The Physics of Being Dick 3rd Rock from the Sun : Season 3 Episode 21

Dick demands that Sally and Harry get jobs, so Harry gets work in a bar (Happy Doug's) and Sally as Mary's research assistant. However, upon finding out that Sally has chosen Mary's subject (anthropology), he worries that physics is too boring and strives to spice it up for Tommy's career day. After this goes badly wrong he decides that he wants to be a cop, like Don.