Dangle a slinky off the roof of a building until it is fully extended, then let go and notice something odd: The bottom will hover in mid-air long enough to make even the casual observer to go, “huh?” Thankfully, scientists have taken it upon themselves to explain this strangeness.
And they’ve done it with the help of high-speed video so that we can watch the suspended, collapsing spring in super slow motion.
Mike Wheatland from Australia’s University of Sydney explains in the video below that when you let go of the slinky at the top, “there’s a finite time for that information (i.e. signal) about that change to get to the bottom of the slinky.”
Until the bottom of the slinky gets the message, it just hangs there oblivious to the change happening form above. Hence, the hovering effect.
For a bit more technical explanation, check out the explanation at io9. You can also geek out to the physics of slinkys by reading this paper on arXiv by Bill Unruh, a physics professor at the University of British Columbia.
Of course, you can also stare at the slinky and let time slip away one collapsed coil at a time.
John Roach is a contributing writer for msnbc.com. To learn more about him, check out his website and follow him on Twitter. For more of our Future of Technology series, watch the featured video below.