The children learned thought Atticus is a very good shot, and not as old and useless as they thought.
When the children spy Tim Johnson acting strangely, the town snaps into action. Heck Tate and Atticus are called to the scene, and they try to head the rabid dog off before it bites someone. A rabid dog is very dangerous.
The children are very surprised when they see Heck Tate had the gun to Atticus. They think of him as old and worthless because he doesn’t play football like other dads.
"Take him, Mr. Finch." Mr. Tate handed the rifle to Atticus; Jem and I nearly fainted.
"Don't waste time, Heck," said Atticus. "Go on."
"Mr. Finch, this is a one-shot job." (ch 10)
Heck Tate does not feel comfortable shooting the dog, because if he misses the dog will have reached the danger zone. He hands the gun to Atticus, and Atticus hits the dog with one shot. The children are impressed and surprised. They had no idea their dad was capable of this.
Atticus’s shooting the dog and saving the town is highly symbolic. When Maycomb is in trouble, it turns to Atticus Finch. Just as he shoots Tim Johnson, Atticus defends Tom Robinson to save the town from itself.
This event is pivotal in the children's relationship with their father. At the beginning of chapter ten, Scout bluntly describes Atticus as "feeble" and "nearly fifty." His eyesight is poor and he works in an office rather than toiling at a more physically demanding job, which the children seem to associate with masculinity. He can't even really play football with Jem, like the other fathers do with their children. Ultimately, Jem and Scout are not really proud of Atticus: "there was nothing Jem or I could say about him when our classmates said, "My father—" (89). So when a local dog named Tim Johnson begins lurching through the streets of Maycomb mad with rabies, the children are stunned when Sheriff Tate hands a rifle to Atticus. The sheriff is afraid that he will miss the dog, potentially harming one of the nearby houses. Atticus brings the animal down with a single shot to the head, saving the neighborhood from imminent danger. Jem and Scout are flabbergasted, and Miss Maudie, when she tells them that their father was once known as "One-Shot" Finch, adds to their amazement. Jem in particular is very proud, even as he tells Scout not to tell anyone about the event. If Atticus had wanted people to know he was such a fine shot, Jem reasons, he would have told them. But the young man is clearly impressed by his father, exclaiming, "Atticus is a gentleman, just like me" (99). He seems, in fact, more impressed by his father's modesty and gentleness than by his shooting skills. So the children learn not only that Atticus is more useful than they imagined, but that he is a modest man who does not seek to trumpet his achievements.