|MadSci Network: Physics|
Interesting question. I suspect it is going to be extremely difficult to measure appreciable differences between verious metal clubs. Typical differences between a steel or titanium iron (the golf club) is going to be very small compared to the variation in a golfers ability to reproduce the same swing. I recommend you look at measure the difference between a metal wood and a wooden wood :) BACKGROUND: Metal has many advantages over wood in both golf and baseball. The advantage comes down to two principle effects: 1) A bigger sweet spot and better response away from hitting on the sweet spot. 2) less loss of energy at impact. The sweet spot of a club or bat is the region that gives the "truest" hit of the ball. For a wood bat this region is about 2 or 3 inches long and about 2 to 4 inches from the barrel end of the bat. For a wood golf club the sweet is typically about a 1 inch and for a titatium club the sweet spot can be almost as big as the entire hitting surface. But the big advantage is what happens on an impact away from the sweet spot. In Major League Baseball (played with wood bats) it is typical for a bat to break on contact with an inside pitch. In college baseball, the third baseman will get his head taken off by a well struck inside pitch to a right handed batter. In golf, the better impact away from the sweet spot allows the golfer to have slight variance in the striking position along the club face and still produce decent distance (although direction may suffer greatly). Perhaps, obviously if less energy is lost at impact with the ball, more energy is availble for kinetic energy of the ball. More kinetic energy typically means more distance. Finally, some other advantages are possible with metal golf clubs. The Golf clubs have grooves in the face to improve impact with the ball by allow for more spring the clubface and preventing the ball from slipping too much during impact. grooves in the club can be made with flat channels which for reasons not fully understood (at least by me) causes more energy to be transferred to the ball than the tradtition grooving. Metal clubs can more easily have the weight changed without adversely affecting performance. A lighter club can be swung faster, generating more kinetic energy. If all other properties of the club's impact ability stay the same, more kinetic energy of the club will mean more kinetic energy to the ball. HYPOTHESIS: Metal woods give the golfer more distance than wooden woods. EXPERIMENT: Gather a few volunteers of some golf ability and have them hit balls with a wooden and metal driver. I would do this first and then go back and try metal to metal comparisons if the wood to metal comparison gives strong results. Try to get the clubs to be as close to the same in "feel" as possible. Have the golfer take a few whacks with one club and then switch to the other. For example, hit 5 balls with club A and then 5 with club B, and then do it again for say 5 or 6 alternations. That way you will get 25 or 30 measures of distance with each club. Then do this with several golfers. After you have done this with a handful of golfers. You can see if there is a statistically significant difference in the distances. For each golfer, compute the mean distance and the standard deviation for each club and report the result as mean +/- std. deviation. You will get a table that looks something like this ( I will explain the commments below): club A club B comment (distance yds) (distance yds) golfer 1 210 +/- 30 220 +/- 10 not different enough golfer 2 250 +/- 20 210 +/- 25 maybe A is better . . . golfer N 230 +/- 10 190 +/- 15 club A is better A simple way to decide if the difference is significant is to see if the difference of the means is bigger than the sum of the standard deviations (there are other ways but this is easiest). absolute diff Sum of means sum of std dev.'s comment golfer 1 220 - 210 = 10 yds 10 + 30 = 40 yds diff mean < sum std dev golfer 2 250 - 210 = 40 yds 20 + 25 = 45 yds close but diff mean < . . . golfer N 230 - 190 = 40 yds 10 + 15 = 25 yds diff mean > sum std dev Notice that the pretend measured results even have a case where club B averages a longer distance than club A and 2 cases where club A averages a longer distance than club B. This will likely happen in the experiment. Real life golf club manufacturing companies try this sort of thing with machines but still always get professionals and common folks to try it too. CONCLUSIONS: Have fun trying it out. I hope this helps you create an even better experiment. It all depends on your patience. And don't forget to look the statistics with the same club but different clubs (i.e. if you take all the hits with club A versus all the hits with club B, what do you get?). Sincerely, Tom "Golf Hacker" Cull
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