Australian rules football is being played with an oval ball that weighs between 450 and 480 grams. Australian football is one of the few field sports that does not use uniform sized ground, it is an oval shaped just like the ball, that can vary in width between 110 and 155 meters and in length between 135 and 185 meters.
Two goal posts not less than 6 meters in height are placed 6.4 meters apart at each end of the ground. Two shorter posts called behind posts, rise to a minimum height of 3 meters, with one placed at the side of a goalpost at a distance of 6.4 meters. The line between the goal posts is called the goal line, and the lines extension from each goal post to its behind post is called the behind line.
A goal is scored when the ball is kicked through the goal posts by a member of the attacking team; a goal registers 6 points. A behind is scored when the ball crosses a behind line in any event or when the ball crosses the goal line without meeting all the required conditions for a goal to be scored (ex: when the ball touches a goalpost).