When the charge is applied, if the upper plate is negative, we would expect that the negative droplet would be repelled at a rate exceeding the gravitational fall.

当电荷起作用时，如果上边的板子是负电的，我们可以期待负电的液滴会,超过重力下降速度的速度被排斥。

麻省理工公开课 - 固态化学导论课程节选