Walking on Quicksand – Carefully

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


About carlos

I'm a curious person, of reasonable intellect, "on the beach" (retired) and enjoying my interest in anthropology, language, civil rights, and a few other areas. I've been a hippie/student/aerospace tech writer in the '60s, a witness to the Portuguese revolution in the ‘70s, a defense test engineer and witness to the Guatemalan genocide in the '80s, and a network engineer for an ISP in the '90s. Now I’m a student and commentator until my time is up. I've spent time under the spell of the Mesoamerican pyramids and the sweet sound of the Portuguese language. I've lived in Europe, traveled in Brazil, Central America, Iceland, New Zealand, and other places. My preferred mode of travel is with a backpack and I eat (almost) anything local. Somehow, many of the countries I have been to have had civil unrest (for which I was not responsible). I'm open to correspond with anyone who might share my liberal, humanist interests. I live in San Buenaventura, California.
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