...surely because of the momentum of the collapsing upper floors, together with their mass, which was no longer ultimately transmitted to earth via the few pillars (basically the same principle as flying buttresses, as used on medieval cathedrals). Once one floor collapsed, it's full weight (and that of all the higher floors) was borne by the floor below, rather than by pillars and the outer skin (to a lesser extent). That floor then collapsed too, so that the one beneath it now supported even more weight than that which had just caused the one above to collapse, and so on (?)....

When I try to visualise this 'pancake collapse' type of model, I see several problems with it. Firstly the buildings collapsed in around 12 to 14 seconds (the official report says 10 seconds, others claim as much as 16 seconds) there's a helluva lot of smoke and dust so it's actually difficult to tell precisely. This is surprisingly fast considering freefall in a VACUUM works out at 9.2 seconds! When you factor in air resistance you find a man jumping off the roof of the WTC would take 11 seconds to hit the ground. Now if you try to visualise one floor collapsing on top of another and transferring its momentum and then collapsing onto the next floor and so on 100 or so times - how long does that take in your 'thought video'? - surely considerably longer than freefall time? Someone much smarter than me with a PhD did the maths for two slightly different models and got times of 28 to 88 seconds! But then in addition to that we see from all the concrete dust produces throughout the collapse that the floors were pulverised on their way down. So a considerable amount of the energy of the collapse must have gone into pulverising the concrete and therefore couldn't have been available to transfer momentum to successive floors below, slowing the 'collapse' still further. The numbers don't add up.

regards Derek

A** C****, ... on 10 August 2006 at 19:52 +0000 wrote:
A** C**** writes:
Give us some numbers then. I've supplied some formula.
http://forum.physorg.com/What-was-the-weight-of-a-WTC-Tower_4299.html

...er, sorry A**** I'm still confused about what formulae you're talking about and what numbers you'd like me to provide.

regards D

Dangle Mouse, on 10 August 2006 at 09:39 +0000 wrote:
P***** . B******** on 09 August 2006 at 22:16 +0000 wrote:
That floor then collapsed too, so that the one beneath it now supported even more weight than that which had just caused the one above to collapse, and so on (?)..

Yes, this was the argument used. That heat resisting anti-flame material covering the floor suspension corner 'buttress-joints' (Rather like tiny hammer beam roof supports) had been shaken off during the impact. and from 43 of the 47 gravity load bearing central support pillars in WTC1 according to NISTNCSTAR1, a number of which were also severed - 6 according to NIST [ or 3 in Derek's copy of the report ]That the 800°C temperatures were then sufficient to cause floors suspended on these corner structures to start the pack of cards collapse. This is what we were told officially even by a UK terrestrial TV investigation.

I'd have thought that when the Japanese designers architect [singular - Minoru Yamasaki ] and distinctly non-Japanese sounding engineers - John Skilling and Leslie Robertson who swear to the Emperor that both Twin Towers were designed to survive direct major airline impacts and subsequent fires, not verifiable - there is no documentary evidence of the criteria or methods used to produce the impact analysis upon which this design claim is based - limited technical capability in the 1960s [NISTNCSTAR1 5.3.2] that these LITTLE THINGS would have not gone un-noticed & have been factored in for, before issuing a Titanic like assurance about the supposed survivability of these buildings.

Maybe if the design had used more pillars and not been so open-plan, (which was a major design highlight), the buildings would have survived....

The buildings had massive Central core steel structures, I think using 39 47 giant RSJ beams in a tight central formation, in which the elevators were housed though this was not their primary function of course. If you look at the pictures of these core structures; although I am not, nor have ever aspired to being a civil engineer or architect (I was a lazy child, I suppose) these structures do not suggest a total 'OPEN PLAN' design. The design was an "empty tube" plan. The support columns were in the core and at the perimeter giving the intervening floorspace a column-free open expanse Something approaching 1500 feet, 1368' & 1362' designed to withstand and survive aircraft impacts per-se not verifiably must have some hefty features incorporated.

I do not believe these were Japanese paper constructions. What do you call that art of modelling in paper, Japanese style? origami?

A* C***, ... writes:
When I try to visualise this 'pancake collapse' type of model,
The upper floor (working on 10% of building and a 3m fall) hit the lower part of the building whilst having K.E. of about 1E8 joules according to my rough sums.
Whilst the upper floors were in free flight the load was removed from the lower part. Where does that energy go?
We are talking energies of seismic proportions.
Who needs explosives and what part can they play in accelerating the fall that equates to a 1E8 Joule hammer.
M***

A* C***, ... on 10 August 2006 at 20:00 +0000 wrote:
Mickey M. Mouse, ... writes:
When I try to visualise this 'pancake collapse' type of model,
The upper floor (working on 10% of building and a 3m fall) hit the lower part of the building whilst having K.E. of about 1E8 joules according to my rough sums. I'm confused by your notation here...do you mean 10 to the power 8 Joules?

We are talking energies of seismic proportions. I guess you do.

Energy is a bit messy and flies about in all directions being scalar. I was hoping to simplify things by thinking in terms of momentum. Basically I can't see how a collapse time close to freefall is consistent with the transfer of momentum to 90 successive floors. Let's say floor 100 (of mass m) collapses under gravity. When it contacts floor 99 below (also of mass m) it has momentum P=mv. The combined momentum as floors 100 and 99 start falling together is still P but since the total mass is now 2m their combined velocity must be 0.5v. That is the velocity is half what it would be under freefall. Taking your model where the top 10 floors fall together onto one below the slowing of velocity is not so dramatic but still represents 90% of what it would be under freefall. The pancake collapse model just takes too long. It doesn't make any difference whether the energy is of 'seismic proportions' it can't make things fall faster than g.

regards *******

06 July 2006 17:37:28
Science chat
From: D M. Mo
Subject: Re(6): Scientific Truth
To: Science chat

Jon H writes:
>>Rather than looking at the evidence and coming to a conclusion he's
>started with the conclusion.

On the contrary the evidence Dr Jones has started with is:
1) Prior to WTC no steel-framed building in history had ever collapsed due to fire.
2) The only similar buildings which have ever collapsed did so due to earthquakes, in which case they tend to topple onto their sides retaining their overall box structure.
3) WTC7 was not hit by an aircraft yet collapsed in the same way as WTC1&2.
4) The time it took the buildings to collapse was basically the time of free-fall from the roof.

He started with these facts and then tried to construct a theory that could explain them. The official 911 Report does not.

regards derek

R N. I on 23 August 2006 at 21:01 +0000 wrote:
What the NISTNCSTAR1 report says [p70 of 298 in the PDF] is:"The reader should bear in mind that the described damage to the building exterior was derived from eyewitness and photographic evidence. The described damage to the aircraft and the building interior was deemed most likely from the computer simulations and analysis carried out under the Investigation."

I am downloading the NIST report now, a 50Mb file. I was reading I imagine the same NIST comments last night as you posted the above. Perhaps it's a different version? The one I'm looking at is the 'Draft'. My interpretation of their presentation is that the study done by the NIST was limited in it's investigations to 'building and fire safety' , due to a limited budget.

The quote you have generously given above and the subsequent bulleted section of the named document, if it's the same one, go on to mention that the conclusions they draw, because of the lack of solid evidence to substantiate their experimental conclusions, mean they have to assume that Jet-A fuel from the aircraft was pouring down the escalator shafts and through damaged ceilings. This they say was corroborated by eye-witnesses.
These not totally substantiated claims have to be accepted as gospel for NIST be able to reach the conclusions of wide ranging fires that exceed the 800°C mark. Their results of fires accelerated by the most combustible 'workstation areas' do not exceed, I believe, at any time 1000°C, not sufficient to melt massive steel RSJ structures that are all tied together and in themselves thus form a HUGE HIEAT SINK . That would conduct presumably, heat away from the central region of fire. The hotter the fire, the faster the rate of conduction of heat, through conduction via the metal structures. These fire damage experiments are also dependant on the unknowns of window damage, hence increased drafts and damage to the escalator section of the central core that had been designed & built in three staggered sections expressly with the intent of excluding fire accelerating draughts in exactly this kind of scenario.. Recall the buildings had been designed for aircraft impacts.

They do not seem to be able in the least to be able to explain in any way how the 'central-core' of 47 RSJ beams all collapsed to the ground, when their own pictograms in the above mentioned report show only, if I recall, 2 on some floors and, was it 5 on other floors having been severed directly opposite the aircraft impact zone(s) within the towers.
I have not had time to read in full this exhaustive document, however it is only based on experiment and various fire simulation models apparently. As you say, a lot of what they know, tangibly, is based on eye- witness reports.
Those comments are most helpful as they allow the debate to include all eye-witness accounts from fire-fighters to amateur cameramen to be considered N'est-pas?

Indeed people are doing so.

I intend to try and make some time to do the required reading. However, there are those above-mentioned conclusions by the NIST themselves, that can already be ascertained. That:
1) Fire and aircraft impact alone, considering the resultant fires not sufficient for total collapse to ground. I believe that they have not attempted to elaborate on a qualified mechanism for this collapse. They have admitted that a lot of what they know is based on eye-witness reports. Such reports are still emerging.
2) Why did the 'central core' collapse, when it had likely not been damaged sufficiently to do so.

The reason I have been suggesting other sources of information that do not exclude by default the testimony of other eye-witnesses than those the NIST has chosen, is that the NIST investigators have had to admit they do not accept that fires alone could have been responsible for collapse, neither could they explain around the issue of why the entire height of the 'central-core' collapsed, nor why because of the buildings structure it did not topple from the top third section, sideways down into the surrounding streets, rather than falling vertically down.

So I downloaded the 17Mb report and read the abstract and some of the findings concerning the impact and fall of WTC1 and WTC2. Here the degree of damage seemed to be much more extensive than in the selected "quotes" provided by the erstwhile spoon-feeder.

May I ask if you have any professional interest in this? Since, I have several times drawn attention to the fact that the then leaseholder of the entire complex admitted on PBS TV, (available everywhere as 'from the horse mouth' evidence') to having decided to 'go ahead and pull WTC7'. This building was the furthest away from WTC1 &2 , virtually undamaged, yet subsequently came down in true 'controlled demolition style'. This is what has been labelled as the "smoking gun" for alternative explanation hypotheses. To PULL WTC7 as SilverStein admits, requires that demolition charges had to have been in place before the day. You can't do it in the middle of a war-zone.
It was a magnificent demolition job, straight down. No mess, no fuss & the WTC5 next door but one, was still standing next to the debris of 7.

I've really got to get on with my life now, so nice talking to you and wish you all the best with your reading.
Courses to do, tutors to telephone......It's an exciting life.

Hi,
WTC 7 fell several hours after the twin towers. There were few minor fires inside it. It fell as all the film shows into its own footprint, that's vertically down. It was the building furthest away from the other 6 in the complex, all of which fell that day.
I still have the original Full page news sheet spreads from the day, where it is possible to see all buildings, and WTC 7 was a long way off. If you do suggest that blast may have caused concertina like collapse that does at least infer there were explosions. This is denied in the official reports. In the official reports all the buildings were brought down by fire and it's effects.

WTC fell at very close to 9.8m per second per second. That's near to free fall.

Once again. The owner admitted, perhaps in a moment of lapsed attention, under pressure, to having decided to ' PULL' World Trade Center tower 7 on the day of 9th September just hours after the collapse of the other buildings

I am not keen to enter into discussion with individuals about this, for the following reasons.
1) I want them to, if they decide, to take an interest to follow through naturally themselves.
2) Already there are folk here who are trying to have my conference access removed. They assume they have shut me up by mockery and when I bounce back with an encouragement to other conference user's that they should do this research for themselves, mixed with a little light hearted humour to help down the medicine they dream of shutting me up permanently.

THIS, is what 911 is all about. No, not about listening to the debate about all the evidence that conflicts with official explanation but about creating a worldwide dumming down on the rights of the human being and it's generic privilege to try and exercise free-speech. That, I think over the last few years has been clearly evidenced even for those that only watch BBC News 24.
Fortunately we do have the Internet. To suggest that all the NEWS from alternate sources, we read on the World Wide Web is garbage by default is a travesty of the worst kind.
I consider such strategies a conspiracy. A conspiracy against the unravelling of the full story on any matter.
I understand the Internet, having based my entire life in the field of electronic communications. I know that it has the power to enhance human thought and then more challengingly to encourage us to build greater self-esteem through knowledge.

Perhaps the fact that so much of the activity on the Internet is essentially free content, is what annoys the critics. If we all had to subscribe, financially to every online broadsheet or bulletin board, then perhaps critics would consider it a more valid medium. I don't know but that's certainly not going to happen.

For the reason that I feel my right to access of this conference may be being put into jeopardy, for whatever reason, I have never intended to maintain a discussion of science & 911 here.
There are millions of human hours being dedicated to that cause elsewhere, and it is having the expected effect.
Those who do not like a consideration of SCIENCE & ETHICS in the investigation of events that have, without doubt changed our world, probably in permanence, are seeking to silence the debate.

As for me.
I am out of here. YOU People are on your own. I encourage you to watch less TV, and research this stuff. If I wasn't doing this I'd be watching some TV.
--------------------------

T Jon 4 writes:
Derek M. Morison on 06 July 2006 at 13:11 +0000 wrote:
I'm slightly disappointed at the negative response.

Since there was nothing worth watching on the box I downloaded it and watched all 2hrs 13 min 40 secs of it. There was some remarkable film footage and unanswered questions about WTC6 and WTC7, two buildings on the World Trade Centre site that collapsed in the same way that obsolete high rise blocks collapse when explosive domolition charges are used to bring them down. Why they collapsed will probably never be known as the steelwork that supported their internal structure was cleared away and sold as scrap. How an alledged team of demolition experts/terrorists got into the buildings and planted the explosives unobserved was never answered. More of a job for structural engineers than the CIA/FBI IMHO.
TAJ
--------------------------

09 July 2006 13:44:35
Science chat
From: Kate Graham
Subject: Re(12): Scientific Truth
To: Science chat

R N. I on Sunday, July 9, 2006 at 13:23 +0000 wrote:
science is about critically evaluating evidence before forming opinion

Whereas conspiracy theories work on this sequence:

(a) Decide the conclusion.
(b) Cherry-pick, twist, or make up evidence to support it.
(c) When someone says it's ludicrous, bring on the out-of-context psychobabble.
(d) When nobody is convinced, conclude that this is due to a further conspiracy. Go to (a).

Kate
--------------------------------

06 July 2006 13:51:09
Science chat
From: Robert A. Dickinson
Subject: Re(4): Scientific Truth
To: Science chat

I agree with Terry. It seems that he has made observations that fit the conspiracy theories. There are probably many other explantaions as to why things happend the way they did other than the use of explosives.

To suggest that there was some kind of government coverup to kill civilians en mass just as an excuse to go to war is disrespectful to those that died that day and to the soldiers dying out there now.

I'm sorry but as a scientist I can't take anything I see or read on a conspircy therory web site seriously. They often cherry pick facts to fit their tin pot theories, at the expense of the more crediable evidence. If more primary research were done to prove or disprove these theories (on the WTC 9/11) and then published in reputable journals then maybe it could be taken seriously.

Rob

Grahame Stewart on Saturday, July 8, 2006 at 23:30 +0000 wrote:
I have never intended to maintain a discussion of science & 911 here.

That's obvious :-) Kate

--------------------------
09 July 2006 13:23:15
Science chat
From: Richard N. Irwin
Subject: Re(11): Scientific Truth
To: Science chat

Grahame Stewart on 09 July 2006 at 03:13 +0000 wrote:
Yeah you really do pick up on details. As scientists are supposed to do...I only added that stuff tonight after people started looking to contacting moderators.

Another conspiracy theory arises - the request for information on how to contact a moderator may be purely that. A request for information duly answered. One might surmise that to infer otherwise is somewhat strange, assuming malicious intent in something that is probably just a coincidence. Perhaps Andrea doesn't like the Welshist attitude in the other current thread. Perhaps Andrea is looking to volunteer as a moderator and wants to get some inside info on what it's like... the possibilities are almost infinite, but perhaps these alternatives don't fit the scheme so well.

If you think science is about laying stumbling blocks science is about critically evaluating evidence before forming opinions - we are trying to evaluate the evidence you present. Perhaps we are having trouble because of the perception of your internet sources, which don't seem to be rigorously peer-reviewed in the way that we usually expect. They appear to be from sources that are equally controlled by vested interests as any official propaganda sites.
The usual way forward in science is to propose hypotheses and then test them with rigour. My impression is that it is fine for you to ignore any alternate hypotheses we suggest but you seem very upset when we have the temerity not to accept yours at face value.and then looking for errant or upset behaviour from those with differing opinions then that's maybe another reason why the British scientific community is forever falling on its A*SE.I haven't fallen on my A*SE since about 1994 when skiing on a forested slope.

I'm a human being, not a lab rat.

I'm a lab rat and proud of it. Don't you forget it. We only have your word for it at the moment - you may well be some avatar created in silico with no physical presence in my version of the real world, but I'm happy to apply Occam's razor and accept that you propably are a human being.
Gram € :-| )
--------------------------

08 July 2006 07:22:09
Science chat
From: Ch Dr-Br,oufcnt1.open.ac.uk
Subject: Re(5): Scientific Truth
To: Science chat

Robert A. Dickinson,oufcnt2.open.ac.uk writes:
He does not conceed that there may be ulternative explanations to the way the WTC collapsed
Like gerry building? Just because it was a magnificent building, does not mean that the builders might not have taken a few short cuts. Also why did the hijackers then fly stolen airplanes into the building? If it was a government plot, surely it would have been better to wait for it to fall down anyway?
--------------------------

06 July 2006 22:11:30
Science chat
From: Kate Graham
Subject: Re(5): Scientific Truth
To: Science chat

Grahame Stewart on Thursday, July 6, 2006 at 19:44 +0000 wrote:
I of course object to being called a spammer as I am doing a BsC in computer software development,

Oh fair enough then.
Kate
-------------------------

06 July 2006 08:51:52
Science chat
From: Robert A. Dickinson
Subject: Re: Scientific Truth
To: Science chat

The trouble with the USA (and the internet) is its full of conspiracy theorists who dont beleive a word they are told. There is always a hidden aggenda.