based on the conversation involving Tituba, Sarah Good, and Herrick at the beginning of the act 4 of the crucible, what ocsession of the day is weighting heavily on these characters?

Miller demonstrates this immediately in the comic interlude that opens the act. Tituba and Sarah Good are foolish comic foils whose claims of communing with Satan are intended to be absurd. Yet while these women are spared the gallows because they have confessed to witchcraft, those like Rebecca Nurse who refuse to admit to a crime they did not commit remain sentenced to execution.