Musical modes are specific scales that create different moods and feelings in music. They are derived from the major scale and consist of seven notes, each starting from a different note of the scale. The most common modes include Ionian, Dorian, Phrygian, Lydian, Mixolydian, Aeolian, and Locrian. Each mode has a unique pattern of whole and half steps, which gives it a distinct sound. For example, the Ionian mode is the same as the major scale, while the Aeolian mode corresponds to the natural minor scale. Musicians use these modes to add variety and expressiveness to their compositions, allowing for a wide range of emotional expression.