# Scales & Keys, Music theory

Half steps, whole steps, and the major scale

Discover the patterns behind every scale in western music. Learn why the major scale sounds the way it does, how key signatures work, and how to build any major scale from any starting note.

Beginner · 5 lessons · approximately 63 minutes of material (not a mastery deadline).

## Free lesson sample: Build G major from its step pattern

A major scale follows whole–whole–half–whole–whole–whole–half steps. A whole step is two semitones; a half step is one. The pattern, rather than a memorised finger shape, explains which notes need sharps or flats.

Before you start: Write the letters G–A–B–C–D–E–F–G. Use each letter once before returning to G. On a keyboard, neighbouring keys, including black keys, are a semitone apart.

### The example, written out
- Required gaps: W–W–H–W–W–W–H.
- Candidate notes: G–A–B–C–D–E–F–G. Which note needs changing?

### Try it step by step
1. Check G–A, A–B, and B–C. They already give whole, whole, half.
2. Continue through C–D and D–E. Compare the last two gaps, E–F and F–G, with the required pattern.
3. Change one pitch, then write the complete scale upward and downward. Identify the key signature that keeps the correction in effect.

### Worked answer
Raise F to F sharp: G–A–B–C–D–E–F♯–G. E–F♯ becomes a whole step and F♯–G a half step. G major therefore has one sharp, F♯, in its key signature. Descending G major uses the same notes in reverse; it does not remove the sharp.

### Common mistakes
- Do not write G♭ instead of F♯ in this scale: although they can share a keyboard key, a correctly spelled scale needs one of each letter.
- The B–C and F♯–G half steps are intentional; a major scale is not made only of whole steps.

[Learn to name the distances between scale notes](/learn/theory/intervals)
[Compare the major pattern with minor scales](/learn/theory/minor-scales)

## Before this module
- [Foundations of Music](/learn/theory/foundations), The alphabet, the staff, and reading notes

## What this module covers
1. **Half Steps & Whole Steps**, The smallest distances in Western music (8 min)
2. **The Major Scale**, The pattern of whole and half steps behind Western music (15 min)
3. **Key Signatures**, The sharps and flats that define a key (14 min)
4. **The Minor Scale**, The darker, more complex sibling of the major scale (14 min)
5. **The Circle of Fifths**, The map of all keys and their relationships (12 min)

## Practise with a free reference
- [Public scale references](/learn/scales), Read pitch sequences and play reference examples. Available routines do not establish an exam syllabus requirement.

## What comes next
- [Intervals](/learn/theory/intervals), The distance between any two notes

## Where should I start with scales & keys?
The curriculum places Foundations of Music before this module. Review those topics if they are unfamiliar. The first lesson is “Half Steps & Whole Steps”: The smallest distances in Western music. The order is a study guide, not proof that every learner needs the same pace.

## How long is the scales & keys module?
The 5 listed lessons total approximately 63 minutes of material. That estimate describes lesson content, not the practice time needed to become comfortable with half steps, whole steps, and the major scale. Revisit one task at a time and use feedback from a teacher where physical technique is involved.

## What can I try here without an account?
The complete “Build G major from its step pattern” exercise, its worked answer and common mistakes are free on this page. The lesson list and linked public tools are also open. A free account includes the complete five-lesson foundation module in each instrument and five lessons in music theory, with saved progress and no expiry. Later lessons require the relevant paid package.

## Continue in Arco
The complete five-lesson foundation module in each instrument and five music theory lessons are free with an account, including saved progress and no time limit. Later lessons require the relevant paid package. Public samples do not assess your physical technique or certify exam readiness.

[See packages and pricing](/pricing) · [Back to the music theory curriculum](/learn/theory)

Canonical source: https://arcosounds.com/learn/theory/scales-keys