Researchers at the University of Waterloo have made a surprising discovery: tiny spheres can roll vertically on soft surfaces without any external force. The phenomenon was accidentally observed by a team including postdoctoral fellow Surjyasish Mitra while studying another concept.
Mechanical engineering professor Sushanta Mitra explained that the effect relies on precise elasticity between a pea-sized ball and a vertical slide, roughly the size of a cellphone screen. The soft, sponge-like surface—similar in consistency to a gummy bear—interacts with the sphere through opening and closing micro-cracks, functioning like zippers to generate motion.
“This marble will actually roll down, instead of just falling,” Mitra said, calling the movement nearly a defiance of known physics. The ball progresses slowly—just one millimetre every two seconds—and the team used microscopic imaging to confirm the effect through repeated experiments.
Despite the minute movement, the implications are significant. Postdoctoral fellow A-Reum Kim noted the difficulty in capturing the behavior under a microscope due to the limited field of view.
The team is now exploring potential applications, such as robotic drug delivery, human-centered technologies, and even Mars exploration, where motion without external energy sources could prove critical.
Swifteradio.com
