Which characters in The Outsiders are round, flat, static, and dynamic?
Round characters have complicated motivations and backstories. Ponyboy is a round character, as the reader understands the multiple forces that are shaping his reactions and his personality, including the loss of his parents, the friction he experiences with Darry (his older brother), his desire to be a writer, and other forces. He is a complicated character. Darry himself is a round character, who struggles to raise his younger brothers. The reader understands that Darry is torn between being firm with his brothers and showing a more loving and forgiving side. Johnny is also a somewhat round character, as the reader knows that the harsh abuse he has received at home has shaped him into a vulnerable person. Dally (or Dallas Winston), on the other hand, is a flat character. This means he is a bit like cardboard and does not have a great deal of complexity. The reader does not really understand why he is the way he is.
Dynamic characters change, while static characters do not experience change. Ponyboy is dynamic, as he comes to understand his brother, Darry, and Darry's love for him. Ponyboy also comes to understand that his talents lie in writing and that he is not a violent person. Darry is also dynamic, as he comes to understand that he has to take a new approach to raising Ponyboy. In particular, he realizes has to be more expressive. Sodapop, on the other hand, is a static character. He is happy-go-lucky at the beginning of the book and at the end. Dally is also static, as he remains violent and does not experience much change over the course of the novel.
I would like to clear up the question a little bit. Round and dynamic are synonyms of the same type of character. Both refer to characters that change from the beginning of the story to the end of the story. Flat and static both refer to characters that typically remain the same and unaffected by the events throughout the story.
I would say that the most dynamic character in The Outsiders is Ponyboy. That makes sense, since he is the main protagonist and the narrator of the story. It would be a fairly boring story, if the narrator never changed. Pony's attitude about the Socs changes because of the events in the story. At first, Ponyboy sees the Socs as just a bunch of wound up rich kids looking for a fight. But through characters like Cherry and Randy, Ponyboy comes to see that the Socs are people just like him. They have a different set of problems, but problems none the less. Speaking of Randy, he also would be a dynamic character, because his entire attitude of the gang war changes by the end of the novel.
I think the best example of a static character is the Soc, Bob. He's just a jerk through the entire story. I would like to make the argument that Johnny is a static character too. Johnny has been changed drastically because of the beating that he received from Bob, but that happened before the events of the book take place. The reader learns about Johnny and his change in a flashback sequence, so I would say that Johnny is static throughout the events of the book.
Round characters are well developed, complex characters who demonstrate a variety of traits, some of which are contradictory. Throughout The Outsiders, Sodapop, Darry, Dally, Cherry, and Johnny would be considered round characters. They each reveal complex emotions, but they generally remain unchanged throughout the story.
Dynamic characters have experienced a permanent change throughout the story. This change is often revealed in their new attitude and outlook on life. Ponyboy and Randy Adderson would be considered dynamic characters. They both develop a different perspective on life from the beginning to the end of the novel.
Flat and static characters remain primarily unchanged throughout the story. The events in the story do not change their attitude or outlook on life. Bob Sheldon, Marcia, Two-Bit, and Steve would be considered flat/static characters.