soccer

Game play in American football consists of a series of downs, individual plays of short duration, outside of which the ball is dead or not in play. These can be plays from scrimmage—passes, runs, punts, or field goal attempts—or free kicks such as kickoffs. Substitutions can be made between downs, which allows for a great deal of specialization as coaches choose the players best suited for each particular situation. During a play, each team should have no more than 11 players on the field, and each of them has specific tasks assigned for that specific play.

The object of the game is to score points by advancing the ball to the opponent's end zone for a touchdown, which is worth six points. A team may also score by kicking the ball through goal posts in the back of each end zone for a field goal, which is worth three points. It is also possible for a team to score points by tackling the other team's ball carrier in their own end zone, called a safety, which is worth two points. Additionally, after scoring a touchdown, a team may attempt a close-range field goal kick to add an extra point, bringing the total points to seven, or the team may attempt to advance into the end zone to add two extra points, called a two-point conversion, bringing the total points to eight. The team with the most points when time has expired wins.
Collegiate and professional football games are 60 minutes long, divided into four quarters of 15 minutes each. In high school football, 12 minute quarters are usually played.