Benjamin Franklin may not have discovered electricity with a kite, but he did propose that lightning could be drawn through a metal rod, resulting in electricity. The experiment was performed with great success in Paris in May 1752, and so the concept of a lightning rod was born. But how does a lightning rod actually work?
The Path of Least Resistance Is not Attractive
Lightning rods aren't that big. They are about an inch or less in diameter and are a few inches to about 12 feet in length depending on your residence or commercial building. People often think that lightning rods attract lightning - but this is false.
Lightning rods don't attract lightning. They offer a path of least resistance that dissipates the lightning through the ground, much like a ground wire in your home does. To understand how a lightning rod works, you need to understand a few facts about lightning itself.
Lightning Is about Balancing Charges
Lightning occurs when colliding particles in the air create an electrical imbalance between storm clouds and the ground. These charges are negative at the bottom of the storm clouds and become positive when they reach the earth. The earth must maintain balance, or nature will balance it for us, which is why nature creates an electrical bridge between the negative and positive charges.
This bridge between charges creates lightning, and it can be dangerous should we neglect to find shelter. A single lightning bolt carries up to one billion volts of electricity and can strike a person from 10 miles away. This is why when you hear thunder, meteorologists tell you to find shelter immediately - even if the sky is blue.
For example, consider a golfer ignoring thunder and lightning on the golf course. He's on the green and wants to get a last chance at par. The pole that designates the hole is taller than the golfer and therefore acts as a rod for lightning. Should lightning strike the pole, or his golf club as he swings, or even a nearby tree, that lightning bolt will race through the "rod" as the electricity runs through it, scattering along the ground.
This is why many golfers, high school soccer players, and baseball players are often struck by lightning. not literally by the bolt, but through the ground that they are standing on. That ensuing path of least resistance can still hurt or kill you.
How Does the Path of Least Resistance Work?
Here's the science behind why lightning rods work and why they are important in keeping you safe.
Negatively charged cloud-to-ground lightning meets a positively charged object on the ground - in this case, the aforementioned lightning rod.
The lightning rod didn't attract the lightning, it met up with the positive charge "streaming" up from the rod. They connect at about 200 million miles per hour. Electricity is transferred to the rod and routed by the lightning rod system to - and harmlessly through - the ground.
Should a lightning bolt originate from the top of a storm cloud instead of the bottom of a storm cloud, then it is called a positively charged lightning bolt. As dangerous as the negatively-charged lightning bolts are, the positive bolts are even more so because they reverse the flow of charges and cause more destructive force. These are the lightning bolts that strike out of a clear blue sky from 10 miles away.
According to the National Geographic, you have about a 1 in 5,000 chance of being struck by lightning in your lifetime here in the United States. About 2,000 people are killed each year from lightning strikes worldwide. Even so, 90 percent of those struck by lightning survive.
Some people feel a lightning charge while using their plumbing even if their building is grounded by a lightning rod protection system. This means when your parents said not to take a bath or use a landline phone during a storm, they were right. To protect your home and yourself from lightning, talk with our staff at Michigan Lightning Protection about installing a lightning rod.