Copyright (C)--are laws protecting the exclusive rights to an original work (the expression of an idea, not the idea itself). The rights include the right to distribute, adapt, and copy the work. Once a work is created, it automatically falls under copyright protection. If a work is copyrighted, one would have to ask permission of the creator to use the work.
Creative Commons (CC)--is a license that allows the creator to retain certain rights for their work while also allowing that work to be shared and used by the public. Instead of "all rights reserved" CC changes the license to "some rights reserved."
Fair Use--is a law that allows for some limited use of copyrighted material (without the permission of the owner) only if the work is going to be used for teaching, reporting, parody, or criticism. And even then, there are strict guidelines to follow that consider the purpose of the work created, the nature of the original copyrighted work, how substantial the amount used is, and what effect the use of the work may create in the market.
Public Domain--works in the public domain are not protected by copyright laws (either by expiration or forfeit). In the United States, works fall into the public domain if after the life of the author plus 70 years OR 95 years from publication or 120 years from creation (whichever is shorter). FAQ for Public Domain
Creative Commons Search
Use this link to search for creative commons images, video, and music hosted by other sites
Here is a simple video on copyright that you may want to share with your students.