Most bow sounds that emerge from young learners are less than brilliant, and that's because there is so much to think about and its pretty darn difficult...
The majority of problems come when the bow moves too slowly producing a scratchy sound. I explain to my students that it's like a car with the breaks on, if it's not continuously moving, the car will produce a screechy sound. The bow is like a moving car, it has to keep moving at a continuous pace. The faster the bow, the more brilliant the sound, as long as (and this is important) there is not too much bow pressure! crushing the bow into the string is the other mistake kids can easily make. The string needs to vibrate in order to produce a brilliant sound. If you press to hard the string can't produce a ringing sound. Particularly with chords, a lot of bow is needed, and a fast arm - almost like they are pushing someone away. If the sound is on the other hand too quiet, then they are also not moving the bow fast enough. Lastly, check the bow grip is firm, and the arm is at the right string level. A lazy bow grip means the bows contact with the string will be not as effective, and it won't matter how fast the arm is moved!
Sounds like a weird blog title I know! But today I noticed something in a student that affects some of my students more than others. If I have an enthusiastic student, they are often so eager to play something that instead of analyzing a phrase in their head first, they rush/stumble forward - repeating certain notes over and over and not progressing with their rhythm or intonation in a very efficient way. When I say "practicing in their head", I want my students to approach a piece how they might when they were learning to read a book - to look at the shape of the word first, and imagine how it might sound before saying it. This would mean that they look at an entire bar or group of notes before playing it. To look for the fast and slow notes in the rhythm and sing it to themselves in their head first if necessary. Then they can look at the position their fingers will have to take over the entire bar and prepare their hands on the violin before they play the bar instead of working it out in the middle of the bar. Key words are - Stop, Look, Prepare!!
A way you could make this into a game would be to say that once they have started the bar they are not allowed to stop for the entire bar. This forces them to think ahead - they can compare how it sounded in their mind first with how it sounded after they played it, getting them into the habit of practicing longer sections at one time.
There is a new app called Cadenza which is downloadable through Itunes, I'm not sure if its available on android also. This is a new brilliant concept which allows the student to play through some popular classical repertoire with an accompaniment. I tried it out myself. I think it's still in the development stage however as if the student is not yet comfortable with the piece - for instance if they stop playing - the accompaniment stops also and gets confused. The difference they were trying to get with this application compared with playing along to a CD, was that the accompaniment actually follows your tempo slightly like a real accompanist would. This is not perfected yet though, and I was a little frustrated with the responsiveness. Also, it wasn't loud enough without an additional speaker that needed to be attached to the phone. The idea however is good, and its a fun app to have a play with. I would still recommend playing along to a recording until its developed further in the meantime.
Here I write my musings on teaching, or other things that come up in lessons/relate to violin learning. Anything suggested is just that, suggestions and my thoughts and may differ from the opinions of my other music colleagues!