Guitar scale?

If you go around asking people to sing, you find that they all use the same notes but in different sequences. Some Chinese and American Indian music uses the pentatonic scale of five notes, like this:

https://www.youtube.com/watch?v=o83xxWCel8g

Most Europeans and Americans will sing a scale of eight notes. But some people have higher or lower voices, so you discover that they all sing eight out of the same twelve notes, generally using the same order of notes: three whole steps and two half steps. So there you have twelve scales that all sound the same even though the actual notes are different.

That's as far as I ever got in music theory. There is a LOT more to learn.

Here is a site dedicated to Hawaiian guitar scales: http://dancingcat.com/

The Hawaiians developed 62 different ways to tune a guitar, all of them below standard tuning. They call their style "slack key".

SmartAz gave a good technical question but I'm guessing you are still a little confused as to how this relates to your guitar playing. Understand that what I'm about to say is an over simplification of what a scale is. But I feel it is an appropriate explanation for a beginner wanting to know how they apply it to guitar.

So here goes... A scale is your road map to playing lead. So when you see a guy ripping a lead, the notes he is playing aren't random, they are determined by the scale, or scales, he is using. The way most all instructors teach scales is by finger patterns. But many self taught guitarist just kind of learn by trial and error.

So let's take the most simple scale of all, the minor pentatonic. There are 5 notes in this scale and 5 positions of this scale. The different positions are what allows you to play lead all over the neck. So here is how we find the first, or root, position. You need to know what key the song is in, many times that is the first chord but it is easily looked up if you aren't sure.

So let's say the song is in the key of A and we want to play lead using the A minor scale. You simply find the A note on the 6th (fattest) string. So that would be the 5th fret...right? You put your index finger on that position (6th string, 5th fret). Now the pattern you play is this, 6th string - 5th fret, 8th fret; 5th string - 5th fret, 7th fret; 4th string - 5th fret, 7th fret; 3rd string - 5th fret 7th fret; 2nd string - 5th fret, 8th fret; 1st string - 5th fret, 8th fret.

You will be playing any note on the 5th fret with your index (first finger), and note on the 7th fret with your ring (third finger) and any note on the 8th fret with your pink (fourth finger). So now we can turn this into a finger pattern. Starting at the sixth string, the finger pattern would be 1-4, 1-3, 1-3, 1-3, 1-4, 1-4. By thinking of a finger pattern rather than frets, you can move this to any key on the neck. So if the song was in B rather than A. You would just start that pattern on the 7th fret instead of the 5th, because the 7th fret of the 6th sting is a B note.

Now there are 4 other finger patterns you would need to learn as well to play all over the neck in one key. But hopefully this helps you understand why I call scales a rod map, because that literally is the case as you can see.

Are you asking about scales - like musical scales (a C major scale is CDEFGABC) or are you thinking of "scale length" as it relates to guitar? Or are you using the word in some other way?

I thought at first you meant musical scales but you used the word "scale" (without the "s") three times.

If you mean "musical scales" then they are just sequences of notes relating to specific keys. Really, if you need to ask you're not going to undrstand the explanation. You need to learn the basics of music. The idea of "a scale" is one of the first things you'll come across.