SCALES!!

What are the difference between G major scale and E minor scale?The notes are the same,how can i define them?

Well, they are the same note so they are said to be in the "same key" (Generally keys are named by the major scales they contain) or to be from the same "Parent scale". I prefer the term "parent scale" because some of the scales I play are not based on Major keys.
E Minor and G Major have the same notes so which of these you are playing in depends upon what the highest and lowest notes of your tune are or where the passage comes to a rest (on the E or G), the natural resting place of a passage is called it's tonic note. E minor and G major are said to be different Modes of the same key, that is to say that they contain the same notes but start at different places. Sometimes it's not clear which mode one is playing in because the melody spans more than one octave. Confused? You will be, there are tons of threads on this site about modes and they don't seem to come to anything but a vague consensus. Still, hope this helped.

It's the tonality of what your playing. A tonality is the impression of the music your playing, like sad, happy, angry, whatever. Tonality applies to all scales, and is mostly seen in exotic scales. Like a japanesse scale, well it's called the japanesse scale because it sounds japanesse. You can classify all scales by this, but not all scales are clear like that one (i.e. modes).

Going back to what you said, "how do I know if I'm playing in G major or E minor?". Try playing each as a chord, play a G major chord and then a E minor chord. Clearly you can tell one sounds minor and the other sounds major. This is how you can tell, very simple. You want to play something that is more minor in tone, then you would be playing in E minor. Looking for something alittle more happy (however you choose to classify major), you would be playing in G major.

Originally posted by Yb
how can i define them?

If the riff ends on an E then it's E min , if it ends on a G then it's G maj.

How do I define them? Define them through harmony. E B7 or G D7. I V7, the key to playing and paying life. Quite frankly, nothing else matters in between. The only difference between a G maj or E min is one note, D#. Major scales or pentatonic. Ironically, either one works in both. It's called savvy, balls or experience.

Originally posted by griphon2
The only difference between a G maj or E min is one note, D#.

D# doesn't exist in either of those scales bro. I think your thinking of E major instead of E minor. The difference is the texture of what your playing a certain riff in or chord progression. If your playing something that sounds minor then your playing in a minor key. If it's something that sounds major, it's in a major key. There is nothing hard about it, and they wouldn't have wasted time calling them different when they do have the same notes. This idea works whether or not the riff ends on the tonic. You could have a chord progression like II - VI - III - v. As you can see it doesn't end on the tonic but yet you can tell by playing it, it's minor. Just by it's sound.

[Edited by noticingthemistake on 04-15-2003 at 10:19 PM]

In reference to G D7 = G maj scale
In reference to Em B7= E harmonic minor to be technical. Or a G maj with a raised 5th. Can also play E melodic minor, which is an Emaj scale with a b3rd. I tend to look at scales in terms of function, not as actual scales themselves. It's quicker and easier for me. All these fancy scales meld together with and in time. I tend to play whatever fragment is needed at the moment. It's easier for me to string shorter concise phrases together than one long Berlioz line. My scale days are long gone. I rarely end lines or phrases on roots, especially improvising. It's just not my cup of tea.