Humidity is _very_ important. If you can control it, it makes a big
difference. I like to do this demonstration on cold days. Being on the
fall line -- the break between the coastal plain and the foothills of
Appalachia -- our humidity is highly variable. I have to watch the weather
to do a successful Electrostatic experiment. Cold dry days permit a greater
charge buildup and a more spectacular discharge. I also have to remember to
turn off the lights so the sparks show up better.
Tom Russ
The Brookstone School, Inc
Columbus, GA