Title and topic description says it all!

They stop the Bridge from Vibrating so it sounds abit Muffled.
In other Words Muted

Dstring

Aah
Thanks!

They come in different sizes and weights which give a different effect. Some are known as orchestral mutes, because they sit on the strings by the tailpiece, ready to be clipped on to the bridge in an instant. These are made of wire and plastic, or rubber. Traditional ones are shaped like a three-pronged fork without a handle, made of wood and sometimes metal - there are very heavy versions which kill the sound completely for practising scales at 3am!

To get an idea of the effect try squidging a lump of blutack on to the bridge.

I don't like the Bluetack bit though

Thanks
Though I'm not quite brave enough to put blutack on my bridge - if i so much as go near my bridge it'll collapse. (clumsy me)

Blutack works all right in an emergency and doesn't do any harm. Take a round blob the size of a large pea and press it gently on the bridge between the middle strings, so that bridge cuts into it and the blob sits secure without touching the strings. Different sizes of blobs will give different effects.

If your bridge is really so precarious you should take it to a repairer to have it straightened. Or maybe your teacher would do it. Otherwise it might suddenly fall down or worse still snap - this happened to a friend in our last concert so that he had to sit through an entire Tchaik symphony, unable to play

......providing you remove ALL traces of it from the bridge immediately after use. Don't leave it. The wood of the bridge may feel smooth, but the grainy surface will trap a small amount of residue of whatever it is you stuck to it.

Personally, I wouldn't recommend sticking anything to the bridge.

My stand partner in the school orchestra had his tail gut snap during 'When A Child Is Born'. The talpiece and all four strings went flying and took a chunk out of his chin.
Can't hear that song now without whincing.

Yes, there's a fair amount of tension in the strings of a violin, something like 20 kilograms. If the tailgut snaps, it goes with a bang.

Perhaps this highlights that it's worth inspecting the instrument carefully once a week, just to see what wear and tear is going on.

I used to put a clothes peg or two on my bridge to mute the sound slightly. I found this worked better than a mute that I bought. As it was only for practicing it didn't bother me but I can imagine people would laugh outside.

Just out of interest why do some orchestral string players use mutes? The violin isn't exactly the loudest instrument hence the large number of them in an orchestra

Some music has directions to play with a mute 'Con sordini' the type of mute used is to shape the sound, giving it a softer, nasal quality rather than to make the instrument quieter as a practice mute does.

Also there aren't just a lot of violins in an orchestra because the violin isn't a loud instrument.
A good violin can be LOUD! A single fine violin can fill a concert hall such that it is hard to believe it isn't amplified.

Is there a very big difference in terms of loudness between a rubber and a metal mute? I've actually been recommended to get a metal mute because I sometimes get a crazy urge to play in the middle of the night but I can't because the house I'm living in now has pretty thin walls and my aunt and uncle are asleep by 9pm so it's not really nice to disturb them. I still think my rubber mute doesn't really dampen the sound sometimes. Sophia can still be loud!

The rubber Ultra practice mute works pretty well, I couldn't imagine anyone thinking the violin was still too loud with one of those.
The Prefessional and Tonwolf metal practice mutes are supposed to be quieter (never tried one) but I am wary of clipping anything as hard and unyeilding as a lump of metal onto my bridge and cringe at the though of one accidentally falling onto the belly of the instrument.

If you want quiter practice you could also try laying a folded handkie on the violins belly over the f holes.
Keeps rosin off the instrument too.