Jem begins the novel as a true child and becomes a young man by the end. Over the course of the action of the book, Jem learns some important lessons, faces moral and physical challenges, and loses some of his innocence as a result.
The older brother to Scout, Jem enjoys playing with his little sister when the novel opens.
Jem is a quick-witted but fun-loving ten year old who spends a lot of time in creative play with Scout and Dill Harris...
As a child, he is imaginative and brave, but unaware of any sense of dignity in himself or others. Episodes involving childish superstition, ignorant abuse of a reclusive neighbor and petulant fights with his sister help to characterize Jem as a child in the first half of the novel.
However, as the novel goes on Jem drifts away from childhood and from his sister, demonstrating a new-found patience and maturity. Jem directly states his intentions to be a gentleman like his father and is challenged to live up to that example by the events surrounding Tom Robinson's trial.
He has been raised by his father to be strong in his beliefs and to stand up for what is right. During the trial he sees unfairness, bigotry and hatred. He realizes that right does not always triumph.
Jem grows troubled and isolated as a result of the trial, but learns to accept the things he has seen as a part of the world he lives in. As he navigates the real life difficulties he encounters, Jem becomes Scout's protector instead of her playmate, taking the first steps toward becoming the mature and courageous gentleman that he believes his father to be.
jem acts like a kid in part 1. in part 2 you see jem matureing and acting more wise about stuff. he finds scout more annoying and wants to be alone more