History

• Benjamin Franklin sought to prove that lightning was a form of electricity.Gentleman writing on desk image by patrimonio designs from Fotolia.com
  
  Benjamin Franklin began his experiments with electricity in 1746 after hearing of other scientists' work in the field. According to information found in the archives of The Franklin Institute, Franklin was the first person to use the terms "positive" and "negative" instead of "vitreous" and "resinous," the popular electrical terms of his time. While performing experiments with electricity on homemade machines, Franklin first began to believe that electricity and lightning had many similarities, such as color, a crooked direction and a crackling noise. While there were other scientists with similar beliefs, it was Franklin who first decided to prove it. Only a few years later in 1750, he also began to think of ways to protect people and buildings from lightning, and thus came the idea for a lightning rod.
  
  

More History

• Franklin's famous experiment tried to attract lightning to a church steeple.Church Steeple image by Ktulu from Fotolia.com
  
  While almost everyone knows of Franklin's famous experiment with lightning and a key, not everyone knows that Franklin had noticed that a "sharp iron needle would conduct electricity away from a charged metal sphere" two years prior to that. As a result of his observations, he believed it would be possible to conduct lightning away from buildings and into the earth by means of an elevated iron rod. In June 1752, a key attached to the iron steeple on top of Christ's Church in Philadelphia proved exactly that.
  
  

How Lightning Rods Work

• Lightning travels from clouds to the earth and then back to the clouds.lightning strikes image by drseward from Fotolia.com
  
  Although lightning is nothing more than a buildup of static electricity within clouds, between clouds, or between the earth and one or more clouds, that buildup can be dangerous when it discharges. A positive charge seems to develop more at the tops of the clouds while the negative charge races toward the earth, ionizing part of the air around it as it travels. As a rule, that negative charge will hit a tall, exposed object on earth since that object shortens its path to the ground. The charge will then return to the clouds because it is attracted to the positive charge there. A lightning rod works by allowing that negative charge to enter or leave the earth without damage to non-conducting materials.
  
  

Lightning Rods Then and Now

• Lightning rods of today work on the same principal as those created by Franklin. It is interesting to note that while Franklin preferred rods with a sharply pointed top because he believed those were more effective, the King of England believed blunt rods worked best. The English actually felt this was just one more instance of rebellion by the colonies. While there are a variety of lightning rods available today, all seem to be effective, according to the National Fire Protection Association's code NFPA 780. However, according to an article published in USA Today in 2000, scientific testing seems to favor blunt rods.
  
  

A Final Word

• While lightning rods have proved effective in directing lightning away from buildings and other structures, it will not keep lightning from striking. In addition, a direct hit to a building or to a nearby power line that results in a power surge can still cause much damage.