Lightning Rod


History of the Lightning Rod

By 1750 Benjamin Franklin wanted to protect people and buildings from lightning. This is how he came up with the idea of the lightning rod. He described the rod to people as an 8-10 foot iron rod that will be mounted on top of buildings. 2 years before is kite experiment,he observed that an iron needle could conduct electricity away from a charged metal sphere. He thought lightning might be avoided by using an iron rod elevated on a building that is grounded. This is how he thought of the idea of a lightning rod. He wrote "the electrical fire would, I think, would be drawn out of a cloud silently, before it could come near enough to strike" (Benjamin Franklin) In June of 1752, Franklin travelled to Philadelphia to conduct his experiment. He used the steeple of a church to act as a lightning rod.He became impatient when lightning didn't strike and decided he could use a kite, a key and a piece of string to conduct the same experiment. The lightning struck the key and then he knew lightning was a form of electricity. He also discovered that it could travel through the lightning. One of Benjamin Franklin's theory was lightning could be prevented by using a large iron rod that will conduct the electricity to the ground. Therefore the lightning would be grounded and would not injure anyone. Once he determined that the lightning rod would be successful, it became a success. People all over the towns had put lightning rods on their homes and business's and there was even a lightning rod on top of the State House.

Lightning Rod Invented!

Tuesday, July 18th 1752 at 9pm

Philadelphia, PA, USA

Philadelphia, PA

Benjamin Franklin has proved lightning is electricity and has figured out a way to protect people and buildings

How do Electrostatics come into play?

Lightning is a large discharge of static electricity. It is no difference from you getting a shock from touching a metal doorknob. Lightning will prefer to get on anything that it can such as a human, a house or a tree. Usually the tallest thing around since lightning is coming from the sky. Lightning wants to take the path with the least amount of resistance. The lightning rod is a conductor. When lightning strikes it allows the electrons to move from the cloud,to the rod and into the ground. Lightning rods do not attract the lightning however they do divert the strike into the ground. The lightning rod usually has a copper wire on the top which is one of the best conductors around. Since it is such a great conductor, it allows the lightning to travel down the rod and into the ground with the least amount of resistance. Many people are mistaken about lightning rods. They think that lightning rods attract lightning to it however it just creates a path for the lightning with the least amount of resistance. Lightning rods are on top of the building that is nailed into the ground by a grounding pin. The cloud is negatively charged. We know this because when we ground an object the electrons travel to the ground and the ground is positively charged. Opposite charges attract, so the lightning will want to travel down. However this is where the Lightning Rod comes into play.The top of cloud is positively charged and the bottom is negatively charged. This is called induced charge separation. The soil becomes polarized because soil is very conductive. The Electrons from the lightning will hit the lightning rod, and since it is a conductor they will travel into the ground. This neutralizes Then the electrons are pushed away from the grounding pin. As a result the lightning rod becomes positively charged.

This is just the basics of the lightning rod. For more information watch the video below.

Lightning Rods Part 1

What is the purpose of a lightning rod?

The purpose of a lightning rod is to protect buildings from lightning strikes. It is very simple. It is a large metal rod (so it can conduct the electrons to the ground) which is about 2cm in diameter. The purpose of lightning rods are misunderstood in many cases. Most people think that it is used to attract the lightning however lightning rods provide a pathway to the ground which has very little resistanceThe lightning rod may have very low resistance but it can conduct mass amounts of electrical currents through it! If lightning strikes the rod it carries the dangerous strike through the lightning rod and grounds it safely. In conclusion, lightning rods do not attract lighting but they allow a safe option and a low resistance path for lightning. The lightning travels down the conductive metal into the ground where the strike is pushed away into the ground and is no longer a threat.

Is It The Only Way To Protect Against Lightning?

No, Lightning Rods are not the only method of protecting yourself, or your home from lightning. It is however the most commonly used, most efficient and least expensive. Other methods would be towers,Rotors or cables. They all work the same as a lightning rod but are much more complex and expensive. The towers are better if you are trying to protect a large area of land, or an open space. The lightning will likely go to the tallest thing there which will be the lightning tower.

Lightning Rod at work!

What a Lightning Rod Looks Like


"How Lightning Works, Lightning Rods" How Stuff Works N.D. Web. February 17 2013

Adams, Cecil "Do Lightning Rods Really Work?" The Straight Dope. August 24 2001, February 17 2013

"Lightning Rods" The Idea Finder N.D, February 17 2013

"Lightning" Physics Classroom. N.D. February 17 2013

"Lightning Rods part 1", August 15, February 17 2013