Q. Can I show a film or video in my class?

Yes, you are allowed to show a full film or a portion of a film in a physical class setting (in-person/face-to-face) if the film is shown for educational purposes that match the course's curriculum. The copy you are showing or streaming must be a legally obtained copy and NOT from a streaming platform for which you have a personal license (like Netflix). 

What requires extra consideration is if the course is an online course, remote course, hybrid course, long distance course, or so on (ie a class that is broadcast to another location or is asynchronous). The TEACH Act may have exemptions that apply, but it is not as clear-cut of an issue. Fair Use might also apply in these scenarios. Ironically, academia tends to rely on Fair Use more than the TEACH ACT.  

What cannot be done is showing a copyrighted film to a group of students outside of a classroom setting, even on campus, without a license/permission. For this a classroom exemption would not apply. Even if for educational purposes, you will need to weigh all the factors of Fair Use.  

Please see the links below to more information in understanding this topic.