Regarding lightning rods
It is not exactly true that lighting rods don't "attract" lightning, for two different reasons.
1. A sharp point tends to improve the ability of static electricity to make the leap into the air. This is most likely due to the lower resistance of the metal and the tendency of all the available charge to be focused at the single highest point (closest to the opposite charge) rather than diffusely spread across a broad surface. Lightning strikes are essentially gigantic capacitor discharges. If the stored capacitance is spread out over a large area, it just doesn't jump the air gap as well.
Example: if you take a static electricity generator and set two steel balls exactly 1" apart (hooked up to leyden jars or some other capacitor), you will get loud, powerful sparks. If the same setup is hooked up to steel pin points exactly 1" apart, the frequency of the sparks is greater, but the spark is weaker, because less electricity was stored before the spark jumped the air gap.
2. By providing a point of least resistance to the ground, you are also providing a path of least resistance to voltage accumulation. Most ground to sky lightning is the result of raindrops carrying electrons to the ground, where they pool. Conversely, the clouds become positively charged by the same mechanism. Eventually, the voltage peaks in a location most favorable for the transfer of electrons, and we have lightning.
If the lightning rod is well grounded, it will definitely improve the transfer of static voltage to the top of the building, where it will certainly be more likely to be involved with a lightning strike.
Perhaps some electrical engineer will pipe in with better info on this topic.
It is not exactly true that lighting rods don't "attract" lightning, for two different reasons.
1. A sharp point tends to improve the ability of static electricity to make the leap into the air. This is most likely due to the lower resistance of the metal and the tendency of all the available charge to be focused at the single highest point (closest to the opposite charge) rather than diffusely spread across a broad surface. Lightning strikes are essentially gigantic capacitor discharges. If the stored capacitance is spread out over a large area, it just doesn't jump the air gap as well.
Example: if you take a static electricity generator and set two steel balls exactly 1" apart (hooked up to leyden jars or some other capacitor), you will get loud, powerful sparks. If the same setup is hooked up to steel pin points exactly 1" apart, the frequency of the sparks is greater, but the spark is weaker, because less electricity was stored before the spark jumped the air gap.
2. By providing a point of least resistance to the ground, you are also providing a path of least resistance to voltage accumulation. Most ground to sky lightning is the result of raindrops carrying electrons to the ground, where they pool. Conversely, the clouds become positively charged by the same mechanism. Eventually, the voltage peaks in a location most favorable for the transfer of electrons, and we have lightning.
If the lightning rod is well grounded, it will definitely improve the transfer of static voltage to the top of the building, where it will certainly be more likely to be involved with a lightning strike.
Perhaps some electrical engineer will pipe in with better info on this topic.