When a song consists of notes from a particular scale, it is said to be written in the key which has the same notes as that scale. For example, if a song contains mostly notes from the C major scale, it is said to be in the key of C major.
The following song Arkansas Traveller is in the key of C major. Notice that the melody goes to a D note at the same time as the D minor chord occurs, using the principle demonstrated in the previous example. Notice also the use of sequences in this melody.
Rhythm Pattern