American football rules

American football grew out of the English game of rugby. Unlike soccer, the foot hardly ever touches the ball in American football. (Soccer is the game most of the world calls football.)

The Field is 100 yards long (and 160 feet wide). The middle of the field is the 50 yard line. The lines are labeled every 10 yards descending in both directions from the 50 yard line. Thus there are two 40 yard lines and no 60 yard line. Each team owns half of the field (they switch sides every 15 minutes of play). Thus, the two 40 yard lines are distinguished by who owns them. The "zero yard line" is called the goal line. The areas to either side of those 100 yards, extending 10 yards past the goal lines, are called the end zones. Teams try to get the ball past the opponent's goal line into the end zone to score a touchdown. At far edge of each end zone are the goal posts which, together with the cross bar, look like a big H. These are used only when a team decides to kick a field goal instead of going for a touchdown or to kick for an extra point after scoring a touchdown. To score the field goal or extra point, the ball must go between the vertical posts and over the bar.

In the other direction, the field is divided into three parts, left, center and right, by the hash marks, which are 60 feet from each side line. Normally, for each play, the ball starts where it ended up at the end of the previous play. However, if the ball ends up outside of the center part of the field, it is brought back to the nearest hash marks so plays never start at the extreme sides of the field. The area to either side of the field is out-of-bounds.

Kickoffs: At the start of the game there is a coin toss to see which team gets the ball first. The team that has the ball is the offense; the other team is the defense. A football game is supposedly one hour, but takes about three hours to play because the clock is often stopped for various reasons. The game is divided into 15 minute quarters with a major division at 30 minutes which is called half time. At the end of the first and third quarters, the players merely switch sides. The ball is moved to the corresponding point on the other side of the field, and play continues. This switching of sides evens up any advantage due to the sun or wind. The players leave the field for 20 minutes at half-time. After half-time, play does not continue where it ended. Instead, the team that originally lost the coin toss gets to have the ball first following another kickoff.

At the start of each half and after each touchdown or field goal (when it's time to let the other team have the ball), the defending team starts by placing the ball on a tee at their 35 yard line and kicking the ball toward the other team. This is a kickoff. The other team tries to catch the ball and run it back as far as possible. If the player catching the ball sees there is no hope of running it back, he raises his hand asking for a fair catch. In a fair catch, the defending team may not tackle him and he may not run with the ball. If the ball is kicked into the end zone and no one catches it or the player catching it does not run with it, there is a touchback and the first play starts at the offense's 20 yard line. Unlike a touchdown, a touchback does not score any points.

Downs: The offense has 4 plays or downs to cover 10 yards or more. A play ends when the player with the ball is either stopped or goes out-of-bounds or if the ball is thrown and missed (which is called an incomplete pass). A player is stopped when his knees touch the ground either because he was tackled by a defensive player or because he fell. When a play is over an official blows a whistle. Normally, teams try to cover the 10 yards in 3 plays or less. If they don't make it in 3 plays, they use the 4th down to kick the ball toward the other team. The ball is not placed on the ground and kicked as it is in a kickoff. Instead, the ball is snapped back to the kicker who kicks the ball. This is punting. Teams don't have to punt on 4th down. Sometimes, if the distance to complete the 10 yards is very short or if a team is far behind in the score, they elect to go for it on 4th down--to try to complete the 10 yards with another play. If they fail to make it on 4th down, the ball is turned over on downs where it ends up. On 4th down, if they are close enough to the defense's goal posts, the offense may also elect to kick a field goal. If the field goal misses, the ball is turned over to the other team where it was before the field goal attempt.

If a team succeeds in advancing 10 yards or more, they get a first down. That is, they get a new set of 4 downs to make another 10 yards.

Scoring: The object of the game is to score more points than your opponent. A touchdown is worth 6 points. After a touchdown, the team then attempts to kick the ball through the goal posts to get an extra point. Because this kick almost always works, most people think of a touchdown as being worth 7 points and then subtract a point if the extra point kick is missed. The team that scored the touchdown has the option of trying to get the ball into the opponent's end zone again in just one running or passing play instead of kicking for the extra point. If this two point conversion works, they get two points instead of just one. This is, however, more than twice as difficult as kicking an extra point.

A field goal is worth is worth 3 points.

If an offensive player is stopped in his own end zone, the defense scores a safety which is worth 2 points. This rarely happens. After a safety, the offense must kick the ball to the other team with a free kick where the kicker kicks the ball from his own 20 yard line. It's called a free kick because the kicker may not be tackled.

Diagram of players