Copyright is a major consideration when creating and using instructional media. If you use any media that you did not create yourself, you must seek permission to use it in a classroom or on a website. There are certain exceptions under the Fair Use Doctrine which allows media to be used for educational purposes as long as certain conditions are met. Works that are Public Domain may be used without infringing on copyright. These are works that have never had a copyright or that the copyright has expired. Creative Commons provides a platform to legally share works. Each contributor to Creative Commons decides how the work may be shared and which attributions must be included when the work is shared.
This is a list of websites and videos that will help you understand how media can be used legally in the classroom and online.
U.S. Copyright Office
PBS Copyright for Educators