This novel is about youth seeing evil. How does Bob Ewell impact Jem and Scout?

In To Kill a Mockingbird, Scout and Jem learn many unpleasant facts about Bob Ewell and his family. The Ewell family does not value education, they live off of public assistance, and the law often looks the other way where they are concerned. Atticus explains that they are, "the disgrace of Maycomb." Bob Ewell, described by Scout as a "little bantam cock of a man," impacts Scout and Jem in multiple ways.
The children learn more about society and where certain community members fall in the hierarchy of Maycomb County. Scout and Jem also learn that, although the Ewells are seen as uneducated and disgraceful, they still have higher standing than the black citizens. Jem feels that the jury could not possibly find Tom guilty after the way Atticus pleads his case. However, a harsh lesson is learned by the children when Tom is found guilty. Jem and Scout realize that even though Bob Ewell beat his own daughter, the community refuses to take the side of a black man.
After the trial, Bob Ewell threatens Atticus because his credibility and pride are damaged as a result of his testimony. Jem is afraid for his father, but Atticus consoles him by saying, "We don't have anything to fear from Bob Ewell." Atticus is wrong, as the reader soon discovers. Bob Ewell attacks Scout and Jem with the intent of killing them, then they are saved by Boo Radley. This encounter with Bob Ewell teaches the children how desperate a man can be to save his reputation, while it is a man with a bad reputation who saves them.