What do Scout and Jem learn about the black community from their experience at Calpurnia's church?

Inside the church, everything is much simpler than in the church she is used to, and there are no hymnbooks. Reverend Sykes announces that the collection taken up today will go to Helen, the wife of Tom Robinson. Calpurnia's son Zeebo, the town's trash collector, leads the congregation in hymns, singing each line and having the group repeat it back to him. Reverend Sykes gives a sermon, which seems similar to the sermons Scout is used to, except that he makes examples of particular people in the congregation to illustrate his points. After collection time, the Reverend counts the money collected and announces that they must raise ten dollars to give to Helen Robinson. He orders for the doors to be closed until everyone gives more.

After the service, Scout asks Reverend Sykes why Helen needs the collection money when she can still go to work and take her children with her. Reverend Sykes explains that she may have trouble getting any work in the fields now. Scout asks Calpurnia about this, and Calpurnia explains that it's because Tom has been accused of raping Bob Ewell's daughter. Mr. Ewell had Tom arrested and put in jail. Scout remembers that the Ewells are the ones who only come to school once a year, and are what Atticus calls "absolute trash." Calpurnia won't tell her what rape is. Scout then asks her why they don't have hymnbooks at her church, and Calpurnia explains that only a few people at the church can read. Scout also learns that Calpurnia used to work at the Landing for Miss Maudie's aunt, Miss Buford, who taught her to read. Jem asks Calpurnia why she doesn't speak with proper grammar around black people, and Calpurnia explains that it would be out of place, and that she would look pretentious. The others don't want to learn to speak the "right" way, she says, so she speaks their language.