What is the purpose of the pedals on a grand piano and how do they affect the sound produced by the instrument?

The pedals on a grand piano serve to alter the sound produced by the instrument. The purpose of the pedals is to sustain, soften, or change the tone of the notes played. The sustain pedal allows the notes to ring out longer, the soft pedal reduces the volume and changes the tone, and the una corda pedal shifts the hammers to strike fewer strings, creating a softer sound.