What are the possible reasons of violin bow jumping?

– Uneven pressure and tension. Correct your bow grip to reduce excessive pressure, which can be one of the primary offenders for a bouncing bow. Keep your grip soft (but also not too loose), and your thumb relaxed. Additionally, avoid tensing up when you're playing, especially in your wrist and shoulder.

1. Why does my bow jump?
2. What is it called when you bounce the bow on the violin?

Why does my bow jump?

There are 2 common causes for bouncing bow. Often there is a combination of the 2 at play. Your bow is too tight. You have tension in your bow arm.

What is it called when you bounce the bow on the violin?

Spiccato [spikˈkaːto] is a bowing technique for string instruments in which the bow appears to bounce lightly upon the string. The term comes from the past participle of the Italian verb spiccare, meaning "to separate". The terms martelé, saltando, and sautillé describe similar techniques.