Tuesday, August 5, 2008

A Bolt From the Blue

Monsoon season is here, finally. This June wasn’t as hot, or as dry, as it historically has been, but still any time the temperature is over 100 degrees and the humidity less than 10%, the relief provided by summer thunderstorms is welcomed. Monsoon means much needed rain, a cooling breeze, and lightning.

At any given time there are 2000 thunderstorms in progress around the world releasing 100 lightning bolts every second. A lightning bolt unleashes 20 million volts of electricity and heats the air around it to 50 thousand degrees, that’s five times hotter than the surface temperature of the sun. Every year there are a hundred or so lightning related deaths, several hundred more people injured, and millions of dollars of property damage just in the United Stated along.

Exactly what lightning is and how it’s caused has been a mystery for thousands of years. Ben Franklin with his infamous kite was the first to prove that lightning is electrical. Of course if old Ben was so terrifically smart, why was he out in the middle of a storm holding on to a metal wire attached to a kite?

Lightning is caused by the separation of negative and positive charges in different regions of a cloud. Ice particles in the cloud grow, break apart and collide. The smaller ice particles acquire a more positive charge and the larger particles a negative charge. The smaller particles are lighter and have a tendency to be carried up into the higher regions of the cloud. The larger particles are heavier and accumulate in the lower regions of the cloud. When the electrical potential (the difference between the negative and positive charges) within the cloud and between the cloud and the ground, is great enough, the electrical resistance in the atmosphere breaks down and the flash begins. Lightning is the electrical discharge, think of it as Mother Nature restoring order.

Thunder is produced by the heating of the air along the electrical current and occurs simultaneously with the lightning flash. Sound travels much slower than light, so the farther away the lightning is, the longer the delay between the lightning flash and the thunder. You can guess roughly how far away a strike is by counting the seconds between when the flash is seen and when the thunder is heard. For every five seconds counted, the lightning is a mile away. If you see the lightning at the same time you hear the thunder, odds are: you’re toast.

Worst places in Fountain Hills to watch a thunderstorm:

Under a tree at McDowell Park

On the tenth tee at Eagle Mountain

(any tee, green, fairway or rough on any golf course, for that matter.)

In a swimming pool

Sitting on the scrap metal horse at The Fountains Park

In other words if you’re caught in a thunderstorm, stay away from tall trees. Usually lightning will hit the tallest object and if you’re standing under it, the charge can jump from the tree to you. If you’re in an open space you are the tallest object, so crouch low, lay flat on the ground, or get to your car or a building as quickly as possible. Water is a great conductor of electricity, stay away from being in the water or on it during thunderstorms. There’s a reason throwing a hair dryer into a bathtub is used in cheesy movies to murder someone. And finally don’t pull a Ben Franklin – what was he thinking – stay away from metal objects.

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