Yesterday, I imagined calling these friends, who I haven't talked to in an unforgivably long time (see yesterday's post). And I heard each of them take in a quick breath of air, exhale in a half-whistle, and say something to this effect: "Hmm, I'm not sure. Lets look it up." Followed by twenty seconds of key strokes, silence and/or small talk until the moment the search terms "dogs + light & sound frequencies" revealed something like the following:
Recall that the frequency range for human hearing is 20 Hz – 20 000 Hz
- 20 000 Hz can be written as 20 kHz.
- Electronic systems can be used to produce electrical oscillations with any frequency.
- These electrical oscillations can be used to produce ultrasonic waves, which have a frequency higher than the upper limit of the hearing range for humans.
- Some animals such as bats and dolphins emit ultrasonic sounds. Even more animals, such as dogs, can hear them.
My friends would have said something like, "Well, Marcus, this might be your answer. Maybe Eliot is hearing the
sound waves emitted from the motion sensor, which sends something like radar through the room to detect motion--." I probably should have called them first. Don't nominate me King Luddite. I don't deserve it after all.
2 comments:
I think I've had some good posts lately (after dogging it for 3 months). But I seem to be blogging into the darkness most of the time. Nice to know every now and then someone stops by. Thanks man...
--M
Hi Marcus,
Thanks for sharing my recent good news! I'll be adding your blog to my roll now that I know you're out there. :)
Angela
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