In A Raisin in the Sun by Lorraine Hansberry, why does Walter give Travis more money than Travis asks for? What theme in the play does this...

As Hansberry opens the first act, the reader understands the poverty that this family deals with daily.  From the description of the worn out furniture to the fact that the family cannot give Travis 50 cents for school, poverty seeps out of this first reading.  As well, Hansberry puts Ruth and Walter Lee in conflict with each other, and the scene with Travis is a great example.  As Travis is asking his parents for the money, Ruth keeps it simple by telling Travis the truth: They simply don't have the money.  However, when Walter Lee inserts himself into the conversation, he doesn't want his son to hear that the family is poor; he wants Travis to keep dreaming.  So, he hands Travis the money, but during the entire exchange, he is looking directly at Ruth, because this transaction is not about the money: It's about Walter Lee having the power to give his son money and it's about taking that power from Ruth in front of Travis.  However, moments later, Walter Lee has to borrow money from Ruth to catch the bus because he gave away his last change.  The audience thus understands that Walter Lee's show of power is transient and temporary, and his push to have power is a huge theme in the play.