Final answer:
Atticus Finch is looking at Scout with curiosity and sternness due to something unusual he notices about her during their moment together after a fire. Scout's reaction is not detailed, but she likely responds with confusion or defensiveness.
Step-by-step explanation:
In the novel To Kill a Mockingbird by Harper Lee, at the moment Scout refers to, Atticus Finch is observing his daughter with a blend of curiosity and severity because he notices something about her that surprises him. On that winter night, after a fire has threatened their neighbor's house, Atticus and his children return inside to warm up with hot cocoa. While not explicitly stated in the passage provided, the implication is that Atticus may have seen something on or about Scout that raised his concern or warranted his attention. Scout's reaction is not detailed here, but based on her overall character, she may react with confusion or defensiveness to her father's scrutinous gaze.