Visionlearning.com is a set of peer-reviewed science modules containing readings, interactive multimedia, and a glossary. The modules are available in both Spanish and English. The library contains modules in Biology, Physics, Chemistry, Process of Science, Scientific Research, and more.
Click HERE to see an example module: States of Matter
Applications for Science Teachers: This site is designed to support learners at the middle school and secondary level. The short is well written and supported by images, links, questions, and a quiz. The site contains a MY CLASSROOM feature to create a personalized online classroom. I can imagine linking some of these modules into a classroom blog or using them as homework/supplements to instruction also.