World Cup ball "suddenly seems to change its trajectory"

IA

According to Caltech scientists

They have a wind tunnel, so they must be right.

"So as the goalkeeper sees the ball coming, it suddenly seems to change its trajectory... "It's like putting the brakes on, but putting them on unevenly."

discuss

BigRedEvil

TBF I have had a kick of a replica of the ball and it is really light compared to others

addick16

the jabulani has no seams which causes the ball to swerve (like a knuckleball). The ball has panels that are heat molded together, causing the ball to seem lighter then usual.

Stefco

It seems to fly like a 'Windblower' football. The old 99p Super Tele balls in white or orange, with black panels.

Toe poke one of them, & it would swerve around like it was in a tornado, & heaven help the game if it were windy! Playing a game into the wind was a nightmare! Kick it, & it would come straight back at you. I scored a few spectacular own goals in the playground thats for sure!

kigelia

There is a better explanation here for the science behind this principle - it is nothing you and relies on something called the Reynolds critical number, essentially meaning that there is a certain point where the ball will suddenly experience a large drop (I think) in drag based on the speed it is moving and the amount of spin. I suspect a smoother, essentially more spherical, ball will be effected to a greater extent than one with a rougher surface.

colthe3rd

Isn't it allegedly the heaviest ball they have made for a world cup? How many goals has it actually caused due to it's unpredictable trajectory? Most of the goalkeeping gaffs seem to have come from shots or crosses that pose little danger, so is it more of a placebo effect?

All this talk may be having a more psychological effect on keepers than the ball behaving that much differently to "normal" balls. I would imagine most modern day balls in a wind tunnel would change trajectory suddenly.

PaddyP17

The Jabulani has eight panels compared to the standard fourteen on previous balls such as the +Teamgeist as used four years ago. Apparently the lack of stitching means trajectory is different, but not completely alien.

MrOneLung

Seeing as there are laws that govern the weight of the ball, I suggest the ball is not really lighter.

Chris_from_Sidcup

[cite]Posted By: colthe3rd[/cite]Isn't it allegedly the heaviest ball they have made for a world cup? How many goals has it actually caused due to it's unpredictable trajectory? Most of the goalkeeping gaffs seem to have come from shots or crosses that pose little danger, so is it more of a placebo effect?

All this talk may be having a more psychological effect on keepers than the ball behaving that much differently to "normal" balls. I would imagine most modern day balls in a wind tunnel would change trajectory suddenly.

That's what i think. It's not like we've seen the ball going one way then suddenly curling the other way to deceive a keeper. Didn't seem to change direction much for Tevez's or Suarez's strikes over the weekend either.