National Science Digital Library – lesson plans and more
The National Science Digital Library is an excellent site that provides plenty of lesson plans, information on educational standards (including the Common Core), and Science Literacy Maps.
Their lesson plans are often available in multiple translations to support students in many languages. It was produced by funding from multiple grants from the National Science Foundation and through University Corporation for Atmospheric Research (UCAR) Community Program efforts.
You can find this site and many more highlighted on our Science Education research guide. This guide features key academic journals, free websites, and how to find books for science teachers at all levels.