Tones and Semitones – Whole and Half steps

In music theory, we need a way to measure the distance between two notes, much like a measuring tape. That unit of measurement is tones and semitones (whole and half steps). Understanding these “musical rulers” is essential for anyone on the road to improvisation or composition.

From the Archives: This lesson was a turning point in the “Theory Kitchen.” I always say that from the root, notes stem up like a plant: tones and semitones show how far apart the branches are. Once you know the building plan, or “recipe” for a scale, you can work out any scale in any key.

Lesson Chapters: The Measuring Tape of Music

This 12-minute lesson provides a mechanical system for calculating intervals. Use these timestamps to navigate:

• [00:03:06] – Defining the Semitone (Half Step): The smallest distance between any two keys on the piano (e.g., C to C#).
• [00:04:14] – Defining the Tone (Whole Step): Two semitones added together (e.g., C to D).
• [00:06:04] – Avoiding the “Zero” Trap: Why you don’t count your starting place when measuring.
• [00:06:42] – Challenging Intervals: Measuring the distance between B-flat and E (The “Tritone”).
• [00:09:51] – The Major Scale Building Plan: How tones and semitones create the specific sound of a major scale.

The Major Scale “Building Plan”

One of many applications of tones and semitones (whole and half steps) is constructing scales. Every major scale in existence follows this exact sequence of intervals:

Tone – Tone – Semitone – Tone – Tone – Tone – Semitone

In the “Theory Kitchen,” we call this the recipe. If you start on C and follow that pattern, you get the white keys. If you start on any other note, that same pattern will tell you exactly which sharps or flats you need to include.