How Air Resistance Determines the Pitch (Basic)

To pitch a the highest level, a pitcher needs strength, flexibility, and intense focus.

When the ball is finally released, several forces act on it. First is gravity. The moment the ball leaves the pitchers hand, gravity begins to make the ball drop toward Earth. Gravity is basically the pull that an object of mass has on another object. Everything on Earth is affected by gravity. For example, a pencil you are using to take a math test has a pull on you and you have a pull on it! The only difference is that you have more mass than the pencil so you cannot feel the effects. The same is true for a baseball.Earth has an effect on the ball but also the ball has an effect on the Earth. However, the force of the ball on the Earth is not seen because of the tremendous difference in mass.

Another force that acts on the ball is air resistance. Air acts just like water! The only difference is that air is much less dense than water. This means that the microscopic air particles are much farther apart than the particles in water.  In a swimming pool, it is much harder to walk than when on land. This is because the water is providing a resistance against your body. Air provides a resistance as well but it is not felt as much because of the density differences. However, since a baseball is much lighter than you, air plays more of a role on a ball than on your body. The ball essentially must move air out of the way and this slows it down.  Imagine a skydiver opening up his parachute and falling slowly to Earth. This is exactly what happens to a baseball but on a much smaller scale.
Air resistance is also responsible for a pitcher being able to throw different kinds of pitches! When a pitcher throws a fastball, he throws it in such a manner that the spin is straight up. This will keep the ball going straight. When the pitcher throws a curve ball, he will tilt the spin so that the air resistance will push the ball in different directions (usually down or to the sides). In the case of a knuckleball, a pitcher will try to put zero spin on the ball. This will allow the air to push the ball in all sorts of directions and it appears to hitters that the ball is “dancing” through the air. This makes the pitch very deceptive and can lead to more strikeouts.

By: Kenny Morley, Ohio State University 



Zarda, B. (2008, August 06). Science of a pitching freak. Retrieved from

Free fall and air resistance. (2012). Retrieved from

Articles by Kenny Morley.

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