What happens when you drop a regulation Spalding basketball from a 415-foot-high dam? It depends.
For a group from the trick basketball team How Ridiculous who sank a basket from atop the Gordon Dam in Tasmania, it meant landing a spot in the Guinness World Records book.
But at the same time, the record breakers were able to demonstrate a bit of science: It turns out that by giving the ball a little spin before its release, it can appear — at least momentarily — to defy gravity. The resulting video, posted on the YouTube channel Veritasium, has gone viral.
The explanation is something called the Magnus effect, after physicist Gustav Magnus, who described how it works in 1852.
As Australia’s 7 News describes it:
“[As] the ball spins through the air, the air on one side of the ball goes in the same direction as the spin and is deflected behind the ball.
“While on the other side, the air is flowing opposite to the spin and is deflected away. So the air that is spinning with the ball applies an opposite force, pushing the ball forward.”
(The Magnus effect has to do with the physics of curve balls in soccer, too.)