I started out having them write down ideas on their slates for why authors write. I got responses like, "to earn money," "to get their feelings out," "to entertain people," "to write about things that are funny," "to teach people," and "to give information." Then they mix-pair-shared with partners and we shared whole group.
Then really quickly, we went over the PIE. P=persuade, I=inform, and E=entertain. For guided reading, I had asked the kids to make a list of facts about themselves. Before getting these out, we talked about what facts are, and how they give information. I showed them three books, and asked a couple of students to pick out the one they thought gave information (of course, the first kid I picked picked wrong, but oh well! The next two figured out it was the National Geographic book). Then I grabbed their papers, and read off some of their facts about themselves, and let the students guess who it was in the classroom. We talked about facts that gave us information like dates and places, and other facts that told us what students liked or didn't like. They thought it was really fun to guess who the facts belonged to :)
Tomorrow, their guided reading assignment will be to give me 5 different, PERSUASIVE reasons why they should be allowed to go to Field Day :) We'll see how that goes!