When teaching science, the phrase “a picture is worth a thousand words” has never been more true.  Cool Science GIFs is a great place to find a repository of science gifs, videos, and illuminating explanations.  Subjects range from astrophysics to chemistry and everything in between.  This is a tumblr site, so be judicious when linking to it as sometimes the language on tumblr can be inappropriate for small children.  It is always possible to extract just the gif and post it to your ePortals though.

Website: http://coolsciencegifs.tumblr.com/
Subject: Science
Grade Level: 1-12
Price: Free