IPB

Does a Slinky Defy Gravity?

12. January 2026.

The new December Monthly Physics Challenge has been released! This month, we are experimenting with a well-known toy – the Slinky. Do you remember it?

A Slinky is placed vertically in the Earth’s gravitational field, and at the initial moment, its upper end is held by young researchers from the Institute of Physics Belgrade. At one point, they release it, and the Slinky then falls freely in the Earth’s gravitational field. However, this fall is rather unusual. The lower end of the Slinky is at rest, giving an impression that gravity does not act on it. Read what the task is and solve the December challenge! The rules of the challenge are HERE.