Q: Why do you hear the sound of the ocean when you hold a seashell to your ear?
—Nicola Ward, San Francisco
A: This “sounds” like an answer: Just cup your hand in front of your ear to expand its size and you will hear the same thing—although it probably won’t be as loud. A drinking glass works, too. While people have argued that the “ocean” sound is really blood rushing through the vessels of your ear, or air flowing through the shell, the most likely culprit is ambient noise. The seashell, held just above your ear, captures this noise and acts as a resonating chamber. The noisier your environment, the louder the sound, which explains why your shell sounds louder on the beach on a stormy day than it does in your bedroom.
—Thanks to Professor Marian Diamond from the Integrative Biology Department
From the July August 2007 Summer Travel Issue issue of California.