A metal
rod with a
pointed tip which is placed on top of various
structures to
protect them from
lightning.
The lightning rod does not
repel lightning, as is commonly
believed. Rather, the pointed end of the rod produces a very strong
electric field that causes lightning
discharges to occur very frequently. These many small discharges can be safely carried to
ground through a
wire; a single
massive strike,
on the other hand, can cause a lot of
damage.