# Please explain to me the physics that allows this weird field goal to happen **URL:** \ **Category:** Factual Questions\ **Created:** [November 11, 2014, 10:51am UTC](https://boards.straightdope.com/t/please-explain-to-me-the-physics-that-allows-this-weird-field-goal-to-happen/704327 "2014-11-11T10:51:10Z")\ **Posts on this page:** 17\ **Page:** 4
**Author:** ![Colophon](https://avatars.discourse-cdn.com/v4/letter/c/f05b48/32.png) [@Colophon](https://boards.straightdope.com/u/Colophon)\ **Post date:** [November 13, 2014, 2:11pm UTC](https://boards.straightdope.com/t/please-explain-to-me-the-physics-that-allows-this-weird-field-goal-to-happen/704327/61 "2014-11-13T14:11:17Z")
> [@Dead\_Cat](#): > > Nah, I’m pretty certain it originated in baseball, it’s not commonly used in Britain - I’ve never used it to describe a curling/dipping shot in football (soccer), nor a ball in cricket. It doesn’t really exist as a concept in cricket (as far as I know), presumably because it would be hard to achieve with a legal bowling action (the arm is not allowed to bend or straighten), and in cricket most balls hit the ground before reaching the batsman, so achieving movement after the ball has hit the ground is the goal - if the ball moves in the air between the bowler’s hand and hitting the ground, that doesn’t trouble the batsman nearly as much. I’ve certainly never heard “knuckleball” used in soccer - it wouldn’t make any sense to me at all. In the UK, a shot hit with side spin to form a curving path is known informally as a “curler”, or you might say a player “curled it into the top corner”. Watch from 1:06 here for a nice illustration: [http://youtu.be/A7PlBKfInAM?t=1m6s](http://youtu.be/A7PlBKfInAM?t=1m6s) ---
**Author:** ![pulykamell](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pulykamell/32/3166_2.png) [@pulykamell](https://boards.straightdope.com/u/pulykamell)\ **Post date:** [November 13, 2014, 2:27pm UTC](https://boards.straightdope.com/t/please-explain-to-me-the-physics-that-allows-this-weird-field-goal-to-happen/704327/62 "2014-11-13T14:27:22Z")
Yeah, Youtube is full of soccer curve goals. Some are just absolutely incredible. [See here](https://www.youtube.com/watch?v=rEKGTq3onIo). I assume something similar is happening in this field goal. The position of the ball when it’s held by the placeholder and the direction of the kick and spin imparted by the foot causes it to tumble and curve in the air. (If you look at the first soccer goal in the link above, it’s a right-footed kicker doing a left-to-right curve like in the field goal.) So I’m guessing similar aerodynamic forces are at play, although I’ve not quite seen it done like that in American football. ---
**Author:** ![Telemark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/telemark/32/372_2.png) [@Telemark](https://boards.straightdope.com/u/Telemark)\ **Post date:** [November 13, 2014, 2:30pm UTC](https://boards.straightdope.com/t/please-explain-to-me-the-physics-that-allows-this-weird-field-goal-to-happen/704327/63 "2014-11-13T14:30:07Z")
> [@ZenBeam](#): > > (For the record, I don’t _know_ whether it hit near the center. That’s what I’m wondering about.) It hit pretty much where it dropped down. Balls don’t slide along the net - having watched lots of field goals and extra points where they behave exactly as described. ---
**Author:** ![pulykamell](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pulykamell/32/3166_2.png) [@pulykamell](https://boards.straightdope.com/u/pulykamell)\ **Post date:** [November 13, 2014, 2:30pm UTC](https://boards.straightdope.com/t/please-explain-to-me-the-physics-that-allows-this-weird-field-goal-to-happen/704327/64 "2014-11-13T14:30:48Z")
And [this soccer kick](https://www.youtube.com/watch?v=ot_Ruj9f8eE) is more what I would describe as a “knuckleball.” Note in the slo-mo how there is no spin whatsoever on the ball. Like the baseball knuckleball, this makes the ball move rather unpredictably in flight, whereas with a curve, you can deduce its trajectory based on its spin. ---
**Author:** ![CurtC](https://avatars.discourse-cdn.com/v4/letter/c/ce73a5/32.png) [@CurtC](https://boards.straightdope.com/u/CurtC)\ **Post date:** [November 13, 2014, 3:00pm UTC](https://boards.straightdope.com/t/please-explain-to-me-the-physics-that-allows-this-weird-field-goal-to-happen/704327/65 "2014-11-13T15:00:36Z")
> [@Colophon](#): > > I’ve certainly never heard “knuckleball” used in soccer - it wouldn’t make any sense to me at all. In the UK, a shot hit with side spin to form a curving path is known informally as a “curler”… A knuckleball is not one that curves due to its spinning - a knuckleball is thrown with NO spin, which is really hard to do, and it makes the ball dance in multiple directions in flight due to the airflow over the baseball’s stitched seams. The reason it’s called a knuckleball is the way the pitcher holds it while throwing - the ends of his fingers are curled over, so the fingernails are in contact with the ball, and it looks almost like he’s trying to hold it with the knuckles on the back side of his fingers. Like this: [http://espn.go.com/photo/2012/0911/ny\_u\_dickard\_cr\_576.jpg](http://espn.go.com/photo/2012/0911/ny_u_dickard_cr_576.jpg) ---
**Author:** ![ZenBeam](https://avatars.discourse-cdn.com/v4/letter/z/3ab097/32.png) [@ZenBeam](https://boards.straightdope.com/u/ZenBeam)\ **Post date:** [November 13, 2014, 3:48pm UTC](https://boards.straightdope.com/t/please-explain-to-me-the-physics-that-allows-this-weird-field-goal-to-happen/704327/66 "2014-11-13T15:48:45Z")
> [@Telemark](#): > > It hit pretty much where it dropped down. Balls don’t slide along the net - having watched lots of field goals and extra points where they behave exactly as described. They _usually_ behave like that. They also _usually_ don’t hook as much as this one appeared to. ---
**Author:** ![Telemark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/telemark/32/372_2.png) [@Telemark](https://boards.straightdope.com/u/Telemark)\ **Post date:** [November 13, 2014, 3:52pm UTC](https://boards.straightdope.com/t/please-explain-to-me-the-physics-that-allows-this-weird-field-goal-to-happen/704327/67 "2014-11-13T15:52:11Z")
> [@ZenBeam](#): > > They _usually_ behave like that. They also _usually_ don’t hook as much as this one appeared to. Plenty of balls hook that much, they just don’t usually go through the uprights. Balls don’t really slide along the net. ---
**Author:** ![Lightnin](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lightnin/32/180_2.png) [@Lightnin](https://boards.straightdope.com/u/Lightnin)\ **Post date:** [November 13, 2014, 3:59pm UTC](https://boards.straightdope.com/t/please-explain-to-me-the-physics-that-allows-this-weird-field-goal-to-happen/704327/68 "2014-11-13T15:59:01Z")
Somewhere there’s a telekinetic 49ers fan who used his powers to win a bet. ---
**Author:** ![DooWahDiddy](https://avatars.discourse-cdn.com/v4/letter/d/e9bcb4/32.png) [@DooWahDiddy](https://boards.straightdope.com/u/DooWahDiddy)\ **Post date:** [November 13, 2014, 3:59pm UTC](https://boards.straightdope.com/t/please-explain-to-me-the-physics-that-allows-this-weird-field-goal-to-happen/704327/69 "2014-11-13T15:59:47Z")
> [@spifflog](#): > > Except if like many here, you’ve watched, over 500 football games in your life, and you’ve seen 2,000 footballs hit the net and immediately fall to the ground. It’s obvious to virtually everyone here. I mean, that’s the thing. There seems to be a disconnect between the people who watch a lot of football and the people who don’t. It’s so obvious to me that I’m wondering why this is even an argument. Just to clarify my position: He’s kicking it from center field. If you pause the video right after he kicks it, you’ll see it take off toward the left goalpost. Then it suddenly starts to curve to the right at a pretty extreme angle (which is what is so impressive). Then, and only then, does it pass through the goalpost and hit the net. It is now lined up with the guy holding a kid who raises his right arm (to the left of the guy in the 52 shirt–his left), and falls straight down to the ground without moving to the left or the right. Then the announcers freak out and the 49ers win. 🙂 ---
**Author:** ![CurtC](https://avatars.discourse-cdn.com/v4/letter/c/ce73a5/32.png) [@CurtC](https://boards.straightdope.com/u/CurtC)\ **Post date:** [November 13, 2014, 4:22pm UTC](https://boards.straightdope.com/t/please-explain-to-me-the-physics-that-allows-this-weird-field-goal-to-happen/704327/70 "2014-11-13T16:22:06Z")
> [@DooWahDiddy](#): > > I mean, that’s the thing. There seems to be a disconnect between the people who watch a lot of football and the people who don’t. It’s so obvious to me that I’m wondering why this is even an argument. I watch very little football, but it seems obvious to me as well. However, I understand what ZenBeam is saying, and I’d like to have a way to prove his idea wrong. I may have to sign up for that free trial of a for-pay web site that SlackerInc referred to. ---
**Author:** ![Quercus](https://avatars.discourse-cdn.com/v4/letter/q/7ab992/32.png) [@Quercus](https://boards.straightdope.com/u/Quercus)\ **Post date:** [November 13, 2014, 8:25pm UTC](https://boards.straightdope.com/t/please-explain-to-me-the-physics-that-allows-this-weird-field-goal-to-happen/704327/71 "2014-11-13T20:25:30Z")
As far as a ball seeming to suddenly hook to one side, it’s worth noting what you’ll see if you’re standing behind a ball after it’s kicked towards a target downfield, and the ball is aimed slightly left of the target but curves to the right with a constant curve (so that it would make a perfect circle if it could keep going and going without hitting the net or falling to the ground or anything). From your point of view as you watch the ball while lining up with the target, the ball will move slowly to the left , then slowly back to the right, then faster and faster to the right. (draw a picture if it’s not clear why). And with our less then perfect perception, it will often seem like the ball is suddenly moving faster to the right, even though it’s just gradually moving faster to the right. So a ball that looks like it suddenly hooks right may not really be doing anything physically strange at all. ---
**Author:** ![newme](https://avatars.discourse-cdn.com/v4/letter/n/e0b2c6/32.png) [@newme](https://boards.straightdope.com/u/newme)\ **Post date:** [November 13, 2014, 11:31pm UTC](https://boards.straightdope.com/t/please-explain-to-me-the-physics-that-allows-this-weird-field-goal-to-happen/704327/72 "2014-11-13T23:31:04Z")
> [@Quercus](#): > > As far as a ball seeming to suddenly hook to one side, it’s worth noting what you’ll see if you’re standing behind a ball after it’s kicked towards a target downfield, and the ball is aimed slightly left of the target but curves to the right with a constant curve (so that it would make a perfect circle if it could keep going and going without hitting the net or falling to the ground or anything). From your point of view as you watch the ball while lining up with the target, the ball will move slowly to the left , then slowly back to the right, then faster and faster to the right. (draw a picture if it’s not clear why). And with our less then perfect perception, it will often seem like the ball is suddenly moving faster to the right, even though it’s just gradually moving faster to the right. > > So a ball that looks like it suddenly hooks right may not really be doing anything physically strange at all. [I drew the picture](https://www.dropbox.com/s/eepqbrsdu1gzmh5/football.jpg?dl=0), with the ball traveling in a hypothetical circle 200 yards in diameter. In the first 1/3 of the ball’s flight, it moves left about 1 yard. In the second 1/3, it moves back to the centerline, so 1 yard to the right. In the final 1/3, it moves a further 2.5 yards to the right, striking the net nearly behind the right goalpost. ---
**Author:** ![zoid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/zoid/32/336_2.png) [@zoid](https://boards.straightdope.com/u/zoid)\ **Post date:** [November 14, 2014, 12:21am UTC](https://boards.straightdope.com/t/please-explain-to-me-the-physics-that-allows-this-weird-field-goal-to-happen/704327/73 "2014-11-14T00:21:34Z")
> [@newme](#): > > [I drew the picture](https://www.dropbox.com/s/eepqbrsdu1gzmh5/football.jpg?dl=0), with the ball traveling in a hypothetical circle 200 yards in diameter. > > In the first 1/3 of the ball’s flight, it moves left about 1 yard. > > In the second 1/3, it moves back to the centerline, so 1 yard to the right. > > In the final 1/3, it moves a further 2.5 yards to the right, striking the net nearly behind the right goalpost. Now I am finally convinced we need a “Like” button 😃 Only on the Dope. ---
**Author:** ![Quercus](https://avatars.discourse-cdn.com/v4/letter/q/7ab992/32.png) [@Quercus](https://boards.straightdope.com/u/Quercus)\ **Post date:** [November 14, 2014, 2:51pm UTC](https://boards.straightdope.com/t/please-explain-to-me-the-physics-that-allows-this-weird-field-goal-to-happen/704327/74 "2014-11-14T14:51:23Z")
> [@newme](#): > > [I drew the picture](https://www.dropbox.com/s/eepqbrsdu1gzmh5/football.jpg?dl=0), with the ball traveling in a hypothetical circle 200 yards in diameter. > > In the first 1/3 of the ball’s flight, it moves left about 1 yard. > > In the second 1/3, it moves back to the centerline, so 1 yard to the right. > > In the final 1/3, it moves a further 2.5 yards to the right, striking the net nearly behind the right goalpost. Brilliant!! ---
**Author:** ![SlackerInc](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/slackerinc/32/275_2.png) [@SlackerInc](https://boards.straightdope.com/u/SlackerInc)\ **Post date:** [November 14, 2014, 3:00pm UTC](https://boards.straightdope.com/t/please-explain-to-me-the-physics-that-allows-this-weird-field-goal-to-happen/704327/75 "2014-11-14T15:00:02Z")
I too want a “Like” button! H/t also to \*\*Quercus \*\*for the idea. That is a really interesting optical effect and an interesting point about what could be going on here. I still wonder though why it is so rarely seen? Another “Like” for this “literal LOL” post: > [@Lightnin](#): > > Somewhere there’s a telekinetic 49ers fan who used his powers to win a bet. Now I’m picturing the guys from that movie _Chronicle_: “Dude! Don’t make it so obvious–you’re going to get us caught.” ---
**Author:** ![penultima\_thule](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/penultima_thule/32/3833_2.png) [@penultima\_thule](https://boards.straightdope.com/u/penultima_thule)\ **Post date:** [November 14, 2014, 10:48pm UTC](https://boards.straightdope.com/t/please-explain-to-me-the-physics-that-allows-this-weird-field-goal-to-happen/704327/76 "2014-11-14T22:48:34Z")
[quote=“Cugel, post:36, topic:704327”] Here’s a bit of Johnathan Thurston’s work with the curving “rugby” ball (he plays league) [/QUOTE] The really interesting one is at 1:30 of that clip. Thurston is a right footer and therefore his usual action is to hook from right to left. He will use that action even when he is wide out on the right. In the example at 1:30 he deliberately kicks inside the line which imparts the spin causing the left to right slice, which is what you see in the field goal in the OP. ---
**Author:** ![SlackerInc](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/slackerinc/32/275_2.png) [@SlackerInc](https://boards.straightdope.com/u/SlackerInc)\ **Post date:** [November 15, 2014, 7:15am UTC](https://boards.straightdope.com/t/please-explain-to-me-the-physics-that-allows-this-weird-field-goal-to-happen/704327/77 "2014-11-15T07:15:39Z")
Great video. I wonder why we don’t normally see that happen in football? [Previous page](https://boards.straightdope.com/t/please-explain-to-me-the-physics-that-allows-this-weird-field-goal-to-happen/704327.md?page=3)