Khan Academy is popular in math for its brief lectures and interactive modules. However, you can also use it in the Social Studies. Check out Smarthistory, a free multimedia platform for student and teacher of history, archaeology, museum curation, and art history.
It includes an interactive timeline, in-depth yet easy to understand articles, vibrant images, and videos about topics throughout history and around the globe. Check out “Teach with Smarthistory” for ideas on how to incorporate it into your classroom. If you are a historian, archaeologist, museum curator, or otherwise involved in the social science consider contributing an article or multimedia content. Additionally, Smarthistory contributes videos to Google Art Project.