What is lightning? ```Name: N/A Status: N/A Age: N/A Location: N/A Country: N/A Date: N/A ``` Question: Could you explain the physical characteristics of lightning as it pertains to physics? Replies: Lightning is a discharge of a large electrostatic charge that builds up on clouds near the surface of the earth during atmospheric disturbances such a thunderstorms (duh!). According to Frederick Trinklein (Modern Physics textbook for High Schools) a typical discharge from a lightning bolt is a coulomb of charge. This is rather substantial. Given that the electrical potential that builds up between the cloud and the ground is usually estimated in the high megavolt range, the energy transferred here is remarkable. Obviously if a one megavolt bolt hits something delivering a coulomb of charge in the process a megajoule of energy is transferred. Also given that this whole event takes place in a fraction of a second the power dissipated is equally remarkable. Note: this meagvolt bolt I speak of is purely hypothetical for the sake of example. As I recall l last year National Geographic had an excellent non-technical article on l lightning. You might scrounge around for that -- 93 or 94,I think. By the way, the conventional theory is that the electrostatic charge builds up as a result of frictional action between the billions of water droplets in the cloud. This is however only theory. The system is so complex that I am not sure there are many who are prepared to say exactly how lightning potentials form. This is a bit of a "hand w waving" sort of explanation, but I hope it will get you going a bit. Thanks for your time. Nick P. Drozdoff Click here to return to the Physics Archives

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