Why Do Golf Balls Have Dimples?


There are all kinds of balls used in sports,
with different sizes, shapes, and designs, depending on the sport’s needs and history. But there’s something especially weird about
golf balls: their dimples. There are more than 300 dimples on a standard
golf ball, and they’re there for more than just aesthetics. Dimpled golf balls can fly almost twice as
far as they would if they were smooth. In the mid-19th century, players noticed that
old-scratched up golf balls flew farther than new, polished spheres. So they started carving grooves into their
golf balls to make them fly better. By 1930, after years of trial and error testing,
the golf ball had evolved into the familiar dimpled shape we know today. It might seem kind of strange that a rough
surface would make golf balls fly better, and at the time, they didn’t know why it
worked. They just knew that it did. But these days, we know the dimples work because
of a trade-off: increasing one type of air-resistance leads to a huge decrease in another. There are two main kinds of air resistance:
surface friction and pressure drag. Surface friction works a lot like friction
between solid objects — air rubs against the sides of an object, slowing it down. Generally, the more surface area something
has, the more surface friction it creates, so giving a golf ball a rough surface does
increase surface friction. But it also affects the second kind of air-resistance:
pressure drag. As the ball flies, it pushes air out of the
way, creating a wake — a cone-shaped pocket of low pressure behind the ball, which sucks
it backward and slows it down. You can experiment with wakes if you paddle
your hand through water at different angles. If you lead with your palm, you’ll see a
big triangular wake behind your hand, and you’ll notice that it becomes much more
difficult to move your hand through the water at higher speeds. But if you turn your hand sideways, the wake
becomes much smaller, and your hand passes through the water much more easily. In a golf ball, dimples reduce the size of
the wake by creating a layer of what’s called turbulent flow. The uneven surface messes up the smooth path
of air around the ball, making it much harder for the wake to form into a clean cone. With its smaller wake, a dimpled golf ball
doesn’t get sucked backward as much, so it flies farther. So, golf balls have dimples to mix up the
air around the ball causing the wake to collapse more quickly, which allows the ball to fly
faster for longer. Of course, culture is a big part of the equation
too. Tennisballs get this effect by being fuzzy
and Footballs would do better with dimples, but have to settle for laces. Thanks for asking, and thanks especially to
all of our patrons on Patreon who keep these answers coming. If you’d like to submit questions to be
answered, or to get other rewards, like access to an exclusive monthly livestream, just go
to patreon.com/scishow. And don’t forget to go to youtube.com/scishow
and subscribe!

100 thoughts on “Why Do Golf Balls Have Dimples?

Leave a Reply

Leave a Reply

Your email address will not be published. Required fields are marked *