The opening act of a five act Shakespearean tragedy is known as the exposition. In this the key characters and themes of the play are introduced. Thus the first two scenes play a crucial role in determining the atmosphere of the play.
The first scene of any play is always a significant part, it shows how the play will be and what it is about. Scene one is very important because it sets the scene for the play. The witches chanting in the beginning gives the feeling of evil to the viewers. In addition, the backdrop and the music also affect the audience. The weather is dark, dull, and generally mauve, this works harmoniously with the hideous figures of the witches, and the barren land that they are situated in. The witches are chanting together, very strongly, and the rhyming couplets make the chant interesting to listen to. They also use paradox phrases, which make the audience think about what they are saying.
An example of this would be, "Fair is foul and foul is fair, hover through fog and filthy air." In other words, "good is bad and bad is good". Either way, bad is the "winner". The witches give the idea that they will appear again later in the play, for the first witch asks, "When shall we three meet again?" This means that they must be very important, other wise they would not be introduced in the first scene. Then she asks which horrible form of weather shall they meet in, because for the witches horrible, is always a good thing. They plan to meet Macbeth, hence, the name of the play, this shows that he is also a very important character. The second witch says "When battles lost and won". This tells us that there is a war, or a battle going on. By now the audience knows that Macbeth will have something to do with the witches, and they are left to wonder what will happen next.
Scene two is situated at a battlefield camp, firstly, the setting shows that as the second witch in scene one said, there is a battle taking place. New characters are introduced, among them king Duncan, and his son. In this scene a captain reports that Macbeth has captured Cawdor, and Cawdor is to be executed. This is the second time that Macbeth has been mentioned. The audience wonders, "Who is this Macbeth person?" It begins to unravel that Macbeth is a great man, very much liked by the people. Duncan praises him, but this is slightly ironic for later on Macbeth will be the man who kills him! Even though Macbeth has not yet appeared, the audience can see that he is currently on the high end of popularity, along side with Duncan. Later on in the play this changes, as Macbeth's popularity slowly slides down the hill to failure.
These two scenes provide a powerful exposition. Macbeth does not appear on stage although we are given an indication that he is a hero. However, he dallies with the witches. The main themes of the play are introduced, treachery, witchcraft, and the struggle between good and evil.