Seeing Intervals

Purpose: Learn to recognize and understand the names of the intervals that make up melody and harmony: the seconds, thirds, fourths, etc. and their various qualities of major, minor, augmented, and diminished. This exercise also helps you to understand the difference between intervals that sound the same on the piano but are written differently on the staff: for instance, the minor third and the augmented second.

Difficulty: Beginning level for the diatonic intervals without key signatures, moderately difficult for those in the context of key signatures. You'll begin with the smaller intervals and more will be added as you progress - including the augmented 4th and diminished fifth that are natural to the current key. Level 3 intervals will all be augmented or diminished and will usually involve a flat or sharp on one of the notes.

How it works:

Touch the box that corresponds to the correct name of the displayed interval. You can play the keyboard if you like, but it will not enter notes on the staff in this exercise. If you make a mistake you'll be shown the right answer.

You can use any clef for the displayed music. To choose a new clef just click on the clef tool above the keyboard and touch the one you want. You can also specify a key signature, but only when you're in Practice mode.

To enter Practice Mode touch "Practice" at the top of the screen. In Practice mode you'll be able to choose the intervals you want to learn. To bring up the practice window again touch "Change practice choices" above the selection boxes. To leave practice mode touch "Exit Practice" at the top of the screen.

How intervals are named

For help with naming intervals you can download our free eBook, Exploring Theory with Practica Musica from the iBook store. Intervals are presented in Chapter V with the help of multimedia examples.

Intervals are named according to their number and their quality. That is, the number of letter names included between the two notes and the size of the interval in half steps.

Because letter names correspond to the lines and spaces in staff notation, another way to describe an interval is by the number of lines and spaces it covers. The third E-G in the treble clef starts on a space and goes to the next space. That's three things: space, line, space, also three letter names: E, F. G. So it's a third.

But what is the quality of that third? For that you count the half steps from E to G: there are 4, making it a major third.

Seconds, thirds, sixths, and sevenths have two basic qualities: major and minor. The minor version of each is a half step smaller than the major. A third with 4 half steps is a major third, one with 3 is a minor third.

Unisons, fourths, fifths, and octaves have only one basic quality, which is perfect. A fourth with 5 half steps is a perfect fourth. Reduce a perfect interval by half a step and it becomes diminished, enlarge it by a half step and it's augmented.

Seconds, thirds, sixths, and sevenths can also be diminished or augmented. One half step smaller from minor is diminished, one half step larger from major is augmented.

What the thing that confuses people the most? It's the fact that two intervals can have the same number of half steps and are played on exactly the same piano keys but have different names depending on how they are written.

Just remember that interval names are based on their notation, not on how they sound.

It might seem silly now, but later on in your music study you'll see why a "major third" is not treated the same in composition as an "augmented second," even though they sound the same on a keyboard.

To identify an interval: get its number from the number of letter names or lines and spaces that it includes. Then count the half steps to get its quality. At first you may want to refer to a table like the one above, but before long the common intervals will be second nature to you. For tips about how to quickly identify intervals check Chapter V of Exploring Theory.

Finally: Why do you want to know this? That is, aside from it maybe being a school assignment. For one thing, understanding the naming of intervals is essential to building chords and particularly essential for understanding part-writing - making several voices combine in a meaningful way. And then there's just the pleasure of knowing how things work.

Here are the most common intervals as they would appear starting from F, and with their sizes in halfsteps.

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