Frequency
From the site:
"Most humans are born with the ability to hear frequencies from about 20 Hz (low) up to 20,000 Hz (high) but that range shrinks as we get older. A guy in England figured that meant kids can hear things adults can't - specifically, very high frequencies. He created a device that pulses an annoying tone at about 15,000 Hz with the idea that when the device is used, it will repel kids while being unnoticed by adults. "
Site includes a frequency threshold test. I thought it was kinda cool.
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1 comment:
interesting, as i was just reading something similar about someone who created a ringtone in a frequency that only kids can here, and apparently was being semi-secretly downloaded and passed around by kids so they could text message each other in class without the teacher knowing it.
goes both ways i guess. :)
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