Quote from Maverick1:
FACT: Once each tower began to collapse, the weight of all the floors above the collapsed zone bore down with pulverizing force on the highest intact floor. Unable to absorb the massive energy, that floor would fail, transmitting the forces to the floor below, allowing the collapse to progress downward through the building in a chain reaction. Engineers call the process "pancaking," and it does not require an explosion to begin, according to David Biggs, a structural engineer at Ryan-Biggs Associates and a member of the American Society of Civil Engineers (ASCE) team that worked on the FEMA report.
Like all office buildings, the WTC towers contained a huge volume of air. As they pancaked, all that air--along with the concrete and other debris pulverized by the force of the collapse--was ejected with enormous energy. "When you have a significant portion of a floor collapsing, it's going to shoot air and concrete dust out the window," NIST lead investigator Shyam Sunder tells PM. Those clouds of dust may create the impression of a controlled demolition, Sunder adds, "but it is the floor pancaking that leads to that perception."
My thoughts:
I don't buy the above government backed 'debunking' because it sounds like a bunch of BS to me on this important issue of the squibs. What shocked me when I saw the close up of the squibs and tower collapsing was that some of the squibs happened on the lower floors WAY before the top which was crashing down caught up to those lower floors. Mr Shyam Sunder sounds like he's completely ignoring that fact when conveniently trying to dismiss a straw man argument, namely that the coincident dust and air shooting out from a floor that is collapsing looks like its caused by an explosion. That is NOT what caught my attention. It is the squibs on the lower floors which did, and I'm afraid that this FEMA led research piece is pure crap.
I'm still waiting for someone, maybe Version 77 to explain to me what those squibs were if they weren't explosions but more importantly why did they happen on the lower floors way before being caught up to by the crashing upper floors.
Here's a possibility:
[0] The collapse begins at the top of the building and proceeds
downwards. It's evident on all videos I've seen. No downward movement
of a lower floor is apparent before the collapse front reaches the level of the floor.
[1] The weight of the collapsing section of the building at the top compresses
air beneath the descending collapse front.
[2] Below the front, compressed air is pushed generally downward and moves in
whatever way possible through the building. Escape is possible
sideways
through the windows, when pressure becomes sufficient to break them, and
downwards through the building itself ... through the ducting system,
elevator shafts, stairwells, etc.
[3] Thus air pressure also begins to build on floors
below the collapse front,
as some fraction of the air from the already collapsed sections flows
downwards into the building. The airflow may cause high winds in lower floors
also.
[4]
Some windows on lower floors, possibly weakened already by the
impact, burst from local overpressure, producing the puffs of dust visible in
some photos.
This is my speculation, based on my knowledge of physics. To back it up would
require a more detailed simulation of the building geometry than I'm willing
to get into. But it seems a plausible explanation, to me. More plausible than
the suggestion that explosive `squibs' went off on lower floors as part of a
`controlled demolition,' but that the lower floors did not start to move
before the collapse front reached them.
Also, why such an abundance of testimony referring to multiple explosions
happening before and after the planes crashed into the planes? Are they also
lying for the fun of it???
That's a strawman: there's no need to say they were lying. Maybe they heard
something, or thought they heard something. This doesn't mean there were
explosions.
Primary evidence of explosions consists of traces of explosive materials.
Such evidence appears to be absent.
Anyone want to show how smart he is? There seems to be a lot of experts here
on the governments side.
I'm not all that smart, and beyond having a degree in physics, I'm not an
expert at all. I'm not on the `government's side.' I'm simply extremely
unimpressed by the quality of the arguments by the conspiracy theorists, as
well as their selective use of evidence.
For example, pictures are repeatedly shown of the relatively undamaged
North side of WT7 during its later collapse, while pictures of the extensively damaged
South side are either ignored, or argued to be fabrications.
Extraordinary claims require extraordinary evidence.