In Chapter 17 of To Kill a Mockingbird, what does the reader learn about the sort of person/father Bob Ewell is?
Consider the impressions he makes on the judge, lawyers and spectators and how this may affect te reader's belief in his testimony.
In part of the courtroom scene, Chapter 17, in To Kill a Mockingbird, Bob Ewell is out of his element, so he does feel anxious under the gaze of those in the court, certainly in light of the fact that his (and his family's) history in Maycomb is one of squalor and lack of education. However, Mr. Ewell does at times grow confident when he thinks he has the better of Atticus. "He seemed to grow ruddy again; his chest swelled, and once more he was a red little rooster" (186).
But overall, Ewell is defensive and awkwardly accusatory of Tom. When he describes what happened to Mr. Gilmer, he hesitates. ". . . but when I got distangled I run up to th' window and I seen--" Mr. Ewell's face grew scarlet. "--I seen that black nigger yonder ruttin' on my Mayella!" (182). He hesitates and his face gets red; classic signs of fabrication. His defensiveness and lack of sense reveal that he has no social skills. This comes from a lack of association with other people (he has been isolated from the community for his entire life); this is something that has occurred in his family for generations.
Atticus reveals Mr. Ewell's lack of social skills and he reveals his ignorance with subtle but obvious questions during his testimony. Mr. Ewell's awkward and defensive behavior implicate the possibility of his lying but they also show his inability to communicate politely and his inability to behave socially. Family life is also a social life. Therefore, if Mr. Ewell can't behave like a civilized man in town or in court, the implication is that he also behaves inappropriately in the social world of his own family. At the end of the chapter, and into Chapter 18, Atticus shows that Mr. Ewell is the more likely culprit, thus exposing that Mr. Ewell's anti-social behavior might often erupt into violence (confirming many long held suspicions of many in town).