[animations of a clef with notes and accidentals, narrator speaking:]This symbol when placed next to the note on the line, representing a particular pitch, like this, tells us to play that pitch sharp for the rest of the measure. For example, this note tells you to play the pitch "G". If the symbol for a sharp note is added, we are simply instructed to play the "G" sharp every time it occurs in that measure. When this symbol is added to the note, we are instructed to play the pitch flat. This is "G" again, and this is "G" flat. This symbol is called a natural. It is used to restore the line of space to its natural pitch from a sharp or flat pitch.