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Q & A: earth and lightning

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Most recent answer: 10/22/2007
Q:
we consider that earth is good conductor of electricity ,but we also saing that lightning occurs due to static charges developed due to relative motion of earth & clouds. Wheather earth is conducting or insulating ,as it support both fundas ?
- Amol shivaji kochale (age 23)
shahada, maharashtra, INDIA
A:
I think that what you're getting at here is that a good conductor should drain away static charge. However, if the charge separation is between the Earth on one hand and the clouds on the other, there's no way charges can flow through the Earth to get to the clouds, even if the Earth were made of copper. The charge has to flow through the air, which at least starts off as a very poor conductor. Only when it starts to break down, with the electrons getting stripped off some molecules, does it become a good conductor. That's why the lightning occurs in sudden bursts, rather than just by a slow steady current flow.

I hope this answers your question. If not, please write back.

Mike W

(published on 10/22/2007)

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