Observations of Experiments/Questions

During class today we did some experiments with a Van De Graff. One of the experiments was to blow bubbles at the Van De Graff, the bubbles reacted by repelling from the device. We also created a human chain and made a circle including the device and people got shocked, this happened because the static electricity traveled from the device and to ourselves. One of the other experiments we did was put cheerio's on the device and saw what happened, my hypothesis was that the cheerio's were going to pop off the device and I was right, I was not really sure why but I think it was because sense they were light weighted the electricity transfered into them caused the cheerios to pop off the device. we did the same thing except with napkins and first we put one napkin on top of the device and then we put a stack and the stack did not move and I think the reason behind that is because the electricity either did not transfer its self through the napkins as fast or the napkins were to heavy.

Some questions that I have about the experiment are:

1. What caused the stack of napkins to stay on the device and not fly off?

2. Why did the bubbles repel from the device?

3. What causes a shock?