[j_seigh]

Lighting rods also work by dissipating the local electric potential and reducing the likelihood of a lightning strike. That's why they are pointed, or fractal in the newer ones.

From https://en.wikipedia.org/wiki/Lightning_rod "and that a considerable electric current can be measured through the conductors as ionization occurs at the point when an electric field is present, such as happens when thunderclouds are overhead."

You can get a ground charge even when thunderclouds aren't present. It just has to be windy. I've always wondered if it was worth collecting this, say with a field with a grid of interconnected lightning rods in a windy location.

[quinncom]

It must have been so fun to be Benjamin Franklin. He installed an electric bell in-line on his first lightning rods so that this increase in electrical potential would cause the bell to ring, signaling that the danger for lightning was increased.

You can experience this voltage potential firsthand: take a friend to a hill or somewhere where high‑voltage power lines are nearer to the ground. One person, wearing rubber-soled shoes, stands tall with an arm in the air. The other squats down with both hands on the ground. The standing person uses the non-raised hand to gently touch the sensitive skin of the other person (ear lobe, lips), and they can feel an electric arc.