Because of gravity, everything eventually arcs, but how can a baseball possibly "curve"?

Question

I believe a "curve" ball is an illusion, and that actually it's a well guided arc. to think a missle can move left or right without it's own source of power is to deny everything we know about physics.

nowhere in the wikipedia article does it say anything about the ball moving left or right. the friction from the stitches is inconsequential. to compare a baseball to a wiffle ball is ridiculous, and the aerodynamics of a missle without a power or directional support service is not the same thing as a jet airliner. I regal in my superiority. **It can't happen!**

Answer 1

I'm torn between what my eyes tell me...and science.
Years ago a major magazine (Life?) ran a pictorial 'debunking' of the curve ball claim complete with stroboscopic pictures. Big league players taking that third strike 'curve' must have their own ideas about the whole question.
Play ball.

Answer 2

If you follow the Wikipedia link in the first answer it has a link to what is called the Magnus effect. A thrown pitch like an airplane develops a cusion of air around it which effects how it moves and given enough force will defy gravity as long as the velocity is sufficient. A crucial aspect of the distance between the mound and home plate is how much velocity a pitcher can put on a ball. The overhand drop cuve is an example of what you are talking about. This pitch is basically placing the ball in the right place with enough velocity that gravity takes over shortly before reaching home plate thus causing an arcing of the ball.

The more typical curveball/Screwball will build up this cusion of air until it peaks some where close to home plate. If thrown too fast it "flattens" out. That is it doesn't really break. Usually those wind up as souvineers for fans. Throw it too slow and it'll break before reaching the batter and make the catcher scramble to block it. If the mound were moved back pitchers would have to throw Curveballs/Screwballs much harder to get the same effect. Move the mound in they have to reduce velocity.

Other pitches rely on the same principle to make the ball do sudden drops and even cause it to rise. A pitch I threw in HS would actually hop on air then die about the time it cross the plate.

The ball which actually defies common physics the most is a knuckleball. Nobody not even the pitcher knows where a knuckleball is going until it gets there. The physics of it is basically a knuckle ball pitcher throws a ball flat enough and with low enough velocity that it has no real cushion of air. It is at the mercy of so many variables that it's the best demonstration of a random engine in the real world. While none that I know have has come back at the pitcher I have seen knuckle balls go very wide of home plate, bounce to the catcher and make the catcher almost jump to catch it.

In short a curveball works much the same way a jet aircraft does. Using velocity ot create unequal air pressure on different sides of the ball producing effects such as lift. The lift on a curveball is however down and away from a right handed batter from a right handed pitcher.

Answer 3

I'm an professional umpire, and I can tell you first hand that the seams are the key to making the ball move, or "curve". The wind resistance against the seams when the proper grip and pressure are applied to the baseball do, in fact, cause the ball to curve in some instances. I've seen pitches that started out behind a right-handed hitter's butt and end up curving all the way across the outside of the plate and out of the strike zone. Of course gravity plays a roll; what comes up must come down. But the pitcher's ability to properly utilize the seams' interaction with wind resistance is the key to extraneous movement of the baseball.

Answer 4

It's very simple. The ball is thrown in a way that makes it spin. The spinning causes friction between the air molecules and the stitching on the ball. The friction with the air cause the ball to deviate from it's otherwise arch-shaped path. The ball ends up a few inches farther to the side than it would without the unusual spin.

Answer 5

The way you grip the ball and use the seams, when the ball travels through the air, with the right amount of "spin" on it, and the proper arm release and angle, it actually does curve.

Watch any MLB game for a little bit and you will see that it truly does curve. Better yet try to hit a curveball and you will be totally convinced that it is not an illusion.

Answer 6

It's the same concept as a hook or slice in golf. Also, a home run ball has enough back spin to make the ball actually defy gravity. That's why the ball appears to float as it peaks. Therefore the ball can have more carry if it has more spin. The threads of a baseball catch the air as it spins and moves the ball in the direction of its rotation.

Answer 7

When a picture throws the ball, he/she will put a spin on the ball. Because of the interaction of the spin and the seams of the ball with the air flowing past the ball, there becomes a difference in the air pressure on one side or the other of the ball. The ball will move in the direction of the lower pressure.

Answer 8

the seams of a ball spinning in a direction pull the ball in a certain direction via air resistance

Answer 9

I'm sure it has something to do with the spin of the ball out of the pticher's hand, differences in pressure and airflow... But I'm not smart enough to know just how that works.

Answer 10

i think it has to something to do with the way the ball spins creating air pressure differentials that makes the ball change its direction. i think it's similar to the lift effect utilized by airplanes to fly.