What Atticus does in this chapter that is brave is he shoots a mad dog, Tim Johnson. This may not sound all that brave, but it is brave for two reasons:
- First, Atticus hasn't held a gun in years. He used to be a great shot, but who knows if he still is?
- Second, and related to that, he has to hit the dog. Otherwise, it might get away and hurt people. And if he misses, the bullet might hit someone since he has to shoot right there in town.
The kids are shocked because Atticus has never shown any desire to do anything "manly" like shooting and they have wished that he would.
Atticus isn't brave in the traditional, more common, ways of the world. For example, Scout starts off chapter ten discussing all of the things that other fathers could do but Atticus doesn't. She compares her father to others in the community by saying that he doesn't play football, farm, arrest criminals, work on cars, or do any other manly things. She also points out the fact that he wears glasses and is practically blind in his left eye. None of those are heroic qualities like those that other fathers seem to have. Scout even implies that Atticus is a coward because he asked her to stop fighting for him. She says that she committed herself to "a policy of cowardice" because she wouldn't fight anymore. Not only that, but her father wouldn't even teach his own kids to shoot the air rifles that they received for Christmas, which seemed to solidify the fact that Atticus was not brave. Maudie tries to defend Atticus to Jem by saying that he's the best checker player around, but that doesn't count as brave to the kids. As a result, the kids feel ashamed of their father.
Because of all the reasons listed above, Jem and Scout are shocked when their father takes out the mad dog in one shot with the sheriff's gun. This is a brave thing for him to do because the town has never experienced a mad dog in February. Plus, Scout says that Tim Johnson isn't acting like a normal mad dog:
"I thought mad dogs foamed at the mouth, galloped, leaped and lunged at throats, and I thought they did it in August. Had Tim Johnson behaved thus, I would have been less frightened" (94).
What Scout says above is exactly what she's been taught by the community. This is what they all know and understand of how mad dogs behave. The fact that the dog is doing none of these things, and in February, makes this situation even more dangerous. No one really knows what to expect from this dog and they need to take care of it immediately.
Atticus is brave because he finally decides to take the sheriff's advice and shoot a gun after three decades of never using one. Also, he places himself in harm's way in an effort to save others. This is heroic and something Scout and Jem never expected from their father. Jem and Scout are very proud of him after this event.