I’ve been off doing other things than blogging this past week, since the Muse has not visited me of late, but this latest Internet fad is just too good to pass up commenting on.
To pevent their teachers from hearing their cell phones announce calls and messages, students are downloading a high frequency ringtone (about 17,000 Hertz) that the average adult cannot hear. The news has spread all over the ‘net and the news agencies so I won’t bother reviewing the story.
I will gloss on the meaning of “average,” though. The 17kHz (that’s kiloHertz, folks) tone cannot be heard by the average adult, since as we grow older, we lose sensitivity to the higher frequency range of the human ear (20 Hz – 20kHz). But average, by definition, is a measure of the middle of a set of data. So, some adults (like me!) can in fact hear those high frequency tones. (I can also sometimes hear the high frequency whine of TV and computer cathode-ray monitors, which use a high frequency oscillator to “draw” the picture.)
So, kiddoes, if you want to be absolutely sure your teacher cannot hear your pesky cell phone, try the “vibrate” feature and keep the phone off the desk.