They were asked to perform ten different movements, including moving the wrist in a circular motion and moving their elbows.

VOA: special.2009.03.10

You've got negative charge in motion, and it's in a circular orbit.

负电荷在运动，它们处在一个环形的轨道中。

麻省理工公开课 - 固态化学导论课程节选