[Jessi:] Oh, hi Sam!

[Sam:] Hey there, Jessi!

[Jessi:] This is our friend Sam the Bat! Sam’s visiting the Fort today.

[Sam:] Hey everyone!

[Jessi:] Sam, want to see a cool trick I can do with this balloon?

[Sam:] I like cool tricks and balloons!

[Jessi:] Me, too. Okay, here goes. [Jessi lets air out of the balloon and changes the pitch of the sound of the air coming out by pulling the neck of the balloon.]

[Sam:] Whoa! How did you get that balloon to make different kinds of sounds?

[Jessi:] Well, when I pull the balloon tight, so there’s only a tiny little space for the air to come out, it makes a high sound. Jessi demonstrates.

[Sam:] Interesting!

[Jessi:] And when I don’t pull it as tight, so the air comes out of a bigger space, it makes a lower sound.

[Sam:] I see!

[Jessi:] But you want to know something really cool?

[Sam:] What?

[Jessi:] This balloon is actually a lot like the way people can sing.

[Sam:] What do you mean?

[Jessi:] Well, try singing a high note. [Sam sings a high note.]

[Jessi:] Wow, great singing!

[Sam:] Why, thank you!

[Jessi:] So when you hit that high note, you tightened something down in your throat, inside your neck. They’re called your /vocal folds/ which are like folds of skin. People also sometimes call them vocal cords.

[Sam:] I tightened my vocal folds? Really? But I’ve never even heard of them!

[Jessi:] That’s because we do it without even thinking about it! You don’t have to think to yourself, “Now I’m going to tighten my vocal folds.” You just sing that high note, and your body knows what to do.

[Sam:] That’s really neat. And let me guess, when I sing a low note… shall I?

[Jessi:] Please! [Sam clears his throat, then sings a low note.]

[Jessi:] Lovely!

[Sam:] Thank you! So when you sing a low note, the… what were those called?

[Jessi:] Vocal folds.

[Sam:] The vocal folds aren’t as tight. Is that right?

[Jessi:] Exactly. So you know how a balloon has air in it? That’s what I was letting out of the balloon.

[Sam:] Yep!

[Jessi:] Remember how I controlled how much air I let out? If I held it tight, not much air was let out. And if I held it a little looser, more air came out.

[Sam:] Right!

[Jessi:] So when I held it tight, the air coming out made the neck of the balloon vibrate, or move back and forth, really really fast. That’s what made the high sound! And when I held it a little looser, the balloon didn’t vibrate as fast, so it made a lower sound. When we sing, our lungs and throat are kind of like this balloon.

Our lungs are located in the middle of our body, in our chest, and they fill up with air, and then let that air out. That’s how we breathe! We take air in and we breathe it out. [Jessi demonstrates breathing and Sam breathes with her.]

[Jessi:] Breathe in. And breathe out. We let out air when we talk or sing, too. Your lungs deliver air to something called the /larynx/, which is in the middle of your throat.

And those vocal folds we talked about are on the top of the larynx. Then that air travels through your throat and your mouth. And just like the air coming out of the balloon made a sound because it made the neck of the balloon vibrate, when you talk or sing, the air traveling through your throat makes your vocal folds vibrate.

[Sam:] Wow, that’s [singing] /amaaaazing!/

[Jessi:] Beautiful, Sam! Did you know that professional singers actually work on training their breath so they have a whole lot of control over it, so they can make a really soft sound — [Sam sings a really soft sound]

[Jessi:] -- or a big, bold sound! [Sam sings a big, bold sound]

[Jessi:] Their vocal folds aren’t really different from anyone else’s; it’s that control that makes the difference.

[Sam:] Wow, cool!

[Jessi:] Sam, can I show you one more thing?

[Sam:] Sure! [Jessi pulls out a rubber band. She plucks the rubber band.]

[Jessi:] See how when I pluck the rubber band, it makes a sound, but it’s not that loud?

[Sam:] Uh-huh.

[Jessi:] But what about when I pluck that rubber band inside this box?

[Sam:] Let’s see! Jessi plucks the rubber band inside a box. It makes a deeper, richer sound.

[Sam:] Oh, it’s definitely louder now, and nicer sounding, too.

[Jessi:] You can think of the rubber band as like your vocal folds. It vibrates when I pluck it, just like your vocal folds or the neck of the balloon. The box is like your throat and mouth. They help make your voice sound fuller and louder.

[Jessi:] Well, I think I’m going to go play my favorite instrument.

[Sam:] What’s that, Jessi? Mine’s the piano.

[Jessi:] I do like the piano! But really, my favorite instrument is my voice!

[Sam:] Ohhhh! Well then, let’s go play!

[Jessi:] Thanks for joining us! If you want to keep learning more about our amazing bodies and our incredible world, hit the subscribe button, and don’t forget to check us out on the YouTube Kids app. We’ll see you next time, here at the Fort!

[Sam:] Bye!