In Fahrenheit 451 what is the effect on Montag when the old woman on Elm chooses to die with her books?
The old woman, who lights the match that leads to her own demise, is a catalyst for great change in Montag's life. When he met Clarisse and was so moved by her, and realized after speaking to her that he was not happy at all, he started thinking and pondering the reason why. Then he comes across this woman who would rather die with her books than live without them. This floors Montag--why would she possibly want that? He puts two and two together in his mind--he is miserable, and this lady loves her books so much that she won't live without them. He thinks that possibly, somehow, books have to have the key to happiness. He has never met anyone before who was willing to fight for something they believed in; this woman was, and it made him think that perhaps she had some answers.
It is the old woman's death that sends Montag on a journey to find out exactly what it is about books that brings meaning to life. He is so impacted that he is ill in the bathroom when he gets home, can't sleep that night and is sick the next day. In comparing his life to the old woman's, he asks himself, "How do you get so empty? Who takes it out of you?" He feels like he is spinning out of control and describes it as being the "victim of a concussion" or being "thrown from a cliff" or being "whilred in a centrifuge." He realizes, after the old woman kills herself, that something had to change. He had to find answers.
The next day, he starts to read books and seeks out Faber, who he feels can help give him answers. Montag begins his journey of self-discovery, revelation, and eventually, revolution. I hope that those thoughts helped; good luck!