Reply #260: Wonderful, wonderful stuff

[TrogL]

for proving my point. Thank you.

When they demolish a building, they try to make the entire thing come down at once. Somewhere up above is a link to a site showing exactly that. I'm sure you've watched documentary shows on TV about building demolitions.

That's not what we're seeing.

When they set off the shaped charges to blow out the supports (after laboriously weakening them with saws - a week's long process) they display a sharp-white actinic light, almost like looking at a welding torch or an arc lamp. It displays in all the windows simultaneously.

Compare this with the slow-rolling billow of a gasoline explosion. You've seen plenty of these. In the movies, when stunt people do explosions with dynamite, they don't use dynamite. It looks crappy and unexciting. To boost the action, they use gasoline. It makes a big, messy fireball. Remember the footage of the bomb at Olympic Park? You could barely see it - it was just a bunch of sparks. That was a dynamite bomb.

What all those nice pictures are showing us is a perfect example of ordinary fire being squished out of a burning building by pancaking floors.

There's no "hot gases" with a dynamite explosion - it's a waste of energy. The purpose of a dynamite explosion is the shock wave. You don't get a good shock wave from a gassy explosion like gasoline.

As to all that nonsense about the smoke preceding the collapse? It's basic hydraulics. The other day, I bought new air mattresses for the kids and spent the next two hours pumping them up. I would pump and pump and blow and blow and send a tremendous amount of air into the mattress and it just sat there limp, gradually raising itself a few millimetres at a time. That building is wide. A small drop in the ceiling would be a large surface area compared to the width and height of the windows, hence it would force tremendous amounts of air out, pushing the smoke and flame along with it. It's basic physics.

Why didn't it happen on every floor? Because it wasn't a controlled explosion - otherwise it would have been every floor.

He makes a big point about the dust at the bottom below the fire being white and the "dust" above the fire being grey. Do I really need to point out that dust (probably mixed with broken glass) is white (or thereabouts) and smoke is grey??

Ok, now for the antenna. The antenna is attached to the concrete core. The floors are collapsing first. Of course the antenna doesn't move. It doesn't move until the weight of the trash from several collapsing floors weakens the integrity of the central concrete core, which breaks off and blummets down, smashing the remainder of the concrete core and the floors. You can see it in the pictures. Thank you for linking to them.

Finally, he invokes Occam's Razor (incorrectly) saying that planned explosions is the simplest explanation. This involves a conspiracy of thousands occuring directly under the eye of thousands of others with perfect coordination of thousands of chaotic events like explosions and wind currents. There's a much simpler explanation.

Planes go crash.
Fuel goes whoosh.
Fires goes sizzle.
Building fall down and go boom.