A dynamic character is one who changes, typically because of some conflict he or she encounters.

Kenny transforms in his views of Byron. For much of the book, Kenny sees his brother as a tough, wisecracking older brother who is there when he's in a bind, but their relationship is fairly superficial. He doesn't really trust him, particularly if Byron happens to be treating him with rare kindness. In chapter 6, he mentions that "Byron was being too nice, so I knew something bad was about to happen." And later he comments, "I wasn't used to being this friendly with Byron so I guess I was kind of nervous."

However, when Kenny needs an emotional rescue after the church bombing, it is Byron who alleviates his fears. Byron both comforts him by keeping him company and being honest with him about what he saw at the church, and he tells Kenny that there is no magic in the couch that will heal him. Kenny will have to figure out how to live in a world with people who commit horrendous acts. This is part of Kenny's transformation.

In many ways, this is a coming of age novel. Kenny has a new understanding of his world, one that Joey is still shielded from. Kenny understands that the world can be cruel and that sometimes violence finds even the most innocent of people in the most holy places. He also learns that life is precious. After nearly losing Joey, Kenny has a renewed appreciation for his family and a new perspective about the importance of their time together.

A dynamic character grows and changes over the course of a story. Kenny undergoes a number of changes as he experiences the events depicted in the novel. For instance, Kenny initially sees Rufus as his ticket out of being bullied but later adapts to the situation and is eventually excited for them to be close friends. A more significant example is that after the church bombing, Kenny regrets running away in fear rather than rushing in to save Joey. Kenny's brother, Byron, who Kenny looks up to, saved Kenny when he was in danger, and so Kenny feels that he should have acted to save Joey. Eventually Byron calms him down and convinces him that he doesn't need to feel guilty, but the lesson will undoubtedly stick with Kenny.

In literature, a dynamic character is a character who changes throughout the course of the story. The opposite of this is a static character.

Kenny Watson, a character in the novel The Watsons Go to Birmingham, written by Christopher Paul Curtis, is a dynamic character. Kenny changes from a young boy who gets bullied in the fourth grade to an older boy who believes in himself and his own abilities. Kenny, as a grade school student, would rely on his older brother to protect him from other people and things in the world. At one point, Kenny spends time hiding behind a couch because he is so afraid of the world and the horrible things that happen. Kenny changes into a boy who believes in himself when his older brother tells him how brave he is for finding his sister after the bombing in the church. This story is a story of growing up as well as the importance of sibling bonds.

Kenny is a dynamic character because he changes from a scared kid who believes in magical powers to someone who understands his inner strength. At the beginning of the book, he is constantly scared and harassed by the bullies at his school, and he relies on his older brother, Byron, for protection. Later, he almost drowns while swimming in Alabama, and he believes, as Byron tells him, that a mythical creature named a "Wool Pooh" (a misunderstanding of his grandmother's pronunciation of "whirlpool") is to blame. He says, "I found out that the Wool Pooh was real and big and mean and horrible and that he didn’t care at all about dragging kids out into the water!" 

Kenny is a dynamic character because he changes from a boy that admires his brother to a young man who finds his own way.

A static character is one who does not change or grow over the course of the book.  A dynamic character develops, changes, learns and grows.  An example of Kenny being a dynamic character is his reaction to his brother Byron.  At first, Kenny worships Byron.  His older brother is interesting because he is defiant and has Grand Adventures.  After a while, Kenny realizes that Byron is not the kind of person he wants to be.  He decides to make his own choices and be his own person.