Hank explains the Bohr Model of an atom. He also discusses the correct and incorrect assumptions Bohr made when presenting the model to the scientific community.

Moe has to resort to his lifeline to answer the question "Which of the following is not a subatomic particle?" Unfortunately his lifeline is Homer.

Sheldon tells Penny that he is still interested in String Theory because it is elegant. He gives a brief explanation of it and states that scientists have been working on it for decades.

Gilfoyle explains to Jared that if he checks up on the Eagle eggs at the museum he might kill them because they are in a state of being alive and not alive as long as he doesn't know the outcome.

Penny asks Sheldon for advice on whether or not she should date Leonard, and during the conversation, Sheldon corrects her use of physics terms. He then explains the Schrödinger's Cat thought experiment to help her think about the situation.