What idea separated the two sides in "All Summer in a Day"?

The theme deals with isolation, bullying and jealousy

Explanation:

The story is about a group of children who bully a girl, from Earth. A girl named Magot who has moved to venus from the earth tells them about the sun. The children in the venus who have never seen the sun bully her saying she was lying. The children on venus are jealous of her experience on earth and were bulying her. Just when the sun was about to appaer, they said her predications were wrong and shut her in a room. Magot isolates from the children and feels that the children on earth are better.