The physics of a popsicle stick bomb

Abstract

Popsicle sticks can be interlocked in the so-called “cobra weave” to form a chain under tension. When one end of the chain is released, the sticks rapidly disentangle, forming a traveling wave that propagates down the chain. In this paper, the properties of the traveling front are studied experimentally, and classical results from the theory of elasticity allow for a dimensional analysis of the height and speed of the traveling wave. The study presented here can help undergraduate students familiarize themselves with experimental techniques of image processing, and it also demonstrates the power of dimensional analysis and scaling laws.