One of the most distinct changes in mood and atmosphere in Acts III and IV of The Crucible lies in the difference between confrontation and resignation.
An intense mood dominates Act III. The establishment of the trial as the act's backdrop helps to establish this mood. Francis Nurse, Giles Corey, and John Proctor enter into the courtroom trying to protect their loved ones who have been accused of witchcraft. This establishes a very intense feeling in the Act because people's lives are at stake. It also helps to enhance a confrontational atmosphere. The reader absorbs the feeling that sides are beginning to be drawn. Francis Nurse confronts the judges over what he sees as unfair accusations. He is rebuked and is forced to relent. Giles Corey insists that men like Thomas Putnam financially benefits from taking advantage of those who are accused of witchcraft. Corey's direct challenges to the court help to increase the contentious atmosphere of the entire Act. He is taken to jail when he refuses to remain silent. When Proctor directly challenges the court with bringing Mary Warren to the stand and also discrediting Abigail, the atmosphere reaches its zenith of confrontation. Sides are clearly established and it becomes clear that only one side will emerge victorious.
In Act IV, there is a different mood. It is one of resistance. Rebecca Nurse and John Proctor are sentenced to death. Giles Corey has already been executed. The mood in the town has turned against those in the position of power. Parris has received death threats, and the court of Hathorne and Danforth no longer enjoys the public support it once did. This defiance is also seen in how Proctor ends up rejecting the forced confession and in how Rebecca Nurse goes to her death. Proctor's "goodness" is the ultimate repudiation of the trials and what they have come to embody. All of these events help to establish the resistance mood.
An atmosphere of sadness permeates the final act. From the opening where Tituba and Sarah Good are going to die, seeking divine release from their condition, to Rebecca Nurse being denied breakfast on the day of her execution, the audience experiences a very sad feeling. In Act IV, the mood of resistance resonates, but also creates a despondency within the audience. Miller suggests that resistance is difficult, but must be waged when power is abused. To see this played out with characters like Proctor and Rebecca Nurse and the fate they must face as a result creates a sad feeling within the audience.