How to Build Scales

This is a 9.23 minute video response from Mark Lincoln on Aug 28th, 2009

Question:

"Walter_Mundstock asked "Hi Guys. First of all, I have joined JamPlay a few days ago and I have to say that you guys do an AMAZING job. I wanted to stay at home to be with my recently born daughter and didn't want to quit having guitar classes... JamPlay met perfectly my needs! Thanks guys! I have been having classes about scales, have been practicing and memorizing them, but I would like to understand a little better how these scales are built. I would like to be able to think about any note and build the scale for that key by myself. An exercise I have been doing is to listen to songs, identify its notes and build the scale by applying the WWHWWWH steps. That usually get me setup with something that seems quite right... Is there a "formula" to build pentatonic and other scales just like I'm doing ? Apart of that, I don't really understand what is the difference among a chromatic scale, diatonic scale and so many others... Please help me understand the context of these scales. Thanks. Walter.""