The below video is a parody of Disney created by Professor Eric Faden of Bucknell University. It explains the U.S. copyright laws and the types of work that it protects such as music, film, dance, etc. It says that ideas can not be copyrighted. Only the form in which that idea is express is copyrighted. It talks about the duration of copyright and when a work goes into public domain when copyright expires. And finally it explains the copyright fair use doctrine.