>> Rachel: Good morning, it’s time for Chompers: your morning and night toothbrushing show. 

Start brushing on the top of your mouth on one side, but don’t brush too hard. 

>> KIDS: 3, 2, 1 brush!

>> Rachel: It’s Sounds week, and today we’ve got some RIDDLES!

Here’s your first one: 

I travel like a rollercoaster

People say I’m high or low

Because I go up and down

Really fast, or really slow

What am I?

>> GROUP: The frequency of a sound!

>> KID: Huh?

>> Rachel: I’ll explain, after you Switch your brushing to the other side of the top of your mouth, and brush your molars in the back of your mouth too.

Remember sound is made of waves! And waves go UP! And DOWN!

And waves can go up and down A LOT!  (SFX)

Or waves can go up and down just a little (SFX)

If the sound waves go up and down a lot, it’s a high frequency

If the sound waves go up and down only a little, it’s a low frequency. 

Switch to the bottom of your mouth, pick a side and keep brushing! 

So why does that matter? When the waves go up and down a lot -- when they’re HIGH frequency -- you hear a high note. (SFX high note). 

When the waves go up and down only a little -- when they’re LOW frequency --  you hear a low note (SFX low note). 

Here’s your next riddle: 

I’m really just a regular sound

But even if you’re close by

It’s impossible to hear me

Because I’m just too high

What am I? 

Switch to the other side of the bottom of your mouth, but keep making circles around each tooth with your brush. 

So … what’s the answer?

>> GROUP: Ultrasound

>> Rachel: Ultrasound is a sound that humans cannot hear. Ultrasound waves go up and down too fast for us -- the sound is too HIGH for us to hear. But some animals can hear ultrasound. You may have seen a dog start barking for what seems like no reason -- but sometimes when dogs bark (SFX), it’s because they hear ultrasound -- something we can’t hear! 

That’s it for Chompers today, but come back for more riddles tonight. Until then, 

>> KIDS: 3, 2, 1 spit!