect each trajectory, most only slightly and a rare few sharply back the way they came.

Pluck a string fixed at both ends into a chosen harmonic — adjust its length, tension, and mass per unit length to see how fast, and in how many nodes and antinodes, it vibrates.

Place an object in front of a converging or diverging lens — watch the three principal rays trace out where the image forms, and see whether it's real or virtual, upright or inverted, magnified or reduced.

Put a planet next to a moon or a star and see how gravity pulls the near side harder than the far side — the stretch that raises two tides a day, locks the Moon's face to us, and can tear a moon apart if it strays too close.