Explanation of the Graph:
This is a potential energy v. time graph that demonstrates Nora's conversion from an obedient housewife to an independent human being over the course of the play. In Chemistry, potential energy is based on attractive and repulsive forces between reactants: this is analogous to the tension that results from attractive and repulsive forces between characters and/or events.
Summary of steps:
Norainitial = Nora in a state of obedience (the reactant)
Noraintermediate = Nora in a state of temporary relief (reaction intermediate)
Norafinall = Nora in a state of self-actualization (product)
Norainitia + First series of events results in Noraintermediate
Noraintermediate + Second series of events leads to Norafinal