I didn't hear anything and I'm only 15... is that a bad thing?

An oscilliscope is a nice idea, but so many things make so many odd noises, it may not be the best idea

Cure, if you've ever heard a phone on vibrate in the middle of a silent classroom, you'll know that it makes a distinct humming sound from the motor inside the phone, especially if it's resting on the floor or the bottom of a bookbag.

My father is freakin' 60, and he hears it!

good idea Lawrence!

the thing is most of them are traffic lights with green yellow and red lights, so it may not show, but i really do not know

Hey I just thought of something, I'm sure most schools have a few oscilliscopes lying around, they could just give some to the teachers. Then they'd be able to detect every frequency, even the ones only dogs can hear

Christ this is sooo old. My school was doing it ages ago, and it wasn't as much for ringtones as for pissing other people in the class off. They'd turn it on and the teacher wouldnt notice but we'd have to grin and bare it cus the teachers would think we were crazy. Obviously we didn't grin and bare it though we just slapped them round the faces. But yanow.

It's a bit like the kind of high-frequency noise you get from a CRT television.

I am so gonna use that to annoy people.  I will test it on some old people.  I can hear it and I'm 22

=\ I can barely hear it, and I'm 17 :P but I have very good hearing noneth- AH HA! turn the speakers up... and annoy everyone around me

That really really hurt my ears...

I can hear it, I'm young :D
But my mother cant.

Ah ha ha!  Cure wins todays "SNAP!"

Or, instead of using laser-guided kryptonite-powered space age technology, you could put the phone on vibrate.