Which scale is known for raising the seventh note when ascending?

The scale that is characterized by raising the seventh note when ascending is the harmonic minor scale. This scale is built upon the natural minor scale, but it features a distinctive alteration: the seventh degree is raised by a half step. This alteration creates a leading tone that provides a stronger resolution to the tonic chord, which is particularly useful in harmony and melodic development within both classical and contemporary music.

In contrast, the natural minor scale maintains the seventh note in its original state, which does not facilitate the same sense of tension and resolution found in the harmonic minor. On ascending, the melodic minor scale raises both the sixth and seventh degrees, but this change only applies when moving upwards; when descending, it reverts to the natural minor scale, which does not apply to the question. The major scale, while also commonly used, does not involve the lowering of the seventh degree either; it naturally has a raised seventh degree but is structured differently. Therefore, the harmonic minor scale's specific alteration of raising the seventh note when ascending makes it the correct choice.