Why does hair float when people touch an electrostatic ball?

Because the electrostatic generator can generate high voltage through mechanical transmission (van der Graff generator) or electrostatic high voltage generator, before the test, the experimenter stands on the insulating table, puts his hand on the high voltage ball, and then applies pressure. At this time, if the high-voltage ball is discharged several times with a discharge rod, obvious sparks can be seen. Because the human body is standing on an insulating platform, the human body and the high-pressure ball are equal. Therefore, it is very safe for human body, but because the electric field of the high-voltage ball to the ground is very large, the distance from the ground is equivalent to a point charge, and the hair is charged with static electricity, so that the audience can further understand [b] the principle of "like charges repel and opposite charges attract" [b].

Simply put, after being electrocuted, the whole person will have the same charge, including the hair. Because the same sex repels each other, the hair repels each other, and the farthest distance between the hairs stands on end.

On the fourth floor, it was electrified by high voltage, so it might not fall down. The key depends on the surrounding thermal insulation performance. If there is only potential and no current, it will do no harm to human body. And if there is current in the human body, the whole person becomes a conductor. This phenomenon is called breakdown. There is no charge in the body, so it won't stand up.

The charge of the scalp and each hair is the same, and everyone repels each other, so the hair is far from the scalp, and the hair is separated from the hair. However, because the static force is not enough to pull the hair off the scalp, it will stand up.