1. Lightning

2. Lightning Polarization of + and – charges within a storm cloud by frictional charging and freezing. + charges carried to upper portions of cloud and – portions gravitate to bottom of clouds. –Electric field from cloud induces movement of electrons upon Earth Buildings, trees and people can experience a build up of static charge as electrons are repelled by the cloud’s bottom.

3. Anatomy of Lightning As static charge buildup increases, the electric field becomes stronger Ionization of surrounding air makes it more conductive Begins with development of a step leader. Why zigzag? Induces a strong positive charge on earth surface. This charge begins migrating upward (streamer) through buildings, trees and people into the air. When step leader meets streamer, a complete conductive pathway is mapped out and lightning begins.

4. Lightning Rods Pointed metal pole which extends upward above the building, is attached by a copper cable to a grounding rod buried in the Earth below. “leaks off” excess charges in the atmosphere, thus reducing the likelihood of a sudden and explosive discharge.

5. Myths about Lightning Never strikes the same place twice Only strikes very tall objects Does not strike water Could be used as a power source Rubber shoes or boots insulate and protect against a lightning strike A metal vehicle is safe because of rubber tires “Heat lightning” is a strange phenomenon caused by hot water or occurs after very hot summer days and poses no threat. Lightning victims are electrified

6. Facts about Lightning The average flash could light a 100-Watt light bulb for more than three months Chances of being struck are estimated to be 1 in 600,000 Temperature of a flash is 5x hotter than sun’s surface Can travel over and through the Earth’s surface ~20 million cloud to ground lightning strikes occur in the US per year ~2,000 thunderstorms active throughout the world at any given time, producing more than 100 flashes/second ~26,400 lightning-induced fires/year in the US 80% of livestock deaths attributed to lightning strikes Second largest storm killer in the US (#1 floods) The Guinness Book of World Records lists Roy Sullivan of Virginia as the human being struck by lightning the most times: seven. This is one record you don't want to beat!