In chapters twenty-eight and twenty-nine, what details add to the mounting tension before Jem and Scout are attacked?
One of the largest details that contributes to the spooky feeling leading up to the attack on Jem and Scout is the fact that it is taking place on Halloween. The weather is described as "unusually warm for the last day of October" with the wind blowing strongly, the moon absent from the sky, and the street lamp casting sharp shadows onto the Radley house. Plenty of foreshadowing occurs within the discussion between Jem and Scout themselves, with Jem stating:
You know Atticus wouldn't let you go to the schoolhouse by yourself... The yard's a mighty long place for little girls to cross at night... Ain't you scared of haints?
The night is, in fact, so dark that the children trip over random obstacles without light and only manage to navigate based upon "feeling [their] way forward." They experience an early spook when Cecil Jacobs leaps at them in the dark.
This eerie experience of walking to the school is only magnified on the way back home. The children move across the black schoolyard with Jem sensing something following them. The stillness of the night makes the rustling noises behind them particularly strange; when the children finally realize that it is the swish of trousers moving and running footsteps, they take off into the night in absolute terror.
In Harper Lee's To Kill a Mockingbird, the author creates the mood for chapters twenty-eight and twenty-nine by providing these details:
The wind was growing stronger, and Jem said it might be raining before we got home. There was no moon.
Walking past the Radley place, the kids talk about Boo, and how it's a scary place. They speak of ghosts (haints). As they pass through the school yard, it is pitch black. Cecil Jacobs jumps out at them, scaring Jem and Scout.
After the pageant, the children begin the walk home. It is black outside. Scout struggles to keep her balance, still dressed as a ham. The wind has died down, but the stillness in the air promises a thunderstorm.
Jem is hesitant, listening, though at first he says nothing. Then he draws Scout's attention to the sound he hears: there are footsteps following them: what is worse is that the steps stop when they stop. Besides the sound of the wind, they kids can hear the rubbing of cotton on cotton as someone's pants rub together in time to the footsteps.
All of a sudden...
He was running, running toward us with no child's steps...
and Jem screams for Scout to run.