Hey everybody welcome back to explain that confide podcast. We take the questions you always wanted to ask and talk about them in a way That's easy to understand we are your hosts. I'm Tim So Kevin today We're talking about a topic because of one of our listeners Ron H who wrote in asking about golf balls The first question we have comes from Ron and that is why are standard golf balls white? Instead of a more vibrant color that's easier to see as it travels through the air with clouds as a background That's a pretty good thought provoking question first actually.
It's about history and tradition now mass-produced golf balls started off white because they covered that With latex and then they stayed that way. It's kind of a general thing Secondly golf balls are actually more important to find on the ground than they are in the air So you trade off not be able to track it in the air against a higher chances that you'll be able to find your white ball in that field You know yellow dandelions or really tall green grass I see now how do TV cameramen or camera people follow the ball so accurately then when it's flying through the air Do they have a technique to keep it center screen? Oh, well, they those people they are very skilled and they also have special lenses and some people have to describe how they could turn on the zebra stripes Which lay stripes over anything white in your viewfinder? These days there is sometimes also some computer software that helps since you've been talking about history and tradition at the start Can you explain how golf originated?
Ah, so the origins of golf are very much up for debate actually But there's some generally accepted notion that the modern game of golf was developed in Scotland from the Middle Ages onwards So the game actually did not find international popularity until something like the late 19th century And that was when it spread it to the rest of the United Kingdom and then to the British Empire and to the United States You know the word golf that we use today or in Scots of G. O. W. F.
Is Usually thought to be a Scots alteration of the Dutch cough like a COLF Basically, I meant stick or like a club or like a bat. Here's another very popular question that we get relating to golf And that is how do we determine on a golf course what the par for a hole is? Oh, yes, the par question Very important is sometimes mysterious, but basically each hole no matter the length is appropriated to strokes for puss and therefore par for the whole is all is the number of strokes It should take a golfer to reach the green then plus the two putting strokes And there are also some guidelines based on distance So some like par three means one stroke to reach the green and then the two putts and will be up to 250 yards Part four means two strokes reach green and two putts and will generally be something like 251 to 470 yards And then finally par five means three strokes to be three and two putts. Is that such thing as a par six?
You know there actually is something typically over 691 yards would be a par six I believe there's even a par seven somewhere in South Korea for a hole that's eleven hundred yards Can't believe that mm-hmm, but the way the par measurements have come together in practice is typically the reverse of what we've just been analyzing So the designers of the golf course begin with the end in mind We actually set the par and then create the whole course and it's usually based on how far a pro can drive the ball So for example a par three should be about the distance that a pro can drive the ball and then hit the green one shot Got it. That's helpful now a classic golf question. Why are there dimples on golf balls? Ah, so when the air moves over a very smooth surface You have something in physics called laminar flow And this means that the air is not bumpy.
It actually flows very smoothly across the surface You would think that such an object would move faster through the air, right? Well, actually that's not true What happens is the aerodynamic forces are you know They're lift and drag and drag can come from a lot of places We only get lift when the flow is moving over the surface. So a very laminar flow is smooth Yes But once the ball gets going fast enough the smooth flow won't stay attached to the surface of the ball And so this is something called separation and it means the ball no longer generates any lift it will just drop like a rock So how do you dimples help them? Right, right.
So back to the dimples the dimples on the surface of the ball creates something called turbulent flow at the surface And thus this lets the flow stay like attached to the ball Now this might seem counterintuitive because turbulent flow creates more friction and thus drag than laminar flow But however separation on it on its own creates a large amount of drag and preventing that separation more than outweighs the penalty of slightly higher form drag In the aerodynamic world We call this a boundary layer because the flow is very turbulent right the surface and becomes more laminar as you move away from the ball Boundary layers got it. So if we were to apply this elsewhere then why do cars not have dimples? You know in cars aerodynamic lift is not important. So it's an underflow.
That's you know generally more desirable Could airplanes benefit from having dimples like golf balls? Mmm, also not really so dimples help on golf balls because they help with the base drag and that is drag created by the low pressure region behind the We think golf balls are not aerodynamic and so have a lot of base drag and does the dimples help But airplanes are made to be very aerodynamic and have relatively more skin-fishing drag So the benefit from dimpling the skin will be negated by basically the increased drag of skin friction now while we don't have dimples on planes I believe there are still some concepts and techniques that are derived from dimples and all that we've learned today that are applied to aircraft So where can we see these effects on a plane? You are correct. So turbulent flow is very important aircraft because of that boundary layer separation is actually a very dangerous condition You may have heard it referred to as something called stall Essentially what happens is a wing or a turbine plane that is not generally lift is stalled So where do I look for how it's implemented on a plane?
So if you look out at a wing of an airplane You'll actually see lots of little jacket pieces sticking up that are meant to delay the separation over the wing and that's similar to the effect from dimples on a golf ball They are actually called vortex generators to look them up vortex generators. We will look them up. Thank you Kevin Did you learn something new if you did send us an email? We are at ELI5 podcast at gmail.com We love hearing from you, especially when you've got comments or suggestions for us and as always thank you to the community at our slash explain that five we will see you all next week