it’s been one long thunderstorm here for the past day or so and last night i was driving home watching the lightning and feeling nice and safe in my faraday cage of a car when i realised that a convertible with the cloth roof up is not a faraday cage and would not be a faraday cage even if i put a fibreglass hardtop on it. ooops. i might stay at the office until the storm has passed next time…

the idea behind a faraday cage is that electrical charge doesn’t visit the inside of a metal object, it just distributes itself over the surface. a metal car is a long way from a perfect faraday cage (it’s got windows for a start) but it’s enough of an approximation to make you safe from lightning strikes inside it. i’ve found some suggesstion that the science of faraday cages is irrelevant to lightning because it deals with static electricity and that cars are actually safe because of a “skin effect” but this seems to be practically (if not fundamentally) the same thing to me.