In chapter 9 Uncle Jack learns a little about how to talk to kids. The first thing he learned from Scout. When he pulled her away from her fight with Francis, he didn't listen to her side of the story. Scout says,
"Well, in the first place you never stopped to gimme a chance to tell you my side of it--you just lit right into me. When Jem an' I fuss Atticus doesn't ever just listen to Jem's side of it, he hears mine too."
So he learns that he can't jump to conclusions with kids. He needs to hear both sides of the story before acting.
Secondly, he learns how to answer the more difficult questions that kids bring up. Scout wants to know what a "whore lady" is, since she's heard that and used it, but didn't know what she was saying. Instead of telling her the truth, Jack goes only avoids the question and confuses her more. Atticus told him to get to the point and tell kids the truth.
"When a child asks you something, answer him, for goodness' sake. But don't make a production of it. children are children, but they can spot an evasion quicker than adults, and evasion simply muddles 'em."
This is what he learned from Atticus in the same scene.