This happens during a Christmas visit to her aunt Alexandra's house. Francis insults Atticus and his defense of Tom Robinson, leading to an argument where Scout defends her father and stands up for what she believes is right.
While it's not a physical fight, this exchange is a crucial moment in Scout's development. It showcases her growing understanding of justice, her loyalty to her father, and her willingness to stand up for what she believes in, even when facing opposition from family members.