What is Fair Use?

I'm an educator - who's been out of the field for some time now. Copyright is a big scary word to some educators. To others, they choose to pretend it doesn't exist. I think many educators have the 'don't ask, don't tell' policy going on. To be honest, I don't really know much about it. I mean, I know there is the Copyright Law. But how does that really affect me? I'm not sure. I know there's a 'fair use' part of the Law, but what is the definition of fair use? I'm on a mission to find out! My first stop - Copyright Law Section 107 aka "Fair Use".

Ah ha! My first clue - there are several purposes that are deemed "fair" for use of the reproduction of a piece of work. I see teaching as one of the purposes. Does that mean educators are off the hook? Not so fast, my eyes skim further down the text. There are fear factors - no, wait, four factors that act as a test to determine if a use is fair.
1. For what purpose is the work to be used?
2. What is the nature of the work to be used?
3. How much of the work is to be used?
4. How will use affect the market value (present or future) of the work?

My work is not done - I must find out more! Until next time my friends.