How Do Lightning Rods Work?
Do they attract lightning? asks a reader. Like the cartoon images of (a fried) Ben Franklin and his key-dangling kite, lightning rods seem like they must be a magnet for lightning. But the rods do protect buildings; just ask the insurance industry, which began giving discounts for homes with lightning protection in the 1920s. Lightning rods bristle everywhere from Kansas farmhouses to the Empire State Building to the White House. While its main occupant is always a lightning rod for political critics, the White House itself had its first rods installed in July 1910 – one on each of 12 chimneys. By 1930, Time magazine had declared the booming lightning-rod business “depression-proof.” It was almost 200 years earlier that Benjamin Franklin – interested especially in electricity – came up with the idea. He suggested houses and ships could be protected from lightning if they had a series of iron rods with their bases sunk into the ground or water.
The suggestions given ahead of me are a popular but untrue. Lightning rods are sometimes hit by lightning, but their main purpose is to bleed charge from the ground up thru the point of the rod. Clouds have charge from various sources in the cloud. Small pieces of sand blowing together and other various things. All this charge gets stored up in the clouds. When enough charge builds and has nowhere else to go, the path of least resistance to the ground is where the charge dissipates. The actual mechanism is complicated, and there are what are called leaders which travel from the ground UP, and this sets off a series of events leading to the actual discharge. Anyway……the clouds and the ground act like a giant capacitor in essence. The points on the lightning rods are areas of extremely high electric fields. The points are placed on them on purpose and for this reason. This ensures that charge will bleed off AT the points of the rods. The charges that bleed off then end up mixing with
This website describes common lightning protection systems, certification, installation, and lightning protection system inspection. We provide information about lightning strikes, lightning hazards, related equipment, sources of lightning protection system installers, and lightning strike risk assessment © Copyright 2009 Daniel Friedman, All Rights Reserved. Information Accuracy & Bias Pledge is at below-left.
Lightning is caused by electrical charges that build up in the clouds during a thunderstorm, then erupt in a bolt of electricity that reaches between two clouds, or between the clouds and the earth. When a lightning bolt streaks between clouds and the earth, it usually reaches the ground by first striking a tall object, such as
