In chapter 4 of "To Kill a Mockingbird," how is Jem changing? Give several specific incidents as examples.
Being four years older than Scout, Jem is approaching adolescence and expanding his horizons beyond his family and the community of Maycomb. He is an avid reader; Scout remarks: "No tutorial system devised by man could have stopped him from getting at books." He has become less gullible to fall for Dill's yarns ("In a pig's ear, you did."), and gets upset when Scout eats gum found in the Radley tree ("Spit it out right now!").
However, there are also contradictions. He is losing interest in former childhood games but refines the Boo Radly scissors scenario to a fine art. He makes Scout spit out gum from the Radley tree but then doesn't want to give up the Indian head coins found in the same place. He believes in the Negro lore about 'Hot Steams' but says he is not afraid since he knows an incantation which will ward off their curse.
Jem has learned to keep some reservation in his judgement of others, but he wants to prove himself as brave just the same. This is why he proposes enacting the "scissors scenario" at a safe distance from the Radley house.
In their childhood play it is Jem who arbitrates the "rules." He can no longer fit inside the tire to be rolled along but is willing to push, and he negotiates the turns taken between Dill and Scout. It is significant that even in games Jem wants everything to be fair.