How Does Sound Travel?

Clap your hands! Did you hear that? SMACK! It zooms across the mat! But how did the noise get from there to you? What did it ride on, what passed it through?

Sound is a WIGGLE in the air! Tiny molecules, EVERYWHERE! You push the first one — POOF! It pushes the next! The next pushes the next, like a chain in your text!

Wiggle! Wiggle! Push push push! Through the air with a SHHH and a WHOOSH! Wiggle! Wiggle! Bump bump bump! 'Til it tickles your ear with a tiny THUMP!

Inside your ear is a stretchy skin — A drum so thin it can be pushed in! The wiggle hits — your eardrum shakes — Your brain wakes up and "HEARS" the quakes!

Wiggle! Wiggle! Push push push! Through the air with a SHHH and a WHOOSH! Wiggle! Wiggle! Bump bump bump! 'Til it tickles your ear with a tiny THUMP!

Sound can ride on water too — Whales sing for miles, they really do! Sound can ride on a wooden floor — Stomp stomp stomp! It travels more!

But sound needs SOMETHING to wiggle through — With nothing to push, there's no sound for you! No air? No water? No string? No floor? Then the noise just stops at its tiny door!

How do we know? How do we know? Robert Boyle, sixteen-sixty or so, Put a little bell inside a jar, Pumped the air OUT — pushed it far!

The bell swung, the bell swung high, The clapper hit, but you'd hear no cry! No air to wiggle, no air to push — Just silent ringing in the empty hush!

When he let the air come BACK on in — The bell rang loud, the sound began! Air was the carrier all along — Boyle proved the carrier of song!

Wiggle! Wiggle! Push push push! Through the air with a SHHH and a WHOOSH! Wiggle! Wiggle! Bump bump bump! 'Til it tickles your ear with a tiny THUMP!

So when you yell across the yard, A trillion molecules push real hard, Hand the wiggle from one to one, Right to your friend's ear — the trip is done!