PBS Teachers is a wonderful site with lots of resources and supplemental material for teachers to use with students. This particular link will take you directly to the STEM education resource center: Professional Development and the focus on this page is Global Climate Change Modules from PBS and NASA. However, if you look at the top of the page you can choose a specific grade band and then within that there are various content areas that can be chosen. Looks like a very interesting site with lots of resources to select from.
The National Science Digital L ibrary is the nation's online libdrary for education and research in science, technology, engineering, and mathematics. It provides free math lessons and activities aligned with the Math Common Core Standards, as well as STEM-related blogs and other free teacher resources and lesson plan ideas. Targeted for K-12 teachers, higher-education professionals, and librarians, NSDL also provides science literay maps and ITunes multimedia files.