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Compression vs. Deformation and Other Words

post #1 of 22
Thread Starter 

Recently someone I generally like in the golf business sent a tweet about achieving "compression." I replied back, with a smiley to indicate that I wasn't being too serious, that he truly meant deformation, as the golf ball doesn't actually "compress" against the clubface very much. It was an attempt at joking around a bit that failed miserably. I may have needed more than a smiley to indicate that I wasn't being super serious. :-)

 

At any rate, a golf ball doesn't truly get any denser when it hits the clubface. It doesn't really "compress" much, but it does deform. It's a little bit pedantic, but I have a reason beyond "it's more correct" in preferring "deformation" over "compression." I'll get into that shortly.

 

Because, though the discussion that followed was not quite what I'd anticipated, it did spur this little article. For that I'm thankful.

 

A few years ago @david_wedzik, myself, and others decided that we were tired of telling people to hit draws that finish at the target with an "open" face. The commonly used words "open" and "closed" don't make sense to people in the context of curves. It confused people. Not everyone - not even the majority - but enough that we felt it mattered. When someone says "open" it often seems to imply that the face is open to the path, so we started to use the words "right" and "left" to relate things to the target, and "open" and "closed" only when talking about face-to-path relationships. Thus, good draws became shots played with a clubface that points right of the target with a path farther to the right or a right-pointing face that's also closed to the path. (We prefer the former, typically, though sometimes we'll use the words "inward" and "outward" as in "with a path that's more outward [to the right] than the face".)

 

The terminology we use is important. Though "compression" is relatively low on my list of misused words, I have taken 20 seconds to explain to students that I prefer the word "deformation" and why. Almost all of those conversations take place outside of a lesson, when a student is just asking a question about what "spin loft" is or how to read a FlightScope report or something. In the context of a lesson, where my goal is to get them to DO something, I don't mess with tangentially related "knowledge. In a lesson, I'll often just say something like "you hit that one more solidly," bypassing the potential for misunderstanding "compression" and skipping the 15-20 seconds it might take to explain why I just said "deformation" and why that's the more correct term.

 

Is there really that big of a difference between the words "compression" and "deformation"? Don't most golfers know what you mean by "compression"? What's my problem with the word "compression"?

 

My problem is that "compression" remains a word students misunderstand more than I like. More students than I prefer seem to believe compression is not just "squeezing the ball against the clubface" but also "squeezing the ball against the ground" as well. It seems to be too similar to "trap the ball" against the ground, or "pinch it against the ground" for some golfers. I've rarely heard of someone talking about "compressing" their drivers better. Whether it has to do with the sound or the fact that golfers know they should be hitting down with their irons and taking a divot, or a combination of the two or other concepts, golfers seem to relate "compression" to "hitting down" more than I like. With a driver, for example, you can often increase deformation by hitting up! The same is true of an iron - you can often increase deformation by hitting down less!

 

During the conversation, I was called a hypocrite (by a third party) because I mentioned that the main point of communication is to be understood, and to that end, I'll use the words "side spin" during a lesson if the student knows what it means and it moves the lesson forward.

 

It's not hypocritical at all, though, as there are two modes of communication. During a lesson, anything goes. My purpose is to get the student to DO something. I'll use the word "perflugenkop" if that makes sense to the student and gets them doing or feeling the proper things. Outside of a lesson, I often have time to explain what a word means, and you can engage in the pursuit of pure "knowledge" with a student. Inside the lesson, it's about performance. Who cares if they learn during the lesson that a ball isn't really "compressed" but actually "deformed"? That's a waste of time during a lesson, and likely distracts from what you're trying to get the student to DO. "Side spin" makes sense to people during the context of a lesson, so I'm not going to pause a lesson, force their brain to switch modes (task switching is costly), and explain how golf balls only have one spin and it's oriented around an axis and that's what actually makes a ball curve… Outside of a lesson, if a student wants to know, that might be fine. And with students that know, we'll talk about how their spin axis was 2° too much on that last swing… Inside the lesson, if "that ball had too much side spin because you didn't do whatever" makes sense, I go with it.

 

There are other examples of words we prefer to use over other, lesser words. For example: "straighten the rear knee." We used to say this, but "straight" is a binary state - something is either "straight" or it's not, kind of like being pregnant - you either are or you aren't. As we don't often want golfers to truly have straight legs during their backswing, we switched up to saying "decrease flex" or "extend" (or "stretch").

 

At the end of the day, I want to use words that mean the correct thing - I want to communicate effectively - and I want to use the best words when possible. During a lesson, sometimes the best words are the ones the student understands and which moves the lesson along. Outside of a lesson, sometimes the best words are the more accurate words, as you have time to explain them and talk about them a bit.

 

Does Twitter afford the option to talk about "deformation" versus "compression?" Perhaps not. Am I always perfect on Twitter, or when talking with students? Definitely not. But I strive to be, and Twitter is definitely outside the context of a lesson, the "better" words are, IMO, the words that are most accurate and which cause the least confusion. I'd rather someone have to look up what I mean (or ask me) than to take what I mean incorrectly.

 

There are no solid lines here, just a big grey area. If everyone strives to make the way we communicate more clear, we're headed in the right direction.

 

And that's how Sue C's it. :-) 

post #2 of 22

Nice post.  I believe it is critically important to alway use the correct terminology.  If we don't, then eventually the incorrect becomes correct.  A good example was the end of the last millennium being a year off because party goers and marketing types couldn't do the math.

 

I believe you stated in a previous post on this subject that impact should be approximated as an elastic collision.  This is of course a correct assumption.  The ball does lose some energy due to deformation, but it is still a good estimate.  If the ball were truly compressed, it would lose a significant amount of the energy transferred as would happen if you tried to hit a lime with a six iron.  

 

Most people who would gripe about using the correct terms are either too lazy or ignorant to understand them.

post #3 of 22
Thread Starter 
Quote:
Originally Posted by boogielicious View Post
 

I believe it is critically important to alway use the correct terminology.

 

I hesitate to say always like that. For example, the "side spin" example above. We both know what he "means" when he says "that one had more side spin" and it's not worth getting into the details during a lesson on what side spin means. I am more likely than some instructors to talk with that student outside the lesson, about spin axis tilt, and so on… but then again only if that feels right to me (i.e. are they a 2 handicapper who is likely to be using the FlightScope, or a beginner just trying to get the ball in the air?).

 

I'm not sure your lime example is great, as I don't know that a lime truly compresses either. The skin just explodes so the deformation causes quite a bit of energy loss in all directions, rather than the entire golf ball rebounding, with the net effect being forward. A cotton ball definitely "compresses" though, as would foam and some other materials. Golf balls don't compress much - they don't get denser (by occupying less space while having the same mass) - but they deform quite a bit. More deformation ~= higher smash factor.

post #4 of 22

I'm sure I use plenty of technically incorrect terms when talking about golf, or anything else, all the time. Sometimes I'm pretty sure I'm the only one that knows what I'm trying to say.

 

That said, it always has and always will make me cringe just a little when I hear people that should know better talk about compressing the ball and pinching it between the ground and the clubface.

 

Even when I knew absolutely nothing about golf I could figure that didn't happen on a golf shot.

post #5 of 22
Quote:
Originally Posted by iacas View Post
 

 

I hesitate to say always like that. For example, the "side spin" example above. We both know what he "means" when he says "that one had more side spin" and it's not worth getting into the details during a lesson on what side spin means. I am more likely than some instructors to talk with that student outside the lesson, about spin axis tilt, and so on… but then again only if that feels right to me (i.e. are they a 2 handicapper who is likely to be using the FlightScope, or a beginner just trying to get the ball in the air?).

 

I'm not sure your lime example is great, as I don't know that a lime truly compresses either. The skin just explodes so the deformation causes quite a bit of energy loss in all directions, rather than the entire golf ball rebounding, with the net effect being forward. A cotton ball definitely "compresses" though, as would foam and some other materials. Golf balls don't compress much - they don't get denser (by occupying less space while having the same mass) - but they deform quite a bit. More deformation ~= higher smash factor.

I was going to use a marshmallow instead of the lime.

post #6 of 22
Thread Starter 
Quote:
Originally Posted by boogielicious View Post
 

I was going to use a marshmallow instead of the lime.

 

I can get behind the marshmallow. :)

post #7 of 22

My club had a long drive contest with marshmallows once. I'm pretty sure those marshmallows ended up compressed and deformed. I actually tried to pre-compress my marshmallow (figuring I could impart more energy to a more solid target and that a smaller marshmallow would be more aerodynamic). Alas, it did not have the desired effect. In the end, a guy using driver won, but just narrowly over a guy who used an 8-iron. Turns out, the contest was dictated almost as much by wind as anything else, but I'm off-topic. 

post #8 of 22
Thread Starter 
Quote:
Originally Posted by georgep View Post
 

Turns out, the contest was dictated almost as much by wind as anything else, but I'm off-topic. 

 

That sounds like a fun contest, though, so I'm glad this thread drew that out of you. :-)

post #9 of 22
Would the "Compression" number relate to how much a ball "deforms"? With the new balls that are rated at around 60-70 "compression" ratio and the older Titleists being either 90 or 100, there would seem to be more deformation now than in the past. The older balls were meant to be SMASHED with a hard solid face (persimmon, for example), while the newer balls needing to hit with a clubface that has a lot more "give" in them.
post #10 of 22
Thread Starter 
Quote:
Originally Posted by RayG View Post

Would the "Compression" number relate to how much a ball "deforms"? With the new balls that are rated at around 60-70 "compression" ratio and the older Titleists being either 90 or 100, there would seem to be more deformation now than in the past. The older balls were meant to be SMASHED with a hard solid face (persimmon, for example), while the newer balls needing to hit with a clubface that has a lot more "give" in them.

 

Yeah, the ball industry somewhat mis-used the term as well. Though, in their defense, I think balata balls with wound rubber and liquid cores did "compress" a bit more than current balls. :)

 

Note that you can't really find the "compression ratings" for balls very easily these days. They're moving away from that term and that way of thinking.

post #11 of 22
Deformation you could at least observe on high speed cameras, but compression can you even accurately measure in a golf ball?
post #12 of 22
Quote:
Originally Posted by jclark View Post

Deformation you could at least observe on high speed cameras, but compression can you even accurately measure in a golf ball?

I can't imagine how you'd do that... You would need to be able to measure the volume of the ball at impact.
post #13 of 22
Thread Starter 
Quote:
Originally Posted by colin007 View Post

I can't imagine how you'd do that... You would need to be able to measure the volume of the ball at impact.

 

I'm sure that knowing the composition of the materials you could model it and figure out how much urethane or the rubber cores actually compress when hit with a 6-iron.

 

Kind of off topic though. But it has been since the second post, I guess… The post is not about the word compression. It's about how we use words, and why they're important.

post #14 of 22
Quote:
Originally Posted by iacas View Post

I'm sure that knowing the composition of the materials you could model it and figure out how much urethane or the rubber cores actually compress when hit with a 6-iron.

Kind of off topic though. But it has been since the second post, I guess… The post is not about the word compression. It's about how we use words, and why they're important.

Ok, back on topic...

TRAP-DRAW!!! POW!!
post #15 of 22

Interesting. I remember watching a video on Titleist's website about the moment of impact, and how the club face deforms the ball.

 

Check it out here, its pretty neat!

 

http://www.titleist.com/teamtitleist/b/tourblog/archive/2013/10/24/video-the-moment-of-impact-an-inside-look-at-titleist-golf-ball-r-and-d.aspx

post #16 of 22
Quote:
Originally Posted by Motley01 View Post
 

Interesting. I remember watching a video on Titleist's website about the moment of impact, and how the club face deforms the ball.

 

Check it out here, its pretty neat!

 

http://www.titleist.com/teamtitleist/b/tourblog/archive/2013/10/24/video-the-moment-of-impact-an-inside-look-at-titleist-golf-ball-r-and-d.aspx

 

I like his comment that they do all kinds of "sciencey" stuff with the camera as well.

 

"Elastic Deformation" is longer sounding than "Compression", but it could be shortened to "E.D."?

post #17 of 22
Quote:
Originally Posted by colin007 View Post


Ok, back on topic...

TRAP-DRAW!!! POW!!

I heard Johnny Miller say that during a recent tournament.  WTF does it really mean Johnny!

 

Quote:
Originally Posted by Lihu View Post
 

 

I like his comment that they do all kinds of "sciencey" stuff with the camera as well.

 

"Elastic Deformation" is longer sounding than "Compression", but it could be shortened to "E.D."?

I can just see the commercials now, two golfers, sitting in bath tubs on the first tee.

post #18 of 22
JM trap draw I guess in that nanosecond of impact he feels the face press ball into ground which then propels it extra fast towards hole. His way of saying really good shot? He says it so many times I don't even pay attention anymore.
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