Musical instruments capable of producing different pitches -- such as the human voice, piano, flute, viola or trombone -- can play patterns of pitches that either ascend or descend. Ascending pitch patterns will move into a higher register, or towards the player's right when sitting at a piano keyboard; descending patterns will move to a lower, thicker or longer string on a stringed instrument or to the left of a keyboard. Several musical terms are applied to various ascending and descending musical pitch patterns.
Musical scales are patterns of whole and half steps which are played sequentially and can be either ascending or descending. For example, the C major scale runs through the ascending pitches C-D-E-F-G-A-B-C or the descending pitches C-B-A-G-F-E-D-C; on a piano, the C major scale uses all the white keys; you can play ascending and descending scales starting on any pitch. Major scales and harmonic minor scales use the same pitches in ascending and descending forms, while melodic minor scales differ slightly between ascending and descending versions. For example, the A melodic minor ascends A-B-C-D-E-F#-G#-A and descends A-G-F-E-D-C-B-A.
Arpeggios are ascending or descending patterns of leaps that outline the notes of a chord; this can be a major, minor, seventh or any other chord. For example, an ascending C major arpeggio over two octaves would use the pitch sequence C-E-G-C-E-G-C; the same arpeggio would descend using the pitches C-G-E-C-G-E-C.
Other Modes and Scales
Musical modes are other scale patterns which may ascend and descend in stepwise -- like a scale -- or arpeggiated form. The Aeolian mode, for example, runs from A to A on the white notes of the piano, ascending A-B-C-D-E-F-G-A, while the pentatonic scale uses five notes per octave, for example G-A-B-D-E-G. The black notes on a piano keyboard also form a pentatonic scale.
A glissando is an ascending or descending "sliding" musical figure in which all the notes between one pitch and another are played quickly. On a xylophone, for example, a musician can create a glissando by playing all the notes on the lower manual -- the "naturals" which would be white notes on a piano -- in a swooping motion up or down the keyboard. On a trombone, a smooth glissando effect is produced by lengthening or shortening the trombone slide position.