A knuckleball's movement principales are very much the same w as a curveball. The less spin on the ball the more it moves-tghis also accounts for the ridiculas speeds at which it travels.

Now, the ball is travelling forward at 60mph. The air resistance on the ball is varied depending on where it is. At the stiches the air is going to travel around the ball slower, causing the ball to rotate slightly. As it does, it moves and changes direction. However because it has rotated only slightly the same thing happens to the opposite side of the ball. Making it change directions again, the other thing that makes it so hard to hit is that, with the constant change in speeds and direction, the ball sinks aswell. These thing are why the knuckleball is so hard to hit and even pitch, as the pitcher does'nt even know where its going!

The reason a knuckleball goes in any direction is because the stiches on the ball creates air pockets.The air will travel slower as it is going around the ball because it has air resistance. The high pressure will be trying to get to the low pressure which is how the pitcher munipulates the air, along with the way the pitcher throws the ball. This all has to do with flight and science.

Basically a really slow pitch that you propel somehow so that it gets enough of a push that the air currents can affect it. There are lots of ways to throw it, it's basically whatever a pitcher can get to work for him. I throw mine with the index and middle fingers together on top of the ball between the narrow seams and the other fingers on the sides of the ball. This is one of 2 popular ways to throw the pitch, the other involves digging the fingernails into one of the wide seams. Whatever method you choose to use, the pitch seems to always involve pushing the baseball away with at least 2 fingers and the thumb, some have used the term "flicking" to describe the motion. I myself push the ball away with the index and middle fingers and get that thumb pushing it away as well, the thumb is critical by the way to the action of this pitch. I know someone else who throws the pitch like a palmball, with all fingers on top of the ball except the thumb which is underneath and pushes the ball away with all the fingers. However, the principles of throwing it seem to stay the same, throw it slow, propel it with the fingertips somehow, including the thumb, and hope you can get it close to the strikezone. And if you really want some serious knuckleball discussion go to the Knuckleball forums, the best collection of online Knuckleball lore you're going to find. Here's the link, http://www.oddball-mall.com/knucklertalk/index.php

http://www.slb.com/seed/en/watch/baseball/physics.htm

The fingertips are pushed into the ball so that the knuckles grip the ball very tightly. When the ball is released, the fingers are popped out, in the effort to propel the ball towards the plate without any spin. This pitch relies on the natural air currents to push on the seams of the ball as it floats towards the plate without any spin. This can cause the ball to do virtually anything in terms of direction of movement. The knuckle ball is an extremely slow pitch, but can be very effective due to its lack of predictability. Batters have a very hard time hitting this pitch, but it is extremely hard to control. There are only a few successful knuckleball pitchers playing professionally today.