In these chapters we see Julia's world begin to collapse around her. First the magnetic field snaps. Then her father ditches her.the sun gathers a new trick, being able to burn through clothes. Eventually the boy she had begun to love moves away leaving her alone with her mother, But she still continues to live and copes with everything collapsing around her.
As far as theme goes I have been able to clearly identify one. The theme I have seen is " Even in the darkest situations do not give up, because it might all get better soon." This theme is shone through the actions of Julia. She keeps on going even though she knows that the entire world comes to it's end. She continues to move forward because she has hope that she will have what she once had. She says "I do try to move forward as much as possible. I've decided to try to become a doctor" This show's that she hasn't completely given up. It shows that she will try to continue even though she's lost almost everything.
It seems that everybody's decision making has become eroded in the madness of it all. Her father, a stable family man who worked to pay bills for his family has made a complete 180 by leaving his loving wife and daughter for some lady he had be having an affair with. Julia's mother had started to make purchases behind her husbands back. Julia had even lied to her mother in order to stay at some other boys house.
It seems that as we come to the end of the story Julia takes on a more melancholy personality. By trying to cope with everything that is happening she seems to become more accepting of it all. However, she seems to hold on to everything with a little more desperation such as seth. I can figure that she is most likely slightly depressed if not very depressed, but she still manages to power on. With all that has happened she seems to have a certain determination about moving on.