The rules say that the soccer ball should 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), with an outside layer made of leather or another material, with the specific properties of leather. This 14 to 16 ounces weight is the weight that the ball should have in dry weather. The problem with older balls is that they always become much heavier if they get wet. The standard size of a ball is Size 5. But there are smaller sizes, like Size 4 and Size 3 (the latter being used for team handball); Size 4 and other sized balls are used in underage games or for personal entertainment.
The soccer balls that we see today are made from 32 panels of special leather or plastic. Those panels are waterproof, by default. A dozen panels are of pentagonal shape and the rest are hexagons. This built is similar to the polyhedron known as the truncated icosahedrons. However, it is “rounder”, because the faces expand and get tenser due to the air pressure.
The firm that marketed the firs soccer ball with a 32-panel built was Select. This happened in Denmark, in the 1950s. In only 10 years, this configuration became accepted for soccer balls in many countries in Europe. Then, in 1970, it was used by the Adidas Telstar to make the soccer balls for the 1970 World Cup. The older configuration for soccer balls meant using 18 oblong non-waterproof leather panels to cover the rubber bladder inside. They looked more like the volleyballs we see today. Also, they resemble the ancient Gaelic footballs.
But we still see this configuration for newer soccer balls, like the 26-panel Mitre PRO 100T, and the 2006 FIFA World Cup football, the 14-panel Adidas +Teamgeist (a truncated octahedron). The simplest balls, however, are the indoor footballs, constructed from one or two pieces of plastic.
At a time when television sets were black and white, the manufacturers decided to make the black pentagon/white hexagon design, in order to increase visibility for the people watching the game in front of the TV. Nowadays the visibility of the soccer ball isn’t a problem anymore, but people have become affectionate to the old design, and they still use this design on some models. But now, we see more and 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. For the UEFA Champions League, they put the European stars on the official Adidas Finale soccer ball.