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Re: Leaking 'Static Electricity'



Thanks, Chuck, but I'm still a bit confused.

If I understand you, my VDG discharges along its column, not through the
air. That is a plausable explanation to me. Does this mean that the
*humidity* supplies the "solution" to allow the junk on the column to start
an ionic conducting path?

Certainly, I believe that oil and grime (usually from hands which picked up
the VDG by the column) provides a multi-megohm resistance path from the
sphere to the base (via the small cracks in the column which result from
static produced ozone interacting with the plastic of the column). I have
been able to dramatically improve performance by cleaning the column with
alcohol, and allowing the alcohol to evaporate.

I also know that on a high humidity day, that static electricity demos
don't work. Some "crisp" weather parts of the country never have this
problem. I even keep all electrostatic demos in a dry cabinet with light
bulbs burning 24 hours a day to insure their dryness.

I realize that water, as a polar molecule, is not generally a good
conductor (unless "dirty", and thus ionic), although it is an excellent
dielectric when clean. Clearly, suggesting that warm, moist air ("clean
water carrying" air) is a good conductor makes little sense to me, but I
don't have a better explanation.

My confusion is that if I run a (cleaned column) VDG, or run a comb through
my hair, I get good results when the air is dry. If I open the door on a
humid day, both of these "clean" sources cease to produce static charge
separation.

So...I'm all ears for a "clean" explanation. Karl

Regarding the humidity leaking charge explanation: What is the accepted
mechanism? I know my electrostatics demos don't work when the humidity is
high, so I am guilty of saying that the charge leaks off....Karl


Nothing wrong with leaking charges. It just leaks along slightly conductive
SURFACES (not thru thge air (unless there is an unusually high density of
ions around.)

Anti-static dryer sheets seem to leave a SMALL amount of hygroscopic
'chemical' on the fabric which allows enough conductivity to discharge the
fibers.

It's no accident that stressed Chuck Britton
spelled backwards is desserts. britton@odie.ncssm.edu

Dr. Karl I. Trappe Desk Phone: (512) 471-4152
Physics Dept, Mail Stop C-1600 Demo Office: (512) 471-5411
The University of Texas at Austin Home Phone: (512) 264-1616
Austin, Texas 78712-1081