  By precisely monitoring the "ticks" of Nature's most precise clocks
(millisecond pulsars), scientists are trying to detect the "ripples in
spacetime" (gravitational waves) produced by the inspirals of supermassive
black holes in the centers of distant merging galaxies. Here we describe a
relatively simple demonstration that uses two metronomes and a microphone to
illustrate several techniques used by pulsar astronomers to search for
gravitational waves. An adapted version of this demonstration could be used as
an instructional laboratory investigation at the undergraduate level.
