One of the most thoughtful current writers of science for kids is Melissa Stewart. She has done a lot of analysis of changes taking place in nonfiction and how those changes affect readers and teachers. She has an excellent piece in the School Library Journal on types of nonfiction, and on connecting kids with the books that best suit them. As she observes:

Research clearly shows that many students (up to 75 percent, in some studies*) enjoy expository writing as much as or more than narratives. And some children have a strong preference for expository nonfiction. Because these fact-loving kids are more interested in data, statistics, ideas, and information than in making an emotional connection with the central figure in a book, they will only thrive as readers if they are given access to a rich, diverse selection of expository nonfiction.

If you serve students in a library or teach, this is a must-read.

(Image from Understanding–and Teaching–the Five Kinds of Nonfiction, by Melissa Stewart in School Library Journal)