Pendulum Lab Simulator
Explore period, gravity and energy with a swinging pendulum.
Drag a bob sideways and let go. Change the length, mass, gravity and friction of the two pendulums and compare their periods. Use the ruler, protractor, timer and energy graph like in a real lab.
About the Pendulum Lab Simulator
Free online pendulum simulation. Adjust length, mass, gravity, starting angle and damping, and watch the period and kinetic and potential energy update in real time. Built for physics, the pendulum lab simulator runs instantly in your browser: change a setting or drag an object and the result updates at once, so you learn by trying things out rather than only reading about them.
Explore period, gravity and energy with a swinging pendulum. Use it to explore physics ideas at your own pace, then check what you found against the key ideas further down this page.
How to use the Pendulum Lab Simulator
- Use the controls to change Pendulum 1 length, Pendulum 1 mass, Pendulum 2 length, Pendulum 2 mass, Gravity, and more. The simulation reacts instantly.
- Pick an option such as Moon, Earth, Jupiter, Planet X to switch modes or load an example.
- Press "Same starting angle", "Reset" to start, reset or change what is happening.
- Where you see a glowing handle, object, weight or atom, drag it with your mouse or finger. Everything responds in real time.
- Watch the readouts and graphs update as you experiment, and compare what you see with the key ideas below.
Things to try
- Change the length and read the period.
- Drag the bob to 80° and compare the measured and formula periods.
- Turn damping up and watch the energy fade.
- Move to the Moon by lowering gravity.
Key ideas you can learn
- For small angles the period is T = 2π√(L/g). It does not depend on mass.
- Kinetic and potential energy trade off while the total stays constant (without damping).
- Longer pendulums swing slower; stronger gravity makes them swing faster.
Where this is used in the real world
Pendulums keep time in clocks, measure gravity in geology, and describe how playground swings, wrecking balls and bridge cables sway. Seismometers and metronomes use the same maths.
Who is this simulation for?
Physics students in middle school, high school and first-year university, teachers who want a quick demonstration for the projector, and anyone revising for exams. It works well for flipped classrooms because students can explore before the lesson.
For teachers: project it on the board, let students predict what will happen, then run it together. For students: change one thing at a time and write down what changes.
Frequently asked questions
Does the mass of a pendulum change its period?
No. In the ideal pendulum the period depends only on length and gravity. Try changing the mass slider and watch the period stay the same.
Why does the period change at large angles?
The T = 2π√(L/g) formula assumes small angles. At large angles the real period is longer, and this simulator uses the full pendulum equation so you can see it.
Is the Pendulum Lab Simulator free to use?
Yes. It is completely free, with no signup, no download and no ads inside the simulation. It runs in your web browser.
Does the Pendulum Lab Simulator work on a phone or tablet?
Yes. It uses touch as well as the mouse, so you can drag objects with your finger. A larger screen makes the controls easier to see.