Book 28, Question 7
Why does a knuckleball wobble?
A knuckleball is thrown with almost no spin.
Because the ball doesn't spin, the seams on its surface cause the air flowing around it to change in small, random ways, which pushes the ball one way and then another. This makes it flutter unpredictably. Even the pitcher and catcher can't be sure where it will go. Knuckleballs are thrown slowly.