I just wanted to post a clarification to my previous post on the historic weight of the official football.
The Jabulani ball’s dry weight is 440g. That’s 15.52 oz. (Typo corrected – Thanks to @darcysarto)
You’ll recall that since 1937, Law 2 has specified the dry weight of the ball. It has to be between 14 and 16 oz. Thus, in terms of the dry weight of the ball, the Jabulani is at the high end of what’s permitted.
This is not to deny two things:
- Issues about the flight of the Jabulani ball and how easy it is to predict that flight. Clearly the new ball is different in terms of aerodynamics from the balls of 10, 20, 30 or 70 years ago. But most commentary on the matter seems to assume that the primary difference with this ball from its predecessors is its weight. It isn’t. The flight of the ball is all to do with shape. Don’t forget that most of the complaints are comparing the Jabulani ball with other recent modern balls that were subject to the same complaints in their turn.Â
- Previous balls taking on weight from accumulated moisture. Modern balls are better at staying dry. This means that on a wet pitch, a 1937 ball was very likely to finish 90 minutes heavier than it began. Furthermore, the 1937 ball would most likely stay on the pitch for the whole game – something that cheap, reliable football production has rendered unnecessary. Pace Dearieme, not every football match in the black-and-white era took place on a mud pudding. More Mitchell and Kenyon films show dry, dusty, grassless surfaces than soaked ones, and in such circumstances, the weight of the ball would be the same – or even lighter – than it is now.
How much drier is a Jabulani ball compared to, say, the balls at France 1998? For a size 5 ball, FIFA requires that it not take on more than 10% of its dry weight during official water absorption testing. The Jabulani ball, so the test results claim, takes on no extra weight at all. (FIFA’s actual criteria are slightly more complicated than I’ve described, but that’s the gist). But every World Cup ball from the Adidas Etrusco Unico of 1990 on has been completely water resistant. It’s not weight: it’s aerodynamics. And old men forget: former players, now commentators, talking about “new lighter balls” are giving people the wrong idea.
Given that many of the matches at the 2010 World Cup have taken place in torrential rain, it’s interesting to speculate just how much would have been different had traditional materials been used for balls, boots and shirts. You can find out for yourselves: get your shirts here, and your ball here. I’ll be Holland, and you can be Uruguay.
UPDATE: Alive and Kicking are right: the South African World Cup should have used their leather footballs – hand stitched in Africa and providing African jobs. Read more about Alive and Kicking Here.
8 Replies to “Weight and the Jabulani Ball”
When our nipper was young I bought her a “football”, a light, plastic, very spherical, very smooth object. I found that I could kick it so that in flight it swung first one way and then the other. This seemed to me to be absolutely contra the received wisdom of why balls swing in flight. I decided in the end it was probably because it distorted from sphericity when I kicked it and recovered its shape in flight. And then it occurred to me that the pseudo-scientific accounts I’d read about swinging balls (shut up at the back) treated the ball as rigid. I suppose I should enquire just how wind-tunnel testing of footballs is done – it’s insufficient (I suggest) to set them up, spinning, in an airstream. You need also to mimic the impact of boot on ball. But perhaps they do that anyway.
Oh yes, and it also occurred to me that if I could make it double-swing in the horizontal plane, it could also probably be made to double-swing in the vertical plane, though it wouldn’t be easy for the kicker to see that. A camera located at the side should pick it up though. In short, if I had kicked that ball with lots of topspin, would it initially have risen faster than I expected and then, on recovering its shape, have dipped?
It’s just occurred to me: you could design a football that’s heavier than permitted and then sneak it under the limit by inflating it with hydrogen. That way the ball would have more weight concentrated at its outer radius and you could probably exploit spin more. The effect, to be fair, might be minor, but I’ll happily accept a research grant to investigate. Anybody?
To be clear, my previous comments weren’t intended as contradictions to your point about weight, I’m just fascinated by the question of the ball being different – and that last blog was a convenient place to post for an erudite audience. I’m fascinated because:
1) I used to be an aerospace engineer who did a lot of work on aerodynamics…
2) I think there’s a particular moment from the Algeria game, seared on my memory, England are breaking forward – Lampard(?) passes the ball at speed between two Algerian players towards Rooney who has his back to goal (thus facing the incoming ball.) Rooney sticks out his leg to cushion the incoming pass, and it bounces off by about 2 yards…
3) A lot of the comedy defending has involved balls bouncing off defenders at odd angles – and of course there’s been quite a few goalkeeping travails. It’s also felt to me that there have been more shots off target (and over the crossbar) than usual.
4) Recent comments by a friend – “this WC has shown how far below Champions League quality national teams are” – I’m not as convinced as he is, I think some of the comedy defending in particular may be ball induced. (However some of his point surely stands and I’d be interested to hear your views, James… in the age of defensive drilling, temporary teams like national sides can’t reach the fluency of a Mourinho Inter?)
Thanks for straightening out my misconceptions on this. It also surfaces another (again, possibly faulty) sepia-tinted truism from my youth.
You know the one, the golden age of British goalkeeping (largely English, but we must include Pat Jennings). In my mind’s eye, Banks, Jennings, Shilton, Clemence, Parkes, Rimmer, Corrigan, et al were in all respects superior to their continental counterparts.
That universal superiority, however, was expressed best in a single act: that of catching the ball where their European colleagues would have punched it. Nowadays, of course, no keeper trusts the flight of any modern ball sufficiently to attempt a clean catch, except for the tamest of shots.
So, James, what do you think? Were we really pacesetters in goalkeeping at that time? Whilst club sucess in European competition might support the idea, England’s failure to qualify for the World Cup in 74 and 78 suggests otherwise.
Thanks once again for the mental stimulation.
@metatone; the pundits kept saying that Germany’s centre backs were feeble, but I thought they did quite well, especially the tall lad Meerkatshagger.
@dearieme – you challenge anyone to play that well with a meerkat stuffed down their shorts?
Perhaps it’s a meerkat metaphorical? Or perhaps it’s like the meerkat in the insurance ad, and just adds to the German team’s diversely Slavic background.
Anyway, the Germans were a fine sight, giving the impression of a team organised so that it got the max out of the individuals. Unlike some…..
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