A professor has an article to share with students class on Canvas. Is it considered to be in violation of copyright?
No, fair use allows the professor to share it on Canvas with his one classes for a one time (semester) use. If the professor planned on using it for more than one semester, the professor would need to seek permission for use.
Can a professor just give the citation of an article for the students to find?
Technically yes. However, unless the full-text article in available in the databases, the library will end up paying for copyright each time a student requests the item (depending on the age of the article). It would be best for the professor to request permission to the use the article and pay the one-time copyright fee.
A professor just wants to copy a chapter in a book for use in class. Is that considered in violation of copyright?
This question falls under section 3 of fair use. The amount of work allowed under fair use is proportional to the length of the entire work. The general rule of thumb is using less than 20% of the work is considered fair use.
The Technology, Education, and Copyright Harmonization Act (TEACH Act):
In order to qualify educators must meet these requirements: