Why do violins have white flakey stuff?

The white flakey stuff on violins is called "rosin". Rosin is a type of resin that is applied to the bow of a violin in order to create friction between the bow and the strings. This friction is necessary in order to produce sound when playing the violin. Rosin is typically made from pine resin, although other types of resins can also be used. It is usually applied to the bow by rubbing the bow against a block of rosin.

Rosin can appear to be white and flakey because it is a solid material that is made up of tiny particles. When these particles are rubbed against the strings of a violin, they break off and create the white flakes that are often seen on violins. Rosin can also be sticky, which is why it is important to clean the violin and bow regularly to remove any excess rosin.

Rosin is an important part of playing the violin, and it is necessary in order to produce sound. Without rosin, the bow would not be able to create enough friction against the strings to produce sound.