Equilibrium
Forces and Motion

Slinky Drop

At home for 5-11 11-14


What you need

  • A slinky
  • A friend

Instructions

  1. Hold the slinky up at arm’s length by its top coils
  2. With your friend keeping a close eye on the bottom of the slinky, let go of the top (you may need to do this several times to see what’s happening)

Results and Explanation

The bottom coil of the slinky remains stationary until the top coils reach it and then the whole slinky drops to the floor together!
When the top coils are released, the forces on the bottom coil (the tension in the spring and gravity) are still balanced. It is not until the slinky has contracted that gravity exceeds tension in the bottom coil and it starts to fall.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

Equilibrium
can be analysed using Force
has the special case Thermal Equilibrium
2021 IOP Awards

Teachers of Physics Award

Recognising and celebrating outstanding contributions to the field of physics education.

Learn more