how did opal's relationship with her father change

At the beginning of the book, Opal's relationship with her father rather formal and distant. Opal's knowledge about mother is very little because father does not speak much. Opal describes her father as being "like a turtle, hiding all the time inside his shell" (p. 67). By the end of the book, Opal's father is more opens up to his daughter: he shares his pain about his wife leaving him and is able to confide in his daughter.