Are there really only 84 scales?

A chromatic scale has all 12 pitches, but if we want to make a "standard"(?) 8-note scale, we need to choose. So how many ways are there to choose 8 notes from the 12 pitches, or to say it another way, how many different "interval patterns" are there?

Turns out there are exactly 7 ways. If we start with the "major" interval pattern, W-W-H-W-W-W-H, we can rotate it 6 times: W-H-W-W-W-H-W; H-W-W-W-H-W-W, etc. Each of those interval patterns is called a "mode," and they have crazy Greek names. But more on that later.

So for any given mode, or interval pattern, we can start with any of the 12 pitches (or "roots,") so we have 12 * 7 = 84 possible 8-note scales.