String instruments make sound through vibrating strings, set in motion by bowing or plucking and resonated by a body or, in some designs, amplified electronically. This collection spans several distinct forms: the violin is a bowed instrument with a bright, expressive range, while the zither has strings stretched over a soundboard and is played by plucking. The banjo's taut membrane head gives it a distinctive resonant tone; the balalaika is recognizable by its triangular body; and the bass guitar provides low notes in many ensembles. Together, these examples show how string instruments vary in shape, playing technique, and musical role while sharing the same basic sound-producing principle.