Since we lack a means of effectively preventing lightni […]
Since we lack a means of effectively preventing lightning, we provide it with a low resistance path to ground connected to a high, pointed conductor; a lightning rod.
The pointed rod encourages ionization of the air by compressing charges into a small area; when a massive charge difference builds up during a storm, positively charged “streamers” of plasma air are emitted by the point, reaching towards connection with a “stepped leader” in the sky. Once the connection is made, a lightning strike occurs.
The idea is to get lightning to strike where we want it to, as opposed to random portions of a structure which may explode or burst into flames.
A lightning rod on a radio tower emitting a positive streamer before the strike.
3-phase power lines protected from lightning by a single, grounded “shield” conductor at the very top.