Copyright
Confused about Copyright??
Copyright protects original works of authorship. It does not protect “ideas,” which is why the theme of alien invasion found in Independence Day can also be used in numerous other books, radio broadcasts, TV shows, movies, etc... Educators and students may use even copyrighted material if it meets “fair use” requirements.
One of the best quick explanations of fair use is found at Creativity and Copyright.
For more in-depth guidance, Xavier University has an excellent website.
And this website provides an excellent quick reference sheet (“Copyright and Fair Use Guidelines for Teachers”) that may be downloaded.