Charged metal ball wrapped in rubber or other insulator

In summary, a metal electric conducting ball the size of an average snowball with a charge of 0.1 Coulombs will not discharge unless it is connected to a conductor or touched by something else. If it is wrapped in an electrical insulator and set on a wooden table, it may discharge naturally through the air after a long time. In a vacuum environment, the charged ball will not discharge unless there is something external that allows the charge to dissipate or be cancelled. However, there are many external factors that can influence the ball, so the duration of the charge is uncertain.
  • #1
If I have a metal electric conducting ball the size of an average snowball (Happy Holidays) and give it a charge of say 0.1 Coulombs and set it on a wooden table, will it ever discharge if not touched by anything else? If so, if it is wrapped in an electrical insulator, will it ever discharge within in the same scenario? If so, if the ball was hovering in a vacuum environment will it ever discharge?
 
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  • #2
It will not discharge unless it is touched by a conductor connected to ground. Otherwise, the charges within the material that the ball is adjacent to will be drawn to the surface closest to the ball.
 
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  • #3
So charged metal ball touching a wooden table will never discharge? Even after a long time like a year?
 
  • #4
If you mean never as in forever, that is an exaggeration. In theory, it should not. Although, I would be somewhat confident that it would discharge naturally through the air, rather than the wood, after a long time.
 
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  • #5
osilmag said:
If you mean never as in forever, that is an exaggeration. In theory, it should not. Although, I would be somewhat confident that it would discharge naturally through the air, rather than the wood, after a long time.
I see. What if the ball was floating in a vacuum? Would it ever discharge? Can electrons jump within a vacuum or would that require an absurdly high amount of charge
 
  • #6
PhDnotForMe said:
So charged metal ball touching a wooden table will never discharge? Even after a long time like a year?
Presumably there will be ions in the ambient air. What do you think might happen?
PhDnotForMe said:
I see. What if the ball was floating in a vacuum? Would it ever discharge? Can electrons jump within a vacuum or would that require an absurdly high amount of charge
Depends upon what you specify as "vacuum". If it's simply a region of space within our solar system, remember that the solar wind which fills that space has many charged particles.
 
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  • #7
gneill said:
If it's simply a region of space within our solar system, remember that the solar wind which fills that space has many charged particles.
If it is a man made vacuum on Earth in my living room, will the charged object inside ever discharge?
 
  • #8
PhDnotForMe said:
If it is a man made vacuum on Earth in my living room, will the charged object inside ever discharge?
I think that there would be a lot to investigate about how you isolate the charged object. No insulator made of real material is perfect; The existence of gravity means you'll need to support the object somehow. That and cosmic rays will still penetrate any container you can reasonably construct in your living room, so yeah, it'll very much likely discharge given sufficient time.
 
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  • #9
PhDnotForMe said:
If so, if the ball was hovering in a vacuum environment will it ever discharge?
Unless there is something external that allows the charge to dissipate or be cancelled, the charge will last indefinitely. I think that was your question.

However, there is considerable doubt about that "unless" part. There are many external things to influence the ball both on Earth and in space, and forever is a very long time. That is why the answer is more than a simple yes or no.
 
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