I love the Sassafras books. They work great as a science unit but this is just PART of teaching them. This is a story, it has facts on the different topics but the point of the book is to get kids interested in this topic and have fun with it. When you are done reading each section you fill out a log book page (or lapbook) to go with the thing you learned, plants for this book, and it is your job to research it more. The teacher guide gives you a lot of ideas on other books to read with it (short passages so its not like reading another chapter book) or websites and projects to go with the unit. Some parts are obviously very silly and its easy to say "Ok so lets see if that can REALLY happen.." and make it fun to research it more. This should not be where you are getting 100% of your information. The facts the kids in the books are accurate, but it is done in a non-fiction book.