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Why Do Seashells Sound Like the Ocean?

Little girl with shell on the beach
gorillaimages/Shutterstock

We’re all guilty of putting a seashell up to our ears to hear the ocean within. It’s something most of us do as children, and maybe as adults as well. But, what you’re hearing isn’t necessarily the ocean.

What It Sounds Like Holding a Seashell to Your Ear

You grab a conch shell and put it to your ear. You’re not by an ocean; you’re in a thrift shop looking for home decor. The shell brings what you perceive as the sound of rushing waves into your head. You think of sandy beaches and dolphins leaping in the deep waters. You have a great imagination, but you do not hear water.

Of course, if you are putting a shell to your ear while standing by the water, you hear water—just not the way you think. There’s no magic inside that seashell; it’s science.

What You’re Not Hearing

It was once thought that what you might be hearing when you put a seashell to your ear was the sound of your blood rushing through your body. The sound of the blood moving through your head is something some people can experience simply by laying their head down on a pillow or when you put earplugs in your ears.

To prove that you do not hear your blood pumping through your veins when you hold a shell to your ear, you can try a quick experiment. Listen. Then, do a quick cardio workout to get your blood flowing. Listen again. The “ocean” sounds will be the same, not louder.

It is also not merely air flowing through the shell, creating a wooshing noise similar to the sound of the ocean. Some compare the sound you hear in the seashell to that you get when you blow in a glass soda bottle, but that’s not what is happening. Blowing into a bottle makes a musical note. You can find conch shells turned into musical instruments that you can blow into and get a horn sound from, which is helped along by the shell’s resonance abilities, but it’s not the same as listening to the shell itself. Tests have been done in soundproof rooms, where air still flowed, but no sound was heard in the shells.

What You are Hearing

What you hear when you put a shell to your ear is the sound of the environment resonating into the chamber of the shell, known to many as seashell resonance. Sounds from outside the shell enter into it and bounce around, resinating the noise into your ear when you give it a listen.

The conch shell is one of the most popular shells to which we enjoy listening to the rushing sounds of resonance, but any thusly shaped shell will do the trick. It is, after all, all about the shape of the shell. The sound simply needs a place to enter and bounce around, a chamber.

You can get this same kind of sound “reaction” by putting a cup up to your ear. You’ll hear the sounds around you magnified, though muffled, a bit (think of when you used the cups on a string to “telephone” your friends from one room to another). Think of it like a speaker expanding the sounds around you.

Louder noises outside the shell, like madly crashing waves, will make what you hear inside the shell louder. If you listen to the shell in a quiet room, you’ll still hear a sound, but it won’t be as loud. The shell can still pick up ambient sounds from your electronics, the furnace running, or anything else that makes an audible sound.

If you want to try out the effects of listening to a seashell but don’t have a seashell? You can cup your hands over your ears and get the same effect!

Yvonne Glasgow Yvonne Glasgow
Yvonne Glasgow has been a professional writer for almost two decades. Yvonne has worked for nutritionists, start-ups, dating companies, SEO firms, newspapers, board game companies, and much more as a writer and editor. She's also a published poet and a short story writer. Read Full Bio »