Football is an oval-shaped ball made of leather or rubber， usually inflated with air. The ball has an oblong shape with pointed ends. It is typically around 22 cm (8.7 in) in diameter and 68-70 cm (27-28 in) in circumference. The surface of the ball is usually covered in a pattern of black pentagons and white hexagons to make it easier to grip and throw. The ball’s weight is often regulated and should not be more than 450 g (16 oz).
The inside of a football is usually made of two layers of rubber， which are connected together by bonding glue. A bladder is placed in between these two layers and is filled with air. The bladder is usually made of latex， rubber， or butyl. This is what gives the ball its shape and allows it to keep its bounce. The bladder also helps keep the air pressure of the ball regulated.
The exterior of the ball can be made from a variety of materials. Leather is the most common， but synthetic materials are becoming increasingly popular. These materials are designed to be more durable and provide better control when kicking or passing the ball.
In general， a football is an oval-shaped ball made of leather or rubber， with a bladder inside to keep it inflated. It is typically around 22 cm (8.7 in) in diameter and 68-70 cm (27-28 in) in circumference and usually weighs around 450 g (16 oz). The exterior of the ball is usually covered in a pattern of black pentagons and white hexagons to make it easier to grip and throw.
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