You are a veritable textbook on Electroscopes! I have accumulated everything required to build one except the gold leaf, but upon reading your post, I find that I'm building it incorrectly, using the classic glass jar, rubber stopper, brass rod, and round brass drawer pull.
I had no idea that the gold leaf electroscopes were so sensitive! Responding to just a few hundred volts would make the instrument useless when probing near a static field of nearly a million volts!
Also, I'm unwilling to go to all the trouble with molten sulphur, a Faraday cage, delicate leaves, a conductive window, etc. Thankfully, I only have about $3 invested in the components for the old time electroscope, and rather than spending another $7.49 on the gold leaf, I'm just gonna order a unit from Science First. As pictured on their website, the instrument is in a cubical aluminum housing (Faraday Cage), with a square viewing window, and uses aluminum leaves with a spare pair included. Tell your search engine to go to "Science First".
I'll order this electroscope today. The product number is 10-045, and the price ois $19.20 plus shipping.
Ionized Atoms to you all...
- Wow. Lots of good info! For my purposes, something somewhat less
sensitive a gold leaf electroscope (and much less fragile) is what I need.
What I need are very cheap electroscopes I can build and give to kids
as young as kindergarten. Sensitive enough for the static from a
balloon to cause an indication or from a TV screen but tough enough to
have a reasonable chance of surviving being dropped a few times.
I'd wondered about the effects of nonconductive containers. I thought
I might try a thin coating of glycerin inside a clear plastic cup.
However, now I worry about the leakage in the untreated cup leaking
off charge. I wonder how insulative hot glue is?
Obviously what I'm attempting to build are not precision instruments.
A kind soul from the Mad Scientist list is mailing me some tinsel to
try. I've had bad luck with a homebrew aluminum foil electroscope, it
is almost impossible to avoid wrinkles and even the slightest stiffens
it too much so that even the 15 to 20KV from a TV screen doesn't cause
even a visible stirring. I could hang two separate pieces of aluminum
foil from a wire, but the first time it's dropped I can see them jamming.
I tried a strip of aluminuzed christmas wrapping paper but although it
responds to my TV screen, it appears to be entirely due to
nonconductive inductive effects.
I see there is a design using an almost balanced beam. Probably highly
robust and accurate, but way too much work required for my use. Unless
I can figure out a way to build them easily, or find something cheap
that I can adapt.