Learning Objectives
- Indicate the numerical size of an interval by counting the notes between two pitches.
- Identify whether an interval is ascending or descending.
- Using the piano keyboard, indicate the numerical size of a given interval.
- Explain the interval of an octave and identify it on the staff and keyboard.
Intervals
The distance between two pitches is called an interval. As you know by now, pitches may be indicated by the position of a note on the staff or by a letter name (for example, A, G, or D). Another way of putting it is that an interval is the distance between two letter names.
To find out the interval between two notes, count the number of letter names between the two of them. Make sure to include both the starting and ending notes in your count. For example, the interval from any note to its nearest neighbor is two; we call that a second. For example, the interval between the notes C and D is a second. The interval between D and A would be a fifth. Why? Well, if you count D as note number 1, E would be 2, F would be 3, G would be 4, and finally, A would be 5.
Intervals may be ascending (as in the previous examples) or descending. Descending intervals are calculated exactly the same way as ascending ones. For example, the descending interval between A and F is a third: Count A as note 1, G is note 2. Next comes F, our destination, which is note 3.
Use the keyboard to play intervals
As an exercise, find out what the ascending interval is between D and G.
If your answer is a fourth, you are right. And the explanation is simple: starting with D as note 1, count consecutive letter names until you reach G (and remember to include G in your count).
A very important interval is the one that happens between a note and its next occurrence (the same letter name) up or down the keyboard. That interval is called an octave. The two notes of an octave look alike on the keyboard and sound quite similar due to the simple relationship of their frequencies: the higher tone vibrates at twice the frequency rate of the lower tone.