What is Public Domain?
When the term of copyright for a work expires, the work becomes part of the public domain. This means that the work is no longer protected under the Canadian Copyright Act and can be used freely without getting permission or providing payment to the copyright holder of the work.
In Canada, copyright for a work generally exists until 50 years after the end of the calendar year of the author's death. There are exceptions and different types of works where entry in the public domain could be later.
Creators may also choose to "donate" their original creative works to the public domain. In doing so, creators waive the copyright to their work allowing others to freely use and/or adapt the work.
Note: Although you may freely use public domain materials, it is good academic practice to provide attribution (e.g., citation) to the work.
What is Creative Commons?
"The Creative Commons copyright licenses and tools forge a balance inside the traditional 'all rights reserved' setting that copyright law creates. [Creative Commons] tools give everyone from individual creators to large companies and institutions a simple, standardized way to grant copyright permissions to their creative work." (Source)
What are Open Resources?
Open resources are online materials that are free to view and/or use.
Open resources are different from public domain materials since creators generally retain copyright of their works.
Creators of open resources have the ability to define how they want their works to be used through open licenses. Compared to traditional copyright, these licenses provide users more flexibility to share and build upon creators' works. An example is Creative Commons licensing.
Icon: Padlock by Fahmihorizon from the Noun Project
What are Open Educational Resources (OERs)?
"…any type of educational materials that are in the public domain or introduced with an open license. The nature of these open materials means that anyone can legally and freely copy, use, adapt and re-share them. OERs range from textbooks to curricula, syllabi, lecture notes, assignments, tests, projects, audio, video and animation." (Source)
For more information, see Seneca College Faculty Guide to OERs.
Icon: ebook by Vectors Market from the Noun Project