Lightning is dangerous. Everyone knows that. But what I’ve seen happen recently on the soccer fields makes me realize we don’t have the fear of lightning that we should.
In this article I want to share with you some of the knowledge I gained as an electrical engineer.
The first question I have for you is why are you safe in a car if lightning strikes your car?
Many of you will say it’s the rubber tires. The way I had this explained to me, is the lightning just went 1000’s of feet through the air. Why would an inch of rubber matter at all?
It’s not the tires that save you. It’s the fact that you are surrounded by metal and that creates a Faraday cage. Here’s how it works. Voltage doesn’t kill, current does. You see birds sitting on power lines all the time. When they’re flying, they’re at zero volts and when they land on the power line they’re instantly at 10,000 volts or whatever the line voltage happens to be. But no current traveled through the bird, hence he doesn’t feel a thing.
Now in the car, the lightning strikes your car and instantly your car goes from zero to 10,000 volts or whatever the voltage may be. But your entire car is at the same voltage because it’s made of metal. If you happen to be touching a piece of metal in the car that’s attached to the frame, you too will be like the bird. You’ll feel nothing except for the kaboom of the bolt. If you’re not touching something attached to the frame, nothing happens either. If you’re in a convertible, you’re in trouble however because you’re not surrounded by metal.
Your microwave is a Faraday cage as well. The radio waves that cook your food stay inside the enclosed container and don’t cook you as you’re looking in. You’ll notice the window of a microwave has a mesh inlay made of metal with holes large enough to see through. This along with the rest of the metal frame is enough to keep the radio waves trapped inside.
Another example that is interesting is years ago when our plumbing was made of metal piping instead of PVC there was a problem that would happen occasionally. Remember when houses had lightning rods? Those rods were connected to ground with a thick wire running down alongside the house. If that wire happened to run down alongside the bathroom close to the bathtub and there happened to be a person in the bathtub at the time of the lightning strike the person in the tub could die. What would happen is the lightning pulse would charge down the outside wire, arc over to the person in the bathtub and then to ground along the metal piping. The person in the bathtub would be electrocuted because of the high current flow through their body.
So what they started doing is, get this, they’d attach an additional wire from the lightning rod wire to the metal piping of the bathtub so no current could flow through the person in the bathtub. Yes the person would instantly be charged to high voltages, but they wouldn’t feel a thing just like the bird on the wire.
Most people think of lightning as going from sky to ground in somewhat of a straight line, but lightning can go much more sideways horizontal to the ground. People have been hit by lightning from many miles away from the storm that caused the lightning. Here’s the rule of thumb. If you hear thunder, take cover.
Recently during a soccer event, this advise was not recognized in the least. It drove me crazy. There were large thunderstorm cells all around the soccer field, but it wasn’t raining yet so the game kept going. It wasn’t until it started raining that people took shelter. I wasn’t there, but my wife was telling me this as it happened. The coach was mad at her for leaving the game before it was done.
Also, never take cover next to a tree during a thunderstorm. Lightning can strike the tree and as the current travels down the trunk of the tree, it can arc over to you and find it’s way to ground. If it doesn’t kill you, it will severely injure you. So please be careful and take cover.
Lightning is one of the leading causes of weather related death and injury in the US. You can be struck by lightning when the center of the thunderstorm is 10 miles away and there are blue skies overhead.
If only we could harness that power like in “Back To The Future”. As the younger Dr. Emmett Brown said, “1.21 Gigiwatts. Great Scott”Share