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Lightning Ground

  1. Aug 24, 2008 #1
    Hello, yes another GROUNDING question :)

    Can anyone tell me why lightning wants to travel to the Earth?

    and what happens to all that current that it carries after going into the Earth. Like what does the Earth do with it..

    are there positive ions that neutralizes everything or what?
  2. jcsd
  3. Aug 24, 2008 #2
    when the ionsphere carries an electric charge it takes on a negative charge. When the ionsphere takes on the negative charge it forces the negative charges in the ground downward so that the earth's positive charges move closer to the surface. when a path of least resistance is created to the ground the negative charges move to the earth and a return current of positve charges moves towards the clouds. By this the charges neutalize each other in the earth and the current dispates into the ground.
  4. Aug 25, 2008 #3
    so positive charges can create a current too?
    I thought the movement of electrons resulted in current... only..:s?
  5. Aug 25, 2008 #4
    That is true. When something is positively charged, it has a deficiency of electrons..that is, there are not enough electrons to keep the object neutral (in charge). When lightning strikes, electrons are flowing from the negatively charged area to the less-negatively charged area thus neutralizing the charge of both.
  6. Aug 25, 2008 #5
    ohh very nice, thanks!

    is that the idea of how current actually works though?

    for example is that how the EMF is produced?
  7. Aug 25, 2008 #6


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    There are several misconceptions here.

    1) The ionosphere is not involved in lightning.
    2) Lightning can travel from ground to cloud, cloud to ground, or cloud to cloud.
    3) Lightning is the neutralization of a difference in charge between the ground and cloud, or between two clouds.
    4) The enormous voltages involved are capable of ionizing gas molecules. The ionized gas provides a pathway for the conduction of current.
    5) These ionized pathways, called streamers, extend upward from the ground, and downward from the cloud, growing in length as the charges accumulate.
    6) When two streamers touch, a complete pathway is formed, and a very brief but intense current of electrons flows. This is the bolt of lightning.

    - Warren
  8. Aug 25, 2008 #7
    ...and there is the mysterious "ball lightning". I have seen one occurence of this and several videos. The one I actually witnessed went along an overhead span of 13.8kV, down one pole, back up the pole, back along the first span and then disappeared leaving no clear evidence of damage. It was about the size of a large beach ball. (about 3 feet in diameter)

    Some videos of ball lightning are available on the net...via google.

    Here http://www.sky-chaser.com/schlight.htm is a fairly good explanation of lightning. (Not that the above is insufficient...'tis just different.)
    Last edited: Aug 25, 2008
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