What does a capo do on a guitar and how does it affect the sound and playability of the instrument?

A capo is a device used on a guitar to change the pitch of the strings without adjusting the tuning. It is placed on a specific fret of the guitar neck, effectively shortening the length of the strings and raising the pitch. This allows Guitarists to play in different keys and create a brighter, higher-pitched sound. The capo can also make certain chords easier to play and can enhance the playability of the instrument by expanding the range of available notes.