How do cell phones vibrate?
Dave
State College, Pennsylvania
Dear Dave:
In the same way that we can only dimly grasp how airplanes fly and boats float, cell phones baffle us. Of course, our ignorance doesn't stop us from shouting into them each and every day. And since most of us use cell phones, the least we can do is set them to vibrate rather than subject folks to obnoxious ringtones.

To explain how the vibrations happen, How Stuff Works performed an autopsy on one ill-fated Tickle Me Elmo. The doll uses a shaking technology that's exactly the same as a cell phone's, though considerably larger. (Those queasy about Muppet innards should stop reading here.)

Here's what they found: A flywheel motor with a weight is attached to one side. When the motor turns, the weight throws it off balance and creates a wobble. That wobble causes the whole device, be it a friendly plush monster or a sleek cell phone, to jiggle.

Now, we want to ask you something: Did you ask this because you've tried to answer your phone when it vibrates, only to find it's not actually moving (or even on)? If so, you may have had close encounters with a new phenomenon -- the phantom cell phone vibration. Perhaps you're hoping for a call just a little too fervently. Perhaps your muscles are twitching. To be honest, we're not sure. But to be on the safe side, maybe it's time you call an exorcist (on a landline, of course).