Spark & Anvil Privacy

Teach & case

Help a near-peer reason through the idea — when you explain it, you understand it best — then read the real decision it comes from.

A case · you decide

Aurelio and the chord that "sounds happy"

Aurelio — a student arranger labeling chords for the school band who keeps guessing quality by how each one "feels"

The idea in play: determining chord quality from the third (a major vs minor 3rd) rather than from how it "feels".

Aurelio is labeling chords in a score. One "sounds happy," so Aurelio writes major; another "sounds sad," so minor. But the conductor plays a bright, up-tempo minor chord that Aurelio swore was major, and a somber major chord in a slow passage that Aurelio called minor. Feel keeps misleading. What actually decides major vs minor?

Chord quality is fixed by the INTERVAL from the root to the third: a major 3rd (4 half-steps) makes it major; a minor 3rd (3 half-steps) makes it minor. That's a countable fact about the notes, independent of tempo, dynamics, or mood.

"Happy" and "sad" are how a chord is USED — tempo, context, the melody over it — not what it IS. A major chord in a slow, quiet passage can sound mournful; a minor chord at 160 bpm can sound joyful. The third tells you the quality; the arrangement tells you the feeling.

Aurelio hears a chord that feels upbeat and labels it major. How should Aurelio actually decide?

The conductor's minor chord sounded cheerful at a fast tempo. Does that make it "kind of major"?

Name a chord by its third yourself →

When two ideas meet: 2 cases with two people

A case · you decide

Caspar and Zinnia: a scale built from steps

Caspar & Zinnia — a student who measures intervals, and a friend who builds scales and keys

The idea in play: every major scale uses the same step pattern, whole-whole-half-whole-whole-whole-half, so the pattern decides which notes need sharps.

Zinnia wants to write out the D major scale. Caspar hands her the step pattern: W W H W W W H.

A whole step is two semitones. A half step is one.

From D, a whole step lands on E. The next whole step from E is not F, which is only a half step away.

Which notes are in D major?

Open the Ear Bench →

A case · you decide

Aurelio and Ottilie: the chord that sounds like an ending

Aurelio & Ottilie — a student who builds triads, and a friend who hears how progressions finish

The idea in play: a perfect cadence moves from the chord on the fifth note of the key (V) to the home chord (I); building V shows why it pulls home.

Ottilie's song in C major sounds unfinished at the end. Aurelio offers to build the chord that should come just before the last one.

A triad stacks alternate notes of the scale, and you can start one on any degree.

One note of C major sits a half step below C and pulls up toward it.

Which two chords make the strongest ending in C major?

Open the Ear Bench →