Scaling Tk scrollbar handles

[Gordon Airport]

None of the online references that I'm using or can find tell you if 
this can be done. It's standard practice in GUI's to have the handle of 
a scrollbar sized to be the proportion of total ammount of viewable data 
to the ammount you can see in the current view region. (I think that 
explains it, you know what I mean.) I have a scrollbar attached to a 
canvas, and it scrolls properly, but it always has a tiny little handle. 
Is there anything I can do about this?