f is for frequency

automatic captions, checked for structure and key terms; corrections welcome.

0:00[unclear opening audio]

0:35Hi, Ladyada.

0:37Oh, hey, Adabot. What's up?

0:38I was wondering, why do radio stations each have their own number?

0:43Oh, the number of a radio station is the frequency on which it transmits.

0:48What is this frequency you speak of?

0:51Well, frequency is how often something happens, like, per second.

0:56Huh.

0:57Oh.

0:58Um, you know, to explain it, I better use my trusty oscilloscope here.

1:03Only thing is, I gotta get the probes, so I'll be right back.

1:07Okay, wait here.

1:10Psst.

1:11Hey, over here.

1:13What?

1:13Who said that?

1:15Me.

1:16The talking screen over here?

1:18Oh, hello, talking screen.

1:20I'm not just a screen, I'm an oscilloscope, and I can tell you quite a bit about

1:25frequency.

1:26Really? Like what?

1:28Well, like Ladyada was saying, frequency is how often something happens over time.

1:34And we measure frequency in units called hertz.

1:38Oh, does frequency hurt?

1:41Oh no, that's a totally different word.

1:44Oh good.

1:45Hertz is spelled H-E-R-T-Z, and it tells us how many times

1:50something happens per second.

1:53Okay.

1:55Watch this.

1:57Right now, my screen is flashing once per second, so we can say it is flashing at

2:03a frequency of one hertz.

2:09now my screen is flashing a bit faster three times per second which is a

2:15frequency of three Hertz means how many times

2:21per second precisely so why is

2:25frequency important for radio stations good question you see a radio station

2:31uses a large antenna to send out waves of electromagnetic energy.

2:37We call these

2:38radio waves. Each station broadcasts

2:44at its own special frequency, so they don't

2:47get confused with another station. So, for example,

2:53when you tune your radio to

2:5593.9, you're telling it to only receive radio

3:01waves, which have a frequency of 93.9 million

3:06hertz. Your radio then converts those radio waves into

3:12sound, so you can hear the station,

3:14which broadcasts at that particular frequency.

3:18This is 93.9 WBOT, the bot.

3:24all that happens so I can hear music yes it does amazing

3:29indeed and frequency is

3:32important for audio as well like sound waves from a speaker exactly

3:38a sound

3:39wave is a vibration moving through the air and the frequency of a sound wave

3:45determines the pitch of that sound a slow-moving or low-frequency

3:52wave sounds

3:53low-pitched and bassy and a fast-moving high-frequency

4:00wave has a much higher

4:05pitch.

4:06So slow waves sound low

4:08and fast waves sound high?

4:10That's right. Found them!

4:12Oop, someone's coming.

4:14I've got to go. Take care,

4:16Adabot, and stay curious.

4:18Thank you, oscilloscope.

4:19I will.

4:21Okay, I found my oscilloscope

4:24probe. Sorry it took me so long, but now

4:26I'm going to hook them up to my oscilloscope here

4:28and I'm going to be able to teach you all

4:30about frequency.

4:31No need, Ladyada. It all makes sense now.

4:34Really?

4:35Eh-eh-eh-eh. Frequency is how often something happens over time.

4:40Frequency helps us tune into radio waves or create a sound wave at a certain pitch.

4:45Wow, you do know a lot about frequency. Where'd you learn all of that?

4:49Well, my friend the oscilloscope taught me a lot.

4:53Uh, hey, oscilloscope, you okay in there?