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Thread: Indoor Green Speed & Air ,Temperature

  1. #11
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    I must admit that I find that hard to believe, both in theory, or based on that article in which it says:

    "By the time they had completed the task, the surface was running 0.3 of a second faster (17.9 seconds) over its 27 metres curved path. It may not sound much but is equivalent to the bowl rolling 1.37 metres further, compared to a bowl delivered with identical momentum."

    Clearly, if you keep all else the same and vary the weight of the bowl, then the momentum with which it leaves the chute must change - as momentum is generally accepted as mass x velocity; equally if you keep the weight the same, ie the same momentum, but vary the arc (distance actually travelled) then it should take longer to travel the same distance, if the distance is straight-line.

    I do however note in that comment that they say : " 27 meters curved path " - if they are meaning the length of the arc, and not the straight-line distance between end of chute and the jack as I understood you to mean when this was discussed elsewhere, then things are likely to differ.

    The firm in the article is said to use the same bowl on all carpets they test to effect their measurements - there must be a reason for that. If you are right, John, then any bowl would surely do! That alone speaks volumes to me.

    I think the issue here may be that you, John, do not use a chute and however minor/imperceptible the difference in momentum generated by your arm may be, that is confusing things. ie you may be unconsciously compensating for a weight/arc difference to prodice the same desired result. Again, as the article points out, a semingly minor difference in the green's speed has a significant difference on the result - I would think that physics would equally dictate that a difference in momentum will also makes the result differ.

    In any experiment of this nature, if you change a single variable, keeping everything else exactly the same, you should expect a different result.

    Think of the old adage to baffle your young kids with: which falls faster, a ton of metal or a ton of feathers? Then ask if the answer would be different for a ton of metal and a single feather. In a vaccuum they may fall at the same rate, but in the air we operate its a slightly different thing.

    If I had a testing shute, and was a member at an indoor club, I would happily try it out with different bowls! Sadly, I don't, am not and so can't, and I wouldn't trust my arm to generate exactly the same speed of delivery each time - which is why experts use a shute to obtain consistency and the same must apply for the bowl used.

    All the above is based on my memory of science from long ago, and obtained at a low level, as I gave up science at O-level, although I did keep studying maths. Does anyone else have any more recent or higher-level knowledge that could confirm/explain things?

  2. #12
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    Quote Originally Posted by corptaxman View Post
    I must admit that I find that hard to believe, both in theory, or based on that article in which it says:

    "By the time they had completed the task, the surface was running 0.3 of a second faster (17.9 seconds) over its 27 metres curved path. It may not sound much but is equivalent to the bowl rolling 1.37 metres further, compared to a bowl delivered with identical momentum."

    Clearly, if you keep all else the same and vary the weight of the bowl, then the momentum with which it leaves the chute must change - as momentum is generally accepted as mass x velocity; equally if you keep the weight the same, ie the same momentum, but vary the arc (distance actually travelled) then it should take longer to travel the same distance, if the distance is straight-line.

    I do however note in that comment that they say : " 27 meters curved path " - if they are meaning the length of the arc, and not the straight-line distance between end of chute and the jack as I understood you to mean when this was discussed elsewhere, then things are likely to differ.

    The firm in the article is said to use the same bowl on all carpets they test to effect their measurements - there must be a reason for that. If you are right, John, then any bowl would surely do! That alone speaks volumes to me.

    I think the issue here may be that you, John, do not use a chute and however minor/imperceptible the difference in momentum generated by your arm may be, that is confusing things. ie you may be unconsciously compensating for a weight/arc difference to prodice the same desired result. Again, as the article points out, a semingly minor difference in the green's speed has a significant difference on the result - I would think that physics would equally dictate that a difference in momentum will also makes the result differ.

    In any experiment of this nature, if you change a single variable, keeping everything else exactly the same, you should expect a different result.

    Think of the old adage to baffle your young kids with: which falls faster, a ton of metal or a ton of feathers? Then ask if the answer would be different for a ton of metal and a single feather. In a vaccuum they may fall at the same rate, but in the air we operate its a slightly different thing.

    If I had a testing shute, and was a member at an indoor club, I would happily try it out with different bowls! Sadly, I don't, am not and so can't, and I wouldn't trust my arm to generate exactly the same speed of delivery each time - which is why experts use a shute to obtain consistency and the same must apply for the bowl used.

    All the above is based on my memory of science from long ago, and obtained at a low level, as I gave up science at O-level, although I did keep studying maths. Does anyone else have any more recent or higher-level knowledge that could confirm/explain things?
    I never said i used a chute,as the speed was tested by Dales who come to stretch our indoor carpet,i think you are all making a meal of things,C25 in the law book defines the pace of the green,if i go to a club and they tell me there carpet runs at 17secs i can equate that to my own green running at 19.When didi say i would trust my arm to generate exactly the same speed of delivery every time.
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  3. #13
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    "I never said I used a chute" - no, you've said that before and as I said in my last post " issue here may be that you, John, do not use a chute"

    "
    When did I say I would trust my arm to generate exactly the same speed of delivery every time" - you haven't said that, but the implication is that you must, or, as I understand matters, a difference in delivery speed will affect matters as momentum = mass x ... (wait for it) .... velocity! So, if you can;t generate the same delivery speed, like I wouldn't expect to, how can you exect to get a consistent green reading from it?

    This, however, is all nit-picking .You are entitled to go with your views John, and I'm not denying they may be accurate/close to it - all I am saying is that...well, I've said it, so will leave it at that. Let others make up their own minds on the matter.

    C25 - yes, I see that, and it implies a straight line distance of 27m. I'm only pointing out that is at odds with what the article seems to say ("27m curved path" - or am I reading that phrase incorrectly?). C25 does not however ensure that all variables in the test are to be the same so as to give consistency. Fin.




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    Quote Originally Posted by corptaxman View Post
    "I never said I used a chute" - no, you've said that before and as I said in my last post " issue here may be that you, John, do not use a chute"

    "
    When did I say I would trust my arm to generate exactly the same speed of delivery every time" - you haven't said that, but the implication is that you must, or, as I understand matters, a difference in delivery speed will affect matters as momentum = mass x ... (wait for it) .... velocity! So, if you can;t generate the same delivery speed, like I wouldn't expect to, how can you exect to get a consistent green reading from it?

    This, however, is all nit-picking .You are entitled to go with your views John, and I'm not denying they may be accurate/close to it - all I am saying is that...well, I've said it, so will leave it at that. Let others make up their own minds on the matter.

    C25 - yes, I see that, and it implies a straight line distance of 27m. I'm only pointing out that is at odds with what the article seems to say ("27m curved path" - or am I reading that phrase incorrectly?). C25 does not however ensure that all variables in the test are to be the same so as to give consistency. Fin.


    I am concerned thatyou think there are bowls that run in a straight line over 27.metres, but then you do not play indoor bowls do you. The test is carried out over a distance of 27 metres measured from point of delivery to a point 27 metres in line with the delivery point Pace of green is also calculable with a timed delivery over any measured distance
    Last edited by john haydock; 31-01-2019 at 08:45 PM.
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  5. #15
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    "but then you do not play indoor bowls do you" - Whether that be question or statement, I can safely say: the score is up to twice now! Plenty to have grasped a thing or two, if little else, so, thank you for your concerns, but they are quite unfounded.

    We are not going to agree on this, John, so there is little point in either of us keeping on making the same points in different guises. I'm happy holding my own, and to let others decide as they will.

    Just for my continuing education, 'though - presumably Dales used a chute at your green, but what bowl did they use in their tests?

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    My last word,bias of the bowl is mostly irrelevant in calculating green speed,(Rob Judson)
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    I think what this shows is that the 'test' isn't scientific at all. However, if it's done consistently (same chute, same bowl, same calculation) then it gives some level of guidance. Different chute/bowl size/weight/bias then it's next to useless and becomes an extremely 'loose' test with almost no meaning.

    Corp, I think you're trying to use science in a test that simply has no scientific basis as discussed in another thread. What comes into question is the difference in distance 1 sec of (flawed) test makes? They say 0.3 of a sec makes over a metre of distance. How is that calculation made? That's where a non-scientific test really gets into trouble.

    It's really there just to give an overall guide, nothing more or less. The reality and important thing is, you turn up, roll a few bowls down and make an adjustment (or not). The human 'feel' is effected by thousands of inputs like perspective, activity in the last 30 mins before playing, temperature, clothing, mood etc etc. You end up having to play what's in front of you. Most players only use it as an excuse for playing badly. The green is fast/slow, holds out, doesn't finish and any other reason you can think. Ask another player who has won and played well and you'll get a totally different answer.

    I've also heard speculation at my club that cold makes the carpet slower. However, to me, that would seem to defy science and I'm glad to see Dales in that article also say they would expect it to be quicker.

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    Thank you to all those who replied to my question. Some of you appear to have incorrectly picked up on how different biased bowls perform. The question was not about different biased bowls, but whether the carpet at the club where I bowl was affected by temperature. There appears to be a difference when bowling in the morning then the evening. I thought that warm conditions would be faster and cooler conditions slower, but my experience, and some of my fellow bowlers, find the opposite. Hence my question. I realise that the bottom line for all of us is that we have to adjust on the day, at what ever time, on the different rinks. I was asking for bowlers' experiences, if they had any. Thanks again everyone.

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    Can anybody please tell me how a artificial out door green compares to an indoor carpet regards speed and line of a bowl

  10. #20
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    Default Speed of green


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    Quote Originally Posted by lefthander View Post
    Can anybody please tell me how a artificial out door green compares to an indoor carpet regards speed and line of a bowl
    The simple answer is NO,all greens vary as to speed,there are several factors, type of underlay etc. There are many outdoor synthetic greens all of a different speed,as a general rule the indoor carpets run quicker.the quicker the green the more bias your bowl will take, that applies on any carpet
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