web address: http://nsdl.org/
NSDL is the National Science Digital Library. This is a repository of science content and learning. The site contains a wide variety of really useful information. One area referred to as refreshers is designed to help teachers do just that refresh their knowledge in an area they need help in. The resources often point to other websites and bring together everything from amateur YouTube videos, to professional peer reviewed journal articles.
The site is all free of charge and does not require a login so go explore some science.