The blue ball in the game of pool is the #2.
The number 2 ball is a solid blue color.
Zero. There are no points in conventional pool games for any balls, although in straight pool, a point is scored for each legally pocketed ball, regardless of color.
5
A six ball for pool is dark green.
15
8
All pool games require that certain balls be identified. If you chose to use a custom set of pool balls with only the markings necessary for a particular game, it would not be contrary to the regulations to do so.
White - cue ball Yellow - 1 and 9 Blue - 2 and 10 Red - 3 and 11 Purple - 4 and 12 (except for televised games when pink is used in the US) Orange - 5 and 13 Green - 6 and 14 Brown - 7 and 15 Black - 8 ball
Blue
5.96 cubic inches. This volume is for a US regulation pool ball which is 2.25 inches in diameter. As a pool ball is used, its size slowly decreases and it becomes out of round. This is due to the abrasive pool chalk used in the game, which is more like sandpaper than like chalk. So, this number applies only to a new pool ball.
nothing
8 ball pool, 9 ball pool, billiards.