76 K-8 Science Passages to Teach Reading Comprehension

The non-profit ReadWorks is addressing the nation's reading comprehension challenge by giving teachers the research-proven tools and support they need to improve the academic achievement of their students. ReadWorks provides research-based units, lessons, and authentic, leveled non-fiction and literary passages directly to educators online, for free, to be shared broadly. The ReadWorks curriculum is aligned to the Common Core State Standards and the standards of all 50 states. Most importantly, ReadWorks utilizes the most effective research-proven instructional practices in reading comprehension.

The ReadWorks database includes 76 science passages for grades K-8.  You can review the topics of the passages at: http://www.readworks.org/brand-new-science-passages.  Note that you will need to create a free account to access the units.