Knitting or Crocheting Scarfs? Which is Easier?

My 12 year old niece is spending the summer with me, and for whatever reason, she really wants to learn how to make a scarf and a throw blanket. I know absolutely nothing about crocheting and knitting, so I have a couple questions. First of all, are scarfs generally knitted or crocheted? Same with blankets. Also, which do you think would be easier for her to learn? ( I was planning on buying her a book to help her learn, since I have no experience whatsoever.) Thanks!