F is for Frequency

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

[00:00:00.000] [unclear opening audio]
[00:00:35.860] Hi, Ladyada.
[00:00:37.160] Oh, hey, Adabot. What's up?
[00:00:38.940] I was wondering, why do radio stations each have their own number?
[00:00:43.080] Oh, the number of a radio station is the frequency on which it transmits.
[00:00:48.380] What is this frequency you speak of?
[00:00:51.700] Well, frequency is how often something happens, like, per second.
[00:00:56.720] Huh.
[00:00:57.760] Oh.
[00:00:58.600] Um, you know, to explain it, I better use my trusty oscilloscope here.
[00:01:03.420] Only thing is, I gotta get the probes, so I'll be right back.
[00:01:07.560] Okay, wait here.
[00:01:10.760] Psst.
[00:01:11.500] Hey, over here.
[00:01:13.340] What?
[00:01:13.920] Who said that?
[00:01:15.400] Me.
[00:01:16.240] The talking screen over here?
[00:01:18.700] Oh, hello, talking screen.
[00:01:20.700] I'm not just a screen, I'm an oscilloscope, and I can tell you quite a bit about
[00:01:25.520] frequency.
[00:01:26.580] Really? Like what?
[00:01:28.100] Well, like Ladyada was saying, frequency is how often something happens over time.
[00:01:34.580] And we measure frequency in units called hertz.
[00:01:38.960] Oh, does frequency hurt?
[00:01:41.280] Oh no, that's a totally different word.
[00:01:44.500] Oh good.
[00:01:45.200] Hertz is spelled H-E-R-T-Z, and it tells us how many times
[00:01:50.900] something happens per second.
[00:01:53.600] Okay.
[00:01:55.080] Watch this.
[00:01:57.900] Right now, my screen is flashing once per second, so we can say it is flashing at
[00:02:03.760] a frequency of one hertz.
[00:02:09.440] now my screen is flashing a bit faster three times per second which is a
[00:02:15.520] frequency of three Hertz means how many times
[00:02:21.500] per second precisely so why is
[00:02:25.080] frequency important for radio stations good question you see a radio station
[00:02:31.160] uses a large antenna to send out waves of electromagnetic energy.
[00:02:37.160] We call these
[00:02:38.580] radio waves. Each station broadcasts
[00:02:44.340] at its own special frequency, so they don't
[00:02:47.280] get confused with another station. So, for example,
[00:02:53.420] when you tune your radio to
[00:02:55.640] 93.9, you're telling it to only receive radio
[00:03:01.420] waves, which have a frequency of 93.9 million
[00:03:06.820] hertz. Your radio then converts those radio waves into
[00:03:12.280] sound, so you can hear the station,
[00:03:14.840] which broadcasts at that particular frequency.
[00:03:18.300] This is 93.9 WBOT, the bot.
[00:03:24.300] all that happens so I can hear music yes it does amazing
[00:03:29.280] indeed and frequency is
[00:03:32.240] important for audio as well like sound waves from a speaker exactly
[00:03:38.220] a sound
[00:03:39.940] wave is a vibration moving through the air and the frequency of a sound wave
[00:03:45.660] determines the pitch of that sound a slow-moving or low-frequency
[00:03:52.280] wave sounds
[00:03:53.660] low-pitched and bassy and a fast-moving high-frequency
[00:04:00.220] wave has a much higher
[00:04:05.040] pitch.
[00:04:06.380] So slow waves sound low
[00:04:08.060] and fast waves sound high?
[00:04:10.200] That's right. Found them!
[00:04:12.720] Oop, someone's coming.
[00:04:14.220] I've got to go. Take care,
[00:04:16.100] Adabot, and stay curious.
[00:04:18.520] Thank you, oscilloscope.
[00:04:19.880] I will.
[00:04:21.960] Okay, I found my oscilloscope
[00:04:24.100] probe. Sorry it took me so long, but now
[00:04:26.020] I'm going to hook them up to my oscilloscope here
[00:04:28.140] and I'm going to be able to teach you all
[00:04:30.100] about frequency.
[00:04:31.840] No need, Ladyada. It all makes sense now.
[00:04:34.620] Really?
[00:04:35.700] Eh-eh-eh-eh. Frequency is how often something happens over time.
[00:04:40.260] Frequency helps us tune into radio waves or create a sound wave at a certain pitch.
[00:04:45.640] Wow, you do know a lot about frequency. Where'd you learn all of that?
[00:04:49.340] Well, my friend the oscilloscope taught me a lot.
[00:04:53.980] Uh, hey, oscilloscope, you okay in there?