Public Domain - Copyright does not last forever. The main purpose of copyright law is to allow creators of works to be reasonably rewarded for their creative efforts. To that end, there are statutory rules to determine when copyright protection of a work comes to an end. In Canada copyright lasts for the life of the author, the remainder of the calendar year in which the author dies, plus 50 years following the end of that calendar year - the "life plus 50 rule". When the term of copyright expires, the work is said to come into the public domain and is then available for anyone to use and copy without seeking permission from the copyright owner. The author retains no rights in the work. This is the reason that Dickens' books, Shakespeare's plays, and Beethoven's symphonies are no longer protected by copyright.
Copyright in publications with multiple authors lasts until December 31 of the 50th year after the last author dies. Different rules apply to performer's performances, sound recordings and communication signals. See A Guide to Copyright for more information about the public domain in Canada.
Works can also be in the public domain because the work was not eligible for copyright protection in the first place or because the copyright owner has forfeited copyright in the work to the public. This can be done by stating on the work that it may be copied or reproduced without permission or payment of royalties. Restrictions can be placed on the uses that can be made of works in this case.
Open Access materials generally allow readers to view, download and copy the material freely for any lawful purpose. However, before using any open access materials check to see if there are any limits to the use of the content. The terms are set by the individual creator or copyright owner and can range from unrestricted use to partial access. Some online sources to find the open access content that is right for your course include the Directory of Open Access Journals (DOAJ) and the Directory of Open Access Repositories (OpenDOAR).
Creative Commons (CC) is a non-profit organization dedicated to making it easier for individuals to share and build on the work of others. It provides a number of licences for copyrighted content that are standardized and communicate clearly what type of use the creator grants to users and what rights they wish to reserve. Information on the different types of licences and attribution requirements are provided on the Creative Commons site.
Links to online resources that are Public Domain, Open Access and Creative Commons content can be found here.