Teachers have long understood and enforced plagiarism. Yet teachers often ignore copyright laws, especially when working with the internet. Teachers assume, often incorrectly, that copyright laws do not apply to them as an educator. This might be right, but it might be wrong. It really depends on several things. Fair Use is a confusing legal term of art, often misunderstood. Public Domain is another confusing concept, especially concerning plagiarism.
Teachers need to model legal and ethical concerns when publishing websites and classroom materials. To model properly, we need to understand this area of the law, and follow it. Copyright law can seem punitive, limiting to creativity and innovation in teachers and students. There are ways to be creative and still respect copyright laws, just like there are ways to quote Seneca or Shakespeare in a paper to avoid plagiarism.
The Electronic Frontier Foundation has a complete curriculum on teaching students a balanced approach to copyright laws at https://www.teachingcopyright.org/
Copyright laws do apply to teachers and students. There are a few exceptions like when the use falls under fair use, and when the work being copied is in the public domain. Don't be tricked by the term "Fair Use." Fair Use is a legal term, which means courts have written a lot of opinions on what is and is not fair use. Generally, fair use does not mean copyright laws do not apply to teachers and students just because the copying is used for educational settings.
Plagiarism is when a person lifts another's work and claims it as their own, without attribution. Teachers are used to teaching students about plagiarism and how to avoid it in student writing and productions. Teachers teach how strong writers can use direct quotations to strengthen a paper. This is the concept of attribution.
Fair Use means a person can legally uses a piece of a copyrighted work. Not all works are copyrighted and that confuses teachers and students alike. There are four main factors courts look at when they judge one use a "fair use" and another use as "a copyright violation" -- purpose, nature, amount, effect on value.
Not all works are copyrighted and that confuses teachers and students alike. First, copyrights do not last forever. Second, copyright holders might want to put a work into the public domain. Works in the public domain should still be attributed to avoid plagiarism.
I am a teacher and a lawyer. As such, I felt it important to remind the reader that this is not legal advice. This content does not create any client-attorney relationship. This information is my opinion only, and may or may not reflect the opinion of any of my employers, including but not limited to my school employer, Dekalb County School District ("DCSD").