Why Do Seashells Make Noise?

The shape of seashells just happens to make them great amplifiers of ambient noise. Any air that makes its way into a shell's cavity gets bounced around by its hard, curved inner surfaces. The resonating air produces sound. ... Whether high or low in pitch, almost all shells sound pleasantly ocean-like.

What is the sound you hear when you put a seashell next to your ear?

The most likely explanation for the wave-like noise is ambient noise from around you. The seashell that you are holding just slightly above your ear captures this noise, which resonates inside the shell. The size and shape of the shell therefore has some effect on the sound you hear.

Why do we hear sound in seashells?

The first part of the explanation is that the shell acts like a 'resonator'. When you blow air strongly through your pursed lips over the mouth of an empty bottle, you will hear a musical note. The sound is resonating in the bottle.