Year 9 Music · Making Music — Compose and Perform · 10m read

Keys, Intervals and Tonality

Keys give music its home base. Understanding keys and intervals helps you read, write and analyse music more deeply.

Learning objective: Identify major and minor keys and intervals.

By the end of this lesson you can:

• I can read key signatures.
• I can name intervals.
• I can hear major vs minor tonality.

A key is a home base. Every key has a home note (the tonic) that melodies wander away from and return to — like leaving home for school and coming back at the end of the day. The key signature tells you which "streets" (sharps or flats) are on the route.

Keys, Intervals and Tonality

KEY SIGNATURES:
• Sharps or flats at the start of the stave.
• G major: 1 sharp (F#). F major: 1 flat (Bb). D major: 2 sharps.

RELATIVE MINOR:
• Shares a key signature with a major key: A minor ↔ C major; E minor ↔ G major.

INTERVALS:
• Distance between two notes: 2nd, 3rd, 4th, 5th, octave.
• Major and minor thirds create major and minor sounds.

TONALITY:
• Major (bright), minor (darker), modal, atonal.

| Key | Sharps/flats | Relative minor |
|---|---|---|
| C major | none | A minor |
| G major | F# | E minor |
| D major | F#, C# | B minor |
| F major | B♭ | D minor |
| B♭ major | B♭, E♭ | G minor |

Key ideas at a glance

• Order of sharps: F C G D A E B ("Father Charles Goes Down And Ends Battle").
• Order of flats: B E A D G C F — the reverse.
• Relative minor: Count down three semitones from the major tonic.
• Check the ending: The final note often reveals major vs minor.

Worked example (Medium)

A piece has one sharp and ends on E. What key is it likely in?

1. Key signature. One sharp → G major or E minor.
2. Ending. Ends on E.

Answer: E minor.

Worked example (Medium)

Find the relative minor of D major.

1. Tonic. D.
2. Down 3 semitones. D → C# → C → B.
3. Answer. B minor (same two sharps).

Answer: B minor.

Common mistakes

• Ignoring the final note It helps identify major vs relative minor. Fix: Check the ending.
• Counting the wrong way for relative minor Going up gives the wrong key. Fix: Count DOWN three semitones.

Modes — the colours between major and minor

Before major and minor dominated, medieval music used modes. Play all white notes from different starting points:

• Dorian (D to D): minor but brighter — used in folk and jazz.
• Mixolydian (G to G): major with a flat 7th — common in rock.
• Phrygian (E to E): dark, Spanish flavour.

Film composers and rock guitarists use modes to create moods that plain major or minor can't.

Practice questions

1. The relative minor of C major is:

   1. E minor
   2. A minor
   3. D minor
   4. G minor

   (1 marks)

2. How many semitones in a perfect fifth?

   (2 marks)

3. How many sharps are in D major?

   1. 1
   2. 2
   3. 3
   4. 0

   (1 marks)

4. The relative minor of F major is:

   1. A minor
   2. D minor
   3. E minor
   4. G minor

   (1 marks)

5. A melody uses F# and ends on E. Name the likely key and justify.

   (2 marks)

Summary

• Key signatures show the key.
• Relative major/minor pairs.
• Intervals measure distance.
• Learn the order of sharps and flats.