Alternation

There are two words that are easily confused.  One is alternatively, and the other is alternately.

If you have an arrangement where you meet in one location one week, a different location the next week, and back again to the first location the next week, and so on, you would describe it as meeting in those two locations alternately.  That's a clumsy example, but I guess it works. 

On the other hand, if you choose to do something one way, but have a different idea of how to do it, that's an alternative.  To do something alternatively is to do it in a different way.

Both words involve two ways of doing things, or more.  But—it seems to me, anyway—if you say alternately, it implies doing something repeatedly; one time one way, the next time, the other way.  This is called strict alternation.  The use of the word alternative simply indicates different available choices.

Kay