Weighted ping-pong balls can fall endlessly through a granular medium (w/ video) June 27, 2011 by Lisa Zyga
So, you thought quicksand was just mud – a myth? Apparently not, and why should it be? We’ve heard about “liquefication” during earthquakes when saturated loose soil shakes becomes more like a thick chocolate milkshake than bedrock. I’m assuming that the impact of the ball has “liquefied” the loose styrofoam.
This partial image taken from the video below shows a projectile near the beginning of its trajectory as it falls through a tube filled with granular matter. Image credit: F. Pacheco-Vázquez, et al. ©2011 American Physical Society
(PhysOrg.com) — When a meteor impacts a planet or a moon, it always stops at a relatively shallow depth, even when impacting at high speeds. Until now, researchers have assumed that all objects impacting a granular medium – such as sand or beads – rapidly lose energy and stop at a shallow depth. But in a new study, researchers have demonstrated that weighted ping-pong balls impacting a 600-cm (20-ft)-long tube filled with polystyrene beads can reach a terminal velocity, which allows the balls to continue sinking endlessly to an infinite depth. Video of weighted pingpong balls