What are accidentals in music?

Accidentals in music refer specifically to sharps, flats, or naturals that are placed before notes to alter their pitch from the standard notes in the scale. When an accidental is used, it changes the note it precedes by raising or lowering its pitch, allowing for more expressive possibilities and the creation of various musical effects. These changes can apply to a single note, affecting how it is played within a piece of music, often creating tension or resolving melodically.

In this context, the other options do not accurately describe accidentals. Notes that are never used don't fit into the definition of accidentals since they have no musical application. Notes played with vibrato refer to a technique used to add richness and warmth to a note, but they do not pertain to accidentals. Rhythmic patterns relate to the timing and duration of notes rather than their pitch alterations. Hence, the correct understanding centers around how accidentals function to modify notes within music.