of electric toothbrushes wobbles and monitors

[GreeFieldSite]

Here's an interesting effect.

When I was cleaning my teeth with an electic toothbrush and looked at my computer monitor (CRT) the picture wobbled. What is interesting is that neither the rest of the room nor my LCD monitor sitting beside it showed the same effect.

It seemed to work best when I was a fair way away from the monitors (20 feet say)

Any ideas?

[Mangetout]

A similar effect can be had by watching the same monitor while chewing something crunchy.

What's happening is that your eyes are being moved abour a little by the vibration, because this vibration is reasonably fast in comparison to the scan rate of the monitor, you're seeing part of the screen refreshed, then the next bit with your eye in a different position, the next bit with your eye moved yet again - the result is that the image projected on your retina by the light from the screen scans is broken up.

[gcarroll]

Here's an interesting effect.

When I was cleaning my teeth with an electic toothbrush and looked at my computer monitor (CRT) the picture wobbled. What is interesting is that neither the rest of the room nor my LCD monitor sitting beside it showed the same effect.

It seemed to work best when I was a fair way away from the monitors (20 feet say)

Any ideas?

A product of phosphore persistance, refresh rate, and vibration. You moved (vibrated) before the spot lighted by the electron beam completed one cycle of the screen.

[Jurph]

I first noticed this phenomenon shortly after getting to college. I was working on a paper and listening to music, and while humming along with a song's bass part, the small vibrations my humming created in my head had the same effect.

Interesting side effect: if you know the note you're humming and can convert it to Hz (http://www.hypermaths.org/quadibloc/other/musint.htm), you can determine (by watching the monitor wobble slow down to near-nil) what the monitor's refresh rate is. If you know the monitor's refresh rate you can work back to find the note you're humming (less reliable).

Non-bass singers can blow raspberries of varying intensity to observe this effect or use a multi-speed massager pressed against the chin or forehead.

[Small Clanger]

I'm wondering if some of you are barking up the wrong tree. To me it sounds more like magnetic interference. The motor in the toothbrush is generating a varying magnetic field which inteferes with the electron beam in the CRT, but doesn't effect the LCD screen.

I've seen the same thing happen when someone uses a mobile phone near a monitor. It looks like you've hit the de-gauss button.

[Small Clanger]

Re-read the OP. Scratch all that. Won't work from 20 feet away unless you've got some super-powerfull death ray style toothbrush there. Try changing the screen refresh rate how does that effect the wobbling?

[Mangetout]

I'm wondering if some of you are barking up the wrong tree. To me it sounds more like magnetic interference. The motor in the toothbrush is generating a varying magnetic field which inteferes with the electron beam in the CRT, but doesn't effect the LCD screen.

I've seen the same thing happen when someone uses a mobile phone near a monitor. It looks like you've hit the de-gauss button.I've seen this too; chiefly with desk fans next to CRT monitors, but I'm certain that this isn't the case for GreeFieldSite - I'm going to wager that the effect ceases when he/she simply removes the toothbrush from the mouth, without turning it off.

If you've never experienced the phenomenon we're describing, get some hard candy (Like barley sugar), turn the refresh rate on your CRT monitor down to the lowest setting and watch from ten yards away while crunching the barley sugar in your mouth.

[Futile Gesture]

I'm wondering if some of you are barking up the wrong tree. To me it sounds more like magnetic interference. It's vibrations on your eye combined with the refresh on the monitor. Definitely. It's a well known effect.

[jsc1953]

I saw the same effect recently while brushing my teeth and looking at a digital clock (from across the room -- about 20 ft away). I was certain there was something happening with the clock, as nothing else in my vision was affected; until I experimented by taking the toothbrush out of my mouth.

Trippy.

[Chelonia mydas]

better yet, go to a computer store, walk over to the monitors and roll your r's...ooooOOOOOooooo

The Turtle Moves