> Ken said:
>
> >Tell your student that the jiggling of the scene is due to
> >mechanical vibration of the eyeball due to spread of the
> >mechanical action of the toothbrush through the skull.
> >
...then Tim said:
> But then why is it only some things that jiggle and not others? I get the
> jiggling when looking at LED clocks but not at LCD displays. The computer
> screen doesn't jiggle and most tv/sat signals don't jiggle. We don't hear
> any jiggling either so I doubt it is that sensitive (though I like the
> simplicity of the arguement!).
Well, we need a little more data, I think. Hey, Faith, does the display jiggle
when (a) you don't have the toothbrush (hereinafter, TB) in your mouth, or (b)
when the TB is running but you are not holding it, or (c) when the TB is
plugged into circuit in the house different from the one the clock is plugged
into?
A possibility is that the clock is -actually- flickering as the LED segments
are driven from some oscillator in its works. These -are- seven-segment
digital displays, aren't they? I think it is the case that those are
driven in rotation, but at a high enough frequency that we normally don't
see the flicker. I don't know for sure, but I have the impression that the
oscillator is not driven by the AC waveform...no can't be...LED's are DC.
Really speculatively, the additional load from the TB alters the juice (a
technical term) to the clock enough to slow it down below a CFF threshold.
A better guess (that's all any of us is doing, right?) is that there is an
interaction between the flicker of the LED's and the jiggle of the head as the
TB is used. An analog might be the pattern of multiple images one gets when you
wiggle a pencil in front of a TV screen.
...then again, maybe Ken's right after all.
Pat Cabe
**************************************************
Patrick Cabe, Ph.D.
Department of Psychology
University of North Carolina at Pembroke
One University Drive
Pembroke, NC 28372-1510
(910) 521-6630
[EMAIL PROTECTED]
