occur almost anywhere there is periodic motion. We have
already encountered such periodic motion in the back-and-forth movement
of pendulums and masses on a spring and with the cyclic orbits of
objects in a gravitational field. The physics of waves is also central
in explaining how light and sound work. Anything from a violin string
to a drum skin to a wine glass can make a sound, suggesting that
there are few things in the world that cannot produce wave phenomena.
We find waves in the air, in our bodies, in earthquakes, in computers—and,
if we’re surfers, at the beach.