From the brains behind Brains On, this is The Moment of Um. Um, Um, Um, Um, Um, Um, Um, Um, Um, Um, Um, Um. Hi, it's me, Molly Bloom, host of Brains On,, Smash Boom Best, and three-time runner-up of the

international ferret sweater knitting contest. Or, as I like to call it, second-place champion.

You know, if I was going to be known for anything, I always thought it would be one of my many

talents, like throwing bad drafts of essays into the garbage can. She shoots in?

Perfect swish, like always.

Or maybe my ability to make portraits of famous presidents with nothing but a tissue and a nose blow.

Check it out.

It's Bougarham Lincoln.

That's a good one.

Or the fact that I can write my name with my feet.

Like this? See? Merleblowum. Yeah, that's what I meant to write. But it turns out most people just know me because of my voice.

That's the life of a podcaster, I guess. Since my voice is so important to my public persona, you'd think I'd know more about how it works. I know something called vocal cords

are involved, but what are they? Nor wanted to know, too. Let's get the scoop from a doctor.

Vocal chords are really cool, and they're really important my name is emma gershton zang and i'm a pediatrician in philadelphia whenever you talk or sing or yell or whisper

air flows from your lungs it goes up through your windpipe, and it goes past your vocal cords.

If you don't have air flowing back and forth, you can't speak. So try holding your breath and saying

something at the same time. You can't do it. What's happening is when air flows past your vocal

cords, they get pulled back and forth by muscles that are surrounding them. So there's muscles

that surround your vocal cords, and they pull the vocal cords back and forth really, really fast,

so fast that they're actually vibrating.

And so when something's vibrating,

then it changes how the air flows past it,

...