An electroscope is a tool used to demonstrate the effects of electric charges, conduction, and induction. For example, with a metal electroscope, by holding a charged rod near the bulb at the top, the opposite charges are attracted to the top and the like charges are repelled to the vanes at the bottom, causing them to tilt and separate. If you ground the scope while still holding the charged rod near, the like charges are repelled to the ground, leaving only opposite charges on the metal. If the rod is then removed, the opposite charges disperse throughout the vanes and cause them to tilt until the metal is grounded again and like charges are allowed to flow back into the scope. This phenomenon is known as induction, and is one of a few ways to cause the electroscope to demonstrate a physical property.
I printed this electroscope twice: The first time was with ProtoPasta magnetic iron filament (greyish) and used a Z-pause to achieve the color difference in the base. Magnetic iron will not hold a charge, but you can instead use strong magnets like neodymiums to manipulate the vanes into moving. The second time was with conductive PLA (blackish) and used dual extrusion to achieve the color difference in the base. I have yet to test if the conductive filament will hold a charge well.
100% for the smallest piece, 20% everywhere else
For the color difference on the base, either use a manual Z-pause or use the included dual extrusion files.
Be sure to lightly sand the pegs on the smallest piece and the holes on the medium-sized piece to allow for low-friction rotations of the vane. Carefully rotate the smallest piece to slot it into the holes. Apply a touch of glue to either rectangular piece at the top of the base piece and glue the medium-sized piece into place.