The science behind a slow-motion Slinky
A YouTube video of a Slinky falling from the top of a building in ultra-slow motion demonstrates the beauty of science.
At first glance, the giant Slinky almost appears to be floating. But a closer look shows the bottom of the toy hanging in mid-air while the top collapses toward it.
Scientists have been analyzing the phenomenon, explaining that gravity pulls the top of the Slinky down, but the tension in the coil pulls the bottom up. When the top is let go, a compression wave travels down the toy, and the Slinky doesn't start falling until that wave hits the bottom.
"You're changing something at the top and then there's a finite time for that information about the change to get to the bottom of the Slinky," says physicist Mike Wheatland. "That happens even with a rigid bar. It's just that the time is very, very short."
The video, the final one in a six-part series about the Slinky, puts a new twist on the classic toy, which was developed by a U.S. naval mechanical engineer in the early 1940s.