What is the difference between Baptism and Confirmation in the Catholic Church?

Is there a list of specific differences between what Confirmation is and what Baptism is, and why we need both (especially Baptism) in the Catholic Church? From an observer, they seem pretty similar. Anointing, sponsors, lots of things suggesting the Holy Spirit. But there has to be some reason that both continue to exist as separate sacraments, so what are the differences between the two and what does Confirmation do that Baptism doesn't?