A squash ball is made from two pieces of rubber material that are glued together to form a hollow inside. When first used they have very little bounce.
(Photo Credit: funkypancake)
In order for them to be bouncy enough for a game they have to be warmed up. This is usually done with a few practice hits on court or by rubbing the ball against the floor using your shoe, doing so warms the air inside the ball, which then expands and makes the ball more bouncy.
Slow or Fast Ball
Interestingly the better you are at squash the slower the ball you should use. The slowest ball used by most good club level and above players has two yellow dots printed on the side of it. The next slowest ball has just one yellow dot on its side.
Beginners should start with the faster balls that are quite bouncy. The fastest ball is blue in color, is 12% larger than other balls and has a high bounce.
Improvers can use a ball that is 6 per cent larger than a standard ball and black in color.