 So now that we understand the general ways that the clock works and how the timing of the game is run, let's take a look at another important aspect of timing of the game and this aspect is called the play clock. So the play clock is much like a shot clock is in basketball, which is to say it forces the team on offense to continue playing, or maybe a better way to say it is that it prevents the team on offense from getting a lead and then simply standing there with the ball to run out the clock for the rest of the game. What fun would that be, right? So the play clock kind of forces both teams to move forward to continue to play. So typically the play clock will be 40 seconds long, which means that from the time that play ends from the time a player is tackled or the ball carrier is pushed out of bounds, that team then has 40 seconds to snap the ball to begin the next play. So as I said, that prevents a team from just wasting unnecessary time, but it will give them adequate time to regroup to call the next play and then begin that next play. If the team does fail to snap the ball after that the play clock has expired, they will be called for a delay of game penalty. They will result in a five yard penalty and so the ball will be moved back for the next play. So we'll look at penalties and have all those work in the next few upcoming videos. So typically 40 seconds is the play clock for each play. There are a few exceptions on that for things like a penalty, should be a foul, or if generally if the game, if you're watching it on TV, oftentimes the game will go to a commercial for certain things. And then whenever the game comes back, things like turnovers, so maybe an exchange has taken place. So let's say that the defensive team has intercepted the ball, so then that would then mean that the team that was on defense would become the offensive team. So they would take a break, they would allow the offensive players to come onto the field and then for the other team the defensive players, and so typically if that game is on TV then there would be a commercial while all that is happening. When they come back from the commercial, it's not necessary to give that offensive team 40 seconds to start their first play because we kind of assume that they've had that time out, the time when the commercial was taking place to regroup to kind of know what they're going to do and to get onto the field. So in that case, the play clock would be shortened to 25 seconds, but really it's kind of all the same things apply, you still need to snap the ball before that time has expired to start that next play, and then of course on the next play you would just go back to 40 seconds for the play clock, but that's basically how the play clock works.