A violin bow is like a special stick that helps us play the violin. Imagine a thin stick that's about as long as your arm. On this stick, there are some very thin hairs stretched all the way from one end to the other. These hairs are usually made from horse hair, and they are very important because they help create sound!
When you take the bow and run it across the strings of the violin, the hairs rub against the strings. This rubbing makes the strings vibrate, and that's how we hear music! So, you can think of the bow as a bridge that connects our hands to the violin to let us make beautiful sounds.