Please settle an argument. The reason that lightning doesn't zap people inside a car is the rubber of the car's tires. True, or not?

-- Joe G., Phoenix

Not, Joe.

It's because the metal body of the car forms what's known as a Faraday cage. That's an enclosure that excludes electromagnetic fields. Electric charges on the surface of the cage repel each other and don't enter the enclosed space.

The cage was built and the principle explained by Michael Faraday in 1836. He's the guy for whom an electric unit is named (the "Farad").

Such cages are widely used to protect electrical equipment. Airplanes are Faraday cages.

Incidentally, most cars are Faraday cages. Fibergalss cars are not, nor are convertibles.

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