Association Football

Association Football (more commonly known as football or soccer as well as the world game) is a team sport played between two teams of eleven players with a spherical ball. It is played by 250 million players in over 200 countries and dependencies, making it the world's most popular sport. It is played on a rectangular field with a goal at each end and the objective is to score by getting the ball into the opposing goal.

The Goalkeepers are the only players allowed to touch the ball with their hands or arms while it is in player and only in their penalty area. Other players mainly use their feet to strike or pass the ball, but may also use their head or torso. The team that scores the most goals by the end of the match wins. If the score is level at the end of the game, either a draw is declared or the game goes into extra time or a penalty shootout depending on the format of the competition.

Players, Equipment and Officials
Each team consists of a maximum of eleven players excluding substitutes, one of whom must be the goalkeeper. Competition rules may state a minimum number of players required to constitute a team, which is usually seven. Goalkeepers are the only players allowed to play the ball with their hands or arms, provided they do so within the penalty area in front of their own goal. Though there are a variety of positions in which the outfield players are strategically placed by a coach, these positions are not defined or required by the Laws.

The basic equipment or kit players are required to wear includes a shirt, shorts, socks, footwear and adequate shin guards. An athletic supporter and protective cup is highly recommended for male players by medical experts and professionals. Headgear is not a required piece of basic equipment, but players today may choose to wear it to protect themselves from head injury. Players are forbidden to wear or use anything that is dangerous to themselves or others such as jewellery or watches. The goalkeeper must wear clothing that is easily distinguishable from that worn by other players and the match officials.

A number of players may be replaced by substitutes during the course of the game and the maximum number of substitutes permitted in most competitive international and domestic league games is three, though the permitted number may vary in other competitions or in friendly matches. Common reasons for a substitutions include injury, tiredness, ineffectiveness, a tactical switch or timewasting at the end of a finely poised game. In standard adult matches, a player who has been substituted may not take further part in the match. Any decision regarding points awarded for abandoned games is left to the individual football associations.

A game is officiated by a referee, whose decisions are final and have full authority to enforce the Laws of the Game in connection with the match to which he has been appointed. The referee is assisted by two assistant referees and in many high-level games there is also a fourth official who assists the referee and may replace another official should the need arise.

Ball
The ball is spherical with a circumference of between 68 and 70 centimetres (27 and 28 in), a weight in the range of 410 to 450 grams and a pressure of between 0.6 and 1.1 bars (8.5 and 15.6 psi) at sea level. In the past the ball was made up of leather panels sewn together, with a latex bladder of pressurisation, but modern balls at all levels of the game are now synthetic.

Ball in and out of Play

 * Kick-Off: Following a goal by the opposing team or to begin each period of play.
 * Thrown-In: When the ball has crossed the touchline, awarded to the opposing team to what which last touched the ball.
 * Goal Kick: When the ball has wholly crossed the goal line without a goal having been scored and having last been touched by a player of the attacking team, awarded to defending them.
 * Corner Kick: 
 * Indirect Free Kick:
 * Direct Free Kick:
 * Penalty Kick:
 * Dropped-Ball:

Governing Bodies
The recognised international governing body of football (and associated games such as beach soccer and fustal), is FIFA. The FIFA headquarters are located in Zurich, Switzerland, and six regional confederations are associated with FIFA, these are:
 * Asia: Asian Football Confederation (AFC)
 * Africa: Confederation of African Football (CAF)
 * Europe: Union of European Football Associations (UEFA)
 * North/Central America and Carribean: Confederation of North, Central American and Carribean Association Football (CONCACAF)
 * Oceania: Oceanian Football Confederation (OFC)
 * South America: Confederation Sudamericana de Futbol/Confederaco de Futebol (South American Football Confederation; CONMEBOL)