I have seen no evidence that the buildings fell down. I began by stating that it appears to me that some very large percentage of the non-metallic mass of the twin towers was rendered into fine powder. Though JREF's have had no shortage of statements to the contrary, I have seen no evidence to the contrary. You have shown me pictures accounting for, at most, 1/10th of 1% of the concrete.
So, pictures are the only evidence you will accept? And why exactly do you think anyone would have taken such pictures of the rubble? Why would anyone on the day have expected they would need to address such questions years after the fact?
As far as "similar pieces of debris", I'm looking for acre-sized slabs, with a rectangular hole, like giant square donuts, 220 of them. Thus far I have found zero.
And what leads you to expect "acre-sized" slabs? You claim to be such fan of physics, please explain how an acre-sized slab of concrete can fall any distance and not shatter into smaller pieces. Have you ever worked with concrete paving stones? They're brittle. They break when they fall. Any major project that uses them expects a certain amount of loss due to such breakage. Please explain how your expectation is in any way reasonable.
When the event is over, we observe shredded steel strewn about upon a vast field of dust. JREF members have shown pictures of rescue efforts and such that show pieces of concrete that escaped disintegration. My generous estimates are that these pictures show 200 tons, total. Tops. That would be 1/10th of 1%, using the figure 200,000 tons of concrete.
So, these 1/10th of 1% numbers you keep tossing off are "generous estimates". Please explain how you made these estimates, beyond just looking at a few pictures. Again, anyone who has worked with concrete will tell you, it produces way more dust than you would expect. I've shown my calculations about the dust on at least
two occasions. If you've really done any serious attempts at estimating how much dust there was on the day, please show me, with numbers, where you think my analysis went wrong. As I said in the previous threads, I figure about 3.5%-7.6% of the original mass turned to dust.
Please don't just ignore this again. You claim to be a fan of science, try doing some. Address my analysis, and perhaps we can both learn something new. I already know what pictures you've looked at, so don't bother posting those again. Show us some real work.
So here is the hierarchy. Gravity collapse (least disintegration) > standard controlled demolition (some disintegration) > twin towers (near total disintegration)
Take a look at this:
http://youtube.com/watch?v=6yK9XLRb1u8
Demolition of the Landmark Tower in Forth Worth, Texas, which left this as a debris pile:
http://www.flickr.com/photos/atomicglee/115419262/in/set-72057594084335155/
So, where in this debris pile do we see "slabs" of concrete? Why don't we? What force "disintegrated" them in this case?
And while we're at it, where did all the dust come from in the video?
And I think that's enough for now.