Why do you learn from Bob Ewell's testimony?
Bob Ewell is the father of Mayella Ewell, the girl Tom Robinson is accused of raping. He feels that Atticus is taking advantage of him. Mr. Ewell's story remained the same throughout his testimony and cross-examination. The reader learns a few things due to Atticus' clever cross-examination. The reader learns that Mr. Ewell isn't very educated and seems very arrogant while on the stand. The key thing the reader learns is that Mr. Bob Ewell is left-handed. This small bit of testimony shows that the injuries described by Sheriff Heck Tate was caused by someone left handed.