You will see lightning rods if you look closely at many tall buildings and other structures. Those lightning rods are there to protect the buildings from lightning strikes, but we don’t often get to see them in action.
We don’t see the benefits of lightning rods because they work at a time when lightning strikes and it happens so quickly we can’t see it.
However, your perception of lightning and lightning rods might change thanks to a couple of Brazilian scientists who slowed down images of a lightning strike. They used a camera that took 40,000 frames per second, allowing them to slow down time.
The first thing you will likely notice from the video is the direction of the lightning. When we see the bolt of lightning, it appears to be coming from the sky down, but the slow-motion video clearly shows it is coming from the buildings up.
This phenomenon is known as leaders, and they rise from the lightning rods to meet the thunderbolts in midair. Leaders happen any time lightning strikes. If lightning rods don’t exist, they will come off any object.
According to the New York Times, this can include humans. If you are standing where lightning strikes, the leader could discharge from your head or shoulders.
Perhaps the most interesting part of this is that not all leaders are connected with the bolt of lightning. There is enough charge in the leader to injure you, and you might not even get struck by lightning.
You can see multiple discharges coming off of the buildings in the area before the strike occurs. In the video, Saba speaks about how the image was taken on a summer evening in São José dos Campos. The charged thunderbolt was traveling at 370 km/s toward the ground.
It had reached the ground when the lightning rod started to work. As the negative charge was nearing the ground, positive charges extended upward from the lightning rods to connect with the downward strike.
In the final image, you see what happened “25-millionths of a second before the lightning hit one of the buildings.”
Lightning rods are made of aluminum or copper with wires connecting to the ground. They are put at the high points of construction for a reason.
Thunderbolts are going to hit certain buildings, but lightning rods offer an easier and safer way for the lightning to discharge to ground. It does so by offering a path of least resistance, and it protects the building and its contents in the process.
You also see the need to be thorough when installing lightning rods. In this video, the lightning rods protected the building, but lightning also struck an unprotected smokestack.
Saba said it was a flaw in the installation and the 30,000 amp discharge did “enormous damage.”
You can see it for yourself in this video: