Once you have a sound understanding of tones (whole tones) and semitones (half tones), then you can work out what the various scales are.
Major Scale – this scale has seven notes in it but when you play it on the piano you finish on the note you start just an octave higher. The pattern is always:
Between the first two notes is a tone, between the second and third note is a tone, between the third and fourth notes is a semitone, between the fourth and the fifth notes is a tone, between the fifth and sixth notes is a tone, between the sixth and seventh notes is a tone and between the seventh and eighth notes is a semitone.
So the abbreviated version goes tone, tone, semitone, tone, tone, tone, semitone.
An example of this is C, D, E, F, G, A, B and C which makes up the C major scale.
Natural Minor – this scale also has seven notes but you still play the first note again, just an octave higher. The pattern is always:
Between the first two notes is a tone, between the second and third notes is a semitone, between the third and fourth notes is a tone, between the fourth and fifth notes is a tone, between the fifth and sixth notes is a semitone, between the sixth and seventh notes is a tone and between the seventh and eighth notes is also a tone.
This time the abbreviated version goes tone, semitone, tone, tone, semitone, tone, tone.
A simple example of this scale is E natural minor which is E, F sharp, G, A, B, C, D and E.
Harmonic Minor – this scale is only slightly different to the natural minor and it still has seven notes with the first note repeated an octave higher. The pattern of tones and semitones is as follows:
Between the first two notes is a tone, between the second and third notes is a semitone, between the third and fourth notes is a tone, between the fourth and fifth notes is a tone, between the fifth and sixth notes is a semitone, between the sixth and seventh notes is a tone and a half, and finally between the seventh and eighth notes is a semitone.
The abbreviated version is: tone, semitone, tone, tone, semitone, tone and a half, semitone.
An example of this is E harmonic minor which is E, F sharp, G, A, B, C, D sharp and E.
Melodic Minor – this scale is a seven note scale like the others, but unlike the others it is slightly different going up (higher) than it is going down (lower).
On the way up between the first and second notes is a tone, between the second and third notes is a semitone, between the third and fourth notes is a tone, between the fourth and fifth notes is a tone, between the fifth and the sixth notes is a tone, between the sixth and the seventh notes is a tone and between the seventh and eighth notes is a semitone. The pattern going down is: between the eighth and seventh notes is a tone, between seventh and sixth notes is a tone, between the sixth and fifth notes is a semitone, between the fifth and fourth notes is a tone, between the fourth and third notes is a tone, between the third and the second notes is a semitone and between the second and first notes is a tone.
This can be abbreviated to tone, semitone, tone, tone, tone, tone, semitone, and on the way down; tone, tone, semitone, tone, tone, semitone, tone.
Here is an example of E melodic minor: E, F sharp, G, A, B, C sharp, D sharp and E then D, C, B, A, G, F sharp and E.
Pentatonic Scale – is a five note scale, but like the others, you would finish on the first note up an octave higher.
The pattern is: between the first two notes is a tone, between the second and the third notes is a tone and a half, between the third and fourth notes is a tone, between the fourth and the fifth notes is a tone, and between the fifth and the sixth note is a tone and a half.
The abbreviated version is tone, tone and a half, tone, tone, tone and a half.
The classic example of the pentatonic scale is playing all the black notes on the piano.
Whole Tone Scale – as the name suggests, it is entirely made up of tones and there are six notes in the whole tone scale.
An example of a whole tone scale would C, D, E, F sharp, G sharp and A sharp.
There are many other types of scales belonging to other music traditions but the scales listed above are the ones you will be using probably one hundred percent of the time.