What is the significance of the witches' scenes in act 1 of Macbeth?

Act I, Scene 1 is essentially significant in that it establishes a mood for the play as well as creating questions in the minds of the audience about the role of the supernatural in Macbeth. The witches meet to announce that they will meet again after a battle which is not named. They announce that "Fair is foul, and foul is fair," suggesting that all in Macbeth may not be as it seems. 

In Act I, Scene 3, Macbeth and Banquo meet the witches. Macbeth describes them as "wither'd and wild in their attire," and observes that they have beards. For their part, the witches greet Macbeth as Thane of Glamis and Cawdor and as "Macbeth, who shall be King hereafter!" They hail Banquo as one who "shall get kings, though thou be none," implying that his offspring will rise to the throne of Scotland. 

So in Act I, Scene 3, the witches offer the prophecies that will set Macbeth on a murderous path, and Banquo toward his death. Macbeth is visibly shaken by their predictions, and when he learns that he has been given the titles of thane of Cawdor, he realizes that perhaps the crown might be within his grasp:

If chance will have me king, why, chance
may crown me 
Without my stir. 

It turns out that neither Macbeth nor his ambitious wife are willing to wait for "chance to have him king."

What functions does act 1, scene 1 serve in Macbeth?

The opening of Macbeth establishes the magic and supernatural aspects that will play a major role in the play; by having the Weird Sisters coming together and chanting, the audience can deduce that they are setting certain events into motion. We also learn that we are entering Macbeth's world at the end of a battle; from this, we can assume that Macbeth's world is not a peaceful one and probably won't be for much of the play. The line "when the battle's lost and won" also lends to the idea that even though the battle is over, the war is just beginning.

Finally, we know that Macbeth is not significant because of his previous actions, per se, but because fate chose him to play a part. Yes, we later learn that he is a great warrior, but he becomes the main character not through his heroic deeds, but through what fate has in store for him.

What functions does act 1, scene 1 serve in Macbeth?

There is something about this opening scene that gives the play its overall tone of menacing evil. The way that the witches chant together, almost as if there words were an incantation and they were casting a spell, immediately plunges us into the world of evil and witches. We also need to be aware of the dramatic impact of such a scene on an audience. It is very easy to dismiss such aspects because we study plays like this rather than trying to visualise what they would look like. However, let us imagine we are in the audience, watching this opening scene. Depending on how the director chooses to play it, the opening scene is likely to involve darkness, thunder and a storm, dramatically introducing the witches but also casting a shadow over the rest of the play. Note too, the words of the witches and the way that they seem to represent chaos through the paradoxes of their speech. They refer to a time "when the battle is lost and one" and "Fair is foul, and foul is fair," indicating the way that they represent an anarchic state that overturns the normal order of things. Starting this play in such a fashion clearly emphasises the role of evil in the play and also highlights the importance of the witches in Macbeth's downfall.

In Macbeth, why do act 1, scenes 1 and 3 begin with the witches?

The major theme of Macbeth is the battle between good and evil and the other themes are connected to this so it seems only fitting to begin the play with the witches.

Nothing is ever as it seems in Macbeth and the witches famous words

Fair is foul, and foul is fair

already draw the audience into the concept of appearance versus reality and that there may be more than meets the eye.

Much of the action throughout Macbeth relates to Macbeth’s obsession with the witches and bringing them in at the onset leaves us (the audience) in no doubt as to the influence they are likely to have over the main character.

By the time the witches meet Macbeth, the audience is already aware that Duncan intends to make Macbeth Thane of Cawdor. It was quite acceptable and actually expected in the day that, having served his king loyally and bravely, Macbeth would be richly rewarded.

The audience is again drawn into the witches scheming when they appear shortly after Duncan's announcement and, of course, before Macbeth actually knows himself, to prophesy that Macbeth will be honored by the title of Thane of Cawdor.

Macbeth’s first words

"So foul and fair a day I have not seen,"  alludes to the initial prophecy of the Three Witches.

Even though, Macbeth and Banquo question the evil nature of the witches, Macbeth cannot help but be intrigued by the fact that, not only will he be Thane of Cawdor but King! He begins to believe it and the audience realises that maybe his rise to power will not be according to the proper order but by evil and devious means.  

The eNotes study guide will help you get a better understanding of the role of all the characters. Navigate to the summaries and character analyses.

What is the function of the witches' opening scene in act 1, scene 1 of Macbeth?

The witches set the play in motion. The first scene in Act I introduces the witches and shows that they intend on meeting with Macbeth. When the witches meet with Macbeth in Act I, scene 3, they reveal their premonitions, which inspires Macbeth and Lady Macbeth to go forth with their murderous plans in order to make the witches' prophesies come true.

What is the purpose of the opening of Act 4, Scene 1 in Macbeth before Macbeth's entrance?

The opening of act 4, scene 1 depicts the Three Witches adding poisonous ingredients into their cauldron as they cast a spell that will cause "powerful trouble." Hecate, the goddess of witchcraft, then enters the scene and praises the witches for their poisonous concoction and wicked efforts to destroy Macbeth. Macbeth then enters the scene and demands that the Three Witches tell him more about his future. The Three Witches proceed to offer Macbeth several enigmatic prophecies via apparitions, which he mistakenly views as favorable.

The purpose of depicting the witches as they create a poisonous, harmful charm provides the audience insight into their malevolent nature and applies dramatic irony as the audience is aware of their evil intentions while Macbeth is not. Macbeth is unaware that the witches are calculated in their efforts to influence his downfall and is filled with a false sense of security after listening to their second set of prophecies.

What is the purpose of the opening of Act 4, Scene 1 in Macbeth before Macbeth's entrance?

Shakespeare's Macbeth is a tragedy in which one man rises to a high position then falls, a series of events some blame either on the witches or fate.  The scene to which your question refers is a picture of how even a villainous traitor can die with dignity.

The former Thane of Cawdor has been discovered as a traitor, and he has been sentenced to die, of course.  The report of his demise has been delivered to the king, and it's clear the traitor was more honorable at the end than at the peak of his life:

...very frankly he confess'd his treasons,
Implored your highness' pardon and set forth
A deep repentance: nothing in his life
Became him like the leaving it; he died
As one that had been studied in his death
To throw away the dearest thing he owed,
As 'twere a careless trifle.

This incident, appearing so early in the play and directly prior to Macbeth's entrance, serves as a both a foil (contrast) and a foreshadowing of Macbeth's death at the end of the play.   The traitor understood his wrongs and repented, knowing he deserved his fate; in contrast, Macbeth understands he deserves his fate, but he dies fighting.

What is the significance of the opening scene of Macbeth?

First, the opening scene establishes the main character of the play: Macbeth himself. The audience becomes aware that the witches of the opening scene will meet Macbeth at a battle, and the play assumes an ominous tone. We learn that there will be dangerous conflict when a battle is both "lost and won." Though seemingly a paradoxical statement, this foreshadows that Macbeth will win in his quest to become king but will lose much, including his values, his wife, and ultimately his own life.

The opening act also establishes an element of the supernatural that will be woven into the play; Macbeth will meet with these witches who prophesy the "hurly burley" events to come. This element of the supernatural forces the audience to consider that Macbeth's world is situated on an unnatural order and that there exists a possibility of unnatural evils within the play. This sentiment is echoed in the closing of the scene:

Fair is foul, and foul is fair

A second paradox in such a short scene establishes a setting that is off-kilter. In this play, Macbeth will portray himself as a fair friend to Duncan—yet Macbeth possess a foul heart. Audience members will likely remember this paradoxical line when Macbeth echoes the sentiment in his own opening line:

So foul and fair a day I have not seen.

This line links Macbeth both to the initial ominous predictions of the witches and to the unnatural order that they have established in the opening scene.

When and why are the three witches in Macbeth to meet again?

The three Weird Sisters are planning to meet again

When the hurly-burly's done,
When the battle's lost and won. (1.1.3-4)

As the witches are speaking together in this scene, Macbeth and Banquo are busily engaged in fighting both rebel forces as well as the Norwegian king's army; this is what the sisters call the "hurly-burly." The witches intend to "meet with Macbeth," and so they must be prepared to catch up with him after the battle is over (1.1.8). When this happens, some soldiers will have lost and some will have won.

The fact that the first time the audience hears Macbeth's name spoken it is by these weird women does not bode well for him. When the witches take the stage, there is "Thunder and lightning," clearly establishing a creepy and unsettled mood. Then, the sisters end the scene with the lines

Fair is foul, and foul is fair;
Hover through the fog and filthy air. (1.1.12-13)

This, too, sounds pretty menacing. It cannot be desirable to have fair or good things seem foul, and foul or bad things seem good. Further, the idea of "fog and filthy air" is, likewise, threatening. "Filthy" never has a good connotation, and fog typically connotes creepiness and otherworldliness as well. Therefore, we have several clues that the Weird Sisters' plans for Macbeth are not meant to make his life better.

When and why are the three witches in Macbeth to meet again?

The first Weird Sister asks this very question to open the play.  The second sister replies that they will meet again after the battles in which Macbeth and Banquo are fighting have concluded, as she says, "When the hurly-burly's done" (1.1.3).  The third sister replies that this will be at sunset.  The first sister asks where they will meet, and the second says that they will meet "Upon the heath" (1.1.7).  A heath is a type of grassy, shrubby field that is often found in Scotland.  It is upon on this field, then, that the Weird Sisters plan to meet with Macbeth, and this is the next time that they will all be together.  

When they do meet again, in Act, scene 3, they spend some time discussing what they've been up to since they last saw one another: general mischief making, some malicious killing of animals, and constructing of plans to exact revenge on the husband of a woman who would not share her nuts.  Then the sisters seem to cast a little "charm," dancing around and chanting in a circle until the moment when Macbeth and Banquo arrive (1.3.38).  

In Macbeth's opening scene, when do the witches plan to meet again?

Macbeth actually opens with this very question. After asking when they should meet again in the first line of the play, the witches agree to convene at the end of a great battle:

When the hurlyburly's done; 
When the battle's lost and won.

This will be, they say, before the end of the day, and they announce that they will meet "upon the heath" where they will encounter Macbeth. The audience is not informed as to who Macbeth actually is, but it can be inferred that he is involved in the battle. The scene is obviously designed to set the plot in motion, but also to create a certain mood. The theme of opposites ("lost and won") is pursued throughout the scene, suggesting the disconnect between appearances and reality that we see throughout the play. It is clear that the witches have nothing but malevolent plans in store for Macbeth.