How realistic are the numbers?

The physics simulations step the standard equations forward in small time steps, so values closely match the formulas shown. Gas laws and Reaction rates are particle models: pressure and rate are counted from collisions on screen, so they wobble around the ideal value.

Do I need to install anything?

No. Everything runs in your browser on a laptop, tablet or phone, and nothing moves until you press Start.

Are my settings saved?

Slider settings reset when you reload. Your points and your best projectile distance are kept in this browser, and a free Brainlag account syncs them across devices.

Physics and Chemistry Simulations

21 interactive physics and chemistry simulations from GCSE to university, with live graphs, readouts and a prediction challenge.

GCSE

Forces & acceleration

Push harder than friction

Forces on a slope

Will it slide, or stay put?

Momentum and collisions

Bounce, crunch or stick together?

Mass on a spring

Stretch it, let go, watch it bounce

Waves on a string

Add two waves, find the nodes

Refraction and Snell's law

Bend light, then trap it

Lenses and ray diagrams

Where does the image land?

Series & parallel circuits

Series or parallel: which wins?

Radioactive decay

Which nucleus goes next?

Gas laws

Squeeze it, heat it, feel the pressure

Reaction rates

Make A and B react faster

A-Level

Projectile motion

Which angle flies furthest?

Pendulum

What really sets the swing?

Orbits and Kepler's laws

Launch a planet. Will it come back?

Capacitor charging and discharging

How long until it's half full?

Electric fields and equipotentials

Where does the field cancel out?

Double slit and diffraction grating

Two slits, a row of bright lines

Photoelectric effect

Why can't red light do it?

University

Resonance: the driven, damped oscillator

Push at the right rhythm

Particle in a box and tunnelling

Why can't the electron sit still?

Spacetime diagram: special relativity

Whose clock is running slow?

More simulations: Maths Simulations, PhET, Falstad

How to use it

Pick a level (GCSE, A-Level or University), then a simulation: each picture shows what it models.
Set the sliders, such as launch angle, string length, spring constant, voltage, temperature or volume. The readouts update as you move them.
Press Start (Launch on projectile motion) to run it, Pause to freeze it and Reset to begin again.
Watch the live graph, such as height against time, alongside the readouts table.
Pick a playback speed (0.25x to 4x) and open Advanced for more: launch height, gravity on other planets, air resistance and wind for projectiles, and extra options in every other sim.

TipWrite down your prediction before you press Start. The Challenge works best when you commit to an answer first and then test it.

Also useful

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About this tool

Physics and Chemistry Simulations is a free virtual lab with 21 interactive simulations, grouped by level. GCSE: forces, slopes, momentum, springs, waves, refraction, lenses, circuits, radioactive decay, gas laws and reaction rates. A-Level: projectiles, pendulums, orbits, capacitors, electric fields, the double slit and the photoelectric effect. University: resonance, the particle in a box and spacetime diagrams. Each one has sliders, live readouts with units, the key equation and a prediction challenge, and every result is checked against the textbook formula.

Tips

Change one slider at a time and keep the rest fixed. That makes it a fair test, just as you would plan a practical.
Check the equation against the readouts. On the pendulum, compare the measured period with the small-angle value at a small and a large start angle.
In Reaction rates, new amounts of A and B take effect when you press Reset, so reset after changing them.

FAQ

How realistic are the numbers?: The physics simulations step the standard equations forward in small time steps, so values closely match the formulas shown. Gas laws and Reaction rates are particle models: pressure and rate are counted from collisions on screen, so they wobble around the ideal value.
Do I need to install anything?: No. Everything runs in your browser on a laptop, tablet or phone, and nothing moves until you press Start.
Are my settings saved?: Slider settings reset when you reload. Your points and your best projectile distance are kept in this browser, and a free Brainlag account syncs them across devices.