All regulation golf balls have dimples, but not all dimples are created equal. Golf balls have dimples of different sizes, shapes and patterns, all with the same overall purpose. The dimples make the balls go farther and zoom through the air with better stability than they would if they were smooth.
The Simple Answer
Dimples achieve their task of increasing the distance and stability of the golf ball in two ways, the Knetgolf website and the K-8 Aeronautics Internet Textbook explain. Dimples both decrease the air resistance around the ball and increase the ball's lift. It takes quite a number of dimples to succeed at this, and most golf balls have 300 to 500 of the little recesses. While such a simple answer explains the overall result, it does not explain how the dinky dimples go about achieving these feats.
Air Flow Details
As a ball blasts through the air, it creates an air flow. A smooth ball creates an air flow that has wide separations behind it, which increases the drag pressure on the ball. This means the air flow is working against the ball as quickly as it can to stop its progress. A ball with dimples creates an air flow that has narrow separations behind it, the textbook explains, which decreases the drag pressure on the ball and lets the ball fly farther on its path.
Lift Details
Golf balls fly through the air with backspin, where the ball is rotating back toward the golfer as it moves away from him along its trajectory. When a ball with dimples has backspin, the dimples make the air currents above the ball move more quickly than they would on a smooth ball. This increased speed of the top air currents decreases the air pressure above the ball. The ball therefore lifts higher because less pressure is bearing down on it.
Dimple Differences
At a glance, all golf balls might appear to have identical dimples, but dimples come in varying configurations. Knetgolf cites examples in the octahedral 392-dimple configuration and the icosahedral 432-dimple configuration. The former features 392 dimples in a pattern that features six concentrations of deeper, larger dimples spaced at right angles from each other around the ball. The latter has 432 dimples with concentrations of larger, deeper dimples at 45-degree angles from each other spaced around the ball.
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