What Does a Lightning Rod Do?

Okay, I lied.  I said previously that I was done discussing thunder and lightning on this blog, but another misconception recently popped up and I can't NOT talk about it.  :-)  The misconception focuses on lightning rods.  We've all seen lightning rods, but most of us have a couple of misconceptions regarding lightning rods.  If you ask someone what the purpose of a lightning rod is, you will most likely hear them say that the purpose is to attract lightning.  But is that really what they do?  Yes and no.

A lightning rod doesn't really attract lightning.  It creates a path of least resistance from the top of a building down to the bottom.  A lighting rod is nothing more than a long stick of metal that creates a conductive path for charge to travel.  Lightning striking a lighting rod travels safely down the building to the ground, decreasing risk of fire and computer damage to the building.  The main purpose of a lightning rod, however, is NOT to attract the lightning.  The main purpose is to slowly leak charge down to the ground to avoid a lightning strike.  In some cases too much charge still builds up and there is a strike.  In the case of a strike, the charge is safely transferred to the ground.  

Avoiding the strike to begin with is the best option, thus the main purpose of that lightning rod is to leak charge, not attract the lightning.