22 June 2012

Germany's Screwball Goal ...

Germany was much too powerful for Greece in today's Euro 2012 quarterfinal action.  Earning a 4-2 victory in Gdańsk (Poland), Germany moves on to the semifinal round against the winner of Sunday's England versus Italy match.

The goal I most enjoyed in Germany's win was the first one.  Click here for ESPN's GameCast of the match.  Click on The Team's first goal and enjoy Philipp Lahm's smash from about 22 m (24 yards) out.  Go to the 0:47 mark in the video for a great slow-motion look at Lahm's goal.  Note that Lahm hit the ball with his right boot.  Note, also, that Lahm's right leg moved powerfully across his body, meaning that he was twisting counterclockwise (as seen from above).  His twist was so strong that he lost his balance upon returning to the pitch after his brief moment in the air.  That kicking motion gave the ball a clockwise (as seen from above) component to the spin.  The video shows quite well that the ball tailed away from the Greek goal keeper, Michail Sifakis, in a left-to-right manner (as seen by Lahm) as it slammed into the upper right portion of the goal.  Without the rotation and the curve due to the Magnus force, the goal keeper would have blocked the ball (Sifakis managed to just get his left pinkie on the ball).

If a right-handed baseball pitcher throws the ball with a component of spin that is clockwise (as seen from above), we call that pitch a screwball.  Not too many pitchers throw that pitch because it is hard on the arm.  Old timers like Christy Mathewson and Carl Hubbell were famous for throwing the "fadeaway" or screwball.  From my youth, I recall Fernando Valenzuela lighting up Major League Baseball in 1981 with a look to the sky before throwing his screwball.  Today's pitchers rely more on a circle change because it is much easier to throw compared to a screwball.  Anyway, a screwball moves from left to right (as seen by the pitcher) for a right-handed pitcher.  That is the same type of motion that Sifakis had to deal with from Lahm's great kick.

The Magnus force makes for some wonderful trajectories!

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