From the brains behind brains on, this is the Moment of Um.

Um, um, um, um, um, um, um, um, Momit of Um comes to you from 8pm Studios. I'm Coco Puff, the Toy Poodle, and today's my birthday.

Um, I just love birthdays, don't you?

For one day a year, I get to do whatever I want.

If I want to fetch five different squeaky toys at once, I do it.

If I want to go down to the ice cream shop and get the world's biggest strawberry milkshake, I do it.

And if I want to throw a huge birthday party and invite everyone in my kennel, I do it. And if I want to throw a huge birthday party and invite everyone in my

kennel, I do it. This year, my friends and I are having a retro-themed birthday party. We're all

going to dress up like super old stuff, like those phones that used to be attached to the wall with

long, curly cords, or all the members

of one direction before Harry Stiles went solo? Oh, actually, that reminds me, maybe we should

listen to some really old music too, like on a radio. Radios are so vintage. You turn them on and you hear stuff.

You move the dial thingy and you can just tune in different stations, each with its own

type of music.

Plus, you can flip the dial to AM or FM, whatever that means.

Hey, that's actually a really good question. What do AM and FM mean for

radios? So I think the best way to think about radio waves, in my opinion, is to think about

waves that we are familiar with. My name is Angie Werta, and I'm a graduate student at the University of Notre Dame studying physics.

An example of that can be the waves in an ocean. When it comes to radio waves, FM waves, which

stands for frequency modulation waves and AM waves, which stand for amplitude modulation, are two different ways to change the shape of a wave.

FM changes how close or how frequent the waves are coming in.

Kind of like squeezing a slinky together and then pulling it apart.

...