Ball Bearing Experiment
Ball Bearing ExperimentI dropped a 2" ball-bearing off a 400' tower and timed it. It turns out it was accelerating at about 32 feet per second per second. I tried it on a 600' tower and it worked the same way. I also did it with a 4" ball bearing. Same way.
I have no reason to believe it would work with a bowling ball. -- RonJeffries
On this page, the number 32 ft per second per second is referred to more than once. Those of us who use proper measurement call that 10 m.s^-2 (10 metres per second per second). Anyone heard of the SI? Some people are very much attached to the OldUnits. The ball bearing is accelerating at the same rate - the units used to measure it are relevant only for our discussions. Why trash someone for their choice of units when it has a valid reason?
Suppose you have a system with a monkey typing randomly into a keyboard. And you are observing what gets written to the screen.
At some point, you realize that there have been 18 trillion digits typed to the screen and all of them (except the first 184) have been "1".
There is a strong argument that all the rest of the digits (for all eternity) will be "1" as well. The intuition is, roughly, that the overwhelmingly most likely explanation is that the monkey managed to enter an encoding of the program "while (true) print 1" (why a program? Otherwise 18 trillion consecutive 1's is extremely unlikely. Why an infinite loop? Otherwise the monkey had to encode the length of the loop and longer length encodings are less likely. The more "1"'s get printed to the screen, the more likely it is that the monkey encoded an infinite loop).
As with monkeys, so too with the universe. The more data you get about balls of various sizes, the more likely it is that balls of other sizes will behave the same way.
The argument, in a slightly different form, was originally due to Laplace. But I think it's charming.
There is probably a deep connection to the inability to predict 1/f type distributions here, but I'm too lazy to make it at the moment.
Now apply this to the limitations of XP ...
I'd prefer to apply it to the following statement:
Every methodology which I have ever run across has turned out to be profoundly limited and, while well-suited for some tasks, incapable of capturing the nuances of good practice across a wide range of projects.
Laplace then justifies :The more methodologies I run across, the more skeptical I become of the remainder. As a curious aside, it also seems that the more methodologies I run across, the more there are out there (and Laplace supports the implication that, somehow, when I observe a methodology, other methodologies spring into being).
As a CardCarryingMethodologist?, I agree with WilliamGrosso. Anyone who challenges me that my methodology is wrong has history on their side. As it turns out, I have never met a trustworthy documented methodology either - including my own, which is why these days I am trying to document them with slack in them for people to adjust (and which will backfire and fail in its own way). Now, watching the group at C3 work, they followed their declared methodology closer than any other group I have seen, and with excellent results.
Now what all this has to do will ball-bearings and bowling bowls, I am not sure. Except that it is a cognitive "thing" about us western people that we generalize from a single sample point, declare rules or irrefutable rules from two. So of course after dropping a ball bearing from 400' we say, "Ah, 32 ft/sec2 is the rule"... after 600' we say, "See I told you it is 32 ft/sec2 - and of course it also applies to feathers - try it any time you like, I'm out of here." -- AlistairCockburn
I told that fellow who subsequently left that the towers have to be in giant bell jars with all the air sucked out. Here's the spec. That'll be an additional $20,000 please. -- rj
The thing that astonished me when I saw the astronauts drop the feather and the ball on the moon was not how slowly the ball fell in 1/6 gravity (I didn't notice any speed difference visually), but how fast the feather fell without air resistance (it fell like a lead balloon, oddly enough). -- AlistairCockburn
I find this discussion of feathers in airless freefall deeply troubling. -- MichaelFeathers
(hee-hee, that was so good, I read it to my kids this morning. One of them generated the additional experiment. Cameron is 10 years old, Kieran is 5. We decided I would test all the above: I would climb our tree, and hold Cameron and Kieran by their feet, drop them, and see whose head would hit the ground first. Sean, age 8, was the one who identified the trick: Observing that Cameron's head hit the ground first, we would derive that heavier things fall faster than light things! (he also gave the correct answer w.r.t. height) -- AlistairCockburn)
I'm searching for my lost link to BellsInequality. I thought I saw it on Wiki. I'm trying to show that deductive logic may be false. You see, I'm writing an essay on skepticism in the true philosophical sense of the word, so this page is rather funny for me. (perhaps I should be writing my response in my essay, not here) I would point out that you don't even know if there really is such a thing as gravity because you have to trust your senses to tell you as such, and senses tend to lie. So we can't know anything. Time to pack up shop and head for the beach then ... it's all a show between my ears anyway.
By the way, what happens when you tie a feather to a bowling ball and throw the package off the tower? Surely the feather still wants to fall slower than the bowling ball, and the bowling ball wants to fall faster than the feather, so the speed must average out in between, right? But a bowling ball + a feather weighs more than a bowling ball by itself, so they should fall faster than a bowling ball. Oh, I'm so confused. Gallileo knows more than I do anyway. Go ask him. -- SunirShah
In a perfect vacuum, it shouldn't matter. However, since we don't have any towers in vacuum anywhere on this world that I know of, it all comes down to the drag exerted on the package by the surrounding air. Chances are, the differences in drag are negligible. Which reminds me, I got this parachute here, which I tie to the bowlingball. Now that sure is a heavier package than just a bowlingball by itself... I know, it's a drag.
[A communications satellite in geostationary orbit is in a nearly perfect vacuum, so let's calculate its acceleration towards the earth...]
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