Faraday Cages: Are We Safe in Our Cars During a Lightning Storm?
EducationFaraday Cages: Are We Safe in Our Cars During a Lightning Storm?
Have you ever wondered why you are safest in a car when out in a thunderstorm? You may have thought that it is the rubber tires that protect you, and that might be partly true. Tires are a fairly good insulator. However, the reason that you are safe in a car is due to the law of Faraday’s Cage. If lightening strikes your car, the electricity passes over the outside of it and through the wires of the vehicle. A magnetic field is created and the electrical charge that was created by the lightening strike is canceled out by the magnetic field in Faraday’s Cage. Our cars behave just like Faraday’s Cage.
What is Faraday’s Cage?
A Faraday cage can be any size; it can be smaller than a shoe box or as large as a sky scraper. The outside of a Faraday cage is made of metal, and when an electrical field is applied to it the wiring on the inside neutralizes the electrical charge. Whatever is inside a Faraday cage is safe and sound because there is no electrical charge on the inside of the cage. In essence, your car is a wired box. When lightening hits your car, the current goes through the wire and you are insulated inside your car because the current cannot touch you.
Lightening hitting car / YouTube
Who discovered Faraday’s law?
Michael Faraday (1791-1867) and Joseph Henry (1797-1878) discovered electromagnetic induction. Electromagnetic induction is accomplished by passing an electrical current through an electrical conductor which is moving through a stationary magnetic field. Though, both men worked independently on this discovery, Faraday was the first man to publish his findings in 1831.
Are all vehicles safe when struck by lightning?
All vehicles are not made the same. The Faraday’s Cage effect works when the vehicle is made of metal, which is a good conductor. The majority of the electricity is conducted on the outer skin of the vehicle, if it is made of metal. But what if the vehicle is made primarily of fiberglass, which is not a good conductor of electricity? What if you are driving in a convertible? Will you still be protected by Faraday’s Cage effect?
Truck gets hit by lightening / YouTube
It’s important that people don’t touch any metal objects that go through to the outside of the vehicle. For instance, if you are caught in a lightning storm, pull off to the side of the road and keep your hands in your lap. Don’t touch anything that could be a conductor of electricity, because you could get injured. Don’t touch your radio, your gear shift, your door handle or anything that may be connected to the wiring inside the car or truck, or connected to the outside of the vehicle.
School buses and many types of cars are quite safe in a lightning storm; however, there are makes of cars that aren’t quite as safe. Plastic or fiberglass cars such as non-metal Corvettes and Saturns are quite safe in a lightning storm because they are not good conductors of electricity, and are less likely to be struck. These plastic composite vehicles are not good Faraday cages, but unless they are very near a conductor source or on top of a high mountain, they aren’t likely to be struck by lightning.
Sources:
http://www.magnet.fsu.edu/education/tutorials/tools/faradaycage.html