Why do violins need rosin on the bow?

Answer: Creates friction to vibrate strings

Creates friction to vibrate strings ✓ — Correct! Rosin is sticky tree resin that creates friction when bow hair rubs across strings. Without rosin, the bow would slide smoothly without making strings vibrate. The friction from rosin causes strings to stick and slip rapidly, creating the vibrations that produce sound.

Protects strings from damage — Wrong. Rosin is for the bow, not string protection. It helps the bow grip strings to make them vibrate and produce sound.

Makes bow slide more smoothly — Wrong. Rosin does the opposite—it makes the bow sticky, creating the friction needed to vibrate strings and produce sound.