What are chapters 2-4 about in "To Kill a Mockingbird"?
These chapters introduce one of the main themes in this story: understanding other people's perspective, or as Atticus puts it:
You never really understand a person until you consider things from his point of view . . . until you climb inside of his skin and walk around in it.”
Scout, the protagonist, comes face to face with this in her dealing with Walter Cunningham. She gets angry at Walter for causing the situation that lead to her being punished, but she fails to understand how difficult Walter's life is. This leads to her conflict with Calpurnia, who criticizes Scout for making fun of Walter's eating habits. Scout can't understand what it is to be as poor as Walter, and Atticus gives her this advice to try to help her understand.
Miss Caroline must also learn this lesson. She tries to teach all the children as if they are exactly the same, but she constantly runs up against comments like, "He's a Cunningham," or "He's a Ewell." Her frustration and anger on the first day of school stem from her inability to recognize the individuals and their particular backgrounds.
The introduction of Boo Radley in Chapter 4 will further this theme along, and it this character in particular that will recur in Scout's life to highlight the meaning of Atticus' words and to show for the reader, in the last chapter, Scout's coming of age.
In Chapter Two, Scout goes to school for the first time and immediately gets into trouble with her teacher, Miss Caroline, for being too good at reading and for explaining the impoverished circumstances of Walter Cunningham.
In Chapter Three, Scout punishes Walter for this and then invites him home for lunch upon the prompting of Jem. This introduces Scout to one of Walter's strangest behaviors--his habit of pouring syrup all over his meal. When they return to school, Burris Ewell creates chaos and then leaves the class, having satisfied his mandatory first-day-of-school policy. The chapter ends with Atticus convincing Scout that she must continue to stay in school.
In Chapter Four, the school year progresses without much interest, as Scout is too advanced for her class. At the beginning of summer, she--along with Dill and Jem--play all sorts of games, including rolling around in an old tire and acting out the Radley family history.