Creative Speculation
In reply to the discussion: What a Gravity Driven Demolition Looks Like by David Chandler - sottotitolato in italiano [View all]William Seger
(11,346 posts)Last edited Mon Nov 9, 2015, 01:02 PM - Edit history (1)
Chandler claims that it's been "proved" that "the top section of the north tower of the WTC could not have crushed the lower section of the building." His own "proof" is an analysis which completely ignores dynamic forces, which is a mistake worth about two orders of magnitude. He plots points 0.2 seconds apart from a grainy video, draws a line through them, and declares that his own straight line means the top fell at "constant acceleration," ignoring whatever might be going on between the points. But to make things worse, Chandler claims that the constant acceleration he thinks he measured must be the result of destroying about 90% of the columns. That's an argument which simply demonstrates Chandler's ignorance of structural mechanics and failure modes, in which the resistance would be anything but constant as the top descended, whether it was all the columns or only a few. Chandler has yet to show how any type of collapse, even with magical silent explosives, could possibly produce the constant acceleration he claims. Now, since more careful measurements show that it isn't actually constant, that's a mystery Chandler really needn't solve, but he should at least try if he's going to keep making the same fallacious argument.
Next, Chandler says "the other side of the same coin" is Szamboti's "missing jolt" hypothesis which he claims is another proof because not seeing deceleration "jolts" in videos means there weren't any impacts. That's just a false claim for two reasons: first, small jolts are seen when Szamboti's own data are analyzed properly; and second, if gravity is continuing to accelerate the mass, then impacts don't necessarily produce deceleration. The small jolts that are seen are not of the magnitude Szamboti expected because his first premise is wrong: the top of the building did not fall squarely onto the bottom, allowing all the columns to simultaneously react with their maximum resistance to buckling. The collapse started on one side and progressed horizontally, which produced a tilt and a series of individual failure events spread out over time, with virtually no column-on-column collisions. Examination of the debris shows that most of the destruction was due to ripping the floor structures away from the columns, and with that loss of lateral restraint, most of the columns were pushed aside or buckled and broken at their splices. That required much less force than crushing the columns, which is why it happened first, and in individual failure events where the required force was less than that required to completely counteract the continued gravitational acceleration of the impacting mass, there would be no actual deceleration -- no "jolt" -- just reduced acceleration. Chandler and Szamboti both completely ignore the fact that when they measure the fall of the roof-line, they are really just measuring the averaged effects of thousands of individual failures spread out over time. And, like Chandler, Szamboti does not actually produce any rational controlled demolition hypothesis that actually explains what we see; he just assumes that it's somehow a better explanation.
"To check why this analysis is correct" Chandler then shows a video of a Verinage demolition where the top of a building does indeed fall squarely on the bottom, which explains why the "jolts" are more noticeable. Although it was actually a building with load-bearing walls instead of columns, as Chandler mistakenly assumes, what Verinage demolitions really prove is that if the top of a conventionally designed building falls onto the bottom, there is more than enough gravitational energy to destroy the building, with no need for additional energy from explosives.
As an aside, Chandler then goes on to claim that the Verinage video also shows that the top and bottom sections are destroyed "at the same time" and this "is a clear consequence of Newton's third law, which says that when bodies interact, the forces act equally in both directions." What this really shows is that knowing Newton's laws and applying them correctly in a given situation are two different things, even if you're a high school physics teacher. Chandler completely ignores that the "bodies" that interact in the destruction of the top section are the top interacting with everything below, and the force is due to the mass and momentum of just the top, whereas the destruction of the bottom section involves the interaction of the bottom with everything falling, and the force is due to the mass of the top section plus a debris layer that's increasing as the collapse proceeds. With that understanding, one should not be surprised that in videos of Verinage demolitions where the collapse front can be more clearly seen, the bottom section is in fact destroyed more rapidly than the top. What we really see here is Chandler's "confirmation bias" at work following an analysis model that is simply and obviously wrong. But it gets much worse when Chandler tries to explain why this is supposed to matter: he makes the completely stupid claim that "at most, the top 12 floors might have destroyed an additional 12 floors, but the top section would have been consumed in the process, leaving nothing to crush the rest of the building." In other words, in this physics teacher's world of imaginary physics, the mass and momentum of the debris from those 24 floors would just disappear into an alternate universe because it has somehow been "consumed" by the impacts. Chandler seems to think this ridiculous argument is an additional "proof" against a gravitational collapse, but in fact it raises serious questions about what other kinds of nonsense he might be teaching his students.
Given that there is no need for explosives to explain what we really see and also no evidence of explosives, either, there is no real use for any explosive demolition hypothesis, especially one that requires magical silent explosives yet still doesn't really explain what we see. Like the Harrit "nonothermite" paint chips, there is exactly zero chance that either Chandler's or Szamboti's arguments would ever be published in a real peer-reviewed technical journal, because they are abject bullshit. And make no mistake about it: this is as good as it gets with "truther science."
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