Ways to minimize extraneous interactions in an amateur Cavendish apparatus?

I have decided to recreate a Cavendish apparatus for my high school's senior capstone program. My ideal goal is to calculate G, however I understand that the accuracy of an amateur device would probably preclude accurate calculation. If need be I will simply rebrand it as a way to observe small scale gravitation.

That being said, I would like to do everything I can to isolate gravitation from any other forces. I'm still in the design phase, but I was hoping to get a little insight from some more experienced physicists and engineers. Keep in mind that my experience is limited to BC Calculus and AP Physics, with only minimal knowledge of E/M; what little E/M I know was self-taught for the SAT subject test.

From what I have read, both on reddit and elsewhere, it seems that every amateur Cavendish apparatus is criticized for ignoring similar factors, namely the following:

1. Electrostatic interactions between the large and small masses
2. Air currents
3. Any ambient electromagnetic field interactions

Most of my questions stem from number 1, which I have seen pointed out most often. Given my limited experience, I don't have a good grasp of the nature of minute electrostatic charges, how they are acquired, and how they can be avoided/discharged. Much of the difficulty of this experiment is that interactions ignored by many textbooks become quite problematic when dealing with gravitation, and so it has been difficult to answer my questions through research alone.

For my masses, I am using spherical lead fishing weights. I understand that most triboelectric series place lead somewhere on the positive end of the spectrum, which is to say it can acquire a static charge. I am considering also encasing the apparatus in a box constructed from plywood, with one side of Plexiglas for observation, in order to prevent air current disturbances. Both materials can acquire charges. My questions are:

• Outside of any sort of friction or contact, would it be possible for the lead, wood, or Plexiglass to acquire any static charge? If so, what would be the most efficient way to remove this charge?
• Would it be possible for even a minute electrostatic attraction to develop between two objects of the same material (the lead weights)?
• If so, would it be sufficient to "ground" the two masses to one another in order to neutralize this attraction? Or would they have to be grounded to a larger body e.g. the earth?

I apologize for what probably seems riddled with layman misconceptions, but any input would be much appreciated. Thank you in advance!

Submitted January 30, 2016 at 10:09PM by TheNefariousNerd http://ift.tt/20f985r