Throwing a Baseball

So, we all understand the concept behind throwing a baseball. Palm the ball with a firm, but not too hard grip, then throw it with as much force possible at the catcher. In proffesional games, and even on the collegiate and little league levels, pitchers have become so efficient at their sport that they have developed different pitching techniques to alter the trajectory of the baseball.


At the base of these various techniques is the curveball. By altering one's grip, the baseball leaves the pitchers hand spinning in the direction of the pitchers choosing. The different grips the pitcher utalizes all offer different types of spins that the ball will move during flight. These various pitches have been named over the years, often according to the type of trajectory the ball will follow.

This link offers a few examples of the various types of pitches.
http://www.thecompletepitcher.com/different_baseball_pitches.htm


So, why does putting a spin on the baseball change the path it will take from the pitcher to the catcher? Interestingly enough, it manipulates the same laws of physics that an airplane does to gain flight. The airplanes wings are created so that the air on top of the wing has to move a greater distance in the same amount of time as the air on the bottom of the wing. This creates lower air pressure on the top of the wing, giving the plane it's lift.

Now let's inspect the trajectory of a curveball. When it leaves the pitchers hands, it is given a spin. Imagine that the ball is traveling from the right to the left. If you don't understand, then perhaps this awesome little text/image/thing will help.

Catcher <-----Ball----- Pitcher

Because of the spin given by the pitcher, the ball travels with a clockwise rotation the whole time it is in flight.

-------->

.........

.. ..
.. Poorly ..

.. Drawn ..

.. Baseball ..

.. ..

.........

<--------

This rotation, in combination the trajectory of the ball from the pitcher to the catcher, makes it so that the air on the bottom of the ball has to move faster than the air on the top. This means the ball will curve downwards as it travels.

This curve can be altered based on the positioning of the pitcher's grip.

Can you think of any other objects who's path through the air are altered because of its spin or rotation?