Football is a team sport in which players attempt to move the ball into the opposing team’s end zone by running with it until tackled or by passing it to another player downfield. Each team has 11 players on the field at one time. Teams are allowed unlimited substitutions during play, but any player leaving the field must be replaced by an eligible substitute before the next play begins.
Despite its rough nature, the game is structured with a clear set of rules that help to keep it fair for both teams. Referees monitor the play, blow their whistles when players are tackled or touched, and throw flags when there is a penalty. Penalties typically result in the offending team losing 5-15 yards of field position.
The object of the game is to score more points than the opposing team within a limited time of four quarters. Points are scored by kicking field goals (3 points), touchdowns (6 points), two-point conversion (2 points) and safety (2 points). A team can also earn bonus points for scoring a touchdown or a two-point conversion in its own end zone.
A football is a large rubber or leather ball that is slightly larger than a baseball. The balls are carried by hand or by a shoulder strap attached to the quarterback or other designated player. The game originated in England and was modified by a meeting of representatives of various clubs and associations in London in 1848, which determined that carrying the ball with the hands wasn’t permitted. By 1912, the game had achieved its modern form, with a standardization of field size and rules and a growing national following.
The game is played on a grass field with numbered yardage markers. The end zone is marked by a line on the field, and there are numbers that descend every ten yards (40, 30, 20, 10, etc.) until they reach the 50-yard line, which is in the center of the field. The goal line is also indicated by a line on the field.
Once a team has possession of the ball, it must advance it at least 10 yards downfield before being forced to punt the ball back to the other team. The first team to do so wins the game. Alternatively, the offensive team can try to score a touchdown within three downs, or the defensive team can force the offensive team into their own end zone by either tackling them in their own end zone, having their flag pulled by a defender, or by a fumble.
Each team has offense players, defense players and a group of specialized players called “special teams.” Special teams handle kicking and kickoffs. The special teams also handle punts, field goals and extra points. A kicker is the most important member of the special teams. He must be able to kick the ball straight, long and high. He must also be able to jump, run fast and make good decisions.