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A. Dance / C. Music · Music and Dance

Music: Major and Minor Triads

C1.2 C1.3 C1.5 C2.2About 45 minutes
Learning goals
  • I can build major and minor triads by counting half steps.
  • I can change a major triad into a minor triad by lowering its third.
  • I can name the major and minor chords in a major key using Roman numerals.
  • I can use major and minor chords on purpose to create an effect in a short composition, and explain my choices with musical terms.

Words to know

triad
A chord of three notes stacked in thirds: root, third and fifth.
root
The bottom note of a triad, which gives the chord its name.
major triad
A triad with 4 half steps from root to third, then 3 half steps from third to fifth.
minor triad
A triad with 3 half steps from root to third, then 4 half steps from third to fifth.
chord quality
Whether a chord is major, minor or another type.
homophony
A texture where one melody is supported by chords.

Remember from Grade 6

In Grade 6 you built triads (root, third, fifth) and used the I, IV and V chords, which are all major in a major key. You also counted half steps to name major and minor 3rds.

This year you'll learn the difference between major and minor triads, and use both to create effects in your own music.

Major and minor: it's all in the middle note

Every triad has a root, a third and a fifth. The root and fifth are always 7 half steps apart (a perfect 5th). What changes is the middle note.

  • Major triad: root → third = 4 half steps (a major 3rd), then third → fifth = 3 half steps.
  • Minor triad: root → third = 3 half steps (a minor 3rd), then third → fifth = 4 half steps.

To turn a major triad into a minor triad, lower the third by one half step. C major (C E G) becomes C minor (C E♭ G).

Many listeners hear major chords as bright and minor chords as darker or sadder, but that is not a rule: lots of happy dance music is in minor, and the effect depends on tempo, rhythm and instruments too.

C major: C, E, GC minor: C, E♭, GC to E = 4 half stepsE to G = 3 half stepsC to E♭ = 3 half stepsE♭ to G = 4 half steps
On a keyboard: C major uses C, E and G (4 half steps, then 3). C minor uses C, E flat and G (3 half steps, then 4).
C majorC E GC minorC E♭ GG majorG B DG minorG B♭ D
Major and minor triads in treble clef: C major (C E G), C minor (C E♭ G), G major (G B D) and G minor (G B♭ D). Only the middle note changes.

Chords in a major key

If you build a triad on every note of the C major scale, using only notes from the scale, you get a mix of chord qualities. Musicians write major chords with capital Roman numerals and minor chords with lower-case numerals.

Scale noteTriadQualityRoman numeral
CC E GmajorI
DD F Aminorii
EE G Bminoriii
FF A CmajorIV
GG B DmajorV
AA C Eminorvi
BB D Fdiminished (3 + 3 half steps)vii°
The triads in C major. The same pattern (I ii iii IV V vi vii°) works in every major key.

Using minor chords in your music

Adding minor chords gives you more colours. A progression that many pop songs use is I – V – vi – IV. In C major that is C – G – Am – F. ("Am" means A minor.)

When chords support a melody, the texture is called homophony: one main tune with chordal accompaniment, like a singer with a guitar.

Worked example

Example: Let's build triads by counting half steps

Build a D major triad, then change it to D minor.

  1. Start on the root: D.
  2. Major third: count up 4 half steps: D♯, E, F, F♯. The third is F♯.
  3. Fifth: count up 3 more half steps from F♯: G, G♯, A. The fifth is A. (Check: D to A is 7 half steps.)
  4. D major = D F♯ A. For D minor, lower the third by a half step: F♯ → F.
  5. D minor = D F A. Check: D to F is 3 half steps, F to A is 4.

D major = D F♯ A. D minor = D F A.

Worked example

Example: Let's compose with major and minor chords for a purpose

Your class is making a 30-second video about the first snowfall of the year. The teacher wants music that starts calm and a little mysterious, then turns joyful when kids run outside. Let's plan 8 bars of chords in C major.

  1. Mysterious start (bars 1–4): use minor chords with a slow tempo and soft dynamics (p): Am – Em – F – G.
  2. Joyful ending (bars 5–8): switch to major chords, louder (f), with a bouncy rhythm: C – F – G – C.
  3. Melody: over the chords, play a melody that uses notes from each chord, so it fits. Ending on C sounds finished.
  4. Explain with musical terms: The minor chords, p dynamics and slow tempo create a quiet, mysterious mood. The change to major chords, f dynamics and faster rhythm creates excitement.

Bars 1–4: Am Em F G (minor, slow, p). Bars 5–8: C F G C (major, bouncy, f). The chord qualities, dynamics and tempo work together to match the video.

Just for fun

What did the C major chord say to the C minor chord?

“Cheer up! You’re only a half step away from being me.” 🙂

Hands-on activity

Major or minor?

You need: a keyboard, keyboard app, ukulele or guitar if you have one (otherwise, sing the notes), and paper and a pencil.

  1. Play or sing C E G, then C E♭ G. Describe each in one word.
  2. Ask a family member to play either a major or a minor triad while you close your eyes. Can you tell which? Keep score out of 10.
  3. Play the progression C – G – Am – F four times. Hum a melody over it.
  4. Compose 8 bars for a purpose: a theme song for a family podcast, music for a birthday video, or music for a short video about a rainy day. Write the chord names over 8 boxes.
  5. Perform it and explain why you chose major or minor chords where you did.

Your turn

1

How many half steps are between the root and third of a major triad? A minor triad?

2

Build an F major triad.

3

Change F major to F minor.

4

Build an E minor triad.

5

In C major, which chords are minor?

6

What does the lower-case Roman numeral vi tell you?

7

Write the progression I – V – vi – IV in C major.

More practice: warm-up

1

How many notes are in a triad?

2

What are the three notes of a triad called?

3

Name the notes of C minor.

4

Which note changes when a major triad becomes minor?

5

What is the Roman numeral for the major chord on the 5th note of a major scale?

More practice: on your own

1

Build A major, and explain how you found the third.

2

Is G B♭ D major or minor? Show why.

3

Name the vi chord in G major. (Scale: G A B C D E F♯.)

4

A composer wants a calm, gentle lullaby. Name two elements besides chord quality that would help.

5

Why do root and fifth stay the same when a triad changes from major to minor?

Challenge

1

Build all the triads in G major and label each with a Roman numeral and quality.

2

Analyse this progression in C major: Am – F – C – G. Which chord is the home chord, and what effect does starting on Am have?

3

Plan a 4-bar composition for a short scene where a lost dog is found. Use at least one minor and one major chord, and explain using musical terms.

Check your understanding

Quiz

1.

A major triad has ___ half steps from root to third.

2.

To change a major triad to minor, you ___.

3.

Which triad is minor?

4.

In C major, the chord on the 6th note is ___.

5.

D F♯ A is ___.

6.

A melody supported by chords is called ___.

7.

In both major and minor triads, root to fifth is ___ half steps.

For parents and teachers

Big idea: Grade 7 harmony focuses on major and minor triads. Students apply the elements of music for specific effects (C1.2), create compositions for specific purposes and audiences (C1.3), use notation (C1.5), and analyse, using musical terminology, how the elements are used (C2.2).

How to help at home:

  • A free keyboard app is the easiest way to count half steps.
  • Play "major or minor?" by ear with any instrument, or with chord sounds in an app.
  • Ask your child to explain why their composition uses minor chords in one place and major in another.

Common difficulties:

  • Counting the starting note as a half step. The first half step is the next key.
  • Saying minor always means sad. Encourage "often sounds darker", and listen to examples that break the rule.
  • Forgetting key signature sharps/flats when building chords in a key. Write the scale first.