what is the ball for on the side of glass pipes?

I would guess just for holding the pipe. I have troubles holding little ass pipes with my big ass hands but ones with balls are slightly easier.

 

It's just a for decoration, it's like a glass marble.

 

It's just a glass marble. I think mostly for looks, but maybe it helps you hold it a little bit. I also know that many glass makers put their initials in glass balls ahead of time, like many of them, at least a few dozen marbles probably. So that's how a lot of people put their initials in pipes.

 

If your asking if it actually has a function, it really doesn't. It's there for show/something to hold on to. Just adds to the design factor

 

It's for decoration, and can also come in handy if the bowl gets hot since the heat doesn't spread easily to those little bubbles.

 

they DO help absorb heat.... but a lot of the times the ones you see on pieces don't really do much, so it's a lot of times just a visual thing...

 

its all about the glass heating up not looks... no matter how hot the glass of the piece gets, the ball never heats up

 

On a chillum, though, the marbles prevent it from rolling