Our friend The Giant Squidstravaganza sent us a present from the beach: awesome seashells!

Have you ever put a shell over your ear and listened very carefully? If you have, you might’ve heard a sound that sounds a lot like the sound of the ocean!

But the sound inside the shell isn’t caused by the ocean at all! The sound that we hear inside the shell actually comes from the sounds that are all around us All of the sounds we hear are made by vibrations. When something vibrates, it moves back and forth really fast.

Most of the time, it moves so fast that our eyes don’t even see it. For example, if you ring a bell, you’re causing the metal that makes up the bell to vibrate back and forth really fast. The vibration of the bell also shakes up the air around it, and makes it vibrate.

When the vibrating air reaches our ears, the vibrations send a message to our brains, and we hear a sound. Now, the thing is, even when we think things are pretty quiet, there are noises all around us, all of the time. The noise might be the noise from cars going by, or the breeze blowing through the trees.

Even the beating of your heart makes some noise! And all of these sounds are sending vibrations to our ears. But most of the time, we don’t think about them too much because we’re busy doing other things For example, right now, your brain is focusing on hearing my voice and helping you to learn and understand what I’m saying, even though there are at least some other noises around you But when we put something over our ears, like a shell, it changes the way the vibrations from all of the background noises reach our ears.

The shell causes some of vibrations from these background sounds to bounce around a lot and get a lot louder. When we listen to and focus on these vibrations coming out of the shell, our brains pay close attention too! They make a kind of roaring sound that reminds our brains of the sound that the ocean makes!

You can try an experiment to hear this at home, and you don’t even need a seashell! Ask a grownup for a plastic cup, or a small plastic bowl. You’ll need to find a place where there’s some background noise, but not a place where it’s too loud.

Then, all you need to do is to put the cup over your ear … and listen! Do you hear it, Squeaks? So do I!

I hear a soft roaring sound. The cup is causing some of the vibrations from the background noise in the room to bounce around, just like a seashell does. Shells with different sizes and shapes will cause the vibrations from the background noise to bounce around in different ways, so when you listen to them, you might hear different kinds of roars.

And different background noises can also change the sound we hear inside the shell. You can test this out for yourself! Try using different kinds and sizes of cups, or listening in different places in your house or outside.

Does it change the sound you hear? Squeaks and I are going to spend some time today trying our experiment in lots of different places around the Fort … right after we write a thank you note to The Giant Squidstravaganza for the beautiful shell! Did you try this experiment?

What did you learn? Ask a grownup to help you leave a comment below, or send us an email at kids@scishow.com. We’ll see you next time here at the Fort!