In music theory, how is a perfect interval altered to become augmented?

A perfect interval is altered to become augmented by raising it by a half step. In music theory, intervals are classified as perfect, major, minor, augmented, or diminished based on the number of half steps they contain. A perfect interval includes intervals such as perfect fourths, fifths, and octaves.

When a perfect interval is raised by a half step, it adds an additional half step to the original measurement of the interval, transforming it into an augmented interval. For example, if you take a perfect fifth, which consists of seven half steps, raising it by a half step increases the total to eight half steps, thus transforming it into an augmented fifth.

This alteration fundamentally changes the quality and sound of the interval, leading to different harmonic and melodic possibilities in musical compositions. Understanding this relationship between perfect and augmented intervals is essential for musicians as it affects voice leading, harmony, and the overall structure of musical works.