Scales and Octaves

What is a Scale?

A scale is a series of notes in ascending (going up) or descending (going down) order. In many scales, there are eight notes. Most scales, such as the D major scale below, begin and end on different octaves of the same note (in the below case, the scale begins and ends with "D").

What is a step? The distance between two notes next to each other is called a step. In a major scale, such as the D major scale, all the steps are "whole" steps, except the steps between the 3rd and 4rth notes, and the 7th and 8th notes. This order of whole steps and half steps is the same for all major scales.A half step is the smallest interval, or space, between two notes. A whole step is an interval that is composed of two half steps. For instance, in the scale below, between the "B" and "C#" of the scale is C natural, which is a half step below C# and half step above B.

Scales composed completely of half steps are called chromatic scales. Below is a chromatic scale starting on D. Notice that there are more notes (12) in this scale. Now it is easy to see notes included here that were not part of the D Major scale.

What is an Octave?

In the example above, the sound of the lowest D (the first note in the image) is made by sound waves that are exactly twice as slow as the the "D" one octave above (the next "D"). Likewise, the highest D is made of sound waves that are twice again as fast. For example, if the frequency of the sound waves of the lowest D is around 300, the second D has a frequency of 600, and the highest D has a frequency of 1200.