U.S. Copyright law is Title 17 of the U.S. Code, and Section 110a defines a specific exemption for performance and display of copyrighted materials in a face to face classroom environment. It is actually a very simple exemption:
Faculty customarily hand out copies of articles and chapters for classroom use, but this is not allowed under U.S. Copyright law. Why? Educational Use covers only performance and display, but making handouts means you're distributing copies.
If you want to make hand outs, that has to fit in under Fair Use. Unfortunately, as we will discuss later, Fair Use does not usually stretch as far as whole articles or whole book chapters being used term after term. Fair Use covers only handouts that contain brief excerpts.
The best thing to do is take advantage of the Internet, and have students access the articles (on the web or in library databases) on their own. They can bring it to class on a laptop or mobile device, or they can even print a personal copy to bring to class. Yes, the same thing is being read by the same number of people, but to the law, it makes a difference whether students print personal use copies (ok) or the instructor distributes copies (not ok.)
Consult with your students at the beginning of the term to determine whether they have the technology and skills they will need for accessing readings at home and in class, and make accommodations if they do not. This can be part of your syllabus review. Make sure that your face-to-face students have easy access to computer labs, wireless Internet, and printers in the building, and time to use them. In a pinch, even if they have to direct you to make them a print-out from your office computer, that still counts as their personal copy.