Bluntly, Calpurnia is the Finches' housekeeper. However, she is so much more to the family. She acts as a mother figure to Jem and Scout, as she practically raised them after their mother's death. Along with Miss Maudie, Calpurnia is a strong, positive female influence in Jem & Scout's lives. She is a parallel to Atticus in her lessons of politeness and compassion. She contrasts with Aunt Alexandra's harsh discipline and strict gender roles. Indeed, when Aunt Alexandra comes to stay, she argues with Atticus over Calpurnia's role. She wants Calpurnia gone, but Atticus knows how important she is to the family.
On Scout's first day of school, Scout brings home Walter Cunningham for lunch. She then makes fun of him for pouring maple syrup on hif food. Walter becomes extremely embarrassed, and Calpurnia scolds Scout. She makes it clear that guests are to be treated with respect. This is similar to the lessons Scout and Jem will learn about treating all people with respect. Calpurnia also has a loving side as well. That same day, after school, she makes Scout's favorite food, crackling bread.
Calpurnia serves as a bridge between the black and white worlds of Maycomb. She is essentially the first black woman the children have ever interacted with, & that experience shapes their ideas of race and equality. sometimes, scout finds it difficult to reconcile the Calpurnia in the house with the public Calpurnia. When the children visit Calpurnia's church with her, they face discrimination and rejection of their own. Also, Scout questions Calpurnia's language use, & realizes that this woman has many sides. Although the majority of parishioners welcome them during their church visit, one woman challenges the white children. Calpurnia responds by calling them her guests and saying "it's the same God, ain't it?"
This combination of discipline, logic, and kindness makes Calpurnia the ideal female role model for Scout and Jem.