Major Scales and Key Signatures
Senior 2 · Music
Major Scales and Key Signatures
Lesson 1 of 5
18 min
Listen to a school choir rehearsing for a competition, or a church choir before a service. The leader plays or hums one note and names the key of the song, and the singers know which notes to use. To understand keys you need two ideas first: the size of the steps between notes, and the signs that change a note, called accidentals.
A pitch is how high or low a sound is. Western music names pitches with seven letters, A B C D E F G, and then starts again. The distance from one C up to the next C is called an octave.
A piano or church keyboard lays out every pitch in order from low (left) to high (right). The white keys carry the seven letter names. The black keys come in groups of two and three, and C is always the white key just to the left of a group of two black keys.
A semitone is the distance from one key to the very next key, black or white, with nothing in between. It is the smallest step in Western music. A tone is two semitones.
Worked example
Is C to D a tone or a semitone? Move one key at a time: C to C♯ is one semitone, and C♯ to D is a second semitone. Two semitones make a tone, so C to D is a tone.
Now try E to F. There is no black key between them, so E to F is only one semitone. The same is true of B to C. These are the only two pairs of neighbouring white keys that are a semitone apart. Every other pair of neighbouring white keys has a black key between it, so it is a tone apart.
An accidental is a sign that raises or lowers a note, or cancels an earlier change. On the staff it is written just before the note head, on the same line or space as the note. In words it comes after the letter: we say "F sharp", even though the sharp sign is printed before the note.
| Sign | Name | Effect |
|---|---|---|
| ♯ | sharp | raises the note by one semitone |
| ♭ | flat | lowers the note by one semitone |
| ♮ | natural | cancels a sharp or flat, so the plain letter note is played |
| a bold x | double sharp | raises the note by two semitones (a tone) |
| ♭♭ | double flat | lowers the note by two semitones (a tone) |
An accidental lasts until the next bar line. If F♯ appears early in a bar, every later F on the same line or space in that bar is also F♯, unless a natural sign cancels it. The bar line cancels it automatically.
Every black key has two names. The key between C and D is a semitone above C, so it can be called C♯. It is also a semitone below D, so it can be called D♭. Notes that sound the same but are written differently are called enharmonic notes. White keys can have second names too: E♯ is played on the key usually called F, and C♭ is played on B. Which name you write depends on the letter the music needs, as you will see when you build scales in the next lesson.
Tip
Find the gaps. Where two white keys have no black key between them (E–F and B–C), the step is a semitone. Everywhere else, neighbouring white keys are a tone apart. Sharp goes up, flat goes down, natural goes back to plain.
Try each question first, then check the worked solution underneath.
Name the note one semitone above B.
Solution: C. There is no black key between B and C, so the very next key up is C.
How many semitones are there from C up to E?
Solution: Four: C to C♯, C♯ to D, D to D♯, D♯ to E. Four semitones make two tones.
Give the other name of G♯.
Solution: A♭. The black key between G and A is a semitone above G and a semitone below A.
A bar contains F♯, and later in the same bar an F with no sign in front of it. Which note is the second F?
Solution: F♯. An accidental lasts until the bar line, so the sharp still applies.
Which key is played for E♯?
Solution: The white key F. E♯ is one semitone above E, and the very next key above E is F.
Remember
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