Comment Re:That... (Score 2) 242
The 9V battery probably saw precisely none of that voltage. Chances are, the way it was set up is to put 75kV on one post and -75kV on the other, giving a potential difference between the posts of 150kV. The electricity then arced from one post, through the metal in the CD, to the other post because the metal provided a path of less resistance than the air over the CD. Once the metal was gone from the CD, it arced though the chassis of the motor mostly (from what I could see). There was no reason for the arc to pass through the battery terminals since the chassis provided a much shorter path.
Now, had they placed the battery in line with the arc, that probably would not have ended quite so well...
Now, had they placed the battery in line with the arc, that probably would not have ended quite so well...