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Hang a toy on a big spring and let go. Does a heavier toy bounce faster or slower?
Bungee Toy lab · Last updated: 16 October 2026
You hang a toy on a big spring, pull it down and let go. The toy bobs up and down in a steady rhythm. The question is simple and surprising: does a heavier toy bounce faster or slower?
What you'll discover
- A toy on a spring bobs up and down with a steady, repeating rhythm.
- A heavier toy bounces more slowly, and a stiffer spring makes it bounce faster.
- How far you pull it down hardly changes the time for one bounce.
The science in plain words
A spring pulls back harder the further you stretch it. This is called Hooke's law: double the stretch and the pull doubles. When the toy is pulled below its resting point, the spring pulls it up; when it rises above, gravity and the spring send it back down. It overshoots each time, so it keeps bobbing.
This kind of back and forth movement is called oscillation, and the time for one complete up and down is the period. For a mass on a spring the period depends on two things: how heavy the toy is and how stiff the spring is. A heavier toy is harder to speed up and slow down, so each bounce takes longer. A stiffer spring pulls harder, so it bounces faster. Four times the mass doubles the period.
Surprisingly, how far you pull the toy down makes little difference to the period. A bigger pull means a stronger force, so the toy moves faster and covers the extra distance in about the same time.
In real life, bounces slowly die away because of air resistance and friction inside the spring. Car suspension, bungee jumps and even weighing scales all rely on the same idea.
Where it fits
- India, NCERT: Spring oscillation goes beyond the NCERT syllabus for classes 6 to 10; it builds on periodic motion in Class 7 Chapter 8: Measurement of Time and Motion.
- United States: Grades 9 to 12
Common questions
Does a heavier weight bounce faster on a spring?
No, it bounces more slowly. A heavier mass is harder to speed up and slow down, so each up and down takes longer. To make it bounce faster you need a stiffer spring or a lighter weight.
What is Hooke's law in simple words?
Hooke's law says the force a spring pulls back with is proportional to how far you stretch it. Stretch it twice as far and it pulls twice as hard, as long as you do not overstretch it.
Why does a bouncing spring eventually stop?
Each bounce loses a little energy to air resistance and to tiny amounts of heat inside the spring. Bit by bit the bounces get smaller until the toy hangs still at its resting point.
Related labs
- Simple Pendulum: Time one swing. What changes it: the string, the bob, or the push?
- Resonance: Shake three toys on springs gently. Why does only one go wild?
- Bouncing Balls: Drop a rubber ball from 30 cm. How high does it come back?
See all physics labs or every Taz science lab.
Try it yourself
The Bungee Toy lab is one of the interactive 3D science labs inside Taz. Change one thing, predict what will happen, then run it and watch. Labs open after you sign in.