Half steps, whole steps and the major scale
Measure distances on the keyboard in half and whole steps, then use one pattern, W W H W W W H, to build a major scale from any note.
A PUZZLE
Why does do-re-mi only work from C?
Play the white keys from C up to the next C and you hear the familiar do re mi fa sol la si do. Now play eight white keys starting from D instead. Same kind of keys, but the tune comes out different, a bit darker. The white keys did not change. The distances between them did. This lesson gives you the ruler.
Remember from last lesson: E–F and B–C have no black key between them. Start from a different white key and those two tight spots fall in different places in your eight notes.
Half step and whole step
A half step (semitone) is the distance from any key to the very next key, black or white. It is the smallest step on the keyboard. A whole step (tone) is two half steps: you skip exactly one key.
C to C# is a half step. E to F is also a half step, because no key lies between them. C to D is a whole step (C# is skipped). E to F# is a whole step (F is skipped).
Check yourself
Half step or whole step?
- E to F
- C to D
- B to C
- F to G
- A to Bb
- E to F#
Show the answer
Half step: E to F, B to C, A to Bb
Whole step: C to D, F to G, E to F#
THE PATTERN
The major scale
A scale is a ladder of notes climbing from one note to its octave. The major scale is the do-re-mi ladder, and its rungs are spaced in a fixed pattern of whole steps (W) and half steps (H): W W H W W W H. Seven steps, eight notes, and the last note is the first one again, an octave higher.
Say it in two halves to remember it: "whole whole half", then "whole whole whole half". Each half ends with the tight step.
Build C major: start on C and follow the pattern.
C D E F G A B C
W W H W W W H
In half steps:
2 + 2 + 1 + 2 + 2 + 2 + 1= 12 half steps, exactly one octave.
C major = C D E F G A B C, all white keys.Look where the two H steps fell: on E–F and B–C, the two places with no black key. That is why C major needs no black keys at all, and why do-re-mi "just works" from C.
Check yourself
Nika plays eight white keys in a row from D up to D and says, "That's D major." Is she right?
- Yes, any eight white keys in a row make a major scale
- No. Her second step, E to F, is a half step where the pattern needs a whole step
- Yes, because she starts and ends on the same letter
- No, because major scales never start on D
Show the answer
No. Her second step, E to F, is a half step where the pattern needs a whole step
Exactly. D–E is a whole step, but E–F is only a half step. The pattern wants W W, so the third note has to be F#, not F.
Build G major by the pattern
- W W H: G → A → B → C
G to A and A to B are whole steps. B to C is the natural half step. So far, all white keys.
- W W: C → D → E
Two more whole steps, still white keys.
- W: E → ?
The pattern wants a whole step, but E to F is only a half step. Go one key further: F#.
- H: F# → G
F# to G is a half step, and you are home, one octave up.
G A B C D E F# G
W W H W W W HG major = G A B C D E F# G
One black key: F#.Sing "do re mi fa sol la si do" starting from a higher note than usual. Same tune, moved up. The pattern IS the tune. The starting note only decides how high it sits.
Check yourself
C major and G major sound like the same do-re-mi tune, only starting from a different pitch.
Show the answer
True
True. Both follow W W H W W W H, so the shape of the tune is identical. G major simply sits higher (or lower), and needs F# to keep the shape.
Check yourself
Omid builds F major. He has F, G, A and now needs the half step. What is the fourth note?
- Bb
- A#, the key right after A
- C, because B and C are close together
- B, the next white key
Show the answer
Bb
Yes. A half step above A is the black key, and because the letter B has not been used yet, it is spelled Bb. F major = F G A Bb C D E F.
A stencil you slide along the keys
Think of W W H W W W H as a stencil with eight holes. Lay its first hole on any key and the other holes show you the rest of that major scale. Slide it to a new key and it picks a new set. Where the analogy breaks: a stencil looks the same wherever you put it, but under your fingers every scale is a different mix of black and white keys. They sound alike and feel different.
Check yourself
- C major: C D E F G A B C, no black keys
- D major: D E F# G A B C# D, two black keys
Both are major scales and both sound like do-re-mi. What is the same in the two?
- The number of black keys
- The order of whole and half steps
- The starting note
Show the answer
The order of whole and half steps
Right. Both are W W H W W W H. D major needs F# and C# only to keep that order of steps.
Why this matters
- When someone says a song is "in G major", they mean it is built mainly from these seven notes, with G as home.
- That is why one particular note can sound wrong in a song: it is often a note from outside the scale.
- There are 12 possible starting notes, so there are 12 major scales, all made with the same pattern.
Lesson recap
- A half step is the very next key; a whole step is two half steps.
- The major scale follows W W H W W W H, which adds up to 12 half steps, one octave.
- C major is all white keys because the half steps land on E–F and B–C.
- From any other note you need black keys to keep the pattern: G major has F#, F major has Bb.
- Each letter appears once in a scale, which decides between a sharp name and a flat name.