Naturally, both of the children grow physically during the nearly two-and-one-half years that encompasses the novel. Scout does not really discuss her own growth spurts, but we know that Jem is growing taller and approaching puberty. He is proud of the body hair that has begun to appear, and he plans to try out for the football team when seventh grade rolls around. Jem's new maturity sometimes infuriates Scout, but she is happy when he presents her with a Tootsie Roll and some advice after a particularly bad argument with Aunt Alexandra. And at the end of the novel, he does his best to defend Scout from the murderous hands of Bob Ewell, fighting him off the best he can until Boo Radley arrives.
Lost innocence is a major theme in the novel, and both of the children are robbed of some of their childhood inculpability in the adult world to which they are exposed. They quickly learn not to believe most of the gossip spouted by Miss Stephanie, and soon recognize that the monstrous Boo Radley is actually trying to become their friend. They find that their seemingly boring father has a few secret talents of his own, and Jem decides to emulate the humble nature of Atticus, announcing to Scout that "Atticus is a gentleman, just like me!" Both of the children learn the hard way about the injustices found in the adult world: that racisim exists; that religious zealots are often hypocritical (Mr. Radley, Mrs. Merriweather); that teachers are far from perfect (Miss Caroline, Miss Gates); that family heritage can be interpreted in different ways by different people; and that good people (Tom Robinson, Boo Radley, Dolphus Raymond, Mrs. Dubose) are often misunderstood and believed to be bad. They see how evil exists in the human form (Bob Ewell) and how evil can sometimes be overcome (the lynch mob). Jem decides he may want to follow in Atticus's footsteps as an attorney just so he can improve the jury system.
As for Scout, she finally understands that fisticuffs are not a solution for an argument, and she discovers puppy love in the tiny but imaginative persona of of Dill. She still questions the goodness of most women, finding herself "more at home in my father's world"--the world of men. And at the end of the novel, she discovers how different her neighborhood looks from the perspective of the Radley porch and how people are not always what they seem.