Seconds and Thirds

Introduction

Since scales are made up of seconds and chords are made up of thirds, we have to learn about these musical intervals in order to understand scales and chords.

Intervals

The distance between two musical pitches in called an interval.

Defining Intervals

Intervals are classified by name and mode.

Interval Names

The name of the interval is based upon the distance between the letter names of the two pitches in the interval. So, the interval C,D is a second, because if you consider C to be the first note in the interval, the next letter name (D) is the second note in the series of pitches, so the interval is called a second. C,E is a third, because if you consider C to be the first note in the interval, the next letter name (D) is the second note in the series of pitches, and the next letter name (E) is the third in the series of pitches, so the interval is called a third.

Interval Modes

The mode of the interval is based upon the distance and nature of the interval. In our case, we want to determine whether the interval is major or minor. Here are the guidelines:
Determining the mode of a second
Determining the mode of a third

Performing the Intervals

Example 1: piano keyboard:



Playing a minor second
To play a minor second, starting on C, you would play "C,D flat", so you would press down the number 1 and number 2 keys in the example above, since key number 1 is "C", and key number 2 is "D flat".
Playing a major second
To play a major second, starting on D, you would play "D,E", so you would press down the number 3 and number 5 keys in the example above, since key number 3 is "D", and key number 5 is "E".
Playing a minor third
To play a minor third, starting on F, you would play "F,A flat", so you would press down the number 6 and number 9 keys in the example above, since key number 6 is "F", and key number 9 is "A flat".
Playing a major third
To play a major third, starting on E flat, you would play "E flat,G", so you would press down the number 4 and number 8 keys in the example above, since key number 4 is "E flat", and key number 8 is "G".
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