Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Physics in the Game: When a Goal is Scored as if by Magic

09.02.2006


Miracles happen over and over again. Even in the sport which the Germans love the most – soccer. But when the ball flies in a curve and hits the goal it has nothing to do with magic powers. Here it is rather a question of physical powers taking effect. And these powers can be calculated. That is what Metin Tolan, professor for experimental physics at the Universität Dortmund, is convinced about. With that he clearly disagrees with Rudi Assauer who once said: “Soccer is unpredictable”.



With his special lecture during the summer term Professor Tolan is on the track of selected phenomena in soccer. In view of the World Championship the 40year-old prolongs his regular lecture about quantum mechanics by half an hour. His students can find out all about a curving cross, for example.

Tolan knows that “Balls with a strong spin fly around corners”. That is due to air friction, (head-)wind and gravitation effecting the ball. When the ball is strongly cut with a spin of about five rotations it can move five meters sideward and with ten rotations about ten meters. Physicists call this the Magnus-Effect: Overpressure pushes the ball sideward so that it flies in a curve – preferably hitting the goal. The Brazilian Roberto Carlos, for example, succeeded in doing this in a game against France in 1997. The more the ball rotates the stronger the effect.


If a curving cross is successful, however, depends on the surface of the ball. As the seams of the ball – consisting of twelve pentagons and twenty hexagons – are anything but just design. They rather provide for the strongly modified air friction. They cause the air turbulences developing behind the ball. With this knowledge one can not only shine in context with this year’s World Championship.

The basic rules of mechanics and aerodynamics also took effect on the most controversial goal in soccer history in Wembley in 1966. According to the rules it is a goal when the ball is one rotation behind the line. In the game Germany against England the ball bounced off the crossbar and flew out of the goal. The linesman counted it as a hit – and he could have been right: “It was a goal when the speed of the ball was between 75 and 100 km/h and when the cross bar gave it a spin of about ten rotations per minute. That is to say it flew in a curve and was in the air behind the line for 0.02 seconds”. That is how Tolan explains his calculations. Smiling and well-knowing that this scientific analysis can only be done without personal emotions.

Ole Luennemann | alfa
Further information:
http://www.uni-dortmund.de

More articles from Physics and Astronomy:

nachricht Pulses of electrons manipulate nanomagnets and store information
21.07.2017 | American Institute of Physics

nachricht Vortex photons from electrons in circular motion
21.07.2017 | National Institutes of Natural Sciences

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Manipulating Electron Spins Without Loss of Information

Physicists have developed a new technique that uses electrical voltages to control the electron spin on a chip. The newly-developed method provides protection from spin decay, meaning that the contained information can be maintained and transmitted over comparatively large distances, as has been demonstrated by a team from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute. The results have been published in Physical Review X.

For several years, researchers have been trying to use the spin of an electron to store and transmit information. The spin of each electron is always coupled...

Im Focus: The proton precisely weighted

What is the mass of a proton? Scientists from Germany and Japan successfully did an important step towards the most exact knowledge of this fundamental constant. By means of precision measurements on a single proton, they could improve the precision by a factor of three and also correct the existing value.

To determine the mass of a single proton still more accurate – a group of physicists led by Klaus Blaum and Sven Sturm of the Max Planck Institute for Nuclear...

Im Focus: On the way to a biological alternative

A bacterial enzyme enables reactions that open up alternatives to key industrial chemical processes

The research team of Prof. Dr. Oliver Einsle at the University of Freiburg's Institute of Biochemistry has long been exploring the functioning of nitrogenase....

Im Focus: The 1 trillion tonne iceberg

Larsen C Ice Shelf rift finally breaks through

A one trillion tonne iceberg - one of the biggest ever recorded -- has calved away from the Larsen C Ice Shelf in Antarctica, after a rift in the ice,...

Im Focus: Laser-cooled ions contribute to better understanding of friction

Physics supports biology: Researchers from PTB have developed a model system to investigate friction phenomena with atomic precision

Friction: what you want from car brakes, otherwise rather a nuisance. In any case, it is useful to know as precisely as possible how friction phenomena arise –...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Closing the Sustainability Circle: Protection of Food with Biobased Materials

21.07.2017 | Event News

»We are bringing Additive Manufacturing to SMEs«

19.07.2017 | Event News

The technology with a feel for feelings

12.07.2017 | Event News

 
Latest News

NASA looks to solar eclipse to help understand Earth's energy system

21.07.2017 | Earth Sciences

Stanford researchers develop a new type of soft, growing robot

21.07.2017 | Power and Electrical Engineering

Vortex photons from electrons in circular motion

21.07.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>