Soccer Law 2: The Ball

Dimensions

The ball used in football (soccer) is called a football or soccer ball. Law 2 of the game specifies the ball to be an air-filled sphere with a circumference of 68–70 cm (or 27–28 inches), a weight of 410–450 g (or 14–16 ounces), inflated to a pressure of 60–110 kPa (or 8.5–15.6 psi), and covered in leather or "other suitable" material. The weight specified for a ball is the dry weight: older balls often became significantly heavier in the course of a match played in wet weather. The standard ball is a Size 5. Smaller sizes exist; Size 3 is standard for team handball; others are used in underage games or as novelty items.

Construction

Most modern balls are stitched from 32 panels of waterproofed leather or plastic: 12 regular pentagons and 20 regular hexagons. The 32-panel configuration is similar to the polyhedron known as the truncated icosahedron, except that it is more spherical, because the faces bulge due to the pressure of the air inside. The first 32-panel ball was marketed by Select in the 1950s in Denmark. This configuration became common throughout Continental Europe in the 1960s, and was publicised worldwide by the Adidas Telstar, the official ball of the 1970 World Cup.

Older balls were usually stitched from 18 oblong non-waterproof leather panels, similar to the design of modern volleyballs and Gaelic footballs, and laced to allow access to the internal air bladder. This configuration is still common, as are more novel ones, such as the 26-panel Mitre PRO 100T, and the 2006 FIFA World Cup football, the 14-panel Adidas +Teamgeist (a truncated octahedron). There are also indoor footballs, which are made of one or two pieces of plastic. Often these have designs printed on them to resemble a stitched leather ball.

There are only 13 different possibilities for suitable spherical footballs. This includes the more notorious football of pentagons and hexagons that we use today. It is predicted that in 2010, a newly shaped football will be in use which will have 92 leather flaps the majority of which will be triangles and the rest will be squares and octagons.

Patterns

The archetype, black pentagon/white hexagon design was intended for maximum visibility on monochrome television sets. It is still used for generic balls and symbolic representations of the game. However, premium branded balls have other more elaborate patterns. The Nike Total 90 Aerow has rings intended to aid goalkeepers to determine the spin on the ball. "Official replicas" of the Teamgeist have its 14-panel pattern superimposed on a cheaper 28-panel ball. The official ball of the UEFA Champions League, the Adidas Finale has stars on the ball. Older balls were monochrome: originally brown; and later white, especially for floodlit matches. Brightly-coloured balls are used on snow-covered pitches.

Source: Wikipedia