A violin bow is a tool used to produce sound on a violin. It consists of a long, slender stick made of wood or synthetic materials, with horsehair stretched between its ends. The player draws the bow across the strings of the violin, causing them to vibrate and create music. The tension of the horsehair can be adjusted using a screw mechanism at the frog, which is the part of the bow held by the player. Proper technique and bowing styles are essential for achieving different tones and dynamics in violin performance.