I found this video about Van De Graaff generator: https://www.youtube.com/watch?v=QarKXkXox6M. At 8:14 of the video, we can see that if we put the cupcake paper upside down, the paper flies away. Otherwise, the paper gets attracted to the dome of the generator.
I'm a newbie in physics and I'm even not good at English so I don't quite understand the explain in the video. What I'm guessing is: when put upside down, electrons will gather at the edge of the paper. So, the edges of the paper will contain a lot of charges and they have the same sign as the charge of the dome (positive charge), so they repel each other and the paper flies away. But I'm not sure.
Can someone explain for me why the cupcake paper flies away when put it upside down; and gets attracted to the dome when put it straight up?