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Post by theteacher on Apr 14, 2011 18:59:40 GMT -4
Though these ideas are part of modern science, I don't think they are necessary to science as such. A lot of science does not at all include these ideas, and it is not necessary to include an axiom, that the laws of nature are the same on for instance the Moon as on Earth. That is based on - and is subject to - experience. I beg to differ. I think the axiom that the laws of nature are universal and unchanging is pretty basic to all of science. I would prefer to say, that that understanding has become pretty basic over time. I'll bet that the considerations of G. S. Ohm, when he discovered the numerical connection between voltage, current and resistance an formulated what we today know as Ohm's law, did not include, if that law obeyed an axiom of universality. I might lose of course though, if you can prove otherwise, but I don't think so. Absolutely. But how did the idea, that physical laws are the same everywhere, come into the heads of scientists and philosophers? No, not philosophers. Take Aristotle who didn't perform experiments. He claimed that the heavier the body, the faster it would fall. I mean if the physical laws were changing with time and place, it would be discovered by the experiments. So the notion that they don't, is a result of empiric experience with repeating experiments all over the world, and on the basis of the results it seems to be a reliable fact, that the laws are universal. So again it is a fundamental in science, but it didn't arrive in our heads out of the blue.
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Al Johnston
"Cheer up!" they said, "It could be worse!" So I did, and it was.
Posts: 1,453
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Post by Al Johnston on Apr 15, 2011 6:06:12 GMT -4
I think Galileo may have been one of the first to articulate it.
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Post by Glom on Apr 15, 2011 7:58:03 GMT -4
A heavier object will fall faster because it the air resistance will make proportionally less impact on its acceleration due to gravity. Aristotle may have been possessed of a certain intuitive impericism.
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Bob B.
Bob the Excel Guru?
Posts: 3,072
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Post by Bob B. on Apr 15, 2011 8:27:22 GMT -4
A heavier object will fall faster because it the air resistance will make proportionally less impact on its acceleration due to gravity. Technically that is not entirely true, though I understand what you mean. The object with the greatest ballistic coefficient will fall fastest. In most cases, the more dense object will have the greatest ballistic coefficient, which isn't necessarily the one with the most mass. For instance, a basketball may weight more than a small rock, but the rock likely will have the greater ballistic coefficient. Clearly your comment was in reference to objects with similar dimensions and drag coefficients. In this case, the heavier object will have the high ballistic coefficient and will, consequently, fall faster. Of course this is only true in an atmosphere where the objects are subjected to drag forces. In a vacuum the objects will fall at the same rate regardless of size or mass. Hence the purpose behind Dave Scott's hammer and feather experiment.
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Post by sts60 on Apr 15, 2011 11:35:53 GMT -4
I thought this quote from Lunar Sourcebook: A User's Guide to the Moon was apropos: "By 1989, almost two decades after the first samples were obtained, the Apollo collection was probably the most intensively studied suite of rocks on Earth." Of course no one knows with certainty whether there actually was a year 1989.
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Post by trebor on Apr 15, 2011 11:38:36 GMT -4
I thought this quote from Lunar Sourcebook: A User's Guide to the Moon was apropos: "By 1989, almost two decades after the first samples were obtained, the Apollo collection was probably the most intensively studied suite of rocks on Earth." Of course no one knows with certainty whether there actually was a year 1989. I certainly have no memories of 1989...
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Post by echnaton on Apr 15, 2011 13:10:11 GMT -4
I certainly have no memories of 1989... That was the year I spent on tour with The Rolling Stones, so neither do I.
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Post by torch2k on Apr 15, 2011 14:52:08 GMT -4
Take for instance the gentleman, who made this website: www3.telus.net/summa/moonshot/index.htmWouldn't you say, that he has a true scientific approach to the problems, he is trying to solve? Contrary to him we have the average HB, who won't even go outside and take a photo of the stars just to see, what will happen. Thanks for that link. I can't recall seeing that site before, but it's interesting how easily the author has refuted so much of the 'photographic analysis'. If I was a dyed-in-the-wool HB, though, I imagine it would be problematic. Since photography works the same way in Vancouver as it did for Apollo, is this proof that the Apollo photographs were faked in Vancouver, or that Vancouver is actually on the moon?
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Post by Glom on Apr 15, 2011 14:58:15 GMT -4
A heavier object will fall faster because it the air resistance will make proportionally less impact on its acceleration due to gravity. Technically that is not entirely true, though I understand what you mean. The object with the greatest ballistic coefficient will fall fastest. In most cases, the more dense object will have the greatest ballistic coefficient, which isn't necessarily the one with the most mass. For instance, a basketball may weight more than a small rock, but the rock likely will have the greater ballistic coefficient. Clearly your comment was in reference to objects with similar dimensions and drag coefficients. In this case, the heavier object will have the high ballistic coefficient and will, consequently, fall faster. Of course this is only true in an atmosphere where the objects are subjected to drag forces. In a vacuum the objects will fall at the same rate regardless of size or mass. Hence the purpose behind Dave Scott's hammer and feather experiment. Yes of course. I would thinking of the plastic cube vs the lead cube.
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Post by theteacher on Apr 17, 2011 7:44:35 GMT -4
A heavier object will fall faster because it the air resistance will make proportionally less impact on its acceleration due to gravity. Aristotle may have been possessed of a certain intuitive impericism. Your remark here made me realize, that I just reiterated a rather simplistic view. In Wikipedia it says: "A heavier body falls faster than a lighter one of the same shape in a dense medium like water, and this led Aristotle to speculate that the rate of falling is proportional to the weight and inversely proportional to the density of the medium". See en.wikipedia.org/wiki/Aristotelian_physics#Life_and_death_of_Aristotelian_physicsSo you certainly have a point.
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Post by PeterB on Apr 17, 2011 8:10:55 GMT -4
Okay, let me refute it. 1. NASA has rocks... {big snip} Please show me where my logic is faulty. You really didn't prove anything at all. Boy it's a shame you were banned. I would've loved to have chased you to explain where my logic was faulty...
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