How does Ray Bradbury develop characterization in "All Summer in a Day"?

The author brings out the characterization of Margot by showing how drastically different she is from the other children. Margot is a quiet, sensitive girl, and because she is the only child who can remember the sun, she is scorned and mocked by the other children. Bradbury states that Margot separates herself from the other children. She does not participate when the other children play games, and this physical separation is used to symbolize her differences in personality and upbringing.
Margot's character trait of sadness can be seen through many aspects of her physical appearance. She appears weak and sickly, and the author describes her as "very frail." Her eyes also give away her gloomy, almost lifeless appearance. The author says that the "rain had washed out the blue from her eyes and the red from her mouth."
He goes on to compare her voice to a ghost and to compare her to "an old photograph dusted from an album." It is clear that Margot's memory of the sun and longing for its warmth have taken a toll on her emotions. Margot's deep depression is also hinted at when it says that her parents are thinking of leaving their jobs and returning to Earth so that Margot's condition may improve.
The other children are also important characters in the story. Bradbury shows their bullying nature and cruelty when they call her a liar about the poem she writes and when they lock her in the closet. The author states that the children can hear Margot's desperate beating on the closet door and her helpless cries to be released; however, their only response is to smile and leave her there to suffer.
The author softens his harsh descriptions of the children only at the end of the story. When the sun has gone and the rain returns, they remember Margot and feel a sense of shame at their actions. Finally, they unlock the door and free Margot. The author seems to show the reader the destructive effects of jealousy through the actions of the children.