Bullroarer

DCS Code: 3D40.65 Last Updated: March 27, 2026
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Safety Warnings

Purpose

A spinning metal ruler on a string produces a rhythmic rumbling sound and demonstrates coupled rotational motions, aerodynamic lift, and sound generation from a vibrating solid.

A 12-inch Westcott metal ruler with a long loop of white string threaded through a hole at one end, laid on a gray surface
Figure 1: The bullroarer: a 12-inch metal ruler attached to a loop of string.
Demo Apparatus