Video: Weighted Ping-Pong Balls Fall Indefinitely Through a Granular Medium
Reaching Terminal Velocity in a Granular Medium Yeah, it's possible. Defying intuition, dense enough materials can reach terminal velocity within granular solid media. A team of Mexican and Cuban researchers have made a somewhat mind-bending discovery. They've shown that objects crashing through a granular medium don't necessarily lose energy and come to a stop, as you might expect, but can attain a terminal velocity and continue sinking indefinitely into the material. It's a property that has never been observed or, to the researchers' knowledge, even predicted before. Specifically, the team used a set of 18 weighted ping-pong balls ranging from 15 to 182 grams (that's not even a half-pound at the high end), and launched them into a large tube filled with polystyrene beads. One would imagine, normally correctly, that a ball would enter the polystyrene medium and begin to lose velocity via friction and the beads' resistance to the force of...