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Over the years, we've explored the Sonic Universe from the depths of the ocean, all the way to the outer reaches of the solar system. We've talked about sound design, music, language, and history.

But one thing we've never really answered is what sound is on a fundamental level.

To make an episode about the physics of sound, we knew we needed someone who could break

down this complex subject in a way that's fun and accessible.

And there was one person who I thought would be perfect.

Dallas, greetings. Good morning.

Someone who inspired me back when I was a kid.

What happened? We're talking about sound. Yes.

His name is William Sanford Nye. But he's better known as...

Bill Nye, the science guy.

All right, go ahead, go ahead, you guys.

Sorry, let's get to work, people.

So for us, humans, sound is a pressure wave.

Now, everybody has a sense of what a wave is,

but stop and think about it.

...