A scene can be used in different ways within a play to develop the plot. In many plays, like those of Shakespeare, the relocation of characters and/or the break in the play's action takes place with the changing of a scene, which is defined as:
a division of an act presenting continuous action in one place; a real or imaginary prospect suggesting a stage setting
The plot is basically the story being told in the play. Candace Schaefer defines plot as:
"The series of events in the story, chronological or not, which serve to move the story from its beginning through its climax or turning point and to a resolution of its conflicts."
Plot is also why the story happens and why the protagonist learns or grows, or begins or chooses something.
In Shakespeare's plays, his acts are divided into scenes. As commas separate a list of items or ideas, etc., in a sentence, the scene breaks up the movement of the plot in the same way. In Macbeth, for example, the play has several acts. In the first scene of this play, Shakespeare presents three witches who have joined together to waylay Macbeth as he travels from the battlefield; they are bent on mischief. The audience's perception of the witches' evil and the dark and stormy weather provide the play's setting. The first scene in this play is not just a starting point, but it serves to convey the mood: the audience will expect a tragedy with the setting that is displayed. The second scene introduces the details of the battle the King of Scotland is waging, and the report of Macbeth and Banquo's heroic actions. The third scene shows the two men meeting the witches.
Each scene moves from one location to another, and employs different characters to further the plot.
In Susan Glaspell's play, Trifles, there is only one scene. It is the story of a woman accused of murdering her husband as he slept, but everything the audience needs in order to understand the wife's plight—her life in that house—is carried on primarily by the discussion and actions of two neighboring women who come to gather clothing, sewing, etc. to take to the woman in prison. Meanwhile the sheriff and some men look for evidence against the wife. The women clearly establish that the husband was brute, and that his violent and cruel actions drove the woman to a moment of insanity, when she "snapped" and killed him. While longer plays use many scene changes to move the plot along, Glaspell's use of one scene is very effective in presenting clues to the women and their emotional responses without leaving the first floor of the small house; in turn, the single scene provides a sense of suspense and an emotional response from the audience for the plight of a woman in a male-dominated world.
The scene provides important information to the audience and may change, or remain the same (in a shorter play); the plot is developed through the speech and behavior of the characters, through the use of the scene or scenes.
Schaefer, Candace, and Rick Diamond. The Creative Writing Guide. New York: Addison-Wesley Educational Publishers, 1998.