Soccer

Official World Cup 1986 Azteca Soccer Ball

Azteca: México, 1986 The FIFA World Cup Mexico, saw the introduction of the first polyurethane coated ball which was rain-resistant. The first synthetic match ball, with good qualities on hard and wet surfaces.   The above picture was provided by Sebastiano Calì from Italy. Thanks! The above “red letter” ball picture was provided by Jacques Barralon The above “black …

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Official World Cup 1982 Tango Espana Soccer Ball

Adidas introduced a new ball which had rubber inlaid over the seams to prevent water from seeping through. The first ball with water-resistant qualities. General wear from kicking however meant the rubber began to wear after a short time and needed to be replaced during the game. The last genuine leather world cup ball.   The above picture was …

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Official World Cup Tango 1978 Soccer Ball

Soccer ball design experienced another revolution in 1978 with the introduction of the Adidas Tango. Adidas had created what would become a ‘football design classic’. Twenty panels with ‘triads’ created the impression of 12 identical circles. For the following five FIFA World Cup tournaments, the Match Ball design was based on this design. Tango featured …

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Drag vs Speed

The variation of drag force with ball speed. At high speeds, the drag force falls, which means that the ball does not slow down as much as expected. First published in Physics World magazine, June 1998 pp25–27.  https://physicsworld.com/a/the-physics-of-football/

Soccer Turbulent Air & Drag

When the airflow over a ball is turbulent, the boundary layer sticks to the ball almost until the air has completely passed over the ball. This produces late separation and a small drag. First published in Physics World magazine, June 1998 pp25–27.  https://physicsworld.com/a/the-physics-of-football/

Ball Drag

The drag coefficient of a ball plotted against Reynold’s number – a non-dimensional parameter that takes into account both the velocity and diameter of the ball. The drag coefficient drops suddenly when the airflow at the surface of the sphere changes from laminar to turbulent. The position of the discontinuity depends on the roughness of …

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Spinning Ball

A bird’s-eye view of a football spinning about an axis perpendicular to the flow of air across it. The air travels faster relative to the center of the ball where the periphery of the ball is moving in the same direction as the airflow (left). This reduces the pressure, according to Bernoulli’s principle. The pressure …

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