When Bernadette joins the guys and Penny for their usual Chinese take-out dinner, Bernadette, the microbiologist, becomes fascinated with Leonard's physics project. Both Howard and Penny become a little jealous of this new friendship. Howard sees what Leonard is doing as the way he himself tries to pick up women, and as such wants Leonard to uninvite Bernadette to view his upcoming experiment. Penny, on the other hand, wants to bond more with Leonard by learning "a little physics" from Sheldon, who agrees if only because he can treat it as a scientific experiment. When Sheldon wants to go through 2,600 years of physics history, Penny may regret her choice of teacher.