Copyright secures for the creator of a creative work the exclusive right to control making or distributing copies of a work, performing or displaying it or adapting it. Copyright does not protect ideas, thoughts or facts.
For more information on copyright, see:
Fair use ensures that there are some types of uses that do not require permission or payment based on four (or five) factors:
Purpose and character of the use
Nature of the copyrighted work
Amount and substantiality of the portion used
Effect of use on the potential market for the copyrighted work
For more information on fair use, see:
Chapter not an entire book, journal or newspaper article; chart, graph, diagram, drawing, picture more likely to be fair use.
Copying should occur closely in time to the need to use copies, should not be repeatedly such as multiple trimesters and permission should be obtained as feasible, also should not copy and use same material for several different courses. Making multiple copies of various works should not substitute for purchase of books or periodicals. Seek permission when you intend to use material for commercial purposes, plan to use the material repeatedly or when you want to use a work in its entirety. Always credit the source.
Classroom Use Exemption
Provides instructor and students broad rights to perform or display works but applies only to nonprofit, in-person, classroom teaching...not online.
T.E.A.C.H. Act (Technology, Education, and Copyright
Provides some rights for online and distance learning but is much more restricted and requires meeting a lengthy list of conditions.