Masses and Springs: Bounce Lab
Hang masses on two springs, compare stiffness, gravity and damping, and measure the bounce period.
Drag a mass onto the hook of a spring and let go. It bounces. Compare stiff and soft springs, heavy and light masses, and change gravity or damping.
About the Masses and Springs: Bounce Lab
Free masses and springs: bounce lab. Hang masses on two springs, compare stiffness, gravity and damping, and measure the bounce period. Drag, change the sliders and see the result live. No sign-up, works on phone and computer. Built for physics, the masses and springs: bounce lab 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.
Hang masses on two springs, compare stiffness, gravity and damping, and measure the bounce period. 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 Masses and Springs: Bounce Lab
- Use the controls to change Spring 1 stiffness, Spring 2 stiffness, Gravity, Damping. The simulation reacts instantly.
- Press "Stop bouncing", "Reset masses" 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
- Hang the 250 g mass on both springs.
- Change gravity to the Moon's value.
- Increase damping.
Key ideas you can learn
- Heavier masses stretch a spring more.
- Period T = 2π√(m/k).
- A stiffer spring bounces faster.
- Gravity changes the stretch but not the period.
Where this is used in the real world
Engineers use spring-mass models for suspensions, seismometers and vibration isolation.
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
What is the period of a mass on a spring?
T = 2π√(m/k): larger mass gives slower bounce, larger stiffness gives faster bounce.
Does gravity change the period?
No. It only shifts the resting position.
Is the Masses and Springs: Bounce Lab 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 Masses and Springs: Bounce Lab 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.