Pendulum Lab: free physics simulation
Swing pendulums, measure the period, and watch kinetic and potential energy trade places.
▶ Open the simulationFree, no sign-up. Works on phones, tablets and laptops.
The science
A simple pendulum swings with a period that depends only on its length and the strength of gravity, not on the mass of the bob (for small swings). As it swings, energy changes back and forth between gravitational potential energy at the ends and kinetic energy at the bottom.
Period T = 2π √(L / g)
Things to try
- Make the string four times longer and check the period doubles.
- Change the mass and confirm the period stays the same.
- Lower gravity (as on the Moon) and time the swings again.
Topics covered
oscillation period simple harmonic gravity energy
How to use it
Open the simulation, then change the experiment live with the sliders, checkboxes and buttons in the side panel. Drag objects on screen where it makes sense, and use Pause, Step, Speed and Reset in the bottom bar to study every moment.
Frequently asked questions
What does the Pendulum Lab simulation show?
A simple pendulum swings with a period that depends only on its length and the strength of gravity, not on the mass of the bob (for small swings). As it swings, energy changes back and forth between gravitational potential energy at the ends and kinetic energy at the bottom.
What is the key equation?
Period T = 2π √(L / g)
Is the Pendulum Lab simulation free?
Yes. It runs free in any web browser on phones, tablets and laptops, with no sign-up or download.
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