Hello, I'm a little confused about the statements regarding conductors grounded to large conductors, as the Earth. Basically, my physics textbook says that metal sphere with a positive charge and ground it to the Earth, electrons from the ground will neutralize the positive charge. That's understood. But is this to say that the Earth, or any large conductors can only neutralize positive charge? If a building is struck by lightening and there's a lightning rod on the top of the building, doesn't the lightning rod conduct the enormous charge to the Earth, which is the opposite of my first example? So I can't seem make this concept disambiguous, as I thought that an entity could only have one of the two features. I am having the same conceptual problem with the Van de Graaf generator. There's a girl touching the dome, subject to electric potential, while standing on a platform insulating her from the floor. So she's not grounded. If she was grounded to the Earth, would it be the Van de Graaf generator conducting the charge to the Earth, or the Earth neutralizing the girl?
I know this is very basic, yet it's not altogether clear to me. So an answer is deeply appreciated.