Okay, i've had some trouble understanding scales and keys lately, and i need you all to answer 2 questions for me.

question 1: can you play scales by each note as a root note? as in, can i play stuff like F C and D pentatonic all with the same shape with those certain notes as the roots, or is there a certain shape for every one of them?

question 2: Are keys just notes that you base the song or riff off of? like, say i play almost all of the song off of B-related scales, does that mean the song is written in B?

so, now it's your turn to tell me if i am either right or hopelessly confused!

p.s. sorry if i kinda made a huge wall of text.
1. Yes, the scale "patterns" are interchangeable.
2. I'm not sure what you mean. Can you clarify a little bit?
Question 1: Not the best with Theory but if you are playing a pentatonic shape I guess you can there is nothing written saying you can't. But each note in a progression has a mode related to it.

Ill go with C being it's the easiest key.

C D E F G A B C
1 2 3 4 5 6 7 8
M m m M M m º M

1: Ionian (Tonic) Is that correct term?
2: Dorian
3: Phrygian
4:Lydian
5: Mixolydian (Dominant)
6: Aeolian (Natural Minor)
7: Locrian (Diminished)

Each mode has a different pentatonic shape if you want I can send you them when I get time...

When you put all the modes together they make a Major Scale W W h W W W h.

Question 2: Key is the set of chords used in a song. Like in the key of C shown about you would have

C Maj Dm Em F Maj G Maj Am Bº. If you move one scale they all move which is a way to find out the notes in a key.

So to answer your question no it does not mean the key of the song is B

Can some theory expert read this and tell me if I suck or am I correct on this.

Oh yeah Hope this helped and send me a pm if you would like me to show you the pentatonic shapes and how they fit together!

Keep on Rockin man
Well coryklok, what i really meant to say was "what determines what key the song is in?" (i guess that i just ramble too much ), but Myung pretty much cleared that up. And Myung, I'll be sure to pm you sometime or later.
I'm no expert on theory, but I don't think there are 7 pentatonic modes.
And im really going out on a limb on this one, but since the major pentatonic is the major scale without the 4th or 7th degree, would that mean that the pentatonic scale does NOT have a lydian or locrian mode?
And I'm pretty sure that any scale shape can be moved around depending on the key you play it in.
I am a Rocker; I Rock out!
(Semicolons ftw)
Quote by Myung'sMusicman
Im a sure that there are only 5 pentatonic modes and you are correct Lydian and Locrian do not have a pentatonic mode.

The pentatonic scale doesn't really function modally. The major pentatonic scale (1,2,3,5,6) is missing the 7th degree for obvious reasons. If you play a major scale (Ionion) over a 7th chord, you get a tone conflict (b7 and 7). If you want to play the major scale over a 7th chord, you could use the mixolydian mode, but that's a different scale and different story.

The way I see the pentatonic scale, minor or major is a scale missing the degrees, which way you can play it over any chord, if not all. Modes do not apply to pentatonics.
I'm not quite sure what you're asking but I'll try and answer

Question 1:
If you know a pattern for the F major pentatonic, for example, then no you will not be able to play the D major pentatonic just by starting on the D. This is because different scales have different notes, so D pentatonic has different notes to F pentatonic.

Try and think of scales as notes, not shapes.

The major pentatonic scale is a major scale without the 4th or the 7th note. So the F pentatonic scale has the notes :

F G A C D

and the D pentatonic has the notes:

D E F# A B.

The pattern for the F pentatonic will only have those notes in it so if you started on D you would get:

D F G A C

which is obviously not what you want. What this means in terms of patterns is that there is a different pattern for each key, however this may just be different because it is somewhere else on the neck. However, scales exist all over the neck so there will be a lot of patterns for each one, which will all join up to form one huge pattern.

Question 2:
The key of a song can be either major or minor. The tonic of the key (the x in x major or minor) is the note that the song resolves on. This means that when you play the note the song sound finished. The major or minor comes from just listening to it to see if it sound major or minor (of course, theoritically it gets more complicated but that's a good way to find out the key).

However, if the key is B major then it will usually have lots of the notes from the B major scale because these notes sound major and resolve nicely to B (and B minor would be from the minor scale). There notes that are not from the B major scale in a song in the key of B major though.

So there are two main ways to find the key of a song. Either

A)Look at the notes and find which major and minor scales (there should be one of each). The determine which it is by if it sounds major or minor (or on which of the tonics it resolves on) .

or

B)Find which note it resolves on, the decide whether it's major or minor (or determine if most of the notes fit into the tonic's major or minor).

Hope this helped.